Tropical Storm MAYSAK Advisory Sex, 03-04

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 04W (MAYSAK) WARNING NR 29//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   ANIMATED MULTISPECTRAL SATELLITE IMAGERY DEPICTS AN ELONGATING
CENTRAL CORE STRUCTURE WITH CONVECTION BEING SHEARED TO THE
NORTHEAST DUE TO HIGH (30 KNOT) SOUTHWESTERLY VERTICAL WIND SHEAR
(VWS) ASSOCIATED WITH A MID-LATITUDE TROUGH TO THE WEST. A 02222Z
SSMIS 89GHZ MICROWAVE IMAGE SHOWS A SMALL MICROWAVE EYE FEATURE
WHILE THE 37GHZ IMAGE HAS ALMOST COMPLETELY LOST THE MICROWAVE EYE
FEATURE. BOTH IMAGES SHOW THAT THE CONVECTION IS DISPLACED TO THE
NORTHEAST WITH DRY AIR WRAPPING AROUND THE SOUTHERN PERIPHERY FROM
THE WEST. UPPER LEVEL ANALYSIS INDICATES SIGNIFICANT DRY AIR
ADVECTION INTO THE PHILIPPINE SEA BY THE AFOREMENTIONED TROUGH.
THESE FACTORS ARE OFFSETTING THE VIGOROUS POLEWARD OUTFLOW THAT IS
EVIDENT ON THE WATER VAPOR LOOP. THE INITIAL POSITION IS BASED ON
THE MICROWAVE EYE FEATURE WITH GOOD CONFIDENCE. THE INITIAL
INTENSITY IS HEDGED SLIGHTLY LOWER THAN DVORAK CURRENT INTENSITY
ESTIMATES OF T5.0 (90 KNOTS) TO REFLECT THE SYSTEM'S WEAKENING
STRUCTURE AND IS SUPPORTED BY A RECENT SATCON INTENSITY ESTIMATE OF
85 KNOTS. TY MAYSAK IS TRACKING ALONG THE SOUTHWESTERN PERIPHERY OF
THE DEEP LAYERED SUBTROPICAL RIDGE (STR) LOCATED TO THE NORTHEAST.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TY 04W WILL CONTINUE TRACKING NORTHWESTWARD THROUGH TAU 24
UNDER THE INFLUENCE OF THE STEERING STR. BETWEEN TAU 24 AND 36, TY
MAYSAK WILL TRACK SLIGHTLY WESTWARD AS THE SHORTWAVE TROUGH
PROPAGATES EAST AND AN EXTENSION OF THE STEERING STR BUILDS IN NORTH
OF THE SYSTEM. BEYOND TAU 36, THE SYSTEM WILL TURN NORTHWESTWARD
AGAIN AS THE STR REORIENTS TO ITS ORIGINAL POSITION TO THE
NORTHEAST. UPPER LEVEL ENVIRONMENTAL CONDITIONS WILL CONTINUE TO
DETERIORATE AS VWS INCREASES THROUGH TAU 36 AND UPPER LEVEL
DIVERGENCE DECREASES. AS THE UPPER LEVEL TROUGH MOVES OUT OF THE
REGION VWS WILL DROP BACK TO MARGINAL LEVELS (15-20 KNOTS), CAUSING
A SLOWER WEAKENING JUST PRIOR TO LANDFALL. BEYOND TAU 48, THE
WEAKENING WILL BE ENHANCED AGAIN DUE TO FRICTIONAL EFFECTS AS THE
SYSTEM MAKES LANDFALL AND TRACKS OVER CENTRAL LUZON.
   C. IN THE EXTENDED TAUS, TY MAYSAK WILL FURTHER WEAKEN IN THE
SOUTH CHINA SEA DUE TO HIGH VWS AND POOR OUTFLOW ALOFT. NEAR TAU 96,
A STRONG NORTHEASTERLY SURGE THROUGH THE TAIWAN STRAIT WILL FORCE
THE WEAKENED SYSTEM TO BEND WESTWARD. IN ADDITION TO A POOR UPPER
LEVEL ENVIRONMENT, TY 04W WILL ALSO ENCOUNTER SST BELOW 26 CELSIUS.
DYNAMIC GUIDANCE REMAINS IN GOOD AGREEMENT, LENDING HIGH CONFIDENCE
TO THE JTWC FORECAST TRACK.//
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