SPECIAL WEATHER UPDATE | DATE: 04 DEC 2022 | TIME: 10:30PM BST (+6 GMT) | SUB: TROPICAL DEVELOPMENT | PERIOD: 5TH-8TH DEC 2022
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Under the influence of a Disturbance (INVEST 96B), A Low Pressure Area could form over South-East Bay of Bengal by tomorrow (5th Dec 2022).
BWOT dynamic analysis suggests that the potential system could intensify into a Well Marked LPA by 5-6 December and further intensify into a Depression/Deep Depression or even a Cyclonic Storm by 6-8th December while moving through South West Bay of Bengal.
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▪️Global Models suggest a Low Pressure Area development over SE BOB adjoining South Andaman Sea by tomorrow. And possible intensification up to a Cyclonic Storm between 6-8th December over South West Bay of Bengal & cross coasts between Tamil Nadu – South Andhra Pradesh around 9-10th Dec 2022. While few of them also suggest intensification up to only a Depression within the given period.
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•DYNAMIC ANALYSIS:
According to dynamic analysis by BWOT, A Disturbance is trying to gather convection over south Andaman Sea. Sea Surface Temperature in the suspect region (Andaman Sea) is hovering around 29°C and also over the major parts of Bay of Bengal. That reflects favourable water body.
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Madden Julian Oscillation(RMM) signal is located very weakly over phase 2 with amplitude less than 1. Global model forecast suggests MJO signal is likely to move through phase 2-4(amplitude ≤1) during the whole forecast period. So, it will support the system by enhancing the convective activity over Bay of Bengal. And MJO filtered Velocity Potential Anomaly weakly passing through Africa & Indian Ocean which might become supportive late.
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Also a moderately strong CCKW is likely to pass through Bay of Bengal between 5-8/9th Dec, which will make favourable environment with bringing an additional convective envelope. Also, Rossby induced EWB might boost up the northern periphery of the system to have stronger winds to the north.
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But wind Shear is currently moderate to high & likely to offset by outflow during the intensification period, which will allow some gradual intensification. But shear is likely to increase from 7th December to blow the convection far from the center & cause broad nature.
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Thus, the above mentioned parameters will support the development of a Depression/Deep Depression over South West Bay of Bengal between 6-8th Dec. And a bit intensification up to a Cyclonic Storm is in consideration if shear reduces.
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◾ LANDFALL & MAX INTENSITY:-
Landfall is anticipated between Tamil Nadu to South Andhra Pradesh coast as a Depression/Deep Depression/Minimal CS around 9-10 Dec 2022. The system could peak near 55-85kph(~1min) during the forecast period.
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⚠️EFFECTS:-
Due to the direct influence of the Potential System, “South East coastal India including Andhra Pradesh & Tamil Nadu could have moderate to Very Heavy rain along with Tropical Squalls between 9-11/12 Dec 2022. While Eastern India & Bangladesh could have partly to mostly cloudy skies.
•South & SW Bay of Bengal could have very rough seas between 6-11 Dec 2022. And coastal areas of Tamil Nadu and south Andhra Pradesh could experience 55-75kph winds with gusting up to 75-95kph.
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☔RAINFALL:-
Due to the direct influence of the Potential System, “South East coastal India including Andhra Pradesh & Tamil Nadu could have moderate to Very Heavy rain along with Tropical Squalls between 9-11/12 Dec 2022. While Eastern India & Bangladesh could have partly to mostly cloudy skies.
See the graphic to see the development area & heavy rainfall potential area.
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*NB: This forecast includes Rainfall Activity only by direct influence of the Tropical system which is based on the probable track.
It could be changed if the track changes!
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Resources used in this analysis: Global Models, Himawari 8 Satellite, EWP, ER, CCKW, 200hPa VP, 850hpa Vorticity, 500hPa Vorticity, STR, 200hpa Winds, Sea Surface Temperature, OLR, EWB, ITCZ position, Synoptic Chart, Wind Shear.
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★NOTE:-
These informations are based on Present conditions & it might be changed somewhere during the entire forecast period.
So, keep eye on the latest update for better information.
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Thanks, ©Bangladesh Weather Observation Team (BWOT).