Area Forecast Discussion
Issued by NWS Greer, SC

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS62 KGSP 260630 AFDGSP Area Forecast Discussion National Weather Service Greenville-Spartanburg SC 130 AM EST Sun Jan 26 2020 .SYNOPSIS... Seasonably cool and dry conditions are expected today. A couple weak surface lows will bring precipitation to the area Monday and again during the middle of the week. There is the potential for a fairly strong and moist weather system to affect the region by next weekend. && .NEAR TERM /THROUGH TODAY/... As of 115 AM: Expect shallow moisture in the west to northwest flow at low-levels to continue to impinge on the NC mountains overnight, producing cloudiness along the spine of the mountain chain. Isolated snow showers remain possible along the immediate border areas overnight, and also above 4000 feet, but little to no accumulation is expected in these spots. Otherwise, an upper low will continue to move northeast into New England while gradually weakening. Any lingering cold air advection will shut off today. This combined with weak downslope flow and insolation through thin, but increasing, cirrus will allow temperatures to rise to just above normal with highs mainly in the low to mid 50s. Mid to high clouds will begin to thicken across the forecast area late today ahead of the system approaching from the west. && .SHORT TERM /TONIGHT THROUGH TUESDAY/... As of 140 PM Saturday...the southern stream looks like it will remain relatively active through the first half of the week. A relatively weak system approaching the area Sunday night and moving overhead on Monday has our immediate attention. At first blush, it doesn`t appear to have much going for it. A lead short wave dampens out as it arrives Sunday night, followed by a mostly channeled vort on Monday and Monday night. Moisture is fairly deep ahead of the lead wave so there should be enough forcing and moisture to bring precip in from the west, but not until after mid-evening Sunday. The dampening wave will have trouble supporting precip east of the mtns early Monday, so precip chances barely make it to the chance range. It will take until the trailing wave arrives and we generate some weak instability over the Piedmont for us to get scattered precip east of the mtns Monday afternoon. Meanwhile, the combination of mid/upper forcing and developing W/NW flow will likely support shower activity on the west side of the mtns. The boundary layer will remain too warm for the precip to fall as anything other than rain in the valleys or east of the Blue Ridge. Not so above 4-5k ft. Fcst soundings suggest a snow level right around 4k feet through the event Sunday night and Monday, so all the precip would fall as snow at the highest elevations, with a few inches possible. Snow levels should fall in the wake of the system with some NW Flow snow continuing into early Tuesday morning. At this time, it doesn`t look like anything more than a potential high elevation advisory, so a Watch is not contemplated. Our eventual course of action might be dictated by the eventual snow level...if it falls, then the chances for an Advisory go up. Tuesday looks quiet and seasonal as high pressure builds in and NW flow weakens. Temps will be close to normal thru the period. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... As of 220 PM Saturday: The models continue to be somewhat lackluster in their depiction of a dampening short wave coming out of the srn Plains on Tuesday night and Wednesday, followed by a weak nrn stream wave passing to our north Wednesday night. So, our forecast remains somewhat non-committal with a blanket slight chance spreading across the region, which would be mostly liquid, and very little at that. High elevations would have a small chance at seeing some light snow. It doesn`t look like it will be anything more than a brief curiosity. Upper ridging Thursday and Thursday night should support dry high pressure moving past to the north, thus a quiet period with temps near normal. Confidence plummets from Thursday night onward. Model guidance has shown poor run-to-run consistency and relatively weak agreement between the various model solutions. For the time being, anyway, the 12Z runs show a consensus toward a Miller type-A low organizing over the nrn Gulf on Friday, with the low passing to our S/SE during the weekend. The GFS is about 24 hours faster than the ECMWF. However, neither has easy access to cold air. The pattern remains unblocked and the nrn stream progressive, so it does not appear to be a situation where high pressure would remain in a favorable spot for cold air supply. So, unless we can conjure up some cold air from somewhere, this system will look tantalizing, but may ultimately fail to deliver wintry precip outside the high elevations of the NC mtns. Best to manage expectations until we see better run-to-run consistency, but for now we will carry a chance of precip into Friday and Saturday...mostly rain with some high elevation snow...and near normal temps. && .AVIATION /07Z SUNDAY THROUGH THURSDAY/... VFR east of the mountains. A passing jet streak aloft will maintain SCT-BKN cirrus across much of the area early this morning, but mostly clear skies will be seen from daybreak onward. Moist northwest flow into the Appalachians continues, which will maintain low VFR to MVFR cigs along the Tennessee border. Early this morning these may briefly advect over KAVL. Ahead of an upper level disturbance, increasing clouds and lowering cigs will occur across the area, but cigs should remain VFR until after the end of the period at all sites. Outlook: Passing, weak disturbances may bring brief precipitation and restrictions on Monday and Wednesday, with VFR prevailing otherwise during the work week. Confidence Table... 06-12Z 12-18Z 18-24Z 00-06Z 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% 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 && .GSP WATCHES/WARNINGS/ADVISORIES... GA...None. NC...None. SC...None. && $$ SYNOPSIS...08 NEAR TERM...HG/65/08 SHORT TERM...PM LONG TERM...PM AVIATION...08

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.