WDPN31 PGTW 231500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 08W (EIGHT) WARNING 
NR 003//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 16.9N 149.9E
   INITIAL INTENSITY: 30 KTS
   GEOGRAPHIC REFERENCE: 257 NM EAST-NORTHEAST OF SAIPAN
   MOVEMENT PAST 6 HOURS: WEST-SOUTHWESTWARD AT 10 KTS
   SIGNIFICANT WAVE HEIGHT: 12 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED PROXY-VIS SATELLITE IMAGERY SHOWS A DISORGANIZED BUT
CONSOLIDATING SYSTEM WITH THE MAIN CONVECTION, ALTHOUGH SHEARED
EASTWARD, ENCROACHING INTO BUT STILL PARTIALLY EXPOSING THE LOW
LEVEL CIRCULATION CENTER (LLCC). THE SATELLITE LOOP ALSO SHOWS THE
STEADY INFLUX OF COOL DRY AIR FROM THE NORTH AS EVIDENCED BY A
STREAM OF STRATOCUMULUS STREAKS WRAPPING INTO THE LLCC. THE INITIAL
POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE PARTIALLY EXPOSED 
LLCC. THE INITIAL INTENSITY IS ALSO HELD WITH HIGH CONFIDENCE BASED ON
THE DVORAK ESTIMATES FROM PGTW, KNES, AND ADT. ANALYSIS INDICATES A
MARGINALLY FAVORABLE ENVIRONMENT WITH STRONG POLEWARD OUTFLOW AND
VERY WARM SST OFFSET BY THE DRY AIR INTRUSION AND MODERATE VWS
ALOFT.

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

CURRENT STEERING MECHANISM: QUASI STATIONARY (QS) IN A COL BETWEEN
THE LOW REFLECTIONS OF THE SUBTROPICAL RIDGE (STR) TO THE NORTHWEST
AND THE NEAR EQUATORIAL RIDGE (NER) TO THE SOUTHEAST.


AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.0 - 30 KTS
   RJTD: T1.0 - 25 KTS
   KNES: T2.0 - 30 KTS
   CIMSS ADT: 33 KTS AT 231130Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 10-15 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG POLEWARD
   OTHER FACTORS: LOW LEVEL COOL DRY AIR INTRUSION FROM THE NORTH.

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TD 08W WILL REMAIN QS OVER THE NEXT 24-36HRS.
AFTERWARD, THE NER WILL BUILD AND BECOME THE DOMINANT STEERING
MECHANISM AND SLOWLY DRIVE THE CYCLONE NORTHWARD. AFTER TAU 72, A
SECONDARY DEEP-LAYERED STR TO THE NORTHEAST WILL ASSUME STEERING AND 
DRIVE THE CYCLONE NORTHWESTWARD TOWARD JAPAN. THE MARGINALLY FAVORABLE 
ENVIRONMENT WILL FUEL A GRADUAL INTENSIFICATION TO 45KTS DURING THE QS 
PHASE. AFTERWARD, INCREASING POLEWARD OUTFLOW AND DIMINISHING DRY AIR 
INTRUSION AT THE LOW LEVELS WILL PROMOTE FURTHER INTENSIFICATION TO 
65KTS BY TAU 120. WORTH MENTIONING AT THIS EARLY STAGE IS THAT TD 08W 
WILL TRACK ALONG THE EASTERN BOUNDARY OF A GYRE THE INCLUDES MULTIPLE 
VORTICES OVER A WIDE AREA BOUNDED BY JAPAN, TAIWAN, AND THE PHILIPPINE
ISLAND OF LUZON. THE WIND FIELD OF THIS SYSTEM IS FORECAST TO
BECOME VERY EXPANSIVE WITH SUBTROPICAL CHARACTERISTICS.

MODEL DISCUSSION: NUMERICAL MODELS ARE IN VERY LOOSE AGREEMENT BUT
WITH A VERY WIDE SPREAD. GFS IS ON THE EXTREME RIGHT MARGIN OF THE
ENVELOPE WITH A PROLONGED NORTHEASTWARD TRACK UP TO TAU 96 BEFORE
MERGING BACK INTO THE PACK. UKMET IS ON THE EXTREME LEFT MARGIN
WITH AN IMMEDIATE NORTHWESTWARD TRAJECTORY AFTER TAU 24. GIVEN
THESE, PLUS THE UNCERTAINTIES INHERENT WITH QS STORM MOTION, THERE
IS LOW CONFIDENCE IN THE WHOLE DURATION OF THE JTWC TRACK AND
INTENSITY FORECASTS. 

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