Area Forecast Discussion
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Issued by NWS
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165 FXUS62 KTAE 090202 AFDTAE Area Forecast Discussion National Weather Service Tallahassee FL 1002 PM EDT Wed May 8 2024 ...New UPDATE, MARINE... .UPDATE... Issued at 950 PM EDT Wed May 8 2024 On the forecast update, have added patchy fog to our Big Bend and south-central GA counties late tonight and around sunrise. The dewpoint of 78F at Buoy 42036 suggests a favorable environment for fog as the moister air moves northeast overnight. Otherwise, the latest HRRR runs are speeding up the timing with the first round of storms coming in from the north tomorrow afternoon. && .NEAR TERM... (Through Thursday) Issued at 344 PM EDT Wed May 8 2024 The gusty winds will calm down this evening and the overnight hours. Temperatures tonight will fall to the low 70s. More clouds will filter in during the overnight hours. Patchy fog may be possible but not expected to be widespread as it has been for the past couple of mornings. For Thursday: The upper level ridge over the Gulf will flatten through the day as mid-level perturbations traverse east over Alabama and Georgia ahead of a strong cold front. Our northernmost counties will likely see thunderstorms during the afternoon hours on Thursday. Thursday afternoon and evening is expected to be quite active as the environment will be favorable for severe weather. Instability will be elevated with CAPE ranging between 1000-2000 J/kg and deep-layer shear around 35-45 kts and steep lapse rates. These parameters will be conducive to strong to destructive wind gusts (up to 75 mph), large hail, and a few tornadoes. The storm mode looks to approach the region as a squall line moving south through the afternoon hours and evening hours. Because of these threats, the SPC has upgraded the risk for our northern AL and GA counties (Tifton, GA to Enterprise, AL) to an Enhanced (3 of 5) risk for severe weather Thursday afternoon through the night. From that line down to I-10, these areas are included in a Slight (2 of 5) risk for severe weather. The threats are the same, but the amount of coverage for this area is less from numerous storms to scattered storms. South of I-10 to the coast is in a Marginal (1 of 5) risk for severe storms. There is also a heavy rain threat for our northwest counties, hence the WPC highlighted the area in a Marginal (1 of 4) risk for excessive rainfall. The Enterprise, AL to Dawson, GA line has a forecast PWAT greater than 1.75". The northern most part along that line is clipped into a Slight (2 of 4) risk for excessive rainfall. PoPs for Thursday afternoon range from 30-60 percent for areas north of I-10. South of I-10 has about a 20% chance for showers and thunderstorms. Timing of storms: We expect an overall three rounds of storms for Thursday afternoon, the second round happening Thursday night into Friday, and the third happening around daybreak Friday. Round 1 storm timing will begin around 12pm ET for our northern counties in AL and GA, moving south during the afternoon through the evening. Round 2 will have the greatest risk for severe storms, which will be discussed in the short term. Not everyone will see showers and thunderstorms on Thursday, so temperatures are still expected to rise to the low 90s, as storms are not expected until the late afternoon. Heat indices for areas around the I-75/I-10 corridor will be in the upper 90s. && .SHORT TERM... (Thursday night through Friday night) Issued at 344 PM EDT Wed May 8 2024 The main story will be the potential for severe weather. The D2 forecast from SPC added an Enhanced Risk for severe weather from about Berrien Co GA to Coffee Co AL northwards, south of that line, a Slight Risk of severe weather to about I-10, with a marginal risk dipping down into the the coastal counties and most the FL Big Bend. The situation is a one-two punch for severe weather. The first round could be an MCS dropping into SW GA from the north which is talked about in the near term. Then we have the main event Thu night into Friday where we could have a squall line come through. This is expected to be the larger event where we could see numerous severe storms capable of producing damaging and potentially destructive winds, large hail, and even embedded tornadoes. There is the potential for a third event / squall line Friday afternoon which will be dependent on boundaries and prior convective systems. && .LONG TERM... (Saturday through Tuesday) Issued at 344 PM EDT Wed May 8 2024 We will be post frontal by Saturday with high pressure building in for the weekend. Northerly winds will usher in cooler air to the region, placing highs in the upper 70s and low 80s for the GA and AL counties, and in the low to mid 80s in FL. The reprieve in temperatures will continue overnight with lows falling into the mid to upper 50s for most of the region. Warming returns on Sunday with highs in the low to mid 80s. By early next week the pattern looks to change and become wet again. Another shortwave looks to move across the northern Gulf states with our region possibly being impacted on Tuesday as winds turn to being southeasterly. With this shortwave possibly moving overhead, a stationary boundary to our south, left behind from the previous system, and a low-level wind field again around 30-45 kts, the potential for severe is once again present as well as the threat for heavy rain. We`ll have to see how this progresses over the next few days to have better confidence, be sure to come back for updates. && .AVIATION... (00Z TAFS) Issued at 745 PM EDT Wed May 8 2024 Similar to the last few evening, stratocumulus clouds with bases of 010-015 are gathering along the Panhandle coast. They will move and spread inland after sunset, bringing IFR cigs and reduced vsbys as we move through the night and get out to sunrise. Clouds will lift and scatter during the hours after sunrise. On Thursday afternoon, a large cluster of thunderstorms will move southeast through eastern Alabama and Georgia, possibly slipping south of the Florida state line while weakening late in the valid period. && .MARINE... Issued at 950 PM EDT Wed May 8 2024 An Atlantic ridge axis across the southern Florida Peninsula will retreat southward on Thursday. A cold front will slowly approach from the north on Friday, preceded by strong to severe thunderstorms over the waters. The front will limp across the waters on Friday night. It will be followed by moderate to occasionally fresh northerly breezes on Saturday morning. Surface high pressure over the southern Plains on Saturday will move across the Southeast States on Sunday, causing winds to clock around. High pressure will move east into the Atlantic on Monday, and low pressure will deepen over the Southern Plains. && .FIRE WEATHER... Issued at 344 PM EDT Wed May 8 2024 Wetting rains and severe storms are expected for our northern GA districts Thursday afternoon through Friday. All regions are expected to receive a wetting rain from early Friday through the afternoon. Along with the rain; gusty, damaging winds are expected in thunderstorms, with large hail, and possible tornadoes. Outside of rain and thunderstorms, high dispersions are expected for Thursday afternoon for areas south and east of the storms. So, along the I-75 corridor will have dispersion indices around 75 units. Mixing heights will be around 4000 feet. The cold front will pass through during the day on Friday, shifting the winds northerly by Friday night. Dispersions will increase to about 60-70 units with the front on Friday afternoon for our northwestern most counties. Elevated dispersions are expected for Saturday afternoon with northerly winds and dry conditions. The MinRH for Saturday will be around 35-40%. && .HYDROLOGY... Issued at 344 PM EDT Wed May 8 2024 The forecast generally remains on track with a Slight Risk clipping our extreme northern counties in AL and GA for Excessive Rainfall with a Marginal Risk extending from Ben Hill Co in GA to Geneva Co in AL. For Friday, the Marginal Risk is expanded south clipping most of the CWA. Moisture looks to be bountiful with PWATs around 2 inches or so. The main concern looks to be with flash flooding if storms move slowly or train. && .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 73 93 72 85 / 10 20 30 80 Panama City 75 86 73 83 / 20 20 30 70 Dothan 73 90 70 83 / 10 50 50 80 Albany 72 92 69 84 / 10 50 50 80 Valdosta 71 92 72 85 / 10 30 40 90 Cross City 69 87 71 85 / 0 10 20 80 Apalachicola 75 83 73 82 / 10 10 20 60 && .TAE WATCHES/WARNINGS/ADVISORIES... FL...High Rip Current Risk until 8 AM EDT /7 AM CDT/ Thursday for FLZ108-112-114-115. GA...None. AL...None. GM...None. && $$ NEAR TERM...Montgomery SHORT TERM...KR LONG TERM....KR AVIATION...Haner MARINE...Haner FIRE WEATHER...Montgomery HYDROLOGY...Haner