260 FXUS62 KTAE 100521 AFDTAE Area Forecast Discussion National Weather Service Tallahassee FL 1221 AM EST Sat Mar 10 2018 .AVIATION [Through 06Z Sunday]... VFR conditions expected through the period. Brief reductions in vsbys are not out of the question overnight at TLH and ABY due to FU/HZ. Otherwise, increasing mid/upper level clouds expected across the region through the day. && .PREV DISCUSSION [825 PM EST]... .NEAR TERM [Through Tonight]... 18 UTC surface analysis shows the area of high pressure is beginning to drift to the east of the region as light southerly flow is noted across the Western Florida Panhandle and into Southwestern Alabama. Where the core of the dry airmass remains in place from Tallahassee eastward, surface dewpoints have dropped into the upper teens and low 20s while air temperatures have warmed into the mid 60s. Overnight, the area of high pressure will continue drifting to the east of the region and be just east of the Florida Peninsula at daybreak. This sets up a challenging minT forecast overnight. With the local airmass still especially dry across the Florida Big Bend and portions of South Georgia, the potential is there after sunset for temperatures to quickly plummet. However, moisture return is already evident across the western half of the region, so only a small portion of our area is at risk for temperatures to get cold enough to support frost. MOS output at 12z was supportive of minT less than 36 degrees across the Florida Big Bend tonight, which is not surprising given this is where the driest air is located along with sandier soils, which improve radiational cooling. Additionally, since MOS has been too warm as of late, trended the overnight forecast toward the coldest of the MOS values. As a result, a frost advisory will be issued for the Florida Big Bend. .SHORT TERM [Saturday Through Sunday Night]... In the upper levels nearly zonal flow or a slight trough will be over the region. A major shortwave trough will approach the region Sunday night. At the surface a low will move across the Southeast this weekend. A cold front will move through the region on Sunday evening. POPs will begin increasing Saturday night ahead of the front. The best chance for rain and thunder will be Sunday afternoon and evening as the front approaches. There is a marginal threat for severe weather on Sunday. There are some model discrepancies on timing and instability. Dew points are forecast to be in the low to mid 60s by late Sunday morning. CAPE is forecast to be 500 to 1500 j/kg depending on which model is used. Deep layer shear will likely be 40 to 50 knots on Sunday. GFS has a clean frontal passage Sunday evening. The ECMWF and NAM models have showers lingering overnight. Temps will be warmer with highs in the 70s. Lows will be in the 50s Saturday night and in the 40s on Sunday night. .LONG TERM [Monday Through Friday]... Though the timing of the Sunday system is still somewhat uncertain, it should exit the region by mid-day Monday. Following the exit of this system, cooler and drier conditions will dominate the region for the rest of the period. Highs will stay in the low to mid 60s, with lows in the upper 30s and lower 40s. As high pressure enters the area late in the period on Friday, temperatures will warm slightly, with highs getting up to the upper 60s and lower 70s and lows from the mid 40s to mid 50s. .MARINE... Southerly winds will be moderate on Saturday and stronger Saturday night and Sunday morning. Sunday evening winds will become northwesterly and increase to 20 to 25 knots sustained as a cold front moves through. Northerly winds will remain elevated until Tuesday morning. Showers and thunderstorms are likely Saturday night through Sunday night. Some may be strong to severe. .FIRE WEATHER... RH values will increase this weekend, with showers expected Saturday night through Sunday across the region. Wind speeds will increase again Sunday as the system exits, but drier air won't really move in until Tuesday, so no red flag conditions are expected for the next several days. .HYDROLOGY... Local rivers are fairly steady and most are below action stage. Rain and thunderstorms are expected Sunday as a cold front approaches. Dry conditions are forecast thereafter. Less than one inch of rain is forecast over the next 7 days. No flooding concerns. .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 72 56 78 49 65 / 0 30 60 50 10 Panama City 71 63 74 51 63 / 0 40 50 40 10 Dothan 73 57 75 45 60 / 10 60 60 40 10 Albany 73 55 75 46 60 / 0 60 70 50 20 Valdosta 73 53 76 48 64 / 0 20 60 50 20 Cross City 73 55 76 52 67 / 0 20 60 40 20 Apalachicola 70 62 76 52 65 / 0 30 60 40 10 && .TAE WATCHES/WARNINGS/ADVISORIES... FL...Frost Advisory until 8 AM EST this morning for Gadsden-Inland Dixie-Inland Jefferson-Inland Taylor-Inland Wakulla- Lafayette-Leon-Liberty-Madison. GA...None. AL...None. GM...None. && $$ NEAR TERM...Fieux SHORT TERM...Godsey LONG TERM...McD AVIATION...Pullin MARINE...Nguyen FIRE WEATHER...McD HYDROLOGY...Nguyen