WDPN31 PGTW 111500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 22W (PRAPIROON) WARNING NR 
17//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON (TY) 22W (PRAPIROON), LOCATED APPROXIMATELY 415 NM SOUTH 
OF KADENA AIR BASE, OKINAWA, JAPAN, HAS BECOME QUASI-STATIONARY 
OVER THE PAST SIX HOURS. ANIMATED INFRARED SATELLITE IMAGERY (IR) 
AND AN 111132Z SSMIS 91GHZ MICROWAVE IMAGE DEPICT A WELL-DEFINED 
SYSTEM WITH TIGHTLY WRAPPED BANDING CONVECTION AND AN 18NM EYE. THE 
INITIAL INTENSITY IS BASED ON AN AVERAGE OF DVORAK INTENSITY 
ESTIMATES RANGING FROM 9O TO 102 KNOTS FROM PGTW, RJTD AND KNES. 
THERE IS HIGH CONFIDENCE IN THE INITIAL POSITION BASED ON THE EYE 
FEATURE IN THE IR AND SSMIS IMAGERY. UPPER-LEVEL ANALYSIS REVEALS 
RADIAL OUTFLOW CONTINUES BENEATH A POINT SOURCE ANTICYCLONE IN AN 
AREA OF LOW (05 TO 10 KNOT) VERTICAL WIND SHEAR (VWS) WITH STRONG 
POLEWARD OUTFLOW INTO THE WESTERLIES. TY 22W IS QUASI-STATIONARY IN 
A WEAK STEERING ENVIRONMENT BETWEEN A DEEP- LAYERED SUBTROPICAL 
RIDGE (STR) TO THE NORTHEAST AND A NEAR EQUATORIAL RIDGE TO THE 
SOUTHEAST.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE 
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TY 22W IS EXPECTED TO SLOWLY TRACK MORE POLEWARD DURING THE 
NEXT 12 HOURS AS THE SYSTEM REMAINS IN A WEAK STEERING ENVIRONMENT 
BETWEEN THE TWO AFOREMENTIONED RIDGES. AFTER TAU 12, TY 22W IS 
EXPECTED TO SLOWLY TAKE A MORE NORTHEASTERN TRACK AROUND THE 
WESTERN EXTENT OF THE STR AND CONTINUE ON THIS TRACK THROUGH TAU 
96. TY 22W WILL SLIGHTLY INTENSIFY DURING THE NEXT 12 HOURS IN A 
FAVORABLE ENVIRONMENT AND REMAIN NEAR 100KTS FOR THE NEXT 48 HOURS 
AS A SLIGHT DECREASE IN OCEAN HEAT CONTENT OFFSETS THE FAVORABLE 
UPPER-LEVEL ENVIRONMENT. AFTER TAU 48, AN INCREASE IN VERTICAL WIND 
SHEAR AND CONTINUED DECREASING OCEAN HEAT CONTENT SHOULD GRADUALLY 
WEAKEN THE SYSTEM. DYNAMIC MODEL GUIDANCE CONTINUES TO BE 
INCONSISTENT IN THE TIMING BETWEEN MEMBERS, WITH JGSM AND EGRR BOTH 
TAKING A SLOWER TRACK FURTHER TO THE WEST. GFDN REMAINS THE RIGHT 
MOST OUTLIER WITH THE FASTEST TRACK. GFS, NOGAPS AND ECMWF HAVE 
COME INTO FAIR AGREEMENT AND ARE CLOSE TO MULTI-MODEL CONSENSUS. 
THE JTWC TRACK FORECAST IS CLOSE TO CONSENSUS THROUGH TAU 72 DUE TO 
THE LARGE VARIANCE IN TIMING AMONG MEMBERS.
   C. AFTER TAU 72, TY 22W WILL CONTINUE TO SLOWLY TRACK NORTHEAST 
ALONG THE WESTERN PERIPHERY OF THE STR. BETWEEN TAU 96 AND TAU 120 
TY 22W WILL TAKE A MORE NORTHWARD TRACK AS THE STR RE-ORIENTS. AS 
TY 22W SLOWLY GAINS LATITUDE, A LESS FAVORABLE ENVIRONMENT IS 
PREDICTED, ALLOWING A GRADUAL WEAKENING. AFTER TAU 120, TY 22W 
SHOULD PICK UP SPEED AND TRACK MORE TOWARDS THE NORTHEAST AS THE 
STR BECOMES MORE ESTABLISHED. SPREAD IN DYNAMIC MODEL GUIDANCE 
REMAINS AFTER TAU 72, WITH MOST MODELS INDICATING A TURN TO THE 
NORTHWEST AFTER TAU 96 DUE TO THE RE-ORIENTING STR. MODELS DO SHOW 
THIS NORTHWEST TURN TO BE SHORT LIVED AND CONTINUE TO TRACK THE 
SYSTEM NORTHEAST AFTER TAU 120. THE JTWC FORECAST FAVORS CONSENSUS 
AND DOES NOT MAKE THE SHARP TURN TO THE NORTHWEST, JUST A SLOW 
TRACK POLEWARD, AS DEPICTED IN THE GFS SOLUTION. FORECAST 
CONFIDENCE REMAINS LOW DUE TO THE DISAGREEMENT ON TRACK SPEEDS AND 
THE WEAK STEERING ENVIRONMENT.//
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