Area Forecast Discussion
Issued by NWS Greer, SC

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000 FXUS62 KGSP 241855 AFDGSP Area Forecast Discussion National Weather Service Greenville-Spartanburg SC 255 PM EDT Tue May 24 2022 .SYNOPSIS...
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Cool high pressure over New England will ridge down into our area through Wednesday. Low pressure over northern Texas will strengthen as it moves northeast toward the Great Lakes with a cold front approaching our region from the west. The coverage of showers and storms will increase Wednesday night through Thursday night ahead of the approaching cold front. The front crosses our area on Friday with dry high pressure moving into our region for the weekend and early next week.
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&& .NEAR TERM /THROUGH WEDNESDAY/...
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As of 2:30pm EDT Tuesday: Surface low responsible in part for severe weather yesterday is now well east of the area, leaving behind complex, though relatively low impact weather for the next 24 hours. Aloft, a modest shortwave in advance of the next synoptic trough swings northeastward tonight and is expected to give some showers this afternoon and tonight. At the surface, winds are light, but become more northeasterly this afternoon behind the surface low as a cold-air damming episode commences with a wedge front pushing across the entire area tonight. Some surface CAPE is analyzed from observations early this afternoon, with northeasterly CAD flow eliminating CAPE behind the wedge front. Showers are expected later this afternoon and evening as upper shortwave comes into play, but convection will be commencing as CAPE is in continual decline as front advances. This will create a somewhat narrow time and area for thunder from around 10pm to midnight, mostly over the western mountains southward. Currently, radar is clear, with showers expected to develop from southwest to northeast after 5pm. Areal average rainfall amounts through Wednesday morning will be light at a few tenths of an inch, though some isolated areas will receive more and many areas and areas in the eastern half of the CWA won`t get any rain in this period. Clouds have become scattered to broken with ceilings rising from low morning values. CAD will bring overcast and low ceilings by morning, along with northeast winds of 5 to 10 kts throughout the day on Wednesday. High temperatures will also be subdued tomorrow due to CAD/clouds, and reduced later today over northeast parts of the CWA that are already seeing northeast flow. None of the usual model blends reduced temperatures enough behind the wedge front, and made more manual adjustments to forecast temperatures than usual.
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&& .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
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As of 115 PM EDT Tuesday: An active pattern will return for the short term period of the forecast. A mid level ridge will be in place along the Southeast coast through the period, while a trough/possible closed low moves from the southern plains across the Ohio and Tennessee Valleys. At the surface, a cold front will move across the area on Friday. Expect areas of showers and thunderstorms each period. While much of the rain will be beneficial after the recent dry spell, locally heavy areas of rain may develop especially in the upslope areas of the southern Appalachians. Model instability and wind profiles also suggest that there will be some risk of severe thunderstorms from Thursday afternoon through early Friday.
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&& .LONG TERM /SATURDAY THROUGH MONDAY/...
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As of 115 PM EDT Tuesday: The system impacting the short term period will have moved off the coast by the weekend, with conditions drying out as a result. Mid level ridging will develop across the region with with strengthening of this feature indicated by early next week over the Ohio Valley. This scenario would lead to warmer temperatures early next week, with highs potentially climbing into the lower 90s in the Piedmont on Tuesday.
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&& .AVIATION /19Z TUESDAY THROUGH SUNDAY/...
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At KCLT and elsewhere: Northeast winds are becoming established in the wake of surface low that crossed the area last night. This will begin a period of cold-air damming with lowered CIGS expected at all TAF sites tonight and Wednesday. Winds Wednesday will be northeasterly around 5 to 10 kts and gustless. Currently, Ceilings of 1 to 3 kft have mostly scattered. Forecast soundings have CIGS in decline after dark this evening, reaching IFR levels by daybreak. Some weak shortwaves in advance of next trough may support some scattered showers this afternoon and tonight, mostly southwest of the KCLT and KHKY areas. Surface-based instability is marginal, and is wiped-out as wedge boundary advances from the northeast, resulting in little temporal overlap between rain and CAPE. Most likely areas for any thunder are KAVL to KAND for a few hours this evening. Outlook: Persistent moisture and cold air damming will keep precipitation and restrictions in the picture Wednesday into Thursday. Another cold front will arrive from the west late week. Nocturnal fog/stratus will be possible as well, especially where rain has recently fallen.
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&& .GSP WATCHES/WARNINGS/ADVISORIES... GA...None. NC...None. SC...None. && $$ SYNOPSIS...DEO NEAR TERM...WJM SHORT TERM...SCW LONG TERM...SCW AVIATION...WJM

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