Area Forecast Discussion
Issued by NWS Columbia, SC
Issued by NWS Columbia, SC
583 FXUS62 KCAE 040555 AFDCAE Area Forecast Discussion National Weather Service Columbia SC 155 AM EDT Thu Jul 4 2024 .SYNOPSIS... Moisture increases through the week and into the weekend with isolated to scattered showers and thunderstorms possible each afternoon. Above normal temperatures are expected and Heat Index values around 110 are possible Friday through Sunday. Atmospheric moisture remains high through the long term supporting a chance of rain each day. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... Key Message(s): - Low-level Moisture increasing tonight The surface ridge will shift east tonight and the moisture will increases a result. Forecast soundings indicate that the majority of the moisture increase will be in the low levels. While there is the possibility of some low stratus developing tonight, there remains a decent amount of low level dry air to overcome. Guidance temps consistent with lows in the low to mid 70s. && .SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY NIGHT/... Key Message(s): - Heat Index values up to 110 possible Friday. A Heat Advisory may be needed. Upper level ridging will build over the Forecast Area (FA) during the short term as low level moisture increases through southerly flow. The main concern for the period will be Friday afternoon where Heat Index values should reach the 105 to 110 range. With PWAT values increasing to near 2 inches on Friday and upper ridging over the FA there should be sufficient heat and moisture to raise heat-related illness concerns and may prompt a Heat Advisory. Thursday afternoon appears too dry to meet criteria with afternoon dewpoints mixing into the 60s. Showers are unlikely Thursday due to a drier airmass and warm temps aloft. However we can`t rule out an isolated shower or weak storm in the afternoon. A low number of HREF and SREF members have convective precipitation on Thursday afternoon. On Friday, with temperatures reaching near 100 degrees, closer to the convective temperature, and PWAT values from 1.75 to 2 inches, we are more likely to see isolated or widely scattered storms. Forecast soundings show a tall, skinny CAPE profile indicating limited potential for severe weather. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... Key Message(s): - Increased risk of heat-related illnesses this weekend - A Heat Advisory may be needed Saturday and Sunday Moisture continues to increase through the weekend with hot and humid conditions expected through early next week. Heat Index values on Saturday and Sunday of around 110 degrees are possible. Considering non-environmental factors of being a holiday weekend and increased exposure, the risk of heat-related illnesses could be higher than normal. A Heat Advisory may be needed for Saturday and Sunday. However the possibility for decent convective coverage does limit confidence in reaching criteria. Ridging should remain over the Southeast despite an upper trough expected to move through the Great Lakes region Friday and into northern New England on Saturday. A frontal boundary, associated with the trough, will approach the Southeast with significant moisture pooling over our FA. This pattern supports increasing rain chances in the long term with PWAT values slightly above normal. The upper ridge may limit widespread convection, but we should see a chance of rain each day through the extended. The highest rain chances may be Sat and Sun with the weak frontal boundary in the vicinity before it becomes diffuse early next week. Isolated strong or severe storms are possible as afternoon CAPE values increase due to the higher moisture. Near or above normal PWAT values continue through the end of the forecast period supporting climatological rain chances through the long term. && .AVIATION /06Z THURSDAY THROUGH MONDAY/... VFR conditions expected through the period, however some low confidence restrictions are possible during the early morning and sunrise hours. High cirrus is moving across the area, helping prevent any low cloud cover or fog as of 06z. Some clearing is possible closer to sunrise and therefore some stratus-fog development. Confidence however is too low for an explicit TAF mention at this time for AGS, DNL, and OGB so continued a 6SM and SCT007 tempo group at those sites; CAE and CUB are more likely to not see any sort of fog- stratus. Winds will pickup out of the south for all sites mid- morning, 5-7 knots with some typical summer cu field development between 2500-4000 ft. EXTENDED AVIATION OUTLOOK...Increasing chances of showers and thunderstorms and associated restrictions Friday through Monday. && .FIRE WEATHER... Key messages(s): -Hot and dry conditions continue through Independence Day -Rainfall probabilities increasing Friday through early next week Hot and dry conditions will continue through Independence Day with increasing moisture and chances of showers and thunderstorms Friday into early next week. Although there was some rain late in the weekend and into early this week the hot and dry conditions over the past few days and through Thursday will generally minimize any improvement from the rain. Moisture will begin increasing Thursday with scattered afternoon and evening thunderstorms beginning Friday mainly along and north of I-20 then spreading eastward Saturday into early next week. Temperatures will also be a concern with afternoon highs in the upper 90s to around 100 which will push heat index values to around 105 Thursday and 110 Friday and Saturday. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...None. GA...None. && $$ SYNOPSIS... NEAR TERM... SHORT TERM... LONG TERM... AVIATION... FIRE WEATHER...