meteo





PODUL(13W) over South China Sea within 12h, landfall southern Hainan in72h with 50knots winds


Warning 5/JTWC


Météo974

M974World

WESTERN NORTH PACIFIC

TD PODUL(13W)
As of 12:00 UTC Aug 27, 2019:
Location: 16.0°N 123.2°E
Maximum Winds: 30 kt ( 55km/h)
Gusts: 40 kt ( 75km/h)
Minimum Central Pressure: 1002 mb

WDPN31 PGTW 271500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 13W (PODUL)
WARNING NR 05//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL DEPRESSION (TD) 13W (PODUL), LOCATED APPROXIMATELY 153
NM NORTHEAST OF MANILA, PHILIPPINES, HAS TRACKED WEST-NORTHWESTWARD
AT 17 KNOTS (KTS) OVER THE PAST SIX HOURS. ANIMATED ENHANCED
INFRARED (EIR) SATELLITE IMAGERY DEPICTS A BROAD CIRCULATION WITH
FLARING DEEP CONVECTION NEAR THE CENTER AND SUSTAINED CONVECTION
ALONG THE WESTERN HALF OF THE CIRCULATION. THERE IS POOR CONFIDENCE
IN THE INITIAL POSITION BASED ON THE EIR AND EXTRAPOLATION FROM A
271000Z SSMIS 37 GHZ MICROWAVE IMAGE THAT DEPICTED A NOTCH FEATURE.
A 271200Z METOP-A ASCAT PASS CAPTURED WINDS ALONG THE EASTERN
PERIPHERY TO SHOW A BROAD AREA OF 15-20 KT WINDS AND A REGION OF 25-
30 KT WINDS ABOUT 200 NM NORTH OF THE CENTER. ALTHOUGH THIS PASS
FAILED TO CAPTURE THE LOW LEVEL CIRCULATION CENTER AND THE WESTERN
PERIPHERY OF THE SYSTEM, IT PROVIDES AN IDEA OF THE OVERALL WIND
FIELD STRUCTURE. THE CURRENT INTENSITY OF 30 KNOTS IS BASED ON MULTI-
AGENCY DVORAK ESTIMATES OF T2.0 (30 KNOTS). THE ENVIRONMENT IS
MARGINAL OVERALL WITH FAIRLY STRONG (15-25 KT) VERTICAL WIND SHEAR
(VWS) BEING OFFSET BY FAVORABLE EQUATORWARD AND WESTWARD OUTFLOW AND
WARM SEA SURFACE TEMPERATURE (29-30 CELSIUS). TD 13W IS TRACKING
ALONG THE SOUTHERN PERIPHERY OF A SUBTROPICAL RIDGE (STR).
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. THROUGH TAU 72, TD 13W SHOULD CONTINUE TO TRACK WESTWARD TO
WEST-NORTHWESTWARD ALONG THE SOUTHERN PERIPHERY OF THE STR, MAKE
LANDFALL ALONG LUZON AROUND TAU 6, RE-EMERGE OVER THE SOUTH CHINA
SEA (SCS) PRIOR TO TAU 12, AND MAKE A SECOND LANDFALL ALONG SOUTHERN
HAINAN AROUND TAU 72. THE RAPID TRANSIT OF LUZON SHOULD MINIMIZE
WEAKENING DUE TO LAND INTERACTION AND, UNDER MARGINAL ENVIRONMENTAL
CONDITIONS OVER THE SCS, GRADUAL INTENSIFICATION SHOULD ALLOW THE
SYSTEM TO REACH 50 KTS BY TAU 48. THERE IS HIGH UNCERTAINTY IN THE
INTENSITY FORECAST DUE TO CONTINUED COMPETING ENVIRONMENTAL
INFLUENCES. DESPITE FAIR AGREEMENT IN THE AVAILABLE MODEL GUIDANCE,
THERE IS LOW CONFIDENCE IN THIS PORTION OF THE JTWC TRACK FORECAST
DUE TO HIGH UNCERTAINTY IN THE INITIAL POSITION.
   C. AFTER TAU 72, A SHORTWAVE TROUGH OVER EASTERN CHINA IS
EXPECTED TO WEAKEN THE STR AND ALLOW THE SYSTEM TO TURN MORE
POLEWARD PRIOR TO MAKING LANDFALL NEAR HANOI, VIETNAM. THE INTENSITY
IS FORECAST TO WEAKEN GRADUALLY DURING THIS PERIOD DUE TO LAND
INTERACTION WITH VIETNAM AND HAINAN BUT UNCERTAINTY IN THE INTENSITY
FORECAST IS HIGH AS THE OUTFLOW MAY IMPROVE SIGNIFICANTLY DEPENDING
ON TIMING OF TROUGH PASSAGE. AVAILABLE DYNAMIC MODEL GUIDANCE IS IN
POOR AGREEMENT AS SOME MODELS (NAVGEM, GFS) DEPICT A SHARP POLEWARD
TURN OVER HAINAN WHILE OTHERS SHOW LITTLE TO NO INFLUENCE FROM THE
TROUGH PASSAGE. THE JTWC TRACK FORECAST CONTINUES TO SHOW A SLIGHT
POLEWARD TURN BUT IT IS POSSIBLE THAT SUBSEQUENT FORECASTS WILL
MAINTAIN THE WESTWARD TRACK, IF THE BULK OF GUIDANCE CONTINUES TO
SHOW A WESTWARD SOLUTION. BASED ON HIGH UNCERTAINTY IN THE INFLUENCE
OF THE SHORTWAVE TROUGH, THERE IS LOW CONFIDENCE IN THE EXTENDED
PORTION OF THE JTWC FORECAST TRACK.//
NNNN



Rédigé par PATRICK HOAREAU le Mardi 27 Août 2019 à 21:34