Area Forecast Discussion
Issued by NWS Greer, SC

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571 FXUS62 KGSP 281742 AFDGSP Area Forecast Discussion National Weather Service Greenville-Spartanburg SC 142 PM EDT Tue May 28 2024 .SYNOPSIS...
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A cooler and drier air mass will gradually build into the region through the end of the week, with high pressure moving across the region at the start of the weekend. Once the high moves off to our east on Sunday, we should see a slow warm up with a return of the mainly afternoon and evening showers and thunderstorms.
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&& .NEAR TERM /THROUGH WEDNESDAY/...
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As of 130 PM: Synoptic cold front and sfc trough now along the Atlantic coast, with cyclonic upper flow over the eastern CONUS. Weak inversion aloft should preclude any deep convection this aftn, although shallow convective layer beneath that inversion will permit a healthy cu field across much of the area, particularly near the mountain spine where clouds may spill in from East TN. Ridging will strengthen over the CWA tonight into Wed as upper trough makes slight eastward progress. Continuing relatively dry westerly flow, combined with diurnal mixing this aftn lowering crossover temp, suggests minimal fog tonight despite fairly good radiational cooling conditions; min temps will end up 2-3 degrees below normal. Ridge should reinforce capping inversion and inhibit deep convection again Wed. A shortwave rotating thru the trough will however strengthen the low-level gradient; along with deeper mixing as a result of lower dewpoints that suggests slightly windier conditions Wed. Max temps however will trend down a couple degrees, returning to about normal.
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&& .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
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As of 130 PM EDT Tuesday: Broad cyclonic flow aloft will remain overhead through much of the short-term period as cP surface high shifts from the Upper Great Lakes region and sets up shop across the Mid-Atlantic/Carolinas by Friday. Cyclonic flow aloft will shift offshore later Friday as a steep upper ridge axis slowly builds in from the west. Needless to say, the forecast will be warm and very dry as dewpoints remain in the 40s and 50s across the CFWA. Enjoy this now as this could be one of the last stretch of actual Spring before we become entrenched with heat and high humidity for the coming Summer months. Temperatures will be slightly below-normal through the forecast period.
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&& .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... As of 237 AM Tuesday...Looks like we should get the first half of the weekend with nice weather as a mid/upper ridge builds in from the west, supporting high pressure, which keeps high temps a few degrees below normal and low temps nicely cool Friday night. However, the pattern is progressive and the model guidance is consistent with moving the ridge axis overhead late Saturday. Once that happens, weak sfc high pressure gets pushed off the Carolina coast and moisture return from the Gulf of Mexico will improve. Showers and thunderstorms could arrive as early as Saturday night as a lead short wave is shown to ride up the ridge from the west. Whether or not this takes the form of a dying MCS remains to be seen, but that is plausible. Sunday begins a more active period for us as we regain an air mass more favorable to diurnal convection. Much beyond that, confidence remains low as there is poor run-to-run consistency with how to handle the next mid/upper trof to the west. Previous runs had a large cut-off low and tonight`s runs bear little resemblance. Instead, we see a series of short waves moving along in a more low amplitude flow and a compact upper low somewhere not west of here. A common theme is that we stay unsettled with diurnally driven or enhanced convection, so a chance of precip will be kept for the early part of the week. Temps climb back to a few degrees above normal, while low temps have a more noticeable climb to something closer to five above normal by Tuesday night. && .AVIATION /18Z TUESDAY THROUGH SUNDAY/...
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At KCLT and elsewhere: VFR. Diurnal cu at 050-070 will be seen this afternoon but are expected to remain too shallow to support precip, beneath weak midlevel inversion. Winds prevailing in NW quadrant with weak trough east of the region, but with overall gradient weak some variability is expected. Low-end occasional gusts this aftn. Although good radiational cooling conditions will be in place, likely too dry tonight for fog/stratus. Approach of shortwave Wed should permit deeper mixing and slightly better gust potential, but precip chances still much too low to mention. This feature could also allow KCLT to back to near due W, perhaps even WSW, but not confident enough to advertise a switch this far out. Outlook: VFR conditions expected to remain as drier weather prevails through the end of the week.
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&& .GSP WATCHES/WARNINGS/ADVISORIES... GA...None. NC...None. SC...None. && $$ SYNOPSIS...DEO NEAR TERM...Wimberley SHORT TERM...CAC LONG TERM...PM AVIATION...Wimberley