WDPN31 PGTW 110300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 03W (NURI) WARNING 
NR 001//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 10.4N 136.8E
   INITIAL INTENSITY: 30 KTS
   GEOGRAPHIC REFERENCE: 94 NM NORTHWEST OF YAP
   MOVEMENT PAST 6 HOURS: SOUTHWESTWARD AT 10 KTS
   SIGNIFICANT WAVE HEIGHT: 14 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS AN
ELONGATED, BUT CONSOLIDATING, FULLY EXPOSED LOW-LEVEL CIRCULATION
CENTER (LLCC) OF TROPICAL DEPRESSION (TD) 03W (NURI). PERSISTENT
CONVECTION TO THE NORTHEAST HAS BEEN PRESENT OVER THE LAST 12
HOURS. MAXIMUM SURFACE WINDS OF 25-30 KTS WERE PREVIOUSLY ANALYZED 
UTILIZING A 101240Z METOP-C ASCAT PASS, HOWEVER, THE CIRCULATION 
REMAINED ILL-DEFINED AND HIGHLY ASYMMETRICAL AT THE TIME. THE INITIAL
POSITION FOR THIS WARNING IS PLACED WITH HIGH CONFIDENCE BASED ON
A CLEARLY IDENTIFIABLE, SLIGHTLY ELONGATED, BUT SIGNIFICANTLY BETTER
ORGANIZED LLCC OBSERVED IN THE VISIBLE SATELLITE IMAGERY LOOP. THE
INITIAL INTENSITY OF 30 KTS IS ASSESSED WITH MEDIUM CONFIDENCE
BASED ON THE AFOREMENTIONED, EARLIER ASCAT PASS, 26 KTS DPRINT
ESTIMATE AND AGENCY DVORAK FIXES LISTED BELOW. ENVIRONMENTAL
ANALYSIS REVEALS MARGINAL CONDITIONS FOR DEVELOPMENT CHARACTERIZED
BY WARM (28-29 C) SEA SURFACE TEMPERATURES (SST), MODERATE POLEWARD
OUTFLOW, OFFSET BY DRY AIR ENTRAINMENT ORIGINATING FROM AN
AIR MASS CENTERED TO THE NORTHWEST AND LOW TO MODERATE (15-20 KTS),  
BUT INCREASING VERTICAL WIND SHEAR (VWS).

INITIAL WIND RADII BASIS: NOT APPLICABLE (THERE ARE NO INITIAL WIND
RADII).

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) TO THE EAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.0 - 30 KTS
   RJTD: T2.5 - 35 KTS
   RCTP: T2.0 - 30 KTS
   KNES: T2.5 - 35 KTS
   CIMSS D-PRINT: 26 KTS AT 110000Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 15-20 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: MODERATE POLEWARD
   OTHER FACTORS: DRY AIR ENTRAINMENT FROM THE WEST AND SOUTHWEST

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   INITIAL INTENSITY: MEDIUM
   INITIAL WIND RADII: NOT APPLICABLE

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THIS INITIAL PROGNOSTIC REASONING
MESSAGE ESTABLISHES THE FORECAST PHILOSOPHY.

FORECAST DISCUSSION: TD NURI REMAINED QUASI-STATIONARY OVER THE
LAST FEW HOURS AND IS FORECAST TO SLOWLY BEGIN TURNING SOUTHEASTWARD 
AND EASTWARD WITHIN THE NEXT 6 TO 12 HOURS. AFTER THE INITIAL TURN, IT 
IS FORECAST TO ACCELERATE AND TRANSIT NORTHEASTWARD UNDER THE 
INFLUENCE OF A BROAD, DEEP-LAYER STR CENTERED TO THE EAST. IN TERMS OF 
INTENSITY, THE SYSTEM WILL REMAIN WITHIN A MARGINAL ENVIRONMENT OVER 
THE NEXT 24-36 HOURS, ALLOWING FOR SLIGHT INTENSIFICATION, 
PARTICULARLY IF THE VORTEX ALIGNS VERTICALLY AND MAINTAINS DEEP 
CONVECTIVE STRUCTURE. AROUND TAU 36, THE CONDITIONS WILL BEGIN TO 
RAPIDLY DETERIORATE, WITH VWS INCREASING TO 25-30 KTS AND DRY AIR 
INTRUSION OVERWHELMING THE VORTEX. AS THE SYSTEM MOVES FURTHER AWAY 
FROM THE SUBTROPICAL RIDGE AXIS BETWEEN TAUS 48 AND 72, TD 03W WILL 
BEGIN TO INTERACT WITH A LONG-WAVE, UPPER-LEVEL TROUGH, AND EVENTUALLY 
BECOME EMBEDDED WITHIN THE BAROCLINIC ZONE FLOW. GIVEN THE SHORT 
TIMELINE AND INCREASINGLY UNFAVORABLE CONDITIONS FOR DEVELOPMENT, THE 
VORTEX WILL LIKELY DISSIPATE BEFORE IT BECOMES A COLD-CORE, 
EXTRATROPICAL
CYCLONE.

MODEL DISCUSSION: NUMERICAL MODEL TRACK GUIDANCE IS IN FAIR AGREEMENT 
WITH THE MAJORITY OF THE UNCERTAINTY ASSOCIATED WITH THE INITIAL 12 
HOURS OF MOVEMENT, WITH SOME MODELS (JGSM, GFS ENSEMBLE, GALWEM) 
DEPICTING IMMEDIATE NORTHEASTWARD TRACK, WHILE OTHERS (NAVGEM, EMCWF
ENSEMBLE) DEPICT A SOUTH-SOUTHEASTWARD INITIAL TRACK, FOLLOWED BY A 
GRADUAL COUNTERCLOCKWISE TURN IN GUIDANCE DIRECTION. AFTER THAT, ALL 
MODELS PREDICT ACCELERATION AND TRACK ALONG THE NORTHWESTERN PERIPHERY 
OF THE SUBTROPICAL RIDGE WITH JGSM BEING THE ONLY OUTLIER TAKING THE 
TRACK 130-150 NM NORTHWEST OF THE MULTI-MODEL GUIDANCE ENVELOPE. AS 
SUCH, THE JTWC OFFICIAL TRACK FORECAST IS LAID WITH MEDIUM CONFIDENCE 
AND SLIGHTLY TO THE RIGHT OF THE MULTI-MODEL CONSENSUS TRACKER. IN 
REGARD TO INTENSITY, STATISTICAL-DYNAMICAL MODELS, AND HAFS DEPICT 
SLIGHT INTENSIFICATION, WHILE GFS SHOWS A STEADY WEAKENING TREND.
INTENSITY GUIDANCE SPREAD IS WITHIN 15 KTS, THEREFORE, THE OVERALL
CONFIDENCE IN JTWC FORECAST IS ASSESSED AS MEDIUM.

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