WDPN31 PGTW 061500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 03W (GUCHOL) WARNING NR 
003//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 14.4N 134.8E
   INITIAL INTENSITY: 35 KTS
   GEOGRAPHIC REFERENCE: 352 NM NORTH-NORTHWEST OF YAP
   MOVEMENT PAST 6 HOURS: NORTHWARD AT 06 KTS
   SIGNIFICANT WAVE HEIGHT: 16 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A WELL
DEFINED AND CONSOLIDATING CIRCULATION WITH TIGHTLY WRAPPING BANDS
OF CONVECTION IN ALL QUADRANTS. A PLETHORA OF DRY AIR TO THE NORTH
OF THE CIRCULATION IS ALLOWING FOR A PARTIALLY EXPOSED LLCC. A
RECENT 061143Z AMSU-B 89GHZ MICROWAVE IMAGE SHOWS FRAGMENTED
BANDING STRUCTURES AND MARGINAL CENTRAL CONVECTION. THE INITIAL
POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON EIR AND AMSU-B
IMAGERY. THE INITIAL INTENSITY OF 35 KTS IS ASSESSED WITH MEDIUM
CONFIDENCE BASED ON THE PREPONDERANCE OF EVIDENCE INCLUDING: CIMSS
ADT, CIMSS DEEP IR INTENSITY OF TC (D-PRINT) AND AGENCY DVORAK
INTENSITY ESTIMATES INDICATING SLIGHTLY HIGHER THAN 30KTS.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: NEAR EQUITORIAL RIDGE (NER) TO THE
SOUTH AND A SUBTROPICAL RIDGE (STR) TO THE EAST AND NORTH

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.0 - 30 KTS
   RJTD: T2.0 - 30 KTS
   KNES: T2.0 - 30 KTS
   CIMSS ADT: 32 KTS AT 061130Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 0-5 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE EQUATORWARD
   OTHER FACTORS: MODERATE OUTFLOW BOTH EQUATORWARD AND EASTWARD

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: OVER THE NEXT 12 HOURS, TS 03W (GUCHOL) IS
FORECAST TO BEGIN A GRADUAL TURN NORTH-NORTHWESTWARD UNDER THE
STEERING INFLUENCES OF THE NER AND STR TO THE SOUTH AND EAST
RESPECTIVELY. CURRENTLY IN A FAVORABLE ENVIRONMENT CHARACTERIZED BY
WARM SSTS, LOW VERTICAL WIND SHEAR (VWS) AND MODERATE OUTFLOW
ALOFT, 03W IS FORECAST TO INTENSIFY TO AROUND 55KTS BY TAU 24. AS
THE SYSTEM DEVELOPS, SO TOO DOES THE STEERING PATTERN. BY TAU 36,
NOW UNDER THE INFLUENCE OF THE DEEP LAYER MEAN FLOW PATTERN, 03W
WILL TRACK WEST-NORTHWESTWARD AND CONTINUE TO INTENSIFY. NEAR TAU
48, INCREASING VERTICAL WIND SHEAR AND FALLING SSTS WILL SERIOUSLY
HAMPER ADDITIONAL INTENSIFICATION. BY TAU 72, HAVING PROGRESSED TO
AROUND 80KTS, 03W WILL APPROACH THE AXIS OF THE STR AND STEADY UP
ON A GENERALLY NORTHWARD TRACK. BY TAU 120, NOW 85KTS, 03W WILL
BEGIN TO FEEL THE INFLUENCE OF A HIGH AMPLITUDE TROUGH THAT DIGS
DOWN FROM THE WEST, RESULTING IN INCREASED SPEEDS BEYOND THE
FORECAST PERIOD.

MODEL DISCUSSION: NUMERICAL MODELS ARE IN GOOD AGREEMENT THROUGH
TAU 48 WITH ALL MEMBERS FOLLOWING THE MULTI-MODEL CONSENSUS AND
JTWC FORECAST TRACK. AFTER TAU 48, MODEL OUTPUT DOES FAN OUT
SLIGHTLY AS VARIOUS MEMBERS DISAGREE ON THE EXACT TIMING AND EXTENT
OF THE NORTHWARD TURN. RELIABLE MODEL INTENSITY GUIDANCE IS IN GOOD
AGREEMENT WITH A BULK OF THE GUIDANCE AS WELL AS SEVERAL RAPID
INTENSIFICATION (RI) AIDS INTENSIFYING THE SYSTEM SHARPLY THROUGH
TAU 48 AND MORE LIMITED THEREAFTER. FOR THESE REASONS THE JTWC
TRACK AND INTENSITY FORECASTS ARE PLACED INITIALLY WITH HIGH
CONFIDENCE AND WITH MEDIUM CONFIDENCE THEREAFTER.

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