Area Forecast Discussion
Issued by NWS Columbia, SC
Issued by NWS Columbia, SC
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417 FXUS62 KCAE 170726 AFDCAE Area Forecast Discussion National Weather Service Columbia SC 326 AM EDT Fri May 17 2024 .SYNOPSIS... Chances of showers and thunderstorms will increase this afternoon as a weak system begins to slowly cross the region with shower and thunderstorm chances likely lingering into Sunday. A cooler and drier air mass moves in for Monday and Tuesday with temperatures rebounding during the middle of next week as another ridge moves in from the west. && .NEAR TERM /THROUGH TONIGHT/... Upper level ridging currently over the area will continue moving eastward as the next system moves through the Gulf States. Through daybreak winds will remain light and variable with cirrus clouds moving in from the west. Expect some patchy fog to develop mainly in fog prone locations and near area lakes and rivers. Overnight lows will be in the low to mid 60s. Change will begin this morning as winds turn south to southwesterly. Although speeds will be less than 10 mph this will begin advecting Gulf moisture into the area. By early afternoon pwats will have crossed 1.5 inches and 1.8 inches by early evening. Although this system is lacking a strong trigger mechanism and mid level lapse rates will be around 5.0 C/Km there is potential for strong heating should the cirrus be thinner than expected. Current satellite imagery shows an extensive cirrus deck over the western and central Gulf Coast however much of this is due to a weakening MCS. Even with the MCS cloudiness dissipating as it weakens expect the increasing and lowering clouds through the day to limit heating and keep the best chance of thunderstorms across the southern Midlands and CSRA. SPC outlook has the area in general thunder with a slight risk over the central Gulf Coast and should this area become active it is possible for some to push into the CSRA during the evening into early overnight hours. Overall agree with the SPC outlook while there is potential across the forecast area it is limited. Moisture and isentropic ascent also increase through the evening into the overnight hours and with pwat values increasing to 2 inches or better at times there is potential for some locally heavy rainfall. Flow aloft will be 40 to 50 knots so do not expect any hydro related issues attm however will continue to monitor. High temperatures this afternoon will range from the low 80s in the western Midlands and northern CSRA to the mid 80s elsewhere. Overnight lows will be in the mid 60s to around 70. && .SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/... Saturday`s forecast is at least interesting, but skepticism regarding overall severe threat is fairly high. While ensemble guidance is fairly bullish with probability for some instability & shear across the southern FA, clouds are expected to be widespread and with at least some rain remaining across the area, it is uncertain whether we`ll be able to destabilize enough or not. Synoptic forcing looks good, but there is not a strong, definite low-level forcing mechanism that would focus convection. CSU probabilities are elevated across the southern FA and that is definitely the spot if we have severe convection Saturday. Highs on Saturday are very dependent on cloud cover, but should range from the upper 70s to the mid 80s across the FA. Some shower activity will probably hang around thru the overnight hours, with lows falling into the mid 60s. && .LONG TERM /SUNDAY THROUGH THURSDAY/... Continue to expect showers and thunderstorms on Sunday afternoon as the upper level trough swings overhead. The cool mid-level temps could actually yield a favorable environment for strong thunderstorms on Sunday afternoon, so we will need to keep an eye on model trends over the next couple of days. There after, cooler air pushes in on Monday and maybe Tuesday as surface high pressure ridges into the region. Some indication of weak wedge conditions setting up on Monday but it is so climatologically unfavored this time of year that we will need more model guidance to actually delineate whether or not that happens. Ridging is expected to push over head through the remainder of the period, with seasonally low chances for rainfall and above normal temps by this time next week. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... Generally VFR conditions expected through the TAF period. Thin cirrus have begun to overspread the region and will gradually become thicker through daybreak. Main question remains will the cirrus be thick enough to limit fog and stratus development. Although there is currently a 20 knots LLJ shown on CAE WSR-88D and cirrus moving in satellite imagery also show some patchy fog developing around AGS. As such have remained with TEMPO MVFR at AGS/OGB during the early morning and sunrise hours. Fog and restrictions will mix out quickly with sunrise. With winds turning S to SW Gulf moisture will be moving into the area with clouds lowering and thickening as well. Expect showers to move into AGS/DNL around 23z and spread into the other terminals by 17/01z with MVFR cigs and vsbys through the end of the period. EXTENDED AVIATION OUTLOOK...Increasing confidence in restrictions in showers and thunderstorms continuing through Sunday night. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...None. GA...None. && $$