Area Forecast Discussion
Issued by NWS Greer, SC
Issued by NWS Greer, SC
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742 FXUS62 KGSP 061914 AFDGSP Area Forecast Discussion National Weather Service Greenville-Spartanburg SC 314 PM EDT Mon May 6 2024 .SYNOPSIS... A summerlike weather pattern remains through mid week with mainly afternoon and early evening showers and thunderstorms. Temperatures will be well above normal Tuesday through Thursday. Showers and thunderstorms will be more numerous ahead of a strong cold front which will cross our region Thursday night and Friday. Expect drier and cooler weather for the weekend. && .NEAR TERM /THROUGH TUESDAY/... As of 2:45 PM EDT Monday: Widely sct showers continue to make their way east across our area with a line of more discrete thunderstorms moving off the Escarpment and into the Piedmont and Upstate. This activity will likely weaken over the next few hrs as it moves further eastward, but additional strong storms are possible. Otherwise, additional convection will likely develop over our higher terrain this afternoon. However, the environment is expected to be less hospitable to stronger convection outside the mtns owing to more cloud cover earlier today and relatively modest instability. While shear para- meters are improved compared to the last few days, with deep layer shear of 25 to 30 kts (as opposed to < 20 kts the past couple of days), it likely won`t be enough to allow for anything more than an isolated svr storm threat, with the upper Savannah River Valley the most likely area to see a stray downburst and/or large hail. As flow turns NW aloft this evening, CAM guidance continues to suggest additional waves of sct showers and thunderstorms moving over western NC from eastern TN thru at least the late evening hours, so PoPs remain elevated in the 40 to 60% range during that time, while steadily diminishing elsewhere. Low temps early Tuesday will be roughly 10 degrees above climatology again. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/... As of 215 PM EDT Monday: A flat upper ridge will be in place across the area Wednesday with weak short waves rippling through the flow and across the area. A stronger short wave crosses the area early Thursday as an upper low moves into the Great Lakes. At the surface, a weak east/west oriented front stalls over the area Wednesday, with a cold front moving in from the west on Thursday. The air mass becomes very unstable Wednesday with moderate shear and mid level dry air leading to increased DCAPE and sfc delta Theta-E values. Coverage will be higher across the mountains, but severe storms will be possible at any location across the area given these parameters. Moisture increases on Thursday with less mid level dry air, DCAPE, and sfc delta Theta-E values. Instability also falls, but could remain in the moderate range while shear increases, approaching strong territory. Convective coverage still favors the mountains, but at least likely PoP will be featured across the area. Severe storms will again be possible, but overall chance is more uncertain. Highs Wednesday will push 90 degrees outside of the mountains, and mid to upper 80s in the valleys then fall a few degrees Thursday. Lows will be well above normal as well. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... As of 240 PM EDT Monday: The Great Lakes low opens into a trough which moves into the area Friday. A series of short waves keeps the general troughiness over the eastern CONUS through the end of the period. With the trough moving in on Friday, cyclogenesis takes place near the Carolina coast along the cold front that moves through on Thursday. Guidance keeps going back and forth on the location of the front and cyclogenesis, along with any lingering moisture and resulting precip. Have continued the trend of chance PoP for now given the uncertainty. A series of weak clipper-like low pressure centers of frontal systems move near or over the area through the rest of the period. This leads to isolated to possibly low end scattered showers for the mountains each day with dry conditions elsewhere. Temps fall to a few degrees below normal by Saturday, then rise back to near normal through the end of the period. && .AVIATION /19Z MONDAY THROUGH SATURDAY/... At KCLT and elsewhere: Another challenging fcst all-around for the terminals. Still expect mostly VFR conditions this afternoon and evening (outside of any showers and/or thunderstorms). We`ve seen a lull in shower activity since late this morning, however another round of sct convection is expected to move thru our area later this aftn and into the evening. This is mostly handled with VCSH and TEMPOs for TSRA at KCLT, KHKY, and KAVL. Per the latest CAM runs, the convective coverage looks more sparse for the Upstate terminals, so I just have VCSH with PROB30s for TSRA. Activity could linger well into the overnight and early morning across our area, but thinking it will be mostly showers after about 06z overnight and most likely impact KAVL. Visby and cig restrictions return to the area just before daybreak on Tuesday, with predominately MVFR visby and IFR cigs expected at most sites. Expect visby to improve and cigs to sct out by roughly 14z tomorrow with VFR for the rest of the taf period. Outlook: Moist profiles will combine with a weak/stalled front thru the mid-week, resulting in a period of active, mainly diurnal convec- tive weather each day. There is potential for restrictions associated with widespread fog and/or low clouds each morning. A cold front moves in later in the week with continued chances of diurnal convection. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...None. NC...None. SC...None. && $$ SYNOPSIS...DEO NEAR TERM...JPT SHORT TERM...RWH LONG TERM...RWH AVIATION...JPT