Area Forecast Discussion
Issued by NWS Greer, SC

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858 FXUS62 KGSP 240605 AFDGSP Area Forecast Discussion National Weather Service Greenville-Spartanburg SC 205 AM EDT Fri May 24 2024 .SYNOPSIS...
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Temperatures will remain several degrees above normal each day through the holiday weekend. Daily chances for showers and thunderstorms. A cold front on Monday brings cooler and drier conditions for the middle of next week.
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&& .NEAR TERM /THROUGH TODAY/... As of 10:25 PM EDT Thursday: Widely sct showers with a few weak, embedded thunderstorms continue to linger over our fcst area late tonight. As we head into the overnight, this activity should con- tinue to diminish as any lingering sfc-based instability dwindles and the weak upper shortwave energy moves further east. Once the convection exits the area overnight, gradually clearing skies should permit some amount fog development. With dewpts remaining elevated thru the overnight and winds going light to calm across the area, it`s looking more likely that fog could become more widespread than previously anticipated. Low temps Friday morning should be very similar to Thursday and remain about 4 to 6 degrees above climatology. Otherwise, we will remain under broad/flat upper ridging thru the period. Weak, embedded upper shortwave energy is expected to translate over our fcst area again Friday afternoon/evening and will provide at least some amount of upper level support for convection. Fog should sct out fairly quickly tomorrow morning giving way to another partly cloudy day. Profiles will once again support some afternoon convection, with most of the near-term guidance producing about 1000 to 1500 J/kg of sbCAPE and roughly 20 to 30 kts of bulk shear. Consequently, some thunderstorms could become severe and produce strong downbursts and/or damaging hail. SPC currently has most of our CWA in a Marginal Risk Area for svr convection for Fri. Based on the latest fcst profiles, this still seems reasonable despite the fact that the latest CAMs continue to struggle with the timing and location of convective development thru the afternoon and evening. && .SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
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As of 215 AM Friday: Picking up Saturday with gradual strengthening of an area of high pressure over the Gulf and a weak ridge extending northward over the CWA. As the ridge progresses eastward, shortwaves traverse the Carolinas and up the chances for additional showers and thunderstorms. Guidance keeps a steady stream of moisture in the area through the forecast period and beyond, with instability remaining prevalent. Latest guidance does bring some questions as far as coverage on Saturday, especially outside the mountains. EURO is trending for a few more areas outside the mountains, but the GFS trends drier. Cannot rule out a few thunderstorms at this time. Sunday looks to dry out a bit as the upper ridge axis crosses over the CWA and suppresses rain chances. However, height rises does make Sunday the warmest day with low 90s popping up in most places east of the mtns. Meanwhile, an upper low forms over the southern plains and lifts NE, bringing a chance for a FROPA across the mountains Monday, increasing rain and TS chances once again. At this time, guidance has decent upper flow of 30-40kts and sufficient instability. Modeled soundings show steep sfc-3km lapse rates, but with a strong T/Td spread and inverted-V. Will continue to monitor, though it appears to be more typical TS with a frontal passage. Overall, hotter temps returning for most of the holiday weekend and TS chances each day.
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&& .LONG TERM /TUESDAY THROUGH THURSDAY/...
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As of 220 AM Friday: Continuing with Monday night onward, the pattern becomes generally more dry as far as the synoptic pattern goes. Any remaining FROPA should be weakened closer to Monday night and pinch off rain and thunderstorms chances by Tuesday. As the strong upper low lifts towards the Great Lakes, a strong ridge builds over the central CONUS, taking on an omega pattern toward the north. Meanwhile, high pressure amplifies zonally to the south and balances height rise/falls through at least Wednesday. Long range models show an upper trough dipping southward from the Great Lakes. Given how far out the model runs are, there is still much uncertainty as to how far south and if the trough reaches the CWA. GFS suggests a stronger pressure gradient and possible rain chances, while the EURO remains less enthusiastic and keeps the area dry. After Wednesday, the ridge axis from the central CONUS propagates eastward toward the CWA and shunts rain chances with strong subsidence aloft. Temperatures should remain close to climo through the period as well.
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&& .AVIATION /06Z FRIDAY THROUGH TUESDAY/...
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At KCLT and elsewhere: A low confidence forecast this morning because of much uncertainty with the timing, coverage, and location of convection over the next 24 hours. Most of the convection will probably be organized around outflow boundaries and waves aloft, reference the two area of showers and storms working their way eastbound early this morning. We will handle this with amends and TEMPO groups as appropriate, to handle the restrictions around the precip. It is possible the precip will lead to patches of MVFR to IFR ceiling/vis with stratus and fog through daybreak, but it should mix out quickly. Wind will be variable and light. For Friday, will go VFR prevailing, with a PROB30 for afternoon thunderstorms and associated restrictions. Wind should be W to NW. After the loss of daytime heating, we should have only debris cloudiness. Outlook: A unsettled pattern will linger thru the weekend and into early next week, allowing for diurnal shower and thunderstorm chances each day and fog development each night/morning.
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&& .GSP WATCHES/WARNINGS/ADVISORIES... GA...None. NC...None. SC...None. && $$ SYNOPSIS...CP NEAR TERM...JPT SHORT TERM...CP LONG TERM...CP AVIATION...PM