Area Forecast Discussion
Issued by NWS Columbia, SC

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564 FXUS62 KCAE 192342 AFDCAE Area Forecast Discussion National Weather Service Columbia SC 742 PM EDT Thu Sep 19 2024 .SYNOPSIS... Isolated to scattered showers and thunderstorms expected this afternoon, with highest coverage in the eastern Midlands. Moisture appears more limited on Friday as high pressure build south from New England over the weekend into early next week. Dry and warm conditions through Sunday, then more seasonable early to mid week. && .NEAR TERM /UNTIL 7 AM FRIDAY MORNING/...
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Key Message(s): - Patchy dense fog toward morning Area is on the back side of the east coast trof this evening with northwesterly flow aloft. While PWs are still above 1.5 inches, synoptic scale subsidence will temper any attempts at additional showers forming overnight, so other than a few stray showers in the evening hours in the eastern third of the CWA, conditions will be dry overnight. However, with the plentiful moisture still around, very light surface winds, and the aforementioned subsidence at lower levels, conditions are set up for patchy fog to develop late tonight, with a few areas potentially seeing dense fog by sunrise.
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&& .SHORT TERM /7 AM FRIDAY MORNING THROUGH SUNDAY/... Key Message(s): - A drying and warming trend into this weekend. A weak upper level trough slowly lifts offshore on Friday and is replaced by northwest flow aloft this weekend. Precipitable water levels range from 1.25 to 1.5 inches despite the increasing subsidence and drying aloft. The region is at the tail end of the pulse convection season, therefore an isolated diurnal shower or two cannot be ruled out given the low level moisture and shortwave troughs moving down the backside of the departing upper level trough. The best chance for an isolated shower is on Friday with lesser chances this weekend. Temperatures will warm with increasing H5 heights to 5 to 10 degrees above late September climatology. Any precipitation with the isolated showers should be less than one tenth of an inch. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... Key Message(s): - Warm and dry weather expected to start the fall season. The deterministic and probabilistic ensembles models depict above normal H5 heights building into the Southeast U.S. from the Gulf of Mexico into the middle of next week. This should lead to dry weather and above normal temperatures. The models diverge on solutions by next Wednesday with the handling of an upper level trough over the Ohio River Valley. There could a be a chance of showers Wednesday and Thursday. The models also differ on the timing and trajectory of a potential tropical system moving into the Gulf of Mexico at the end of the forecast period. && .AVIATION /00Z FRIDAY THROUGH TUESDAY/...
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VFR conditions expected for much of the period with restrictions from the pre-dawn hours through mid morning. Upper level low continues to move east of the terminals and offshore with weak high pressure ridging into the area. With sunset showers which had developed are quickly coming to an end along with the strato-cu and cu dissipating. Overnight expect some cirrus to continue drifting over the region with stratus and fog developing during the pre-dawn hours. With drier air moving into AGS/DNL expect MVFR to IFR restrictions mainly due to cigs with IFR to possibly LIFR at CAE/CUB/OGB where better moisture will reside. Restrictions will mix out shortly after sunrise with the remainder VFR as some diurnal cumulus develop from late morning through the evening. Winds through the period will be northeasterly at 6 knots or less. EXTENDED AVIATION OUTLOOK...No significant impacts to aviation expected through Tuesday.
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&& .CAE WATCHES/WARNINGS/ADVISORIES... SC...None. GA...None. && $$