Sunday, August 22, 2010

91B has come and gone !
Remnants of an erstwhile low, presently at 1004 mb in the southern Bay, hangs around, embedded in an off shore trough line along the Eastern coast south of A.P. With clouding along the trough, we have seen rains in T.N. in the last couple of days.In fact very good rains all over the state have raised hopes , after a weak SWM. Almost reminding the state of the NEM.
Bangalore was drenched with good rains from Thursday/Friday. After rains on Sunday evening, the rains may decrease in the city.

I would expect this low, to deepen and sort of re-form in the same region by 22nd/23rd. But would not expect very heavy rains at this stage.

Now, almost all models indicate the low to linger in the same region, in the sea, till 26th. Around that date, it may enter inland, as a 1000 mb low.
Where ? Normally I would say the A.P.coast. But, as a W.D. (I name it 25W), is crossing the northern region, we could expect the low to be pulled away from the east coast, and move Northerly, and then maybe cross near the Orissa/Bengal coast.
T.N. rains wll decrease , and the persisting low, will result in cloudy weather, but lesser rains in the interiors of the states of T.N. and Karnataka, next 3 days. Thence, all depends on the course of the low.But, I would expect precipitation in pockets to continue in the southern peninsula throughout next week.
See a small vortex, inland forming north of Bangalore on Monday/Tuesday. Maybe some rain in Bangalore on Monday night/early Tuesday.

The same 25W is sure to inter act with the axis, by then in a firm position along the Himalayan foothills, and produce heavy rains from H.P.thru Utteranchal and west U.P. and Nepal. We can expect very heavy downpours along the hills as the axix itself is also at a pressure of 1000 mb.The western end of the axis is saddled in Balochistan, at 998 mb.and will remain firm till the TD off the Vietnam coast survives. Indicating no signs of the monsoon withdrawal from there as yet.
This coming week, more rains for Delhi area after the 25th.

The western coast off shore trough remains weak next week. Normal rains of upto 10/15 mms per day could be expected.

Mumbai: Another few days of less rain.
Monday: Partly cloudy, with sunny intervals. A couple of brief heavy showers.
Tuesday:Partly cloudy, with sunny intervals. A couple of brief heavy showers, especially in the night.
Wednesday: Cloudy with some showers. Stuffy at night.
All days rains will measure upto 10/12 mms per day.

Monday: Cloudy day, with drizzle. More Rain at night, with thunder. Rain upto 15 mms.
Tuesday: Rains in the a.m. Later cloudy and cool. Rains measuring upto 10 mms mms.
Wednesday: Cloudy with drizzle. rains will measure about 5 mms.

All India Rainfall Toppers From 1st. Jan - 21st.August 2010: (From Pradeep)

Cherrapunji (Meghalaya) - 1140 cm (Annual around 1100)
Agumbe (Karnataka) - 488 cm (Annual over 750)
Gaganbawada (Maharashtra) - 432 cm (Annual over 600)
Shirali (Karnataka) - 351 cm (Annual over 400)
Coochbehar (West Bengal) - 342 cm (Annual around 350)
Passighat (Arunachal Pradesh) - 331 cm (Annual around 450)
Mahabaleshwar (Maharashtra) - 321 cm (Annual over 600)
Silchar (Assam) - 308 cm (Annual around 350)
Honavar (Karnataka) - 307 (Annual over 350)
Ratnagiri (Maharashtra) - 307 cm (Annual around 300)
Buxa (West Bengal) - 302 cm (Annual around 550)
Piravom (Kerala) - 302 cm (Annual around ??)
North Lakhimpur (Assam) - 298 cm (Annual around 350)
Panambur (Karnataka) - 293 cm (Annual over 350)
Mangalore AP (Karnataka) - 292 cm (Annual around 400)
Bhagamandala (Karnataka) - 291 cm (Annual over 600)
Vadakara (Kerala) - 287 cm (Annual around ??)
Karwar (Karnataka) - 282 cm (Annual around 400)
Gangtok (Sikkim) - 280 cm (Annual over 350)
Panjim (Goa) - 273 cm (Annual around 300)
Jalpaiguri (West Bengal) - 268 cm (Annual around 350)
Kottigehara (Karnataka) - 263 cm (Annual around ??)
Harnai (Maharashtra) - 263 cm (Annual around 250)
Mumbai Colaba (Maharashtra) - 263 cm (Annual around 200)
Mumbai Santa Cruz (Maharashtra) - 262 cm (Annual around 250)
Peermade (Kerala) - 256 cm (Annual around 500)
Chinnakallar (Tamilnadu) - 253 cm (Annual around 500)
Kannur (Kerala) - 248cm ( Annual around ??)
Itanagar (Arunachal Pradesh) - 245 cm (Annual around 350)
Matheran (Maharashtra) - 232 cm (Annual around 550)
Kozhikode (Kerala) - 232cm ( Annual around ??)
Kochi AP (Kerala) - 229cm ( Annual around ??)
Dibrugarh (Assam) - 228 cm (Annual around 300)
Valparai (Tamilnadu) - 222 cm (Annual around 350)
Dahanu (Mah.) - 215 cm (Annual around 250)
Kottayam (Kerala) - 206cm ( Annual around ??)
Devala (Tamilnadu) - 202 cm (Annual over 400)


nt said...

The IMD still maintains the formation of a low in the South Central Bay as of today morning's bulletin.

Also, the GFS 500 MB Vorticity images seem to suggest vortices (the ubiquitous ones!!) around Mumbai from Wednesday lingering till Friday. Although having said that, these images change every 12 hours (and sometimes completely)

BTW you have mentioned Dahanu in Goa in the rain statistics list, it should be Maharashtra

Rajesh said...

Thanks for the error reg. Dahanu. Corrected.
Reg. low, I mentioned it could re-form by 22/23.
nt, many models show diversive views. To estimate a rainfall forecast, what I do is go thru them, mind well we have to see the 925,850,700,500 and at times the 200 hpa charts. Also must check the synoptic situation, as sometimes formations of low are "in situ".
Need to see the axis for tracking the direction and the winds alongwith to see the depth.
I put forward my own estimate on personal assumptions of combinations and experiances.You may notice from previous blogs,I am totally "against the stream".i.e.totally against the general views mentioned by agencies or models.
May notbe always correct though.

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