WDPN32 PGTW 142100 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 29W (TWENTYNINE) WARNING NR 002// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 10.4N 160.5E INITIAL INTENSITY: 30 KTS GEOGRAPHIC REFERENCE: 950 NM EAST OF NAVSTA GUAM MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 11 KTS SIGNIFICANT WAVE HEIGHT: 12 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TROPICAL DEPRESSION (TD) 29W AS A PARTIALLY EXPOSED LOW-LEVEL CIRCULATION CENTER (LLCC) WITH A THIN PLUME OF CENTRAL DEEP CONVECTION SHEARED TO THE WEST. THERE IS A CONSIDERABLE AMOUNT OF DEEP CONVECTION DISPLACED WESTWARD OF THE CENTER, WITH DEEP CONVECTION BEGINNING TO BLOOM AROUND THE NORTHERN AND SOUTHERN PERIPHERIES. A PATCH OF DRY MID-LEVEL AIR TO THE NORTHEAST OF THE CENTER IS SUPPRESSING CONVECTION WITHIN THE EASTERN SEMICIRCLE. THE 141801Z SSMIS MICROWAVE DATA CONFIRMS THE SYSTEM REMAINS SHALLOW WITH THE CENTRAL CONVECTION DISPLACED TO THE WEST. ENVIRONMENTAL ANALYSIS REVEALS A FAVORABLE ENVIRONMENT, CHARACTERIZED BY WARM (29-30 C) SEA SURFACE TEMPERATURES (SST), ROBUST WESTWARD OUTFLOW, AND LOW TO MODERATE (15-20 KTS) EASTERLY VERTICAL WIND SHEAR, OFFSET SLIGHTLY BY THE REGION OF RELATIVELY DRIER AIR AND THE SLOW VORTEX CONSOLIDATION. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE MOSTLY EXPOSED LLCC. THE INITIAL INTENSITY OF 30 KTS IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE AGENCY DVORAK FIXES AND THE CIMSS AUTOMATED INTENSITY ESTIMATES LISTED BELOW. INITIAL WIND RADII BASIS: NOT APPLICABLE (THERE ARE NO INITIAL WIND RADII). CURRENT STEERING MECHANISM: THE SOUTHERN PERIPHERY OF THE DEEP-LAYER SUBTROPICAL RIDGE (STR) CENTERED FAR TO THE NORTH AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T2.0 - 30 KTS RJTD: T1.5 - 25 KTS CIMSS SATCON: 29 KTS AT 141720Z CIMSS ADT: 30 KTS AT 141910Z CIMSS AIDT: 27 KTS AT 141910Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE VWS: 15-20 KTS SST: 29-30 CELSIUS OUTFLOW: STRONG WESTWARD OTHER FACTORS: SMALL PATCH OF MID-LEVEL DRY AIR TO THE NORTHEAST ANALYSIS CONFIDENCE: INITIAL POSITION: HIGH INITIAL INTENSITY: HIGH INITIAL WIND RADII: NOT APPLICABLE 3. FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TD 29W RECENTLY CONCLUDED ITS LOOPING MOTION AND HAS TRACKED NORTH-NORTHWESTWARD FOR THE PAST SEVERAL HOURS. THE STORM IS FORECAST TO CONTINUE ITS NORTH-NORTHWESTWARD TRACK BRIEFLY THROUGH TAU 12. AFTER TAU 12, 29W IS EXPECTED TO ASSUME A STEADY NORTHWESTWARD TRACK FOR THE REMAINDER OF THE FORECAST PERIOD, WHILE IT REMAINS UNDER THE STEERING INFLUENCE OF THE EXPANSIVE STR CENTERED FAR TO THE NORTH. 29W IS FORECAST TO MAINTAIN A VERY CONSISTENT FORWARD MOTION THROUGH TAU 120, SUSTAINING A TRACK SPEED OF 13 KTS FROM TAU 12 TO TAU 72, BEFORE SLOWING SLIGHTLY TO 12 KTS BETWEEN TAU 72-120. REGARDING INTENSITY, 29W IS FORECAST TO GRADUALLY INTENSIFY THROUGH TAU 24 WHILE THE SYSTEM CONTINUES TO CONSOLIDATE AND ORGANIZE. FOLLOWING TAU 24, THE ENVIRONMENT IS EXPECTED TO BECOME MORE FAVORABLE, WITH VWS EXPECTED TO DROP TO 5-10 KTS AND THE DRY AIR BEGINNING TO REDUCE. IN RESPONSE TO THE IMPROVED CONDITIONS, 29W IS FORECAST TO STEADILY INTENSIFY FROM TAU 24 TO TAU 60. BY ABOUT TAU 60, THE ENVIRONMENT IS EXPECTED TO BECOME HIGHLY FAVORABLE, WITH THE DRY AIR ELIMINATED AND THE SYSTEM NOW STRONG ENOUGH TO EASILY RESIST THE PERSISTENT 10-15 KTS OF VWS. ADDITIONALLY, THE EQUATORWARD AND WESTWARD OUTFLOW IS EXPECTED TO STRENGTHEN AROUND TAU 36 AND REMAIN ROBUST THROUGH TAU 120, FURTHER AIDING IN INTENSIFICATION. THEREFORE, 29W IS FORECAST TO UNDERGO A PERIOD OF RAPID INTENSIFICATION (RI) BETWEEN TAU 60-96. JUST AFTER TAU 72, 29W IS EXPECTED TO PASS JUST OFF THE NORTHERN COAST OF GUAM, BRINGING ELEVATED WINDS TO THE NORTHERN MARIANAS ISLANDS. 29W IS EXPECTED TO PEAK AT TAU 120, WITH ADDITIONAL INTENSIFICATION POSSIBLE OUTSIDE THE FORECAST PERIOD. MODEL DISCUSSION: DETERMINISTIC MODEL TRACK GUIDANCE IS IN GOOD AGREEMENT THROUGH THE DURATION OF THE FORECAST PERIOD, THOUGH A FEW OUTLIERS ARE PRESENT: NAVGEM, GEFS, ECMWF, AND ECENS. DISCOUNTING THOSE MEMBERS, THE BULK OF THE MODEL GUIDANCE IS IN TIGHT AGREEMENT WITH A 75 NM CROSS-TRACK SPREAD AT THE CLOSEST POINT OF APPROACH TO THE NORTHERN MARIANAS (JUST AFTER TAU 72). THE JTWC TRACK FORECAST IS HEDGED SLIGHTLY SOUTH OF THE MULTI-MODEL CONSENSUS AND CLOSER TO GUAM, IN RESPONSE TO THE MOST RELIABLE MODEL SOLUTIONS DEPICTING A TRACK CLOSE TO THE NORTHERN COAST OF GUAM. THERE IS A MODERATE AMOUNT OF ALONG-TACK SPREAD CAUSED BY THE SAME GROUP OF MODEL OUTLIERS AS MENTIONED EARLIER (WITH THE EXCEPTION OF NAVGEM AND INCLUDING GSM). AS A RESULT, THE JTWC IS HEDGED SLIGHTLY FASTER THEN THE MULTI-MODEL CONSENSUS, CLOSE TO THE MOST RELIABLE MODEL SOLUTIONS. OVERALL, THE JTWC TRACK FORECAST LIES IN STRONG AGREEMENT WITH UKMET, GALWEM, AND THE FOLLOWING EXPERIMENTAL AL MODELS: GOOGLE DEEPMIND, AIGEFS, AIGFS, AIFS; WITH OVERALL HIGH CONFIDENCE. RELIABLE INTENSITY AIDS ARE IN STRONG AGREEMENT FROM TAU 0 UNTIL TAU 36, DEPICTING A GRADUAL INTENSIFICATION AS THE SYSTEM CONSOLIDATES, AND STRONGLY SUPPORTING THE JTWC INTENSITY FORECAST DURING THAT TIME. FROM TAU 36, GUIDANCE DIVERGES, WITH GOOGLE DEEPMIND INDICATING RI BEGINNING AS SOON AS TAU 36, AND HAFS-A INDICATING RI AS LATE AS TAU 72. THE TIMING OF THE RI PERIOD IS UNCERTAIN AND SOLELY DEPENDS ON HOW 29W IS ABLE TO CONSOLIDATE AND VERTICALLY ALIGN ITSELF. AS A RESULT, THE JTWC INTENSITY FORECAST IS ASSESSED WITH MEDIUM CONFIDENCE FROM TAU 0-72 AND LOW CONFIDENCE FROM TAU 72-120. THE JTWC INTENSITY FORECAST IS ALIGNED CLOSELY WITH COAMPS-TC AND HWRF THROUGH TAU 48, THEN HEDGED BETWEEN HWRF AND HAFS-A FROM TAU 60 TO 120. FORECAST CONFIDENCE: TRACK 00-72 HR: HIGH TRACK 72-120 HR: HIGH INTENSITY 00-72 HR: MEDIUM INTENSITY 72-120 HR: LOW// NNNN