Tropical Storm MAYSAK Advisory lun, 30-03

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 04W (MAYSAK) WARNING NR 13//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON (TY) 04W (MAYSAK), LOCATED APPROXIMATELY 526 NM EAST OF
YAP, HAS TRACKED WESTWARD AT 14 KNOTS OVER THE PAST SIX HOURS.
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS DEEP
CONVECTIVE SPIRAL BANDING WRAPPING INTO A CENTRAL CORE THAT REMAINS
SLIGHTLY ELONGATED. A 292320Z MHS 89GHZ MICROWAVE IMAGE SHOWS THE
MOST INTENSE BANDING TO THE NORTH AND WRAPPING INTO THE LOW LEVEL
CIRCULATION CENTER. UPPER LEVEL ANALYSIS INDICATES RADIAL OUTFLOW,
WHICH CAN BE SEEN ON WATER VAPOR IMAGERY, WITH 10 TO 20 KNOT
SOUTHEASTERLY VERTICAL WIND SHEAR (VWS). THE INITIAL POSITION IS
BASED ON THE AFOREMENTIONED MICROWAVE IMAGE AND THE MSI LOOP WITH
GOOD CONFIDENCE. THE INITIAL INTENSITY IS BASED ON AN ASSESSMENT OF
MULTI-AGENCY CURRENT INTENSITY ESTIMATES RANGING FROM 77 TO 90 KNOTS
AND SUPPORTED BY A SATCON INTENSITY ESTIMATE OF 83 KNOTS. TY MAYSAK
IS TRACKING ALONG THE SOUTHERN PERIPHERY OF THE DEEP LAYERED
SUBTROPICAL RIDGE (STR) TO THE NORTH.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
   B. TY 04W WILL CONTINUE TRACKING WESTWARD UNDER THE INFLUENCE OF
THE DOMINANT STEERING STR THROUGH TAU 48. TY MAYSAK IS FORECAST TO
CONTINUE INTENSIFYING OVER THE NEXT 48 HOURS DUE TO FAVORABLE UPPER
LEVEL CONDITIONS AND WARM SEA SURFACE TEMPERATURES (29 CELSIUS).
BEYOND TAU 48, TY 04W WILL TURN NORTHWESTWARD AS THE STEERING STR
WEAKENS AND REORIENTS DUE TO A PASSING SHORTWAVE TROUGH TO THE
NORTH. DURING THIS TIME, THE TYPHOON WILL ENCOUNTER INCREASED VWS AS
IT GAINS LATITUDE AND BEGIN ITS WEAKENING TREND.
   C. NEAR TAU 96, THE SHORTWAVE TROUGH WILL MOVE DOWNSTREAM FROM
THE STEERING STR CAUSING THE STR TO BUILD BACK IN NORTH OF THE
SYSTEM, CREATING A WEST-NORTHWESTWARD TRACK. AS TY 04W CONTINUES TO
GAIN LATITUDE IT WILL WEAKEN IN RESPONSE TO INCREASED VWS (20-25
KNOT). THERE IS NOW A SLIGHT BIFURCATION IN DYNAMIC MODEL GUIDANCE
NEAR TAU 72. COAMPS-TC AND GFDN TRACK A WEAKER SYSTEM MUCH FASTER
AND ON A WESTWARD TRACK INTO THE CENTRAL PHILIPPINES. THE REMAINING
GUIDANCE IS STILL IN TIGHT AGREEMENT ON A NORTHWESTWARD TRACK
TOWARDS LUZON. BASED ON THE CURRENT INTENSITY FORECAST, THE NORTHERN
TRACK IS MORE FEASIBLE AND, AS SUCH, THERE IS STILL HIGH CONFIDENCE
IN THE JTWC TRACK FORECAST.//
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