Area Forecast Discussion
Issued by NWS Greer, SC

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000 FXUS62 KGSP 080209 AFDGSP Area Forecast Discussion National Weather Service Greenville-Spartanburg SC 1009 PM EDT Fri May 7 2021 .SYNOPSIS... Drier high pressure will return over the weekend. Expect warmer temperatures on Sunday as the high moves over the Atlantic and a southerly flow of air returns. Another cold front will approach from the west Sunday night and then move slowly across the region Monday into early Tuesday. High pressure will set up by mid- week, but with a moist low pressure system returning from the west Wednesday night into Thursday. && .NEAR TERM /THROUGH SATURDAY/...
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As of 1000 PM: The cu filed has dissipated with the nocturnal cycle in full force to help stable the atmosphere. Post-frontal regime will be in store tonight with NW CAA filtering in to help temperatures drop well below-normal as mentioned below. The unseasonably deep and cold trough overtop the region will slide offshore into Saturday. But not before a secondary impulse rides the westerly flow through the region tonight, offering up another chance of showers and and high elevation snow mainly confined to the mountains near the TN border. Lows tonight will come in well below normal with lows in the 40s to near 50. A weak warm front is progged slowly gain momentum, mainly to the west of the area Saturday with the main impact being some mid-level clouds poking into the region from the west. Downsloping NW/W flow and a develop WAA regime during the day tomorrow will allow for the area to really dry. With more subsidence and a relatively dry airmass, the boundary layer will deepen Saturday afternoon and mix- out the lower levels of the atmosphere. Dew points should mix out into the 20s and 30s, which would drop RH values to near critical- levels, but a FDS is not warranted as of now since wind gusts won`t be as high as they were today. Rising heights and low level thicknesses will result in several degrees of warming over today with highs in the 60s across the mountains to 70s elsewhere.
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&& .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... As of 205 pm Friday: Heights will be on the rise early in the short term as a short wave ridge progresses across the TN and OH Valley, albeit in a dampening state in response to falling heights across the western Conus. Thus, the main story of the early part of the period will be the warming trend, as temps are forecast to return to above-normal levels, with widespread maxes in the 80s expected Sunday afternoon. As the dampening ridge progresses east of the area late Sunday/Sun night, a frontal zone associated with a region of height falls to our west will approach the forecast area, bringing precip chances to mainly the western half of the area by daybreak Monday, with PoPs ranging from low chance across the foothills and upper Savannah River Valley, to likely across extreme southwest NC/ the Smokies and vicinity. Frontal zone is forecast to progress steadily across the forecast area throughout Monday. In general, deep layer forcing is lacking. However, guidance depicts good Gulf moisture return in the warm sector, which allows for moderate destabilization across the Southeast Monday afternoon. As such, model convective qpf response increases throughout the day, and this appears good enough to advertise a likely PoP in most areas. Forecast wind profiles are more or less unidirectional, while the flow isn`t especially strong in the lowest 3 km or so. The combination of forecast shear/instability would therefore suggest a non-zero, but rather marginal threat for severe convection at this time. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... As of 220 pm Friday: Low amplitude troughing will become established across the East early in the medium range, allowing for a resumption of below-normal temps. In fact, Wed forecast max temps are a solid 10 degrees below normal. While global models depict a baroclinic zone hanging out south of the forecast area during mid-week, with generally dry conditions suggested for our forecast area, uncertainty regarding the timing of moisture return atop this baroclinic zone leaves us to advertise generally small pops Tue into early Wed. However, chances for moisture return will ramp up quickly late Wed into Wed night, and pops increase to likely across much of the forecast area by daybreak Thursday. Although much of the details will depend upon the track of any surface waves across the region, the overall pattern is suggestive of strong potential for at least in-situ cold air damming, and thus the risk for severe convection... or really any convection at all appears small. In fact, max temps will be forecast at 10-15 degrees below normal Thursday. PoPs will diminish and temps begin to warm again to end the period. && .AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
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At KCLT and elsewhere: VFR conditions are expected except KAVL where brief MVFR or low VFR cigs are possible at times from 03Z to 14Z. Can`t rule out a brief shower at KAVL during this time, but the highest chances will be confined to higher elevations especially near the TN border. Breezy W/NW winds should quickly drop off tonight, but will probably return at least briefly after 14Z. Only VFR level cu field is expected on Saturday, while remaining dry. Low end gusts could work back into the terminals during the afternoon/evening hours tomorrow. Outlook: Predominately VFR conditions are expected thru the weekend. The next shot at widespread restrictions may be with a Monday system. Confidence Table... 02-08Z 08-14Z 14-20Z 20-00Z KCLT High 100% High 100% High 100% High 100% KGSP High 100% High 100% High 100% High 100% KAVL High 100% High 100% High 100% High 100% KHKY High 100% High 100% High 100% High 100% KGMU High 100% High 100% High 100% High 100% KAND High 100% High 100% High 100% High 100% The percentage reflects the number of guidance members agreeing with the scheduled TAF issuance flight rule category. Complete hourly experimental aviation forecast consistency tables are available at the following link: www.weather.gov/gsp/aviation
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&& .GSP WATCHES/WARNINGS/ADVISORIES...
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GA...None. NC...None. SC...None.
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&& $$ SYNOPSIS...DEO NEAR TERM...CAC/Munroe SHORT TERM...JDL LONG TERM...JDL AVIATION...CAC

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