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03UTC: TC HALEH(17S) category2 US is weakening but has still a good microwave signature


Warning 16/JTWC


Microwave at 0042UTC
Microwave at 0042UTC
TC HALEH 17S
https://www.facebook.com/groups/1817419381676514/
As of 00:00 UTC Mar 06, 2019:
Location: 22.3°S 71.0°E
Maximum Winds: 85 kt (160km/h)
Gusts: 105 kt (195km/h)
Minimum Central Pressure: 959 mb
REMARKS:
060300Z POSITION NEAR 22.6S 70.7E.
TROPICAL CYCLONE 17S (HALEH), LOCATED APPROXIMATELY 777 NM EAST-
SOUTHEAST OF PORT LOUIS, MAURITIUS, HAS TRACKED SOUTH-SOUTHWESTWARD
AT 07 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED
SATELLITE IMAGERY DEPICTS A COMPACT ASYMMETRIC SYSTEM WITH AN
INTERMITTENT EYE FEATURE AND OCCASIONAL WELL-DEFINED CONVECTIVE
BANDS. A 060041Z SSMIS 91GHZ MICROWAVE IMAGE SHOWS LIMITED
CONVECTIVE BANDING WITH A WEAKENING EYEWALL SURROUNDING A MICROWAVE
EYE FEATURE AND THE BULK OF THE DEEP CONVECTION SOUTH OF THE CENTER,
GIVING GOOD CONFIDENCE IN THE INITIAL POSITION. THE INITIAL
INTENSITY IS ASSESSED AT 85 KNOTS BASED ON DVORAK CURRENT INTENSITY
ESTIMATES RANGING FROM T4.5 TO 5.0 (77 TO 92 KNOTS) AS WELL AS AN
ADT ESTIMATE OF 80 KTS AT 052345Z. UPPER-LEVEL ANALYSIS REVEALS A
FAVORABLE ENVIRONMENT WITH LOW (10-15 KNOTS) VERTICAL WIND SHEAR
(VWS), WARM (28-29 DEGREES CELSIUS) SEA SURFACE TEMPERATURES (SST)
AND GOOD POLEWARD OUTFLOW. HOWEVER, CONVERGENT FLOW ASSOCIATED WITH
UPPER-LEVEL TROUGHING OVER THE NORTHERN PERIPHERY AND WESTERN
PERIPHERY IS HINDERING EQUATORWARD OUTFLOW. TC 17S IS TRACKING
SOUTHWESTWARD ALONG THE WESTERN PERIPHERY OF A NORTH-SOUTH ORIENTED
SUBTROPICAL RIDGE (STR). TC 17S WILL THEN SHIFT TO A SOUTH-
SOUTHWESTWARD TRACK AS ANOTHER STR POSITIONED TO THE SOUTH WEAKENS
AND MOVES EASTWARD BECOMING THE PRIMARY STEERING INFLUENCE. AFTER
TAU 48, TC 17S WILL ENCOUNTER STRONG (30-40 KTS) VERTICAL WIND SHEAR
AND LOW (24-25 DEGREE CELSIUS) SST AS IT MOVES INTO THE PATH OF AN
APPROACHING MID-LATITUDE TROUGH, WHERE UPPER-LEVEL WESTERLIES WILL
ALSO SUPPRESS DIVERGENCE ALOFT. THE INCREASINGLY UNFAVORABLE
ENVIRONMENT AND MID-LATITUDE TROUGH WILL CONTINUE THE WEAKENING
TREND AND INDUCE EXTRATROPICAL TRANSITION BEGINNING AT TAU 48. TC
17S IS EXPECTED TO COMPLETE EXTRATROPICAL TRANSITION AT TAU 72.
NUMERICAL MODEL GUIDANCE REMAINS IN GOOD AGREEMENT, EXCEPT NAVGEM AS
THE EASTERNMOST OUTLIER LATER IN THE FORECAST, THEREFORE, THERE IS
HIGH CONFIDENCE IN THE JTWC FORECAST TRACK. MAXIMUM SIGNIFICANT WAVE
HEIGHT AT 060000Z IS 27 FEET. NEXT WARNINGS AT 060900Z, 061500Z,
062100Z AND 070300Z.//
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Rédigé par PATRICK HOAREAU le Wednesday, March 6th 2019 à 07:14