WDPN31 PGTW 072100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 05W (HAGUPIT) WARNING NR 
009//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 8.1N 141.2E
   INITIAL INTENSITY: 35 KTS
   GEOGRAPHIC REFERENCE: 202 NM EAST-SOUTHEAST OF YAP
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 08 KTS
   SIGNIFICANT WAVE HEIGHT: 15 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
TROPICAL STORM (TS) 05W (HAGUPIT) REMAINS A MOSTLY OBSCURED
LOW-LEVEL CIRCULATION CENTER (LLCC) WITH DEEP CONVECTIVE ACTIVITY
SHEARED EASTWARD ASIDE FROM AN IMPROVED BAND ON THE SOUTHERN HALF OF 
THE CIRCULATION
AS DEPICTED BY ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY.
CLOUD TOP TEMPERATURES HAVE NOT CHANGED SIGNIFICANTLY OVER THE PAST
SIX HOURS. ENVIRONMENTAL CONDITIONS REMAIN MODERATELY FAVORABLE FOR
CONTINUED DEVELOPMENT WITH WARM SEA SURFACE TEMPERATURES (29 C TO
30 C), AND MODERATE POLEWARD AND EQUATORWARD OUTFLOW BALANCED BY
DRY AIR ENTRAINMENT AND MODERATE (15-20 KTS) WEST-NORTHWESTERLY
MID-TROPOSPHERIC SHEAR. THE INITIAL POSITION IS PLACED WITH HIGH
CONFIDENCE BASED ON AN EARLIER 071611Z AMSR2 MICROWAVE IMAGE OF THE
LLCC. THE INITIAL INTENSITY OF 35 KTS IS ASSESSED WITH MEDIUM
CONFIDENCE BASED ON THE AGENCY DVORAK FIXES AND CIMSS INTENSITY
ESTIMATES LISTED BELOW.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: SOUTHWESTERN PERIPHERY OF A DEEP-LAYER
SUBTROPICAL RIDGE POSITIONED TO THE NORTHEAST.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35  KTS
   RJTD: T2.5 - 35 KTS
   RCTP: T2.5 - 35 KTS

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 10-15 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE POLEWARD AND EQUATORWARD
   OTHER FACTORS: DRY MID-LEVEL AIR ALONG THE WESTERN FLANK AND
ELEVATED MID-LEVEL WESTERLY SHEAR.

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   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: TS HAGUPIT WILL CONTINUE TRACKING
WEST-NORTHWESTWARD UNDER THE INFLUENCE OF THE SUBTROPICAL RIDGE
POSITIONED TO THE NORTHEAST STRENGTHENING TO A 40 KT INTENSITY BY
TAU 12. THE SYSTEM WILL BARELY BE ABLE TO HOLD THIS INTENSITY AS IT
CONTINUES TO BATTLE WEST NORTHWESTERLY MID-TROPOSPHERIC SHEAR AND
DRY AIR ENTRAINMENT. THE FORECASTED TRACK WILL FORCE TS HAGUPIT
THROUGH PROLONGED UNFAVORABLE CONDITIONS INITIATING A TERMINAL
WEAKENING PHASE BY TAU 72 AND CAUSING THE SYSTEM TO DISSIPATE OVER
WATER BY TAU 120. 

MODEL DISCUSSION: CROSS TRACK SPREAD AMONGST THE MULTI MODEL
CONSENSUS IS SPREAD UP TO 100 NM BU TAU 48 INCREASING TO GREATER
THAN 200 NM BY TAU 96. NAVGEM AND GFS SHIFT NORTHWARD AHEAD OF ECMW 
AND
GALWEM WITH THE CONSENSUS AND EXPERIMENTAL AI SOLUTIONS FALLING IN
THE MIDDLE. THE JTWC FORECASTED TRACK LIES CLOSE TO THE MULTI MODEL
CONSENSUS WITH HIGH CONFIDENCE IN THE FIRST 48 HOURS AND MEDIUM
CONFIDENCE THEREAFTER. INTENSITY GUIDANCE IS IN GOOD AGREEMENT ON A
SLOW STRENGTHENING TO 40 KTS AND BARELY MAINTAINING SAID INTENSITY
BEFORE THE TERMINAL WEAKENING TREND AND DISSIPATION BY TAU 120. THE
JTWC FORECASTED INTENSITY REFLECTS CLOSELY THE MULTI MODEL
CONSENSUS WITH MEDIUM CONFIDENCE THROUGHOUT THE FORECAST PERIOD. 

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