ZCZC MIATCDEP3 ALL TTAA00 KNHC DDHHMM Hurricane Rachel Discussion Number 38 NWS National Hurricane Center Miami FL EP182026 800 AM PDT Tue Oct 06 2026 Satellite imagery this morning shows that Rachel's inner core has degraded, with the system now featuring a large, ragged eye. The deepest cold convection is confined mainly to the southern eyewall as the cyclone continues to encounter northeasterly wind shear and a drier mid-level environment. The latest subjective Dvorak intensity estimate from TAFB held steady at T4.5/77 kt, while objective intensity estimates from UW-CIMSS range between 77 and 82 kt. Based on these satellite trends and intensity estimates, the initial intensity is held at 75 kt for this advisory. The initial motion is westward, or 275/7 kt. A general west to west-northwestward motion is expected during the next several days while the system is steered by a subtropical ridge to its north. In a few days, a mid- to upper-level trough is forecast to approach the west coast of the United States, which will weaken the ridge. This should cause Rachel to slow down, make a sharp turn toward the northeast, and increase in forward speed. The latest NHC track forecast is very similar to the previous advisory and remains in good agreement with the HCCA and Google DeepMind aids. The surrounding environment is starting to take its toll on Rachel, with a drier, more stable airmass and moderate northeasterly wind shear. Sea surface temperatures along the forecast track will also cool below 26C in about a day or so, which should induce a steady weakening trend. Simulated infrared imagery from the global models shows Rachel struggling to produce deep, organized convection later this week. As a result, the latest NHC forecast now indicates that Rachel will become a post-tropical cyclone by 96 h. The official NHC intensity forecast is similar to the previous one, with gradual weakening near the upper end of the guidance suite in the short term, and then a faster weakening trend toward the consensus aids at the end of the period. FORECAST POSITIONS AND MAX WINDS INIT 06/1500Z 20.5N 119.5W 75 KT 85 MPH 12H 07/0000Z 20.6N 120.4W 75 KT 85 MPH 24H 07/1200Z 21.0N 121.7W 70 KT 80 MPH 36H 08/0000Z 21.5N 123.0W 60 KT 70 MPH 48H 08/1200Z 22.0N 124.3W 55 KT 65 MPH 60H 09/0000Z 22.4N 125.4W 50 KT 60 MPH 72H 09/1200Z 22.8N 125.8W 45 KT 50 MPH 96H 10/1200Z 24.2N 123.5W 40 KT 45 MPH...POST-TROPICAL 120H 11/1200Z 27.7N 119.3W 35 KT 40 MPH...POST-TROPICAL $$ Forecaster Kelly NNNN

WDPN31 PGTW 061500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 15E (NOLO) WARNING NR 064// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 25.4N 169.1E INITIAL INTENSITY: 100 KTS GEOGRAPHIC REFERENCE: 391 NM NORTH-NORTHEAST OF WAKE ISLAND MOVEMENT PAST 6 HOURS: WESTWARD AT 18 KTS SIGNIFICANT WAVE HEIGHT: 42 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTED THE SUDDEN AND DRAMATIC COLLAPSE OF TYPHOON (TY) 15E'S CENTRAL EYE JUST A FEW HOURS AGO. ADDITIONALLY, THE POLEWARD OUTFLOW CHANNEL IS COMPLETELY SUPPRESSED BY THE MODERATE TO HIGH (20-25 KTS) NORTHERLY VERTICAL WIND SHEAR (VWS). THE EQUATORWARD OUTFLOW CHANNEL REMAINS AVAILABLE, BUT INCREASINGLY WEAK. THE 061015Z ASCAT DATA REVEALS A TIGHT INNER CORE WITH AN ASYMMETRIC WIND FIELD. A THIN BAND OF STORM- AND TYPHOON-FORCE WINDS IS PRESENT ALONG THE SOUTHWESTERN SEMICIRCLE, CONTRASTED BY THE EXPANSIVE RANGE OF ELEVATED WINDS WITHIN THE NORTHEAST SEMICIRCLE. ENVIRONMENTAL ANALYSIS REVEALS A MARGINALLY UNFAVORABLE ENVIRONMENT, CHARACTERIZED BY MODERATE TO HIGH VWS, SIGNIFICANT DRY AIR ENTRAINMENT, MARGINAL (0-20 KJ PER CM SQUARED) OCEAN HEAT CONTENT (OHC), AND POOR OUTFLOW, OFFSET SLIGHTLY BY WARM (27-28 C) SEA SURFACE TEMPERATURES (SST). THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON THE COLLAPSED EYE IN ANIMATED EIR AND EXTRAPOLATION FROM THE 061015Z ASCAT DATA. THE INITIAL INTENSITY OF 100 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE AGENCY DVORAK FIXES AND THE CIMSS AUTOMATED INTENSITY ESTIMATES LISTED BELOW. INITIAL WIND RADII BASIS: ADJUSTED WIND RADII USING THE 061015Z ASCAT DATA CURRENT STEERING MECHANISM: DEEP-LAYER SUBTROPICAL RIDGE (STR) CENTERED TO THE NORTHWEST AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T5.0 - 90 KTS RJTD: T5.5 - 102 KTS RCTP: T5.5 - 102 KTS PHFO: T5.0 - 90 KTS CIMSS ADT: 97 KTS AT 061200Z CIMSS AIDT: 95 KTS AT 061200Z CIMSS D-PRINT: 90 KTS AT 061200Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY UNFAVORABLE VWS: 20-25 KTS SST: 27-28 CELSIUS OUTFLOW: WEAK EQUATORWARD OTHER FACTORS: DRY AIR ENTRAINMENT 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: TY 15E (NOLO) IS FORECAST TO CONTINUE TRACKING WESTWARD TO WEST-NORTHWESTWARD WHILE IT REMAINS ON THE EQUATORWARD PERIPHERY OF THE STR CENTERED TO THE NORTHEAST. BEGINNING AROUND TAU 48, 15E WILL TURN POLEWARD INTO A WEAK STEERING ENVIRONMENT CREATED BY A BREAK BETWEEN THE ROBUST STEERING STR AND A BUILDING LOW- TO MID-LEVEL RIDGE CENTERED OVER JAPAN. DURING THIS PERIOD, 15E IS FORECAST TO SLOW ITS TRANSLATIONAL SPEED. ULTIMATELY, 15E IS FORECAST TO DRIFT POLEWARD AND RECURVE ABOUT THE STEERING RIDGE THROUGH THE REMAINDER OF THE FORECAST PERIOD. TRANSITION INTO AN EXTRATROPICAL CYCLONE WILL BEGIN NO LATER THAN TAU 120. REGARDING INTENSITY, 15E IS FORECAST TO STEADILY WEAKEN THROUGH TAU 36-48 AS THE ENVIRONMENT REMAINS MARGINALLY UNFAVORABLE. BY ABOUT TAU 48, VWS IS EXPECTED TO ABATE SLIGHTLY, CONCURRENT WITH THE POLEWARD OUTFLOW CHANNEL STRENGTHENING AS THE STORM ENTERS THE WEAKNESS BETWEEN RIDGES. AS A RESULT, 15E IS ANTICIPATED TO REINTENSIFY SLIGHTLY BETWEEN TAU 60-72. AFTER TAU 72, VWS IS EXPECTED TO INCREASE, STIFLING THE POLEWARD OUTFLOW CHANNEL AND FORCING EXCESSIVE AMOUNTS OF DRY AIR INTO THE CORE. THE ENVIRONMENT WILL CONTINUE TO DETERIORATE AS NOLO TRACKS POLEWARD, ALONG WITH THE WEAK OUTFLOW, VWS, AND DRY AIR, IT IS EXPECTED TO CROSS THE 26C ISOTHERM AROUND TAU 96. BETWEEN TAU 96-120, 15E IS FORECAST TO BEGIN INTERACTION WITH THE UPPER-LEVEL WESTERLIE…

WDPN32 PGTW 061500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 26W (CHOI-WAN) WARNING NR 027// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 33.7N 147.6E INITIAL INTENSITY: 80 KTS GEOGRAPHIC REFERENCE: 402 NM EAST-SOUTHEAST OF YOKOSUKA, JAPAN MOVEMENT PAST 6 HOURS: NORTH-NORTHEASTWARD AT 23 KTS SIGNIFICANT WAVE HEIGHT: 42 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A GRADUALLY DEGRADING CONVECTIVE STRUCTURE ASSOCIATED WITH TYPHOON (TY) 26W. WHILE THE CENTRAL DENSE OVERCAST (CDO) AND CLOUD-FILLED EYE REMAIN EVIDENT, CLOUD TOP TEMPERATURES SURROUNDING THE CORE CONTINUE TO WARM, AND THE CONVECTIVE STRUCTURE OVER THE SOUTHWEST QUADRANT IS BEGINNING TO ERODE. A 061010Z GMI PASS REVEALED AN INTACT LOWER-LEVEL EYEWALL, WHILE INDICATING WEAKENING IN THE SOUTHERN PORTION OF THE UPPER-LEVEL EYEWALL. THE ENVIRONMENT IS LARGELY UNFAVORABLE AS THE SYSTEM CROSSES THE 26-DEGREE CELSIUS ISOTHERM INTO PROGRESSIVELY COOLER WATERS AND ENCOUNTERS HIGH VERTICAL WIND SHEAR (VWS). THESE DETRIMENTAL CONDITIONS OUTWEIGH THE FAVORABLE INFLUENCE OF STRONG POLEWARD OUTFLOW ALOFT. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE OUTLINE OF THE CLOUD-FILLED EYE IN THE SHORTWAVE INFRARED IMAGERY. THE INITIAL INTENSITY HAS BEEN LOWERED TO 80 KTS WITH MEDIUM CONFIDENCE, REFLECTING THE DETERIORATING SATELLITE PRESENTATION. THIS ASSESSMENT IS SUPPORTED BY THE T4.5 DVORAK CLASSIFICATION FROM PGTW AND THE DECREASING OBJECTIVE INTENSITY ESTIMATES LISTED BELOW. INITIAL WIND RADII BASIS: SCATTEROMETER DATA CURRENT STEERING MECHANISM: NORTHWESTERN PERIPHERY OF A SUBTROPICAL RIDGE (STR) CENTERED EAST OF HONSHU AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T4.5 - 77 KTS RJTD: T5.0 - 90 KTS RCTP: T5.0 - 90 KTS CIMSS ADT: 63 KTS AT 061140Z CIMSS AIDT: 67 KTS AT 061140Z CIMSS D-MINT: 73 KTS AT 061008Z CIMSS D-PRINT: 81 KTS AT 061210Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: UNFAVORABLE VWS: 30-40 KTS SST: 25-27 CELSIUS OUTFLOW: STRONG POLEWARD ANALYSIS CONFIDENCE: INITIAL POSITION: HIGH INITIAL INTENSITY: MEDIUM INITIAL WIND RADII: LOW 3. FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THE FORECAST HAS BEEN TRUNCATED FROM 36 HOURS TO 24 HOURS. FORECAST DISCUSSION: TY 26W IS NOW RACING NORTHEASTWARD AT 23 KTS ALONG THE NORTHWESTERN PERIPHERY OF THE STR. THE SYSTEM WILL CONTINUE TO ACCELERATE NORTHEASTWARD THROUGH TAU 24 AS IT BECOMES INCREASINGLY EMBEDDED IN STRONG DEEP-LAYER WESTERLY FLOW. THE ENVIRONMENT WILL BECOME INCREASINGLY HOSTILE TO THE TROPICAL CYCLONE, WITH VWS INCREASING TO 40-50 KTS AND SST DECREASING TO 14-16 DEGREES CELSIUS BY TAU 24. THESE FACTORS WILL CONTINUE TO ERODE THE INNER CORE, RESULTING IN STEADY WEAKENING. BAROCLINIC FORCING WILL ALSO INCREASE AS TY 26W INTERACTS WITH A MID-LEVEL TROUGH EJECTING EASTWARD FROM HONSHU AND BECOMES COUPLED WITH THE JET STREAM TO THE NORTH. THEREFORE, TY 26W WILL RAPIDLY COMPLETE EXTRATROPICAL TRANSITION BY TAU 24 WHILE MAINTAINING TYPHOON-FORCE WINDS. THE EXPANSIVE, POTENT WIND FIELD WILL PRODUCE VERY HIGH SEAS. MODEL DISCUSSION: TRACK GUIDANCE REMAINS IN EXCELLENT AGREEMENT, WITH MINIMAL CROSS-TRACK AND ALONG-TRACK SPREAD. THE JTWC FORECAST TRACK IS SET WITH HIGH CONFIDENCE NEAR THE MULTI-MODEL CONSENSUS (CONW) DUE TO THE TIGHT CLUSTERING OF THE GUIDANCE. INTENSITY GUIDANCE IS ALSO IN VERY GOOD AGREEMENT. ALL AVAILABLE AIDS DEPICT STEADY WEAKENING THROUGH TAU 24, AND THE JTWC INTENSITY FORECAST IS SET SLIGHTLY ABOVE THE CONSENSUS AT TAU 24, NEAR THE GFS SOLUTION. FORECAST CONFIDENCE: TRACK 00-72 HR: HIGH INTENSITY 00-72 HR: HIGH// NNNN

WDPN33 PGTW 061500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 27W (KOGUMA) WARNING NR 007// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 14.0N 165.8E INITIAL INTENSITY: 45 KTS GEOGRAPHIC REFERENCE: 321 NM SOUTH OF WAKE ISLAND MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 08 KTS SIGNIFICANT WAVE HEIGHT: 17 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A SMALL CENTRAL COLD COVER (CCC) COMPLETELY OBSCURING THE LOW-LEVEL CIRCULATION CENTER (LLCC). THE BURST OF CONVECTION HAS PERSISTED FOR AT LEAST SIX HOURS, AND CLOUD TOP TEMPERATURES HAVE BEEN AS COLD AS -92 DEGREES CELSIUS. THE CCC PATTERN IS CONSISTENT WITH ARRESTED DEVELOPMENT, SUPPORTING THE ASSESSMENT THAT THE INTENSITY HAS REMAINED NEARLY STEADY WHILE THE PATTERN PERSISTS. A 060649Z WSF-M MWI PASS INDICATED A VERTICALLY TILTED VORTEX AND A LACK OF A COHERENT INNER CORE. DESPITE TRAVERSING VERY WARM SEA SURFACE TEMPERATURES (SST) NEAR 30 DEGREES CELSIUS AND HIGH OCEAN HEAT CONTENT (OHC), TS 27W CONTINUES TO CONTEND WITH DRY AIR WRAPPING INTO THE CIRCULATION FROM THE SOUTHWEST AND MODERATE VERTICAL WIND SHEAR (VWS) OF NEAR 20 KTS. THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON A TIGHT CLUSTER OF FIXES FROM PGTW AND PHFO. THE INITIAL INTENSITY HAS BEEN HELD AT 45 KTS WITH MEDIUM CONFIDENCE, CONSISTENT WITH THE CCC CLOUD PATTERN AND SUPPORTED BY THE STEADY SUBJECTIVE AND LOWER-END OBJECTIVE ESTIMATES. THE HIGHER ADT ESTIMATE IS DISCOUNTED DUE TO THE TILTED VORTEX AND LACK OF A COHERENT INNER CORE. THE HIGH D-MINT ESTIMATE IS BASED ON A PARTIAL, LOW-RESOLUTION MICROWAVE IMAGE AND IS ALSO DISCOUNTED. INITIAL WIND RADII BASIS: PERSISTENCE CURRENT STEERING MECHANISM: SOUTHERN EXTENSION OF A MID-LEVEL SUBTROPICAL RIDGE (STR) BUILDING WESTWARD AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T2.5 - 35 KTS RJTD: T2.5 - 35 KTS RCTP: T3.0 - 45 KTS PHFO: T2.5 - 35 KTS CIMSS ADT: 53 KTS AT 061140Z CIMSS AIDT: 41 KTS AT 061140Z CIMSS D-MINT: 62 KTS AT 061045Z CIMSS D-PRINT: 45 KTS AT 061220Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE VWS: 15-20 KTS SST: 29-30 CELSIUS OUTFLOW: MODERATE WESTWARD OTHER FACTORS: DRY AIR ENTRAINMENT ANALYSIS CONFIDENCE: INITIAL POSITION: MEDIUM INITIAL INTENSITY: MEDIUM INITIAL WIND RADII: MEDIUM 3. FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TS 27W WILL CONTINUE ON A NORTHWESTWARD TRAJECTORY THROUGH TAU 12, STEERED BY THE SOUTHERN EXTENSION OF THE STR. THEREAFTER, THE SYSTEM WILL TURN WEST-NORTHWESTWARD AS THE MID-LEVEL RIDGE BUILDS WESTWARD. TOWARD THE END OF THE FORECAST PERIOD, A TROUGH TRAVELING EASTWARD FROM HONSHU WILL INTERACT WITH TYPHOON (TY) 15E TO CREATE A WEAKNESS IN THE STR, ALLOWING TS 27W TO TURN NORTHWESTWARD ON A MORE POLEWARD TRACK. THE EVOLUTION OF THE TROUGH, TY 15E, AND THE STR INTRODUCES SIGNIFICANT UNCERTAINTY REGARDING THE DEGREE OF THE POLEWARD TURN LATE IN THE FORECAST PERIOD. THE FORECAST CALLS FOR LIMITED DEVELOPMENT THROUGH TAU 12 DUE TO THE ONGOING CCC PATTERN, VWS, AND DRY AIR ENTRAINMENT. DESPITE TRAVERSING VERY WARM SST AND HIGH OHC, THE SYSTEM WILL INTENSIFY SLOWLY THROUGH TAU 36 AS MODERATE VWS PERSISTS. AFTER TAU 36, EASING SHEAR WILL ALLOW TS 27W TO RAPIDLY INTENSIFY TO A PEAK OF 110 KTS BY TAU 72. BY TAU 120, THE SYSTEM WILL WEAKEN SLIGHTLY DUE TO LOWER OHC. TS 27W HAS A COMPACT CIRCULATION AND IS PRONE TO SIGNIFICANT FLUCTUATIONS IN INTENSITY. IF THE VWS EASES SOONER AND TS 27W DEVELOPS A COHERENT INNER CORE MORE QUICKLY, THEN RAPID INTENSIFICATION (RI) COULD COMMENCE EARLIER AND LEAD TO A HIGHER PEAK INTENSITY THAN FORECAST. MODEL DISCUSSION: TRACK GUIDANCE …