WDPN31 PGTW 250300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 22W (TRAMI) WARNING NR 
019//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 16.9N 118.8E
   INITIAL INTENSITY: 50 KTS
   GEOGRAPHIC REFERENCE: 188 NM NORTHWEST OF MANILA, PHILIPPINES
   MOVEMENT PAST 6 HOURS: WESTWARD AT 05 KTS
   SIGNIFICANT WAVE HEIGHT: 19 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A
CONSOLIDATING CENTRAL DENSE OVERCAST (CDO) THAT IS FULLY OBSCURING
THE LLCC BENEATH. A 242235Z SSMIS 37GHZ MICROWAVE IMAGE INDICATES A
WELL DEFINED LOW LEVEL CIRCULATION WITH THE MAJORITY OF DEEP
CONVECTION TO THE SOUTH OF THE LLCC. THE INITIAL POSITION IS PLACED
WITH MEDIUM CONFIDENCE BASED ON EIR AND SSMIS IMAGERY. THE INITIAL
INTENSITY OF 50 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE
PREPONDERANCE OF INTENSITY GUIDANCE INDICATING 45-57KTS.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: COMBINED STEERING INFLUENCE OF THE
NEAR-EQUATORIAL RIDGE (NER) TO THE SOUTHEAST AND A SUBTROPICAL
RIDGE (STR) TO THE NORTHEAST. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.5 - 55 KTS
   RJTD: T3.0 - 45 KTS
   RCTP: T3.0 - 45 KTS
   KNES: T3.0 - 45 KTS
   DEMS: T2.5 - 35 KTS
   CIMSS SATCON: 51 KTS AT 242226Z
   CIMSS ADT: 45 KTS AT 242330Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 15-20 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE EQUATORWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   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: TS 22W IS FORECASTED TO CONTINUE TRACKING
WESTWARD UNDER THE COMBINED STEERING INFLUENCES OF A NER TO THE
SOUTHEAST AND A STR TO THE NORTHEAST. WHILE THE OVERALL ENVIRONMENT
IS CHARACTERIZED AS MODERATELY FAVORABLE, PERSISTENT MID-UPPER LEVEL
VERTICAL WIND SHEAR IS FORECASTED TO PREVENT 22W FROM SIGNIFICANTLY
INTENSIFYING. OVER THE NEXT 36 HOURS THE SYSTEM WILL STILL CLIMB TO
55KTS AND POSSIBLY HIGHER AS IT TRANSITS THE BASIN. NEAR TAU 48, A
PASSING MID-LATITUDE TROUGH BREAKS DOWN THE STR WHILE AT THE SAME
TIME THE NER RIDGE IS BUILDING. THE RESULT OF THESE ATMOSPHERIC
FORCINGS IS THAT 22W IS FORECASTED TO MAKE AN ABOUT-FACE THROUGH
TAU  96 AND STEADY UP ON A RECIPROCAL COURSE, AND TRACK EASTWARD
INTO THE SCS. THROUGH THE ENTIRE COURSE CHANGE, VERTICAL WIND SHEAR
CONTINUES TO INCREASE BEYOND 45KTS, RESULTING IN A STEADY WEAKENING
TREND THROUGH TAU 120.

MODEL DISCUSSION: NUMERICAL MODELS ARE IN GOOD AGREEMENT THAT 22W
WILL APPROACH VIETNAM BEFORE TURNING SOUTH AND EVENTUALLY EASTWARD
THROUGH TAU 120. THE TIMING AND NATURE OF THIS TURN IS NOT AGREED
UPON HOWEVER. FOR THIS REASON, THE INITIAL JTWC TRACK FORECAST IS
PLACED WITH HIGH CONFIDENCE AND WITH LOW CONFIDENCE THEREAFTER.
RELIABLE MODEL INTENSITY GUIDANCE INDICATES GRADUAL INTENSIFICATION
THROUGH TAU 36 AND STEADY WEAKENING THEREAFTER. THE TRACK GUIDANCE
HAS AN IMMENSE IMPACT ON THE INTENSITY FORECAST DUE TO THE UNKNOWN
EXTENT OF LAND INTERACTION, BECAUSE OF THIS, THE JTWC FORECAST
INTENSITY IS PLACED INITIALLY WITH MEDIUM CONFIDENCE AND WITH LOW
CONFIDENCE THEREAFTER.

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