WDPN31 PGTW 071500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 03W (GUCHOL) WARNING NR 
007//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 15.3N 133.1E
   INITIAL INTENSITY: 55 KTS
   GEOGRAPHIC REFERENCE: 734 NM SOUTH-SOUTHEAST OF KADENA AB
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 08 KTS
   SIGNIFICANT WAVE HEIGHT: 24 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A
CONSOLIDATING SERIES OF DEEP CONVECTIVE BANDS TIGHTLY WRAPPING INTO
A WELL DEFINED TROPICAL CYCLONE. A RECENT 070935Z SSMIS 91GHZ
MICROWAVE IMAGE INDICATES A LARGE BUT NEARLY COMPLETE MICROWAVE EYE
FEATURE WITH DEEP CONVECTION GENERALLY LIMITED TO THE SOUTHERN
SEMICIRCLE. A 070856Z SMAP MICROWAVE RADIOMETRY PASS REVEALED A
ROBUST FIELD OF 48-49KT (10-MIN AVERAGE) WINDS OR 53-55KT (1-MIN
AVERAGE) WINDS TO THE EAST OF THE LLCC. THE INITIAL POSITION IS
PLACED WITH HIGH CONFIDENCE BASED ON EIR AND SSMIS IMAGERY. THE
INITIAL INTENSITY OF 55 KTS IS ASSESSED WITH MEDIUM CONFIDENCE
BASED ON SMAP SCALAR WIND DATA AS WELL AS CIMSS D-PRINT WHICH SHOWS
56-59KTS WHILE DVORAK INTENSITY ESTIMATES AND CIMSS ADT LAG
SLIGHTLY BEHIND AT 45-50KTS.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: NEAR-EQUATORIAL RIDGE (NER) TO THE
SOUTH AND A NARROW EXTENSION OF THE STR TO THE NORTH

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.0 - 45 KTS
   RJTD: T3.0 - 45 KTS
   KNES: T3.0 - 45 KTS
   CIMSS ADT: 49 KTS AT 071130Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 0-5 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: MODERATE EASTWARD
   OTHER FACTORS: DRY AIR MASS TO THE NORTH

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TS 03W (GUCHOL) IS FORECAST TO RAPIDLY
INTENSIFY WITHIN THE NEXT 36 HOURS. DURING THIS TIME, AS THE NARROW
EXTENSION OF THE STR TO NORTH IS BROKEN DOWN, 03W WILL CONTINUE TO
TRACK NORTHWESTWARD IN A FAVORABLE ENVIRONMENT. LOW VERTICAL WIND
SHEAR (VWS), WARM SSTS AND FAVORABLE UPPER LEVEL OUTFLOW PROVIDED
BY A TROPICAL UPPER TROPOSPHERIC TROUGH (TUTT CELL) IS FORECASTED
TO INTENSIFY THE SYSTEM TO AROUND 90KTS. PAST TAU 36, AFTER THE
SHORT WAVE TROUGH BREAKS DOWN THE AFOREMENTIONED BLOCKING RIDGE TO
THE NORTH AND COMBINED WITH A REORIENTATION OF THE RIDGING TO THE
SOUTH AND EAST, 03W WILL BEGIN TO RECURVE POLEWARD. DURING THIS
SAME TIME, COOLING SSTS, INCREASING VWS AND DRY AIR ENTRAINMENT
WILL GRADUALLY WEAKEN THE SYSTEM AS IT IS PROPELLED NORTHEASTWARD.
BY TAU 120, NOW NORTH OF THE 28TH PARALLEL AND HAVING WEAKENED TO
70KTS, 03W WILL CONTINUE PICKING UP SPEED AND WEAKENING AS IT
FURTHER INTERACTS WITH AND EVENTUALLY INTEGRATES INTO THE PASSING
TROUGH.

MODEL DISCUSSION: NUMERICAL MODELS ARE IN GOOD AGREEMENT WITH A
TIGHT SPREAD IN MODEL OUTPUT THROUGH TAU 72, AFTER WHICH SLIGHT
CROSS-TRACK DEVIATIONS EMERGE THROUGH TAU 120. FOR THIS REASON THE
JTWC TRACK FORECAST IS PLACED INITIALLY WITH HIGH CONFIDENCE AND
WITH MEDIUM CONFIDENCE THEREAFTER. RELIABLE MODEL INTENSITY
GUIDANCE IS IN GOOD AGREEMENT WITH ALL MEMBERS AS WELL AS SEVERAL
RI AIDS SHOWING A SHARP INCREASE THROUGH TAU 36. AFTER TAU 36,
THERE IS A 15-20KT SPREAD IN MODEL OUTPUT THROUGH THE FORECAST
PERIOD. FOR THIS REASON THE JTWC INTENSITY FORECAST IS PLACED CLOSE
TO THE MULTI-MODEL CONSENSUS WITH OVERALL MEDIUM CONFIDENCE.

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