BOB: JAWAD - Post-Tropical

[Hayabusa]

94W INVEST 211126 1200 7.0N 109.7E WPAC 15 0

[Hayabusa]

ABPW10 PGTW 280600
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/SIGNIFICANT TROPICAL WEATHER ADVISORY FOR THE WESTERN AND
/SOUTH PACIFIC OCEANS/280600Z-290600ZNOV2021//
REF/A/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/280552ZNOV2021//
AMPN/REF A IS A TROPICAL CYCLONE FORMATION ALERT.//
RMKS/
1. WESTERN NORTH PACIFIC AREA (180 TO MALAY PENINSULA):
A. TROPICAL CYCLONE SUMMARY: NONE.
B. TROPICAL DISTURBANCE SUMMARY:
(2) AN AREA OF CONVECTION (INVEST 94W) HAS PERSISTED NEAR 6.8N
108.2E, APPROXIMATELY 251 NM SOUTH-SOUTHEAST OF HO CHI MINH,
VIETNAM. ANIMATED MULTISPECTRAL SATELLITE IMAGERY REVEALS A BROAD
AND WEAKLY DEFINED LLCC WITH TURNING IN THE UPPER LEVELS. A 272135Z
SSMIS 91GHZ IMAGE REVEALS BROAD, FRAGMENTED CONVECTIVE BANDING AND
NO DISCRETE LLCC. UPPER-LEVEL ANALYSIS INDICATES THAT THE SYSTEM IS
IN A MARGINALLY FAVORABLE ENVIRONMENT DEFINED BY LOW TO MODERATE
VWS, MODERATE DIVERGENCE ALOFT AND PRONOUNCED POLEWARD OUTFLOW.
ADDITIONALLY WARM (29-30C) SEA SURFACE TEMPERATURES ARE CONDUCIVE
FOR DEVELOPMENT. THE BULK OF THE GLOBAL MODELS ARE IN GENERAL
AGREEMENT REGARDING THE WESTWARD TRACK OF 94W ACROSS THE STRAIT OF
MALACCA INTO THE BAY OF BENGAL WITH SIGNIFICANT DEVELOPMENT IN THE
ANDAMAN SEA. THE ECMWF DETERMINISTIC MODEL, HOWEVER, INDICATES
SLOWER DEVELOPMENT AND A WEAKER SYSTEM. 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.

[wxman57]

Scatterometer data suggests it's already a depression with 30 kt winds.

[ElectricStorm]

If the GFS verifies this could actually become a pretty dangerous system. Areas in the BOB need to watch this one carefully.

[Hayabusa]

WTIO21 PGTW 020230
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT//
REF/A/JOINT TYPHOON WRNCEN PEARL HARBOR HI/020221Z DEC 21//
AMPN/REF IS TROPICAL CYCLONE FORMATION ALERT (WTIO21 PGTW 020230)//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
115 NM EITHER SIDE OF A LINE FROM 9.5N 90.8E TO 13.5N 85.4E
WITHIN THE NEXT 12 TO 24 HOURS. AVAILABLE DATA DOES NOT JUSTIFY
ISSUANCE OF NUMBERED TROPICAL CYCLONE WARNINGS AT THIS TIME.
WINDS IN THE AREA ARE ESTIMATED TO BE 20 TO 25 KNOTS. METSAT
IMAGERY AT 020200Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 9.6N 90.4E. THE SYSTEM IS MOVING WEST-NORTHWESTWARD AT 12
KNOTS.
2. REMARKS:THE AREA OF CONVECTION (INVEST 94W) PREVIOUSLY LOCATED
NEAR 9.2N 91.6E IS NOW LOCATED NEAR 9.6N 90.4E, APPROXIMATELY 629NM
EAST-SOUTHEAST OF CHENNAI, INDIA. A 2230Z SSMIS 91HZ IMAGE DEPICTS
DISORGANIZED CONVECTIVE BANDS ON THE NORTHWESTERN BOUNDARY OF SOME
LOW LEVEL TURNING WHILE MORE RECENT ANIMATED MULTISPECTRAL IMAGERY
REVEALS A MASS OF CONVECTION CONSOLIDATING OVER AN OBSCURED LOW
LEVEL CIRCULATION. 94W IS AT THE LIMINAL POINT OF ITS MATURATION,
CURRENTLY EXISTING IN A BOUNDARY LAYER OF MODERATE (20 KTS) TO LOW
(05-10 KTS) VERTICAL WIND SHEAR (VWS) AND AS IT CONTINUES NORTHWEST
ACROSS THE BAY OF BENGAL 94W WILL ENTER A POCKET OF LOW VWS.
ACCOUNTING FOR THAT, THE EXCELLENT POLEWARD OUTFLOW, AND WARM SEA
SURFACE TEMPERATURES (29-30 C) 94W WILL ENTER AN ENVIRONMENT
FAVORABLE FOR TC DEVELOPMENT. DYNAMIC MODELS SUGGEST 94W WILL REACH
THE 35KT WARNING THRESHOLD, HOWEVER FURTHER DEVELOPMENT IS
LACKADAISICAL AS THE SYSTEM TRACKS WEST-NORTHWEST TOWARD INDIA.
MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 20 TO 25 KNOTS.
MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1004 MB. THE
POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE
WITHIN THE NEXT 24 HOURS IS HIGH.
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED BY
030230Z.
//
NNNN

[aspen]

If the GFS verifies this could actually become a pretty dangerous system. Areas in the BOB need to watch this one carefully.

The GFS has not verified. Add 94W to a long list of overhyped BoB systems. It does pretty badly in this part of the IO.

[Hayabusa]

WDIO31 PGTW 030300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 05B (FIVE) WARNING NR
001//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
INITIAL POSITION: 14.0N 86.1E
INITIAL INTENSITY: 35 KTS
GEOGRAPHIC REFERENCE: 532 NM SOUTH-SOUTHWEST OF KOLKATA, INDIA
MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 14 KTS
SIGNIFICANT WAVE HEIGHT: 12 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A WELL
DEFINED MID-LEVEL ROTATION SIGNATURE, WITH STRONG FLARING
CONVECTION DISPLACED TO THE NORTHWEST OF THE ASSESSED LOW LEVEL
CIRCULATION CENTER. WHILE THE DEEPEST OF THE CONVECTION IS
DISPLACED A BIT TO THE NORTHWEST, THE LOW LEVEL CIRCULATION CENTER
(LLCC) HAS TUCKED UNDER THE SOUTHEASTERN CORNER OF THE CONVECTIVE
ENVELOPE. THE INITIAL POSITION IS PLACED WITH ONLY MEDIUM
CONFIDENCE DUE TO A LACK OF RECENT SCATTEROMETER DATA AND
INCONCLUSIVE MICROWAVE DATA FROM 022116Z. THE INITIAL INTENSITY IS
ASSESSED AT A GENEROUS 35 KNOTS WITH LOW CONFIDENCE BASED ON A PGTW
FIX AT 0000Z OF T2.5 (35 KTS) WITH A .40 WRAP. DEMS IS FIXING AT
T2.0 (30 KTS). THE SYSTEM IS TRACKING QUICKLY NORTHWEST ALONG THE
WESTERN PERIPHERY OF DEEP SUBTROPICAL RIDGE CENTERED OVER NORTHERN
THAILAND. THE ENVIRONMENT IS MARGINALLY FAVORABLE, TRENDING
FAVORABLE, WITH WARM SSTS (28-29C) AND ROBUST POLEWARD OUTFLOW. AT
THE CURRENT TIME, VWS IS MODEST, THE CIMSS ANALYSIS DEPICTING A
SMALL POCKET OF LOW SHEAR IN DIRECT VICINITY OF THE LLCC, COCOONED
WITHIN A LARGER AREA OF MODERATE TO HIGH EASTERLY SHEAR. THE
ENVIRONMENTAL EASTERLY FLOW IS HIGHLY DIVERGENT NEAR THE SYSTEM,
PROVIDING STRONG SUPPORT FOR THE ENHANCED CONVECTION, BUT IS
RESULTING IN A WESTWARD TILT WITH HEIGHT OF THE VORTEX BASED ON GFS
AND HWRF CROSS-SECTIONS.

INITIAL WIND RADII BASIS: OTHER

CURRENT STEERING MECHANISM: SOUTHWESTERN PERIPHERY OF A DEEP-LAYER
STR CENTERED OVER NORTHERN THAILAND.

AGENCY DVORAK AND AUTOMATED FIXES:
PGTW: T2.5 - 35 KTS
DEMS: T2.0 - 30 KTS

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
VWS: 10-15 KTS
SST: 28-29 CELSIUS
OUTFLOW: STRONG POLEWARD
OTHER FACTORS: VORTEX TILT

ANALYSIS CONFIDENCE:
INITIAL POSITION: MEDIUM
INITIAL INTENSITY: LOW
INITIAL WIND RADII: LOW

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THIS INITIAL PROGNOSTIC REASONING
MESSAGE ESTABLISHES THE FORECAST PHILOSOPHY.

FORECAST DISCUSSION: TS 05B HAS SLOWLY BUT STEADILY CONSOLIDATED
OVER THE PREVIOUS TWO DAYS, AND HAS NOW REACHED WARNING CRITERIA.
THE SYSTEM IS CURRENTLY TRACKING QUICKLY TOWARDS THE NORTHWEST
ALONG THE SOUTHWEST SIDE OF A DEEP STR TO THE EAST. OVER THE NEXT
24 HOURS, THE SYSTEM WILL SLOW AS IT REACHES THE RIDGE AXIS, ROUND
THE AXIS NEAR TAU 36, THEN ACCELERATE NORTH THEN NORTHEAST THROUGH
THE REMAINDER OF THE FORECAST. THE FORECAST CALLS FOR THE SYSTEM TO
MAKE LANDFALL NEAR TAU 48, THEN SKIRT THE COASTLINE AND PASSING
NEAR KOLKATA BETWEEN TAUS 72 AND 96 BEFORE MOVING INTO CENTRAL
BANGLADESH BY THE END OF THE FORECAST. DUE TO THE PERSISTENT
EASTERLY UPPER-LEVEL FLOW, THE VORTEX OR CORE OF THE SYSTEM IS
TILTED A BIT TO THE WEST. WHILE UPPER-LEVEL FLOW IS EXPECTED TO
SLACKEN SLIGHTLY OVER THE NEXT 24 HOURS, THE VORTEX TILT IS
FORECAST TO REMAIN IN PLACE, WHICH WILL ACT AS A BRAKING MECHANISM
ON THE RATE OF INTENSIFICATION, EVEN IN LIGHT OF THE ROBUST
POLEWARD OUTFLOW IN THE BASE OF A PASSING MID-LATITUDE TROUGH. THUS
THE SYSTEM IS FORECAST TO INTENSIFY AT A LESS THAN CLIMATOLOGICAL
RATE, PEAKING AT 50 KNOTS BY TAU 36, JUST OFFSHORE OF
VISAKHAPATNAM, INDIA. INCREASING SHEAR, DRY AIR ENTRAINING IN FROM
THE INDIA SUBCONTINENT AND FRICTIONAL EFFECTS OVER LAND WILL
CONSPIRE TO STEADILY WEAKEN AND ULTIMATELY DISSIPATE THE SYSTEM
OVER BANGLADESH BY TAU 96.

MODEL DISCUSSION: TRACK GUIDANCE, WITH THE EXCEPTION OF GFS, IS IN
GOOD AGREEMENT ON THE OVERALL SCENARIO, WITH CROSS-TRACK SPREAD
INCREASING AFTER TAU 24, PLACING THE ECMWF AND ECMWF ENSEMBLE
TRACKERS OVER LAND BY TAU 36. THE REMAINDER OF THE TRACKERS KEEP
THE CENTER OFFSHORE UNTIL TAU 48. THE GFS TURNS THE SYSTEM SHARPLY
EASTWARD AFTER TAU 12, WITH A LANDFALL NEAR CHITTAGONG, BUT THIS
SCENARIO IS UNREALISTIC AS THE SYSTEM IS UNLIKELY TO TRACK DIRECTLY
INTO THE STRONG RIDGE. THE JTWC FORECAST LIES JUST INSIDE AND
SLIGHTLY FASTER THAN THE CONSENSUS MEAN WITH MEDIUM CONFIDENCE.
INTENSITY GUIDANCE IS MIXED, WITH THE SHIPS GUIDANCE INDICATING A
PEAK INTENSITY NEAR 65 KNOTS, WHILE THE COAMPS-TC SUGGESTS A PEAK
CLOSER TO 45 KNOTS. THE JTWC FORECAST CLOSELY TRACKS THE HWRF
SOLUTION, JUST SLIGHTLY LOWER THAN CONSENSUS THROUGH TAU 36, THEN
SLIGHTLY ABOVE IT THEREAFTER. OVERALL CONFIDENCE IS LOW DUE TO
UNCERTAINTIES WITH THE AMOUNT OF LAND INTERACTION, WHICH IS
DEPENDENT UPON THE EXACT TRACK.

FORECAST CONFIDENCE:
TRACK 0 - 72 HR: MEDIUM
TRACK 72-120 HR: LOW
INTENSITY 0 - 72 HR: LOW
INTENSITY 72-120 HR: LOW//
NNNN

[Sciencerocks]

[Subtrop]

DEEP DEPRESSION intensified into CYCLONIC STORM 'JAWAD' AT 1130HRS IST. To move northwestwards and reach north Andhra Pradesh – south Odisha coasts by 4th December morning. Thereafter, to recurve north-northeastwards and move along Odisha coast reaching near Puri around 5th December noon.