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
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
287 FXUS62 KTAE 251532 AFDTAE AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 1032 AM EST Wed Feb 25 2015 .Near Term [Through Today]...
-- Changed Discussion --
Active weather is expected through tonight as a potent upper trough swings through with a moderately strong area of low pressure developing along the northern Gulf coast. Divergence aloft ahead of the upper system coupled with strong lift ahead of the surface low will lead to a large area of rain spreading over the forecast area during the afternoon. With the stationary frontal boundary nearly bisecting the forecast area, high temperatures will vary widely today, with highs ranging from the upper 40s northwest to the lower 60s in the southeastern Big Bend. As far as the threat of severe weather goes, there remains a non- zero risk, particularly near the coast. Shear will be very strong (even for our local cool season standards) thanks to very strong wind fields just above the surface with 850 mb winds in the 60-70 knot range this evening. Expected 0-1 km shear values are up to 50 knots across the area with some of the convection allowing models forecasting 50 knot environmental winds down as low as 1500 feet. The track of the low pressure will be particularly important to the severe risk as that will largely determine how much instability makes it inland from the coast. Currently, we expect the best chance of severe weather in a corridor stretching across Gulf, Liberty, Franklin, and Wakulla counties starting late this afternoon and lasting into the evening hours. It is in this area where there is the best model agreement on a narrow wedge of instability making it inland and overlapping with the very strong shear values. Damaging winds and a tornado or two are the main risks. Farther to the north, the degree of destabilization is highly uncertain, although a marginal risk may exist into southwest Georgia if the low tracks farther to the north. Regardless, there is some elevated instability present according to the BUFKIT forecast soundings, so isolated thunderstorms were included up into Georgia.
-- End Changed Discussion --
&& .Prev Discussion [250 AM EST]...
-- Changed Discussion --
.Short Term [Thursday through Friday]... Although rain will mostly end by the beginning of the period (12Z Thursday), clearing may not be absolute as model forecast soundings are in good agreement in showing a moist layer trapped just below the frontal inversion through much of Thursday. This may lead to more cloud cover and a cooler day than models are currently indicating. For now we trended things slightly in that direction, although more significant changes may be needed if models continue to show that boundary layer evolution. More substantial clearing is expected Thursday Night and Friday, although it should not continue to get colder. A 900-700mb anticyclone will begin to re-establish off the Southeast Atlantic coast, which should cause the air mass to begin to modify across the region. Temperatures will still be slightly below normal. .Long Term [Friday Night through Wednesday]... Most of the extended will feature slowly rising heights and return flow across the region. The increased moisture may bring some periods of low cloud cover and a slight chance of some rain showers, but the primary forcing mechanisms for rain chances will remain off to the north and west. The main trend in this time frame will be steadily rising temperatures. A few locations may crack the 80 degree mark by early next week, although the current forecast only reflects mid-upper 70s. .Aviation... [Through 12z Thursday] Unsettled conditions will prevail through the period as an area of low pressure moves along the Gulf coast, bringing widespread rain to the area and the possibility of thunderstorms and gusty winds to ECP and TLH by this afternoon into this evening. Ceilings will lower into the MVFR to IFR range. .Marine... There was some consideration given to possibly issuing a Gale Warning for most or all legs of the coastal waters. Model guidance is consistently indicating a narrow band of gale force gusts just in advance of the line of storms along the cold front. This is likely due to a very strong jet of low-level winds just above the surface. While we feel reasonably confident that gale force gusts will occur, we currently think the spatial and temporal extent will be limited to a scale of about 1-2hr or 30-50NM in advance of the convective line. That is also supported by model guidance. This falls somewhat short of the "frequent gust" requirement of the GL.W criteria. Therefore, a strongly worded Small Craft Advisory was issued instead with a supplementary bullet point in the product regarding the gust potential. This will be monitored today in case the area of gale force gusts becomes more expansive. .Fire Weather... There are no fire weather concerns expected for the next several days as afternoon relative humidities are expected to remain well above critical levels after the wetting rains today and tonight. .Hydrology... Widespread rainfall totals of 1-2 inches are expected today through tonight across the area with localized amounts in excess of 3 inches possible. These totals will cause rises along our area rivers and bring several sites along the Kinchafoonee Creek and the Choctawhatchee, Ochlockonee, Aucilla, and Upper Withlacoochee Rivers into action stage. The Withlacoochee River at Valdosta is likely to crest near minor flood stage by the end of the week and could reach a higher and earlier peak if rainfall totals end up being higher than currently forecast.
-- End Changed Discussion --
&& .Preliminary Point Temps/PoPs...
-- Changed Discussion --
Tallahassee 60 43 57 39 60 / 90 100 10 10 10 Panama City 59 44 54 40 57 / 100 90 10 10 10 Dothan 48 39 52 35 54 / 100 100 10 10 10 Albany 51 41 53 36 56 / 100 100 10 10 10 Valdosta 56 43 56 40 59 / 90 100 10 10 10 Cross City 66 53 61 43 63 / 40 90 40 10 10 Apalachicola 63 46 57 42 59 / 80 100 10 10 10
-- End Changed Discussion --
&& .TAE Watches/Warnings/Advisories...
-- Changed Discussion --
FL...None. GA...None. AL...None. GM...Small Craft Advisory until 3 AM EST Thursday 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.
-- End Changed Discussion --
&& $$ NEAR TERM...DVD SHORT TERM...LAMERS LONG TERM...LAMERS AVIATION...DVD MARINE...LAMERS FIRE WEATHER...DVD HYDROLOGY...DVD

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