WDPN31 PGTW 271500
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 26W (NIDA) WARNING NR 
23//
RMKS/
1. FOR METEOROLOGISTS.
2. 12 HOUR SUMMARY AND ANALYSIS.
    A. SUPER TYPHOON (STY) 26W (NIDA) HAS TRACKED NORTH-
NORTHWESTWARD ALONG THE WESTERN PERIPHERY OF THE SUBTROPICAL 
STEERING RIDGE AT 05 KNOTS OVER THE PAST SIX HOURS. ALTHOUGH STY 
NIDA HAS DISPLAYED AN ASYMMETRICAL CONVECTIVE STRUCTURE IN ANIMATED 
INFRARED IMAGERY OVER THE LAST 12 HOURS, THE SYSTEM CONTINUES TO 
HAVE A WELL-DEFINED 30-NM EYE WHILE A 270920Z SSMIS MICROWAVE IMAGE 
SHOWS CONSTRICTION OF THE INNER EYEWALL (COMPARED TO THE 261037Z 
TRMM IMAGE) AND RE-DEVELOPMENT OF A CONCENTRIC OUTER EYEWALL. 
ACCORDINGLY, THE SYSTEM HAS MAINTAINED A 130-KNOT INTENSITY OVER THE 
LAST 12 HOURS AND THE CURRENT INTENSITY IS SUPPORTED BY DVORAK 
ESTIMATES FROM PGTW, KNES (127 KNOTS) AND RJTD (140 KNOTS). UPPER-
LEVEL ANALYSIS INDICATES THE SYSTEM IS STILL IN AN AREA OF MINIMAL 
VERTICAL WIND SHEAR WITH AN ANTICYCLONE ALOFT, WHICH IS PROVIDING 
STRONG RADIAL OUTFLOW. ADDITIONALLY, ANIMATED WATER VAPOR IMAGERY 
ILLUSTRATES THE SYSTEM'S STRONG POLEWARD OUTFLOW INTO THE MID-
LATITUDE WESTERLIES.
3. FORECAST REASONING.
    A. THE FORECAST REASONING HAS NOT CHANGED SINCE THE LAST 
PROGNOSTIC REASONING BULLETIN.
    B. STY NIDA'S NORTHWESTWARD MOVEMENT SHOULD BE TEMPORARY AS THE 
271200Z UPPER-AIR SOUNDING FROM CHICHI JIMA CONTINUES TO SHOW STRONG 
MID-LEVEL WESTERLIES. OVER THE NEXT 24 HOURS, NIDA IS EXPECTED TO 
MAINTAIN A STRONG TYPHOON INTENSITY AND CREST THE SUBTROPICAL RIDGE 
AXIS AS IT TURNS TO THE NORTHEAST. THE NUMERICAL MODEL GUIDANCE IS 
IN GOOD AGREEMENT WITH THIS RECURVATURE SCENARIO. HOWEVER, THE JGSM 
AND ECMWF SOLUTIONS DEPICT A WESTWARD TRACK THAT CAN ONLY BE 
EXPLAINED BY ERRONEOUS INITIALIZATION OF STY NIDA IN THE MODELS AS A 
MUCH WEAKER TROPICAL CYCLONE. THROUGH TAU 48, THE SYSTEM WILL 
GRADUALLY WEAKEN IN INTENSITY AS THE FAVORABLE ENVIRONMENT STARTS TO 
DETERIORATE.
    C. AFTER TAU 48, NIDA WILL BEGIN TO ACCELERATE AND RAPIDLY 
WEAKEN AS IT FACES INCREASING VERTICAL WIND SHEAR AND COLDER SEA 
SURFACE TEMPERATURES. BY TAU 72, THE SYSTEM SHOULD BEGIN TO INTERACT 
WITH THE BAROCLINIC ZONE AND BY TAU 96 NIDA WILL COMPLETE 
EXTRATROPICAL TRANSITION. THIS FORECAST IS FASTER THAN THE JTWC 
CONSENSUS AT DAYS THREE AND FOUR DUE TO THE CONSENSUS BEING SKEWED 
BY THE ECMWF SOLUTION.//
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