


Area Forecast Discussion
Issued by NWS Columbia, SC
Issued by NWS Columbia, SC
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774 FXUS62 KCAE 311220 AFDCAE Area Forecast Discussion National Weather Service Columbia SC 820 AM EDT Mon Mar 31 2025 .SYNOPSIS... Widespread thunderstorms, with severe storms possible this afternoon ahead of a cold front which will cross the region by tonight. Well above normal temperatures expected for late week with possible record highs late week and next weekend. && .NEAR TERM /THROUGH TONIGHT/... Key Message(s): - Afternoon convection with severe storms possible - Primary threat is damaging winds but isolated tornadoes and hail also possible Regional radar currently shows a line of convection pushing through central WV and TN with multiple bowing segments and a history of damaging wind gusts. A few showers are also developing across the eastern Midlands and Coastal Plain due to weak isentropic lift. Aloft, an upper level trough continues to shift eastward across the middle of the country which will push a cold front through the area by tonight. Ahead of the front today, continued southerly low level flow around the western Atlantic surface high will provide continued warm and moist advection over the forecast area leading to air mass destabilization through the day. Morning stratus may delay or impact the initial destabilization but guidance suggests MLCAPE values will exceed 1000 J/kg during peak heating with modest but sufficient effective wind shear around 30-40 knots which should support the threat of severe weather. Latest HRRR runs consistently showing this initial convective line diminishing as it moves east of the mountains but leaving a residual outflow boundary somewhere across the northern Midlands. This could become a focus for enhanced helicity and a increased tornado threat when afternoon convection moves into the region. Hi-res guidance is in reasonable agreement developing convection across the Gulf Coast states after 12z which then tracks eastward through the day encountering an increasingly unstable high theta-e environment resulting in a line of strong convection moving through our area mid to late afternoon (18z-01z) with possible isolated discrete cells developing ahead of the line. Hi-res guidance also showing some updraft helicity tracks moving across the Midlands and CSRA with a more recent enhancement of them across the northern Midlands (likely associated with the forecast outflow boundary) which is a change from previous forecast thinking that the tornado threat would primarily be confined to the CSRA and southeast Midlands. So while there does not appear to be a significant tornado threat, with a more likely storm mode being cold pool dominated linear multicellular segments, the tornado threat does exist across the entire forecast area. As mentioned, damaging wind gusts are the primary threat of severe weather given the fairly unidirectional wind profile but large hail cannot be ruled out either. PWAT values continue to be high (over 200% of normal) and will support heavy rain potential but storm motion should be high enough to limit flash flood threat. Temperatures today should warm again well into the 70s with some lower 80s possible in the eastern Midlands, depending on how quickly the lower stratus can burn off. After the convection pushes east of the forecast area this evening lingering cloud cover will limit radiational cooling and expect some return of stratus due to abundant low level moisture in place until the cold front pushes through. Cold advection should commence behind the front late tonight and overnight lows expected to fall into the 50s ranging from the lower 50s west to upper 50s east. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... - A transient cool, dry airmass will on Tuesday will make way for a steady warm up and moisture return that starts Wednesday. Follow Monday`s cold front passage, Tuesday will be the coolest day for the forecast period as temps remain in the 70`s. With broad cold, dry advection and downsloping, PWAT`s will drop down below 0.5" and surface dew points will fall into the 40`s. As broad offshore high pressure and ridging develops into Wednesday, warming temps and moisture will return. Some upslope and isentropically forced showers are possible as we flip over to a warm advection regime thanks to that strong Bermuda high. So a few showers are expected mainly in the Upstate and western Midlands Wednesday. Otherwise, temps will push into the mid 80`s in most spots, 10-15 degrees above average. && .LONG TERM /THURSDAY THROUGH SUNDAY/... - Highly anomalous warmth expected with near record high temps Thursday through Sunday. The long term period will be dominated by deep mid-upper level ridging and an extremely strong offshore surface high. These will yield near or exceeding record high temps across much of the area starting Thursday and lasting through Sunday; the timing of when the next front actually clears the area next week is still uncertain. Regardless, high temps well into the 80`s or low 90`s are expected during this window, with a remarkable signal in the EC EFI and NAEFS for anomalous max and min temps. EC EFI shows consistent 0.9+ with SoT of over 1.0 for both max and min temps Friday and Saturday. NAEFS shows near record 500mb heights off the Atlantic coast with 99th percentile heights and temps throughout Friday and Saturday. So overall, guidance is flagging this period as one of the more anomalous temp patterns we have seen in awhile. Exactly when this ridging will clear out is a bit uncertain, but GEFS and ECE both push a strong front through the region sometime Sunday or Monday of next week, following by a notable cool-down into the extended range. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... IFR ceilings continue this morning before showers and thunderstorms this afternoon lead to possible restrictions. IFR stratus continues to be seen at all sites this morning with calm to light southwest winds being seen. Ceilings are expected to rise by 15z-16z as southwesterly winds increase to around 10-15 knots with gusts to 20-25 kts possible. After this, VFR conditions are expected into the early afternoon but model guidance continues to show a line of storms moving through the area ahead of a cold front during the afternoon hours with possible severe storms. I am maintaining the tempo for TSRA and enhanced wind gusts from 19-22z at all sites but OGB, where the timing is looking closer to 20-23z. Visibility and ceiling restrictions will be possible with the passing of this line as well. Behind the line, southwest winds lighten and with abundant moisture remaining in place before the cold fronts passing into Tuesday morning, another stratus deck is expected to form after 6-8z until the end of the current period with associated restrictions nearing IFR conditions again. EXTENDED AVIATION OUTLOOK...The cold front is expected to move through the area tonight with lingering possible restrictions into early Tuesday. Early morning low clouds continue to be possible Wednesday and Thursday morning. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...None. GA...None. && $$