WDPN31 PGTW 270300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 22W (TWENTY-TWO) WARNING 
NR 001//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL DEPRESSION 22W (TWENTYTWO), LOCATED APPROXIMATELY 
1110 NM EAST OF MANILA, PHILIPPINES, HAS TRACKED WESTWARD AT 06 
KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY DEPICTS DISORGANIZED, FLARING CONVECTION OBSCURING A 
PARTIALLY EXPOSED LOW LEVEL CIRCULATION CENTER (LLCC). THE 
INITIAL POSITION IS PLACED WITH FAIR CONFIDENCE BASED ON THE 
SPIRAL BANDING AND LOW LEVEL FEATURES PRESENT IN THE MSI LOOP. 
THE INITIAL INTENSITY OF 25 KTS IS PLACE WITH FAIR CONFIDENCE 
BASED ON MULTI-AGENCY DVORAK CURRENT INTENSITY ESTIMATES OF 
T1.5 (25 KTS, PGTW AND RJTD) AS WELL AS FROM SCATTEROMETRY DATA
FROM A PARTIAL 272356Z ASCAT-A PASS THAT DEPICTS 20-25 KTS
WINDS ALONG THE NORTHWESTERN PERIPHERY OF THE SYSTEM. TD 22W IS
TRACKING ALONG THE SOUTHERN PERIPHERY OF A SUBTROPICAL RIDGE
POSITIONED TO THE NORTH AND THROUGH A FAVORABLE ENVIRONMENT FOR
FURTHER DEVELOPMENT WITH WARM (29-30 CELSIUS) SEA SURFACE 
TEMPERATURES (SST), LOW (5-10 KTS) VERTICAL WIND SHEAR (VWS),
HIGH (100-110 KJ/CM^2) AND ESTABLISHED POLEWARD AND EQUATORWARD
OUTFLOW ALOFT.
3. FORECAST REASONING.
   A. THIS IS THE FIRST PROGNOSTIC REASONING MESSAGE AND SETS
THE FORECAST PHILOSOPHY.
   B. TD 22W WILL CONTINUE TO TRACK GENERALLY WESTWARD THROUGH
TAU 48. DURING THIS TIME, CONTINUED FAVORABLE ENVIRONMENTAL
CONDITIONS WILL LEAD TO A GRADUAL INTENSIFICATION TO 45 KTS BY
TAU 48. AT THIS TIME, A REORIENTATION OF THE STEERING RIDGE WILL
LEAD TO A GENERALLY WEST-SOUTHWESTWARD TRACK AS AN EXTENSION OF
THE SUBTROPICAL RIDGE POSITIONED TO THE NORTHWEST BECOMES THE
PRIMARY STEERING MECHANISM. BETWEEN TAU 48 AND 72, THE SYSTEM IS
FORECAST TO FURTHER INTENSIFY, POSSIBLY RAPIDLY, DUE TO
CONTINUED LOW VWS, WARM SSTS AND CONTINUED UPPER LEVEL
DIVERGENCE, AND LEAD TO AN INTENSITY OF 80 KTS BY TAU 72. THE 
POTENTIAL FOR RAPID INTENSIFICATION IS DRIVEN BY INCREASING
OCEAN HEAT CONTENT VALUES AND MINIMAL VWS AND WILL LIKELY 
DEPEND ON THE TIMING OF THE RIDGE REPOSITIONING. NUMERICAL 
MODEL TRACK GUIDANCE IS IN TIGHT AGREEMENT WITH NAVGEM PROVIDING 
A SLIGHT POLEWARD BIAS AS COMPARED TO THE OTHER MEMBERS OF THE 
JTWC MULTI-MODEL CONSENSUS. THIS TIGHT AGREEMENT LENDS OVERALL 
GOOD CONFIDENCE IN THIS INITIAL PORTION OF THE JTWC FORECAST 
TRACK, WHICH IS LAID SLIGHTLY SOUTH OF THE MULTI-MODEL CONSENSUS.
   C. AFTER TAU 72, THE SYSTEM WILL CONTINUE TO TRACK GENERALLY 
WEST-SOUTHWESTWARD THROUGH TAU 96 AND FURTHER INTENSIFY TO 90
KTS BY THIS TIME DUE TO CONTINUED FAVORABLE ENVIRONMENTAL
CONDITIONS. SHORTLY AFTER TAU 96, TD 22W WILL MAKE LANDFALL
NORTH OF LEGAZPI, PHILIPPINES. AS THE STEERING RIDGE CONTINUES 
ITS REORIENTATION, THE FORECAST TRACK WILL BECOME GENERALLY 
NORTHWESTWARD BETWEEN TAU 96 AND TAU 120. INTERACTION WITH THE
UNDERLYING TERRAIN BETWEEN TAU 96 AND 120 WILL LEAD TO A 
WEAKENING IN INTENSITY TO 70 KTS BY TAU 120, AT WHICH TIME THE
SYSTEM CENTER WILL RETURN OVER WATER ALONG THE WEST COAST OF
LUZON. NUMERICAL MODEL GUIDANCE IS IN FAIR AGREEMENT WITH
A MAXIMUM TRACK SPREAD OF 440 NM AT TAU 120 AND LENDS FAIR 
AGREEMENT OVERALL IN THE ENTIRE JTWC FORECAST TRACK. //
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