The remnants of Hurricane Larry dropped abundant snowfall on Greenland just as the summer melt season was coming to an end.
Hurricanes are known for their destructive wind, rain, and storm surge. Hurricane Larry delivered more than that. On September 12, 2021, the storm’s remnants dropped abundant snowfall on Greenland just as the summer melt season was coming to an end.
Snowfall amounts on that day are visible in the map above, as represented by the Goddard Earth Observing System (GEOS) model. Snowfall amounts are shown as millimeters of water, as opposed to snow depth, for the 24-hour period. Fifty millimeters of water is equivalent to about 250 millimeters (10 inches) of snow, assuming the snow has a density of 250 kilograms per cubic meter.
Through early September, Hurricane Larry traveled northwest across the Atlantic Ocean reaching a peak strength of category 3 on the Saffir-Simpson wind scale. It weakened as it turned north, staying well offshore of the U.S. East Coast, and then made landfall as a category 1 storm over Newfoundland in eastern Canada on September 11.
Next, Larry reached Greenland on September 12 as a post-tropical storm, delivering high winds and copious snowfall to the island’s southeast and interior. Kulusuk and Tasiilaq saw winds gusts topping 90 miles (145 kilometers) per hour and blizzard conditions were reported at Summit Station.
“Such storms are quite rare,” said Lauren Andrews, a glaciologist with NASA’s Global Modeling and Assimilation Office. “They generally dissipate well before reaching as far north as Greenland. Though there have been similar storms, including Noel in 2007 and Igor in 2010.”
Andrews also noted that it is unusual to see such a high rate of snowfall so soon after the end of the summer melt season, which occurs each year from around May to early September. In fact, the recent snowfall from ex-hurricane Larry could potentially balance out losses from melting during the summer, which included three notable melting events—two in July and one in August.
“It is a dramatic end to a season of extreme events across the Greenland ice sheet,” Andrews said.
Once the satellite data are fully processed, scientists will be able to gauge the state of Greenland’s mass balance. A positive mass balance means that more snow was gained than was lost through processes such as melting and runoff. So far, Andrews said, “It looks like 2021 will end up having an above average surface mass balance.”
NASA Earth Observatory image by Joshua Stevens, using GEOS-5 data from the Global Modeling and Assimilation Office at NASA GSFC. Story by Kathryn Hansen.
30th July 2021
Snowfall Happens In 13 Cities Of Cold snap-Hit Brazil - Report
A fierce cold snap led to snowfall in Brazil in an unusual wintry phenomenon. The last time a blizzard hit Brazil was in 1957, according to USA today.
At least 13 cities in the Brazilian State of Río Grande do Sul Wednesday recorded snowfalls, a rare event for the region, but one that has come to be due to this year's harsh winter temperatures.
Snow was recorded in cities such as Pelotas, São Francisco de Paula, Gramado, Carlos Barbosa, Bagé, Herval, Piratini, Caxias do Sul, Marau and Farroupilha, it was reported.
The wave of cold air that passes through southern Brazil brought snow to at least 13 cities in Rio Grande do Sul, in addition to frozen rain.
According to Somar Meteorologia, there was snowfall in Pelotas, São Francisco de Paula, Gramado, Carlos Barbosa, Bagé, Herval, Piratini, Caxias do Sul, Marau and Farroupilha, where children took to the streets to celebrate and build up snowmen, which are very foreign to the area.
Other parts of Rio Grande do Sul were less blessed by nature and instead of snowfalls they recorded hail-like phenomena, such as “frozen rain” (when water droplets freeze when fallinf off the cloud, but melt when they touch the ground).
Snowflakes descend from clouds in a region that is quite cold and fall in a region of the atmosphere that is warm. The phenomenon was registered at least in Júlio de Castilhos, Nova Petrópolis, Itaara, Tupanciretã, Canguçu and Lavras do Sul.
In addition, according to Somar Meteorologia, there was graupel, which is a small granule of ice created when drops of super-cooled water cover a snowflake. graupel is white, opaque, soft and can easily fall apart in your hand, and it is also generally smaller than hail, with a diameter of about 0.2cm to 0.5cm.
A historic wave of cold is passing through Brazil, bringing snowfall to the southernmost state of Rio Grande do Sul, the G1 news portal said.
On Wednesday it snowed in at least 13 cities, including Pelotas, Sao Francisco de Paula, Carlos Barbosa, with hail registered in some cities, according to the Brazilian news outlet. People took to the streets to have snowball fights and make snowmen.
Meteorologists forecast temperatures down to -10�C (14�F), with record low temperatures likely to be registered in southeastern cities this Friday and Saturday.
In the southern state of Santa Catarina, thirty districts registered temperatures lower than -7�C (19.4�F). Rio de Janeiro reported 4-meter (13-foot) waves.
The cold is expected to affect next year's coffee crop heavily, since the low temperatures have hit Brazil in the heart of its coffee belt. Cooxupe, the largest private coffee cooperative around the globe, sent technical specialists to assess the possible damages to coffee plantations.
Day after day of 90-plus-degree heat and high humidity has forced organizers to reschedule rugby matches and mountain biking competitions and move some track and field events to early morning hours or dusk to avoid the roasting afternoon sun.
Other events, like the marathon and race walking, have been moved completely out of Tokyo to the cooler city of Sapporo, capital of the mountainous northern Japanese island of Hokkaido and the site of the 1972 Winter Olympics.
For the athletes competing in Tokyo, the organizers have erected cooling tents, hauled in water-mist fans and started providing ice cream to the army of volunteers helping run the Games.
Compared to 1964, which was the last time Japan hosted the Summer Olympics, the July and August temperatures in Tokyo are 2.7 degrees warmer, and there are now, on average, eight more days of 95-plus-degree weather than there were 57 years ago, Prociv said.
“If you start to feel lightheaded, nauseated or confused, stop and seek medical care,” he added. “Heatstroke can often go unnoticed until an athlete is in the danger zone, and that can be life-threatening.”
Article by Corky Siemaszko, NBC
wave Corky S is a senior writer for NB Olympic organizers battle to 1ST JULY
Posted 1 st July 2021:
Death Valley Hits 130 Degrees as Heat Wave Sweeps the West 54.4c...Not yet Highest !!
Western Canada burns and deaths mount after world’s most extreme heat wave in modern history
It's not hype or exaggeration to call the past week's heat wave the most extreme in world weather records.
byBOB HENSON and JEFF MASTERS The poster community of this horrific episode has to be Lytton, British Columbia. The town broke Canada’s longstanding all-time national high temperature of 45 degrees Celsius (113 degrees Fahrenheit) with a high of 46.6°C (116°F) on Sunday, June 27. The next day brought 47.9°C (118.2°F), and Tuesday a stunning 49.6°C (121°F). The lighting from the dry thunderstorms (pyrocumulonimbus) that developed was so intense that over 700,000 intracloud and cloud-to-ground lightning flashes were recorded in 15 hours, including more than 100,000 cloud-to-ground strikes. That’s about 5% of the total number of lightning flashes Canada typically sees in an entire year https://twitter.com/i/status/1410436497329721348...Chck the pyro cumulonimbus developing and the lightning within ! Extraordinary ! The World's Highest on 2nd July !
Maximum Temperature Last 24h - 07/03/2021 at 06:00 UTC
Coldest inhabited place on Earth is baking in record heat
ByZachary Rosenthal, AccuWeather staff writer
Oymyakon, Russia, which is widely considered the coldest inhabited place on Earth, is not living up to its reputation.
The town hit a maximum recorded temperature of 88.8 degrees Fahrenheit (31.6 degrees Celsius) on Tuesday, the hottest it has ever been in June. The last three days in Oymyakon have been similarly hot, with temperatures reaching 86 F.
AccuWeather Senior Meteorologist Jason Nicholls says that the weather will continue to cool off a bit, with observed high temperatures in the upper 70s on Thursday and then forecast in the upper 70s again on Friday, but that the heat will return over the weekend.
"It looks to turn warmer again on Saturday with highs around 30 C (86F). Not quite as warm Sunday but still warm by Oymyakon standards, getting up to 82 F (28 C)," Nicholls said.
Located in the Sakha Republic of Russia, the town of about 500 residents typically endures frigid temperatures. According to The Siberian Times, the lowest officially recorded temperature in Oymyakon was -67.7 below zero C in 1933.
This past January, temperatures in Oymyakon plummeted to an extremely frigid -73 F, meaning temperatures in the city have varied by a whopping 161 degrees Fahrenheit this year.
Oymyakon is in a permafrost region, meaning that there is ground which continuously remains below 32 F (0 C).
Oymyakon is about 200 miles south of the Arctic Circle, a region many people assume is cold year-round, but the air there can get warm as recent thermometer readings demonstrate.
On June 24, in Inuvik, Northwest Territories, Canada, which is 100 miles north of the Arctic Circle, the temperature hit 86 F. In Little Chicago, Northwest Territory, Canada, the temperature reached 91 F.
This past week, the Pacific Northwest also experienced all-time record heat. Portland shattered its daily high-temperature record three days in a row; the record currently stands at 116 F. In Canada, a new all-time high temperature was set in Lytton, British Columbia, where the mercury shot up to 121.1 F (49.5 C) on Tuesday, according to the BBC.
Heat wave leaves Moscow sweltering under temps not reached since 1901
ByMaura Kelly, AccuWeather meteorologist
A blistering heat wave that has been enveloping eastern Europe nudged its way into western Russia this past week, challenging Moscow records that have stood for more than a century and forcing the city to face heat rarely felt in this region of the world.
On Tuesday, parts of Moscow reached 94.5 degrees F (34.7 degrees C), according to an official reading by the Russian weather service Roshydromet, which ties the all-time June record set in 1901.
Preliminary temperature reports show the Russian capital reached 95 F (35 C) on Wednesday, which may break the record high temperature for June. Then, the high reached 93 F (34 C) on Thursday.
This highest temperature ever recorded in Moscow, 100.4 F (38 C), was recorded in July 2010 when a heat wave engulfed western Russia and wildfires were common across the region, AFP reported.
St. Petersburg, located about 370 miles (600 km) to the northwest of Moscow, also hit 94 F (34 C), 92 F (33 C) and 97 F (36 C) on Monday, Tuesday and Wednesday, respectively. These are some of the highest temperatures for the city since 1998, according to AFP.
Heatwave Scorches the Middle East
June 6, 2021
With meteorological summer just underway, some parts of the Northern Hemisphere were already feeling the heat in early June 2021. In particular, the early-season heat has been scorching countries across the Middle East.
The map above shows air temperatures in the region on June 6, 2021. The map was derived from the Goddard Earth Observing System (GEOS) model and depicts air temperatures at 2 meters (about 6.5 feet) above the ground. The darkest red areas are where the model shows temperatures around 50°C (122°F).
The GEOS model, like all weather and climate models, uses mathematical equations that represent physical processes (such as precipitation and cloud processes) to calculate what the atmosphere will do. Actual measurements of physical properties, like temperature, moisture, and winds, are routinely folded into the model to keep the simulation as close to observed reality as possible.
Indeed, local ground stations recorded temperatures that climbed above the 50°C mark in at least four Middle Eastern countries, including Iran, Kuwait, Oman, and the United Arab Emirates (UAE). According to news reports, Sweihan in the UAE hit 51.8°C (125.2°F) on June 6, 2021, which was the country’s highest temperature on record for the month of June. Countries in Central and South Asia were also reported to have seen extraordinarily high temperatures for the time of year.
Meteorologists at The Washington Post reported that the heatwave is the result of a “heat dome.” The phenomenon occurs when high pressure in the mid- to upper-atmosphere acts as a cap, trapping warm air as it rises and pushing it back toward the surface to warm even more. A notable occurrence of the phenomenon caused temperatures to soar across the Middle East in July and August 2015. The heatwave this year comes about a month before the hottest temperatures of the season typically arrive.
Troliest named tropical storm in a calendar year in the Eastern Pacific on record.
---------------------Breaking the record of 2017 Storm #Andres is the earliest named tropical storm in a calendar year in the Eastern Pacific on record.
Breaking the record of 2017Tropical Storm #Andres is the earliest named tropical storm in a calendar year in the Eastern Pacific on record.
Breaking the record of 2017 named tropical storm in a calendar yeFebruary 25, 2021
The Extreme Temperature Changes of Texas
Few places in the world experience more rapid and extreme temperature changes than Texas.
A place whether the temperature can be 80F at noon and 15F by midnight.
A state where a phenomenon called the Blue Norther can produce extreme winds with rapid temperature declines.
Consider the case Austin, Texas, a city that not a few Northwesteners are thinking of moving to. Below is a figure that shows the observed highs and lows (black bars), as well as the normal temperature range (green band) and the record highs and lows for February.
In the beginning of the month, temperatures were above normal, with some days offering highs around 80F. But then around Feb. 10th, the bottom dropped out, with lows getting to 6F on Feb. 16tth. And later in the month, they were above normal again. Texans have to be a tough breed to deal with these changes!
Look closely at the record highs and lows. Record highs are in the 80s in the early part of the month and around 100F by the 21st, while record lows are in the single digits to the teens. And it is not unusual to gyrate between the two quickly.
The rapid transition from summer warmth to Arctic cold is not usual in Texas--so frequent that they have a name for it, the Blue Norther. Sometimes called the Texas Norther.
Moderate blue northers (temperature declines of 10-20F), typically occur several times per year, and the mega-events, like this month (with temperature declines of 30-60F), happen every decade or so.
Such very large temperature declines have been noted as long as Texas has been occupied and is certainly not a new phenomenon. Texas cold waves are not the result of the "global weirding" that is so popular in the press but a natural part of Texas weather.
From Cliff Mass Weather Blog
22nd February 2021
Fact check: It is snowing in Saudi Arabia…and it is not rare
By Satya Priya BNPublished on 22 Feb 2021 1:40 PM
18th February 2021
From Paris to Athens, from Hawaii to Texas, Heavy Snow Blankets the Globe
Old Man Winter is living up to his reputation this month across the Northern Hemisphere, with heavy snow reported in places that don’t see snow too often. Two weeks ago, 1 to 2 feet of snow fell on the Big Island of Hawaii; since then, additional snow has fallen across the higher elevations of both Hawaii and Maui islands. Just last week, Paris was hit by a severe winter storm, encasing famed attractions like the Eiffel Tower in snow and ice. Greece turned into a winter wonderland yesterday, with Athens seeing its biggest snowfall since 1987. And now the United States is dealing with what seems like an endless parade of winter storms, including one which brought snow and freezing temperatures to the Texas Gulf Coast. Yesterday, snow blanketed 73% of the continental United States, which is the greatest greatest extent of snow cover on record in the database, which dates back to 2003.
A new record was set yesterday (based on data back to 2003) of the most snow cover across the continental U.S. Image: NWS
The recent snow has also been joined by cold blasts. The United Kingdom, along with large parts of northern Europe, is starting to that-out from unusually cold period of weather. Just days ago, on February 11, the Scottish Highlands village of Braemar -23.0°C (-9.4°F), the United Kingdom’s coldest temperature since 1995 and the coldest February temperature since the 1950s. Asia has been cold too. Earlier this month, authorities were fearing blackouts would roll through Japan due to a shortage of powerplant capacity in cold weather conditions and a shortage of fuel needed for those electrical generating stations.
Cold and snow is even popping-up in the southern Hemisphere. Just weeks ago, cold and snow arrived in southern New Zealand. While it’s the middle of summer in the Southern Hemisphere, more than 3″ of snow fell at the Cardrona Alpine Resort on the country’s south island, south and west of Christchurch....Weatherboy
7th February 2021
Snowstorm pounds parts of Europe; Germany, Britain, Lithuania and Netherlands turn winter landscapes
Snowstorm and strong winds pounded parts of Europe on February 7, turning the Netherlands, England, Germany and Lithuania into winter landscapes. The unusual weather and temperature divide was caused by a polar vortex pushing icy air from the Arctic toward northern and western regions of the continent.
7th February 2021
U.S. and North America;
DANGEROUS COLD: Early this morning we were on the southern edge of a large Arctic air mass. It was -47° at Yellowknife in the Northwest Territories of Canada, while it was 61° in Dallas, TX. The pattern is set up so that we will be a part of this expansive Arctic air for 7-10 days. The temperature contrast is also responsible for our snow chances. More on the snow below.
January 11th 2012
Between January 7–9, 2021, a moist, low-pressure weather system over the ocean collided with a cold air mass sitting over western Europe. The result was the heaviest snowfall over Spain in fifty years.
After barely seeing significant snowfall for a decade, the capital city of Madrid was blanketed with widespread accumulations of 20 to 30 centimeters (8 to 12 inches). Some suburban and rural areas in central, northern, and eastern Spain were coated with up to 50 centimeters (20 inches) of snow.
January 5th 2021
AUSTRALIA: THE WARMEST DAY IN HISTORY – THE HEAT WAVE CONTINUES
In Australia, it is warmer than at any time since weather records began in 1910. According to an analysis by the Australian Weather Service, the average high temperature on Tuesday was 40.9 degrees. The previous record was 40.3 degrees and it was measured in January 2013. The average temperature extremes across the country are the most accurate measurement of a heat wave.
Current temperatures reach 16 degrees above the long-term average.
January 8th 2021
The nights have been very cold in the Iberian Peninsula, but Spain wins the record-low-temperature prize
Several stations, some run by meteorological aficionados but who record values in real time, believe that the temperature of -34.1ºC (-29.4ºF)has been reached in Clot del Tuc de la Llança, in the Pyrenees, in the province of Lérida.
The negative temperature of -34.1ºC was first recorded by ” Projecte 4 Estacions “. Two unofficial meteorological organizations, the website “Meteo Valls d’Àneu” and “MeteoPirineu.com” say the cold record was set at 4.19 pm this Wednesday in Spain . Both sites receive data from a weather station installed at a ski resort, according to the newspaper “La Vanguardia”.
The Aragon delegation from the State Meteorological Agency and Noromet and the Meteorological Association of the Northwest Peninsular, have both officially recognized the figures. However, the record has not yet been validated by the Meteorological Service of Catalonia , where Clot del Tuc de la Llança is located .
The Spanish press says the number of -34.1ºC is considered very likely. “La Vanguardia” says this beats the record set in 1956 of -32ºC in Estany Gento (a lake of glacier origin), in Vall Fosca , in the Spanish municipality of Torre Cabdella .
In the last few days, negative temperatures have been constant in Spain , especially in mountainous regions. In the Navarra region, for example, on Tuesday night some areas of the Pyrenees and the Urbasa mountain range registered values below -10ºC.
December 28th 2020
Britain will be buried in up to SIX INCHES of snow before New Year's Day: Met Office issues four-day warning for large swathes of the country - including London
13:00 GMT Jersey Airport 10:00 GMT Scilly, Saint MaryS 12:00 GMT Jersey 12:00 GMT Valentia Observatory 11:00 GMT Scilly St Marys 12:00 GMT 12:00 GMT Isle Of Man 08:00 GMT Guernsey Airport 09:00 GMT Alderney / Channel Island 05:00 GMT Chivenor 13:00 GMT Belmullet 12:00 GMT Bridlington Mrsc 04:00 GMT Camborne 13:00 GMT Ronaldsway 08:00 GMT Isle Of Portland 00:00 GMT Malin Head 13:00 GMT Valley 10:00 GMT Culdrose
December 29th 2020
It’s time to look at sea ice habitat at 15 December (Julian Day 350), now that virtually all bears except pregnant females throughout the Arctic are either out on the sea ice attempting to hunt for seals or hunkered down against the darkness.
As is usual at this time of year, the Canadian Archipelago, the Beaufort, East Siberian and Laptev Seas are well covered in ice (see regions on map below). As for the rest, despite what one polar bear specialist has implied there is no evidence that a slower-than-usual fall freeze-up in the other peripheral seas of the Arctic negatively affects polar bear health or survival.
November 30th 2020
NSW heading for severe Heat wave this week:
Record Heatwave in Sydney Australia:
Sydney recorded its hottest November night as Australia's largest city suffered through a weekend heat wave that saw daytime temperatures peak above 40 degrees Celsius.
The temperature reached above 40 degrees for the second consecutive day yesterday.
The overnight temperature did not drop below 25.3 degrees, making it the hottest November night on record.
On November 22, 2020, Cyclone Gati became the strongest storm to hit Somalia since satellite records began five decades ago. Gati made landfall with maximum sustained winds of 170 kilometers (105 miles) per hour, a category 2 storm on the Saffir-Simpson scale. The storm brought more than a year’s worth of rain to the region in two days. Local authorities report at least eight people were killed and thousands have been displaced.
In 12 hours, Gati’s winds intensified from 65 kilometers (40 miles) to 185 kilometers (115 miles) per hour—the largest 12-hour increase for any tropical storm ever recorded in the Indian Ocean. The storm rapidly intensified due to its small size, warm Indian Ocean waters, and low wind shear. Although the storm slightly weakened before landfall, Gati brought exceptional amounts of rain to northern Somalia.
Much of northern Somalia, which typically receives about 10 centimeters (four inches) of rain in an entire year, received at least that much in two days. The city of Bosaso reported 12.8 centimeters (5 inches) in 24 hours.
November 2nd 2020
Nepal recorded its hottest November day ever with 35.5C at Bhairawa, the previous record was 35.2C at Dipayal in 2001.....From Max.
‘The Northern Hemisphere winter of 2020/21 is shaping up to be a doozy,” says reader Martin Siebert.
The latest CFSv2** forecast for region 3.4 of the central equatorial Pacific Ocean reveals that a flip from the recent El Niño setup (warming) to a La Niña one (cooling) has occurred.
CFSV2 FORECASTS LA NIÑA (COOLING) INTO 2021
La Niña’s are usually associated with coolerglobal average temperatures, droughts in the southern U.S., and anomalously wet conditions in Australia.
The latest CFSv2 forecast for region 3.4 of the central equatorial Pacific Ocean reveals that a flip from the recent El Niño setup (warming) to a La Niña one (cooling) has occurred.
The below chart shows Sea Surface Temperatures (SSTs) for region 3.4. of the equatorial Pacific: that black-dash line has dipped deep into La Niña territory, and the model sees this persisting through the remainder of 2020 and into 2021:
October 15th 2020
October 10th 2020:
Louisiana has now had four named storm landfalls in 2020 (Cristobal, Laura, Marco and #Delta). 2020 is now tied with 2002 for the most Louisiana named storm landfalls in a single season on record. In 2002, Bertha, Hanna, Isidore and Lili made landfall in Louisiana.
The most recent October Louisiana #hurricane landfalls by Saffir-Simpson category are: Category 1: Nate (2017) Category 2: Hilda (1964) Category 3: Texas-Louisiana Hurricane (1886) Category 4: Chenier Caminanda (1893) Category 5: None on record
Delta is the 10th named storm to make landfall in the continental US this year - the most in a single Atlantic hurricane season on record. Prior to 2020, the most named storms to make landfall in the continental US was 9 set in 1916
Info by Vagarian Vineet Kumar (IITM )
September 28th 2020:
Coldest Northern Hemisphere temperature, first recorded by UW, officially confirmed
MADISON, Wis. — Nearly 30 years after recording a temperature of minus 93.2 degrees Fahrenheit (minus 69.6 Celsius) in Greenland, the measurement has been verified by the World Meteorological Organization as the coldest recorded temperature in the Northern Hemisphere.
The measurement was first recorded by a University of Wisconsin-Madison Antarctic Meteorological Research Center Automatic Weather Station in December 1991. An AWS is a standalone instrument suite developed by UW-Madison Space Science and Engineering Center and AMRC scientists and engineers to collect numerous environmental parameters such as air temperature, pressure, humidity, wind direction and speed. The information is then relayed via satellite back to SSEC in near real time.
Extreme measurements like that in Greenland undergo a rigorous review process to make sure they are accurate and there is agreement with other meteorological data and weather forecast models. Due to the quality and preservation of the AWS station data provided by the Antarctic Meteorological Research Center, the WMO was able to verify the 1991 temperature and log it as part of the official record.
According to Weidner, this cold temperature was the result of several atmospheric conditions converging in a specific way.
The Klinck field site, where the coldest temperature was measured, is located in the middle of Greenland at an elevation of 10,170 feet (3,100 meters). Extreme cold air temperatures can occur when there is little wind to disturb an area, accompanied by clear skies.
In this case, the elevation and a splitting of the jet stream — which usually flows over the Greenland ice sheet — created a dead zone, allowing the already cold region to continue losing heat from the Earth. Similar conditions occur over Canada and result in the famed (or infamous) “polar vortex,” which produces extreme cold that reaches the U.S.
September 24th 2020
Big Chill...U.K. to be Battered by Torrential Rains and Gales...Temperatures to Plunge...Artic Blast to Hit U.K.
Using satellite technology, NASA determined that between 2003 and 2019, global fires have dropped by roughly 25 percent. This makes the “climate change is worsening wildfires” argument completely moot.
The control of fire is a goal that may well be as old as humanity, but the systematic monitoring of fire on a global scale is a much newer capability.
In the 1910s, the U.S. Forest Service began building fire lookout towers on mountain peaks in order to detect distant fires. A few decades later, fire-spotting airplanes flew onto the scene. Then in the early 1980s, satellites began to map fires over large areas from the vantage point of space.
Over time, researchers have built a rich and textured record of Earth’s fire activity and are now able to analyze decadal trends. “The pace of discovery has increased dramatically during the satellite era,” said James Randerson, a scientist at the University of California, Irvine. “Having high-quality, daily observations of fires available on a global scale has been critical.”
The animation above shows the locations of actively burning fires on a monthly basis for nearly two decades. The maps are based on observations from the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite. The colors are based on a count of the number (not size) of fires observed within a 1,000-square-kilometer area. White pixels show the high end of the count—as many as 30 fires in a 1,000-square-kilometer area per day. Orange pixels show as many as 10 fires, while red areas show as few as 1 fire per day.
December 1, 2014 – August 31, 2015
The sequence highlights the rhythms—both natural and human-caused—in global fire activity. Bands of fire sweep across Eurasia, North America, and Southeast Asia as farmers clear and maintain fields in April and May. Summer brings new activity in boreal and temperate forests in North America and Eurasia due to lighting-triggered fires burning in remote areas. In the tropical forests of South America and equatorial Asia, fires flare up in August, September, and October as people make use of the dry season to clear rainforest and savanna, as well as stop trees and shrubs from encroaching on already cleared land. Few months pass in Australia without large numbers of fires burning somewhere on the continent’s vast grasslands, savannas, and tropical forests.
But it is Africa that is truly the fire continent. On an average day in August, the Moderate Resolution Imaging Spectroradiometers (MODIS) on NASA’s Aqua and Terra satellites detect 10,000 actively burning fires around the world—and 70 percent them happen in Africa. Huge numbers of blazes spring up in the northern part of continent in December and January. A half year later, the burning has shifted south. Indeed, global fire emissions typically peak in August and September, coinciding with the main fire seasons of the Southern Hemisphere, particularly Africa. (High activity in temperate and boreal forests in the Northern Hemisphere in the summer also contribute.)
August 29, 2018
The second animation underscores how much fire activity shifts seasonally by highlighting burning activity during December 2014, April 2015, and August 2015. The satellite image above shows smoke rising from the savanna of northern Zambia on August 29, 2018, around the time global emissions reach their maximum.
Though Africa dominates in the sheer number of fires, fires seasons there are pretty consistent from year-to-year. The most variable fire seasons happen elsewhere, such as the tropical forests of South America and equatorial Asia. In these areas, the severity of fire season is often linked to cycles of El Niño and La Niña. The buildup of warm water in the eastern Pacific during an El Niño changes atmospheric patterns and reduces rainfall over many rainforests, allowing them to burn more easily and widely.https://www.youtube.com/embed/69N494UIlS8?flag=1&enablejsapi=1&html5=1&origin=https://earthobservatory.nasa.gov
Despite the vast quantities of carbon released by fires in savannas, grasslands, and boreal forests, research shows that fires in these biomes do not generally add carbon to the atmosphere in the long term. The regrowth of vegetation or the creation of charcoal typically recaptures all of the carbon within months or years. However, when fires permanently remove trees or burn through peat (a carbon-rich fuel that can take centuries to form), little carbon is recaptured and the atmosphere sees a net increase in CO2.
That is why outbreaks of fire in countries with large amounts of peat, such as Indonesia, have an outsized effect on global climate. Fires in equatorial Asia account for just 0.6 percent of global burned area, yet the region accounts for 8 percent of carbon emissions and 23 percent of methane emissions. On October, 25, 2015, the Earth Polychromatic Imaging Camera aboard the DSCOVR satellite acquired an image (below) of heavy smoke over Indonesia; El Niño was particularly active at the time.
October 15, 2015
One of the most interesting things researchers have discovered since MODIS began collecting measurements, noted Randerson, is a decrease in the total number of square kilometers burned each year. Between 2003 and 2019, that number has dropped by roughly 25 percent.
As populations have increased in fire-prone regions of Africa, South America, and Central Asia, grasslands and savannas have become more developed and converted into farmland. As a result, long-standing habits of burning grasslands (to clear shrubs and land for cattle or other reasons) have decreased, explained NASA Goddard Space Flight scientist Niels Andela. And instead of using fire, people increasingly use machines to clear crops.
“There are really two separate trends,” said Randerson. “Even as the global burned area number has declined because of what is happening in savannas, we are seeing a significant increase in the intensity and reach of fires in the western United States because of climate change.”
When researchers began using satellites to study the world’s fires in the 1980s, they were just sorting out the basics of how to detect fires from space. Now after mining MODIS data for nearly two decades, scientists are looking ahead to other satellites and technologies that they hope will advance the study of fire in the coming years.
A series of follow-on sensors called the Visible Infrared Imaging Radiometer Suite (VIIRS) on the Suomi NPP and NOAA-20 satellites now make near-real time observations of emissions that are even more accurate than those from MODIS because of improved fire detections along the edge of the edges of images, noted Andela.
Meanwhile, the launch of satellites with higher-resolution sensors is also helping. “The Landsat 8 and Sentinel satellites, in particular, are contributing to a revolution in our ability to measure the burned area of small grassland and forest fires,” said Randerson. “And we are going to need additional detection capabilities in the coming years to track increasingly destructive mega fires during all times of day and night.”
September 12th 2020;
see the fall in Max temperature at Denver in 2 days !38c to 13c !
First super typhoon of the year has formed in NW pacific. Name: Haishen. As of 5:30am ISTIt has a windspeed of 135 knots, making it the second most powerful cyclone of the year in the northern hemisphere
Info from Vag. Vineetkumar (Pune IITM)
September 3rd 2020:
Maysak typhoon with maximum windspeed of 125 knots is the strongest typhoon and only the first category 4 typhoon in entire pacific ocean in year 2020.
Its lowest pressure: 921 hpa
Durration with windspeed more than 65 knots : 4.5 days. Highest by any typhoon in entire pacific ocean this year
Last night, Hurricane Laura made landfall on the southwestern coast of Louisiana, bring heavy rain (6-8 inches), strong winds (gusting to 132 mph at one location), and a coastal storm surge (roughly 10 feet at the most vulnerable locations).
The NWS Lake Charles radar image at midnight central time showed a well defined eye as the storm was making landfall.
Now the dilemma and interesting part. Based on reconnaissance aircraft and other information, the National Weather Service’s National Hurricane Center had estimated that Laura was a Category Four hurricane just prior to landfall, and according to the official Saffir-Simpson scale, that means the sustained surface (10-m) winds, averaged over a few minutes, were between 130 and 156 mph (see below). Not gusts, sustained winds.
Saffir-Simpson Hurricane Categories
But here is the issue. What were the maximum sustained winds that occurred last night as Laura made landfall? Looking at all available stations, the highest sustained wind was 98 mph at Lake Charles Airport. The map below shows the sustained winds at 1 AM, when the storm was just moving inland (wind barbs show sustained winds, with gusts in red). The blue arrow indicates Lake Charles Airport.
Looking at the sustained winds, one would conclude that Laura was only a weak category two hurricane (96-110 mph).
And then there are gusts. Gusts are not used as part of the Saffir-Simpson hurricane scale, but, let’s face it, gusts are very important. The big damage in most storms are done by the gusts.
Below are the maximum gusts of Laura. Two locations are extreme: Calcasieu Pass on the coast and Lake Charles, a few miles to the north (127 and 132 mph gusts, respectively)
Such strong gusts are consistent with the destruction of the NWS radar dome at Lake Charles Airport–they are rated to handle up to about 135 mph. (see the before and after below).
So what is going on? How strong was the storm? Category two or four?
A key issue is friction and drag, which is much greater over land (with trees, hills, buildings, etc) that over the aerodynamically smooth water. As a result of this surface drag, winds decrease VERY rapidly over land, even if the hurricane remains relatively intact aloft.
Let me illustrate this visually, by showing you a forecast by the state-of-the-art NOAA/NWS HRRR model as Laura made landfall. These plots show surface (10-m) surface wind in knots (1 knot=1.15 mph)
Before landfall (9 PM PDT), a nice hurricane structure is apparent, with some winds getting to 90 knots in the eyewall.
But then as the storm makes landfall (1 AM PDT), you can see a profound weakening of winds over land.
And by 5 AM PDT, with the storm completely over land, the fastest winds are gone.
So even if the storm had category four sustained winds near the surface while it is offshore, the sustained winds decline precipitously when the store goes onshore.
But yet the storm can still remain very, very dangerous in the hours after landfall. Why?
First, even the reduced sustained winds (e.g., 90-100 mph in this case) can produce great damage.
But there is more. Gusts don’t necessarily decline as rapidly as sustained winds as the storm moves over land.
To illustrate this, here is a plot of the predicted gusts as the storm made landfall. Not as much a decline over land as for sustained winds. Gusts are caused by the intermittent mixing down of faster (higher momentum) air from aloft down to the surface. So even if winds are slower down lower, sometimes air from aloft…where the winds are still blowing hard…can be mixed to the surface. So gusts can hold out longer than sustained winds as a storm makes landfall.
The bottom line: a storm that was category four over water can still maintain a real “punch” over land, even after it nominally declines to a category two. Strong, damaging gusts can remain, even when the sustained winds decline.
28th august 2020 :Phoenix Has Record-Breaking Heat Wave With 50 Days Of 110°F...43.3c
Phoenix, Arizona Is In The Midst Of An Unprecedented Record-Breaking Heat Wave, Hitting Its 50th Day This Year With Temperatures Reaching 110 Degrees Or Higher On Friday.
Although scorchingly hot summer temperatures are common in the desert city, the current year has broken earlier records for consistently high temperatures by some distance. The previous record for the most days at 110 degrees or higher in one year was 33, which occurred in 2011.
On August 16, a temperature of 130 degrees was recorded at California’s Death Valley. The reading was the third-highest temperature ever recorded. The highest-ever temperature was also recorded at Death Valley, where a temperature of 134 degrees was observed on June 10, 1913, while 131 degrees was recorded in Tunisia on July 7, 1931.
Tokyo (CNN)Temperatures in central Japan tied for a national record on Monday, as the country sweltered under a scorching summer heat wave.
The mercury rose to 41.1 degrees Celsius (105.98 degrees Fahrenheit) in the central city of Hamamatsu, in Shizuoka prefecture on Monday, according to the Japan Meteorological Agency, matching the highest temperature ever recorded in the country, which was set in Kumagaya, a city near Tokyo, in July 2018.
Japan has been enduring an intense heatwave since the middle of last week, with multiple cities and prefectures nearing 40°C (104°F) for several consecutive days.
To compare, the average daytime temperature in August for Hamamatsu between 1898 and 2010 was 31.3°C (88.34°F), the JMA said. Last year, average temperatures in Japan reached the highest level since records began in 1898, and were almost a degree warmer than a typical year, according to the JMA.
"Monday was a scorching hot day (like) I've never experienced, I was wearing a mask outside and drenched in sweat in the heat," said Satoru Shoji, who works at the Hamamatsu tourism office.
On Monday, cities in Nagano, Gifu, Nara, Kochi and Miyazaki prefectures -- covering central and southwestern Japan -- saw temperatures above 39°C (102.2°F).
Residents in the capital Tokyo broiled in 36.5°C weather, and have endured three straight days of temperatures above 35°C. Meanwhile, Osaka posted a high of 37.1°C (98.7°F) on Monday, and the popular tourist town of Kyoto reached 38.7°C (101.6°F)
Australian meteorologists took note recently when not one—but two—vast bands of clouds stretched from the eastern Indian Ocean to Australia, channeling streams of moisture that delivered intense rains to both sides of the continent.
Moisture-transporting atmospheric rivers occur all over the world and regularly hit Australia, but it is rare for two of the rainmakers to hit at once, according to Australia’s Bureau of Meteorology. One of them delivered more than 150 millimeters (6 inches) of rain in less than 24 hours to Western Australia’s Nullabar Coast, a dry area that typically receives 24 millimeters of rain in the whole of August. The second system dropped large volumes of rain on New South Wales.
Atmospheric rivers are often called Northwest Cloud Bands in Australia. The same type of event in the United States is colloquially called the Pineapple Express, because it brings moisture from the tropical Pacific near Hawaii to the U.S. West Coast.
There are some indications that the frequency of atmospheric rivers could be increasing as global climate changes. After searching through 30 years of satellite data (1984-2014) for Northwest Cloud Bands affecting Australia, a team of University of Melbourne researchers concluded that the number of cloud band days had increased by nearly one day per year over the study period.
"If verified, this will be the hottest temperature officially verified since July of 1913," NWS Las Vegas, which owns the automated observation system, said of the reading on Sunday afternoon, emphasizing that it was preliminary.
It will need to undergo a formal review before the record is confirmed because of its significance, NWS said on its Twitter feed, linking to a statement.
Death Valley high temperature record of July 10, 1913
From "Whatts up with That"
*On July 10,Temperature recordings at the Greenland Ranch weather station in Death Valley, California during the intense heat wave of July 1913. This excerpt about the record-breaking heat wave comes from an article posted during January 1922 in the meteorological journal Monthly Weather Review which is still in publication today. Source: NOAA1913, Death Valley, California reached an amazing 134 degrees…the hottest temperature ever reliably recorded in a year with many remarkable weather events*
The high temperature in Death Valley, California on Friday will come close to 120°F, but this is still well short of the all-time record there that occurred way back in 1913. On July 10th, 1913, the weather observer at Greenland Ranch in Death Valley recorded a high temperature of 134°F. One hundred and seven years later, this is still the highest air temperature ever reliably recorded on Earth. In addition to this all-time and worldwide high temperature record, the year of 1913 produced numerous other extreme weather events.
The intense heat of July 1913 in California was not the only extreme heat measured that year in the US. There was a widespread heat wave in June of that same year across the eastern half of the nation which resulted in many readings above 100°F. In fact, NOAA’s official temperature records still cite June 16, 1913 as the hottest ever on a nationwide basis for that particular date. In addition to the excessive heat seen across the US that year, there are newspaper articles from that same time period suggesting high heat may have taken place in others part of the world.
On September 12th, 2012, the WMO officially re-certified the 134 degree reading of July 10th, 1913 at Death Valley, California as the all-time highest air temperature ever recorded on Earth after evidence surfaced suggesting the Libya record of 136°F was based on a reading from a bad thermometer that was placed in the wrong place (near asphalt) and read by an untrained observer
Hottest Day Ever in Australia Confirmed: Bourke 51.7°C, 3rd January 1909
From "Whatts up with That"
The Australian Bureau of Meteorology deleted what was long regarded as the hottest day ever recorded in Australia – Bourke’s 125°F (51.7°C) on the 3rd January 1909. This record* was deleted, falsely claiming that this was likely some sort of ‘observational error’, as no other official weather stations recorded high temperatures on that day.Australian Bureau of Meteorology deleted what was long regarded as the hottest day ever recorded in Australia – Bourke’s 125°F (51.7°C) on the 3rd January 1909. This record* was deleted, falsely claiming that this was likely some sort of ‘observational error’, as no other official weather stations recorded high temperatures on that day.
Photograph of the the relevant page from the observations book, and it shows 123°F was recorded at 9am on the morning of Monday 4th January 1909 – published here for the first time. This was the highest temperature in the previous 24 hours and corroborates what must now be recognised as the hottest day ever recorded in Australia of 51.7°C (125°F) degrees at Bourke on the afternoon of Sunday 3rd January 1909.
photographed by Craig Kelly MP. Note 123F recorded at 9am on 4th January 1909.
There have a lot of complaints about our cloudy weather of the past month--and it has been a bit depressing.
Yes, western Washington typically "enjoys" a cloudy, June gloom this time of the year, as high pressure builds over the eastern Pacific, pushing cloudy marine air up to the Cascade crest.
Has this year been particularly bad? The essential answer: Yes, but not by a lot.
We can start with the total monthly radiation reaching the ground in Seattle at the WSU AgWeather site near the UW, which only goes back to 2012. June 2020 was the darkest June since 2012--eight years. June 2015, when high pressure dominated our region, was far brighter. 2012 was abysmal.
A polar vortex packing bone-chilling temperatures is turning the usually mild Mother's Day weekend into a preview of winter, bringing snow flurries to Manhattan on Saturday and even 10 inches of snow to northern New England.
The powerful stream of cold air, which normally confines itself to the Arctic, slipped southward instead and brought frigid temperatures and un-springlike snow to Canada and the eastern two-thirds of the United States.
The National Weather Service says the cold-air blast will hit the Eastern, Central and Southern U.S. during the weekend, with some snow from the Midwest to the Appalachians.
Some higher elevations in northern New York and New England reported snowfall accumulations Saturday of up to 10 inches, while traces of snow were seen along the coast from Maine to Boston to as far south as Manhattan.
New York City got in on the action early, with about a half-hour of snow early Saturday. That tied the record, set in 1977, for the latest date in spring snow was documented in Central Park, according to the NWS.
Detroit, Pittsburgh and New York City's Central Park also posted records low for the day, according to AccuWeather. Washington, D.C., with an overnight low of 37, smashed a 54-year-old record for the lowest day in May. The nation's capital was also flirting with a new record for the coldest high temperature for the day — 52 degrees — set in 1877
Can Meteorologists Help Epidemiologists with Coronavirus?
From Cliff Mass Weather Blog.
Meteorologists involved in the large U.S. numerical weather prediction community. And perhaps
meteorologists can help epidemiologists and the U.S. government to get a handle on the coronavirus situation.
Now don't take this blog as one uppity weather guy trying to give advice "outside his lane." A published paper in the Journal of Infectious Diseases (2016), said much of the same, with the authors noting the huge similarities in the work meteorologists and epidemiologists do and suggesting that the epidemiological community is roughly 40 years behind the numerical weather prediction enterprise. They observed that both epidemiological and numerical weather prediction models are attempting to simulate complex systems with exponential error growth, and thus have great sensitivity to initial conditions. So perhaps the experience of meteorologists, who spend much of their time thinking about how to improve weather forecasting, may be relevant to the current crisis.
The First Step in Prediction: Describing the Initial State of the System To predict the future you need to know what is happening now. The better you can describe the initial starting point of forecasts, the better the forecast. Meteorologists have spent 3/4 of a century on such work, first with surface observations and balloon-launched radiosondes, and later with radars and satellite observations. Billions have been invested in the weather observing system, which gives us a three-dimensional observational description of atmospheric structure. Big data. And we have learned how to quality control and combine the data with complex data assimilation techniques, with the resulting description of the atmosphere immensely improving our predictions. This work is completed operationally by large, permanent groups such as NOAA and NASA, with large interactions with the research community.
Contrast this to the unfortunate state of epidemiologists predicting the future of the coronavirus.
They have very little data on what is happening now. They don't know who in the population is currently infected or has been infected. They don't even know the percentage of the current population that is infected. Without such information, there is no way epidemiologists can realistically simulate the future of the pandemic. They are trying, of course, but the results have been disappointing.
Meteorologists use complex, full-physics models comprised of equations that predict the future evolution of the atmosphere. Then we apply statistical corrections to make the forecasts even better.
The meteorological community has a long and successful track record in an analogous enterprise, showing the importance of massive data collection to describe the environment you wish to predict, the value of sophisticated and well-tested models to make the prediction, and the necessity to maintain a dedicated governmental group that is responsible for state-of-science prediction. Perhaps this approach should be considered by the infectious disease community. and the experience of the numerical weather prediction community might be useful.
It's Bizarre: March was Colder than January In Seattle
Everything seems topsy turvy and unnatural these days, and there is a meteorological oddity that must be added to the list:
March was cold than January in Seattle this year.
I knew March was a cool one, but it was not until Dr. Joseph Zagrodnik, a talented atmospheric scientist working at WSU's AgWeatherNet organization, pointed in out to me, did I realize how unusual the past month had been.
According to Dr. Zagrodnik, the average temp in March at Sea-Tac Airport was 44.8 degrees F compared to 45.1 F in January.
How unusual is this? Rare, but not unprecedented. March has been cooler than January 8 times in the 126 years we have temperature records in Seattle, with the last time it occurred in 2006.
To appreciate this oddity visually, the graph below shows the numbers of year the March minus January temperatures fell in various bins. On average, March is about 5F warmer than January, but in some extreme years March has been as much as 17F warmer. That would get folks attention. Ten years were close to zero (within .5F of zero) and only a handful (3) were .5 to 1.5F cooler in March.
Another way to appreciate our cool March would be to look at a map of the difference of this year's March temperature from normal (see below). Western Washington was much cooler than normal, with some areas 4-5F cooler than typical values. More normal temperatures east of the Cascade crest.
I know your next question: Why? A good question. It has to do with an unusual weather pattern that has persisted over the North Pacific during the past month, one that includes a ridge of high pressure offshore with persistent cool, northerly flow over the Northwest.
The figure below shows the height (like pressure) anomalies (difference from normal) around 18,000 ft above the surface (500 h Pa pressure). Unusually high heights offshore (red) and lower than normal heights (blue/purple). This is a cold pattern for us, with unusually strong/cold northerly flow over the Northwest coast.
Finally, I wanted to show you an extraordinary picture taken yesterday (Wednesday) around 5:20 PM from the Seattle SpaceNeedle PanoCam. With cold air aloft and great instability, there was a magnificent line of cumulus clouds along the western slopes of the Cascades. Just stunning.
Sangay (Ecuador): (28 Mar) Explosive activity continues. Volcanic Ash Advisory Center (VAAC) Washington warned about a volcanic ash plume that rose up to estimated 22000 ft (6700 m) altitude or flight level 220 and is moving at 10 kts in SW direction.
Scientists recording the first-ever heatwave event in Antarctica over the 2019-20 summer period. Researchers from the Australian Antarctic Program recorded the heat wave at the Casey Research Station — located on the northern part of Bailey Peninsula on the Budd Coast — between January 23 and 26, which falls in the region’s summer season.During the three days, minimum temperatures climbed above zero, and maximum temperatures reached above 7.5 degrees Celsius. On January 24, its highest maximum of 9.2°C was recorded, almost 7°C above Casey’s 30-year mean for the month.
“Heatwaves are classified as three consecutive days with both extreme maximum and minimum temperatures,” University of Wollongong biologist Sharon Robinson explained.
“In the 31-year record for Casey, maximum temperature of 9.2 degrees Celsius is 6.9 degrees Celsius higher than the mean maximum temperature for the station, while the minimum is 0.2 degrees Celsius higher,” Robinson said.
31st March 2020
Messgae from Maximiliano from Thailand :
Hottest T ever of March in THailand 42.9C yesterday and today recorded at Thoen.
Also hottest March ever nationwide as always.
Every month Thailand is setting records heat,never been below average not even a single day of the year.
Heat indexes are expected to rise around 70C next weeks."
On February 6, 2020, weather stations recorded the hottest temperature on record for Antarctica. Thermometers at the Esperanza Base on the northern tip of the Antarctic Peninsula reached 18.3°C (64.9°F)—around the same temperature as Los Angeles that day. The warm spell caused widespread melting on nearby glaciers.
The warm temperatures arrived on February 5 and continued until February 13, 2020. The images above show melting on the ice cap of Eagle Island and were acquired by the Operational Land Imager (OLI) on Landsat 8 on February 4 and February 13, 2020.
The heat is apparent on the map below, which shows temperatures across the Antarctic Peninsula on February 9, 2020. The map was derived from the Goddard Earth Observing System (GEOS) model, and represents air temperatures at 2 meters (about 6.5 feet) above the ground. The darkest red areas are where the model shows temperatures surpassing 10°C (50°F).
Mauri Pelto, a glaciologist at Nichols College observed that during the warming event, around 1.5 square kilometers (0.9 square miles) of snowpack became saturated with meltwater (shown in blue above). According to climate models, Eagle Island experienced peak melt—30 millimeters (1 inch)—on February 6. In total, snowpack on Eagle Island melted 106 millimeters (4 inches) from February 6- February 11. About 20 percent of seasonal snow accumulation in the region melted in this one event on Eagle Island.
“I haven’t seen melt ponds develop this quickly in Antarctica,” said Pelto. “You see these kinds of melt events in Alaska and Greenland, but not usually in Antarctica.” He also used satellite images to detect widespread surface melting nearby on Boydell Glacier.
Pelto noted that such rapid melting is caused by sustained high temperatures significantly above freezing. Such persistent warmth was not typical in Antarctica until the 21st century, but it has become more common in recent years.
The warm temperatures of February 2020 were caused by a combination of meteorological elements. A ridge of high pressure was centered over Cape Horn at the beginning of the month, and it allowed warm temperatures to build. Typically, the peninsula is shielded from warm air masses by the Southern Hemisphere westerlies, a band of strong winds that circle the continent. However, the westerlies were in a weakened state, which allowed the extra-tropical warm air to cross the Southern Ocean and reach the ice sheet. Sea surface temperatures in the area were also higher than average by about 2-3°C.
Dry, warm foehn winds also could have played a part. Foehn winds are strong, gusty winds that cause downslope windstorms on mountains, often bringing warm air with them. In February 2020, westerly winds ran into the Antarctic Peninsula Cordillera. As such winds travel up the mountains, the air typically cools and condenses to form rain or snow clouds. As that water vapor condenses into liquid water or ice, heat is released into the surrounding air. This warm, dry air travels downslope on the other side of the mountains, bringing blasts of heat to parts of the peninsula. The drier air means fewer low-lying clouds and potentially more direct sunlight east of the mountain range.
“Two things that can make a foehn-induced melt event stronger are stronger winds and higher temperatures,” said Rajashree Tri Datta, an atmospheric researcher at NASA’s Goddard Space Flight Center. With warmer air in the surrounding atmosphere and ocean, the conditions were conducive this month for a foehn wind event.
This February heatwave was the third major melt event of the 2019-2020 summer, following warm spells in November 2019 and January 2020. “If you think about this one event in February, it isn’t that significant,” said Pelto. “It’s more significant that these events are coming more frequently.“