Area Forecast Discussion
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089 FXUS62 KTAE 171119 AFDTAE AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 619 AM EST Mon Nov 17 2014 ...Slight Risk of Severe Storms Today... ...A Tornado Watch Is In Effect For Our Entire Warning Area... ...A Hard Freeze with Record Cold Temperatures Expected This Week... .Near Term [Through Today]...
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We have had a very active start this morning with several supercells forming out ahead of the main line, some of which have been tornadic. The tornado watch has been expanded to include our entire warning area. The western half of the watch will expire at 15Z, with the eastern half expiring at 19Z. Previous Near Term Discussion Below... Regional 04Z surface analysis showed an area of low pressure on the south-central border between Mississippi and Alabama, with a cold front extending southwestward from it across Mississippi and Louisiana and out over the northwestern Gulf of Mexico. A warm front extends eastward from the low, across southern Alabama and Georgia. Southerly flow out ahead of the cold front/south of the warm front has brought a return of warm, moist air to the area. With this return flow, we have already seen the lowest temperatures we will see for the night and surface dewpoints have already risen back into the 60s. Scattered convection in this warm sector will be seen overnight, with the main line of storms associated with this front moving west to east across the area after sunrise. The models continue to show a fairly tight gradient of SBCAPE along the coast, with 500-1000 J/kg likely along the coastline, with higher values offshore and lower values further inland. In addition to this available energy, we`ll also have a good amount of shear. GFS 0-1 km shear will be around 30-35 kts today ahead of the front with 0-6 km shear around 50-60 kts. The environment is favorable for the development of supercell thunderstorms. The main threat for severe weather today will be damaging straight-line winds, but an isolated tornado or two cannot be ruled out. SPC continues to show a slight risk for these severe storms, with the higher likelihood of these storms closer to the coastline with instability is higher. A tornado watch is in effect through 9 AM CST / 10 AM EST west of a line from Albany to Tallahassee.
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&& .Aviation...
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[Through 12Z Tuesday] Conditions will bounce up and down between MVFR and IFR ahead of an approaching cold front. Scattered convection may affect terminals in the morning ahead of the main line of thunderstorms ahead of the front, which will move west to east across the area between 13-20Z. MVFR cigs may linger for a few hours after the line has passed, but will improve to VFR by around 00Z. Winds will be gusty today, especially with the main line of storms and in the wake of the front, shifting from southerly to northwesterly with the frontal passage.
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&& .Prev Discussion [251 AM EST]...
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.Short Term [Tonight Through Wednesday]... The front should clear southeast of our zones early in the period taking any precipitation with it. An arctic air mass will then quickly make its way across the region. By daybreak, freezing temperatures will have made it as far southeast as VLD and inland portions of the FL Panhandle. Coffee County will actually flirt with hard freeze criteria, but should fall just shy of duration requirements. We upgraded all counties that were in the freeze watch to a freeze warning. Total freeze durations will range from about 2 hours along the southeast boundary of the warning to about 8 hours in Coffee County. When wind is factored in, wind chill readings will drop into the teens northwest of a line from Albany to Marianna to Destin. A wind chill advisory will be issued later today. Max temps will be quite cold by November standards. Look for mid 40s across Southeast AL tapering gradually upward to the lower 50s in Dixie County. The predicted high of 50 at TLH would tie it for the 4th coolest max temperature ever recorded within the first 20 days of November. This will set the stage for a widespread hard freeze Tuesday night and a hard freeze watch has been issued for the entire forecast area. Min temps by daybreak Wednesday will mainly be in the upper teens and lower 20s. This is exceptionally cold for November. In fact, the predicted low of 20 degrees at TLH would be the coldest temperature ever recorded that early in the season. Total freeze durations for this event will be as long as 14 hours well inland with even the Panhandle beaches getting a few hours of freezing temperatures. Highs Wednesday will range from the lower 50s north to the mid 50s south. .Long Term [Wednesday Night Through Monday]... We will see a moderating trend in temps through this period as the upper trough lifts away. In fact, we will actually see some upper ridging by Saturday. We should see one more freeze Wednesday night with min temps increase by a few degrees each night after that. Daytime highs will increase from the lower to mid 60s on Thursday to the lower 70s on Sunday. Surface high pressure will be in control as well keeping rain chances at a minimum through Saturday. However, by Saturday night and Sunday, another energetic system will be approaching from the west and initial indications are that there will be some potential for severe weather with this system as well. .Marine... Onshore winds will increase to advisory levels later this morning across the western waters. Winds will shift during the day with the passage of a strong cold front some strong storms could precede the front. Frequent gale-force gusts are expected in the offshore flow behind the front across our offshore marine legs from late this afternoon into Tuesday morning and a gale warning has been issued. Winds will not drop below advisory levels until Wednesday morning. High pressure will then build into the region keeping winds and seas below headline criteria from midday Wednesday through the end of the work week. .Fire Weather... A significantly colder, drier air mass will move in quickly behind today`s front. Relative humidity values will drop into the teens and twenties on Tuesday and Wednesday. Red flag conditions are likely. .Hydrology... Rainfall totals today will stay around 0.75-1.00 inches, which will cause minor rises on area rivers, but is not expected to cause flooding given how low our area rivers currently are.
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&& .Preliminary Point Temps/PoPs... Tallahassee 70 34 50 20 56 / 90 10 0 0 0 Panama City 69 33 50 29 54 / 100 10 0 0 0 Dothan 64 26 46 22 52 / 90 10 0 0 0 Albany 67 28 48 21 53 / 100 10 0 0 0 Valdosta 72 33 49 20 54 / 100 20 0 0 0 Cross City 74 38 52 21 56 / 90 40 0 0 0 Apalachicola 71 35 51 27 55 / 90 10 0 0 0 && .TAE Watches/Warnings/Advisories...
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FL...Hard Freeze Watch from Tuesday evening through Wednesday morning 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. Freeze Warning from Midnight tonight to 9 AM CST Tuesday for Calhoun-Central Walton-Holmes-Inland Bay-Inland Walton- Jackson-South Walton-Washington. High Rip Current Risk through late tonight for Coastal Bay- Coastal Gulf-South Walton. GA...Hard Freeze Watch from Tuesday evening through Wednesday morning 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. Freeze Warning from 1 AM to 10 AM EST Tuesday for Baker-Ben Hill- Calhoun-Clay-Decatur-Dougherty-Early-Irwin-Lee-Miller- Mitchell-Quitman-Randolph-Seminole-Terrell-Tift-Turner- Worth. AL...Hard Freeze Watch from Tuesday evening through Wednesday morning for Coffee-Dale-Geneva-Henry-Houston. Freeze Warning from Midnight tonight to 9 AM CST Tuesday for Coffee-Dale-Geneva-Henry-Houston. GM...Small Craft Advisory from 9 PM this evening to 1 PM EST Tuesday for Apalachee Bay-Coastal waters from Suwannee River to Keaton Beach FL out 20 NM. Small Craft Advisory until 4 PM EST this afternoon for Waters from Suwannee River to Apalachicola FL from 20 to 60 NM- Waters from Apalachicola to Destin FL from 20 to 60 NM. Small Craft Advisory from 10 AM Tuesday to 7 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. Gale Warning from 4 PM this afternoon to 10 AM EST Tuesday for Waters from Suwannee River to Apalachicola FL from 20 to 60 NM-Waters from Apalachicola to Destin FL from 20 to 60 NM. Small Craft Advisory until 1 PM EST Tuesday for Coastal waters From Ochlockonee River to Apalachicola FL out to 20 NM- Coastal waters from Apalachicola to Destin FL out 20 NM.
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&& $$ NEAR TERM...MOORE SHORT TERM...WOOL LONG TERM...WOOL AVIATION...MOORE MARINE...WOOL FIRE WEATHER...MOORE HYDROLOGY...MOORE

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