Monday, May 12, 2014

South West Monsoon 2014 - update #2 - "Monsoon for Andamans on 17-May-2014"

The feared "El Nino" - South West Monsoon killer !!
As compared to previous El Nino alerts this latest report / alert suggests that this year's El Nino is expected to be a weak one.
Here's the report published by BOM-Australia...

The tropical Pacific Ocean has warmed steadily in recent months, with large warm anomalies in the ocean sub-surface (5-day values up to +6 °C) and increasingly warm sea surface temperatures. Climate models surveyed by the Bureau suggest El Niño development is possible as early as July. These factors indicate that while El Niño in 2014 cannot be guaranteed, the likelihood of an event developing remains at least 70% and we are at El Niño ALERT level.
As far as latest analysis, the Indian Ocean Dipole (IOD) is presently in Neutral state and expects it to be Neutral till Dec-2014.

As per the above report, the El Nino may not haunt this year's Monsoon !

Central, N-E India Heat LOW
As of today, the LOW pressure generated by HEAT over N-W, Central, East India is around 1002mb and this is slightly high at this time of year. It should be around 1000mb.
Even though the W.D systems traversing N,N-W India has reduced, the consistent heating has not picked up.

North-South inland low-level trough (or) Line of Wind Discontinuity 
After the LOW pressure crossing the S-central Peninsula, the N-S low-level trough from N Bengal to S Tamilnadu is expected to be back in position on 13-May.

Sea Surface Temperature(SST) over Bay and Arabian sea
SST over most of Bay is around 30 C, meanwhile there's almost reduction in SST seen along Somali seas, this is sign that less cross equatorial winds are reaching Somali coast. Please note, that around 25-May, the SST along Somali coast should be around 20 C.

From 5-May to 10-May, the Bay LOW materialized somewhat in the form 91B, which formed along Gulf Mannar and then moved to S-E Arabian sea and pushed inland thru Coastal Karnataka and then died along S,central Chatisgarh.
Now, GFS predicts a weak low-level circulation on 15 / 16-May over S-central Bay, Which will act as a driving engine for the entry of S-W Monsoon winds into S,S-E Bay into S,central Andaman Islands. On 18/19-May, the circulation may strengthen and slowly drift N-N-E into Bay.
Monsoon is expected to break into S,central Andamans on 17-May-2014.

Mascarene HIGH pressure system and Cross Equatorial Winds

At present the pressure over the Mascarene high pressure system over South Indian Ocean is around 1020mb, and in fact the system is pushed slightly to East by a LOW (which is located S-W to the High). In coming days, this high pressure system should come near to Madagascar Islands and pressure should be around 1030mb before 20-May. This will help the speedy push of winds towards Somali coast and start to cross into S-W Arabian sea.
Not a good sign at this time ! Arabian sea wing of Monsoon may get delayed !

Present, W.D low-level circulation is expected to push into S-W Rajasthan in next 12hrs and drift E-N-E ... 
The mid-level W.D trough and circulation is expected to come close to N,N-W India on 13-May and drift East ... 

On 13-May, W.D, scattered moderate rain expected over S,S-W Kashmir, Himachal, into Uttarakhand, Punjab, N,N-E Rajasthan, Haryana and #Delhi
Some showers also expected over W Uttarpradesh, E,S-W Rajasthan as well on Tuesday.
At very-low-levels (925hpa).. a circulation is expected over N Bengal and its trough is expected down South upto S Tamilnadu thru N-W Andhra
This circulation and South dipping trough is expected to persist during next 2 days ... it'll drift slightly to East along to S-E coast

Tomorrow again T showers expected over S,S-W Tamilnadu and over S, south W-ghats of Kerala... 
Morning showers along S Kerala coast and S tip Tamilnadu coast is expected tomorrow (13-May) morning as well !
Tomorrow, isolated T showers also for N,N-E Madhyapradesh, S,central Uttarpradesh and S Bengal.
NO reduction in scattered T showers expected over N,central zones of N-E states on 13,14,15-May.
#Chennai - Temperature Today...
Nungambakkam = 38.6 C
Airport = 39.3 C

#Chennai - Expected to continue with around 39 C and may touch 40 C before 16/17-May.

Tirunelveli - T showers !!

Tirunelveli - 1:55pm, hot and humid. Thunder cell seen over N-E. #weather

Tirunelveli - 3:47pm, thunder shower just started.

91B Life Cycle from 05th -10th/11th May 2014