Area Forecast Discussion
Issued by NWS Columbia, SC
Issued by NWS Columbia, SC
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460 FXUS62 KCAE 060106 AFDCAE Area Forecast Discussion National Weather Service Columbia SC 906 PM EDT Fri Jul 5 2024 .SYNOPSIS... Moisture increases into the weekend with isolated to scattered showers and thunderstorms each day. Above normal temperatures are expected again Saturday with Heat Index values up to 110 possible. Atmospheric moisture remains high through the long term supporting a chance of showers and thunderstorms each day. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... Key Message(s): - Another muggy night with isolated showers and storms lingering into the overnight hours. Lingering convection this evening developing along outflow boundaries but coverage continues to decrease and cloud tops are warming on satellite imagery. Isolated showers and maybe a storm overnight but coverage will be limited. Otherwise, expect similar conditions to last night with temperatures falling slowly but bottoming out in the mid to potentially upper 70s as a southwesterly low level jet remains over the area ahead of a cold front to the NW of the area, moving into the TN Valley. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/... Key Message(s): - Heat Indices as high as 110 degrees Saturday. A Heat Advisory may be needed. - Scattered to numerous showers and thunderstorms this weekend. - Isolated Flash Flooding threat over the weekend. Main upper trough axis will continue across the middle of the country through the weekend, with some upper ridging still being indicated across the forecast area. At the surface, a decaying surface front will move into the cwa, which will at least enhance lift somewhat. Add in high pwat values above the 2 inch mark, and some instability by the afternoon each day, and we should see scattered to possibly numerous showers and thunderstorms developing bot Saturday and Sunday. High pwat readings and potentially slower moving storms could lead to some heavier rainfall at times. Another day of higher heat indices are expected to be high over the weekend. Afternoon highs in the middle 90s,and a good amount of moisture, will lead to heat index readings above 105 to 110 for a period Saturday. Can not rule out another Heat Advisory through the afternoon, but will wait until the current Advisory expires this evening before possibly pulling the trigger on that. There is still some uncertainty as to exact heat index values, mainly due to when convection starts and how much cloud cover gets created by that. Earlier convection and clouds would keep slightly cooler readings, while later convection and more sunshine will more than likely cause readings to rise to advisory criteria. Sunday will be slightly cooler with more clouds, and this will keep heat index readings between 95 to 105 degrees. && .LONG TERM /MONDAY THROUGH FRIDAY/... Key Message(s): - After Monday, heat indices climb back over 100 degrees. - Daily diurnal convection expected. We get back into a slightly more typical Summertime pattern through the week. Pwat values remaining relatively high, at or above 2 inches, with continued upper ridge just off the east of the region across the western Atlantic. The main upper trough axis continues to be west of the area, with stronger dynamics deflecting further off to the north through the period. With plenty of moisture, and afternoon highs forecast in the low to mid 90s each day, much of the guidance shows high likelihood for diurnal showers and thunderstorms. With the high pwat values, any slow moving storms could produce periods of heavy rainfall. In addition, can not rule out an isolated severe thunderstorm threat. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... VFR conditions expected through the TAF period with increasing potential for convection. Showers and thunderstorms are currently just west of CAE/CUB and have updated to include TEMPO through 02z for mention of thunderstorms along with some gusty winds. By 03z expect convection to have dissipated however clouds will linger overnight. With a LLJ also over the area the threat for low clouds and fog remains too low to include. With sunrise and onset of heating cumulus will again be developing with showers and thunderstorms developing shortly after midday. Have included VCSH for all sites from 17 or 18z through the end of the period and will adjust as confidence in timing and coverage improves. EXTENDED AVIATION OUTLOOK...Restrictions possible in diurnally driven showers and thunderstorms each day. The greatest convective coverage expected Sat/Sun afternoon. && .FIRE WEATHER... Although conditions remain dry across the area the South Carolina Forestry Commission reported less fire activity today than expected. There were some showers and thunderstorms in the northern CSRA and western Midlands this afternoon and evening however this will not be enough to eliminate the dry conditions across the area. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...None. GA...None. && $$