Area Forecast Discussion
Issued by NWS Columbia, SC
Issued by NWS Columbia, SC
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996 FXUS62 KCAE 062200 AFDCAE Area Forecast Discussion National Weather Service Columbia SC 600 PM EDT Sat Jul 6 2024 .SYNOPSIS... Moisture increases, with scatter to numerous showers and thunderstorms expected through the weekend. Above normal temperatures are expected again, with Heat Index values above 100 each day through next week. Atmospheric moisture remains high through the long term supporting a chance of showers and thunderstorms each day. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... Update...Showers and thunderstorms across much of the area have cooled temperatures considerably with corresponding heat index values in the mid 90s or lower. This has resulted in the heat advisory being cancelled. Previous discussion... Key Message(s): - Scattered to numerous showers and thunderstorms. - Isolated Flash Flooding possible Temperatures have risen into the lower to mid 90s. Combine these temps with dew points in the mid to upper 70s, we`re already seeing heat index values over 105F in a number of locations. With a few hours of heating left, still expecting heat index values to near 110F this afternoon. Meanwhile, the cumulus field is becoming more agitated with some shower activity beginning to show up on radar. Expect the showers and thunderstorms to increase in coverage this afternoon into the evening. MLCAPE values are ranging in the 1500-2000 J/kg range; however, there isn`t much shear to speak of, so the severe threat today continues to be minimal. PWAT values are currently over 2.0 inches across the area and are expected to remain high. Thus, there is potential for locally heavy rain to cause isolated urban or flash flooding today. Rain and thunderstorm chances gradually diminish overnight with temperatures remaining mild in the mid to upper 70s. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/... Key message(s) - Not quite as hot with an increase in convective activity. Surface boundary stalled across the area will be the primary focusing mechanism for afternoon shower and thunderstorm develop once again on Sunday. Upper trough sets up across the middle of the U.S., with the southeastern States still on the western edge of the Atlantic Ridge aloft. Southwesterly winds aloft begin bringing more Gulf moisture into the area. By Monday the surface boundary will dissipate, and the main focus will be from left over convective boundaries, along with possible sea-breeze activity. Temperatures will cool slightly with the expected increase in cloud cover through the period, but will still be from around 90 to the middle 90s. Heat index around 100 both days. && .LONG TERM /TUESDAY THROUGH SATURDAY/... Key Message(s) - Continued with a more typical summertime weather pattern. Pattern will be somewhat stagnant aloft through the period. Upper trough remains across the middle of the country, with our area on the western portions of western Atlantic ridge. This general pattern will keep upper winds more out of the southwest, bringing Gulf moisture towards the region, while at the surface winds will be more out of the south to southeast allowing Atlantic moisture to move inland. Triggers for any afternoon convection will be inland moving sea-breeze and associated outflows moving in from the east, along with potential for lee- side trough over the west. There should be more cloud cover move across the region each day, so afternoon highs are expected to stay away from the century mark, with readings mainly in the lower to middle 90s. However with all the moisture in low- levels, heat index values will be able to rise back above 100 degrees through much of the period. && .AVIATION /22Z SATURDAY THROUGH THURSDAY/... VFR conditions through much of the TAF forecast period with restrictions in afternoon convection and early morning fog/stratus possible. Showers and thunderstorms have currently moved away from the terminals however potential for cells to move into the terminals over the next several hours remains possible. Will continue to handle with a TEMPO group attm and adjust accordingly with much of the convection expected to diminish with sunset. Next concern will be for stratus and fog development as the moisture becomes trapped under the inversion. Have remained with MVFR stratus predominately however vsby and potential for IFR cigs will depend on final rainfall and continue to be monitored. EXTENDED AVIATION OUTLOOK...Restrictions possible in diurnally driven showers and thunderstorms each day. Sunday is expected to have the highest coverage in the extended period. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...None. GA...None. && $$