Polo, advisory 4
Tropical Storm Polo Advisory Number 4
Public advisory
National Hurricane Center · public advisory 4 · issued Sep 21, 2:52 PM UTCsource ↗
000 WTPZ32 KNHC 211452 TCPEP2 BULLETIN Tropical Storm Polo Advisory Number 4 NWS National Hurricane Center Miami FL EP172026 900 AM CST Mon Sep 21 2026 ...POLO RAPIDLY INTENSIFYING OFFSHORE OF MEXICO... SUMMARY OF 900 AM CST...1500 UTC...INFORMATION ---------------------------------------------- LOCATION...15.4N 103.4W ABOUT 255 MI...410 KM SSE OF MANZANILLO MEXICO ABOUT 200 MI...320 KM SW OF ZIHUATANEJO MEXICO MAXIMUM SUSTAINED WINDS...65 MPH...100 KM/H PRESENT MOVEMENT...E OR 90 DEGREES AT 5 MPH...7 KM/H MINIMUM CENTRAL PRESSURE...997 MB...29.44 INCHES WATCHES AND WARNINGS -------------------- CHANGES WITH THIS ADVISORY: None. SUMMARY OF WATCHES AND WARNINGS IN EFFECT: A Tropical Storm Watch is in effect for... * Tecpan de Galeana to Punta San Telmo A Tropical Storm Watch means that tropical storm conditions are possible within the watch area, generally within 48 hours. The Tropical Storm Watch will likely be expanded westward later today or tonight. For storm information specific to your area, please monitor products issued by your national meteorological service. DISCUSSION AND OUTLOOK ---------------------- At 900 AM CST (1500 UTC), the center of Tropical Storm Polo was located near latitude 15.4 North, longitude 103.4 West. Polo is moving toward the east near 5 mph (7 km/h). A slow eastward or southeastward motion is expected through tonight. However, a sharp turn toward the west-northwest or northwest is expected by late Tuesday. On the forecast track, the core of Polo is expected to be near the coast of southwestern Mexico during the next few days. Maximum sustained winds have increased to near 65 mph (100 km/h) with higher gusts. Polo is expected to continue to rapidly intensify, becoming a hurricane by this afternoon and a major hurricane on Tuesday, with further intensification likely though midweek. Tropical-storm-force winds extend outward up to 70 miles (110 km) from the center. The estimated minimum central pressure is 997 mb (29.44 inches). HAZARDS AFFECTING LAND ---------------------- Key messages for Tropical Storm Polo can be found in the Tropical Cyclone Discussion under AWIPS header MIATCDEP2 and WMO header WTPZ42 KNHC. WIND: Tropical storm conditions are possible within the watch area by Tuesday night or early Wednesday. RAINFALL: Polo is expected to produce rainfall totals of 4 to 8 inches, with isolated maximum totals up to 12 inches across coastal portions of the Mexican states of Guerrero and Michoacn through Thursday. This rainfall may produce life-threatening flooding and mudslides, especially in areas of steep terrain. Rainfall of 3 to 6 inches is possible in coastal portions of Oaxaca, Colima, and Jalisco through Thursday. For a complete depiction of forecast rainfall associated with Polo, please see the National Weather Service Storm Total Rainfall Graphic available at hurricanes.gov/graphics_ep2.shtml?rainqpf SURF: Swells generated by Polo are expected to begin affecting portions of the coast of southwestern Mexico on Tuesday. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office. NEXT ADVISORY ------------- Next intermediate advisory at 1200 PM CST. Next complete advisory at 300 PM CST. $$ Forecaster Blake
Forecast discussion
National Hurricane Center · forecast discussion 4 · issued Sep 21, 2:53 PM UTCsource ↗
000 WTPZ42 KNHC 211453 TCDEP2 Tropical Storm Polo Discussion Number 4 NWS National Hurricane Center Miami FL EP172026 900 AM CST Mon Sep 21 2026 Polo is in the midst of a significant rapid intensification episode. Satellite images indicate a developing central dense overcast with very deep convection in the core. Additionally, microwave images indicate that a small eye has formed beneath the overcast with hints of a banded eyewall. The initial intensity is set to 55 kt, consistent with the latest TAFB classification, and a NOAA Hurricane Hunter aircraft is enroute to provide a better look at the intensity. Conditions look ideal for explosive intensification during the next day or two, with Polo's small inner core over very warm and untapped waters above 30.5C, within light shear and plentiful mid-level moisture. Every model responds to these conditions by showing rapid intensification, and the SHIPS rapid intensification index is showing percentages as high as I have ever seen them. The new forecast is raised from the previous one and is very aggressive, but still below the latest HCCA corrected-consensus aid, which verbatim would be at least a 99th percentile event for intensification. Polo is expected to be a small but very dangerous hurricane by tomorrow and beyond. The storm is drifting eastward, and still caught in weak steering currents. A mid-level ridge is expected to develop over Mexico by late Tuesday, causing Polo to move towards the west-northwest or northwest by Wednesday into late week. This could bring the core of the storm near or south of the coast of southwestern Mexico on Thursday, and then south of the Baja California Peninsula on Saturday. There is a large north-south spread in the guidance, which has both short and long-range implications. Generally, the guidance has nudged southward again, and the NHC forecast is adjusted in that direction. Given the spread in the track guidance, this is a low-confidence forecast. Key Messages: 1. Heavy rainfall associated with Polo will impact coastal portions of southwest Mexico through Thursday. This rainfall may produce life-threatening flooding and mudslides, especially in areas of steep terrain. 2. Polo is forecast to strengthen to a major hurricane while it moves closer to the coast of southwestern Mexico during the next few days. Although the core of the hurricane is forecast to stay offshore, it is too soon to determine the exact location or magnitude of impacts. Residents in southwestern Mexico should closely monitor its progress and updates to the forecast. A Tropical Storm Watch is in effect for portions of southwestern Mexico. FORECAST POSITIONS AND MAX WINDS INIT 21/1500Z 15.4N 103.4W 55 KT 65 MPH 12H 22/0000Z 15.2N 102.8W 85 KT 100 MPH 24H 22/1200Z 15.1N 102.3W 105 KT 120 MPH 36H 23/0000Z 15.4N 102.3W 125 KT 145 MPH 48H 23/1200Z 16.0N 102.8W 135 KT 155 MPH 60H 24/0000Z 16.8N 103.6W 140 KT 160 MPH 72H 24/1200Z 17.6N 104.8W 140 KT 160 MPH 96H 25/1200Z 18.6N 107.8W 130 KT 150 MPH 120H 26/1200Z 20.3N 110.4W 120 KT 140 MPH $$ Forecaster Blake
