


Area Forecast Discussion
Issued by NWS Greer, SC
Issued by NWS Greer, SC
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187 FXUS62 KGSP 010136 AFDGSP Area Forecast Discussion National Weather Service Greenville-Spartanburg SC 936 PM EDT Mon Jun 30 2025 .SYNOPSIS... A typical summer pattern continues with seasonable temperatures and chances for afternoon and evening thunderstorms. A cold front approaches the area Tuesday with a chance for stronger thunderstorms. Behind the front, drier weather returns for the Independence Day holiday weekend. && .NEAR TERM /THROUGH TUESDAY/... As of 930 PM: Apparent convergence bands have been responsible for redevelopment of showers/storms since sunset along distinct axes from just west of Augusta to Forest City and also from just west of Columbia to Rock Hill to Salisbury. Thus heavy rain looks to move slowly across the Charlotte metro and we will be monitoring for heavy rain and possible stream rises in the urban area. CAMs basically are not resolving this convection so revised PoPs over the next few hrs based on current radar mosaic, allowing chances to linger longest in the current axes and also over the south-facing Blue Ridge Escarpment where southerly flow will continue and guidance is more consistent in depicting spotty redevelopment into the overnight. There may be more in the way of clouds overnight ahead of the approaching front but still expect mountain valley fog with patchy fog elsewhere, particularly where heavy rain fell late in the day or evening. Lows near normal mountains and a few degrees above normal elsewhere. The stagnant pattern finally begins breaking down Tuesday and a weak upper trough and surface cold front move into the area from the west. This will keep high PW values across the area and bring an uptick in bulk shear. The increased clouds and lower thickness values will help put highs a little below normal for the mountains and near normal elsewhere. This will keep instability slightly lower, but still reaching at least the moderate range. Deeper moisture is expected as well limiting DCAPE and sfc delta theta-e values. But given the increased forcing, overall severe thunderstorm potential is higher as some weak organization may develop. Isolated flood threat remains as well as storm coverage should be higher despite faster cell movement. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/... As of 100 PM Monday: An upper trough axis will cross the spine of the Appalachians Tuesday night and set up roughly along the East Coast Wednesday thru Thursday as the upper flow pattern amplifies. This should push a cold front thru the forecast area on Wednesday. Scattered diurnal convection is expected, with better coverage to our southeast. Temps will be near climo. The front pushes further southeast of the area Thursday, resulting in drier conditions. Only very isolated showers or storms expected, mainly in the mountains, as heights rise aloft and limit instability. Temps Thursday will be a category or so warmer with less cloud cover than Wednesday. Lows will be near climo. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... As of 130 PM Monday: Relative dry weather is expected for the Fourth of July holiday weekend (dry for early July). An upper ridge will slowly build in from the Midwest to the Ohio Valley and into the Mid-Atlantic. This will help suppress convection and keep mid-level lapse rates weak. An axis of sfc high pressure will extend from the Mid-Atlantic west to the Mid-MS valley, while a front stalls out over FL and the Gulf. Below-climo PoPs is in the forecast for Friday and Saturday. PoPs trend toward climo Sunday, but the latest guidance has trended drier. This is due to the uncertainty on a tropical low development along the stalled front in the eastern Gulf. The 12z GFS has come in more in line with the ECMWF on keeping any disturbance shunted south. Regardless of what happens in the Gulf, PoPs should begin to ramp up to more typical mid-summer levels, as a northern stream trough begins to dig into the Upper Midwest and the upper ridge shifts east. Temps will be close to or slightly above normal thru the period. && .AVIATION /02Z TUESDAY THROUGH SATURDAY/... At KCLT and elsewhere: Some well developed cumulus are still seen on satellite at issuance time which is worthy of low VFR mention in TAFs for the first couple of hours. Matched with light precip returns within 10-20 mi, included VCSH at KCLT. Can`t absolutely rule out development at the other sites in the first hr or two but chance too small to mention. Otherwise, light SW winds with dissipating cu by late evening and just FEW-SCT high altitude clouds overnight. Radiation fog/stratus likely in the mountain valleys with a fleeting chance at KAVL near daybreak, hence TEMPO. Confidence remains low. Winds pick up still from the SW late morning with diurnal cu developing in similar fashion to Monday. Approaching cold front however will provide better overall forcing. Thinking that diurnal SHRA/TSRA chances will develop similarly to the past couple of days, but with chance lingering a bit later into the evening based on timing of front. Multiple rounds are possible. VCTS for slightly earlier start possible at KAVL and VCSH continues to 06z at KCLT on the back end. Otherwise PROB30 for peak coverage/impact period. Outlook: Chance of afternoon and evening showers and thunderstorms again Wednesday. Drier air moving in Thursday may help inhibit convection into the weekend. Fog and/or low stratus possible each morning in the usual mountain valleys as well as near lakes and rivers. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...None. NC...None. SC...None. && $$ SYNOPSIS...ARK/CP NEAR TERM...RWH/Wimberley SHORT TERM...ARK LONG TERM...ARK AVIATION...Wimberley