Area Forecast Discussion
Issued by NWS Columbia, SC

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000 FXUS62 KCAE 120032 AFDCAE Area Forecast Discussion National Weather Service Columbia SC 832 PM EDT Tue May 11 2021 .SYNOPSIS...
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High pressure ridging in from the north and moisture riding over a frontal boundary stalled to the south will produce wedge conditions across the region tonight into Thursday. Dry weather along with a warming trend is expected Friday through the weekend.
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&& .NEAR TERM /UNTIL 8 AM WEDNESDAY MORNING/...
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The evening meso-analysis indicated a stable airmass across the northern and central Midlands with lingering weak instability across the southern Midlands and CSRA. Across the south, lifted indices were down to -5C with cape values around 1000 J/kg. Convection crossing southern GA may move into the CSRA and southern Midlands this evening. Given Dcapes only around 500 J/kg, the severe weather threat is low. Increasing moisture and isentropic lift will spread rain across the area mainly after midnight. The cold air wedge will begin to take hold late tonight. Wednesday`s high temperature will likely be at midnight tonight with temperatures continuing to fall through the morning hours. By sunrise, temperatures should range from the lower 50s north to around 60 south.
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&& .SHORT TERM /8 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/... Wednesday and Wednesday night: Surface front will still be situated over the southern cwa early Wednesday. Shortwave will be moving into the region from the west early in the day, bringing widespread rainfall into the area. Some rainfall may be heavy at times into the early afternoon, then should lighten up as the shortwave moves east of the cwa. Bigger issue will be the strengthening surface wedge that will be pushing into the area from the north. Temperatures may actually slowly fall throughout the day as a much colder airmass moves into the area. Daytime highs in the middle 50s across the northern counties, with the upper 50s in the Midlands, and the lower 60s in the CSRA. These readings are well below normal. By Wednesday night, some drier air will attempt to move in across the northern Midlands, possibly bringing a brief period of dry conditions overnight. Isolated to scattered light rain may still remain possible over the southern counties. Overnight lows will be in the mid to upper 40s. Thursday and Thursday night: The surface wedge pattern is expected to remain across the region during the day Thursday, and this should keep temperatures well below normal once again, although possibly not quite as cool as Wednesday. There may be some breaks in the clouds over the northern cwa later in the day, which could allow temperatures to be warmer than the southern cwa. There will be isolated to scattered showers through the period on Thursday, although rainfall amounts will remain light. Late Thursday night, drier air will finally overspread the cwa, bringing an end to all the rainfall. Depending on if and when the wedge breaks late Thursday, highs on Thursday will reach into the mid 60s for most locations, while overnight lows Thursday night drop down into in the mid 40s to around 50. && .LONG TERM /FRIDAY THROUGH TUESDAY/... Cooler and drier conditions being indicated by many of the models through the weekend. Temperatures will remain below normal, with a slight trend towards normal late in the weekend. Then next chance for rainfall not expected until after the end of the longer term period. && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
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VFR conditions prevail at the moment, but restrictions are expected throughout the majority of this forecast period. Moisture is increasing across the area ahead of an approaching system from the west. As a result, we have had a few showers and thunderstorms pop up this afternoon. Orangeburg was the closest terminal, and the storm was a bit to their north. More showers/thunderstorms continue to develop across central GA, but confidence isn`t high enough in them being widespread enough to mention anything more than VCSH. Coverage will begin to increase from south to north later on this evening beginning in the 03z-05z timeframe. Around this time, MVFR cigs should develop as well. These will gradually push northward as the evening progresses and an approaching shortwave forces them to do so. These showers/thunderstorms will gradually push northwards and weaken as stability increases across the area. Rain and MVFR cigs should settle into all the TAF sites by 07z tonight. From there, widespread rain is expected for much of the day. There could be some heavier pockets, but general vis shouldn`t fall under 4SM for any long amount of time. IFR cigs are expected as a wedge develops with surface northeasterly flow and cooling temperatures. The onset of this should be between 07z at OGB and 09z at the Columbia terminals. These conditions should prevail through 18z until the rain begins to push east of the area. Thereafter, I expect a gradual improvement of conditions from IFR to MVFR. I may be too quick to lift out of IFR, but NBM probabilities really start to lower around 18z and beyond. Winds at the surface will be pretty strong out of the northeast tomorrow. There may even be some gusts that jump into the 15-18 knot range. EXTENDED AVIATION OUTLOOK...Flight restrictions possible through Friday morning. Conditions improve for the weekend with the arrival of dry air.
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&& .CAE WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. && $$

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