Area Forecast Discussion
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369 FXUS62 KTAE 211039 AFDTAE AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 638 AM EDT Mon Jul 21 2014 .Near Term [Through Today]...
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Updated at 638 AM EDT- The 11 pm EDT regional surface analysis was complex, as a wavy, quasi-stationary front over the Southeast was rather ill-defined. It extended from a broad, weak low pressure system (1014 mb) in Southern MS, east-northeastward across Central AL and GA. There was also a subtle trough along the FL Panhandle Coast. Vapor imagery and upper air data showed ample moisture over our region, though not the kind of deep layer moisture (and tropical connection) that often results in widespread heavy rain for our region this time of year. A fairly potent, positive-tilted trough was translating southeastward over the Southeast, and extended from Central TN to the TX coast. A fairly large, poorly-organized MCS has developed along the FL Panhandle coast and adjacent coastal waters, and was moving east at 10 to 15 MPH. This MCS appeared to be weakening somewhat, but even if it does, more convection is likely to develop later this morning and afternoon. Our forecast follows our 5 am EDT ensemble of Convection Allowing Models (ECAM) closely, with PoPs ranging from 40 to 80% today. The highest PoP is along the FL Panhandle and North FL coasts. The large scale environment (with weak winds aloft and somewhat marginal lapse rates) doesn`t appear conducive for severe storms. .Short Term [Tonight Through Wednesday]... The early part of the week will feature an upper level low just west of our forecast area slowly retrograding westward to near New Orleans by Wednesday. The stalled surface front across the area will slowly lose its definition and mid-upper level ridging will temporarily build back in with slowly rising heights. Therefore the general trend should be slightly higher temperatures and lower PoPs on Wednesday as compared to Tuesday. For Tuesday, PWATs will remain around 1.9 inches (near normal) over the eastern half of the area, and enough forcing for ascent should exist to contribute to numerous showers and storms again in those areas. Slightly drier air in the western half of the area with PWATs closer to 1.7 inches (25th percentile) will likely lead to lower convective coverage. Therefore, we included likely PoPs (>55%) across the east with lower values west. .Long Term [Wednesday Night Through Monday]... The mid/upper level trough will persist across the local region through the extended period. The trough will be wedged between the Bermuda Ridge and strong ridging centered over the Desert Southwest. Temperatures along with rain chances are expected to be at or above climo each day.
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&& .Aviation...
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[Through 18Z Tuesday] SHRA/TSRA were already developing across the FL Panhandle. We expect TSRA/RA at KECP until late morning, at KTLH and KDHN late morning through early afternoon, and KVLD and KABY this afternoon. The rain will coincide with brief periods of low VIS/CIGS and gusty winds. Outside of the rain, VFR conditions will prevail. A return to just isolated TSRA and generally VFR conditions are expected this evening and overnight.
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&& .Marine... Slightly higher winds (10-15 knots) lingering into today should keep seas elevated around 2-3 feet, and significant wave heights in that range are still being observed at the offshore buoys. While this won`t rise to SCEC levels, it should still create choppy conditions for mariners. Given the possibility for lingering breezy winds and the active rip currents yesterday, our general outlook for today is for a continued high risk of rip currents in Walton, Bay, and Gulf counties as active rip channels from yesterday may continue to be activated. Overall, though, the trend in the forecast is for winds to gradually diminish along with wave heights. && .Fire Weather... Rain chances will be quite high this week, especially in FL today. Red Flag conditions are not expected this week. && .Hydrology... With such deep layer moisture, heavy rain rates are expected today. However, flash flood guidance is still quite high across most of our region, and we expect convective cells to propagate quickly enough to avoid excessive accumulations on a wide scale. The exception would be if these high rates were to occur for a significant amount of time over urban areas. The probability of this happening is not high enough for a Flash Flood Watch, and we will just have to monitor this as the day goes on. The Shoal River at Mossy Head is above bankfull stage and will continue to be monitored. All other rivers are also currently below flood stage. && .Preliminary Point Temps/PoPs... Tallahassee 87 71 92 72 93 / 50 30 60 30 50 Panama City 86 75 89 75 89 / 80 20 50 20 40 Dothan 87 72 91 72 93 / 40 20 50 30 40 Albany 88 71 92 72 93 / 40 40 60 40 40 Valdosta 87 70 91 71 95 / 60 50 60 50 50 Cross City 87 71 92 72 93 / 70 50 60 40 40 Apalachicola 86 74 88 74 89 / 70 30 50 20 40 && .TAE Watches/Warnings/Advisories... FL...High Rip Current Risk until 8 PM EDT /7 PM CDT/ early this evening for Coastal Bay-Coastal Gulf-South Walton. GA...None. AL...None. GM...None. && $$ NEAR TERM...FOURNIER SHORT TERM...LAMERS LONG TERM...BARRY AVIATION...FOURNIER MARINE...LAMERS FIRE WEATHER...FOURNIER HYDROLOGY...FOURNIER

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