Area Forecast Discussion
Issued by NWS Greer, SC
Issued by NWS Greer, SC
481 FXUS62 KGSP 031805 AFDGSP Area Forecast Discussion National Weather Service Greenville-Spartanburg SC 205 PM EDT Sun Aug 3 2025 .SYNOPSIS... Cold air damming setup will keep temperatures well below normal through the first couple of days into the new workweek. A gradual warming trend is expected by the middle part of the week into the weekend. Shower and thunderstorm chances stick around each day throughout the week. && .NEAR TERM /THROUGH MONDAY/... As of 145 pm EDT Sunday: Sfc high pressure will remain nosed SWWD into the cwfa through Monday in CAD or CAD-like orientation. The moist but weak upglide flow atop the sfc based stable layer is progged to gradually increase as the 92-85h flow veers and increases. Considerable cloudiness will linger regionwide through tonight with varying degrees of light shower chances, especially along and near the upslope areas. With the SWWD push of lower sfc dwpts today, especially in the NC piedmont, minimum temperatures Monday morning are expected to be well into the lower 60s, although svrl locales are not too far away from those values attm. The sensible wx on Monday may wind up being not too terribly different than today featuring a SW to NE gradient with respect to the strength of the upglide flow forcing shower activity. Showers should again become numerous in the escarpment and SW cwfa while the NC piedmont remains just with a token probability. Conversely, with the potential for more insolation, lower 80s are in the forecast for the I-77 corridor while the upper Savannah valley may fall short of 75 for maximum temperatures. && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/... As of 120 PM EDT Sunday: An upper trough will shift over the MS Valley, while sharpening without much movement and pulling in better moisture across the CWA Monday night into Tuesday. This is thanks to a deepening upper anticyclone over the southwestern CONUS and another over western Atlantic. At the surface, an in-situ CAD will persist as a weak surface high continues to nose in from the northeast, only to be reinforced Monday night into Tuesday as a second Canadian High shifts over Atlantic Canada and New England. The SREF continues to support a LI index between 4-6, indicating support for higher static stability to help keep persistent CAD-like conditions with a steady northeasterly component at the surface. The aforementioned upper trough, however, will start to breakdown in between the two anticyclones by the latter half of the period, while deep layer WAA with southeast to southwesterly flow filters in atop the surface layer. This may help to keep the CAD dome intact through Wednesday, while better moisture transport and upglide help to increase PoPs throughout the forecast period. The GFS remains a dry outlier with keeping most of the QPF response closer to the wedge boundary south and west of the CWA, while the rest of the deterministic guidance produces good QPF response across the area Monday night through Wednesday. Current profiles indicate better mixing in the low-levels with inverted-v profiles and a LI index closer to 0 and below (-1 to -3) by Wednesday, which suggest that the CAD erosion process should begin by the end of the workweek near the start of the extended period. Temperatures will certainly continue the CAD trend with overnight lows Monday and Tuesday remaining a category or so below normal, while afternoon highs on Tuesday and Wednesday gradually rebound compared to the near-term, likely due to some scattering clouds as strong August solar heating reaches the surface at times. Afternoon highs remain 8-12 degrees below normal Tuesday and 5-10 on Wednesday. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... As of 200 PM EDT Sunday: The flow aloft and at the surface begins to make subtle change by the end of the workweek as a stalled frontal boundary remains draped south of the CWA and the surface high slowly slides over the northern Atlantic. A coastal low feature is evident in most of the latest guidance by Thursday and lifts north going into the weekend. This would essentially erode any CAD that`s left lingering, but overall confidence remains low on how the synoptic pattern fully evolves during the forecast period. A persistent cold pool likely remains intact, while true CAD erodes thanks to strong August solar heating and LI values lowering, inducing much lower static stability. Surface divergence will support CAD erosion as well if the coastal low gets going and lifts north over the Mid-Atlantic Coast as is depicted in some deterministic runs. The flow aloft will be fairly saturated as continued southerly flow filters in, while dry northeasterly flow advects in the surface layer. Temperatures gradually warm through the period, but remain slightly below normal as a residual cold pool tries to hold on with persistent northeasterly flow at the surface to go along with elevated PoPs. Soundings do support better insolation and boundary layer mixing by Thursday through the weekend, which likely is contributing to the warming trend as well. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... At KCLT...Outside of the small possibility of a passing shower this afternoon it looks like KCLT will be just far enough removed from the moist lift to keep cigs VFR. Winds will remain NE around 10 kts within damming high pressure. Quiet wx and VFR conditions are slated to continue into tonight and Monday morning with the progged drying within the 85-70h layer. Elsewhere acrs the FA, flight conditions remain and/or become more unsettled although not terribly impactful as we will deal with a mix of VFR/MVFR cigs into tonight along with the ongoing light shower chances lingering through Monday. Outlook: Relatively cool and damp conditions will linger into Monday, with better chances for showers. Although temperatures only gradually warm back up over the remainder of the week, precipitation chances trend toward a more typical summertime regime with chances mainly in the afternoons and early evenings by midweek. Periodic restrictions remain possible. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...None. NC...None. SC...None. && $$ SYNOPSIS...CAC NEAR TERM...CSH SHORT TERM...CAC LONG TERM...CAC AVIATION...CSH