Area Forecast Discussion
Issued by NWS Greer, SC

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000 FXUS62 KGSP 021136 AFDGSP Area Forecast Discussion National Weather Service Greenville-Spartanburg SC 636 AM EST Tue Mar 2 2021 .SYNOPSIS... Dry high pressure will build over from the north today. Low pressure will develop near the Florida panhandle this evening along a stalled front and move to the South Carolina coast by daybreak Wednesday. This system will spread moisture northward into the region tonight, with some light wintry precipitation possible in the North Carolina mountains overnight. Dry high pressure will return Wednesday into Friday before a moist Gulf Coast low pressure system possibly affects the southeast Friday night into Saturday. && .NEAR TERM /THROUGH TONIGHT/...
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As of 615 am EST: Surface high pressure moving east across the central Appalachians today will permit cooler and drier air to spill southward into the region. Quite a bit of high clouds could persist, especially across the southern half of the area today, as a closed low pressure system over the OK/AR region sends cirrus downstream over a shallow ridge axis into our area. Will maintain max temperatures some 5 to 10 degrees below climatology as the dry conditions are countered by lingering high clouds and cooler thicknesses. The upstream 500 mb low/trough will move east through the lower MS River Valley this evening and approach the base of the southern Appalachians overnight. This will induce a surface wave along the stalled frontal boundary near the Florida panhandle, with the low center transitioning to the SC coastal waters toward daybreak Wednesday. Questions remain over how far north precipitation associated with these features will be able to work back into the area, with the greatest chances in southern/southeast sections. Precipitation coverage and intensity will be lowest where profiles are coldest - generally north of I-40. Given the drier and cooler profiles over the mountains, light snow is the currently favored precipitation type there for the overnight hours, especially at the higher elevations, although a light wintry mix is possible at times. There is slightly better potential for overlap between the deeper moisture and colder temperatures in the southern NC mountains. We will currently feature an inch or less of snow in these southern mountain locations, mainly along the higher ridges. Areas from Franklin to Waynesville, and especially along the higher ridges in between, will need to be monitored closely in case the moisture trends a bit farther north. For now, will keep accumulations sub- advisory and continue a mention in the HWO.
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&& .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... As of 115 AM Tuesday...Precip will likely linger during the early part of the short range as there is some potential for the upper trof axis to slow down and allow for weak mlvl deformation while a weak sfc low traverse up the Atl coast and brings in back-side moisture. Not anticipating much rain accum and any additional snow amts would be across the wrn NC mtns in developing upslope flow. Max temps will be tricky Wed with the models indicating winds oriented for good downslope warming adjacent to the BR escarpment. So, have the highest temps bisecting the middle of the FA from the SW to the NE. Weak hipres continues to build in Wed night and with good rad cooling expected, there could be a localized dense fg threat as noted in the latest soundings and supported to some degree by MOS output. A dry day is in store Thu with max temps reaching well abv normal, esp east of the mtns, as deep subs develops overhead and combines with a w/ly downslope warming component. With mostly clear skies and little wind, the overnight periods will see mins drop to normal levels or a little below each night. && .LONG TERM /FRIDAY THROUGH MONDAY/... As of 220 AM Tuesday...The op models continue to agree pretty well with the large scale pattern over the ext range. A strong ulvl ridge acrossthe Rockies will traverse east thru Monday, which will supoort stg Canadian hipres building south across the ern CONUS underneath a deeply dry subs zone. The GFS is somewhat of an outlier compared to the CMC/ECMCF solns in depicting a weak trailing sfc trof across the Apps as it/s parent sfc low gets surpresed south of the area Fri night into Sat. This scenario has been noted in the ECMWF a couple runs ago, so will give some credence to this possibility and have bumped up rain PoPS to low-end chance Fri night across NE GA and the wrn Upstate. Periods of -snsh and flurries are possbile across the higher elevations of the central and southern NC mtns into Sat. However, any snow accums would be very light to negligible as moisture looks to remain very shallow and transient. A reinforcing sfc high builds down the east coast Sat night and continues widespread dry conds into Mon. Afternoon RH values will likely drop into the l30s or less outside the mtns each afternoon and low-end fire-wx concerns may be had by the late weekend depending on any precip realized Fri night and Sat. Otherwise, it looks this may be a good period for prescribed burns by forestry officials. With winds remaing genrally n/ly to e/ly, yet insol remains high, max temps shud be held right arnd normal thru the period, while mins also persist arnd seasonal levels. && .AVIATION /12Z TUESDAY THROUGH SATURDAY/...
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At KCLT and elsewhere: Anticipate mainly cirrus ceilings for the first half of the TAF period. Winds will be some flavor of northerly this morning, toggling more southeasterly through the afternoon. Better moisture will return north of a developing Gulf Coast low center overnight, with the best precip chances across the Upstate sites for the overnight hours. Cigs should fall into the MVFR, or possibly IFR range, there overnight. The moisture will strike more of a glancing blow across the NC sites overnight into Wednesday morning, but with a RA/SN mix possible from KAVL to KHKY if the precip survives that far north as the low center transitions to the SC coastal waters. A window of mainly light rain is more likely at KCLT. Will keep the NC TAF sites with mainly lower end VFR cigs for now with any light precip. Winds will adjust back to NW at KAVL and NE at the foothill and Piedmont terminals tonight. Outlook: Dry and VFR conditions will return from the west on Wednesday and persist through Friday. Moisture could return with a Gulf Coast low pressure system toward the weekend. Confidence Table... 11-17Z 17-23Z 23-05Z 05-06Z 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% Low 58% 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... GA...None. NC...None. SC...None. && $$ SYNOPSIS...SBK NEAR TERM...HG SHORT TERM...SBK LONG TERM...SBK AVIATION...HG

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