Sunday, March 30, 2008

The temperatures in the northern regions of the sub continent continue to be around 2-4c above the normal. Nawabshah in Pakistan at 43c, 2 days ago and Akola at 41c are the highs of the region. But the dipping low aloft from the Afghanistan region will bring in 2 W.D.s in the first week of April, but rain maybe restricted to the northern areas only.

By the 15th. April, normally the pre monsoon stage must set in, with the preparation for the formation of the monsoon low over the northern regions of India begining to start. With the MSL in the region today at 1006mb, and the W.D.s still hovering around the plains of the north, the initial formation of the seasonal low could go into the 3rd. week of April. May not be a cause of worry for the monsoon if the W.D.s are pushed northwards after the first week and a heat wave with temperatures about 4-5c above normal occurs.

Even the bay region today is still below normal temperature wise. Central bay was today at 25c, and the rest of the areas around 27-29c, while this is a bit on the lower side, and may delay the formation of the first pre monsoon low in the bay, which normally appears by the 15th., the heating up of the waters will be observed in the next few weeks.

Monday, March 24, 2008

The entire regions of Tamil Nadu and Kerala have recieved rainfall amounts far exceeding thier normal amounts for the month of march. Manglore and Tvm have recieved their highest ever 24 hr. rain for March as well as the highest ever total for the month. There are a few more to add to the list with highest rainfall. Many of the stations in the 2 states have rain exceeding upto 1000% of their normal amounts.

As a result, the days have become cooler in the region, and the north-south divide in the temperature anomoly is seen in the map alongside. The overall average March temperature will make interesting reading, as the March temperature along the east coast is one of the parameters of the monsoon forecast model.

However, I notice a low, maybe insignificant, but showing over the regions of north Maharashtra/Gujarat today (IMD streamline shown). Should fizzle out in a day or two, as a significant low at the 500 hpa. level approaches the north-west areas of the country through Pakistan. Should bring fair amount of rain to northwest India and the hills of north India from the 26th.

Rains in Tamil Nadu/Kerala are bound to taper off with the advent of this W.D., but, some models in their GFS forecast another easterly wave approaching the south India coast by the 31st. March. , This should now be observed for the quantum of rain after the experiance of the previous wave.

This easterly repeat is due to the persistent positive SOI. The 30-day Southern Oscillation Index [SOI] to 15 March was +19, with contributing pressure anomalies of -0.2hPa at Darwin and +3.5 at Tahiti. The official monthly SOI for February was +21.

If the SOI remains at substantial positive levels, the rain patterns of south India will show much variations again in the coming months. Convective waves forming around the equator around the Indonesia regions will continue, as a result, and the easterly rain belts travel westwards.

Saturday, March 22, 2008

The much "hyped" about "well marked low" in the Arabian Sea has dissipated as per the JTWC report of 1800 hrs. on 22nd. Though in its course it has poured tremendous amounts of "record" rains throughout Tamil Nadu and Kerala, it did not intensify as a "first timer" depression in the Arabian Sea. During the last few days rainfall figures in Kerala and Tamil Nadu have been double or triple the normal weekly amounts. And the southern states of Tamil Nadu, Kerala, Karnataka and A.P. have been kept cool and pleasant, as against the rising summer heat normally expected at this time. Days have been 6-9c below the normal in most of the cities in the southern peninsular.
From here, the south should get the respite it needs from the rains. Rains will lessen almost immidietly from Kerala and Tamil Nadu, and shift to A.P. But only to last a day or two there. The south can then ''look forward" to the normal summer rise in day temperatures.
A deep low aloft is expected in the northwest region of India from the 25th. It may carry a W.D. with it and bring some rains to the north and northwest of India from the 25th. And a general drop in day temperatures of 2/3c can be expected here from the 25th. for a few days at least.

Friday, March 21, 2008

Coming into the Arabian Sea as an emdedded "upper air circulation" in an easterly wave, the low pressure system is now, as on 21st., firm over the south east sea off the Kerala coast at 8.6N. The system has been pouring some heavy rain over the Kerala and Karnatak coasts since the night of 20th. Earlier along its path, as an easterly wave, there were unusually heavy to very heavy rains in Tamil Nadu. Kodai.'sMarch has been the wettest ever, with the month's total already at 359 mm, and the previous record of the month was 297 mms. (1947).

This low, if it develops into a depression, it may be the first on record for a very long time in the month of March (no record of any in last 40 yrs. as per my study), in the Arabian Sea.

However, Vinson Kurien, Weather expert from the "Hindu" group, has mentioned and pointed out a very valid and interesting fact. According to his study, since much of the rain is over the Arabian Sea, it may cool down the southern sea waters a bit too much and may hamper the cross equatorial monsoon flow later. As of today, Vinson is correct. The sea temperatures off the Konkan coast is comparitvely hugher than the temperatures off the Karnatak and Kerala coasts and is very distinct in the adjoining image. Also, the sea temperature anomoly this year is far too much on the cooler side, in the central Arabian Sea, as compared to last year.The maps below show this . Also for the record, the anomoly in 2006, the year the monsoon hit Kerala by 26th May, the sea temperature anomoly was more on the +ve side, on the same day that year.

But now, I feel with the formation of a "sudden heat low" of 1002 mb. over central India (south Rajasthan, M.P.), the Arabian Sea "low" may, without intensifying further, by attraction towards the central low, cross the Karnatak coast in a day or two.

I feel, it may be a bit too early to estimate sea temperatures for the monsoon performance yet, and we may still observe the movement of the system across the sea waters to study its thermal effects.

Tuesday, March 18, 2008

On the 17th. March, I observe the first 40 c has been recorded at Akola (Vidarbh), and again at Baroda on the 18th., Exactly as anticipated in the last blog. But, today (18th.), the heat has spread more than expected all over north and central India, with most places recording temperatures 7 c above normal. New Delhi and Hissar at 38c were 7c above and many places were 6c above normal. In IMD terms, temperatures above 6c more than normal amounts to a "heat wave". The maximum temperature map of 18th. shows the temperatures of 37/38c spreading from Rajasthan through central India eastwards.

Down south, and "upper air circulation" has formed over the south east Arabian Sea. This may descend and form a low pressure in the same region, as the easterly flow is strong enough to pump in sufficient moisture (IMD map below).

Most international models forecast rain in extreme south to continue till the 20th., and the rain belt gradually moving north towards Maharashtra through Karnatak 19th. onwards.

Models predict rain (should be light) in Mumbai by Sunday night/Monday.
If the moisture surge is strong enough to push the rain further north into central India from Mahrashtra, it should cool the northern/central regions by next week, and wipe out the heat wave.

Sunday, March 16, 2008

Something out of my usual topic, but a very interesting picture I came across and thought I must put it up:

This rare and meteorologically interesting image was taken while the International Space Station was located over western Africa near the Senegal-Mali border, showing a fully formed anvil cloud with numerous smaller cumulonimbus towers rising near it. The high energy levels of these storm systems typically make them hazardous due to associated heavy precipitation, lightning, high wind speeds and possible tornadoes.

Appearing almost as a mushroom cap, the anvil cloud was actually at the highest level that moisture lifted by the heat of solar radiation could have reached given the meteorological conditions on 5th.February in the tropics.

Another important weather event worth mentioning is the Adeleide heat wave.

Unusually high temperatures continued to scorch the southern Australian city, setting a record for the longest lasting heatwave to affect any major Australian city.On the 12th., as afternoon temperatures peaked at 35.1C (95.2F), a new record was broken as Adelaide reached its 11th consecutive day. According to The Bureau of Meteorology, the length of this heatwave has surpassed the previous record of 10 days above 35C (95F) which was recorded in Perth in February 1988.

The highly unseasonable autumn heatwave across Adelaide has been caused by a strong high pressure system which has brought a steady northerly flow of hot air from the central Australian deserts.Acoording to the BoM, the heatwave is expected to continue into the start of next week as high pressure dominates southern and eastern Australia. Also, rain and a low pressure trough is expected to hit the north Australian region in the second half of March, according to BoM. That means , the South Indian Ocean region is still far from developing a "high", and the ICTZ is hovering around N. Australia as acyclone may still form there next week.

I make a mention of this as Australian regional pressure and weather as this is the forerunner for the sub continent monsoon. But, it is still too early to watch this region. The time to start observing the sea pressure west of Australia ,and the rain pattern in the north of Aust. is from the first week of April.

In the northern sub continent, the heat has started building up, after a brief respite. The first 40c was recorded at Nawabshah (Pakistan). Elsewhere, in the north and west/central areas, the heat will slowly increase from the 17th. and 40c is expected in Gujarat/Vidharbh by the 18th.(almost on normal time).

But down south, the easterly wave has produced some unexpectedly heavy rains. Rainfall ranging from 9- 19cms/day has been recorded in the last few days. The page at shows the huge excess amounts of rain in the region.

Almost all models show the rains continuing all over the south peninsular upto the 20th. Subsequently a low pressure is predicted to emerge in the Arabian Sea around the 18th. off the Kerala coast. It has to be now watched.

Monday, March 10, 2008

As discussed in the last blog, with the advent of a weak W.D., the maximum day temperatures over India and Pakistan have come down and now are at a level of about 2/3 c above normal. The IMD map shows this clearly. The day temperatures in the northern regions will fall to normal levels by the 11/12/13th. After the passing of the W.D., the temperatures in the north,central,Vidharbh and Gujarat regions should rise substantially from the 15th.

Contrary to this, the maps of February,below, shows a much cooler regime all over the mid east and Sub continent.

Also, the forecast for rain from this system also remains consistent, rain over the hills and Kashmir and H.P., but not much over the plains of northern India. A burst of clouds from the Arabian Sea towards the west coast and central India is seen today( Monday), as a result of a secondary low over Rajasthan. But this is expected to fizzle out in a day.
However, the easterly wave approaching the south has become a bit sluggish. This is due to a lower level "distortion" of winds in the interior south peninsular. But it will push rains into the interiors of the southern tip, and then gradually move along the coast as anticipated. To summarise, there should be rains in south TamilNadu from 11th., central and coastal TamilNadu on the 11/12th. and as the rain belt moves north-east rains along the northern T.N. coast and A.P,. coast from the 13th.

Wednesday, March 05, 2008

Well, its a predicted heat wave in north-west India. With temperatures as much as 7 c above normal in Rajasthan, its a "heat wave" in meteorological terms. Map shows the hot "tongue" creeping in from the west. The heat prevails over Delhi, north M.P. and parts of Gujarat and Maharshtra too, with Akola hottest in the country (maybe) at 38.6c.

With the advent of a mild W.D., the heat will relent from Thursday. Immiedietly, the day temperatures will drop all over north by at least 3-4 c, bringing it too slightly "above normal" levels, and bring a cooling in comparison to the sudden upswing. The W.D.may not rain much below the hills of the north due to the effect of a stable ridge aloft.

A deep "vortex" can develop over north Sri Lanka by the 10th. This should bring sudden ,maybe heavy, rains to south and coastal Tamil Nadu from the 11th. As the vortex is deep, the rains may hang on for a couple of days, though restricted to the south and coastal regions of the state. The then formed "UAC" may move north-east along the east coast, and bring some rains alongwith from the 12/13th. May not move or produce precpitation inland due to the steering effect of a strong ridge aloft in the north.

An unusual fog enveloped Mumbai in the early hours of the morning on the 5th.An occurance due to low level condensation, the fog lasted for about 2 hrs. after sunrise, and was thick enough to restrict visibility to 50 feet. I mention this, as actual "sea breeze condensation ground level fog due to cooling" is very rare in Mumbai, and the last recorded fog of this intensity in the city was 35 years ago.

Sunday, March 02, 2008

This blog is in continuation of my blog of 23rd.Feb on the "Global Cooling".According to the latest tabulations, this winter has been one of the coldest in 100 years in many areas of the world and it is showing up in the world's average temperature.
Now, evidence has been supplanted by hard scientific fact. All four major global temperature tracking outlets (Hadley, NASA's GISS, UAH, RSS) have released updated data. All show that over the past year, global temperatures have dropped.
Source: Global ∆T °C: HadCRUT - 0.595, GISS - 0.750, UAH - 0.588, RSS - 0.629
Average: - 0.6405°C (see graph).
There was a dramatic decline in the earth's temperature since last year. I am still perplexed as to why this has not been picked up in major media outlets. Also, there is no mention of this in any major press stories. A record amount of sea ice in the Antarctic, and this sea ice story was also one that was ignored by nearly every media outlet last summer because they were focusing on the record low amount of ice in the arctic (north pole).
The cold waves were certainly was not even remotely predicted by any of the global climate models that the IPCC uses to assess future climate change.
But, why has this winter been so cold? Besides potential large scale effects such as changes in the sun or the earth's orbit which I am not well informed, the two things I can point to are La Nina and a record amount of sea ice in the Antarctic. But he year could still turn out warm of course, because we have only been through 2 months. But, if the cooler trend continues it will force many "Global Warming" theorists to re-think on their theories. And it makes you wonder about the "Global Warming" movement in general, and climatologists must head back to the forecasting computers and figure out what major piece of the climate puzzle was unaccounted for, that caused such a severe error in future projections.
Global Warming theories have always puzzled me. If there are more hurricanes/cyclones, it is because of Global Warming (GW). If there are less hurricanes, it is because of GW. If there is more rain, it is because of GW. If there is more drought, it is because of GW. If it gets really hot, it is because of GW. If it gets really cold, it is because of GW. It will interest me to see how everyone reacts to a cooler trend. Will we continue to see GW scare stories even in the face of a cooler planet? I'll be sure to keep track of it.
(Thanks Justin for genuine good inputs).

Saturday, March 01, 2008

One of the points forecasted in my last blog was the "substantial rise in temperatures".
Well, its proving to be true, but more than expected.
Summer heat poured down on north India on Friday/ Saturday, pushing back to distant memory the need for woollens only a couple days earlier. It is spring by the Indian calendar now in north India. But it sure didn’t feel like it for the second day in succession, as residents in all of the north and central India scrambled for shade and switched on their fans. For the second day in succession, Saturday saw the high temperature mark around 30-35 degrees Celsius, nearly five degrees above normal. The minimum the night before had been 11c in most of the region, so nights are a bit pleasant still. (Its officially summer" from 1st>march in "non spring" areas like Maharashtra and Gujarat).

The IMD has predicted a further 3-4 degree rise in maximum temperatures all over north India Sunday and Monday.
The northern/central plains weren’t the only place feeling the heat. In Kashmir, Srinagar saw Saturday’s high of 18 degrees, 9 above normal, just a week after residents had been in the middle of a cold wave with heavy snowfall.
Situation of "hot weather '' might continue in north and central regions for another 4/5 days. West coast should cool down by about 3 c from the highs of 37 c.