09UTC: OMA reduced to a 45knots cyclone, forecast to intensify gradually next 48hours


Warning 26/JTWC


2019 FEB 18 0955UTC SOUTH PACIFIC
My Remarks: struggling TC primarily due to up-welling of cooler seas. Forecast to slowly move back over warmer seas and peak near 65knots(CAT1 US) in 48H. High confidence in the forecast track over 48H and low afterward as models spread out significantly with two outliers: Navgen to the right and Ecmwf to the left.

TC #OMA #15P
This system is currently analysed as a 45knots TC.
WARNING 26/JTWC
Click on the TC graphic to read the Remarks for Warning 26 .
Satellite bulletins are to be found in the comments of this post on JTWC BIS.
As of 06:00 UTC Feb 18, 2019:
Location: 18.2°S 163.3°E
Maximum Winds: 45 kt ( 85km/h)
Gusts: 55 kt ( 100km/h)
Minimum Central Pressure: 989 mb
REMARKS:
180900Z POSITION NEAR 18.5S 163.1E.
TROPICAL CYCLONE (TC) 15P (OMA), LOCATED APPROXIMATELY 282 NM
NORTHWEST OF NOUMEA, NEW CALEDONIA, HAS TRACKED SOUTHWESTWARD AT 11
KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY SHOWS THE SYSTEM CONTINUING TO UNRAVEL AND WEAKEN AS
EVIDENCED BY WARMING CONVECTIVE TOPS AND EXPANDING FRAGMENTED RAIN
BANDS. HOWEVER, THE CYCLONE MAINTAINED A RAGGED BUT DEFINED LOW LEVEL
CIRCULATION LENDING HIGH CONFIDENCE TO THE INITIAL POSITION. THE
INITIAL INTENSITY IS BASED ON THE DVORAK ESTIMATE OF T3.0/45KTS FROM
PGTW AND REFLECTS THE WEAKENED CONVECTIVE SIGNATURE. UPPER LEVEL
ANALYSIS INDICATES TC 15P IS UNDER MODERATE (15-20 KNOT) VERTICAL
WIND SHEAR THAT IS PARTLY OFFSET BY EXCELLENT RADIAL OUTFLOW.
HOWEVER, THE SYSTEM IS STILL IN A POOL OF RELATIVELY COOL SEA
SURFACE TEMPERATURES (SSTS) AT 24-25 CELSIUS, A RESULT OF TC-INDUCED
UPWELLING. THE NET ENVIRONMENTAL EFFECT IS WEAKENING INTENSITY. TC
OMA WILL CONTINUE TO TRACK POLEWARD UNDER THE STEERING INFLUENCE OF
THE SUBTROPICAL RIDGE (STR) TO THE EAST. AFTER TAU 72, IT WILL ROUND
THE STR AXIS AND ACCELERATE SOUTHEASTWARD AHEAD OF AN APPROACHING
MID-LATITUDE TROUGH. A BRIEF PERIOD OF WARMING SSTS AND INCREASING
POLEWARD OUTFLOW WILL FUEL A MODEST INTENSIFICATION TO A PEAK OF 65
KNOTS BY TAU 48. AFTERWARD, INCREASING VWS AND COOLING SSTS WILL
ONCE AGAIN ERODE THE CYCLONE DOWN TO 45 KNOTS BY END OF FORECAST.
CONCURRENTLY, AROUND TAU 96, TC 15P WILL BEGIN EXTRA-TROPICAL
TRANSITION AND BY TAU 120 WILL TRANSFORM INTO A STORM-FORCE COLD
CORE LOW WITH AN EXPANDING WIND FIELD. NUMERICAL MODEL GUIDANCE IS
IN GOOD AGREEMENT UP TO TAU 48 THEN SPREADS OUT SIGNIFICANTLY
AFTERWARD. NOTABLE OUTLIERS INCLUDE NAVGEM TO THE RIGHT OF THE MODEL
ENVELOPE, AND ECMWF SUGGESTING A 180 DEGREE EQUATORWARD TRACK
REVERSAL AFTER TAU 72. IN VIEW OF THESE, THERE IS HIGH CONFIDENCE IN
THE JTWC TRACK FORECAST UP TO TAU 48 AND LOW CONFIDENCE AFTERWARD.
MAXIMUM SIGNIFICANT WAVE HEIGHT AT 180600Z IS 23 FEET. NEXT WARNINGS
AT 181500Z, 182100Z, 190300Z AND 190900Z.//
NNNN
Cheers,
Patrick Hoareau



2019 FEB 18 0920UTC
2019 FEB 18 0920UTC

2019 FEB 18 0820UTC
2019 FEB 18 0820UTC

2019 FEB 18 0830UTC
2019 FEB 18 0830UTC





Rédigé par PATRICK HOAREAU le Lundi 18 Février 2019 à 14:02