Area Forecast Discussion
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166 FXUS62 KTAE 181342 AFDTAE AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 842 AM EST Tue Nov 18 2014 ...A Hard Freeze with Record Cold Temperatures Expected Tonight... .Near Term [Through Today]...
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The 7 am EST regional surface analysis showed the strong cold front that passed through our forecast area on Monday was across South FL, with a large high pressure ridge building eastward across the Gulf Coast states. Vapor imagery and upper air data showed a large, unusually deep 500 mb trough over the eastern CONUS. The 7 am EST Tallahassee upper air sounding had the top of the arctic airmass only at about 2200 ft AGL, so it`s very shallow. Although the strongest low-level cold air advection has already occurred, the strong inversion atop the shallow cold air will limit vertical mixing, helping to keep high temperatures only in the mid to upper 40s. (That`s 20 to 25 deg below average, despite plenty of sunshine).
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&& .Aviation... [Through 12Z Wednesday] VFR conditions will prevail through the period with gusty winds from the north during the day that will start to settle by around 23Z. && .Prev Discussion [626 AM EST]...
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.Short Term [Tonight Through Thursday]... The massive long wave trough dominating much of North America will reach its greatest amplitude across the eastern U.S. tonight as one final short wave moves through its base across the northern Gulf of Mexico. Meanwhile, the high pressure center of the Arctic air mass that has arrived in the area will build east to a position near the AL/GA border by 12Z Wednesday. The position of the high should allow the boundary layer to decouple with calm winds the result. While there may be a few high clouds around, they do not figure to have much moderating affect on temperatures. Forecast lows have not changed appreciably. We are still looking for most inland areas to bottom out in the lower 20s with the coldest locations seeing upper teens. Even FL Panhandle beaches will see several hours of freezing temperatures. Inland areas will see freeze durations of 10-14 hours. The hard freeze watch will be upgraded to a warning. This is an exceptionally cold outbreak for November and we expect to shatter the daily records for the 19th at TLH (25 degrees in 2008) and AAF (33 degrees the same year). In fact, if the low of 20 degrees predicted for TLH is realized, it will be the coldest temperature ever recorded this early in the season. In this very dry air mass, temperatures will rebound quickly and will see highs some 10 degrees higher than today. However, they will still be about 16-17 degrees below normal. Another widespread freeze is expected Wednesday night. In fact, parts of the inland FL Big Bend could see another hard freeze. Max temps on Thursday will jump an other 10 degrees over the previous day`s numbers and generally be in the mid 60s. .Long Term [Thursday Night Through Tuesday]... The warming trend will continue through the weekend as heights rise and surface high pressure moves off to the east. In fact, we will actually see temps up around seasonal levels by Sunday. The weekend will also feature low pressure over TX on Saturday lifting quickly northeastward to the Great Lakes on Sunday. This system will bring a front into the region on Sunday with increasing chances for thunderstorms. Another front will then maintain rain chances into Monday. Initial indications are that there will be at least some marginal potential for severe weather with these systems. .Marine... With the strong cold front now well south of the forecast area, blustery north winds are sustained at small craft advisory levels this morning. While we have seen occasional gusts over 30 kt, frequent gusts to gale force are no longer anticipated and the warning will be cancelled. Winds over the nearshore legs will drop below advisory criteria by this afternoon with the offshore legs to follow overnight. As high pressure builds east along the Gulf Coast, winds will continue to subside on Wednesday. Light to moderate northeast to east winds will then persist across the Northeast Gulf through the end of the work week. Easterlies may reach cautionary levels on Saturday. .Fire Weather... A very dry, cold air mass will be in place over the area Tuesday and Wednesday with gusty winds during the day Tuesday. A red flag warning remains in effect this afternoon for southeast Alabama for long durations of relative humidity below 25 percent. A red flag warning is also now in effect in central and coastal Walton for relative humidity below 25 percent with 20-foot winds around 15 MPH and ERC values over 26, as well as in Washington, Bay, Leon, and Wakulla counties where relative humidity will be below 25 percent for 4 or more hours and ERC values will be above 37. A fire weather watch is in effect for tomorrow for all of these counties except Walton (due to lower wind speeds). Red flag conditions may be possible Thursday as well. By Friday, moisture will begin to return to the area before our next cold frontal passage early next week. .Hydrology... Rainfall amounts yesterday were generally below an inch across the area. However, a few locations from Washington County Florida into SW Georgia received closer to 2 inches. With river levels running quite low, any rises seen no area rivers will be minor.the next chance for rain will come on Sunday.
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&& .Preliminary Point Temps/PoPs...
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Tallahassee 49 20 57 23 67 / 0 0 0 0 0 Panama City 49 28 55 36 65 / 0 0 0 0 0 Dothan 45 22 54 30 64 / 0 0 0 0 0 Albany 46 21 55 26 64 / 0 0 0 0 0 Valdosta 48 21 55 25 64 / 0 0 0 0 0 Cross City 52 21 58 25 66 / 0 0 0 0 0 Apalachicola 50 27 55 34 65 / 0 0 0 0 0
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&& .TAE Watches/Warnings/Advisories...
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FL...Hard Freeze Warning from 11 PM EST /10 PM CST/ this evening to 9 AM EST /8 AM CST/ Wednesday for Calhoun-Central Walton- Coastal Bay-Coastal Dixie-Coastal Franklin-Coastal Gulf- Coastal Jefferson-Coastal Taylor-Coastal Wakulla-Gadsden- Holmes-Inland Bay-Inland Dixie-Inland Franklin-Inland Gulf- Inland Jefferson-Inland Taylor-Inland Wakulla-Inland Walton- Jackson-Lafayette-Leon-Liberty-Madison-South Walton- Washington. Red Flag Warning until 5 PM EST /4 PM CST/ this afternoon for Central Walton-Coastal Bay-Coastal Wakulla-Inland Bay- Inland Wakulla-Leon-South Walton-Washington. Fire Weather Watch Wednesday afternoon for Coastal Bay-Coastal Wakulla-Inland Bay-Inland Wakulla-Leon-Washington. GA...Hard Freeze Warning from 11 PM this evening to 9 AM EST Wednesday for Baker-Ben Hill-Berrien-Brooks-Calhoun-Clay- Colquitt-Cook-Decatur-Dougherty-Early-Grady-Irwin-Lanier- Lee-Lowndes-Miller-Mitchell-Quitman-Randolph-Seminole- Terrell-Thomas-Tift-Turner-Worth. AL...Hard Freeze Warning from 10 PM this evening to 8 AM CST Wednesday for Coffee-Dale-Geneva-Henry-Houston. Red Flag Warning until 4 PM CST this afternoon for Coffee-Dale- Geneva-Henry-Houston. Fire Weather Watch from Wednesday morning through Wednesday afternoon for Coffee-Dale-Geneva-Henry-Houston. GM...Small Craft Advisory until 10 AM EST this morning for Apalachee Bay-Coastal waters From Ochlockonee River to Apalachicola FL out to 20 NM-Coastal waters from Suwannee River to Keaton Beach FL out 20 NM-Coastal waters from Apalachicola to Destin FL out 20 NM. Small Craft Advisory until 9 AM EST Wednesday for Waters from Suwannee River to Apalachicola FL from 20 to 60 NM-Waters from Apalachicola to Destin FL from 20 to 60 NM.
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&& $$ NEAR TERM...FOURNIER SHORT TERM...WOOL LONG TERM...WOOL AVIATION...MOORE MARINE...WOOL FIRE WEATHER...MOORE HYDROLOGY...WOOL

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