WDPN32 PGTW 050900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 05W (DANAS) WARNING NR 
006//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 20.5N 117.9E
   INITIAL INTENSITY: 55 KTS
   GEOGRAPHIC REFERENCE: 233 NM EAST-SOUTHEAST OF HONG KONG
   MOVEMENT PAST 6 HOURS: NORTHEASTWARD AT 03 KTS
   SIGNIFICANT WAVE HEIGHT: 17 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS DEEP
CONVECTIVE BANDING EXTENDING AS FAR AS 160-170 NM AWAY FROM A FULLY
OBSCURED LOW-LEVEL CIRCULATION CENTER (LLCC) OF TROPICAL STORM (TS)
05W (DANAS). THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE
BASED ON A WELL DEFINED CENTER PRESENT IN A 050548Z AMSR2 MICROWAVE
IMAGE. THE INITIAL INTENSITY OF 55 KTS IS ASSESSED WITH HIGH
CONFIDENCE BASED ON THE 05-0547Z AMSR2 7KM WIND SPEED PRODUCT
SHOWING A BAND OF 59-61 KTS DIRECTLY TO THE EAST OF THE LLCC AND
UNDERNEATH THE INTENSE CONVECTION. ADDITIONALLY, ANOTHER PATCH OF
SIMILAR WIND SPEED CAN BE IDENTIFIED APPROXIMATELY 100 NM TO THE
SOUTH. ENVIRONMENT IS HIGHLY CONDUCIVE TO FURTHER INTENSIFICATION,
AS WITNESSED BY STRONG RADIAL OUTFLOW ALOFT, LOW (10-15 KTS) VERTICAL 
WIND SHEAR AND VERY WARM (29-30 C) SEA SURFACE TEMPERATURES (SST).

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: COMPETING STEERING ENVIRONMENT WITH A
SUBTROPICAL RIDGE (STR) POSITIONED TO THE NORTH AND A
NEAR-EQUATORIAL RIDGE (NER) BUILDING TO THE SOUTHEAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.5 - 55 KTS
   RJTD: T2.5 - 35 KTS
   RCTP: T3.5 - 55 KTS
   KNES: T3.5 - 55 KTS
   DEMS: T3.5 - 55 KTS
   CIMSS SATCON: 53 KTS AT 050600Z
   CIMSS ADT: 53 KTS AT 050530Z
   CIMSS AIDT: 43 KTS AT 050600Z
   CIMSS D-MINT: 46 KTS AT 050549Z
   CIMSS D-PRINT: 42 KTS AT 050600Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE
   VWS: 10-15 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG RADIAL

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   INITIAL INTENSITY: HIGH
   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 05W IS FORECAST TO TRACK NORTHEASTWARD OVER
THE NEXT 48 HOURS. COMPETING STEERING ENVIRONMENT IS CAUSING THE
TRANSLATION SPEED TO OSCILLATE AROUND 3 KTS, WHILE THE SYSTEM
APPROACHES THE TAIWAN STRAIT. WITHIN THE NEXT 12-24 HOURS THE NER
TO THE EAST WILL BUILD AND AID IN DEFINING THE TRACK OF TS DANAS.
AROUND TAU 72 HOWEVER, NER WILL WEAKEN AND TRANSIT FURTHER SOUTH,
WHILE THE STR TO THE NORTH BUILDS AND EXTENDS EAST-SOUTHEAST,
RESULTING IN TS 05W SHARPLY TURNING TOWARDS MAINLAND CHINA. IN
TERMS OF INTENSITY, THE SYSTEM WILL LIKELY RAPIDLY INTENSIFY WITHIN
THE NEXT 24-48 HOURS, AS INDICATED BY MULTIPLE MODEL CONSENSUS
MEMBERS, INCLUDING SPECIFIC RAPID INTENSIFICATION (RI) AIDS (FRIA,
RIDE, RIPA, DTOP AND RICN), AS LONG AS THE VORTEX REMAINS OVER THE
WARM STRAIT WATERS. AROUND TAU 48, ONCE TS 05W MAKES A WESTWARD
TURN AND BEGINS TO INTERACT WITH THE TERRAIN AND EVENTUALLY MAKES
LANDFALL, THE FORECAST CALLS FOR RAPID WEAKENING. FULL DISSIPATION
OVER LAND IS FORECAST BY TAU 96.

MODEL DISCUSSION: NUMERICAL MODEL TRACK GUIDANCE IS IN FAIR
AGREEMENT WITH 55 NM CROSS-TRACK SPREAD AT TAU 36, WHILE THE SYSTEM
IS TRANSITING OVER THE TAIWAN STRAIT, EXPANDING TO 110 NM, JUST
NORTH OF THE STRAIT. ONE IMMEDIATE OUTLIER IS UKMET (EGRI) TRACKER
INDICATING LANDFALL OVER SOUTHERN TAIWAN AROUND TAU 36. BEYOND TAU
48, THE UNCERTAINTY INCREASES THROUGHOUT THE MODEL GUIDANCE,
THEREFORE THE LANDFALL POSITION IS ASSESSED WITH LOW CONFIDENCE.
INTENSITY GUIDANCE IS IN FAIR AGREEMENT THROUGHOUT THE FORECAST AS
WELL, AS WITNESSED BY STRONG AGREEMENT IN REGARD TO THE TIMELINE OF
INTENSIFICATION AND WEAKENING, OFFSET BY SOME UNCERTAINTY
ASSOCIATED WITH THE PEAK INTENSITY SPREAD, WHICH IS CURRENTLY
ASSESSED AT 40 KTS, EXCLUDING THE RI AIDS. THE TIMELINE OF
DISSIPATION IS IN GOOD AGREEMENT AMONG THE CONSENSUS MEMBERS
INDICATING INTENSITY BELOW WARNING CRITERIA AT OR BEFORE TAU 96,
FOR ALL AVAILABLE GUIDANCE. OVERALL GOOD MODEL GUIDANCE IS OFFSET
BY TRACK UNCERTAINTY AND ITS IMPACT ON INTENSIFICATION RATE IN
RELATION TO ANY POTENTIAL LAND INTERACTION, WHILE THE SYSTEM IS
WITHIN OR NEAR THE TAIWAN STRAIT. THEREFORE OVERALL JTWC INTENSITY
FORECAST IS ASSESSED WITH MEDIUM CONFIDENCE.

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