WDPN32 PGTW 221500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 05W (GAEMI) WARNING NR 
012//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 18.4N 125.4E
   INITIAL INTENSITY: 60 KTS
   GEOGRAPHIC REFERENCE: 504 NM SOUTH-SOUTHWEST OF KADENA AB
   MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 03 KTS
   SIGNIFICANT WAVE HEIGHT: 24 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS
TROPICAL STORM (TS) 05W (GAEMI) AS HAVING PERSISTENT BUILDING 
CONVECTION OVER THE CENTER OF THE OBSCURED LOW-LEVEL CIRCULATION 
CENTER (LLCC). BANDING FEATURES CAN BE SEEN ALONG THE SOUTHERN AND 
WESTERN SECTORS, WRAPPING INTO THE CENTER. THE NORTHERN PERIPHERY OF 
THE SYSTEM SEEMS TO STILL FEEL THE EFFECTS OF THE PRESENCE OF A 
TONGUE OF DRY AIR THAT IS PLACED JUST NORTH OF THE LLCC, SLIGHTLY 
HINDERING CONVECTIVE DEVELOPMENT AT THE MOMENT. ENVIRONMENTAL 
ANALYSIS INDICATES THAT 05W IS IN A FAVORABLE ENVIRONMENT FOR 
INTENSIFICATION CHARACTERIZED BY MODERATE EQUATORWARD OUTFLOW ALOFT, 
LOW (10-15 KTS) VERTICAL WIND SHEAR, AND WARM (30-31 C) SEA SURFACE 
TEMPERATURES. THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE 
BASED ON EXTRAPOLATION FROM A 220952Z RCM-1 SAR WIND SPEED IMAGE. THE 
INITIAL INTENSITY OF 60 KTS IS ASSESSED WITH HIGH CONFIDENCE BASED ON 
THE SAR IMAGE ALONG WITH THE SUBJECTIVE AND OBJECTIVE INTENSITY 
ESTIMATES LISTED BELOW.

INITIAL WIND RADII BASIS: SAR DATA 

CURRENT STEERING MECHANISM: WESTERN PERIPHERY OF A DEEP-LAYER
SUBTROPICAL RIDGE (STR) TO THE EAST.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T4.0 - 65 KTS
   RJTD: T5.0 - 90 KTS
   RCTP: T4.0 - 65 KTS
   KNES: T3.5 - 55 KTS
   CIMSS SATCON: 69 KTS AT 221200Z
   CIMSS ADT: 61 KTS AT 221200Z
   CIMSS AIDT: 65 KTS AT 221200Z
   CIMSS DPRINT: 60 KTS AT 221200Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 10-15 KTS
   SST: 30-31 CELSIUS
   OUTFLOW: MODERATE EQUATORWARD

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TS O5W IS FORECAST TO CONTINUE TRACKING
NORTH-NORTHWESTWARD ALONG THE WESTERN PERIPHERY OF A NORTH-SOUTH
ORIENTED STR PLACED TO ITS EAST THROUGH TAU 36. AFTER TAU 36,
RIDGING EXTENDING ACROSS EASTERN CHINA WILL TAKE OVER AS THE
STEERING MECHANISM AND DRIVE 05W WESTWARD THROUGH TAU 96. THE
SYSTEM IS FORECAST TO MAKE LANDFALL ALONG THE EASTERN COAST OF
CHINA, NORTHWEST OF TAIWAN, NEAR TAU 72. AFTER MAKING LANDFALL, 05W
IS EXPECTED TO RAPIDLY WEAKEN AND THE LOW-LEVEL STEERING PATTERN
WILL PUSH THE SYSTEM POLEWARD AS IT DISSIPATES. REGARDING THE
INTENSITY FORECAST, 05W IS FORECAST TO CONTINUE TO INTENSIFY
THROUGH TAU 48 AS VERTICAL WIND SHEAR IS ANTICIPATED TO CONTINUE
DROPPING. HIGH SEA SURFACE TEMPERATURES AND OHC ARE GOING TO BE
LARGE FACTORS IN THE INTENSIFICATION OF 05W. THE PEAK INTENSITY OF
90 KTS IS FORECAST TO OCCUR AROUND TAU 36, JUST SOUTH OF
ISHIGAKIJIMA, BEFORE THE WESTWARD TURN IS INITIATED. AFTER TAU 48,
VERTICAL WIND SHEAR WILL RISE TO ABOVE 25 KTS AND SEA SURFACE
TEMPERATURES WILL DROP, WHICH WILL BEGIN THE WEAKENING TREND OF
05W. HOWEVER, AT LANDFALL, 05W IS FORECAST TO STILL BE VERY CLOSE
TO TYPHOON STRENGTH. AFTER LANDFALL, THE SYSTEM WILL DETERIORATE IN
RESPONSE TO TERRAIN INTERACTION AND WILL DISSIPATE NEAR THE END OF
THE FORECAST PERIOD. 

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE REMAINS IN GOOD
AGREEMENT WITH A 200 NM CROSS-TRACK SPREAD AT TAU 72, AROUND THE
TIME OF LANDFALL. NAVGEM MAKES UP THE SOUTHERNMOST MEMBER, TRACKING
THE SYSTEM THROUGH CENTRAL TAIWAN. ECMWF NOW MAKES UP THE
NORTHERNMOST MEMBER, TRACKING THE SYSTEM AROUND 50 NM NORTH OF THE
COAST OF TAIWAN. THE JTWC TRACK FORECAST IS PLACED WITH MEDIUM
CONFIDENCE JUST NORTH OF CONSENSUS, HUGGING THE NORTHERN COAST OF
TAIWAN AND PASSING DIRECTLY OVER TAIPEI AT AROUND TAU 60. THE
INTENSITY GUIDANCE IS IN RELATIVELY GOOD AGREEMENT WITH THE EXCEPTION 
OF RAPID INTENSIFICATION AIDS APPEARING. THE PRESENCE OF DRY AIR AND 
THE NORTHERLY VERTICAL WIND SHEAR WILL HINDER THE CHANCES FOR RI 
HAPPENING, AT LEAST IN THE SHORT TERM, BUT CAN'T BE RULED OUT 
COMPLETELY. GUIDANCE OTHERWISE AGREES ON A PEAK INTENSITY OF AROUND 
75 TO 90 KTS AT TAU 36-48 BEFORE WEAKENING RATHER QUICKLY. THE JTWC 
INTENSITY FORECAST IS PLACED WITH MEDIUM CONFIDENCE, ALONG THE HIGHER 
END OF GUIDANCE WITH A PEAK INTENSITY OF 90 KTS. 

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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