Area Forecast Discussion
Issued by NWS Columbia, SC
Issued by NWS Columbia, SC
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509 FXUS62 KCAE 101810 AFDCAE Area Forecast Discussion National Weather Service Columbia SC 210 PM EDT Fri May 10 2024 .SYNOPSIS... Scattered showers and thunderstorms are possible again today as a cold front approaches and moves through the area today. High pressure then moves in for the weekend, bringing dry weather. The high moves offshore Monday and increasing moisture supports showers and thunderstorms returning for next week. && .NEAR TERM /THROUGH TONIGHT/... 10/15Z analysis places a surface low in the upstate with frontal boundaries extending northeast and southwest. Mainly scattered to broken high clouds across the region in wake of a significant MCS departing offshore to our southeast. Additional convection continues across the FL Panhandle. Temperatures across the Midlands and CSRA have risen into the mid and upper 70s with dewpoints in the mid and upper 60s ahead of the approaching front. While things are quiet at the moment, an approaching shortwave will enhance dynamics and generate showers and thunderstorms. A few showers have already initiated along the frontal boundary across the upstate. Latest CAM solutions including the last several HRRR runs and the WoFs are consistently depicting a line of storms forming particularly from the northeast CWA southwest through the Columbia area and pushing east. There is less confidence that another line will follow it, but in general areas northeast of Columbia look to be the most favorable for strong to severe storms. Conditions ahead of the front are expected to support at least a slight risk for severe thunderstorms, including large hail. The overall tornado threat appears to be low. Daytime heating combined with plenty of moisture will generate SBCAPE of 1500-2000 J/kg along with 40-60 kts of 0-6km bulk shear. Area soundings also depict ample CAPE in the hail growth zone and strong unidirectional shear. A severe thunderstorm watch is now in effect for portions of the CWA through 9 PM this evening. With the frontal passage this evening, skies are expected to clear quickly with winds becoming northwesterly. As such, dewpoints should fall through the 50s into the upper 40s in some locations and PW values drop below 1". Cold air advection will usher in cooler lows than we have seen as of late, generally in the 50s. Winds will remain somewhat elevated overnight though, so it appears any fog threat will be minimal. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... We finally made it! A much deserved break in the weather is expected this weekend as troughing, upper level convergence, and surface high pressure settle into the region. Guidance is in wonderful agreement in the forecast for Saturday and Sunday. Partly cloudy skies are expected on Saturday as a reinforcing shortwave dives through the Mid-Atlantic, with highs in the upper 70s. Lows will be in the 50s under clear skies Saturday night. Sunday should be a bit warmer with some downslope flow expected as high pressure shifts through the area. Highs should be in the 80s with lows in the upper 50s. && .LONG TERM /MONDAY THROUGH FRIDAY/... Fairly high confidence in the pattern that is expected to unfold next week. A progressive and meridional pattern is shown by LREF members by Monday and this should take us through the end of next week. Slow, lowish amplitude upper level trough is expected to be centered across the central Plains by Monday morning, with a ridge axis shifting across our FA through the day. Surface high pressure should still be in place but is expected to shift offshore by Monday night, with moisture and isentropic lift increasing through the day. Rain is likely by Monday night, with each group of ensembles in the LREF showing ~70-80% of members with rain chances by Monday night. Surface low should slowly push eastward on Tuesday, settling over the OH Valley. Strong westerly and southwesterly flow is shown by both operational models and LREF members. While operational models are unsure about convective potential, the overall synoptic setup is one that tends to favor at least thunderstorms across the FA. LREF members generally show decent probabilities (25-40%) of sufficient CAPE and shear to support potential strong storms. So we`ll need to keep a close eye on model trends over the next couple of days. Rain chances look to peak Tuesday evening, with the trough axis shifting the best lift and surface low to our east on Wednesday. The break looks short, though, as another shortwave is expected to dig into the south-central Plains. A ridge axis will likely settle in over the region by Wed/Thur, with significant uncertainty regarding the pattern thereafter emerging. The shortwave trough that digs into the southern plains looks like it could be significant, but timing and amplitude issues abound amongst LREF members and operational models. For now, will keep the NBM as is given the significant uncertainty in the long term. Temps should be seasonal or slightly below normal in this period given the repeated shots of rain and potential cloud coverage. Highs will likely be in the upper 70s to mid 80s with lows in the 60s. && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/... Expect a period of VFR conditions this afternoon. A line of showers and thunderstorms is then expected to develop and may cause some restrictions at the terminals this afternoon and early this evening. Mainly high clouds remain across the region this afternoon with continued thinning. Another round of scattered showers and storms are forecast to move through the region during the 18z-00z timeframe. Storms to the north will progress southeast this afternoon. Most of this activity looks to remain northeast of AGS and DNL, but have included VCTS in case development is slightly further southwest. Otherwise, the threat is covered at the terminals with TEMPO groups and there is potential for gusty winds in excess of 30 kts and brief CIG/VSBY restrictions. Thereafter into tonight, drier air and clear skies return along with VFR conditions. Breezy west to southwest winds 10-15 kts with gusts to 25 kts expected through about 11/00z before shifting to northwest. Speeds remain around 4-7 kts overnight into Friday morning. EXTENDED AVIATION OUTLOOK...No restrictions late tonight through this weekend. Showers and thunderstorms are possible Monday and Tuesday along with associated restrictions. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...None. GA...None. && $$