Area Forecast Discussion
Issued by NWS

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
921 FXUS62 KTAE 140737 AFDTAE AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 337 AM EDT Mon Apr 14 2014 ...Strong to Severe Storms Possible From Late Tonight Through Midday Tuesday... .Near Term [Through Today]...
-- Changed Discussion --
Today we will transition out of an upper level ridging pattern as a rather amplified trough pushes into the eastern half of the country. A 06z surface analysis depicted a rather benign pattern locally, under the influence of high pressure which is centered off the Mid-Atlantic coastline. As the upper ridge moves east, so will the surface ridge, veering low-layer flow from the east to the south. As it does so, weak isentropic ascent will generate scattered showers up the spine of the Florida Peninsula, through the Suwannee Valley, and north into south-central Georgia. An isolated thunderstorm may be possible across Georgia late in the afternoon when the showers encounter a fairly unstable environment as steep lapse rates advect east through the Southeast. Otherwise a scattered CU field out ahead of the sea breeze fronts can be expected today, with a rather solid high cloud deck persisting all day long. High temperatures will be similar to yesterday, possibly a degree or so cooler with the plentiful upper level cloud cover. Convection associated with an approaching frontal system will likely hold off until later this evening across southeast Alabama and the eastern Florida Panhandle. .Short Term [Tonight Through Wednesday]... The long wave trough over the center of North America will shift eastward during this period with a potent short wave rotating through its base as it crosses the forecast area on Tuesday. The associated cold front will sweep across the area from northwest to southeast from 09-21z Tuesday. Showers and thunderstorms will precede the front. At this time, it appears a squall line will enter the area around 02-04z and bring a threat for damaging wind gusts. The hail threat will be primarily north of the region, but our northwestern zones could get some hail. There is also a non-zero tornado threat of tornadoes, particularly in any discrete cells out ahead of the main line and closer to the greater instability near the Gulf Coast. By sunrise, the main band of convection is expected to be over the FL Big Bend and South Central GA. There still appears to be sufficient shear and instability in place at that time for a marginal severe threat in these areas before 18z. Most convection will exit east of the area by sunset. An unseasonably cold airmass will arrive behind the cold front with highs on Tuesday struggling to reach 60 degrees over Coffee County AL Tuesday afternoon. South Central GA and the FL Big Bend will peak in the lower 70s. Strong cold advection Tuesday night will drive temperatures down into the 30s for all but our southeastern FL Big Bend counties and coastal areas. This is about 15 degrees below normal. It does not appear that any records are in jeopardy, but wind chill reading will drop to around 30 degrees give or take a few. That winter coat may have to come out of the closet one more time. Highs on Wednesday will rebound to the upper 60s north to mid 70s southeast. .Long Term [Wednesday Night Through Monday]... A gradual warming trend is expected for the end of the week and into next weekend. As for rain chances by the latter part of the period, the models have begun to diverge significantly once again, with the GFS still indicating the potential for a possible two- pronged rainfall event, while the ECMWF shows a split in the jet stream flow, which would allow one shortwave to pass to our north and another to pass to our south. This would leave most of the CWA protected with fair and seasonable conditions, but it is clearly too far in advance to buy solely into one of these solutions. Therefore, will plan on a compromised resultant for the end of the period, using our statistically verified blend of GFS/ECMWF/HPC guidance which has shown to be quite difficult to beat over the long haul.
-- End Changed Discussion --
&& .Aviation...
-- Changed Discussion --
[Through 06Z Tuesday] A patchy MVFR to IFR fog/ceiling mixture will be possible at ECP later this morning, though confidence is low due to the substantial coverage of high cloudiness. The only other restrictions through this afternoon could affect VLD late in the afternoon as showers and possibly isolated thunderstorms accompanied by low ceilings pass from south to north across the Suwannee Valley. Overnight a line of storms will move from west to east across the Tri-State region, likely bringing IFR (or lower) restrictions to terminals along and west of a line from ABY to TLH.
-- End Changed Discussion --
&& .Marine...
-- Changed Discussion --
Onshore winds will pick up to cautionary levels tonight ahead of a cold front. After frontal passage, offshore winds will quickly increase to small craft advisory levels for Tuesday and Tuesday night before veering to the east and dropping to cautionary levels from Wednesday into Friday morning.
-- End Changed Discussion --
&& .Fire Weather...
-- Changed Discussion --
Relative humidity levels will remain well above critical thresholds for the next couple of days as flow veers southerly ahead of an approaching frontal system that is expected to bring a decent amount of rainfall across the Tri-State region tonight through Tuesday. In it`s wake, the lowest relative humidities will be on Wednesday, but it is unclear whether durations or fuel moisture criteria will be met to warrant Red Flag conditions.
-- End Changed Discussion --
&& .Hydrology...
-- Changed Discussion --
The Choctawhatchee, Apalachicola, Ochlockonee, and Withlacoochee rivers all remain in at least minor flood stage as of this morning. With the exception of the Withlacoochee, all river flooding remains confined to north Florida. A frontal system will bring a widespread swath of 1 to 2 inch totals across primarily basins west of a line from Albany to Tallahassee. These amounts are represented well in several of the ensemble forecasts which results in a halt to lowering river levels. There is however the possibility of isolated higher rainfall amounts on the order of 3 to 5 inches. Should these amounts be realized over a basin, sharp increases should be expected. For real-time detailed river stage monitoring refer to the following page: http:/water.weather.gov/ahps2/index.php?wfo=tae
-- End Changed Discussion --
&& .Preliminary Point Temps/PoPs...
-- Changed Discussion --
Tallahassee 82 64 72 37 72 / 10 70 80 10 0 Panama City 74 61 66 42 70 / 30 80 70 10 0 Dothan 80 57 63 36 69 / 30 90 60 10 0 Albany 81 62 68 36 70 / 10 80 80 10 0 Valdosta 85 63 74 38 73 / 20 60 80 20 0 Cross City 83 65 75 42 75 / 10 40 70 20 10 Apalachicola 76 64 69 42 69 / 10 70 80 10 0
-- End Changed Discussion --
&& .TAE Watches/Warnings/Advisories... FL...None. GA...None. AL...None. GM...None. && $$ NEAR TERM...HARRIGAN SHORT TERM...WOOL LONG TERM...GOULD AVIATION...HARRIGAN MARINE...WOOL FIRE WEATHER...HARRIGAN HYDROLOGY...HARRIGAN

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.