ARB: GATI - Ex-Very Severe Cyclonic Storm

[Nancy Smar]

95A.INVEST.20kts.1007mb.11.3N.63.5E

[doomhaMwx]

95A INVEST 201120 0600 11.3N 63.5E IO 20 1007
95A INVEST 201120 0000 11.0N 65.0E IO 15 1010
95A INVEST 201119 1800 10.9N 66.5E IO 15 1010
95A INVEST 201119 1200 10.9N 67.5E IO 15 1010
95A INVEST 201119 0600 10.9N 68.5E IO 15 1010

This is near 94A which was designated a few days ago.

[doomhaMwx]

ABIO10 PGTW 201800

AN AREA OF CONVECTION (INVEST 95A) HAS PERSISTED NEAR 11.2N 62.7E, APPROXIMATELY 518 NM EAST OF SOCOTRA. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY AND A 201202Z SSMIS F-16 91H IMAGE DEPICT FLARING DEEP CONVECTION BEGINNING TO WRAP INTO A LOW LEVEL CIRCULATION CENTER. 95A HAS BECOME THE DOMINANT CIRCULATION OVER 94A WHICH HAS NOW BEEN DOWNGRADED TO AN INVEST ONLY INVEST 95A IS CURRENTLY IN A FAVORABLE ENVIRONMENT FOR DEVELOPMENT WITH LOW (5-10 KTS) VERTICAL WIND SHEAR, WARM (28-29 CELSIUS) SEA SURFACE TEMPERATURES AND GOOD WESTWARD OUTFLOW ALOFT. GLOBAL MODELS ARE IN GOOD AGREEMENT THAT INVEST 95A WILL CONTINUE A GENERALLY WESTWARD TRACK WITH STEADY INTENSIFICATION OVER THE NEXT 24 HOURS. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 15 TO 20 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1005 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS IS LOW.

[doomhaMwx]

ABIO10 PGTW 210200

THE AREA OF CONVECTION (INVEST 95A) PREVIOUSLY LOCATED
NEAR 8.0N 56.2E IS NOW LOCATED NEAR 10.9N 60.5E, APPROXIMATELY 340
NM EAST OF SOCOTRA. ANIMATED ENHANCED INFRARED IMAGERY AND A 202350Z
SSMI F-15 85HZ PASS DEPICTS IMPROVING CONVECTIVE ORGANIZATION
ASSOCIATED WITH A DEVELOPING LOW LEVEL CIRCULATION CENTER (LLCC).
INVEST 95A IS EMBEDDED WITHIN IN A LARGE AREA OF MONSOON TROUGHING,
WITH TWO ADDITIONAL CIRCULATIONS (INVESTS 94A AND 96A). INVEST 95A
APPEARS TO HAVE THE MOST FAVORABLE CONDITIONS, AND IS BECOMING THE
DOMINANT CIRCULATION. THERE IS CURRENTLY STRONG DIVERGENCE ALOFT
PROVIDING GOOD OUTFLOW. LOW (5-10 KNOTS) VERTICAL WIND SHEAR AND 27
DEGREE CELSIUS SEA SURFACE TEMPERATURES PROVIDE A FAVORABLE
ENVIRONMENT FOR FURTHER DEVELOPMENT. GLOBAL MODELS ARE IN GOOD
AGREEMENT THAT INVEST 95A WILL CONTINUE A GENERALLY WESTWARD TRACK
WITH STEADY INTENSIFICATION OVER THE NEXT 24 HOURS. MAXIMUM
SUSTAINED SURFACE WINDS ARE ESTIMATED AT 25 TO 30 KNOTS. MINIMUM SEA
LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1003 MB. THE POTENTIAL FOR
THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24
HOURS IS UPGRADED TO MEDIUM.

DEMS-RSMC TROPICAL CYCLONES NEW DELHI DATED 21.11.2020

YESTERDAY’S LOW PRESSURE AREA OVER CENTRAL PARTS OF SOUTH ARABIAN
SEA LAY AS A WELL MARKED LOW PRESSURE AREA OVER SOUTHWEST ARABIAN
SEA (AS) AND NEIGHBOURHOOD IN THE EARLY MORNING (0000 UTC) AND
PERSISTED OVER THE SAME REGION AT 0300 UTC OF TODAY, THE 21ST
NOVEMBER, 2020. IT IS LIKELY TO MOVE WEST-NORTHWESTWARDS AND
CONCENTRATE INTO A DEPRESSION DURING NEXT 24 HOURS.

[doomhaMwx]

 https://twitter.com/doomhaMwx/status/1330086670302121984

WTIO21 PGTW 210800

REMARKS: THE AREA OF CONVECTION (INVEST 95A) PREVIOUSLY LOCATED
NEAR 10.9N 60.5E IS NOW LOCATED NEAR 11.0N 59.3E, APPROXIMATELY 323
NM EAST-SOUTHEAST OF SOCOTRA. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY INDICATES LOW LEVEL CLOUD LINES WRAPPING INTO A PARTIALLY
EXPOSED LOW LEVEL CIRCULATION CENTER. A 210621Z METOP-B 89GHZ
SATELLITE IMAGE REVEALS DEEP CONVECTIVE BANDING WRAPPING INTO THE
NORTHWESTERN QUADRANT. A 210504Z ASCAT-A PASS REVEALS 30-35KT WINDS
IN THE NORTHERN SEMICIRCLE WITH 15-20KT WINDS IN THE SOUTHERN
SEMICIRCLE. INVEST 95A IS IN A FAVORABLE ENVIRONMENT FOR DEVELOPMENT
WITH LOW (<15KTS) VERTICAL WIND SHEAR, GOOD OUTFLOW ALOFT, AND WARM
(27-28C) SEA SURFACE TEMPERATURES. GLOBAL MODELS INDICATE INVEST 95A
WILL CONTINUE TO TRACK GENERALLY WESTWARD WITH SOME INTENSIFICATION
OVER THE NEXT 24 HOURS. MAXIMUM SUSTAINED SURFACE WINDS ARE
ESTIMATED AT 25 TO 30 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED
TO BE NEAR 1003 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A
SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS IS HIGH.

[wxman57]

ASCAT indicates it's a 35-40 kt TS.

[aspen]

ASCAT indicates it's a 35-40 kt TS.

Odds are it never gets upgraded to a TS. Something similar happened to a TC last year that should’ve been named Amphan.

[Vince_and_Grace_fan]

According to the ASCAT-B pass at 06:21 UTC the southern cyclone (96A) also developed into a 35-kt TS for a short time, but it became absorbed by this (03A) cyclone.
Here is a great satellite picture from Metop-C:



And the absorbation:

[doomhaMwx]

REMARKS:
212100Z POSITION NEAR 10.8N 55.0E.
21NOV20. TROPICAL CYCLONE 03A (THREE), LOCATED APPROXIMATELY 634
NM EAST OF ADEN, YEMEN, HAS TRACKED WESTWARD AT 15 KNOTS OVER THE
PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY
REVEALS SYMMETRICAL, FLARING DEEP CONVECTION OVER TOP OF THE
OBSCURED LOW LEVEL CIRCULATION CENTER (LLCC). THE INITIAL POSITION
IS PLACED WITH HIGH CONFIDENCE BASED ON TWO ASCAT BULLSEYE PASSES,
AT 211612Z AND 211727Z AND A WELL-DEFINED LOW EMISSIVITY REGION
EVIDENT IN TH 211725 AMSU-B 89GHZ MICROWAVE IMAGE. THE 211612Z ASCAT-
A BULLSEYE SCATTEROMETER PASS INDICATES A SWATH OF 35-40 KNOT WINDS
ARRAYED ON THE WESTERN SIDE OF THE CIRCULATION, WITH 30-35 KNOTS
ELSEWHERE IN THE SOUTHWESTERN AND NORTHEASTERN QUADRANTS. THE MOST
RECENT PGTW DVORAK CURRENT INTENSITY ESTIMATE OF T2.5 (35 KNOTS)
LENDS ADDITIONAL SUPPORT TO THE INITIAL INTENSITY. WITH LOW (5-10
KNOTS) VWS, LUKEWARM (27-28 DEG C) AND MODERATE WESTWARD AND
EQUATORWARD OUTFLOW, THE ENVIRONMENT SUPPORTS SOME MINIMAL NEAR-TERM
INTENSIFICATION. TC 03A IS TRACKING JUST SOUTH OF DUE WEST ALONG THE
SOUTHERN PERIPHERY OF A DEEP-LAYER STR OVER THE SOUTHERN ARABIAN
PENINSULA. TC 03A IS FORECAST TO CONTINUE TRACKING WEST-
SOUTHWESTWARD THROUGH TAU 24, BEFORE MAKING LANDFALL ALONG THE
NORTHEAST SOMALI COAST NEAR RAS HAFUN, BEFORE SHIFTING TO A WEST-
NORTHWEST TRACK AFTER LANDFALL. THE SYSTEM IS FORECAST TO INTENSITY
SLIGHTLY OVER THE NEXT 12 HOURS TO A PEAK OF 40 KNOTS, BEFORE
WEAKENING SLIGHTLY BEFORE LANDFALL DUE TO INCREASED VWS AND COOLER
WATERS. AFTER LANDFALL, THE SYSTEM IS FORECAST TO RAPIDLY WEAKEN
OVER THE RUGGED TERRAIN OF THE NORTHEAST SOMALIA, DISSIPATING AS A
TROPICAL CYCLONE BY TAU 48. DYNAMIC MODEL GUIDANCE IS IN POOR
AGREEMENT WITH THE EGRR AND ECMWF DEPICTING A TRACK ACROSS THE
NORTHERN COAST OF SOMALIA WHILE THE NAVGEM AND GFS SOLUTIONS MOVE
THE VORTEX SOUTHWARD, PARALLEL TO THE EAST COAST OF SOMALIA AND LOSE
THE VORTEX ALTOGETHER BY TAU 48. THE JTWC FORECAST TRACK LIES CLOSE
TO THE ECMWF SOLUTION WITH LOW CONFIDENCE. MAXIMUM SIGNIFICANT WAVE
HEIGHT AT 211800Z IS 14 FEET. NEXT WARNINGS AT 220300Z, 220900Z,
221500Z AND 222100Z.

[doomhaMwx]

Heh no surprise here. IMD lags behind these Arabian Sea systems, especially this far west.

BULLETIN NO. : 01(ARB/04/2020)

Latest satellite and Ship observations indicate that the well marked low pressure area over
southwest Arabian Sea has concentrated into a Depression and lay centred at 2330 hrs IST of
21st November 2020 over southwest Arabian Sea near Lat. 11.2° N and Long.57.4°E, about 410
km east-southeast of Socotra (Yemen) and 730 km east of Alula (Somalia). It is very likely to
move nearly west-northwestwards and intensify into a deep depression during next 24 hours.

[wxman57]

This is not a 25kt TD as per IMD. Not sure what they were looking at. Their outlook didn't have it at a "high" chance of development this morning until after models had it well inland and dissipating over Somalia. Satellite appearance is of a 40-50 kt TS.

[doomhaMwx]

03A THREE 201122 0000 10.6N 54.2E IO 40 1002

REMARKS:
220300Z POSITION NEAR 10.6N 53.6E.
22NOV20. TROPICAL CYCLONE 03A (THREE), LOCATED APPROXIMATELY 556
NM EAST-SOUTHEAST OF ADEN, YEMEN, HAS TRACKED WESTWARD AT 14
KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR)
SATELLITE IMAGERY SHOWS A VERY COMPACT, WELL-ORGANIZED SYSTEM WITH
FLARING DEEP CONVECTION WRAPPING AROUND THE ASSESSED LOW-LEVEL
CIRCULATION CENTER (LLCC). THE SYSTEM APPEARS TO HAVE QUICKLY
CONSOLIDATED AFTER ABSORBING MOST OF THE VORTICITY THAT WAS
ASSOCIATED WITH INVEST AREA 96A. THE INITIAL POSITION IS PLACED WITH
LOW CONFIDENCE DUE TO A DEARTH OF MICROWAVE OR SCATTEROMETER DATA,
WITH POSITIONING BEING LIMITED TO ANALYSIS OF THE WRAP IN THE
CONVECTIVE BANDS AND THE PGTW FIX POSITION. THE INITIAL INTENSITY IS
SET AT 40 KNOTS WITH MODERATE CONFIDENCE, SLIGHTLY HIGHER THAN THE
PGTW DVORAK CURRENT INTENSITY ESTIMATE OF T2.5 (35 KNOTS) BASED ON
AN ADVANCED DVORAK TECHNIQUE (ADT) ESTIMATE OF T2.7 (39 KNOTS), AND
A SATELLITE CONSENSUS ESTIMATE OF 43 KNOTS. TC 03A IS CURRENTLY IN A
FAVORABLE ENVIRONMENT WITH LOW (5-10 KNOTS) VWS, WARM (27-28 DEG C)
SSTS AND MODERATE EQUATORWARD AND WESTWARD OUTFLOW CHANNELS. THE
SYSTEM IS TRACKING WESTWARD ALONG THE SOUTHERN PERIPHERY OF A DEEP-
LAYER STR OVER THE SOUTHEASTERN SAUDI ARABIAN PENINSULA. TC 03A IS
FORECAST TO CONTINUE ITS CURRENT WEST-SOUTHWEST TO WESTWARD MOVEMENT
THOUGH THE FORECAST PERIOD, ALONG THE SOUTHERN EDGE OF THE
PREVIOUSLY DISCUSSED STR OVER THE SAUDI PENINSULA. AS THE SYSTEM
WEAKENS AFTER MAKING LANDFALL NEAR RAS HAFUN AROUND TAU 18, THE LOW
LEVEL CIRCULATION WILL MEANDER SOMEWHAT, CLOSELY TRACKING THE
TERRAIN FEATURES AND THE LOW-LEVEL EAST-NORTHEAST FLOW. IN THE NEAR-
TERM, TC 03A IS FORECAST TO TAKE ADVANTAGE OF THE FAVORABLE
ENVIRONMENT AND CONTINUE TO SLOWLY INTENSITY TO A PEAK OF 45 KNOTS
BY TAU 12. AFTER LANDFALL NEAR TAU 18, THE SYSTEM WILL BEGIN TO
RAPIDLY WEAKEN OVER THE RUGGED TERRAIN OF NORTHEAST SOMALIA. WHILE
REMNANTS OF THE CIRCULATION MAY TRACK INTO THE GULF OF ADEN, TC 03A
IS EXPECTED TO DISSIPATE AS A TROPICAL CYCLONE OVER LAND AT OR
BEFORE TAU 48. DYNAMIC MODEL GUIDANCE IS A POOR AGREEMENT, WITH THE
GFS AND THE GFS ENSEMBLE DEPICTING A SHARP TURN SOUTHWARD AND
DISSIPATION OVER WATER BY TAU 48, WHILE THE NAVGEM SOLUTION TRACKS
THE SYSTEM SHARPLY NORTHWEST INTO THE GULF OF ADEN BY TAU 24. THE
REMAINDER OF THE MODEL TRACKERS AND THE JTWC OFFICIAL FORECAST
REMAIN CONSISTENT WITH THE PREVIOUS FORECAST, SLIGHTLY NORTH OF THE
MULTI-MODEL CONSENSUS WITH LOW CONFIDENCE BEYOND TAU 24 DUE TO THE
VERY SHARP DISAGREEMENT IN MODEL SOLUTIONS AFTER THIS POINT.
MAXIMUM SIGNIFICANT WAVE HEIGHT AT 220000Z IS 16 FEET. NEXT
WARNINGS AT 220900Z, 221500Z, 222100Z AND 230300Z.//
NNNN

[TorSkk]

 https://twitter.com/webberweather/status/1330333711875911682



 https://twitter.com/webberweather/status/1330342029277138951

[supercane4867]

IMD is trash.

 https://twitter.com/derekortt/status/1330341840474824704

[doomhaMwx]

Oh wow that's mean, the latest microwave pass is unexpected. SATCON a few hrs ago (@ ~22Z) already support 55kts, and likely to go up once new MW data is incorporated.

CURRENT ESTIMATE
Date (mmddhhmm): 11212205
SATCON: MSLP = 994 hPa MSW = 54 knots
SATCON Member Consensus: 47.0 knots
Pressure -> Wind Using SATCON MSLP: 76 knots
Distance to Outer Closed Isobar Used is 95 nm
Eye Size Correction Used is 4.1 knots Source: MW

Member Estimates

ADT: 1006 hPa 39 knots Scene: CDO Date: NOV220015
CIMSS AMSU: 998 hPa 54 knots Bias Corr: 0 (MW) Date: 11211723
ATMS: 990.0 hPa 55.0 knots Date: 11212205
SSMIS: 990.0 hPa 55.0 knots Date: 11212205
CIRA ATMS: hPa knots Date:

[Ed_2001]

FYI as far as the records go (which, granted, isn't very far in this part of the world) there have never been a hurricane-strengthed cyclone landfall in Somalia. Another thing to add to the 2020 bucket list it looks like. Fortunately, the region its impacting seem to be fairly sparsely populated but people in the region are going to get an rude awakening if they don't get adequately warned.

[wxman57]

It's unfathomable that a tropical cyclone specialist could look at this and identify it as a "deep depression" with 30 kt winds. I'm deeply-depressed...

[Cunxi Huang]

 https://twitter.com/CharlieFurWx/status/1330361794431512578

[MarioProtVI]

Baffled how poorly they are handling this. In fact 06z just came out early from JTWC and they somehow went with only 55 kt despite a legit eye popping out on satellite. Wtf.

[doomhaMwx]

JTWC revised their 00Z estimate to 50kts by the way. Interestingly, they have an 06Z data ready.

03A THREE 201122 0600 10.4N 52.6E IO 55 982
03A THREE 201122 0000 10.5N 53.8E IO 50 998
03A THREE 201121 1800 10.8N 55.6E IO 35 1005
03A THREE 201121 1200 11.0N 57.1E IO 30 1003
03A THREE 201121 0600 11.2N 58.9E IO 30 1003
03A THREE 201121 0000 11.0N 60.5E IO 30 1003
03A THREE 201120 1800 11.0N 61.7E IO 25 1006
03A THREE 201120 1200 11.2N 62.7E IO 20 1005
03A THREE 201120 0600 11.2N 63.7E IO 20 1007
03A THREE 201120 0000 11.0N 65.0E IO 15 1010
03A THREE 201119 1800 10.9N 66.5E IO 15 1010
03A THREE 201119 1200 10.9N 67.5E IO 15 1010
03A THREE 201119 0600 10.9N 68.5E IO 15 1010