meteo





PODUL(13W) now over the South China Sea and intensifying a bit


Warning 7/JTWC


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WESTERN NORTH PACIFIC

TS PODUL(13W)
As of 00:00 UTC Aug 28, 2019:
Location: 16.7°N 119.4°E
Maximum Winds: 35 kt ( 65km/h)
Gusts: 45 kt ( 85km/h)
Minimum Central Pressure: 999 mb

WDPN31 PGTW 280300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 13W (PODUL) WARNING NR 07//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 13W (PODUL), LOCATED APPROXIMATELY 640 NM EAST
OF DA NANG, VIETNAM, HAS TRACKED WESTWARD AT 18 KNOTS OVER THE PAST
SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) 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 MSI AND A 272235Z
SSMIS 91GHZ MICROWAVE IMAGE. THE CURRENT INTENSITY OF 35 KNOTS IS
BASED ON MULTI-AGENCY DVORAK ESTIMATES OF T2.0-2.5 (35 KNOTS) AND A
271725Z SATCON ESTIMATE OF 39 KNOTS. THE ENVIRONMENT IS MARGINAL
OVERALL WITH MODERATE TO STRONG (20-30 KT) VERTICAL WIND SHEAR (VWS)
BEING OFFSET BY MODERATELY FAVORABLE WESTWARD OUTFLOW AND WARM SEA
SURFACE TEMPERATURE (29-30 CELSIUS). TS 13W IS TRACKING ALONG THE
SOUTHWESTERN 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, TS 13W SHOULD CONTINUE TO TRACK WESTWARD TO
WEST-NORTHWESTWARD AS IT PASSES SOUTH OF A COL WHILE A SHORTWAVE
TROUGH PASSES TO THE NORTH. AFTERWARDS, TS 13W WILL TRANSIT ALONG THE
SOUTHERN PERIPHERY OF A SECOND STR CURRENTLY SITUATED OVER CHINA WITH
A SECOND LANDFALL IN VIETNAM AROUND TAU 72. THE SYSTEM WILL BE
LIMITED BY STRONG SHEAR AND POOR UPPER LEVEL DIVERGENCE, BUT TS 13W
IS EXPECTED TO GRADUALLY INTENSIFY TO 45 KTS BY TAU 48. THERE IS HIGH
UNCERTAINTY IN THE INTENSITY FORECAST DUE TO CONTINUED COMPETING
ENVIRONMENTAL INFLUENCES. DESPITE FAIR AGREEMENT IN THE MAJORITY OF
THE 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, TS 13W IS EXPECTED TO CONTINUE TRACKING ALONG THE
SOUTHERN PERIPHERY OF THE STR. THE INTENSITY IS FORECAST TO WEAKEN
GRADUALLY DURING THIS PERIOD DUE TO LAND INTERACTION WITH VIETNAM AND
LAOS, BUT UNCERTAINTY IN THE INTENSITY FORECAST IS HIGH AS THE
OUTFLOW MAY IMPROVE DEPENDING ON THE TRACK ACROSS THE SOUTH CHINA
SEA. AVAILABLE DYNAMIC MODEL GUIDANCE IS IN POOR AGREEMENT AS SOME
MODELS DEPICT A SHARP RECURVE WHILE OTHERS DEPICT A SUSTAINED
WEST-NORTHWESTWARD TRACK. THE STRAIGHT WEST-NORTHWESTWARD JTWC TRACK
FORECAST IS IN AGREEMENT WITH THE BULK OF THE MODEL GUIDANCE. BASED
ON HIGH UNCERTAINTY IN THE INFLUENCE OF THE APPROACHING SHORTWAVE
TROUGH, THERE IS LOW CONFIDENCE IN THE EXTENDED PORTION OF THE JTWC
FORECAST TRACK.//
NNNN


28/00UTC
28/00UTC


28/0124UTC
28/0124UTC

28/0124UTC
28/0124UTC

TRACK AND INTENSITY GUIDANCE
TRACK AND INTENSITY GUIDANCE
Rédigé par PATRICK HOAREAU le Mercredi 28 Août 2019 à 09:14