WDPN32 PGTW 230300
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 11W WARNING NR 25//
RMKS/
1. FOR METEOROLOGISTS.
2. 12 HOUR SUMMARY AND ANALYSIS.
      A. TYPHOON (TY) 11W (VAMCO), LOCATED APPROXIMATELY 805 NM 
NORTHWEST OF WAKE ISLAND, HAS TRACKED NORTH-NORTHWESTWARD AT 10 
KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL IMAGERY 
INDICATES THAT OVER THE PAST 03 HOURS VAMCO HAS RE-DEVELOPED AN EYE. 
DRY AIR HAS CONTINUED TO DEVELOP AROUND THE PERIPHERY OF TY 11W, 
HOWEVER, IT HAS NOT YET WRAPPED INTO THE LOW LEVEL CIRCULATION 
CENTER (LLCC). VAMCO HAS REMAINED ISOLATED FROM THE DRY AIR 
ENTRAINMENT, WITH A CONTINUED CONNECTION TO A TROPICAL AIR MASS TO 
THE SOUTHEAST. ANIMATED TOTAL PRECIPITABLE WATER IMAGERY INDICATES 
THAT A WEAK FINGER OF DRIER AIR HAS BEEN SLOWLY PROGRESSING ALONG 
THE SOUTHERN PERIPHERY OF VAMCO OVER THE PAST 12 HOURS WHICH WILL 
BEGIN TO SEPARATE VAMCO FROM THE TROPICAL AIR MASS. UPPER LEVEL 
ANALYSIS SHOWS THAT TY 11W IS LOCATED UNDER THE NORTHWESTERN 
QUADRANT OF AN UPPER LEVEL RIDGE, PROVIDING THE EASTERN OUTFLOW FOR 
VAMCO. AN UPPER LEVEL LOW TO THE WEST HAS CONTINUED TO PROVIDE A 
WEAK WESTWARD OUTFLOW OVER THE PAST 12 HOURS AS WELL. THE 
COMBINATION OF OUTFLOWS WITH A SOURCE OF MOISTURE ON THE SOUTH-
EASTERN QUADRANT, FAVORABLE OCEAN HEAT CONTENT (OHC) AND SEA SURFACE 
TEMPERATURES (SST) HAS ALLOWED VAMCO TO MAINTAIN ITS CURRENT 
INTENSITY.
3. FORECAST REASONING.
      A. THE FORECAST REASONING FOR TRACK PHILOSOPHY AND INTENSITY 
REMAINS UNCHANGED FROM THE PREVIOUS PROGNOSTIC REASONING.
      B. VAMCO WILL CONTINUE TO TRACK ALONG THE WESTERN PERIPHERY OF 
A MID-LATITUDE SUBTROPICAL RIDGE (STR), INCREASING IN TRACK SPEED AS 
IT BEGINS TO INTERACT WITH A MID-LATITUDE TROUGH, THAT IS CURRENTLY 
OVER NORTHERN JAPAN TRACKING EASTWARD. THE TROUGH WILL CAUSE A 
WEAKNESS IN THE STR ALLOWING A SHIFT IN THE TRACK TO THE EAST-
NORTHEAST AS THE STR RE-ORIENTS. VAMCO WILL BE CAPTURED BY THE MID-
LATITUDE WESTERLY FLOW CAUSING A MORE NORTHEASTWARD TRACK AROUND TAU 
36. TY 11W WILL START EXTRA-TROPICAL TRANSITION (ET) BY TAU 36 WITH 
COMPLETE ET BY TAU 48. DECREASING OHC AND SST VALUES, INCREASED 
VERTICAL WIND SHEAR, AND DRY AIR ENTRAINMENT WILL QUICKLY BEGIN TO 
WEAKEN TY 11W BETWEEN TAU 24 AND 36, SUPPORTING THE START OF THE ET 
PROCESS BY TAU 36. ALTHOUGH THE SYSTEM IS EXPECTED TO COMPLETED ET 
BY TAU 48, THE REMNANT LOW WILL REMAIN AS A STORM FORCE LOW AS IT 
CONTINUES TO TRACK NORTHEASTWARD. NUMERICAL MODEL GUIDANCE IS IN 
GOOD AGREEMENT WITH THE FORECAST TRACK AND ASSOCIATED INTENSITY.  
FORECAST TEAM: BRAVO.//
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