WDPN32 PGTW 130900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 05E (DORA) WARNING NR 
052//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 18.3N 174.2E
   INITIAL INTENSITY: 55 KTS
   GEOGRAPHIC REFERENCE: 937 NM WEST OF JOHNSTON ISLAND
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 10 KTS
   SIGNIFICANT WAVE HEIGHT: 23 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A PARTIALLY
EXPOSED LOW LEVEL CIRCULATION CENTER (LLCC) THAT IS BECOMING MORE
EXPOSED BY THE MINUTE DUE TO THE PERSISTENT SOUTHWESTERLY SHEAR. A
130605Z SSMIS 91GHZ MICROWAVE IMAGE REVEALS A SMALL NAKED
CIRCULATION WITH A SMALL BLOOM OF CONVECTION EVIDENT TO THE
NORTHEAST OF THE LLCC. THE INITIAL POSITION IS PLACED WITH HIGH
CONFIDENCE BASED ON MSI AND SSMIS IMAGERY. THE INITIAL INTENSITY OF
55 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON PGTW AND KNES
DVORAK INTENSITY ESTIMATES TOGETHER WITH CIMSS AIDT INDICATING
55KTS, WHILE CIMSS ADT AND D-PRINT INDICATE SLIGHTLY HIGHER AT 63
KTS AND 67KTS RESPECTIVELY.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE TO THE NORTHEAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.0 - 65 KTS
   RJTD: T4.5 - 77 KTS
   KNES: T3.5 - 55 KTS
   CIMSS ADT: 67 KTS AT 130530Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY
UNFAVORABLE
   VWS: 15-20 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: MODERATE POLEWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   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: TROPICAL STORM DORA (05E) IS FORECAST TO
CONTINUE WEST-NORTHWESTWARD OVER THE NEXT 24 HOURS. DURING THIS
TIME, PERSISTENT SOUTHWESTERLY SHEAR WILL CONTINUE TO EAT AWAY AT
THE SYSTEM, RESULTING IN GRADUAL WEAKENING. AS THE SYSTEM CROSSES
THE 20TH PARALLEL, 05E WILL BE FORCED BETWEEN THE CURRENT STR AND A
NEW RIDGE THAT BUILDS TO THE NORTHWEST, THIS COMBINED STEERING
EFFECT WILL FORCE THE SYSTEM GENERALLY POLEWARD. THE INTENSITY OF
THE SYSTEM AFTER TAU 36 IS ENTIRELY DEPENDENT ON ITS TRACK. IF THE
SYSTEM IS ABLE TO WITHSTAND THE CURRENT VERTICAL WIND SHEAR AND
ENTER THE NORTHWARD TURN WITH A MAJORITY OF ITS STRENGTH, 05E WILL
TREND ON A MORE EASTWARD COURSE AS SEEN IN GFS AND NVGM. THIS
INSIDE TRACK WOULD BRING DORA INTO A REGION OF LOWER VERTICAL WIND
SHEAR AND THE UP-SHEAR ENVIRONMENT WOULD MOISTEN, FACILITATING A
PERIOD OF REINTENSIFICATION. ON THE OTHER HAND, THERE REMAINS A
CHANCE THAT DORA DISSIPATES BEFORE THIS OPPORTUNITY TO REINTENSIFY,
AS SHOWN BY THE ECMWF AND HWRF. THE JTWC OUTLOOK CONTINUES TO LEAN
TOWARDS A MORE RIGHT OF TRACK APPROACH WITH A MARGINAL AMOUNT OF
REINTENSIFICATION. AS THE SYSTEM PROGRESSES INTO THE HIGHER
LATITUDES, IT WILL BEGIN TO INTERACT WITH STRONG BAROCLINIC FORCES
THAT WILL INITIATE EXTRATROPICAL TRANSITION BY TAU 120.

MODEL DISCUSSION: NUMERICAL MODELS ARE IN GOOD AGREEMENT THROUGH
TAU 24 WITH MINIMAL CROSS TRACK SPREADING. AS THE TIMING AND EXTENT
OF THE NORTHWARD TURN VARIES AMONGST THE MEMBERS, THE CONSENSUS
BEYOND TAU 24 IS NOT AS TIGHT AND THEREFORE OF LOWER CONFIDENCE. FOR
THIS REASON THE JTWC TRACK FORECAST IS PLACED INITIALLY WITH MEDIUM
CONFIDENCE AND WITH LOW CONFIDENCE THEREAFTER. RELIABLE MODEL
INTENSITY GUIDANCE IS IN FAIR AGREEMENT WITH ALL MEMBERS GENERALLY
FOLLOWING THE MULTI-MODEL CONSENSUS THROUGH THE FORECAST PERIOD. AS
MENTIONED ABOVE, THERE IS A STRONG AND DIRECT CORRELATION BETWEEN
TRACK AND INTENSITY BEYOND TAU 36. THE JTWC FORECAST INTENSITY IS
THEREFORE PLACED WITH THE SAME CONFIDENCE AS THE TRACK FORECAST.

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