Area Forecast Discussion
Issued by NWS Columbia, SC
Issued by NWS Columbia, SC
271 FXUS62 KCAE 191847 AFDCAE Area Forecast Discussion National Weather Service Columbia SC 247 PM EDT Wed Jun 19 2024 .SYNOPSIS... High pressure along with dry weather and near normal temperatures are expected through Thursday. Unsettled conditions are possible by late in the week into the weekend as moisture moves in from the Atlantic. Well above normal temperatures are expected by Sunday into early next week. && .NEAR TERM /THROUGH TONIGHT/... Cumulus have once again developed over the area as easterly flow persists due to high pressure off the coast of New England. Aloft the upper level ridge remains centered over much of the eastern US with drier air aloft. With the high and upper level ridge controlling the region the 12z CHS sounding along with with forecast soundings continue showing a strong subsidence inversion over the area. This is apparent in the cumulus which have developed as vertical extent is minimal with the exception in the southeastern Midlands where a bit better developed cumulus are moving in from the coast. Through this evening expect little change with some additional cumulus developing however any potential showers will be confined to the far southeastern Midlands and very southern CSRA as the slightly better developed cumulus move into the area. With sunset and loss of heating the cumulus will dissipate with mostly clear skies overnight. Wind gusts will also diminish with sunset with winds remaining 5 to 10 mph overnight. Afternoon high temperatures remain on track for the low 90s with lows tonight in the mid 60s. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... High pressure remains in place at the surface and aloft Thursday as the pattern will be similar to Wednesday. Weaker onshore flow will lead to less moisture, especially in the low levels so while scattered cumulus may develop, showers are not expected as PWATs will struggle to exceed an inch. High temperatures expected to be near today`s highs. A weaker low level jet Thursday night along with drier conditions should lead to overnight lows being a degree or two cooler, in the mid 60s. Gradual warming expected into Friday as the upper ridge retrogrades and will be centered over the TN Valley. Temperatures at 850mb rise to near or slightly above normal, leading to highs in the low to mid- 90s across the forecast area. A surface trough located offshore will begin to move towards the area around the flow of the upper ridge. This will lead to increasing moisture flowing into the forecast area, although models remain consistent in keeping the deepest moisture to the south. PWATs increase sufficiently to support at least a chance of afternoon showers and thunderstorms south of I-20. This increased moisture will also lead to warmer overnight lows, in the upper 60s to around 70. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... Warming is expected to continue into this weekend as upper ridging continues to hang on over the Southeast. NAEFS indicates that by Sunday and Monday, 850mb temperatures will exceed the 90th percentile. Little change in the overall high temperature forecast in blended guidance or the spread through at least Monday with high confidence (greater than 70%) in high temperatures exceeding 95F each day. With sufficient low level moisture (dew points around 70F), confidence continues to increase in max heat indices reaching or exceeding 100F Saturday through Monday. Also worth noting that blended guidance continues to favor warm overnight lows, remaining in the low to mid 70s. There remains uncertainty beyond Monday as guidance continues to show the ridge beginning to break down as an upper trough approaches the region and blended guidance begins to show greater spread in temperatures. That being said, no major cool down is expected anytime soon. GEFS probabilities indicate increasing probability of PWATs increasing to above 2 inches by Sunday into early next week which will lead to increasing chances for diurnally driven thunderstorms. With the potential for greater dynamics with an approaching upper trough, highest chances for showers and thunderstorms will be Monday and Tuesday. More information on the potential for moderate to major heat risk late in the forecast period can be found at wpc.ncep.noaa.gov/heatrisk. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... VFR through the TAF period. High pressure remains in control of the region with easterly winds and scattered cumulus across the terminals. Through this evening expect the cumulus to continue developing then dissipate with sunset with mostly clear skies overnight. Winds will remain easterly through the period with gusts around 18 knots into this evening then diminishing to 5 to 8 knots overnight. As the morning inversion breaks winds will return to around 10 knots with gusts up to 18 knots from 15z through the end of the period. EXTENDED AVIATION OUTLOOK...Brief restrictions possible in isolated to scattered afternoon and evening thunderstorms Friday through Sunday. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...None. GA...None. && $$