ZCZC MIATCDEP5 ALL TTAA00 KNHC DDHHMM Tropical Storm Simon Discussion Number 33 NWS National Hurricane Center Miami FL EP202026 800 AM MST Thu Oct 15 2026 First light visible imagery, along with GPM and AMSR-3 microwave data, show that the convective organization of Simon has changed a bit, with the main convection now in a band to the west of the center. The various subjective and objective satellite intensity estimates are in the 40-55 kt range and have not changed much during the past 6 h. Based on this, the initial intensity remains a possibly generous 50 kt. The microwave overpasses suggest the center of Simon is a little to the east of the previous advisory position, and it appears that the cyclone may be making a small loop in its track. Little motion is expected for the next 12 h or so as Simon remains embedded in an area of weak steering currents. After that time, a mid- to upper-level low is forecast to form near or west of the northern Baja California Peninsula while a weak mid-level ridge develops over northern and central Mexico. This should cause Simon to move northwestward near, but west of, the coast of Baja California Sur, and this motion is expected to continue until the system dissipates. The current track guidance is in better agreement in both direction and speed that it was 24 h ago, and the new forecast track lies near the center of the guidance envelope. The new forecast is a little to the east of the previous forecast through 60 h based mainly on the initial position, and after that it is close to the previous forecast. Given the new track forecast and the small size of Simon, wind watches are not needed for Baja California Sur at this time. The shear over Simon has decreased since yesterday, and it should remain light for the next 12-18 h. However, the storm is embedded is a dry air mass, so it likely will not be able to take advantage of the decreased shear. After 18 h, southerly and southwesterly upper-level winds are forecast to increase between the trough to the northwest of Simon and Hurricane Trudy to the southeast. This will result in strong shear over Simon that should cause the cyclone to weaken. The intensity forecast shows the system becoming a remnant low pressure area by 72 h and dissipating completely by 120 h, and global model guidance suggests these events could happen earlier than currently forecast. Key Messages: 1. Interests in Baja California Sur should continue to closely monitor the latest updates as Simon is expected to pass near or west of that area this weekend. 2. Large swells will likely affect portions of the coast of west-central Mexico and Baja California Sur over the next couple of days. These swells could cause life-threatening surf and rip current conditions. FORECAST POSITIONS AND MAX WINDS INIT 15/1500Z 19.2N 108.1W 50 KT 60 MPH 12H 16/0000Z 19.5N 108.1W 45 KT 50 MPH 24H 16/1200Z 20.2N 108.8W 45 KT 50 MPH 36H 17/0000Z 21.1N 110.0W 40 KT 45 MPH 48H 17/1200Z 21.9N 111.3W 35 KT 40 MPH 60H 18/0000Z 22.9N 112.6W 30 KT 35 MPH 72H 18/1200Z 24.0N 113.6W 25 KT 30 MPH...POST-TROP/REMNT LOW 96H 19/1200Z 26.8N 114.4W 20 KT 25 MPH...POST-TROP/REMNT LOW 120H 20/1200Z...DISSIPATED $$ Forecaster Beven NNNN

ZCZC MIATCDEP1 ALL TTAA00 KNHC DDHHMM Hurricane Trudy Discussion Number 9 NWS National Hurricane Center Miami FL EP212026 900 AM CST Thu Oct 15 2026 Trudy appears to be undergoing a period of rapid intensification. After the previous advisory, there were several microwave images that showed the hurricane has developed an eyewall, with a cyan ring noted on the 37 GHz channel of the 1037 UTC GMI and more recent 1250 UTC WSF-M pass. This signature is often a harbinger or indicates that rapid intensification is underway. On geostationary satellite Trudy has been maintaining a healthy central dense overcast with cold cloud tops between -75 to -80 C with new bursts of convection fully wrapping around the circulation as it becomes more symmetric. The subjective Dvorak estimate at 12 UTC was T4.5/77 kt, but given the improving structure seen on microwave imagery, the initial intensity is being set at 80 kt this advisory, which is on the high end of the intensity estimates. This indicates that Trudy has intensified 30 kt in the past 24 h, qualifying as rapid intensification. An Air Force Reserve Hurricane Hunter aircraft is en route to sample the hurricane and should provide critial in-situ data to help refine the forecast this afternoon. Trudy is now estimated to be moving slowly north-northwestward, or 335 degrees at 5 kt. Over the next 24-36 h Trudy is expected to maintain this heading but at a slow pace as its steering is maintained by two ridges, one to its east and another to its north. These features are split by a mid- to upper-level trough that is draped across the Yucatan Peninsula, weakening the overall steering flow. How these synoptic features interact over the next several days is leading to a lot of track uncertainty over the next few days, and there are some track solutions (GFS, ECMWF) that show Trudy making landfall. The latest NHC track forecast has been shifted eastward compared to the prior one, following the trends in the guidance. This track is blending the latest HFIP Corrected Consensus Approach (HCCA), Google DeepMind ensemble mean (GDMI) and also places a little weight on the latest ECMWF track forecast. With that said, given the spread of the deterministic and ensemble track guidance this cycle, this forecast is lower confidence than usual. Now that Trudy has developed an inner-core, intensification is likely to be rapid in the short-term. Environmental conditions are quite favorable (shear under 10 kt, sea-surface temperatures 28-29 C, and abundant moisture) and SHIPS-RI indices are elevated for a 30-40 kt increase in intensity over the next 24 h. Thus, the first part of this intensity forecast was raised from the previous advisory, showing Trudy becoming a major hurricane in 12-24 h, and peaking as a 125 kt Category 4 hurricane in 36 h. This part of the intensity forecast is on the upper end of the guidance. Thereafter, both the GFS and ECMWF based SHIPS guidance shows southwesterly vertical wind shear increasing markedly, and this will also be the period where Trudy nears the coast of Mexico, where terrain-induced effects will likely start to affect the circulation. These combined effects are now forecast to lead to weakening beginning in 48 h and continuing through the rest of the forecast. One big caveat with this intensity forecast is just how close Trudy gets to Mexico. A track closer to the coast may result in much more weakening than shown here, while a track further offshore may preserve Trudy's intensity, similar to what we saw with Simon earlier this week. The second part of the NHC intensity forecast falls back closer to the guidance mean. Given the proximity of Trudy's track to Mexico, this is also a lower confidence intensity forecast after the next 48 h. KEY MESSAGES: 1. Trudy is forecast to be a major hurricane as it approaches the coast of southwestern and west-central Mexico this weekend. There is an increasing risk of wind, rain, and storm surge impacts. A Tropical S…

WDPN32 PGTW 151500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 29W (CHAMPI) WARNING NR 005// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 11.0N 157.4E INITIAL INTENSITY: 35 KTS GEOGRAPHIC REFERENCE: 750 NM EAST OF ANDERSEN AFB MOVEMENT PAST 6 HOURS: WESTWARD AT 10 KTS SIGNIFICANT WAVE HEIGHT: 14 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS EXPLOSIVE DEEP CONVECTION PERSISTING ALONG THE WESTERN SIDE OF THE CIRCULATION WITH EXPANDING UPPER-LEVEL OUTFLOW. THE OVERSHOOTING CLOUD TOPS HAVE REACHED TEMPERATURES AS COLD AS -97 DEGREES CELSIUS. THE SYSTEM IS LIKELY STILL TILTED SOUTHWESTWARD WITH HEIGHT AND BATTLING MODERATE NORTHEASTERLY VERTICAL WIND SHEAR (VWS). HOWEVER, THE SYSTEM MAY BE BRIEFLY OVERCOMING THE EFFECTS OF VWS AS GRAVITY WAVES EMANATE RADIALLY FROM THE DEEP CONVECTION. MOST NOTABLY, THE LOW-LEVEL CIRCULATION CENTER (LLCC) HAS BECOME EMBEDDED IN THE NASCENT CENTRAL DENSE OVERCAST (CDO), WITH CURVED BANDING BEGINNING TO DEVELOP ALONG THE NORTHERN PERIPHERY. A 151025Z ASCAT-C PASS REVEALED AN ELONGATED LLCC WITH GALE-FORCE WINDS CONFINED TO THE SOUTHERN SEMICIRCLE. BASED ON THESE DATA AND THE IMPROVED CONVECTIVE STRUCTURE, 29W HAS BEEN UPGRADED TO A 35-KT TROPICAL STORM (TS) WITH HIGH CONFIDENCE. THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE, EXTRAPOLATED FROM THE SCATTEROMETER DATA AND HEDGED TOWARD THE NORTHEAST SIDE OF THE RAGGED CDO. THE ENVIRONMENT IS GENERALLY FAVORABLE FOR ADDITIONAL INTENSIFICATION, CHARACTERIZED BY VERY WARM SEA SURFACE TEMPERATURES (SST) OF 29-30 DEGREES CELSIUS, MODERATE UPPER-LEVEL DIVERGENCE FOCUSED ALONG THE WESTERN PERIPHERY, AND PLENTIFUL DEEP-LAYER MOISTURE. INITIAL WIND RADII BASIS: SCATTEROMETER DATA CURRENT STEERING MECHANISM: SOUTHERN FLANK OF A LOW- TO MID-LEVEL SUBTROPICAL RIDGE (STR) CENTERED NEAR 30N 160E AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T2.5 - 35 KTS RJTD: T2.5 - 35 KTS RCTP: T2.5 - 35 KTS CIMSS ADT: 41 KTS AT 151140Z CIMSS AIDT: 35 KTS AT 151140Z CIMSS D-MINT: 38 KTS AT 151148Z CIMSS D-PRINT: 40 KTS AT 151240Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE VWS: 15-20 KTS SST: 29-30 CELSIUS OUTFLOW: MODERATE WESTWARD ANALYSIS CONFIDENCE: INITIAL POSITION: MEDIUM INITIAL INTENSITY: HIGH INITIAL WIND RADII: HIGH 3. FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THE INTENSITY FORECAST HAS BEEN ADJUSTED UPWARD BY 5-10 KTS FROM TAU 12 TO TAU 72. FORECAST DISCUSSION: TS 29W IS MOVING WEST TO WEST-NORTHWESTWARD ALONG THE SOUTHERN PERIPHERY OF THE STR. THIS RIDGE WILL ERODE FROM TAU 24 TO TAU 48 AS A TROUGH PASSES WELL TO THE NORTH. MEANWHILE, A SHARP MID-LEVEL TROUGH APPROACHING THE KOREAN PENINSULA WILL SUPPORT THE DEVELOPMENT OF A NEW STR OVER HONSHU. THIS RIDGE WILL SETTLE EAST OF HONSHU NEAR TAU 72 AND BECOME THE PRIMARY STEERING MECHANISM FOR TS 29W, MAINTAINING A WEST-NORTHWESTWARD TRAJECTORY THROUGH TAU 120. THE RECENT EXPLOSIVE CONVECTION AND ONGOING VORTEX CONSOLIDATION MAY FORESHADOW SIGNIFICANT INTENSIFICATION ONCE AXISYMMETRIZATION IS ACHIEVED. VWS WILL EASE TOWARD TAU 60, WHILE TS 29W TRAVERSES VERY WARM SST OF 29-30 DEGREES CELSIUS. THE FORECAST CALLS FOR THE SYSTEM TO BECOME SUFFICIENTLY ORGANIZED TO BEGIN RAPID INTENSIFICATION (RI) NEAR TAU 36, REACHING TYPHOON STRENGTH SHORTLY THEREAFTER AND PEAKING AT 125 KTS AT TAU 96. ALTHOUGH THE ENVIRONMENT BECOMES EVEN MORE FAVORABLE AFTER TAU 72, CHARACTERIZED BY WARMER SST, HIGHER OHC, AND 5-10 KTS OF VWS, THE FORECAST CONSERVATIVELY LEVELS OFF THE INTENSITY AFTER TAU 96 TO ACCOUNT FOR DIFFICULT-TO-PREDICT FLUCTUATIONS IN INTENSITY CAUSED BY INTERNAL TROPICAL CYCLONE DYNAMICS. MODEL DISCUSSION: THE OVERALL TRACK GUIDANCE REMAINS TIGHT BUT HAS SHIFTED SOUTHWARD ONCE AGA…