Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 227 AM EDT Mon Aug 05 2024 Valid 12Z Mon Aug 05 2024 - 12Z Wed Aug 07 2024 ..Hurricane Debby is expected to cause potentially catastrophic Flash and Urban Flooding, life-threatening storm surge, and strong winds across portions of Florida and the Southeast... ...There's potential for Excessive Rainfall and Severe Thunderstorms across portions of the Upper Midwest, Lower Great Lakes and Northeast through Tuesday... ...There are Excessive Heat Warnings over parts of Central/Southeastern California and the Southwest and Heat Advisories over parts of the Lower Mississippi Valley... Hurricane Debby will make landfall this morning over Florida's Big Bend region, where Hurricane Warnings are in effect. Life-threatening storm surge is possible along portions of Florida's Gulf Coast, where Storm Surge Warnings are in effect. Widespread thunderstorms are likely to continue across Florida and spread into Georgia and the Southeast Coast today. The Storm Prediction Center issued a Slight Risk of Severe Thunderstorms (level 2/5) for portions of northern Florida through southern/coastal Georgia and into South Carolina's central coast, where the chance for tornadoes is greatest. Elsewhere, Tropical Storm conditions are are expected along Florida's west coast including the Tampa Bay area today. Potentially historic heavy rainfall, associated with Hurricane Debby, across southeast Georgia and South Carolina through Friday morning will likely result in areas of catastrophic flooding. Heavy rainfall will likely result in considerable flooding impacts from portions of central and northern Florida through the Coastal Plains of the Carolinas through Friday. There are High Risks (at least 70%) of Excessive Rainfall stretching from Florida's Big Bend region up through coastal Georgia and into South Carolina's southern coast today followed by another on Tuesday along the Georgia--South Carolina Coastline. Anywhere between 7-15 inches of rain, with locally higher amounts, are possible from north-central Florida to South Carolina's northern coast over the next 48 hours. For more information go to hurricanes.gov. A slow moving cold front extending from the Northern High Plains to the Northeast will be the focus for scattered showers and thunderstorms across the northern tier states down to the Midwest and Mid-Atlantic over the next couple of days. Today, showers and thunderstorms are expected to develop and potentially produce severe thunderstorms and Excessive Rainfall over parts of the Upper Midwest and interior Northeast. Slight Risks of Flash Flooding (at least 15%) and Severe Storms are in effect over the aforementioned areas today. The threat for heavy rainfall shifts into the New York Tri-State area on Tuesday where another Slight Risk of Excessive Rainfall is in effect due to the potential involvement of tropical moisture from Debby. A low pressure system is expected to develop over the Northern High Plains of Montana on Tuesday and contribute to supercell/severe thunderstorm activity that evening. Severe wind gusts/hail will be the primary threats from these storms. High temperatures will likely remain well below average across the Northern Plains and Upper Midwest over the next several days, while Excessive Heat Risk grows across the Central Gulf Coast/Lower Mississippi Valley. Excessive Heat Warnings are in effect across the Desert Southwest and portions of California's southern/central Valley. Monsoonal storms are likely to continue across the Southwest and Four Corners region this week with a Slight Risk of Excessive rainfall over far south-central Arizona on Tuesday. Kebede Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php