Area Forecast Discussion
Issued by NWS Greer, SC
Issued by NWS Greer, SC
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914 FXUS62 KGSP 051452 AFDGSP Area Forecast Discussion National Weather Service Greenville-Spartanburg SC 1052 AM EDT Fri Jul 5 2024 .SYNOPSIS... Above normal temperatures will persist through the weekend. Meanwhile, a cold front moves in from the north and becomes stationary near the southern portion of the forecast area on Saturday. This front will increase the chance for thunderstorm activity outside the mountains through Sunday. More typical summertime thunderstorm development returns Monday and persists through next week. && .NEAR TERM /THROUGH TONIGHT/... As of 1030 AM Friday: Heating up expectedly fast this morning under lots of early July sunshine. 14z temperatures and dwpts pretty close to the going fcst so not expecting to make anything more than isolated upward ticks of the inherited MaxT. At this point, with the progged downward nudging of afternoon dwpts, the occurrence of apparent temperatures of 105 acrs a large enough area in any non heat advisory zones, i.e. the NC fthls, would be considered low probability with maybe just Polk/Rutherford Counties breaking containment. Small storms starting to fire near the Smokies, and expansion of deep convective activity acrs the NC and N GA mtns is likely into early afternoon. Deep convection is expected to drift east out of the mtns thereafter, with additional storms developing in the Piedmont late aftn thru the evening. It should be pretty unstable, with 2000-3000 J/kg of sbCAPE, and enough mid-level dry air for sfc- delta-theta-E values over 30 K. So a few strong downbursts will be possible, given the environment. There may be enough shear to limit pure microbursts, but storms may organize around outflows for some damaging wind gusts. Tonight, the cold front should push into the area, providing continued forcing for convection possibly into the overnight. So slight chc to low-end chc PoPs will linger, especially near the TN border. Plenty of cloud cover and elevated dewpts will result in temps a few degrees above normal, making for a muggy night. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... As of 115 AM Friday...Upper heights begin to fall Sat as a weak sfc bndry moves into the region. This front looks to stall just south of the FA and provide a focusing mechanism for widespread convection during the afternoon. The atmos remains quite moist during this time with abv normal PWATS and with weak column flow, the stage may be set for slow and/or back-building cells which could lead to flooding issues by the later afternoon. The severe risk is not great as mlvl LRs remain low-end and no sigfnt forcing aloft will be present, however, a few cells could pulse to severe levels producing large hail and damaging downburst winds. With dewpts remaining in the l70s across the srn zones, HI values may once again reach advisory levels as temps rise abv normal by a few degrees. On Sun, drier air will work in from the nw/ly mostly abv the sfc, but close enuf to vertically mix dewpts back to normal. The models have trended a little drier with sfc hipres attempting to ridge in from the NW, yet still expect areas east of the mtns to have the best chance of convec along a weakening yet existing sfc bndry. High temps return to more normal levels Sun while lows persist a few degrees abv normal each night. && .LONG TERM /MONDAY THROUGH THURSDAY/... As of 135 AM Friday...The ext range will see the return of a more normal summertime pattern. Broad subTrop ridging will dominate aloft and keep any major fronts north and west of the area, while a sfc Bermuda High remains in a favorable position to maintain good Atl/GOM moisture flux into the area each day. Soundings look real similar each afternoon with warm mlvls and skinny sbCAPE yielding arnd 1500 J/kg or less each afternoon. Triggering will remain low, however, some models show weakening vort energy traversing the ridge Mon afternoon. In any case, not anticipating any organized severe threat as the column flow remains weak thru the period. However, PWATS remain abv normal so the potential exists for slow-moving high- precip storms to create isol hydro issues. Storms should have no problem activating early on each afternoon as LCLs link up with LFCS rather quickly in the moist environment. Thus, storm coverage will likely become abv normal with the mtns zones receiving the highest PoPs. Max temps return to normal levels with no good indication of HI issues, while a moist atmos maintains mins a little abv normal. && .AVIATION /15Z FRIDAY THROUGH TUESDAY/... At KCLT and elsewhere: The main concern today will be convection timing and coverage. Guidance in decent agreement on activity firing across the mountains in the aftn, then slowly expanding/drifting east into the Piedmont late aftn thru this evening. Have TEMPO at KAVL and PROB30 groups elsewhere with timing of greatest chances. Overall, guidance has trended a little slower/later with the timing, focusing more on the evening hours for the KCLT area. Winds will be out of the SW, peaking during the aftn. Convection will wane late in the 06z TAF period, with plenty of lingering VFR-level cloudiness and light wind. MVFR to IFR stratus may develop overnight across the area from west to east, but confidence remains modest. Outlook: Diurnally-driven convection will continue each day thru the weekend and into early next week, leading to sct showers and thunderstorms and possible restrictions each afternoon/evening. Fog and/or low stratus may develop each morning, especially over areas that received rain the previous day. && .CLIMATE... RECORDS FOR 07-05 MAX TEMPERATURE MIN TEMPERATURE STATION HIGH LOW HIGH LOW ------- ---------- ---------- ---------- ---------- KAVL 96 1948 71 1976 70 2018 46 1967 1933 KCLT 100 2012 66 1892 77 1993 57 1967 1954 1881 KGSP 99 2012 70 1976 78 2016 58 1967 1933 1892 && .GSP WATCHES/WARNINGS/ADVISORIES... GA...Heat Advisory until 8 PM EDT this evening for GAZ018-026-028- 029. NC...Heat Advisory until 8 PM EDT this evening for NCZ036-037-056- 057-068>072-082. SC...Heat Advisory until 8 PM EDT this evening for SCZ008>014-019- 104>109. && $$ SYNOPSIS...SBK NEAR TERM...ARK/CSH SHORT TERM...SBK LONG TERM...SBK AVIATION...ARK CLIMATE...GSP