Area Forecast Discussion
Issued by NWS Columbia, SC

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524 FXUS62 KCAE 190630 AFDCAE Area Forecast Discussion National Weather Service Columbia SC 230 AM EDT Thu Sep 19 2024 .SYNOPSIS...
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Showers and thunderstorms will be possible today, favored in the eastern Midlands. Moisture is expected to decrease Friday. High pressure will build into the area from New England over the weekend into early next week with dry and seasonable temperatures expected.
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&& .NEAR TERM /THROUGH TONIGHT/...
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Key Message(s): - Isolated to scattered showers and thunderstorms today The upper low will open up into a trough as it shifts eastward today. The axis of the trough will move offshore with drier air moving into the region through light N winds. Despite lower PWAT values than the previous day, atmospheric moisture remains relatively high in the eastern Midlands and Lowcountry with PWAT values from 1.6 to 1.7 inches. As convection develops in the afternoon, aided by shortwave energy rounding the base of the trough, development will be favored in the eastern Midlands. Drier air to the west will work to inhibit showers. Overall, the direr airmass will keep showers and thunderstorms isolated to widely scattered. Convection will diminish in the evening with loss of heating, although a weak shortwave could support an isolated, lingering shower into the overnight period. Mean sbCAPE values from the HREF are lower than 750 J/kg suggesting instability may be too limited for any severe threat. Highs will be in the low to mid 80s with lows overnight in the mid 60s.
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&& .SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
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Key Message(s): - Drier weather for Friday. - Seasonable temperatures. Friday and Friday night...Low-level moisture remains high through the day especially in the east. Precipitable water only decreases slightly. There appears to be a weak cold front/moisture boundary moving south from eastern North Carolina in the afternoon. Latest GFS/Nam suggest a few showers may develop in the east again as another short wave moves through upper trough, but appears more focused in the Coastal Plain potentially aided by sea breeze convergence. The NBM pops are quite low and mean CAPE lower than Thursday. Any convection should be isolated. Temperatures a little warmer than Thursday.
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&& .LONG TERM /SATURDAY THROUGH WEDNESDAY/... Key Message(s): -Drier into early next week with warming trend over the weekend The ensembles continue to be in good agreement. Upper trough off the east coast with upper ridge over the southern Plains building east but flattening with time. Surface high ridging down the Eastern Seaboard. Low-level moisture remains high, high level moisture may increase by early Monday as the ridge flattens. Ensemble qpf probabilities > 0.1 inch only 10-20 % Sunday/Monday. NBM pops very low at this time so will continue dry forecast. && .AVIATION /07Z THURSDAY THROUGH MONDAY/...
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Lingering low-level moisture over the region will promote patchy low clouds and fog over the terminals this morning. Given the patchy nature of the cloud decks it`s difficult to determine how prolonged any IFR or possibly LIFR conditions would last. With some drier air working into the area, fog could develop as clouds break up but would be localized. It is shaping up to be a messy forecast through the morning with low confidence in restrictions and their duration. Any possible restrictions would begin mixing out after sunrise but MVFR conditions could persist into the mid to late morning before all sites return to VFR. Winds will generally be light and out of the north. Convective coverage today should be more limited than the previous day, with highest rain chances in the eastern Midlands near OGB. At this point, confidence is not high enough to include in the TAFs but showers and thunderstorms will be possible again. Any convection will diminish during the evening hours. Drier air working into the region should reduce the chances of stratus like we`ve seen the previous nights. But shallow moisture lingering over the area could support patchy fog around sunrise. Extended Aviation Outlook...Drier air over the region will limit the chance of restrictions through the weekend before moisture begins to increase early next week.
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&& .CAE WATCHES/WARNINGS/ADVISORIES... SC...None. GA...None. && $$