ZCZC MIATCDEP3 ALL TTAA00 KNHC DDHHMM Hurricane Marie Discussion Number 15 NWS National Hurricane Center Miami FL EP132026 200 PM PDT Fri Sep 04 2026 Marie is contending with dry air today, which is likely inhibiting significant strengthening. A broad region of dry air persists immediately west of the hurricane, and recent infrared satellite imagery shows a dry slot wrapping from the southwest to the northeast around the center. This dry-air intrusion has substantially weakened the deep convection that was previously concentrated north and east of the eye. However, recent objective and subjective Dvorak intensity estimates range from 73-90 kt. The initial intensity is maintained at 85 kt for this advisory. The initial motion is 285/7 kt, with the hurricane moving along the southeastern periphery of a weak mid-level ridge centered between Marie and Hurricane Karina well to the west. A strong closed low moving into the Pacific Northwest today is expected to weaken this ridge and induce a turn toward the northwest tonight through this weekend. Through 72 h, the updated track forecast lies near the middle of the guidance envelope, and is closest to the Google DeepMind and HCCA. As Marie weakens early next week, the cyclone is expected to become increasingly steered by the low- to mid-level environmental flow. An eventual turn toward the north is possible by midweek as a new trough approaches the western U.S. Beyond 72 h, the forecast has been nudged to the right of the previous advisory, and Marie is expected to remain well offshore of the western United States. Marie is currently moving over warm waters of 27-28 C and through an environment of low wind shear, but dry mid-level air continues to take its toll on the hurricane. Increasingly unfavorable upper-level winds are expected to support very slow weakening over the next day or two, followed by more pronounced weakening early next week as Marie moves over cooler waters and into an increasingly dry mid-level environment. Simulated satellite imagery from the ECMWF and GFS suggests that Marie may struggle to maintain organized convection by the middle of next week. Accordingly, the latest NHC intensity forecast calls for Marie to degenerate into a post-tropical remnant low by day 5, with dissipation around day 6. FORECAST POSITIONS AND MAX WINDS INIT 04/2100Z 20.2N 118.6W 85 KT 100 MPH 12H 05/0600Z 20.9N 119.4W 80 KT 90 MPH 24H 05/1800Z 21.8N 120.5W 75 KT 85 MPH 36H 06/0600Z 22.6N 121.5W 70 KT 80 MPH 48H 06/1800Z 23.3N 122.3W 65 KT 75 MPH 60H 07/0600Z 24.0N 123.3W 60 KT 70 MPH 72H 07/1800Z 24.7N 124.5W 55 KT 65 MPH 96H 08/1800Z 26.6N 126.7W 40 KT 45 MPH 120H 09/1800Z 29.5N 128.2W 30 KT 35 MPH...POST-TROP/REMNT LOW $$ Forecaster Adams NNNN

WDPN31 PGTW 042100 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 22W (KROVANH) WARNING NR 015// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 28.4N 127.1E INITIAL INTENSITY: 45 KTS GEOGRAPHIC REFERENCE: 120 NM NORTH-NORTHWEST OF KADENA AB MOVEMENT PAST 6 HOURS: SOUTH-SOUTHWESTWARD AT 06 KTS SIGNIFICANT WAVE HEIGHT: 20 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TROPICAL STORM (TS) 22W WITH A PARTIALLY EXPOSED LOW-LEVEL CIRCULATION CENTER (LLCC) OBSCURED BY PERSISTENT CONVECTION IN THE NORTHEAST QUADRANT. THE SATELLITE PRESENTATION IN THE REMAINING QUADRANTS IS THAT OF STABLE LOW CLOUDS WRAPPING INTO THE SLIGHTLY ELONGATED LLCC. A ROBUST POLEWARD OUTFLOW CHANNEL SUPPORTED BY A PASSING JET STREAK IS STILL EVIDENT IN ANIMATED WATER VAPOR IMAGERY, WHICH CONTINUES TO SUPPORT CONVECTION IN THE NORTHEAST QUADRANT. A 041452Z OCEANSAT-3 SCATTEROMETRY IMAGE REVEALED THE HIGHLY ASYMMETRIC WIND FIELD AROUND THE CENTER OF THE SYSTEM, WITH A SWATH OF 45 KT WINDS IN THE NORTHERN SEMICIRCLE WHERE THE PRESSURE GRADIENT HAS ENHANCED THE WIND SPEEDS. THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON A COMBINATION OF THE POORLY DEFINED LLCC IN ANIMATED EIR AND EXTRAPOLATION FROM THE CENTER IN THE SCATTEROMETRY IMAGE. THE INITIAL INTENSITY OF 45 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE SCATTEROMETRY WINDS, HOWEVER, THE PRESSURE GRADIENT IS LIKELY RELAXING AS THE SYSTEM MOVES EQUATORWARD AND THEREFORE GRADUALLY REDUCING THE WIND SPEEDS IN THE NORTHERN SEMICIRCLE. THE ENVIRONMENT IS CHARACTERIZED AS MARGINAL, WITH WARM SEA SURFACE TEMPERATURES AND GOOD OUTFLOW ALOFT BEING OFFSET BY LOW-MODERATE VERTICAL WIND SHEAR (VWS) AND THE DRY AIR MASS SURROUNDING THE VORTEX IN ALL BUT THE NORTHEAST QUADRANT. INITIAL WIND RADII BASIS: SCATTEROMETER DATA CURRENT STEERING MECHANISM: SOUTHEASTERN FLANK OF A RIDGE POSITIONED OVER NORTHEAST CHINA AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T2.5 - 35 KTS RJTD: T2.0 - 30 KTS RCTP: T2.5 - 35 KTS KNES: T2.0 - 30 KTS CIMSS SATCON: 37 KTS AT 041704Z CIMSS ADT: 34 KTS AT 041750Z CIMSS AIDT: 38 KTS AT 041750Z CIMSS D-MINT: 35 KTS AT 041705Z CIMSS D-PRINT: 30 KTS AT 041820Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL VWS: 15-20 KTS SST: 29-30 CELSIUS OUTFLOW: STRONG POLEWARD OTHER FACTORS: SURROUNDING STABLE AND DRY AIR MASS ANALYSIS CONFIDENCE: INITIAL POSITION: MEDIUM INITIAL INTENSITY: MEDIUM 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 22W (KROVANH) HAS TRACKED SLOWLY SOUTHWESTWARD OVER THE PAST 6 HOURS AS THE DEEP SUBTROPICAL RIDGE (STR) OVER EASTERN CHINA HAS STARTED TO EXERT A STEERING INFLUENCE. THE TRACK IS FORECAST TO CONTINUE GENERALLY SOUTHWARD AS 22W APPROACHES OKINAWA, THEN CONTINUE AROUND A COUNTER-CLOCKWISE ARC TOWARD MINAMI-DAITOJIMA THROUGH TAU 60. A STR BUILDING IN FROM THE NORTHEAST IS EXPECTED TO INDUCE A POLEWARD TURN AND ACCELERATION AFTER TAU 60. THERE REMAINS A FAIR AMOUNT OF UNCERTAINTY IN THE TRACK DUE TO THE DYNAMIC NATURE OF THE STEERING ENVIRONMENT, ESPECIALLY IN THE LATER TAUS. IN TERMS OF INTENSITY, A GRADUAL DECREASE IS FORECAST THROUGHOUT THE ENTIRE PERIOD; FIRST AS A RESULT OF THE SYSTEM'S MOTION AWAY FROM THE ENHANCED GRADIENT TO ITS NORTH, THEN AS IT LOSES UPPER-LEVEL EXHAUST, CONTINUES TO INGEST DRY AIR, AND REMAINS IN AN UNFAVORABLE SHEAR ENVIRONMENT. MODEL DISCUSSION: MODEL TRACK GUIDANCE IS IN AGREEMENT ONLY INSOFAR AS THE GENERAL SHAPE OF THE ARCING TRACK AND THE EVENTUAL POLEWARD TURN. THE JTWC TRACK FORECAST REMAINS AMONG THE MEAN TRACK OF THE GUIDANCE THROUGHOUT THE FORECAST WITH M…

WDPN32 PGTW 042100 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 23W (TWENTYTHREE) WARNING NR 002// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 24.0N 137.1E INITIAL INTENSITY: 30 KTS GEOGRAPHIC REFERENCE: 234 NM WEST OF IWO TO MOVEMENT PAST 6 HOURS: NORTH-NORTHWESTWARD AT 17 KTS SIGNIFICANT WAVE HEIGHT: 15 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TROPICAL DEPRESSION (TD) 23W A LACK OF PERSISTENT CONVECTION AROUND THE POORLY ORGANIZED LOW-LEVEL CIRCULATION, THE REMNANTS OF WHICH ARE NOW FULLY EXPOSED. THERE IS AN APPARENT MESOVORTEX ROTATING WITHIN THE BROADER CYCLONIC WIND FIELD THAT MAY REPRESENT THE PREVIOUSLY OBSERVED COMPACT ROTATION. A 041510Z OCEANSAT-3 SCATTEROMETRY IMAGE REVEALED THE MESOVORTEX ON THE EASTERN EDGE OF THE BROADER CIRCULATION AND DEPICTED WIND SPEEDS OF 30-35 KTS IN THE SOUTHEAST QUADRANT. THE INITIAL POSITION IS PLACED WITH LOW CONFIDENCE BASED ON THE AMBIGUOUS STRUCTURE OF THE LOW-LEVEL CIRCULATION. THE INITIAL INTENSITY OF 30 KTS IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE SCATTEROMETRY DATA. THE ENVIRONMENT IS CHARACTERIZED AS MARGINAL FOR DEVELOPMENT, WITH WARM SEA SURFACE TEMPERATURES, LOW-MODERATE VERTICAL WIND SHEAR (VWS), AND WEAK OUTFLOW ALOFT. INITIAL WIND RADII BASIS: NOT APPLICABLE (THERE ARE NO INITIAL WIND RADII). CURRENT STEERING MECHANISM: WESTERN FLANK OF A SUBTROPICAL RIDGE CENTERED TO THE EAST AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T1.5 - 25 KTS KNES: T1.5 - 25 KTS CIMSS ADT: 41 KTS AT 041750Z CIMSS AIDT: 41 KTS AT 041750Z CIMSS D-PRINT: 27 KTS AT 041920Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL VWS: 15-20 KTS SST: 29-30 CELSIUS OUTFLOW: WEAK EQUATORWARD ANALYSIS CONFIDENCE: INITIAL POSITION: LOW 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 23W HAS TRACKED NORTH-NORTHWESTWARD OVER THE PAST 6 HOURS UNDER THE STEERING INFLUENCE OF THE STR TO THE EAST. THE TRACK IS FORECAST TO CONTINUE NORTH-NORTHWESTWARD TOWARD KYUSHU AT A RELATIVELY QUICK PACE FOR THE ENTIRE FORECAST PERIOD. THERE IS NOT EXPECTED TO BE ANY INFLUENTIAL INTERACTION WITH TROPICAL STORM 22W BASED ON THE LATEST GUIDANCE AND LACK OF DEVELOPMENT OF 23W. THE INTENSITY IS FORECAST TO STEADILY DECREASE AS THE SYSTEM EXITS A REGION OF ENHANCED SOUTHWESTERLY FLOW INTO AN UNFAVORABLE REGION FOR CONVECTIVE DEVELOPMENT. MODEL DISCUSSION: AVAILABLE MODEL TRACK GUIDANCE IS IN GOOD AGREEMENT ABOUT THE TRACK SPEED AND DIRECTION FOR THE ENTIRE FORECAST PERIOD. THE JTWC TRACK FORECAST IS PLACED CLOSE TO THE MULTI-MODEL CONSENSUS WITH HIGH CONFIDENCE. MODEL INTENSITY GUIDANCE FALLS WITHIN A 5 KT ENVELOPE AND DEPICTS A GRADUAL WEAKENING TREND, WITH THE EXCEPTION OF GFS, WHICH DEPICTS A BRIEF SPIKE TO 35 KTS. THE JTWC INTENSITY FORECAST FOLLOWS THE MULTI-MODEL CONSENSUS WITH HIGH CONFIDENCE. FORECAST CONFIDENCE: TRACK 00-72 HR: HIGH INTENSITY 00-72 HR: HIGH// NNNN