ZCZC MIATCDEP2 ALL TTAA00 KNHC DDHHMM Tropical Storm Vance Discussion Number 19 NWS National Hurricane Center Miami FL EP222026 900 PM CST Sun Oct 25 2026 Vance's structure continues to degrade as seen in visible satellite imagery and the GPM and AMSR3 microwave passes, due to strong vertical wind shear and relatively dry mid-level air. Convection continues to develop to the northeast of the center, but it is mostly limited to that quadrant. The TAFB Dvorak fix was T3.5/55 kt and the objective intensity estimates from UW-CIMSS are in 37-52 kt range. Based on that data, the initial intensity has been lowered to 55 kt. Vance is currently moving toward the northwest, 305/6 kt. The tropical storm is being steered by a mid-level ridge centered over the south-central United States, along with a closed upper-level low moving across the southwestern United States. The cyclone is expected to continue to move toward the northwest to west-northwest with a decrease in forward speed as the steering currents weaken. A turn back to the north is expected by the middle of the week as an amplified mid to upper-level trough moves over the eastern Pacific. The current NHC track forecast has been adjusted a little to the west of the previous one. Future adjustments to the west are likely if the guidance trends continue. The combination of southwesterly wind shear and relatively dry mid-level air are expected to continue to gradually weaken the storm. By the middle of this week, an upper-level trough will further enhance the wind shear, resulting in additional weakening. Both the GFS and ECMWF simulated satellite imagery suggest that Vance will struggle to hold on to organized deep convection by late this week. The current intensity forecast still calls for Vance to become post-tropical at 96 h and degenerate into a remnant low by 120 h. However, the current intensity forecast is on the upper end of the guidance envelope, as most of the guidance shows the rate of weakening much faster than what is currently forecast. It is certainly possible that the cyclone could weaken faster, which will mean that it could become a remnant low sooner than what is forecasted. Key Messages: 1. Although the threat to southwest Mexico is decreasing as the forecast track shifts westward away from the coast, interests there should continue to monitor Vance's progress. 2. Periods of heavy rainfall associated with Vance will impact portions of western Mexico during much of this week. This rainfall may produce flooding and mudslides across Colima, Nayarit, and Sinaloa, along with western portions of Michoacán, Jalisco, and Durango, especially in areas along steep terrain. FORECAST POSITIONS AND MAX WINDS INIT 26/0300Z 15.0N 104.7W 55 KT 65 MPH 12H 26/1200Z 15.3N 105.3W 50 KT 60 MPH 24H 27/0000Z 15.7N 106.0W 45 KT 50 MPH 36H 27/1200Z 16.5N 106.8W 40 KT 45 MPH 48H 28/0000Z 17.4N 107.3W 40 KT 45 MPH 60H 28/1200Z 18.5N 107.6W 40 KT 45 MPH 72H 29/0000Z 20.0N 107.7W 40 KT 45 MPH 96H 30/0000Z 22.0N 107.8W 35 KT 40 MPH...POST-TROPICAL 120H 31/0000Z 24.0N 107.9W 30 KT 35 MPH...POST-TROP/REMNT LOW $$ Forecaster Katz/Cangialosi NNNN

WDIO31 PGTW 260300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 02B (TWO) WARNING NR 001// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 16.0N 89.1E INITIAL INTENSITY: 35 KTS GEOGRAPHIC REFERENCE: 398 NM SOUTH OF KOLKATA, INDIA MOVEMENT PAST 6 HOURS: WESTWARD AT 05 KTS SIGNIFICANT WAVE HEIGHT: 12 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TROPICAL CYCLONE (TC) 02B AS A CONSOLIDATING SYSTEM WITH STRONG DEEP CONVECTION WHICH IS BEGINNING TO WRAP AROUND THE CENTER. THE BULK OF THE DEEP CONVECTION IS LOCATED WEST OF CENTER, LEAVING LOW-LEVEL CLOUD BANDS PARTIALLY EXPOSED IN THE EASTERN HEMISPHERE. ENVIRONMENTAL ANALYSIS REVEALS A FAVORABLE ENVIRONMENT, CHARACTERIZED BY LOW (5-10 KTS) VERTICAL WIND SHEAR (VWS), WARM (29-30 C) SEA SURFACE TEMPERATURES (SST), AND STRONG WESTWARD OUTFLOW. THE INITIAL POSITION IS PLACED WITH LOW CONFIDENCE BASED ON LOW-LEVEL CLOUD BANDING IN ANIMATED MSI. THE INITIAL INTENSITY OF 35 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE PGTW DVORAK FIX AND AUTOMATED PRINT AND DMINT INTENSITY ESTIMATES LISTED BELOW. INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK CURRENT STEERING MECHANISM: THE EASTERN EXTENSION OF A SUBTROPICAL RIDGE (STR) CENTERED OVER SOUTHEAST ASIA AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T2.0 - 30 KTS CIMSS D-MINT: 33 KTS AT 252209Z CIMSS D-PRINT: 32 KTS AT 260100Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE VWS: 0-5 KTS SST: 29-30 CELSIUS OUTFLOW: STRONG WESTWARD ANALYSIS CONFIDENCE: INITIAL POSITION: HIGH INITIAL INTENSITY: HIGH INITIAL WIND RADII: MEDIUM 3. FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THIS INITIAL PROGNOSTIC REASONING MESSAGE ESTABLISHES THE FORECAST PHILOSOPHY. FORECAST DISCUSSION: TC 02B IS FORECAST TO CONTINUE TRACKING GENERALLY WESTWARD WHILE IT IS STEERED BY THE EXTENSION OF A STR CENTERED OVER SOUTHEAST ASIA. 02B IS EXPECTED TO MAKE LANDFALL SOUTHEAST OF VISAKHAPATNAM AROUND TAU 48, WITH DISSIPATION ANTICIPATED NO EARLIER THAN TAU 72. REGARDING INTENSITY, 02B IS EXPECTED TO REMAIN IN A FAVORABLE ENVIRONMENT FOR THE NEXT 12-24 HOURS, WITH VWS REMAINING LOW. AFTER TAU 24, VWS IS EXPECTED TO STEADILY INCREASE AND INDUCE DRY AIR ENTRAINMENT, HINDERING DEVELOPMENT AND WEAKENING THE STORM PRIOR TO LANDFALL. MODEL DISCUSSION: DETERMINISTIC MODEL TRACK GUIDANCE IS IN STRONG AGREEMENT THROUGH LANDFALL, SUPPORTING THE JTWC TRACK FORECAST WITH HIGH CONFIDENCE. RELIABLE INTENSITY AIDS ARE IN POOR AGREEMENT THROUGH TAU 48. SEVERAL JTWC RAPID INTENSIFICATION (RI) AIDS MET TRIGGER CRITERIA, INDICATING THE POSSIBILITY OF RI WITHIN THE NEXT 48 HOURS, WHICH COULD RESULT IN A SIGNIFICANTLY HIGHER PEAK THAN CURRENTLY FORECAST. THE PEAK INTENSITY RANGES FROM 55 KTS (GFS) TO 105 KTS (FRIA AND RIDE). THE JTWC INTENSITY FORECAST HEDGES ON THE CONSERVATIVE SIDE, ACCOUNTING FOR THE DEGRADING ENVIRONMENT AFTER TAU 24. THE JTWC INTENSITY FORECAST IS IN CLOSE AGREEMENT WITH COAMPS-TC AND THE MULTI-MODEL CONSENSUS WITH OVERALL LOW CONFIDENCE. FORECAST CONFIDENCE: TRACK 00-72 HR: HIGH INTENSITY 00-72 HR: LOW// NNNN

WDPN31 PGTW 260300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 30W (IN-FA) WARNING NR 011// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 13.8N 163.2E INITIAL INTENSITY: 85 KTS GEOGRAPHIC REFERENCE: 1014 NM EAST OF SAIPAN MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 08 KTS SIGNIFICANT WAVE HEIGHT: 30 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TYPHOON (TY) 30W AS A MUCH-IMPROVED SYSTEM WHEN COMPARED TO 6 HOURS AGO. THE UPPER- LEVEL CONVECTION IS FINALLY MAINTAINING PATCHES OF SUB-NEGATIVE 80 C CLOUD TOP TEMPERATURES, WHICH ARE WRAPPED AROUND THE CENTRAL AXIS. A NASCENT RAGGED EYE FEATURE IS FORMING IN THE ANIMATED BRIGHTNESS TEMPERATURES, WITH A CORRELATING DIMPLE IN THE ANIMATED MSI. THE 252230Z ASCAT PASS REVEALS A VERY COMPACT WIND FIELD, WITH TYPHOON- FORCE WINDS CONFINED TO WITHIN APPROXIMATELY 20 NM OF THE CORE. ENVIRONMENTAL ANALYSIS REVEALS A HIGHLY FAVORABLE ENVIRONMENT, CHARACTERIZED BY LOW (10-15 KTS) VERTICAL WIND SHEAR (VWS), WARM (29- 30 C) SEA SURFACE TEMPERATURES (SST), GOOD (100-125 KJ PER CM SQUARED) OCEAN HEAT CONTENT (OHC), AND STRONG POLEWARD OUTFLOW. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE NASCENT RAGGED EYE FORMING IN ANIMATED MSI. THE INITIAL INTENSITY OF 80 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE AGENCY DVORAK FIXES AND AUTOMATED CIMMS INTENSITY ESTIMATES LISTED BELOW. INITIAL WIND RADII BASIS: 262230Z ASCAT DATA CURRENT STEERING MECHANISM: A COMPETING STEERING ENVIRONMENT BETWEEN THE NORTHWESTERN FLANK OF A DEEP-LAYER NEAR-EQUATORIAL RIDGE (NER) TO THE SOUTHEAST AND A SUBTROPICAL RIDGE (STR) CENTERED TO THE NORTHWEST AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T5.0 - 90 KTS RJTD: T4.5 - 77 KTS RCTP: T4.5 - 77 KTS PHFO: T5.0 - 90 KTS CIMSS SATCON: 65 KTS AT 252200Z CIMSS ADT: 74 KTS AT 252330Z CIMSS AIDT: 73 KTS AT 260030Z CIMSS D-MINT: 70 KTS AT 252228Z CIMSS D-PRINT: 80 KTS AT 260000Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE VWS: 10-15 KTS SST: 28-29 CELSIUS OUTFLOW: STRONG POLEWARD ANALYSIS CONFIDENCE: INITIAL POSITION: HIGH 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 30W (IN-FA) IS FORECAST TO CONTINUE TRACKING FOR THE NEXT 12 HOURS WHILE IT REMAINS ON THE NORTHWESTERN PERIPHERY OF THE NER CENTERED TO ITS SOUTHEAST. THE SUBTROPICAL RIDGE (STR) TO THE NORTHWEST HAS STRETCHED EASTWARD, WHICH CREATED A COMPETING STEERING ENVIRONMENT, INDUCING A SLIGHT SLOWDOWN IN IN-FA'S NORTHWESTWARD TRACK. THE STR IS EXPECTED TO BUILD AND GAIN STEERING AUTHORITY BY TAU 24, WHICH IS EXPECTED TO CAUSE 30W TO ACCELERATE WEST-NORTHWESTWARD THROUGH THE TAU 72. BETWEEN TAU 48-60, AN UPPER- LEVEL TROUGH IS EXPECTED TO PASS NORTH OF THE STR, FORCING THE RIDGE TO RETREAT EASTWARD AND INDUCING A NORTHWESTWARD TRACK FOR 30W BETWEEN TAU 96-120 AS IT BEGINS TO CURL AROUND THE RIDGE'S SOUTHEASTERN PERIPHERY. REGARDING INTENSITY, 30W IS ASSESSED TO BE RAPIDLY INTENSIFYING, AND IS FORECAST TO CONTINUE RI THROUGH TAU 12. AT AROUND TAU 12, THE COMPETING STEERING ENVIRONMENT IS ANTICIPATED TO TEMPORARILY HALT INTENSIFICATION AS THE PROBABILITY FOR ADVERSE IMPACTS OF UPWELLING INCREASES. ONCE 30W TRANSITIONS STEERING ENVIRONMENTS AND BEGINS TRACKING WEST-NORTHWESTWARD, THE ENVIRONMENT WILL REMAIN FAVORABLE, SUPPORTING A SECOND ROUND OF INTENSIFICATION. AS 30W GAINS INTENSITY, IT MAY UNDERGO AN EYEWALL REPLACEMENT CYCLE (ERC), WHICH WOULD INDUCE TEMPORARY WEAKENING AND EXPAND THE WIND FIELD. AT LEAST ONE ERC IS DEPICTED IN THE HAFS-A MODEL GUIDANCE BETWEEN TAU 24-60, BUT MORE ARE…