Intensifying Typhoon Phanfone bearing down on Tacloban/PH. Landfall: shortly before 12h



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TY 30W( PHANFONE) WESTERN NORTH PACIFIC
As of 00:00 UTC Dec 24, 2019:

Location: 10.8°N 127.6°E
Maximum Winds: 70 kt ( 130km/h)
Gusts: 85 kt ( 160km/h)

Minimum Central Pressure:  mb
CATEGORY US: 1

WDPN31 PGTW 240300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 30W (PHANFONE)
WARNING NR 010//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON (TY) 30W (PHANFONE), LOCATED APPROXIMATELY 448 NM EAST-
SOUTHEAST OF MANILA, PHILIPPINES, HAS TRACKED WESTWARD AT 16 KNOTS
OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY
REVEALS AN AREA OF SUSTAINED DEEP CENTRAL CONVECTION OBSCURING THE
LOW LEVEL CIRCULATION CENTER. THERE IS GOOD CONFIDENCE IN THE
INITIAL POSITION, WHICH IS SUPPORTED BY A DEVELOPING MICROWAVE EYE
IN THE 232311Z GMI 37GHZ IMAGE. THE INITIAL INTENSITY IS ASSESSED
AT 70 KTS, AVERAGING BETWEEN A DVORAK ESTIMATE OF T4.0 (65 KTS) BY
PGTW/RJTD AND AN ESTIMATE OF T4.5 (77 KTS) BY KNES, A 240040Z ADT
OF 4.4 (74 KTS), AND A 232102Z SATCON ESTIMATE OF 74 KTS. THE
ENVIRONMENT IS FAVORABLE FOR CONTINUED DEVELOPMENT WITH LOW (10-15
KT) VERTICAL WIND SHEAR (VWS), GOOD POLEWARD AND EQUATORWARD
OUTFLOW AND WARM (28-29 CELSIUS) SEA SURFACE TEMPERATURES (SSTS).
TY 30W IS TRACKING ALONG THE SOUTHERN PERIPHERY OF A SUBTROPICAL
RIDGE (STR).
3. FORECAST REASONING.
   A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY
FROM THE PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TY 30W WILL TRACK GENERALLY WEST-NORTHWESTWARD THROUGHOUT
THE FORECAST. THE ENVIRONMENT REMAINS FAVORABLE ALLOWING TY 30W TO
INTENSIFY FURTHER PRIOR TO MAKING LANDFALL JUST BEFORE TAU 12.
LAND INTERACTION WILL CAUSE THE SYSTEM TO WEAKEN, THEREFORE THE
INTENSITY IS FORECAST TO BE 75 KTS AT TAU 12. HOWEVER THERE IS
POTENTIAL FOR TY 30W TO BE STRONGER THAN 75 KTS PRIOR TO MAKING
LANDFALL. BETWEEN TAUS 12 AND 36 THE FAVORABLE ENVIRONMENT IS
EXPECTED TO PARTIALLY OFFSET THE LAND INTERACTION ALLOWING THE
SYSTEM TO DECREASE ONLY 5 KTS TO 70 KTS AT TAU 24 AND THEN
MAINTAIN INTENSITY. ONCE TY 30W EMERGES IN THE SOUTH CHINA SEA IT
WILL INCREASE TO A MAXIMUM INTENSITY OF 80 KTS AT TAU 48. DUE TO
THE COMPLICATED NATURE OF THE LAND INTERACTION IN THIS FORECAST
THERE IS HIGH UNCERTAINTY IN THE INTENSITY FORECAST. HOWEVER,
THERE IS STRONG AGREEMENT IN THE MODEL TRACK GUIDANCE THROUGH TAU
36 LENDING HIGH CONFIDENCE TO THIS PORTION OF THE JTWC TRACK
FORECAST. AFTER TAU 36, THE SPREAD INCREASES SLIGHTLY, THEREFORE
THERE IS FAIR CONFIDENCE IN THIS PORTION OF THE JTWC TRACK
FORECAST.
   C. AFTER TAU 72, TY 30W WILL BEGIN TO ENCOUNTER DECREASING
SSTS, INCREASING VWS AND RELATIVELY COOL, DRY AIR. AS A RESULT,
THE INTENSITY IS EXPECTED TO FALL RAPIDLY, REACHING 30 KTS BY TAU
120. FURTHERMORE, THE SYSTEM WILL SLOW AS IT APPROACHES A COL
BETWEEN THE STEERING STR AND A LESS PRONOUNCED STR TO THE WEST.
MODEL GUIDANCE SPREAD CONTINUES TO INCREASE FOR THIS PORTION OF
THE FORECAST, WITH NAVGEM BEING AN EXTREME NORTHEASTERLY OUTLIER.
THEREFORE, THE FORECAST TRACK FOLLOWS THE MORE WESTWARD TRACK WITH
THE MULTI-MODEL CONSENSUS, GFS, GFS ENSEMBLE, AND ECMWF.//
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24/00UTC
24/00UTC

TRACK AND INTENSITY GUIDANCE

Rédigé par PATRICK HOAREAU le Mardi 24 Décembre 2019 à 06:42