WDPN31 PGTW 062100

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//

SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 05W (HAGUPIT) WARNING NR

005//

RMKS/

1. FOR METEOROLOGISTS.

2. 6 HOUR SUMMARY AND ANALYSIS.



SUMMARY:

   INITIAL POSITION: 7.3N 144.7E

   INITIAL INTENSITY: 35 KTS

   GEOGRAPHIC REFERENCE: 18 NM EAST OF IFALIK

   MOVEMENT PAST 6 HOURS: WESTWARD AT 10 KTS

   SIGNIFICANT WAVE HEIGHT: 15 FEET



SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:

TROPICAL STORM (TS) 05W (HAGUPIT) HAS CONTINUED TO TRACK WESTWARD

WITH SOME RECONSOLIDATION EVIDENT AS THE ENVIRONMENTAL SHEAR HAS

RELAXED. PERSISTENT DEEP CONVECTION REMAINS EAST OF THE LOW-LEVEL

CIRCULATION CENTER (LLCC) AND IS BUILDING WITH COOLING CLOUD TOP

TEMPERATURES AS DEPICTED BY ANIMATED ENHANCED INFRARED (EIR)

SATELLITE IMAGERY. ENVIRONMENTAL CONDITIONS ARE NOW MARGINALLY

FAVORABLE FOR CONTINUED DEVELOPMENT WITH DECREASED VERTICAL WIND

SHEAR (05-10 KTS), WARM SEA SURFACE TEMPERATURES (29 C TO 30 C),

AND MODERATE POLEWARD OUTFLOW BALANCED BY SIGNIFICANT DRY AIR TO

THE WEST. THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE

BASED ON AN EARLIER 061430Z OSCAT SCATTEROMETER PASS. THE INITIAL

INTENSITY OF 35 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE

AFOREMENTIONED OSCAT PASS DEPICTING HIGHEST WIND SPEEDS IN THE

NORTHERN HALF OF THE CIRCULATION AS WELL AS THE SUBJECTIVE AND

OBJECTIVE ESTIMATES LISTED BELOW.



INITIAL WIND RADII BASIS: 061430Z OSCAT 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 FAVORABLE

   VWS: 5-10 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: MEDIUM

   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 IS FORECASTED TO INTENSIFY SLOWLY

OVER THE NEXT 24 HOURS AS IT CONTINUES WEST NORTHWESTWARD UNDER THE

INFLUENCE OF THE SUBTROPICAL RIDGE (STR) CENTERED TO THE NORTHEAST.

AFTER TAU 24 AN EASTWARD SHIFT OF THE STR WILL ALLOW THE UPPER

LEVEL OUTFLOW OF THE SYSTEM TO IMPROVE. THE IMPROVED OUTFLOW

COMBINED WITH A FORECASTED DECREASE IN VERTICAL WIND SHEAR BETWEEN

TAU 24 AND TAU 48 WILL CREATE A MORE FAVORABLE ENVIRONMENT AND

ALLOW THE SYSTEM TO REACH A MAXIMUM INTENSITY OF 50 KTS BY TAU 48.

THE FORECASTED PERIOD OF MORE FAVORABLE ENVIRONMENTAL CONDITIONS

REMAINS HIGHLY

DEPENDENT ON THE STRENGTH OF THE STR AND THE ABILITY OF TS HAGUPIT

TO RESIST DRY AIR ENTRAINMENT UNTIL THAT TIME. AFTERWARDS WIND

SHEAR IS EXPECTED TO INCREASE YET AGAIN WITH INCREASING DRY AIR

ENTRAINMENT FROM THE WEST WHICH WILL INITIATE A TERMINAL WEAKENING

PHASE

AS THE CIRCULATION CONTINUES INTO THE WESTERN PHILIPPINE SEA.



MODEL DISCUSSION: CROSS TRACK SPREAD AMONGST THE MULTI MODEL

CONSENSUS IS UP TO 125 NM BY TAU 48 WITH NAVGEM CONTINUING TO BE

THE OUTLIER WITH A MORE NORTHWESTERN TRACK AND THEN HOOK TO THE

EAST. THE REMAINDER OF THE GUIDANCE REMAINS ON TRACK TOWARD THE

EASTERN SIDE OF THE PHILIPPINES. THE JTWC FORECASTED TRACK IS

PLACED JUST SOUTH OF THE MULTI MODEL CONSENSUS ACCOUNTING FOR SOME

OF THE EXPERIMENTAL AI SOLUTIONS WITH HIGH CONFIDENCE IN THE 0-72

HOUR RANGE AND MEDIUM CONFIDENCE AFTERWARDS. INTENSITY GUIDANCE IN

GOOD AGREEMENT ON A SLOW INTENSIFICATION TREND IN THE 24-48 HOUR

TIME PERIOD. AFTERWARDS THE GUIDANCE IS MORE UNCERTAIN WITH GFS AND

HAFS-A DEPICTING A QUICK WEAKENING TREND WHILE COAMPS-TC AND THE

STATISTICAL DYNAMICAL SOLUTIONS HOLD INTENSITIES IN THE 45-50 KT

RANGE LONGER. THE JTWC FORECASTED INTENSITY REFLECTS CLOSELY THE

MULTI MODEL CONSENSUS VALUES WITH MEDIUM CONFIDENCE.



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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