Area Forecast Discussion
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182 FXUS62 KTAE 270846 AFDTAE AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 446 AM EDT Sun Jul 27 2014 ...Dangerous Heat Indices Possible Today and Monday... ...Strong to Severe Storms Possible Monday Afternoon and Evening... .Aviation...
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[Through 12z Monday] Some low ceilings and patchy fog with MVFR to IFR conditions have developed this morning with a very soupy airmass in place. Conditions will improve rapidly to VFR after sunrise. Although an isolated thunderstorm is possible this afternoon, the chances for convection are well below average for this time of year with mid-level dry air in place and appear too low for any mention in the TAFs at this time.
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&& .Prev Discussion [356 AM EDT]...
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.Near Term [Today]... The main issue for today will be the heat. Both the CAM ensemble and MOS guidance have very low PoPs across the area today. Quite a bit of mid-level dry air is expected to put the kibosh on most of the afternoon convection with only a 20 PoP across the area. As a result, high temperatures will soar into the mid to upper 90s across most of the area with an isolated 100 degree reading possible. Dewpoints are expected to remain elevated this afternoon with low to mid 70s across most of the area. This will bring heat indices up to the 108 degree threshold needed for a heat advisory across a large portion of the area, we issued a heat advisory for most of the area. .Short Term [Tonight through Tuesday]... A deepening upper trough over the eastern half of the country will push an unusually strong deep summer cold front south into the forecast area on Monday. Ahead of the front, a very hot and humid airmass will be in place, with temperatures rising into the upper 90s Monday afternoon. Coupled with dewpoints in the mid 70s, expect to see heat index values exceed 105 degrees over a large portion of the area, with values as high as 110 degrees possible in Florida. Another heat advisory may be needed for Monday afternoon. As the front approaches the northern CWA border Monday afternoon, expect to see a swath of southward moving thunderstorms develop. With such a hot and juicy low-level airmass, expect to see CAPE values approach 4000 j/kg Monday afternoon ahead of the front. When coupled with a modest increase in mid-level northwesterly flow, expect to see a few of these storms reach severe limits, with damaging straight-line winds and large hail being the primary threats. With the aid of the front, the line of convection will likely remain active through Monday evening as it crosses the FL/GA line. The front will push to near a Valdosta to Panama City line by Tuesday morning, likely slowing its southward progress through the day. A much drier airmass will push in behind the front, with dewpoints dropping well into the 60s. Temperatures will be somewhat cooler as well, with highs ranging from around 90 degrees along the northern border, to lower to mid 90s along the coast. Showers and thunderstorms will continue south of the front, across the central and eastern Big Bend. .Long Term [Tuesday Night Through Sunday]... Model guidance continues to be in excellent agreement in the amplification of the Eastern CONUS trough through the long term period. While there are some slight differences on timing and magnitude of the cooler and drier air behind this frontal boundary, there is good agreement now that the front will clear to the south. Dry conditions should be in place across the region from Tuesday evening into Thursday. This interval will also feature some cool overnight lows, possibly dipping into the lower 60s in the colder spots across Southern Alabama. Even in the Florida Big Bend, temperatures Wednesday and Thursday mornings should drop into the upper 60s or just a bit cooler. Records for this period at Tallahassee are as follows: July 30 - 67 (1927) July 31 - 63 (1896) Aug 1 - 64 (1993) By Thursday afternoon, moisture will begin to increase once again across the forecast area as another upper disturbance within the main upper trough moves into the forecast area. Unsettled conditions look to return Friday and into next weekend with rain chances increasing considerably. While overnight lows will return to climatological norms for early August, daytime temperatures will still be below normal due to plenty of convective activity. .Marine... The pressure gradient between the subtropical ridge to the south and an approaching cold front to the north will tighten over the next two days, leading to a modest increase in westerly winds across the coastal waters. Winds will reach exercise caution levels at times through early Tuesday. Winds will then slowly diminish and become offshore through the middle of the week. .Fire Weather... Red flag conditions are not expected over the next several days, although high dispersion values are expected this afternoon across the inland Florida big bend and across most of the area away from the coast on Monday. .Hydrology... The Shoal River at Mossy Head has reached bank full stage but is not forecast to reach flood stage. All other area rivers are below bank full stage. Thunderstorms could bring locally heavy rainfall the next few days but widespread impacts are not expected.
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&& .Preliminary Point Temps/PoPs... Tallahassee 97 78 96 75 94 / 20 10 40 40 30 Panama City 90 80 92 78 91 / 20 10 40 40 20 Dothan 97 76 97 72 91 / 20 10 50 40 10 Albany 99 77 96 72 91 / 20 10 50 40 10 Valdosta 100 76 96 73 93 / 20 10 40 40 30 Cross City 93 76 94 76 93 / 20 10 30 30 50 Apalachicola 91 79 91 79 90 / 20 10 30 30 40 && .TAE Watches/Warnings/Advisories... FL...Heat Advisory from Noon EDT /11 AM CDT/ today to 7 PM EDT /6 PM CDT/ this evening for Calhoun-Central Walton-Coastal Bay- Coastal Franklin-Coastal Gulf-Coastal Jefferson-Coastal Taylor-Coastal Wakulla-Gadsden-Holmes-Inland Bay-Inland Franklin-Inland Gulf-Inland Jefferson-Inland Taylor-Inland Wakulla-Inland Walton-Jackson-Lafayette-Leon-Liberty- Madison-South Walton-Washington. GA...Heat Advisory from Noon today to 7 PM EDT this evening 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...Heat Advisory from 11 AM this morning to 6 PM CDT this evening for Coffee-Dale-Geneva-Henry-Houston. GM...None. && $$ NEAR TERM...DVD SHORT TERM...CAMP LONG TERM...GODSEY AVIATION...DVD MARINE...CAMP FIRE WEATHER...DVD HYDROLOGY...WESTON is the U.S. government's official web portal to all federal, state and local government web resources and services.