BB-2 now a depression, with 996 hpa core pressure and at 21.1 N and 89.5E, 200 kms SE of Kolkata.Winds at 25 knts and intense clouding from 13N Northwards and in the 82E to 94E region in the SW of centre.
Due to anti-cyclone in the NE, it will cross the Bangladesh coast after moving N/NE from current position, and will remain as depression on crossing.
High tides/waves and gusting winds of 35 knts on Bangladesh and adjoining W.Bengal coast.
AS-1 is situated at 18.5N and 57.5E, just off the South Oman coastline, about 100 kms away from shore, slight shifting westwards since last 12 hrs.
Position as on Tuesday Night:
1. AS-1 is now crossing land at 18.7N and is at 58E...as a Low. Muscat will be cloudy with light rains on Wednesday 29th. Drop in day temperatures in Muscat.
Meanwhile, the West coast off shore trough weakly prevails near S.Konkan and Southwards till Kerala. On Tuesday, South Konkan, Goa and coastal Karnataka recieved thunder showers in varying amounts.
AS-1 crossing will clear the way for the "half formed" west coast trough to extend up into North Konkan on Wednesday.
Mumbai and outer townships should see thunder heads forming on Wednesday 29th and Thursday 30th, with possibility of showers in outer townships in the evening.
On Wednesday and Thursday, clouding drifting in to Mumbai could bring some rain in some parts of Mumbai.
As mentioned, the off shore trough is weak, and will fizzle out from Thursday 30th. As the LWD regains its "lost" position back into the Interiors of the Peninsula, from Thursday/Friday we see thunder showers, vigorously coming in to the interior Mah and Karnataka regions. Madhya Mah and Marathwada regions get thunder showers on Thursday 30th/Friday 31st, while Vidarbha remains dry and hot.
2. BB-2 is stationary at 20.3N and 89.6E. Core pressure estimated at 998 mb and winds at 25 knts..already a well marked low, as mentioned yesterday, deepening further and could cross as a depression.Major clouding in West and SW quadrant while crossing. Intermittent rains for Kolkata on Wednesday and Thursday.
As BB-2 crosses, the LWD goes inland into the peninsula region, and the rainfall shifts to the interiors.
Chennai could get some relief from the sea breeze as the Easterlies would get stronger from Friday 31st.
3. Northern India, NWI and Pakistan remain dry next 3 days. But we see a rise of 2/3c in the Northern plains and NWI from Friday onwards.
Rise in day temperatures in Balochistan and Sindh from Thursday, possibly reaching 49/50c again.
Shall put up a separate forecast for Friday/Saturday and Sunday by Thursday evening.
Posted on Tuesday Morning:
Arabian Sea UAC descends to sea level and as "AS-1" is located at 18N and 60E. At 1006 mb, expected to move into Oman .
BB-2 lies stationary at 21N and 89E, at estimated pressure of 1000 mb. Just South of India/Bangladesh border, expected to move NE.
The East coast off shore trough has drifted Eastwards a bit under the effect of BB-2. Thunder shower likely for Chennai or vicinity on Tuesday.
The West coast off shore trough could get re organised by Wednesday as the AS-1 crosses land.
Posted 28 May 00:30 am IST
What Vagaries had forecasted till Monday 27th ( In last post on 24th May):
1. "An trough off the west coast of India may form and result in thunders shower in and around Mumbai, S.Konkan, Goa and coastal Karnataka Sunday26th/Monday 27th.
Pre- Monsoon showers expected around Mumbai vicinity on 26th may/27th May. Pre-Monsoon thunder showers increase after 3rd/4th June."
And to what extent it happened :
1. A weak off shore trough formed off the coast from South Konkan downwards till Kerala. Resulting in thundershowers in South Konkan, Goa, and coastal Karnataka and Kerala. Kearala and coastal Karnataka are receiving Thunder showers from Saturday 24th, while South Konkan and Goa received on Sunday 25th and Monday 27th, specially heavier on Monday27th.
The UAC in Western Arabian Sea could be the spoil sport for North Konkan. Mid Sea winds from 15N got diverted and blew North wards from that line and re-curved clockwise into the UAC around the Oman coast.
I expect the UAC to descend and form a low, and and cross into Oman. Things will get back to routine from Wednesday, and winds all along the coast will become SW.
This will extend the off shore trough along N.Konkan and bring pre monsoon showers there.
BB-2 in the Bay has formed South of Bangladesh, with strong clouding in the SW and S quadrant. Expected to deepen to 996 mb ( depression) and cross the Bangladesh coast byTues/Wed 29th. By Wednesday 29th, M-3 will have pulled and elongated the seasonal low right upto UP.
This will result in a LWD running from Eastern Nepal thru into Bihar, Bengal and the Bay.
Clouding will be extensive along the LWD.
Heavy rains are likely in Bihar, W.Bengal and Bangladesh on Tues/Wednesday and Thursday.
Would expect 55-60 mms in Kolkata on Thursday.