WDPN32 PGTW 110300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 25W (MAN-YI) WARNING NR 
009//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 15.1N 152.7E
   INITIAL INTENSITY: 35 KTS
   GEOGRAPHIC REFERENCE: 400 NM EAST OF SAIPAN
   MOVEMENT PAST 6 HOURS: WEST-SOUTHWESTWARD AT 10 KTS
   SIGNIFICANT WAVE HEIGHT: 15 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS THE MAIN
CONVECTIVE SHIELD SHEARING OFF TO THE SOUTH DURING THE PAST EIGHT
HOURS WITH A NEW NUGGET OF CONVECTION RE-ESTABLISHING ITSELF OVER
THE LLCC. THE BEST TRACK CONTINUES TO BE FIXED AT THE LEADING EDGE
OF THAT CONVECTION. WATER VAPOR IMAGERY ALSO REVEALS ANOTHER
FOREBODING SIGN--A GAPING DEARTH OF DEEP MOISTURE BETWEEN THE STORM 
AND THE
140TH MERIDIAN--BUT TOTAL PRECIPITABLE WATER LOOPS INDICATE THE
SYSTEM IS DOING A DECENT JOB COCOONING ITSELF FROM THE ENVIRONMENT.
THE SYSTEM IS TRACKING TOWARDS A REGION OF 12-18 KNOTS OF
NORTHEASTERLY VERTICAL WIND SHEAR. THE INTENSITY ASSESSMENT IS
BASED ON FINAL-T NUMBERS AND AUTOMATED TOOLS FROM CIMSS RATHER THAN
CURRENT INTENSITIES. BOTH RJTD AND PGTW HAVE FINAL TS AT T2.5 AND
BOTH ADT AND AIDT ARE ALSO AT 35KTS. DMINT IS ALSO AT 33KTS.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: A STABLE SUBTROPICAL RIDGE EXTENDING
WEST THROUGH EAST ALONG THE 19TH THROUGH 23RD LATITUDES. 


AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.0 - 45 KTS
   RJTD: T2.5 - 35 KTS
   RCTP: T3.0 - 45 KTS
   KNES: T3.0 - 45 KTS
   CIMSS ADT: 35 KTS AT 2000Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 15 KTS
   SST: 30-31 CELSIUS
   OUTFLOW: MODERATE POLEWARD AND EQUATORWARD

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

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THE DISSIPATION OVER WATER SCENARIO
IN THE FAR RANGE HAS BEEN REMOVED AND A 120 HOUR FORECAST TRACK
RESTORED. 

FORECAST DISCUSSION: THERE ARE TWO ADJUSTMENTS TO THE 25W FORECAST.
FIRST, THE TRACK HAS BEEN WALKING FURTHER SOUTH AND WHAT WAS
SUPPOSED TO BE A 6-12 HOUR JOG TO THE WEST-SOUTHWEST HAS NOW GONE
ON FOR FOUR CONSECUTIVE FIXES. THE RESULT IS RATHER THAN A TRACK
NORTH OF SAIPAN, TD 25W IS NOW EXPECTED TO SHOOT THE GAP BETWEEN
TINIAN AND ROTA. HOWEVER, THE EXPECTED INTENSITY DURING THAT PASSAGE 
REMAINS IN THE SMALL CRAFT TO LOW GALE FORCE RANGE. THE SECOND
ADJUSTMENT IS TO LET GO OF THE DISSIPATION OVER THE PHILIPPINE SEA
SCENARIO, WHICH IS EASY TO ACCEPT GIVEN THE FERTILE WATERS OF THAT
REGION. IT IS MORE PLAUSIBLE THAT THE SYSTEM WILL STRUGGLE ALONG
ITS WEST-SOUTHWESTWARD TRACK BUT REMAIN ALIVE LONG ENOUGH TO
REINVIGORATE ITSELF ONCE IT RESUMES POLEWARD MOVEMENT ON THE LAST
LEG TOWARDS THE LUZON-TAIWAN AREA. AS THE STORM CROSSES THE
MARIANAS AND MOVES INTO A REGION OF LIGHTER VERTICAL WINDSHEAR, IT
IS LIKELY TO QUICKLY RETURN ABOVE GALE FORCE SO LONG AS IT IS ABLE
TO CARRY DEEP MOISTURE WITH IT.  MID-LEVEL MOISTURE PROGS SUPPORT
THIS SCENARIO. 

MODEL DISCUSSION: TRACK GUIDANCE CLINGS STUBBORNLY TO A RESUMPTION
OF A DUE WESTERLY TRACK THROUGH THE MARIANAS BUT UNTIL THAT TURN
MANIFESTS THE JTWC FORECAST WILL STAY CLOSER TO THE ECMWF ENSEMBLE.
POLEWARD OUTLIERS NAVGEM AND COAMPS-TC HAVE BEEN PULLING THE
CONSENSUS NORTH.  THE INTENSITY FORECAST IS MORE DIFFICULT THAN THE
TRACK FORECAST, WITH A WIDE SPREAD BETWEEN THE VARIOUS AIDS. THE
USUALLY RELIABLE AND MORE ACCURATE HAFS-A CONTINUES TO SHOW SHARP
RE-DEVELOPMENT OVER THE PHILIPPINE SEA WHILE THE REST OF THE
GUIDANCE REMAINS SCATTERED. FNMOC OUTAGES CONTINUE TO DEPRIVE US OF
STATISTICAL DYNAMICAL AND SOME OF THE BEST COUPLED GUIDANCE. 

FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: MEDIUM
   TRACK 72-120 HR: LOW
   INTENSITY 0 - 72 HR: MEDIUM
   INTENSITY 72-120 HR: LOW//
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