Area Forecast Discussion
Issued by NWS Greer, SC

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000 FXUS62 KGSP 192054 AFDGSP Area Forecast Discussion National Weather Service Greenville-Spartanburg SC 454 PM EDT Sun May 19 2019 .SYNOPSIS... A few showers and thunderstorms are expected across the mountains this afternoon and evening. Thunderstorm coverage may increase Monday as a weak cold front crosses the forecast area. Following the front, a strong area of high pressure will build across the region resulting in well above normal temperatures with limited rainfall into the weekend. && .NEAR TERM /THROUGH MONDAY/...
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As of 450 PM EDT Sunday: This afternoon is evolving similar to the last couple days, though with temperatures a 2 or 3 degrees cooler due to weakening of ridge over the area. Upper trough is advancing well north of the area and will drag a weak trailing front through the region from the northwest late Monday morning through the afternoon. The other difference is the lack of convection ongoing at the moment. Much less convection overall and limited to the TN border of the northern mountains so far. Have updated PoP trends to show the lower overall trend and limiting location to the NC mountains. With front on Monday, coverage of showers is expected to increase with POPs reaching 30% over the mountains and some chance for showers in the foothills and piedmont areas as well. Moisture is still limited over the area, and upper dynamics are well to the north, so The CAPE/shear combination should keep things below severe levels today and on Monday, as confirmed by CAMs which have very weak updrafts in their forecast. Due to still somewhat widely scattered nature of convection on Monday, total rainfall amounts are not expected to be high, though those locations directly impacted by thunderstorms could receive useful rain amounts. Passage of the Monday front will be followed fairly quickly by renewed ridging and the beginning of a dry and unseasonally warm period.
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&& .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/... As of 125 PM Sunday: Upper level heights continue to rise over the short range before a pronounced h5 ridge axis forms and bisects the FA early Wed. Soundings indicate a negligible chance for precip Tue as deep layered subs increases and parcels only lift to arnd 4-5 kft with no identifiable LFC abv a stg llvl cap. So...will expect a warm dry day with max and min temps arnd 10 degrees abv normal. The llvl pattern begins to change Wed as a nrn sfc high shifts offshore and brings in a good amt of return moisture within a low BL. The atmos will be be too suppressed outside the mtns for anything more than shallow Cu. However...isol mech-lift showers and pulse mode tstms are possible by the afternoon as ridge-top convg enables thermals to reach an area of elevated weak instability. Another abv normal temp day in store Wed...but highs shud be closer to normal across the ne/rn zones as a ene/ly flow veers while a sfc wedge erodes thru the day. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... As of 220 PM Sunday: the extended fcst picks up at 00z on Thursday with persistent upper ridging still in place over the region. Over the next couple of days, the upper ridge is expected to amplify as deep upper trofing remains over the Western CONUS. As we move into the weekend, the long-range guidance has the ridge flattening a bit but not by very much. At the sfc, broad and transient high pressure will be moving off the Atlantic Coast as the period begins. As the high moves farther SE, we remain under a weakly forced and stagnant synoptic pattern thru day 7. As mentioned in previous discussions, this pattern will maintain well-above normal temps thru the period, with lower-to-mid 90s likely across the lower elevations and mid-to upper 80s across the higher elevations. At the same time, the atmosphere will remain suppressed and provide minimal chances for afternoon/evening showers and thunderstorms. The high terrain will see the best chances for convection during the period, however even over that area, PoPs are restricted to just slight chance. && .AVIATION /21Z SUNDAY THROUGH FRIDAY/...
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At KCLT and elsewhere: Generally VFR expected for the next 24 hours, except for some isolated showers or thunder showers over the mountains. Somewhat weak front is expected to reach KCLT by 21Z on Monday, and will bring the wind to a more westerly direction, and eventually northwesterly after 00Z. With front, chances for precipitation increase, especially in the higher terrain areas, and KHKY and KAVL have a PROB30 for this. Increased cloud cover is also expected on Monday as the front enters from the northwest, but should remain above VFR limits. Winds are fairly persistently southerly to southwesterly this afternoon with some gusts expected with afternoon mixing, and remain southerly through Monday morning, with KAVL and KHKY first seeing some veering late in the morning. Outlook: Mountain valley fog will be possible each morning through mid-week. Diurnal showers and thunderstorms possible Sunday and Monday, with reduced chances thereafter. Confidence Table... 21-03z 03-09Z 09-15Z 15-18Z KCLT High 100% High 100% Low 59% High 98% 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 and ensemble forecasts are available at the following link:
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&& .GSP WATCHES/WARNINGS/ADVISORIES... GA...None. NC...None. SC...None. && $$ SYNOPSIS...SBK NEAR TERM...RWH/WJM SHORT TERM...SBK LONG TERM...JPT AVIATION...WJM is the U.S. government's official web portal to all federal, state and local government web resources and services.