WDPN31 PGTW 192100 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 01W (ONE) WARNING NR 002// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 5.6N 157.8E INITIAL INTENSITY: 30 KTS GEOGRAPHIC REFERENCE: 82 NM SOUTH-SOUTHWEST OF POHNPEI MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 09 KTS SIGNIFICANT WAVE HEIGHT: 11 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS INCREASING DEEP CONVECTION AND CONVECTIVE BANDING DEVELOPING OVER AND TO THE NORTH AND EAST OF A CONSOLIDATING LOW LEVEL CIRCULATION CENTER EVIDENT IN RECENT MICROWAVE SATELLITE IMAGERY. THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON 191444Z GMI AND 191658Z SSMIS MICROWAVE SATELLITE IMAGERY. THE INITIAL INTENSITY OF 30 KTS IS ASSESSED WITH HIGH CONFIDENCE BASED ON MULTIAGENCY SUBJECTIVE DVORAK ESTIMATES, RECENT AUTOMATED DVORAK DATA, AND IN-SITU OBSERVATIONS. INITIAL WIND RADII BASIS: NOT APPLICABLE (THERE ARE NO INITIAL WIND RADII). CURRENT STEERING MECHANISM: LOW- TO MID-LAYER RIDGING TO THE NORTHEAST AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T2.0 - 30 KTS RJTD: T1.5 - 25 KTS KNES: T2.0 - 30 KTS CIMSS ADT: 28 KTS AT 191730Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE VWS: 5-10 KTS SST: 29-30 CELSIUS OUTFLOW: STRONG RADIAL ANALYSIS CONFIDENCE: INITIAL POSITION: MEDIUM INITIAL INTENSITY: HIGH INITIAL WIND RADII: NOT APPLICABLE 3. FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THE FORECAST PERIOD HAS BEEN EXTENDED TO 96 HOURS WITH A SLIGHTLY HIGHER PEAK INTENSITY AND LONGER ANTICIPATED DISSIPATION TIME FRAME. OTHERWISE, THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TD 01W WILL CONTINUE TRACKING NORTHWESTWARD TO NORTH-NORTHWESTWARD OVER THE NEXT 24 TO 36 HOURS UNDER THE CONTINUED STEERING INFLUENCE OF LOW- TO MID-LAYER RIDGING TO THE NORTHEAST OF THE SYSTEM. THEREAFTER, THE SYSTEM IS EXPECTED TO TURN INCREASINGLY WESTWARD AS SUBTROPICAL RIDGING BUILDS TO THE NORTH AND AS THE SYSTEM FALLS UNDER THE INFLUENCE OF LOWER-LEVEL FLOW DUE TO ANTICIPATED WEAKENING AND DISSIPATION. IN THE NEAR-TERM, ENVIRONMENTAL CONDITIONS INCLUDING LOW VERTICAL WIND SHEAR, HIGH SST AND RADIAL OUTFLOW ALOFT FAVOR INTENSIFICATION. THE WINDOW FOR DEVELOPMENT WILL BE LIMITED, HOWEVER, AS THE SYSTEM IS EXPECTED TO ENCOUNTER INCREASING SOUTHWESTERLY VERTICAL WIND SHEAR AND PRONOUNCED INTRUSION OF DRIER AIR ASSOCIATED WITH A SUBTROPICAL AIRMASS TO THE NORTH. WEAKENING TO BELOW THE WARNING THRESHOLD INTENSITY OF 25 KNOTS BY TAU 96 IS ANTICIPATED UNDER THESE INCREASINGLY UNFAVORABLE CONDITIONS. MODEL DISCUSSION: AVAILABLE NUMERICAL MODEL TRACK FORECAST GUIDANCE IS IN GOOD AGREEMENT REGARDING A GENERALLY NORTHWESTWARD TRACK IN THE NEAR-TERM FOLLOWED BY AND INCREASINGLY WESTWARD TRACK AFTER TAU 36. THE TWO OUTLIERS AMONG CONSENSUS MEMBERS, NAVGEM AND THE UKMET OFFICE MOGREPS ENSEMBLE MEAN, INDICATE SHARP NORTHWARD MOTION OVER THE NEXT 24 HOURS THAT IS INCONSISTENT WITH THE CURRENT STEERING PATTERN. THE TRACK FORECAST IS PLACE WITH MEDIUM CONFIDENCE WITHIN THE PRIMARY MODEL GROUPING, ADJUSTED SLIGHTLY TO THE SOUTH OF THE MULTI-MODEL CONSENSUS AS AN OFFSET TO THE LOW-PROBABILITY OUTLIERS. GLOBAL AND MESOSCALE DYNAMIC MODELS, INCLUDING HWRF AND COAMPS-TC, ARE IN GOOD AGREEMENT REGARDING THE INTENSITY FORECAST TREND. HOWEVER, SHIPS STATISTICAL-DYNAMICAL INTENSITY GUIDANCE INDICATES HIGHER INTENSITIES, WHICH REMAINS AS A LOW PROBABILITY OUTCOME IF THE SYSTEM VERY QUICKLY ORGANIZES OVER THE NEXT 24 HOURS OR SO AND HAS A BIGGER IMPACT ON ITS SURROUNDING ENVIRONMENT THAN CURRENTLY ANTICIPATED. THE INTENSITY FORECAST IS CONSISTENT WITH DYNAMIC MODEL GUIDANCE, BUT CONFIDENCE IS ONLY MEDIUM GIVEN SOME UNCERTAINTY REGARDING THE EXTENT OF DEVELOPMENT THAT WILL OCCUR OVER IN A FAVORABLE ENVIRONMENT OVER THE NEXT 24 HOURS. FORECAST CONFIDENCE: TRACK 0 - 72 HR: MEDIUM TRACK 72-120 HR: MEDIUM INTENSITY 0 - 72 HR: MEDIUM INTENSITY 72-120 HR: MEDIUM// NNNN