Early Alert Informal | Subtropical Storm Alberto forms | 12:00 pm CDT - May 25, 2018:
EA Special Weather Hazards Brief: Subtropical Storm Alberto – Central Gulf Coast
Headlines:
…Subtropical Storm Alberto develops near the Yucatan Peninsula this morning…
…Will become the season’s first Tropical Cyclone later today or on Sat…
…A general track northward towards the central Gulf coast is forecast…
…Landfall is most likely from southeast LA to the western FL Panhandle on Mon…
…To make landfall a moderate to strong Tropical Storm…
…Flash flooding (some significant) and scattered power outages are possible…
Subtropical Storm Alberto Overview:
An area low pressure just east of the Yucatan Peninsula continues to become better organized over the last 12 hours and is now Subtropical Storm Alberto. Current forecast models develop the system into a tropical cyclone later today into on Sat while it tracks northward into the central Gulf of Mexico. Based on the current forecast, landfall as a moderate to strong Tropical Storm is forecast Mon afternoon/evening along the Central Gulf Coast. The potential for the system to become a weak Hurricane prior to landfall cannot be ruled out. Tropical Storm conditions are likely to begin impacting land late Sunday afternoon into Sunday evening and continue through Mon night before the system weakens into a tropical depression by Tue morning.
Rainfall Forecast:
- Conditions similar to this past week can be expected on Sat into Sunday morning with scattered showers and thunderstorms along the Gulf coast from LA through FL. The heaviest rainfall of 1-2 inches occurring in the southern FL Peninsula.
- Rain coverage will increase late Sunday afternoon into the evening from the FL Panhandle west to the mouth of the MS River as the system approaches.
- Widespread rainfall, heavy at times is expected from the mouth of the MS River east to western FL Peninsula on Mon morning, continuing through Mon night into Tue morning before diminishing Tue afternoon.
- The heaviest totals 4-8 (locally 12) inches and greatest risk for flash flooding (some significant) is forecast from southeast MS through southwest AL, and the western FL Panhandle including Gulfport, Pascagoula, Mobile, and Pensacola.
- Lesser amounts of 2-6 inches are forecast over far southeastern LA, eastern MS, the southern half of AL, the FL Panhandle, and southern GA, with localized flash flooding likely over this region.
- Across southwest FL and the Keys, while direct impacts from Alberto are not expected, associated tropical moisture will support periods of heavy rainfall with 3-6 inches forecast on Sat through Sunday afternoon. This could result in localized flash flooding.
Winds Forecast:
- Based on current forecasts the strongest winds will occur where the center of circulation makes landfall and just east of this point which is likely from coastal portions of southeast LA through southeast MS, southwest AL, and the western FL Panhandle.
- Winds in these locations of 40-65 mph sustained with gusts of 60-75 mph are likely which includes Slidell, Gulfport, Pascagoula, Mobile, and Pensacola.
- Inland areas of Southeast LA, southern MS, southern AL, and the central FL Panhandle can expect lesser winds of 25-35 mph with gusts of 40-55 mph.
Impacts:
- Flash flooding (some significant) with road closures especially where the heaviest rain falls
- Scattered power outages at the point of landfall and along the eastern edge of the system are likely.
- Impacted commutes late Sunday through Tue morning with lingering impacts due to flooding and power outages into Tue night and Wed.
- Rises on local rivers into Minor to Moderate Flood Stage in southern MS, southern AL, southwest GA, and the Western FL Panhandle.
Updates:
- Additional EA products will be issued as forecast conditions warrant.
- Please refer to the 6 hourly EA Tropical Cyclone Alerts for additional updated details on Subtropical Storm Alberto.
