WDPN34 PGTW 110300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 27W (TWENTYSEVEN) 
WARNING NR 001//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 12.4N 139.2E
   INITIAL INTENSITY: 30 KTS
   GEOGRAPHIC REFERENCE: 321 NM WEST OF NAVSTA GUAM
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 16 KTS
   SIGNIFICANT WAVE HEIGHT: 15 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) AND TOTAL
PRECIPITABLE WATER LOOPS CONFIRM IMPROVING ORGANIZATION AND
DEEPENING CONVECTION AROUND TROPICAL DEPRESSION 27W. THE JTWC FIX
ESTABLISHES THE FIRST POSITION WHILE THE DVORAK VALUES OF JTWC T1.5
BALANCED WITH THE JMA T2.0 (35KTS) RESULT IN AN INITIAL INTENSITY
ASSESSMENT OF 30 KNOTS. THE SYSTEM DEVELOPED AT THE SOUTHEAST END
OF AN ACTIVE ZONE EXTENDING FROM THE PHILIPPINE SEA OFF THE
NORTHEAST COAST OF LUZON, WHERE TY 26W TORAJI IS NOW GOING ASHORE,
TO KOSRAE. THIS SYSTEM IS POINTED THE SAME WAY. ANIMATED WATER
VAPOR IMAGERY SHOWS IMPROVING EQUATORIAL OUTFLOW OVER THE SOUTHWEST
SECTOR AND GOOD POLEWARD OUTFLOW THROUGHOUT.  THE WATER VAPOR ALSO
REVEALS A GAPING DEARTH OF DEEP MOISTURE BETWEEN THE SYSTEM AND THE
140TH MERIDIAN BUT 27W LOOKS TO BE COCOONING ITSELF FROM THE OUTER
ENVIRONMENT. THERE IS LOW VERTICAL WIND SHEAR ALONG TRACK.  TD27W
EXISTS ALMOST DIRECTLY SOUTH OF A 593DM H500 HGT CENTER (THE BONIN
HIGH), WHICH WILL KEEP THE SYSTEM MOVING IN A WEST-NORTHWESTERLY
DIRECTION. DUE TO THE EARLY STAGE OF THE STORM NO AUTOMATED
ASSESSMENTS ARE AVAILABLE YET BUT THE DVORAK ESTIMATES ARE 
CONVINCING. 

INITIAL WIND RADII BASIS: NOT APPLICABLE (THERE ARE NO INITIAL WIND
RADII).

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T1.5 - 25 KTS
   RJTD: T2.0 - 30 KTS
   KNES: T1.5 - 25 KTS

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

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   INITIAL INTENSITY: MEDIUM
   INITIAL WIND RADII: NOT APPLICABLE

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THIS INITIAL PROGNOSTIC REASONING
MESSAGE ESTABLISHES THE FORECAST PHILOSOPHY.

FORECAST DISCUSSION: TROPICAL DEPRESSION 27W WILL BE DRIVEN ALONG A
WEST-NORTHWESTERLY TRACK TOWARDS THE NORTHEAST TIP OF LUZON BY THE
SUBTROPICAL RIDGE. THERE IS NOWHERE ELSE FOR IT TO GO. THE INITIAL
AIM POINT IS FOR THE NORTHEAST TIP OF LUZON. THE SYSTEM WILL
INTENSIFY STEADILY AT A ROUGHLY CLIMATOLOGICAL RATE. THE FORECAST
THROUGH THE PHILIPPINE SEA IS OF ABOVE-AVERAGE CONFIDENCE IN BOTH
TRACK AND INTENSITY BUT ONCE THE SYSTEM MOVES INTO THE
PHILIPPINES-LUZON STRAIT AREA THERE IS VERY POOR CONFIDENCE. LAND
INTERACTION OR LACK THEREOF, ALONG WITH THE EFFECTS OF MID-LATITUDE 
SYSTEMS TRACKING THROUGH SOUTHEASTERN CHINA AND AFFECT THE WESTERN 
FLANK OF THE RIDGE ARE TOO FAR OVER THE HORIZON TO SEE AT THIS POINT. 
BOTH DETERMINISTIC AND ENSEMBLE GUIDANCE IS BIFURCATED, WITH SOME 
SHOWING A TEXT-BOOK RECURVATURE AND EXTRA-TROPICAL TRANSITION 
SCENARIO WHILE OTHERS SHOW A STRONG DECOUPLING WITH A SLOW DEATH OVER 
THE NORTHERN SOUTH CHINA SEA. STAY TUNED, FOLKS. 

MODEL DISCUSSION: THE ECMWF ENSEMBLE MEAN LIKES THE RECURVATURE
SCENARIO WHILE THE GFS ENSEMBLE LIKES THE DECAPITATION AND FIZZLE
OUT ON A TRACK TOWARDS VIETNAM, JUST LIKE THE PATHETIC WRETCH
FORMERLY KNOWN AS TYPHOON 24W IS DOING TODAY.   

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