03UTC: TC WALLACE(23S) poorly organized still forecast to intensify slowly next 36/48 hours


Warning 9/JTWC


WARNING 9/JTWC
WARNING 9/JTWC
https://www.facebook.com/groups/1817419381676514/
TC WALLACE(23S)
As of 00:00 UTC Apr 07, 2019:

Location: 12.8°S 120.6°E
Maximum Winds: 45 kt ( 85km/h)
Gusts: 55 kt ( 100km/h)

Minimum Central Pressure:  mb
REMARKS:
070300Z POSITION NEAR 12.9S 120.1E.
TROPICAL CYCLONE 23S (WALLACE), LOCATED APPROXIMATELY 680 NM
NORTHEAST OF LEARMONTH, AUSTRALIA, HAS TRACKED WESTWARD AT 16
KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY (MSI) DEPICTS DIMINISHED DEEP CONVECTION BEING SHEARED TO
THE WEST OF A PARTIALLY EXPOSED LOW LEVEL CIRCULATION CENTER (LLCC)
DUE TO MODERATE TO STRONG (20 TO 25 KNOTS) EASTERLY VERTICAL WIND
SHEAR (VWS). THE INITIAL POSITION IS BASED WITH FAIR CONFIDENCE ON
THE PARTIALLY EXPOSED LLCC IN THE MSI LOOP, AND ON A 052232Z SSMIS
37GHZ IMAGE SHOWING A CONVECTIVE BAND WRAPPING AROUND THE WEST SIDE
OF A LOW REFLECTIVITY FEATURE. THE INITIAL INTENSITY REMAINS
ASSESSED AT 45 KNOTS BASED ON DVORAK ESTIMATES OF T3.0 (45 KNOTS)
FROM PGTW AND KNES, THOUGH THE APRF ESTIMATE INCREASED TO T3.5 (55
KTS) AND A 052233Z SATCON ESTIMATE IS 50 KTS. TC 23S IS FORECAST TO
TRACK SOUTHWESTWARD ALONG THE NORTHERN PERIPHERY OF A DEEP-LAYERED
SUBTROPICAL RIDGE (STR) CENTERED OVER WESTERN AUSTRALIA THROUGH TAU
36. NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT THROUGH THIS PHASE
OF THE FORECAST WITH A 100NM SPREAD IN SOLUTIONS AT TAU 36. TC 23S
SHOULD SLOWLY INTENSIFY TO A PEAK OF 60 KNOTS BY TAU 36 AS VWS
GRADUALLY DECREASES, SUPPORTED BY ROBUST POLEWARD OUTFLOW AND WARM
SEA SURFACE TEMPERATURES (29-30 DEGREES CELSIUS). THE LATE-TERM
STEERING ENVIRONMENT IS COMPLEX, WITH AN APPROACHING UPPER-LEVEL
MIDLATITUDE TROUGH ERODING THE WESTERN EDGE OF THE STR TO THE EAST
AND BRINGING UPPER-LEVEL WESTERLIES OVER THE SYSTEM, WHILE ANOTHER
STR BUILDS IN FROM THE WEST; HOWEVER, AT THIS POINT THE SYSTEM WILL
HAVE WEAKENED, AND MAY BE SUBJECT TO SOUTHEASTERLY LOWER-LEVEL
STEERING FLOW FROM A SURFACE HIGH PRESSURE CENTER TO THE SOUTHEAST,
AND LATER, RIDGING THAT BUILDS IN FROM THE SOUTHWEST. THE UPPER
LEVEL WESTERLIES WILL BRING INCREASED VWS AND CONVERGENCE ALOFT,
LEADING TO DISSIPATION BY TAU 120. NUMERICAL MODEL GUIDANCE DIVERGES
SIGNIFICANTLY AFTER TAU 48 WITH A LARGE SPREAD IN SOLUTIONS, ABOUT
310 NM AT TAU 120 EXCLUDING NAVGEM, WHICH ERRONEOUSLY RECURVES THE
SYSTEM INTO THE STR. GALWEM, THE UKMET MODEL, AND THE GFS ENSEMBLE
TURN THE SYSTEM SOUTHWARD TO SOUTHWESTWARD TOWARDS THE BREAK BETWEEN
THE STRS WHILE ECMWF, THE ECMWF ENSEMBLE, AND GFS INDICATE A STEADY
WESTWARD TRACK, AND THE GFS ENSEMBLE MEAN HAS TRENDED NORTH TOWARDS
A WEST-SOUTHWESTWARD TRACK. ALL MODELS FORECAST THE BREAK IN THE
STRS TO DEVELOP BY TAU 72 EXCEPT FOR ECMWF, WHICH DOES NOT PREDICT
THE BREAK UNTIL AFTER TAU 96. THE GFS SOLUTION, HOWEVER, DOES NOT
TURN THE SYSTEM SOUTHWARD IN RESPONSE TO THE BREAK, FAVORING THE
SOUTHEASTERLY LOW-LEVEL FLOW OR SOUTHERLY DEEP-LAYER FLOW FROM THE
STR TO THE WEST AS DOMINANT STEERING INFLUENCES INSTEAD.
ADDITIONALLY, THE GFS AND ECMWF TRACKS STAY NORTH OF THE MIDLATITUDE
WESTERLIES AND MAINTAIN A FASTER TRACK SPEED. THE JTWC TRACK
FORECAST CONTINUES WEST-SOUTHWESTWARD THROUGH THE END OF THE
FORECAST PERIOD, POSITIONED BETWEEN THE TWO SCENARIOS, AND SLOWS AT
LATER TAUS IN RESPONSE TO THE UPPER-LEVEL WESTERLIES MOVING
OVERHEAD. IT IS HEDGED SLIGHTLY NORTH OF THE MULTI-MODEL CONSENSUS,
WHICH IS BEING DRAGGED SOUTHWARD BY THE OUTLIER NAVGEM. MAXIMUM
SIGNIFICANT WAVE HEIGHT AT 070000Z IS 18 FEET. NEXT WARNINGS AT
070900Z, 071500Z, 072100Z AND 080300Z.//
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WARNING 9/JTWC
WARNING 9/JTWC

 

0247UTC
0247UTC

 

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0247UTC


2233UTC
2233UTC



Rédigé par PATRICK HOAREAU le Dimanche 7 Avril 2019 à 08:15