Area Forecast Discussion
Issued by NWS Columbia, SC
Issued by NWS Columbia, SC
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839 FXUS62 KCAE 021824 AFDCAE Area Forecast Discussion National Weather Service Columbia SC 224 PM EDT Tue Jul 2 2024 .SYNOPSIS... Slightly cooler and drier air will spread into the area today. Moisture increases through the week and into the weekend with isolated to widely scattered convection possible each afternoon. Ridging builds into the area late this week and into the weekend resulting in above normal temperatures and Heat Index values near 110 possible. && .NEAR TERM /THROUGH TONIGHT/... Key Message(s): - Dry and seasonably cool tonight Upper ridge centered along the Gulf coast/Lower Mississippi River Valley will be building east. Surface ridge pressure centered over the Mid Atlantic region will extend into the area. Much drier air has advected south into the area from North Carolina. Dew points are falling into the mid to upper 50s. There remains a relatively tight moisture gradient across the southeast Midlands and CSRA where precipitable water is ranging from 2+ inches near a weak frontal boundary in the Low Country and eastern GA to around 1.4 inches near OGB. Think any showers this afternoon will stay mainly south/southeast of the CSRA as focus should be closer to the front. The air mass is stable/moisture shallow and any lift weak. Temperatures in the mid to upper 80s with a few areas around 90 degrees. Mainly clear early this evening, maybe some high clouds coming over Mountains. The models are suggesting some stratus in easterly flow overnight, mainly in the CSRA and southeast Midlands. Overnight lows should be at or slightly below climatology, mid 60s to near 70. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... Key Message(s): - Heat Index values up to 105 possible Thursday afternoon Ridging over the Deep South will remain in place through the short term. Surface high pressure will shift off of the East Coast on Wednesday night, leading to increasing moisture for Thursday. With dry air still in place over most of the area for Wednesday we don`t expect much in the way of rainfall. A few showers/storms will be possible across the southern FA but a subsidence inversion will hinder convection. HREF ensemble members show little or no convective coverage across the southern Midlands and CSRA on Wednesday afternoon. With moisture creeping back into the area on Thursday there may be an isolated shower or weak storm, but again the subsidence inversion will hinder convective development. The higher dewpoints and warmer temps expected on Thursday should push Heat Index values into the 100 to 105 range. Reaching Heat Advisory criteria seems unlikely at this time. Highs will warm through the short term with highs in the mid to upper 90s on Thursday. && .LONG TERM /FRIDAY THROUGH TUESDAY/... Key Message(s): - Heat Advisory Criteria possible Friday through Sunday - Thunderstorm chances increase late this week and this weekend Upper ridging will build eastward over the forecast area in the first half of the long term. Moisture increases through SW flow with mean PWAT values from global ensembles rising to around 2 inches Friday, remaining slightly above normal through the long term. Friday and Friday night: Expect partly cloudy conditions with weak southerly maritime flow increasing the moisture content for the area. Expect an increase in dew point temperatures to the mid 70s. Few showers in the afternoon with low coverage expected due to a capping inversion and ridging aloft. Clouds will slightly offset daytime heating, but expect mid to upper 90`s for high temperatures. Higher humidity for the end of the week will raise peak heat index values above 105 with a max of 110. A weak front will work into the Southeast over the weekend, but will likely remain west of the forecast area, keeping moisture in place. SW flow ahead of the front and convergence from a lee- side trough should promote scattered diurnal convection for the remainder of the long term. However widespread convection is unlikely given the upper ridging. With increasing moisture and warming 850mb temps, we will see highs mainly in the mid to upper 90s this weekend and Heat Index values as high as 110. && .AVIATION /18Z TUESDAY THROUGH SUNDAY/... High confidence for VFR through the evening. A weak front is well southeast of the area, near the SC Low Country and eastern GA. Any showers should remain south of the Terminals this afternoon as much drier air has spread into the area with high pressure building south from VA. Winds will favor northeast to east near 10 knots this afternoon and light east overnight. Cumulus likely to remain southeast of the area and mainly clear sky other than some high clouds through 06z. The guidance is suggesting some stratus will develop late tonight in east flow and spread toward the AGS/DNL terminals. There is a relatively low probability at this time for MVFR/IFR ceilings at those terminals. The guidance has trended less threatening for restrictions. Any low clouds should mix out by 15z Wednesday. EXTENDED AVIATION OUTLOOK...No restrictions expected through midweek outside of some early morning stratus which may briefly become MVFR. Moisture returns late in the week with afternoon showers and thunderstorms possible into the weekend. && .FIRE WEATHER... Key messages(s): -Increased Fire Danger mid to late week. -Rainfall probabilities remain relatively low mid week. Increased fire danger during the Independence Day Holiday week, especially late week as temperatures rise again to well above normal values. Scattered afternoon and evening thunderstorms possibly may aid current dry conditions. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...None. GA...None. && $$ SYNOPSIS...CJR NEAR TERM... SHORT TERM...CJR LONG TERM...CJR/MRM AVIATION... FIRE WEATHER...