Area Forecast Discussion
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031 FXUS62 KTAE 150103 AFDTAE AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 903 PM EDT Mon Apr 14 2014 .Near Term [Through Tonight]...
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Current forecast package in decent shape this evening and only a few tweaks needed to account for mesoscale evolution of convection to the west and location of surface features. 00z mesoanalysis indicates mesolow becoming better organized with MCS evolving over far srn AL. This feature may tend to track enewd along and just south of surface outflow boundary from earlier convective complex which extends roughly from central GA swwd to the far wrn FL panhandle. 00z sounding from TLH was not overly impressive, however feed of moisture/instability will likely be a bit greater west of the river where modest instability is present. Possibility of isolated damaging winds and large hail could accompany this MCS and is reason SVR TSTM watch is now in effect for wrn half of CWA until 07z. In addition flash flooding remains a distinct possibility with heavy rainfall rates, especially if activity hangs up and trains along residual surface outflow. Flash flood watch therefore remains in effect.
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&& .Aviation...
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[Through 00Z Wednesday]...VFR conditions will persist early this evening, but IFR cigs will occur overnight as a low stratus deck moves inland from the Gulf. Thunderstorms will move across our region from west to east ahead of the cold front, and will affect all terminals between 04Z-15Z Tuesday. Storms could produce heavy rain, gusty winds, and frequent lightning with brief visibility reductions to LIFR. Ceilings and visibility will gradually improve from west to east Tuesday morning through the afternoon as the rain ends, with VFR conditions returning to all terminals by the end of the period. Winds will increase as the front moves through, with wind gusts potentially reaching 25-30 kt Tuesday afternoon across the region.
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&& .Prev Discussion [511 PM EDT]...
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.Short Term [Tuesday Through Wednesday night]... The main band of convection (with some strong to severe storms and locally heavy rainfall) with the approaching cold front will be ongoing across much of the CWA on Tuesday morning, before a stronger Sfc low develops and ejects to our NE and begins to rapidly sweep the cold front through the CWA during the afternoon. Given the expected fast movement of the pre-frontal squall line, the overall threat for flash flooding will be decreasing from west to east across the CWA, with the SE FL Big Bend anticipated to receive storm total rainfall on the order of 1 to 1.5" when all is said and done. While this is not expected to cause any areal or flash flooding in this region, riverine flooding along the Aucilla and Suwannee Rivers will remain a distinct possibility. After the cold front moves through, much colder and drier air will rush in from the northwest on Tuesday night. Despite plenty of numerical guidance which is indicating low temps possibly reaching the freezing mark or below across portions of the western interior, believe this is a very unlikely scenario given the saturated ground and elevated winds overnight. Nevertheless, even the raw model data is quite cold for this time of year, so used a blend of the raw GFS and SREF, which still results in enough cold air advection to produce a fairly large area of low temps in the mid to upper 30s, which is about 15 to 20 degrees below climatology! A sunny but cool and dry day is expected for Wednesday, with highs only reaching the mid to upper 60s in most areas, with a few lower 70s well to the SE. Wednesday night will still feature below normal temps with lows in the lower to mid 40s to the north and upper 40s to around 50 to the south. .Long Term [Thursday Through Monday]... With the first low pressure system long gone by the beginning of the extended period, we should at least experience a 2 day break in the unsettled weather on Wed. and Thu. with an initial shot of unseasonably cold air moderating back towards climo levels. By the end of the week and through next weekend, however, the fcst will once again become quite difficult as the conditions are leaning heavily towards yet another very unsettled period. While the details on timing, potential rainfall totals, and the possibility of any severe weather have been very inconsistent from run to run in both the GFS and ECMWF, the chances of another significant rainfall event during this time frame are clearly increasing. This is definitely not welcomed news for our area rivers and streams, many of which remain elevated from previous rainfall events, and will be primed yet again by the initial rainfall event early in this week. Furthermore, until a more significant change in the synoptic pattern becomes evident across the CONUS, these anomalous digging shortwaves and potential heavy rainfall producers will continue to threaten the SE U.S. .Marine... Onshore winds and seas will gradually increase to cautionary levels tonight as series of developing waves of low pressure to our west will move northeastward from central LA to a position well to the north of the marine area by Tuesday morning. The final and strongest surface low in this series will then push a strong cold front from west to east across the waters on Tuesday, resulting in quickly developing Small Craft Advisory conditions as winds shift from southwest to northwest. Then, strong northerly winds will linger through Wednesday morning before the Advisory level conditions slacken as the winds become northeasterly in the afternoon. However, this break in the adverse marine conditions is expected to be short lived, as moderate to strong easterly winds are expected to quickly return and then last throughout the remainder of the week. .Fire Weather... Widespread wetting rain is expected later tonight and into Tuesday morning. This should limit fire weather concerns over the next 24 hours and increase fuel moisture. A drier air mass is expected on Wednesday, but fuel moisture levels should continue to be high. .Hydrology... Rainfall forecasts for tonight and early Tuesday continue to point toward increased confidence in a localized convective band of heavy rain setting up from the FL panhandle up toward southwest GA. In the area where any band sets up, rainfall amounts could easily range from 2 to 4 inches with higher amounts likely. Convectively induced heavy rainfall in any given area could result in flash flooding, especially over urban locations, with the general area of concern north and west of a line from Apalachicola to Tallahassee to Valdosta. River basins more likely to be affected include parts of the lower Choctawhatchee, Chipola, Apalachicola, and Ochlockonee. Additional rainfall tonight and Tuesday will slow the falling trend on area rivers and lead to rises on some, particularly in smaller basins. This will result in longer lived flooding this week along some area rivers, but given the uncertainty on where localized heavy bands of rain set up, it`s difficult to say which rivers may see the most notable rises. For real-time detailed river stage monitoring refer to this page: http:/water.weather.gov/ahps2/index.php?wfo=tae
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&& .Preliminary Point Temps/PoPs... Tallahassee 65 71 39 70 47 / 90 90 10 0 10 Panama City 64 68 43 67 52 / 100 70 0 0 10 Dothan 59 64 36 66 43 / 100 80 0 0 10 Albany 64 65 36 66 43 / 100 90 0 0 10 Valdosta 65 68 40 69 45 / 40 90 10 0 10 Cross City 66 73 43 72 48 / 10 90 10 0 10 Apalachicola 66 69 45 66 55 / 60 80 10 0 10 && .TAE Watches/Warnings/Advisories...
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FL...Flash Flood Watch through Tuesday morning for Calhoun-Central Walton-Coastal Bay-Coastal Gulf-Gadsden-Holmes-Inland Bay- Inland Gulf-Inland Walton-Jackson-Leon-Liberty-South Walton- Washington. GA...Flash Flood Watch through Tuesday 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. AL...Flash Flood Watch through Tuesday morning for Coffee-Dale-Geneva- Henry-Houston. GM...Small Craft Advisory from 8 AM Tuesday to 2 PM EDT Wednesday 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-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...EVANS SHORT TERM...GOULD LONG TERM...GOULD AVIATION...EVANS MARINE...GOULD FIRE WEATHER...LAMERS HYDROLOGY...LAMERS/HOLLINGSWORTH

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