TC 24S(IRONDRO) intensifying ,TC 25P(HAROLD): potential direct threat to Vanuatu



TC 24S(IRONDRO) ON THE LEFT AND TC 25P(HAROLD) ON THE RIGHT: INTENSIFYING. CLICK ON THE IMAGE TO ANIMATE IF NECESSARY.

CIRA
CIRA
TC 24S(IRONDRO) SOUTH INDIAN
As of 06:00 UTC Apr 03, 2020:
Location: 17.5°S 73.3°E
Maximum Winds: 55 kt ( 100km/h)
Gusts: 70 kt ( 130km/h)
Minimum Central Pressure: 987 mb

REMARKS:
030900Z POSITION NEAR 18.0S 73.8E.
03APR20. TROPICAL CYCLONE (TC) 24S (IRONDRO), LOCATED APPROXIMATELY
626 NM SOUTH OF DIEGO GARCIA, HAS TRACKED SOUTH-SOUTHEASTWARD AT
16 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED
SATELLITE IMAGERY AND A 030447Z MHS 89GHZ MICROWAVE IMAGE INDICATE
TIGHTLY-CURVED BANDING WRAPPING INTO A DEFINED LOW-LEVEL CIRCULATION
CENTER. A 030448Z METOP-B ASCAT BULLSEYE IMAGE REVEALS A WELL-
DEFINED CENTER, WHICH SUPPORTS THE INITIAL POSITION AND INITIAL 34-
AND 50-KNOT WIND RADII ASSESSMENTS. THE INITIAL INTENSITY IS BASED
ON DVORAK INTENSITY ESTIMATES OF T3.5 (55 KNOTS) FROM KNES AND PGTW,
WHICH IS SLIGHTLY HIGHER THAN THE MAXIMUM WINDS (45-50 KNOTS)
OBSERVED IN THE ASCAT IMAGERY. TC 24S WILL TRACK SOUTHEASTWARD ALONG
THE SOUTHWEST FLANK OF A SUBTROPICAL RIDGE POSITIONED TO THE EAST
THROUGH TAU 48. AFTER TAU 48, THE SYSTEM WILL TURN EAST-
SOUTHEASTWARD AS IT TRACKS WITHIN THE MIDLATITUDE WESTERLIES.
WITH THE SOLE EXCEPTION OF NAVGEM, WHICH INDICATES AN ERRONEOUS
EQUATORWARD LOOPING TRACK, NUMERICAL MODEL GUIDANCE IS IN GOOD
AGREEMENT LENDING HIGH CONFIDENCE TO THE JTWC FORECAST TRACK. TC 24S
SHOULD CONTINUE TO INTENSIFY AT A CLIMATOLOGICAL RATE THROUGH TAU 24
DUE TO ROBUST POLEWARD OUTFLOW, ASSOCIATED WITH STRONG WESTERLY FLOW
TO THE SOUTH, LOW VERTICAL WIND SHEAR (VWS) AND WARM SST VALUES (29-
30C). THE SYSTEM IS EXPECTED TO PEAK AT 75 KNOTS AT TAU 24. AFTER
TAU 36, TC 24S WILL BEGIN TO INTERACT WITH THE MIDLATITUDE
WESTERLIES WITH A SHARP INCREASE IN VWS (30+ KNOTS), WHICH WILL LEAD
TO A STEADY WEAKENING TREND. THE SYSTEM SHOULD COMMENCE EXTRA-
TROPICAL TRANSITION (ETT) NEAR TAU 48. BY TAU 72, TC 24S WILL BECOME
EMBEDDED WITHIN THE STRONG WESTERLY FLOW, NEAR THE JET, WITH VWS
INCREASING TO 45-55 KNOTS AND SST VALUES COOLING TO LESS THAN 25C.
TC 24S WILL COMPLETE ETT BY TAU 72 AS IT GAINS FRONTAL
CHARACTERISTICS. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 030600Z IS 22
FEET.

TC 25P(HAROLD) SOUTH PACIFIC
As of 06:00 UTC Apr 03, 2020:
Location: 11.4°S 162.6°E
Maximum Winds: 40 kt ( 75km/h)
Gusts: 50 kt ( 95km/h)

Minimum Central Pressure: 999 mb
REMARKS:
030900Z POSITION NEAR 11.8S 163.0E.
03APR20. TROPICAL CYCLONE (TC) 25P (HAROLD), LOCATED APPROXIMATELY
502 NM NORTHWEST OF PORT VILA, VANUATU, HAS TRACKED EAST-
SOUTHEASTWARD AT 15 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED
INFRARED SATELLITE IMAGERY INDICATES THAT TC 25P IS BEGINNING TO
CONSOLIDATE AS IT TRACKS AWAY FROM THE SOLOMON ISLANDS. A 030801Z
SSMIS 91GHZ IMAGE DEPICTS TIGHTLY-CURVED BANDING WRAPPING INTO A
DEFINED LOW-LEVEL CIRCULATION CENTER. UPPER-LEVEL ANALYSIS REVEALS A
VERY FAVORABLE ENVIRONMENT WITH ROBUST POLEWARD OUTFLOW, LOW
VERTICAL WIND SHEAR AND WARM SST VALUES (30C). THE INITIAL INTENSITY
REMAINS ASSESSED AT 40 KNOTS BASED ON AN AVERAGE OF DVORAK INTENSITY
ESTIMATES RANGING FROM T2.5 TO T3.0 (35 TO 45 KNOTS). HOWEVER, THE
SYSTEM IS EXPECTED TO INTENSIFY AT A HIGHER-THAN-CLIMATOLOGICAL RATE
THROUGH TAU 48 UNDER PERSISTENT VERY FAVORABLE ENVIRONMENTAL
CONDITIONS WITH SOME POTENTIAL FOR RAPID INTENSIFICATION. THE SYSTEM
IS EXPECTED TO PEAK AT 80 KNOTS BY TAU 48 AS IT TRACKS GENERALLY
SOUTHEASTWARD ALONG THE WESTERN PERIPHERY OF A SUBTROPICAL RIDGE
(STR) POSITIONED TO THE EAST. BY TAU 48, THE STEERING ENVIRONMENT IS
EXPECTED TO WEAKEN AS A DEEP MIDLATITUDE SHORTWAVE TROUGH APPROACHES
FROM THE SOUTHWEST AND THE STR TEMPORARILY BUILDS TO THE SOUTH. THIS
WILL LEAD TO A SHORT PERIOD OF SLOW, POSSIBLY QUASI-STATIONARY TRACK
MOTION THROUGH TAU 72. NUMERICAL MODEL GUIDANCE DIVERGES DURING THIS
PERIOD WITH INCREASING UNCERTAINTY IN THE FORECAST TRACK. AFTER TAU
72, UPPER-LEVEL SUBTROPICAL WESTERLIES ASSOCIATED WITH THE BROAD
TROUGH ARE EXPECTED TO STRENGTHEN OVER TC 25P, WHICH WILL SERVE TO
ACCELERATE THE SYSTEM EAST-SOUTHEASTWARD WITH STEADY WEAKENING DUE
TO CONVERGENCE ALOFT AND MODERATE BAROCLINICITY AS INDICATED IN THE
850MB TEMPERATURE FIELDS. OVERALL, THERE IS LOW CONFIDENCE IN THE
JTWC FORECAST TRACK DUE TO THE COMPLEX, EVOLVING STEERING PATTERN.
MAXIMUM SIGNIFICANT WAVE HEIGHT AT 030600Z IS 14 FEET.

TC 24S: WARNING 3: PEAK INTENSITY ( 75KTS/CAT1) FORECAST IN 24H.

CIMSS/JTWC
CIMSS/JTWC

 

TC 25P: WARNING 3: PEAK INTENSITY (80KTS/CAT1) FORECAST IN 48H BUT WITH SOME POTENTIAL FOR RAPID INTENSIFICATION.


TC 24S: ASCAT AT 03/0448UTC

FNMOC
FNMOC

TC 24S: TRACK AND INTENSITY GUIDANCE


TC 25P: TRACK AND INTENSITY GUIDANCE


03/0530UTC

JTWC
JTWC


03/00UTC

FNMOC
FNMOC
Rédigé par PATRICK HOAREAU le Vendredi 3 Avril 2020 à 13:36