Area Forecast Discussion
Issued by NWS Charleston, SC

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777 FXUS62 KCHS 051414 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 1014 AM EDT Sun May 5 2024 .SYNOPSIS... Atlantic high pressure will remain across the Southeast U.S. through much of next week. A cold front will approach the area on Friday. && .NEAR TERM /THROUGH TONIGHT/...
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A weak shortwave in GA has continued to progress southeast this morning, with convection forming near Charleston County. The associated PV with this wave will meander east off of the coast this morning with skies clearing across most of the area. The 850 MB temperature from the 05.12z KCHS sounding was around 13 degrees C, and with full mixing this would support high temperatures in the mid 80s. The other thing noted from this mornings sounding was the 1.47" PWAT, or a mostly saturated column. However, the sounding was released with a shower close by, so this might be over representing the ambient environment. Either way, MLCAPE values are supposed to be around 1000 J/kg this afternoon with scattered showers and thunderstorms forming along an inland moving sea breeze. This evening, convection should steadily decrease across the forecast, owning to the sea breeze advancing inland and the environment stabilizing after sunset. Patchy fog could develop late tonight, especially over areas of recent rainfall. Low temperatures should favor values between 65-70 degrees.
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&& .SHORT TERM /MONDAY THROUGH WEDNESDAY/... A mid-level ridge axis will be positioned just off the Southeast coast as a shortwave lifts northeast across the Tennessee Valley Monday into Tuesday. Broad Atlantic high pressure will remain the primary surface feature through the period as a low rides across the northern CONUS. Convection will be active Monday with the quick return of deep moisture. Coverage of showers/thunderstorms will be highest in the late afternoon when instability is maximized. The greatest POPs, which top out between 60-70%, are focused in southeast South Carolina and along the I-95 corridor owing to the juxtaposition of upper forcing and a progressive sea breeze. Chances for showers/thunderstorms will be slightly less Tuesday as the deeper moisture and remnant shortwave energy moves off the Mid Atlantic coast in the morning. Although the majority of the forcing will shift offshore, CI could occur along the sea breeze mainly along and west of I-95. A weak ridge will set up Wednesday and little available moisture will keep showers/precip limited. Temperatures will steadily warm each day with highs in the mid 80s Monday and increasing to the low 90s Wednesday. High temperatures Wednesday could even reach record territory (see Climate section below). Min temperatures both Monday and Tuesday are only expected to drop to the mid/upper 60s, with locations along the beaches and Downtown Charleston in the lower 70s. && .LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/... Rainfall chances are little to none to start the long term forecast period as the flow aloft transitions to quasi-zonal. Temperatures will rise into the low/mid 90s Thursday, once again approaching record highs. Dew points will remain in the 60s, which will help keep heat indices from reaching the 100 degree mark. A cold front will approach Friday, pushing across the forecast area Friday night into Saturday, and bringing the next chances for decent convective rainfall. Dry conditions and relatively cooler temperatures (upper 70s/low 80s) are anticipated next weekend behind the front. && .AVIATION /14Z SUNDAY THROUGH THURSDAY/... Prevailing VFR conditions are expected at CHS/JZI/SAV terminals through the 12Z TAF period. Scattered showers, possibly a thunderstorm, may develop just inland of the terminals early this afternoon. The convection should focus along a sea breeze and will track inland during the mid and late afternoon. Extended Aviation Outlook: Brief flight restrictions are possible within scattered showers/thunderstorms Monday and Tuesday. && .MARINE... The surface pattern will yield south-southeast winds between 5-10 kts today, then increasing to 10-15 kts tonight. Wave heights are forecast to favor values between 2-3 ft today and tonight. Monday through Friday: Atlantic high pressure will maintain relatively benign conditions over the local marine waters. Southeasterly winds in the morning will back slightly during the afternoon and evening hours each day as the sea breeze develops. Winds will average 10-15 kt with seas 2-4 ft. Winds will surge near the end of the week as a cold front approaches. Small Craft Advisory conditions are possible as gusts approach 25 kt, but look marginal at this juncture. && .CLIMATE... May 8: KCHS: 93/1986 May 9: KCHS: 95/1963 KSAV: 95/1962 && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$ NEAR TERM...Haines/NED SHORT TERM...BRM LONG TERM...BRM AVIATION...BRM/NED MARINE...BRM/NED