Area Forecast Discussion
Issued by NWS Greer, SC
Issued by NWS Greer, SC
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071 FXUS62 KGSP 152324 AFDGSP Area Forecast Discussion National Weather Service Greenville-Spartanburg SC 724 PM EDT Wed May 15 2024 .SYNOPSIS... Brief high pressure brings a mainly dry day on Thursday. Showers and scattered thunderstorms return Friday and continue into the weekend. Isolated afternoon and evening showers and thunderstorms are expected early next week. && .NEAR TERM /THROUGH THURSDAY/... 600 PM Update...Convective activity is slowly exiting the FA as an occluded low pushes to the southeast. Another line of showers will move across the NC mtns and north of I-40 over the next few hours but the airmass has destabilized to preclude much if any stg/svr threat this evening. Will begin paring back the SVR Watch from the west. As of 210 pm EDT Wednesday: The low level flow turns NW in the wake of departing trough. Some shower activity could linger into the overnight near the TN/NC border, warranting small PoPs in those areas through around Sunrise. Much less active convective weather is expected on Thu, as lower theta-E air filters in on NW flow, which will combine with a weak subsidence inversion to yield very most destabilization. There`s enough of a signal to support small PoPs for diurnal convection (primarily SHRA) across portions of the mountains during the afternoon. Max temps Thu will be a few degrees above climo. && .SHORT TERM /THURSDAY NIGHT THROUGH SUNDAY/... As of 200 PM EDT Wednesday: Dry conditions are expected Thursday night into early Friday morning thanks to upper ridging and sfc high pressure. Ridging pushes east throughout Friday morning as an upper low approaches out of the west. The upper low and its associated sfc low will track over the Southeast throughout the weekend, but some differences remain between the latest global model guidance sources regarding both the timing and strength of the low. Both the GFS and Canadian have the low lingering over the area on Sunday while the ECMWF has the system pushing offshore. Nonetheless, went with likely to categorical PoPs Friday afternoon/evening through early Saturday evening. Capped PoPs to chance Saturday night into Sunday as confidence is lower regarding if the low will stall over the region. Models continue to diverge regarding the amount of instability and shear available through the weekend, so confidence on the severe wx potential continues to remain low. The Day 3 SPC Severe Wx Outlook has the entire forecast area in a "General Thunder" Risk for Friday. However, strong to severe storms cannot be ruled out as global model guidance agrees that there will be decent deep shear associated with the area of low pressure through the weekend. There is higher confidence regarding the heavy rainfall/flooding threat throughout the weekend as PWATs are expected to climb near/above 90th percentile Friday afternoon through late Sunday. With wet antecedent conditions already in place, additional rainfall this weekend will allow hydro concerns to gradually ramp up. Lows will remain ~5-10 degrees above climo through the short term. Highs on Friday will be near climo to a few degrees above climo, becoming a few degrees below climo on Saturday. Highs on Sunday may return to near climo to a few degrees above climo if convection does not linger over the area. && .LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/... As of 230 PM EDT Wednesday: The ECMWF has the upper low pushing farther east into the western Atlantic Sunday evening into Monday while the GFS and Canadian have the low lingering over the eastern Carolinas during this timeframe. Thus, maintained chance PoPs across the northern zones through Monday. Upper ridging as well as sfc high pressure will build into the region Tuesday into Tuesday night leading to drier conditions. A cold front will approach out of the west towards the end of the forecast period, allowing convective chances to increase again from west to east. Both highs and lows through the period should end up a few to several degrees above climo. && .AVIATION /00Z THURSDAY THROUGH MONDAY/... At KCLT and elsewhere: A round of showers with a few embedded thunderstorms possible will traverse the NC areas this evening into the overnight. However, confidence is too low for any mention outside of VCSH at KHKY this evening. Otherwise, expect lowering VSBY to MVFR/IFR overnight at KAVL, KHKY, and KCLT. Developing low CIGs will also drop to low MVFR at KHKY/KCLT with high IFR possible at KAVL near daybreak. VFR conds return all sites aft 14z as winds remain weak and align ne/ly at KCLT to sw/ly elsewhere outside the mtns. KAVL will see winds setup nw/ly in channeled up-valley flow. Outlook: Convection active weather and associated flight restrictions return Friday, likely continuing through the weekend. Late night/early morning restrictions in low stratus and/or fog will also be possible. Drier weather is expected to return early in the next work week. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...None. NC...None. SC...None. && $$ SYNOPSIS...DEO NEAR TERM...JDL/SBK SHORT TERM...AR LONG TERM...AR AVIATION...SBK