Isaias, advisory 5
Tropical Storm Isaias Advisory Number 5
Public advisory
National Hurricane Center · public advisory 5 · issued Oct 7, 8:49 PM UTCsource ↗
000 WTNT34 KNHC 072049 TCPAT4 BULLETIN Tropical Storm Isaias Advisory Number 5 NWS National Hurricane Center Miami FL AL092026 400 PM CDT Wed Oct 07 2026 ...ISAIAS QUICKLY INTENSIFYING, FORECAST TO BE A HURRICANE BY THURSDAY MORNING... SUMMARY OF 400 PM CDT...2100 UTC...INFORMATION ---------------------------------------------- LOCATION...22.7N 92.9W ABOUT 225 MI...365 KM WNW OF PROGRESO MEXICO ABOUT 500 MI...805 KM SSW OF THE MOUTH OF THE MISSISSIPPI RIVER MAXIMUM SUSTAINED WINDS...65 MPH...100 KM/H PRESENT MOVEMENT...ENE OR 65 DEGREES AT 8 MPH...13 KM/H MINIMUM CENTRAL PRESSURE...994 MB...29.36 INCHES WATCHES AND WARNINGS -------------------- CHANGES WITH THIS ADVISORY: None SUMMARY OF WATCHES AND WARNINGS IN EFFECT: A Storm Surge Watch is in effect for... * Mouth of the Mississippi River to Yankeetown A Hurricane Watch is in effect for... * Bay St. Louis to Indian Pass A Tropical Storm Watch is in effect for... * Jefferson/Plaquemines Parish line to west of Bay St. Louis * East of Indian Pass to Aucilla River A Storm Surge Watch means there is a possibility of life- threatening inundation, from rising water moving inland from the coastline, in the indicated locations during the next 48 hours. For a depiction of areas at risk, please see the National Weather Service Storm Surge Watch/Warning Graphic, available at hurricanes.gov. A Hurricane Watch means that hurricane conditions are possible within the watch area. A watch is typically issued 48 hours before the anticipated first occurrence of tropical-storm-force winds, conditions that make outside preparations difficult or dangerous. A Tropical Storm Watch means that tropical storm conditions are possible within the watch area, generally within 48 hours. Interests in the Yucatan Peninsula of Mexico and elsewhere around the U.S. northern Gulf Coast should closely monitor the progress of this system. Additional watches and warnings could be required for a portion of the U.S. northern Gulf Coast tonight. For storm information specific to your area, including possible inland watches and warnings, please monitor products issued by your local National Weather Service forecast office. DISCUSSION AND OUTLOOK ---------------------- At 400 PM CDT (2100 UTC), the center of Tropical Storm Isaias was located near latitude 22.7 North, longitude 92.9 West. Isaias is moving toward the east-northeast near 8 mph (13 km/h). A continued east-northeastward motion is expected today, followed by a turn toward the northeast and north on Thursday and Friday. On the forecast track, Isaias is expected to pass to the north of the Yucatan Peninsula on Thursday and make landfall along the U.S. northern Gulf Coast late Friday or early Saturday. Maximum sustained winds are near 65 mph (100 km/h) with higher gusts. Isaias is forecast to become a hurricane by Thursday morning, with further strengthening expected through Friday morning. Tropical-storm-force winds extend outward up to 60 miles (95 km) from the center. The estimated minimum central pressure is 994 mb (29.36 inches) based on NOAA Hurricane Hunter dropsonde data. HAZARDS AFFECTING LAND ---------------------- Key messages for Isaias can be found in the Tropical Cyclone Discussion under AWIPS header MIATCDAT4 and WMO header WTNT44 KNHC. STORM SURGE: The combination of a dangerous storm surge and the tide will cause normally dry areas near the coast to be flooded by rising waters moving inland from the shoreline. The water could reach the following heights above ground somewhere in the indicated areas if the peak surge occurs at the time of high tide... Ocean Springs, MS to Indian Pass, FL...5-7 ft Mobile Bay...5-7 ft Mouth of the Mississippi River, LA to Ocean Springs, MS...3-5 ft Indian Pass, FL to Steinhatchee River, FL...4-6 ft Steinhatchee River, FL to Yankeetown, FL...2-4 ft Lake Pontchartrain...1-3 ft The deepest water will occur along the immediate coast near and to the east of the landfall location, where the surge will be accompanied by large and dangerous waves. Surge-related flooding depends on the relative timing of the surge and the tidal cycle, and can vary greatly over short distances. For information specific to your area, please see products issued by your local National Weather Service forecast office. For a complete depiction of areas at risk of storm surge inundation, please see the National Weather Service Peak Storm Surge Graphic, available at hurricanes.gov/graphics_at4.shtml?peakSurge. WIND: Hurricane conditions could begin in the Hurricane Watch area late Friday, and tropical storm conditions could begin in the watch areas by midday Friday. Gusty winds are possible in portions of the Yucatan Peninsula on Thursday. RAINFALL: Isaias is expected to produce rainfall amounts of 1 to 3 inches through Thursday across coastal portions of the eastern Bay of Campeche with isolated higher amounts possible in the states of Campeche and western Yucatan. From Friday through the weekend, the system is expected to produce rainfall amounts of 3 to 7 inches, with localized totals up to 10 inches, across the central U.S. Gulf Coast extending from far southeastern Louisiana to the Florida Panhandle. Rainfall amounts of 1 to 3 inches, with localized amounts up to 5 inches, are possible across much of the Southeast as far north as the Tennessee Valley and the Carolinas. Flash and urban flooding, along with isolated river flooding, will be possible. For a complete depiction of forecast rainfall associated with Tropical Storm Isaias, please see the National Weather Service Storm Total Rainfall Graphic available at hurricanes.gov/graphics_at4.shtml?rainqpf and the Flash Flood Risk graphic at hurricanes.gov/graphics_at4.shtml?ero TORNADO: Tornado potential will increase as rain bands accompanying Isaias approach the northeastern Gulf Coast Friday evening and overnight. This potential will spread inland on Saturday as Isaias continues northward. SURF: Swells are expected to affect the western and northern portions of the Yucatan Peninsula beginning on Thursday and spread northward toward the Gulf Coast late this week. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office. A depiction of rip current risk for the United States can be found at: hurricanes.gov/graphics_at4.shtml?ripCurrents NEXT ADVISORY ------------- Next intermediate advisory at 700 PM CDT. Next complete advisory at 1000 PM CDT. $$ Forecaster Blake
Forecast discussion
National Hurricane Center · forecast discussion 5 · issued Oct 7, 8:49 PM UTCsource ↗
000 WTNT44 KNHC 072049 TCDAT4 Tropical Storm Isaias Discussion Number 5 NWS National Hurricane Center Miami FL AL092026 400 PM CDT Wed Oct 07 2026 Satellite and aircraft data show that Isaias continues to strengthen. GOES-19 imagery indicates that a central dense overcast has formed, and the system has become more symmetric than this morning. The peak NOAA Hurricane Hunter aircraft 700-mb winds were 61 kt, with the pressure dropping to 994 mb. The initial intensity is set to 55 kt as a reflection of this data. Isaias is basically on track, moving east-northeast at 7 kt. There is no change to the synoptic reasoning as a deepening trough along the northwestern Gulf Coast and a strengthening Atlantic subtropical ridge should cause the system to move faster to the northeast tomorrow and northward on Friday. As long as the cyclone remains intact, it makes physical sense that the system will move on the faster and eastward side of the guidance due to the stronger shear Isaias should encounter near landfall. Thus, the new forecast is adjusted slightly to the east, closer to the AI-based and corrected-consensus models. NOAA radar data (P3-TDR) show that the system is experiencing some southwesterly shear, with tilt analyses displaying the mid-level circulation displaced 5-10 n mi to the northeast of the low-level center. This structure seems sufficient for further intensification given a continuation of similar low or moderate shear and very warm SSTs in a very humid environment. Models are fairly consistent about the shear increasing on Friday, but almost all guidance still shows a category 1 or 2 hurricane at landfall. While the regional hurricane models have generally come down on the peak intensity this cycle, it is unknown whether this is the start of a real trend, and we would prefer to see more than one guidance cycle before making any adjustments. The new forecast is close to the previous one, near the high side of the model suite. Key Messages: 1. Isaias is expected to strengthen and be a strong hurricane when it approaches the northern Gulf Coast on Friday. There is an increasing risk of life-threatening storm surge along portions of the northern Gulf Coast, and a Storm Surge Watch is in effect from The Mouth of the Mississippi River to Yankeetown, Florida. Residents in the watch area should follow advice given by local officials and evacuate if told to do so. 2. The risk of damaging hurricane-force winds is increasing over portions of the Florida Panhandle, southern Alabama, and southern Mississippi. A Hurricane Watch has been issued from Bay St. Louis, Mississippi, to Indian Pass, Florida. Residents in these areas should prepare for the possibility of long-duration power outages. 3. Isaias will bring areas of heavy rainfall to the central U.S. Gulf Coast and much of the Southeast Friday into the weekend. Flash and urban flooding, along with isolated river flooding, will be possible. 4. Isaias could bring gusty winds and areas of heavy rain to the western portion of the Yucatan Peninsula through Thursday. FORECAST POSITIONS AND MAX WINDS INIT 07/2100Z 22.7N 92.9W 55 KT 65 MPH 12H 08/0600Z 23.1N 91.8W 70 KT 80 MPH 24H 08/1800Z 24.1N 90.1W 80 KT 90 MPH 36H 09/0600Z 25.8N 88.7W 90 KT 105 MPH 48H 09/1800Z 28.1N 87.6W 95 KT 110 MPH 60H 10/0600Z 31.0N 87.3W 60 KT 70 MPH...INLAND 72H 10/1800Z 34.0N 87.5W 30 KT 35 MPH...POST-TROP/INLAND 96H 11/1800Z 37.5N 84.5W 15 KT 15 MPH...POST-TROP/INLAND 120H 12/1800Z...DISSIPATED $$ Forecaster Blake