Area Forecast Discussion
Issued by NWS Columbia, SC
Issued by NWS Columbia, SC
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031 FXUS62 KCAE 061813 AFDCAE Area Forecast Discussion National Weather Service Columbia SC 213 PM EDT Mon May 6 2024 .SYNOPSIS... Scattered showers and thunderstorms continue through the early this week as multiple disturbances move across the region. A lull in activity is anticipated for midweek, with increasing chances of showers and storms towards the end of the week. Expect generally above average temperatures through the latter half of the week before transitioning to near or slightly below average next weekend. && .NEAR TERM /THROUGH TONIGHT/... Upper trough over the Tennessee River Valley into GA/AL taking on a slight negative tilt. The main short wave trough over southeast Tennessee into north Ga appears stronger on water vapor than suggested by GFS/ECMWF. Several short waves are expected to trigger convection this afternoon and into the evening. At the moment, there is a weak short wave over the CSRA that is triggering convection from the Pee Dee southwest across the Midlands. This convection will push to the northeast. At the surface there is a ridge offshore, the air mass is quite moist, due to moderate 850mb southwest moisture transport. The precipitable water is around 1.50-1.70 inches. The air mass is becoming moderately unstable with ML CAPE around 1000 J/kg with some lingering CIN. Low level convergence appears weak. Behind the initial short wave over the CSRA, clearing is developing, and stronger instability is developing over GA. Think the air mass will become more unstable later this afternoon as a second stronger short wave approaches. This will lead to scattered to numerous showers and thunderstorms through the early evening, the shifting to the north as yet another short wave moves through near the NC/SC border after 06z. So pops diminishing from south to north as suggested by CAM models after Midnight. Model soundings show steep low to mid level lapse rates this afternoon with weak shear. The soundings were quite moist this morning but the latest models showing some mid level drying ahead of short wave. In fact, DCAPE is increasing in GA. Now believe this drier air aloft will move into the region, especially the west Midlands/CSRA and Piedmont and the severe threat is marginally elevated. Stronger lift in those areas too. So Main threat, a few storms may produce damaging wind and locally heavy rain possible with light winds/training. Temperatures currently in the mid 70s but expect some warming as clouds thin out. Highs should be on track with low to mid 80s. Persistence with overnight lows in the 60s. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... Tuesday and Tuesday night: A shortwave trough is forecast to continue progressing eastward and out of the forecast area in the morning hours. There could be a lingering shower or thunderstorm in the Pee Dee early on in the day, but should be quick to exit the region if there are any showers. Behind the shortwave, relatively flat ridging moves over the region, allowing temperatures to rise to above average for this time of year. A weak shortwave is forecast to move through the broader ridge during the afternoon, mainly to the north of the forecast area. With moisture expected to remain relatively high through the day (PWATs around 1.5"), a few showers or thunderstorms could develop, mainly for the northern portions of the forecast area. Other areas should remain dry for the day. Overnight lows should remain above average as well. Wednesday and Wednesday night: Another warm day is expected on Wednesday as the broad ridge remains over the region. However, a larger scale upper trough is forecast to begin moving toward the Southeast from the Upper Midwest. Another shortwave is forecast to slide through the area in between the ridge and trough, which could spark more showers and thunderstorms. A majority of the energy from this shortwave looks to stay north of the area, but some guidance extends the energy into our forecast area. Forecast soundings from multiple models do support the potential for strong thunderstorms, mainly north of I-20. The soundings near Columbia indicate a bit of a warm nose around 700 mb, which should hinder convection. As you go north toward the Charlotte area, this warm nose becomes less pronounced, which is why PoPs are a little higher there and the potential for stronger storms is greater there as well. && .LONG TERM /THURSDAY THROUGH MONDAY/... Thursday and Thursday night: The larger scale trough continues to move eastward while a developing surface low and associated cold front move towards the area on Thursday. Another shortwave is forecast to move through the region, allowing for more convective activity in the afternoon and evening hours. With the larger scale trough approaching, temperatures aloft begin to cool, which would lead to eroding that aforementioned warm nose around 700 mb. This would lead to a higher chance for severe weather. Confidence has increased a bit in this scenario as the various model guidance has come into better agreement. That said there still remains some timing and strength differences, which would affect the overall severe weather potential for the region. Friday through Monday: Another round of storms looks possible Friday morning as some guidance indicates an MCS moving through the Deep South will make its way into the Southeast during the morning hours. There remains plenty of uncertainty with this scenario, so confidence is on the lower side as of now (~20%). After that and a cold front pass, more tranquil weather is forecast for the weekend into early next week. && .AVIATION /17Z MONDAY THROUGH FRIDAY/... Scattered showers and thunderstorms with brief restrictions at times through the early evening. MVFR Stratus/strato-cumulus possible late tonight. The air mass remains moist and unstable. At the moment, a weak mid level trough is moving through the area with light showers near the CAE/CUB/OGB terminals. Ceilings remain MVFR near the CAE terminal but expect improving conditions as the trough moves to the northeast. Outside of convection this afternoon expect broken VFR cumulus. Scattered thunderstorms are developing over north GA. These showers will move to the east and into the area late this afternoon and evening. Locally heavy rain possible so visibility likely reduced at times. The convection will slowly diminish during the evening, MVFR ceilings expected to develop overnight. The guidance favors stratus over fog with a strong low-level jet, mainly after 09z. Winds light, favoring south direction shifting to southwest. EXTENDED AVIATION OUTLOOK...Morning fog/stratus less likely on Wednesday with drier air over the region. The extended will be active, with mainly diurnal convection each day. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...None. GA...None. && $$