WDPN31 PGTW 061500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 05W (HAGUPIT) WARNING NR 
004//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 7.1N 145.7E
   INITIAL INTENSITY: 35 KTS
   GEOGRAPHIC REFERENCE: 370 NM WEST OF CHUUK
   MOVEMENT PAST 6 HOURS: WEST-SOUTHWESTWARD AT 12 KTS
   SIGNIFICANT WAVE HEIGHT: 15 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TROPICAL
STORM (TS) 05W AS AN ELONGATED AND PARTIALLY EXPOSED LOW LEVEL
CIRCULATION CENTER (LLCC). THE 061119Z ASCAT PASS REVEALS 05W IS
EMBEDDED IN A REGION OF EXTENDED TROUGHING WITH THE HIGHEST WIND
SPEEDS CONFINED TO THE NORTHEASTERN QUADRANT. THE ASCAT DATA ALSO
INDICATES THAT THE PERSISTENT DEEP CONVECTION PRESENT IN ANIMATED
EIR IS CAUSED BY SURFACE CONVERGENCE, RATHER THAN A DEVELOPED
CIRCULATION UNDER THE CONVECTION. AS A RESULT OF THE DISORGANIZED
WIND FIELD PRESENT IN THE ASCAT, THE INITIAL POSITION IS PLACED WITH
LOW CONFIDENCE. THE INITIAL INTENSITY OF 35 KTS IS ASSESSED WITH
MEDIUM CONFIDENCE BASED ON THE ASCAT DATA REVEALING WIND SPEEDS
BETWEEN 25-30 KTS, WITH A FEW 35 KT WIND BARBS, SUPPORTED BY THE
AGENCY DVORAK FIXES AND CIMSS AUTOMATED INTENSITY ESTIMATES LISTED
BELOW. ENVIRONMENTAL ANALYSIS REVEALS A MARGINAL ENVIRONMENT
CHARACTERIZED BY MODERATE TO HIGH (15-20 KTS) MID-LEVEL VERTICAL
WIND SHEAR AND DRY AIR ENTRAINMENT, OFFSET BY MODERATE POLEWARD
OUTFLOW AND WARM (29-30 C) SEA SURFACE TEMPERATURES.

INITIAL WIND RADII BASIS: 061119Z ASCAT SCATTEROMETER DATA

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) CENTERED TO THE
NORTHEAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   RJTD: T2.0 - 30 KTS
   RCTP: T2.0 - 30 KTS
   KNES: T2.5 - 35 KTS

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY
UNFAVORABLE
   VWS: 15-20 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE POLEWARD
   OTHER FACTORS: DRY SURROUNDING ENVIRONMENT RESULTING IN DRY AIR
ENTRAINMENT FROM THE WEST

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

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THE SYSTEM CENTER HAS BEEN RELOCATED
APPROXIMATELY 30 NM TO THE SOUTHWEST OF THE ANTICIPATED SIX HOUR
FORECAST POSITION. AS A RESULT, THE CURRENT FORECAST TRACK LIES TO
THE SOUTH OF THE PREVIOUS FORECAST TRACK. THE EXTENDED FORECAST
TAUS DID NOT CHANGE SIGNIFICANTLY, HOWEVER, WITH THE PREVIOUSLY
FORECASTED TAU 120 ONLY 60NM NORTHWEST OF THE CURRENT TAU 120. THE
INTENSITY FORECAST IS CONSISTENT WITH THE PREVIOUS WARNING.

FORECAST DISCUSSION: TS 05W (HAGUPIT) IS ANTICIPATED TO BEGIN
TRACKING WESTWARD TO WEST-NORTHWESTWARD WITHIN THE NEXT 12 HOURS,
AS THE SHORTWAVE TROUGH TO THE NORTH WEAKENS AND REORIENTS THE
STEERING STR. AS A RESULT OF THE STR SHIFTING EASTWARD, 05W WILL
TRACK NORTHWESTWARD FROM TAU 12-120. REGARDING INTENSITY, 05W IS
FORECAST TO REMAIN AROUND 35 KTS THROUGH TAU 24, BEFORE
INTENSIFYING SLIGHTLY AND PEAKING AROUND 45KTS BETWEEN TAU 48-72.
THE STORM IS CONTENDING WITH A RELATIVELY DRY SURROUNDING
ENVIRONMENT, WITH THE MODERATE VERTICAL WIND SHEAR FORCING DRY AIR
INTO THE CORE, STIFLING DEVELOPMENT. HAGUPIT'S SAVING GRACE FOR
INTENSIFICATION IS EXPECTED TO BE A SLIGHTLY MORE FAVORABLE OUTFLOW
CHANNEL CREATED BY THE PASSING SHORTWAVE TROUGH BETWEEN TAU 48-72.
FOLLOWING TAU 72, HAGUPIT WILL BEGIN ITS TERMINAL WEAKENING CAUSED
BY THE INCREASING MID-LEVEL VERTICAL WIND SHEAR AND DRY AIR
ENTRAINMENT. DISSIPATION IS EXPECTED NO LATER THAN TAU 120. 

MODEL DISCUSSION: DETERMINISTIC MODEL TRACK GUIDANCE IS IN MODERATE
AGREEMENT, DISCOUNTING NAVGEM. THE EXPERIMENTAL AI MODELS ARE
TIGHTLY CLUSTERED SLIGHTLY SOUTH OF THE PHYSICS-BASED MULTI-MODEL
CONSENSUS. THE JTWC TRACK FORECAST IS PLACED BETWEEN THE
MULTI-MODEL CONSENSUS AND THE EXPERIMENTAL AI-MODELS WITH OVERALL
MEDIUM CONFIDENCE. RELIABLE INTENSITY MODELS REMAIN IN GOOD
AGREEMENT, WITH ALL RELIABLE MODELS INDICATING A PEAK INTENSITY
BETWEEN 40-45KTS AROUND TAU 60 AND DISSIPATION BY TAU 120. AS A
RESULT, THE JTWC INTENSITY FORECAST IS PLACED WITH OVERALL MEDIUM
CONFIDENCE. 

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