meteo





TD 13W: landfall over Eastern Luzon within 12h. Intensification over the South China Sea


Warning 3/JTWC


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WESTERN NORTH PACIFIC

TD 13W
As of 00:00 UTC Aug 27, 2019:
Location: 14.8°N 126.0°E
Maximum Winds: 30 kt ( 55km/h)
Gusts: 40 kt ( 75km/h)
Minimum Central Pressure: 1000 mb

WDPN31 PGTW 270300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 13W (THIRTEEN)
WARNING NR 03//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL DEPRESSION (TD) 13W (THIRTEEN), LOCATED APPROXIMATELY 290
NM EAST OF MANILA, PHILIPPINES, HAS TRACKED WEST-NORTHWESTWARD AT 20
KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY DEPICTS A PARTIALLY-EXPOSED LOW-LEVEL CIRCULATION WITH
FLARING DEEP CONVECTION ACROSS THE WESTERN SEMICIRCLE. A 262248Z
SSMIS 37GHZ MICROWAVE IMAGE INDICATES FRAGMENTED BANDING WRAPPING
INTO A BROAD LOW LEVEL CIRCULATION CENTER, THEREFORE, THERE IS POOR
CONFIDENCE IN THE CURRENT POSITION. THE CURRENT INTENSITY IS ASSESSED
AT 30 KNOTS BASED ON A MULTI-AGENCY DVORAK ESTIMATES OF T1.0-2.0
(25-35 KNOTS) AND A 270100Z ADT ESTIMATE OF 32 KNOTS. ENVIRONMENTAL
ANALYSIS REVEALS A MARGINALLY FAVORABLE ENVIRONMENT WITH MODERATE TO
STRONG (20-30) VERTICAL WIND SHEAR OFFSET BY MODERATELY FAVORABLE
DIFFLUENCE ALOFT AND WARM SST (28-30C). TD 13W IS TRACKING WESTWARD
ALONG THE SOUTHERN PERIPHERY OF A SUBTROPICAL RIDGE (STR) ENTRENCHED
TO THE NORTH.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. IN THE NEAR TERM, TD 13W WILL TRACK WEST-NORTHWESTWARD MAKING
LANDFALL OVER EASTERN LUZON NEAR TAU 12. DUE TO THE MARGINALLY
FAVORABLE ENVIRONMENT, THE SYSTEM IS EXPECTED TO INCREASE TO MINIMAL
TROPICAL STORM STRENGTH (35 KNOTS) AT TAU 12 BEFORE LANDFALL. TD 13W
IS EXPECTED TO MAINTAIN INTENSITY AS IT CROSSES LUZON DUE TO LAND
INTERACTION EFFECTS AND THEN IS EXPECTED TO CONTINUE TO INTENSIFY TO
50 KNOTS BY TAU 72. THERE IS HIGH UNCERTAINTY IN THE INTENSITY AS IT
REDEVELOPS WEST OF LUZON DUE TO THE SUSTAINED MODERATE SHEAR,
MODERATE UPPER LEVEL DIVERGENCE AND BROAD NATURE OF THE SYSTEM. THE
SYSTEM IS EXPECTED TO CONTINUE TRACKING WESTWARD TO
WEST-NORTHWESTWARD UNDER THE STEERING INFLUENCE OF THE STR POSITIONED
TO THE NORTH THROUGH TAU 72.
   C. AFTER TAU 72, A DEEP SHORTWAVE TROUGH IS FORECAST TO DIG OVER
EASTERN CHINA WHICH WILL WEAKEN THE STR AND ALLOW THE SYSTEM TO TURN
MORE POLEWARD TOWARD HAINAN ISLAND. THE SYSTEM IS EXPECTED TO
MAINTAIN INTENSITY THROUGH TAU 96 AS IT PASSES ALONG THE SOUTHERN
EDGE OF HAINAN. AFTER TAU 96, TD 13W SHOULD STEER NORTHWESTWARD AS IT
TRANSITIONS TO THE WESTERN STR WITH SLIGHT WEAKENING AS IT BEGINS TO
INTERACT WITH VIETNAM. THE DYNAMIC MODEL GUIDANCE IS IN FAIR
AGREEMENT WITH TWO OUTLIERS (NAVGEM AND GFS), THEREFORE, THERE
IS LOW CONFIDENCE IN THE FORECAST TRACK.//
NNNN


27/00UTC
27/00UTC

26/1958UTC
26/1958UTC

TRACK AND INTENSITY GUIDANCE
TRACK AND INTENSITY GUIDANCE
Rédigé par PATRICK HOAREAU le Mardi 27 Août 2019 à 07:24