Area Forecast Discussion
Issued by NWS Charleston, SC
Issued by NWS Charleston, SC
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704 FXUS62 KCHS 072315 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 715 PM EDT Fri Jun 7 2024 .SYNOPSIS... A cold front will move across the area today. High pressure will return for the weekend, then another cold front is expected to move through area on Monday. The pattern could turn more unsettled through mid to late next week. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... Tonight: Latest radar imagery depicts a seabreeze circulation across coastal counties early this evening, remaining somewhat pinned closer to the coast due to a persistent westerly sfc wind. This feature could initiate a few showers and/or perhaps a thunderstorm during the next couple hours due to some moisture convergence and SBCAPE between 1500-2000 J/kg in the vicinity, but the window for opportunity should diminish shortly after sunset, especially as drier air filters into the region from the west. A sfc boundary/front is then expected to slip across the region early overnight with dry and cooler conditions to follow during the second half of the night. Sfc winds should tip northwest late under clear skies, helping support low temps in the mid-upper 60s inland to low-mid 70s closer to the coast/beaches. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/... Saturday: Northwest upper level flow and weak high pressure will be over the region. Deep, dry air will keep PoPs to less than 10%. However, above normal temperatures are expected, with highs in the in the lower to mid 90s away from the immediate coast, and lows Saturday night in the mid 60s inland to the lower 70s closer to the coast. Sunday: Similar pattern to Saturday, but slightly higher values of deep layer moisture, especially over the northern 1/3 of the area. Could see an isolated very late date/evening shower or thunderstorm, mainly closer to the Charleston County coast and northern Berkeley County. The main trigger for any convection will likely be the seabreeze, along with a weak upper level disturbance glancing by the extreme northern Charleston Tri-county area. Continued above normal Temperatures, with highs in the mid to upper 90s and lows Sunday night in the lower to mid 70s. Monday: A broad and deepening upper level trough is shown by models to move into the eastern U.S., with an associated surface front moving through the region during the day. This front, along with high values of deep layer moisture and lower upper level heights will likely result in scattered afternoon showers and thunderstorms. Right now, chances of any storms to be strong to severe appear to be too low to mention. This may be our warmest day of the week, with highs in the mid to upper 90s. Combining very hot temperatures with increasing low level moisture/humidity will push max Heat indices into the 100-105 degree range. These values are still below Heat Advisory levels, but will feel quite uncomfortable for this time of year. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... Models have been trending for the past several runs for this period to be more unsettled, with increasing deep layer moisture. There is still considerable uncertainty with where and when the best chances for rainfall will be for this period. The latest models seem to point toward later Wednesday through Friday. The general pattern is for a large, unorganized area of low pressure to potentially develop somewhere in the Gulf of Mexico. Most models indicating that at least some of the deep layer/tropical moisture associated with this area could spread northeastward toward our region, especially middle to late next week. Exact QPF values are impossible to pin down at this time. Will also continue to monitor the potential for locally heavy rainfall for this period as well. Temperatures will likely be near to even slightly below normal as increasing moisture/clouds/precip chances help to cut down the daytime heating. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... VFR conditions will prevail at KCHS, KJZI, and KSAV through 18Z Saturday. Extended Aviation Outlook: Saturday and Sunday: VFR conditions expected to prevail at all sites: KCHS, KJZI and KSAV. Monday through Wednesday: Gradual increase in moisture and chances for precipitation, especially by later Wednesday. Scattered convection expected Monday and Tuesday, and Scattered to numerous by Wednesday. Therefore, brief, isolated flight restrictions Monday and Tuesday, then flight restrictions become more likely by later Wednesday. && .MARINE... Tonight: A slightly pinched pressure gradient will persist across coastal waters this evening ahead of a sfc boundary/front expected to shift offshore overnight. Southwest winds upwards to 15-20 kt will be common early evening, then turn more west-northwest and weaken approaching midnight as the gradient begins to relax as the boundary/front shifts offshore. By late night, northwest winds should generally range between 10-15 kt or less. Seas will average between 2-4 ft early, gradually diminishing to 1-3 ft overnight. Saturday through Wednesday: No highlights are expected through the period. A weak front is expected to pass through the waters Monday, then likely stall over or just south of the waters Sunday through mid week. Winds generally 15 knots or less and seas 2 to 3 feet. Increasing chances for showers/thunderstorms by mid week as tropical moisture tries to push northeastward from the Gulf of Mexico. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$ NEAR TERM...DPB SHORT TERM...RFM LONG TERM...RFM AVIATION...Adam/RFM MARINE...DPB/RFM