WDPN32 PGTW 240300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 05W (GAEMI) WARNING NR 018//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 23.5N 123.3E
   INITIAL INTENSITY: 120 KTS
   GEOGRAPHIC REFERENCE: 137 NM SOUTHEAST OF TAIPEI, TAIWAN
   MOVEMENT PAST 6 HOURS: NORTH-NORTHWESTWARD AT 07 KTS
   SIGNIFICANT WAVE HEIGHT: 41 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A DISTINCT
CLOUD-FILLED EYE WITH DEEP CONVECTION PLACED SOUTH AND SOUTHWEST OF
CENTER DUE TO MODERATE VERTICAL WIND SHEAR OF 10-15KTS FROM THE 
NORTH. TYPHOON 05W (GAEMI) COMPLETED THE EYEWALL REPLACEMENT CYCLE
(ERC) DURING THE LAST SIX HOURS AND NOW DISPLAYS A FULLY INTACT EYE
FEATURE ON RADAR IMAGERY. A LARGE REGION OF DEEP CONVECTIVE BANDING
STRETCHES FROM THE SOUTHEAST TO THE SOUTHWEST OF THE SOUTHERN
PORTION OF THE TYPHOON AND IS APPARENT ON A 2322Z F17 SSMIS 91GHZ
IMAGE. TROCHOIDAL MOTION IS EVIDENT BOTH ON ANIMATED MSI AND
RADAR AND IS INDICATIVE OF THE INTENSE NATURE OF THE SYSTEM. THE 
COOLER EYE TEMPERATURE INDICATED ON ANIMATED ENHANCED INFRARED 
IMAGERY (EIR) AND THE LARGER EYE DIAMETER, WHICH INCREASED FROM 5NM 
ON THE LAST CYCLE TO 17NM INDICATES THAT TY 05W HAS NOT INTENSIFIED 
SIGNIFICANTLY SINCE THE LAST WARNING. THE INITIAL POSITION IS PLACED 
WITH HIGH CONFIDENCE BASED ON THE AFOREMENTIONED ANIMATED MSI, EIR, 
AND RADAR IMAGERY. THE INITIAL INTENSITY OF 120 KTS IS ASSESSED WITH 
MEDIUM CONFIDENCE BASED ON THE AGENCY AND OBJECTIVE FIXES LISTED 
BELOW.

INITIAL WIND RADII BASIS: PERSISTENCE 

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T6.5 - 127 KTS
   RJTD: T5.5 - 102 KTS
   RCTP: T6.0 - 115 KTS
   DEMS: T6.5 - 127 KTS
   CIMSS SATCON: 106 KTS AT 2100Z
   CIMSS ADT: 109 KTS AT 0030Z

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

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: TY 05W IS FORECAST TO HAVE A TRACK MADE GOOD
NORTHWESTWARD THROUGH THE END OF THE FORECAST PERIOD, BUT WILL
LIKELY BE DEFLECTED NORTHWARD BY THE TOPOGRAPHY OF NORTHERN TAIWAN,
RESULTING IN A TRACK THAT MAY GO FARTHER NORTH BETWEEN TAU 12-24
THAT IS NOT CAPTURED IN THE TEMPORAL RESOLUTION OF THE WARNING
GRAPHIC. TROCHOIDAL MOTION MAY ALSO CAUSE VARIATION TO THE EXACT
LOCATION WHICH THE SYSTEM REACHES MAINLAND TAIWAN. INTENSIFICATION
WILL CONTINUE TO A PEAK OF 125KTS OVER THE NEXT 12 HOURS WHILE TY
05W WILL REMAIN IN A REGION OF FAVORABLE SEA SURFACE TEMPERATURES
OF 30-31C, HIGH OCEAN HEAT CONTENT, STRONG UPPER-LEVEL DIVERGENCE
AND MODERATE VERTICAL WIND SHEAR (10-15KTS). BEYOND TAU 12, TY 05W
WILL WEAKEN WHILE INTERACTING WITH THE MAINLAND OF TAIWAN AND HIGH
VERTICAL WIND SHEAR OF 20-25KTS. THE HIGH VERTICAL WIND SHEAR WILL
PERSIST AS THE SYSTEM COMES BACK OUT OVER WATER IN THE TAIWAN
STRAIT BY TAU 24. BETWEEN TAU 24-36, THE SYSTEM WILL MAKE LANDFALL
IN MAINLAND CHINA AND CONTINUE TO WEAKEN DUE TO TOPOGRAPHIC
INTERACTION BEFORE COMPLETELY DISSIPATING BY TAU 96. 

MODEL DISCUSSION: DETERMINISTIC MODEL GUIDANCE IS IN STRONG
AGREEMENT THAT THE SYSTEM WILL CONTINUE TO TRACK NORTHWEST THROUGH
TAU 96, HOWEVER MESOSCALE MODELS HAFS-A AND HWRF DO NOT RETURN THE
TRACK NORTHWESTWARD AFTER INTERACTING WITH MAINLAND TAIWAN AND
INSTEAD TAKE THE TRACK NEARLY DUE NORTH AFTER ROUNDING THE NORTHERN
COAST. THE CROSS-TRACK SPREAD OPENS TO 300NM BY TAU 96 DUE TO VARYING 
INTERPRETATIONS OF HOW STRONGLY LAND WILL INTERACT WITH THE SYSTEM, 
BUT ALL SLIGHTLY CURVE IN A NORTHWEST TO NORTH-NORTHWEST DIRECTION AT 
TAU 96 AND BEYOND. THE INTENSITY GUIDANCE IS ALSO IN STRONG AGREEMENT 
THAT THE SYSTEM WILL EITHER PEAK OR STALL WITHIN THE FIRST 12 HOURS 
OF THE FORECAST BEFORE GRADUALLY WEAKENING AS TY 05W BECOMES 
INUNDATED WITH VERTICAL WIND SHEAR AND INTERACTS WITH MAINLAND JAPAN 
AND TAIWAN. 

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