WDPN33 PGTW 050300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 12W (HAIKUI) WARNING NR 
10//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM 12W (HAIKUI), LOCATED APPROXIMATELY 80 NM EAST-
NORTHEAST OF KADENA AB, OKINAWA, JAPAN, HAS TRACKED WEST-
NORTHWESTWARD AT 09 KNOTS OVER THE PAST SIX HOURS. ANIMATED 
MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS PERSISTENT CENTRALIZE 
CONVECTION OVER THE LOW LEVEL CIRCULATION CENTER (LLCC) WITH 
PREDOMINANTLY THE DEEPEST CONVECTION LOCATED WITHIN THE SOUTHERN 
SEMI-CIRCLE. THE RADAR DEPICTION FROM OKINAWA SHOWS A MULTITUDE OF 
BANDS CROSSING OVER OKINAWA AND INTO THE EAST CHINA SEA. UPPER LEVEL 
ANALYSIS INDICATES TS 12W IS LOCATED TO THE SOUTH OF A DEEP LAYERED 
SUBTROPICAL RIDGE (STR) AND IS TRACKING ALONG ITS SOUTHERN 
PERIPHERY. ANIMATED WATER VAPOR IMAGERY AND TOTAL PRECIPITABLE WATER 
CONTINUE TO INDICATE TS 12W IS PARTIALLY ENCAPSULATED BY A WEAKENING 
RIBBON OF DRY AIR ALONG THE WESTERN AND SOUTHERN SEMI-CIRCLES. 
ADDITIONALLY, THE VERTICAL WIND SHEAR (VWS) REMAINS LOW (05 TO 10 
KNOTS). THE OUTFLOW REMAINS MARGINAL OVER THE ENTIRE SYSTEM.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS 
PROGNOSTIC REASONING MESSAGE.
   B. TS 12W IS FORECAST TO MAINTAIN A WEST-NORTHWESTWARD TRACK 
ALONG THE SOUTHERN PERIPHERY OF THE STR THROUGH TAU 72. 
INTENSIFICATION WILL REMAIN SLOW AND STEADY UNDER WEAK VWS AND WARM 
(28-30C) SEA SURFACE TEMPERATURES TO A PEAK OF 75 KNOTS BY TAU 72. 
MODEL GUIDANCE HAS SLOWLY COME INTO BETTER AGREEMENT THROUGH TAU 72, 
WITH NGPS, WBAR, AND GFDN SHOWING A TRACK INTO THE EAST CHINA SEA BY 
TAU 72. THERE IS HIGH CONFIDENCE IN THE TRACK FORECAST THROUGH TAU 
72.
   C. TS 12W IS EXPECTED TO MAKE LANDFALL AS A SIGNIFICANT TYPHOON 
SHORTLY AFTER TAU 72. DISSIPATION WILL BEGIN SHORTLY AFTER TAU 72 AS 
FRICTIONAL DRAG INCREASES. MODEL GUIDANCE HAS BEEN IMPROVING, 
HOWEVER THERE CONTINUES TO BE A LARGE SPREAD AFTER TAU 72. WITH THE 
EXCEPTION OF NGPS, WBAR AND GFDN DISCUSSED EARLIER, THE REMAINDER OF 
THE GUIDANCE KEEPS TS 12W OVER LAND. A RELATIVELY SHALLOW MID-
LATITUDE TROUGH WILL INTERACT WITH THE STEERING STR OVER THE NEXT 
TWO TO THREE DAYS BUT AT THIS TIME THE MAGNITUDE OF INTERACTION 
REMAINS UNCLEAR. ADDITIONALLY, ANOTHER SHALLOW MID-LATITUDE TROUGH 
WILL AGAIN INTERACT WITH THE STR BY THE FOUR TO FIVE DAY MARK, WHICH 
IS DEPICTED WITHIN THE FORECAST BY THE SLIGHT NORTHWESTWARD TRACK AT 
TAU 120. DUE TO THE HIGH LEVEL OF UNCERTAINTY, CONFIDENCE IN THE 
EXTENDED TRACK FORECAST IS LOW.//
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