Hydrometeorological Discussion
Issued by NWS
Issued by NWS
133 AGUS74 KWCO 041516 HMDNWC National Hydrologic Discussion - EXPERIMENTAL NWS National Water Center - Tuscaloosa AL 1015 AM CDT FRI OCT 4 2024 .Synopsis... Potential for multiple days of locally heavy rainfall in Florida and the Gulf Coast...A developing tropical disturbance in the Mariana Islands...Flash, urban and small stream flooding possible in Puerto Rico and the USVI...Lingering river flooding across the Southeast... .Discussion... Florida and the Gulf Coast... Tropical moisture will bring the potential for locally heavy rainfall today into the weekend and early next week. Given past rainfall from Hurricane Helene, soil conditions are still wet in portions of central and southern FL (0 - 10 cm RSM, 60-80%, NASA SPoRT) and streamflows are much above normal (USGS), suggesting that areas with the highest precipitation are likely to see at least localized impacts. The National Water Model (NWM) Medium-Range Forecast (MRF) continues to signal rapid-onset flooding potential from Tampa southward in both the NBM and GFS forced versions. Low annual-exceedance probabilities are present throughout central FL, from Tampa across the peninsula and as far south as Lake Okeechobee, suggesting a higher confidence in the location of possible significant streamflows. Mariana Islands... Moderate to locally heavy rainfall is forecast this weekend as a developing tropical disturbance brings the potential for flash and small stream flooding. There is still uncertainty with this system with regards to rainfall amounts and the likelihood of impacts. Puerto Rico and the USVI... Moderate to locally heavy rainfall bringing the potential for flash, urban and small stream flooding is forecast through early next week. .Southeast... Flows will continue to route downstream across the Coastal Plain of GA and the Carolinas through the weekend. The Santee river in SC, and the Ocmulgee, Alapaha, and Ogeechee rivers in GA will continue to rise over the next few days with crests expected by the weekend at most locations. No significant precipitation over the next week should allow for unimpeded recessions of elevated rivers across the region. //Kirkpatrick $$