WDPN33 PGTW 191500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 25W (NEOGURI) WARNING NR 
005//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 24.7N 159.0E
   INITIAL INTENSITY: 60 KTS
   GEOGRAPHIC REFERENCE: 1184 NM EAST-SOUTHEAST OF YOKOSUKA, JAPAN
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 13 KTS
   SIGNIFICANT WAVE HEIGHT: 22 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TROPICAL
STORM 25W (NEOGURI) WITH DEEP CONVECTION ENTIRELY OBSCURING THE
LLCC AND COMPACT SPIRAL BANDING TIGHTLY WRAPPING INTO THE CENTER. A
191022Z METOP-C ASCAT PASS REVEALED 50-55 KNOT WINDS IN CLOSE
PROXIMITY TO THE ASSESSED CENTER. THE RADIUS OF MAX WINDS HAS
SIGNIFICANTLY SHRUNK OVER THE PAST 12 HOURS AND IS NOW ABOUT 20 NM.
25W HAS ALSO BEEN ANALYZED TO HAVE RAPIDLY INTENSIFIED FROM 30 KTS
24 HOURS AGO, TO 60 KTS NOW. ENVIRONMENTAL ANALYSIS INDICATES THAT
25W IS IN A HIGHLY FAVORABLE ENVIRONMENT CHARACTERIZED BY STRONG
RADIAL OUTFLOW ALOFT, LOW (5-10 KTS) VERTICAL WIND SHEAR, AND WARM
(29-30 C) SEA SURFACE TEMPERATURES. THE INITIAL POSITION IS
PLACED WITH MEDIUM CONFIDENCE BASED ON EXTRAPOLATION FROM THE
AFOREMENTIONED ASCAT IMAGE. THE INITIAL INTENSITY OF 60 KTS IS
ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE SAME ASCAT IMAGE ALONG
WITH THE AGENCY DVORAK AND OBJECTIVE INTENSITY ESTIMATES LISTED
BELOW.

INITIAL WIND RADII BASIS: 191022Z METOP-C ASCAT SCATTEROMETER DATA 

CURRENT STEERING MECHANISM: SOUTHWESTERN PERIPHERY OF A SUBTROPICAL
RIDGE CENTERED FAR TO THE NORTHEAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.0 - 65 KTS
   RJTD: T3.5 - 55 KTS
   RCTP: T3.5 - 55 KTS
   KNES: T4.5 - 77 KTS
   CIMSS ADT: 51 KTS AT 191200Z
   CIMSS AIDT: 48 KTS AT 191200Z
   CIMSS D-PRINT: 60 KTS AT 191200Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE
   VWS: 5-10 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG RADIAL

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   INITIAL INTENSITY: MEDIUM
   INITIAL WIND RADII: MEDIUM

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.

FORECAST DISCUSSION: 25W IS FORECAST TO TRACK NORTHWESTWARD, ALONG
THE SOUTHWESTERN PERIPHERY OF THE SUBTROPICAL RIDGE THROUGH TAU 48.
NEAR TAU 48, THE SYSTEM WILL BEGIN TO ROUND THE WESTERN EXTENT OF
THE RIDGE, CHANGING THE TRAJECTORY NORTHWARD. A NORTHEASTWARD TRACK
IS EXPECTED TO ENSUE FROM TAU 72 ONWARD AS THE VORTEX RUNS ALONG
THE NORTHWESTERN PERIPHERY OF THE RIDGE AND TRACKS POLEWARD. THERE
CONTINUES TO BE SOME UNCERTAINTY REGARDING THE RECURVE. MODELS HAVE
STARTED TO AGREE MORE ON A TRADITIONAL RECURVE SCENARIO THOUGH.
AFTER AN UPPER-LEVEL TROUGH BREAKS DOWN THE RIDGE, THERE IS A
SECOND RIDGE THAT PROPAGATES EASTWARD BEHIND THE FIRST, WHICH COULD
POTENTIALLY KEEP 25W FROM TRACKING FURTHER POLEWARD, AND INSTEAD,
OUT WESTWARD.  REGARDING INTENSITY, 25W IS FORECAST TO CONTINUE
INTENSIFYING OVER THE NEXT 72 HOURS TO A PEAK OF 105 KTS BEFORE
BEGINNING TO RECURVE. SHEAR AND SEA SURFACE TEMPERATURES ARE
EXPECTED TO REMAIN HIGHLY CONDUCIVE THROUGH THE FIRST 72 HOURS OF
THE FORECAST, ALLOWING FOR THE INTENSIFICATION. AFTER TAU 72,
COOLING SEA SURFACE TEMPERATURES AND INCREASING SHEAR WILL CAUSE
25W TO WEAKEN THROUGH THE REMAINDER OF THE FORECAST PERIOD. 

MODEL DISCUSSION: NUMERICAL MODEL TRACK GUIDANCE IS IN GOOD
AGREEMENT THROUGH TAU 72 WITH A 165 NM CROSS-TRACK SPREAD AT TAU
72. AFTERWARD, MODELS GREATLY DIVERGE AND BIFURCATE. ECMWF, NAVGEM,
AND GALWEM HAVE THE VORTEX MAKING A LOOP, FAILING TO RECURVE, AND
TRACKING OUT WESTWARD. AI MODELS AND GFS DEPICT THE MORE TEXTBOOK 
RECURVE SCENARIO. THE JTWC TRACK FORECAST IS MORE IN LINE WITH THE AI 
MODELS AND GFS AFTER TAU 72 WITH VERY LOW CONFIDENCE. INTENSITY 
GUIDANCE IS IN SLIGHTLY BETTER AGREEMENT WITH COAMPS-TC CLOSER TO 
HAFS-A REGARDING THE PEAK. HAFS-A IS AROUND 105 KTS WHILE COAMPS-TC IS 
AROUND 125 KTS. ALL MODELS AGREE ON WEAKENING AFTER TAU 72. THE JTWC 
INTENSITY FORECAST IS PLACED CLOSE TO THE MULTI-MODEL CONSENSUS WITH 
MEDIUM CONFIDENCE THROUGH TAU 72 AND LOW CONFIDENCE THEREAFTER.

FORECAST CONFIDENCE:
   TRACK 00-72 HR: HIGH
   TRACK 72-120 HR: LOW
   INTENSITY 00-72 HR: MEDIUM
   INTENSITY 72-120 HR: LOW//
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