Sunday, November 23, 2008

The easterly wave from the bay has produced good amounts of rain in the southern peninsula of India in the last 5/6 days, and as expected, the embedded low, still holds on to a forecast by models for the formation of a low in the southern bay around the 25th.The rains will continue till the approaching system pours more rain in the regions it covers.

The cloudiness in the south and prevailing south-easterlies,has resulted in a "heat wave in November" along the west coast of India, especially the northern parts including Mumbai.Mumbai, is unusually warm and hot. The highs in Mumbai during the last two days is hovering around 36c.while, for the information, the highest ever in November for Mumbai is 37.4c Ratnagiri, at 37c on the 22nd., was the hottest spot in Asia !!Meanwhile, normal hotspots like Dubai was 31c and other spots in the gulf were around 31-33c. THe IMD map above shows the heat wave along the northern west coast.

Tuesday, November 18, 2008

Tropical Cyclone 05B, or Khai Muk, moved inland through A.P. and quickly moved westwards towards South Maharashtra, and, as the IMD streamline image above shows, has now entered the Arabian Sea as a low pressure. But not much should be expected from this weak system now, as it will dissolve in the "not so warm" waters of the sea.

Maharashtra did get its expected share of scattered rains. Nanded got 10mms and Mahableshwar recieved 15mms,suddenly cooling the hill station down to a max. of 18.6c, while several other towns in Maratwada and south Maharashtra, including Goa and Konkan had rains between 3-8mms.Mimbai had a light drizzle on Tuesday night.

Now, due to the sudden incursion of moisture, the sporadic rains, though weak, will continue in interior Maharashtra till Friday, after which, the dry spell of winter will resume in the region.

A strongish easterly wave off the T.N. coast (seen in the steamline map) is expected to bring fairly good rains in coastal and inland T.N., south coastal A.P.from the 19th. The E.Wave will have a low embedded in it, which should increase the easterly current (and rains) around the 20th.
Some "monsoon like " conditions will be seen in the south now. Contiunity of fairly good rains are expected in these regions till the 25th.

Tropical depression Noul hit southeastern Vietnam on Monday, bringing heavy rains and flooding, in the tenth storm to hit the country this year.The storm, which was downgraded from a tropical cyclone as it made landfall near the coastal city of Nha Trang.
Noul has been weakening rapidly over land during the past day, and is forecast to dissipate fully over Cambodia later today, before emerging in the Gulf of Thailand.

Around the 25th.ECMRWF has predicted the formation of a depression in south bay. This is the maturing of the embedded low in the E.Wave.It is forecasted the depression can strengthen into a deep depression, or even a cyclone by the 27th.

Meanwhile, winter has made its mark in the northern sub continent. The minimum temperatures have gone down to -10c in Leh, and -8c in Quetta, with several stations in north Kashmir seeing -2c to -5c.The plains of Punjab are now in 8c range.
With another W.D. approaching the extreme north,more rain/snow can be expected in the higher reaches in a day or two.

Saturday, November 15, 2008

Writing after 7 days, I was waiting for the low I mentioned in my prevoius blog, to appear. Well, it has certainly "appeared"' and swiftly swung into action, and has already become Tropical Cyclone 05B. As on 14th. night, TC05B was at 225NM north-eastof Chennai. Central core pressure is at 989mb,and expected to strenghten further.Now,it will steer clear of the ridge,to cross the Andhra coast near Vijaywada by the night of the 15th.Naturally, very heavy rains and very squally weather is to be expected off the Andhra coast today and tomorrow. The effect on the north Tamil Nadu coast will also be felt in the form of heavy rains in Chennai on the 15th./16th.
Interior A.P. will be affected the most,and some coastal towns in A.P.expected to record upto 200mms of rain in 24hrs.

Now,as the system moves inland, some interesting rainfall pattern is expected. After the system has covered the whole of A.P. with rains, Marathwada and north interior Karnatak can get some rains by the 17th. South Maharashtra, including Pune and Mahableshwar, can recieve rains around the 17th./18th and the "northern" ghats, meaning Lonavla, can recieve rains on the 18th. But the system will fizzle out quickly after moving inland, hence the Maharashtra rains will last only for a day or two.Mumbai has a 50-50 chance of some thunder cloud drifting over on the 18th.

In the northern regions, the W.D.mentioned has poured good rains/snow in Kashmir, and northern areas of Pakistan. Srinagar had 35mms of its first snow this season, with the day temperature not rising above 1.6c on the 14th.And also, in its moving away, a cold front has covered the "rear' of the W.D. Lows of -8 to -9c have been recorded in western regions of Pakistan on 14th.
Hence, I certainly expect a cold wave over Kashmir, H.P., Punjab, north Rajasthan,Delhi and Haryana after the 16th.In Delhi, minimum temperatures can go down to 10c, and places in Punjab will see 8c in the next few nights.

Friday, November 07, 2008

No rains period continues in the entire sub continent region. The reason is a dominant "high" in the 500-700hpa heights, stagnant over the north-west India areas. Resultantly, there is above normal warmth over the region, with places in Sindh and rajasthan recording upto 37c, in 2nd. week of November !
Nights are just about getting a bit cool, with the plains in Pakistan recording lows in the 8-10c range, and the northern plains of India recording between 10-12c, still, above normal..However, the southern half of India remains around normal. Srinagar reached 1.9c yesterday(6th.) and Leh was at -5c.Both are around normal.

Clearly seen in the IMD maps above.

We now have to look out for: - The "high" to shift eastwards, toenable some rain to commence in the south.
- The WD to move eastwards along the Kashmir region to produce some rain/snow over the northern areas.
- To wiat for the formation of a low, expected middle of next week, in the bay. Could later become a depression.

Sunday, November 02, 2008

The temperatures in the sub continent show no signs of the winter lows. The days and nights are still above the normal. Another WD is awaited for the actual winter to arrive in the region. The IMD maps above show the extent of the above normal temperatures.

Meanwhile the cyclonic storm "Rashmi" weakened and after passing through the north-eastern states of India, crossed into Tibet region.A massive snowstorm followed.
The snowstorm event was attributed to "Rashmi" which developed over the Bay of Bengal and drifted north. Heavy rain associated with the cyclone quickly turned into heavy snow across the Tibetan region as it collided with a cold air mass. Although heavy snow is not an uncommon event in Tibet, a snowstorm this severe was fairly unusual this early in the season.
Heavy snow fell for more than 36 consecutive hours earlier in the week averaging snow coverage of 1.5 meters, with drifts up to three meters in places. Many people were either frozen to death or crushed by buildings which collapsed from the sheer weight of the snow.

Meanwhile,there is a weak sign of an easterly wave bringing some rain in TN and south AP from the 5th.The rains are expected in TN for about 3/4 days, before drying out again. ECMRWF expects the next low in the bat around the 16th. Not much rain before that.


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