Area Forecast Discussion
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Issued by NWS
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078 FXUS62 KTAE 260834 AFDTAE Area Forecast Discussion National Weather Service Tallahassee FL 434 AM EDT Sun May 26 2024 ...New SYNOPSIS, NEAR TERM, SHORT TERM, LONG TERM, AVIATION, MARINE, FIRE WEATHER, HYDROLOGY... .SYNOPSIS... Issued at 434 AM EDT Sun May 26 2024 A late season cold front will limp across Alabama and Georgia on Monday afternoon and evening, supporting a round of strong to possibly severe thunderstorms, especially over Alabama, Georgia, and the inland Florida Panhandle. Following the front on Tuesday, a drier air mass will prevail for the rest of the week. && .NEAR TERM... (Today and tonight) Issued at 434 AM EDT Sun May 26 2024 Low-level southwest flow off the Gulf today will keep the seasonably muggy air mass in place. Meanwhile, upper ridging from the southwest will strengthen today. 500 mb heights near 5900 meters are possible in our FL counties. This will shut down convective development today. So this will mean a hot and dry afternoon ahead, and then a warm night ahead, especially at the coast. && .SHORT TERM... (Monday through Tuesday night) Issued at 434 AM EDT Sun May 26 2024 The tail end of the low-amplitude upper trough axis currently over the Southern Rockies will brush across the Southeast States late Monday. In response, a late season cold front will limp south through Alabama and Georgia. The air mass to its south will be characterized by moderate to strong convective instability, with the strongest instability over our AL/GA counties, where upper heights will fall the most. Precipitable Water (PW) values will also peak in the 1.6-1.9 inch range, which typically favors deep, moist convection. The incoming front will provide focus for thunderstorm development, along with iterative generations of southeast-propagating thunderstorm outflow boundaries. Westerly 500 mb flow of 30-40 knots will favor convective organization, at least into multi-cell clusters and possibly more. Isolated damaging wind gusts will be the main convective mode of concern. Indeed, SPC has upgraded the new Day 2 outlook to include a Slight Risk (Level 2 of 5) for our northernmost counties... along and north of an Enterprise AL to Albany GA line. As thunderstorms continue southeast into the FL Big Bend on Monday evening, the loss of daytime heating and increasing convective inhibition to the southeast will help storms weaken quickly after sunset. Behind the front on Tuesday, 1000-700 mb layer mean flow will become northwesterly. A drier air mass will trickle in. PW values will be drying out below the 1.5 inch value that serves as a loose threshold for deep, moist convection, and surface dewpoints will fall through the less convectively favorable and more comfortable 60s along and north of I-10. We could still eek out an isolated seabreeze storm from the Forgotten Coast over to the Nature Coast, but that would be about it. Of course, late season cold fronts do not really bring cooler air. Any improvement to human comfort is mainly due to drying and less mugginess, and the ensuing improvement in heat index. && .LONG TERM... (Wednesday through Saturday) Issued at 434 AM EDT Sun May 26 2024 Northwest flow aloft will prevail for the 2nd half of the week, though it will weaken late in the week as broad upper ridging slowly builds in from the southwest. Meanwhile, surface high pressure will move from the Upper Mississippi Valley to the coastal Carolinas. This will bring drying north and northeast breezes at the surface, which will gradually clock around easterly and southeasterly. These things favor a mostly dry forecast. Though daytime highs of 85-92 will be common, the drier air mass will allow late nights to cool into the 60s, except at the coast. && .AVIATION... (06Z TAFS) Issued at 434 AM EDT Sun May 26 2024 Low-level southwest flow will prevail for the next 24 hours, and upper ridging will strengthen over the region. This will maintain a moist low- level air mass, while suppressing any attempt at convection today. At 0730z, satellite imagery and surface obs showed low stratus and mist developing and expanding, especially along and west of the Flint Valley, including near ABY, DHN, and ECP. Expansion will continue through sunrise, with bases and visibility both lowering. So a few hours of IFR ceilings and at least some mist are expected at all terminals by sunrise. In typical fashion, conditions will improve rapidly starting about 2 hours after sunrise. Fair weather cumulus will prevail in the afternoon, with bases in the 035-050 range. && .MARINE... Issued at 434 AM EDT Sun May 26 2024 Gentle to moderate southwest breezes will prevail through Monday, in advance of a late season cold front that will slowly pass the waters on Monday night. Gentle to moderate westerly breezes will follow the front on Tuesday, followed by a northwest turn on Tuesday night. High pressure will pass by well north of the waters from Wednesday through Friday, causing winds to gradually clock around from northerly to easterly. && .FIRE WEATHER... Issued at 434 AM EDT Sun May 26 2024 Low-level southwest flow will prevail through Monday morning, and upper ridging will strengthen over the region. This will maintain a moist low- level air mass, while suppressing any attempt at convection today. On Monday afternoon, a late season cold front will make headway through Alabama and Georgia, supporting a round of strong afternoon thunderstorms with gusty and erratic winds. A turn to prevailing westerly breezes will follow on Tuesday, and a somewhat drier air mass will trickle in. As we approach the peak sun angles and length of daylight for the year, deep mixing is common in the afternoon. This will support pockets of high dispersion over inland districts each afternoon. Patchy fog is expected over many districts around sunrise this morning, and again on Monday morning. && .HYDROLOGY... Issued at 434 AM EDT Sun May 26 2024 Flood waters from heavy rainfall back on May 17 and 18 are now routing into the slow-responding Suwannee River, which will see rises in the days ahead. All other rivers continue to fall. Strong thunderstorms are expected on Monday afternoon, mainly over our Alabama and Georgia basins. Most places will not experience hydrologically significant rainfall, but isolated rainfall amounts of 2 to 3 inches are possible. This could bring localized short- duration runoff issues. && .SPOTTER INFORMATION STATEMENT... Spotter activation is not requested. However, spotters are always encouraged to safely report significant weather conditions when they occur by calling the office or tweeting us @NWSTallahassee. && .PRELIMINARY POINT TEMPS/POPS... Tallahassee 93 71 93 72 / 0 0 20 20 Panama City 86 76 87 75 / 0 10 20 20 Dothan 92 72 90 71 / 0 10 40 20 Albany 93 71 90 70 / 10 0 40 30 Valdosta 94 70 93 72 / 10 0 20 30 Cross City 91 68 90 72 / 10 0 0 20 Apalachicola 85 75 85 75 / 0 10 10 20 && .TAE WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AL...None. GM...None. && $$ NEAR TERM...Haner SHORT TERM...Haner LONG TERM....Haner AVIATION...Haner MARINE...Haner FIRE WEATHER...Haner HYDROLOGY...Haner