Area Forecast Discussion
Issued by NWS Columbia, SC
Issued by NWS Columbia, SC
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482 FXUS62 KCAE 241443 AFDCAE Area Forecast Discussion National Weather Service Columbia SC 1043 AM EDT Fri May 24 2024 .SYNOPSIS... A frontal boundary will approach the region Friday and is expected to stall near the area resulting in chances of showers and thunderstorms through the weekend. Another more organized system is expected to be crossing the eastern US Monday and Tuesday with additional chances for thunderstorms. Drier weather is expected to return Wednesday. && .NEAR TERM /THROUGH TONIGHT/... A moist airmass remains in place today with satellite derived estimates around 1.6 inches and dew points in the upper 60s currently. HREF indicating a high probability (70 to 80 percent) of PWATs remaining above 1.5 inches throughout the course of today, with probs a bit higher in the CSRA. Temperatures once again expected to be a few degrees above average, around 90F, which should lead to destabilization into this afternoon. Forcing may be a bit limited as recent model runs have trended a bit less defined with a shortwave moving into the area, or at the very least, timing is difficult to pin down. The entire area remains in a marginal risk for severe weather today with moderately high probability of sbCAPE exceeding 1000 J/kg, although there is still decent amount of spread in model guidance as to the degree of destabilization with some models indicating strong destabilization across the area. Deep layer shear will also be somewhat limited, although HREF guidance does indicate it may be slightly higher in the CSRA which may support at least some multi-cell clusters. Dry air aloft does support the potential for isolated damaging wind gusts in any stronger storms that do form with a secondary but lower hail threat. Still a fair bit of uncertainty in the timing and coverage but in general, expect scattered thunderstorms to develop late this afternoon into evening depending on the exact timing of the shortwave. Lows tonight once again remain mild, in the mid to upper 60s. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... Saturday and Saturday Night: Short wave energy shifting through early on Saturday will allow for an upper trough to deepen over the Carolina coast, followed by ridging gradually building from the west later in the day into Saturday night. On the backside of this system, a northwest flow aloft will develop across the area, advecting somewhat drier air into the area and allowing precipitable water values to fall into the afternoon. This drier air should limit the overall coverage of any convection, with isolated to scattered showers and thunderstorms expected. HREF soundings indicate moderate to strong instability in place with CAPE values between 1500-2000 J/kg. In addition, a pronounced inverted-V sounding and DCAPE values approaching 1000-1200 J/kg would support a damaging wind threat for any storms that do manage to become severe. Overall, the severe threat looks favorable, but with limited storm coverage. Sunday and Sunday Night: Upper level ridging will strengthen over the region with a southerly low-level flow becoming established. A slight increase in moisture advection is expected with precipitable water values rising above 1.5 inches, but strong subsidence aloft and no significant forcing mechanism should limit the coverage of any convection to isolated or scattered at best. The best coverage appears to be across the northern portion of SC in closer proximity to short wave energy shifting across the northern periphery of the ridge. Instability remains moderate to strong across the area. With ample dry air in the mid-levels of the atmosphere there is the potential for a few storms to become strong to severe, with damaging wind once again the primary threat. It should also be noted that Sunday could be one of the warmest days of the period, with heat indices approaching the triple digits in many locations. && .LONG TERM /MONDAY THROUGH THURSDAY/... Heights will fall on Monday in response to an upper trough digging over the Great Lakes region/Ohio Valley, pushing an associated cold front towards the area. Strong diurnal/compressional heating ahead of any front will result in high levels of instability across the area. Isolated to scattered showers and thunderstorms will be expected once again, but with higher levels of instability and stronger forcing ahead of the front, expect a greater overall potential for severe weather across the area. The GFS and ECMWF ensembles show the upper trough axis passing over the area on Tuesday, potentially resulting in the greatest coverage of showers and thunderstorms this week. However, instability appears more limited than previous days, reducing the overall threat for any severe weather. Once the upper trough passes to the east, significantly drier air will overspread the area, greatly reducing the potential for any diurnal convection toward the end of the forecast period. && .AVIATION /15Z FRIDAY THROUGH TUESDAY/... VFR conditions generally expected during this forecast period, outside of any shower-storm activity. Mid-level deck continues to overspread the TAF sites late this morning and into the afternoon. Showers-storms are possible later this evening and into the overnight hours for all TAF sites. Confidence is only high enough for TEMPO mention of TSRA at AGS and DNL, with VCSH at all other sites starting after 20z. Some elevated thunderstorms will likely linger across the area through roughly 08z but confidence is too low in the timing and coverage for a TAF mention past 01z yet. EXTENDED AVIATION OUTLOOK...Restrictions possible at times through early next week in afternoon and evening showers and thunderstorms. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...None. GA...None. && $$ SYNOPSIS... NEAR TERM... SHORT TERM... LONG TERM... AVIATION...