Area Forecast Discussion
Issued by NWS Charleston, SC

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000 FXUS62 KCHS 280235 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 1035 PM EDT Wed Mar 27 2024 .SYNOPSIS... An area of low pressure and an associated cold front will progress through the area tonight and then offshore Thursday morning. High pressure will build in Friday and prevail through early next week. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
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Shower and thunderstorm coverage is beginning to increase from the south and this trend should continue as we move through the night with a front meandering over the area and deep moisture in place (PWats of 1.4 off the 00z KCHS RAOB). Could see some pockets of heavier rainfall with minor ponding on roadways and in poor drainage areas, but widespread flooding issues are not anticipated. Of late, there has also been a couple stronger storms with one report of penny size hail. There is potential for additional storms with stronger updrafts capable of producing hail and stronger wind gusts, though this threat should remain pretty isolated. Highest rain chances should transition towards the coast late tonight with decreasing coverage inland. Breezy conditions will develop just before daybreak for areas behind the front. Lows will range from the mid 50s well inland to the upper 50s at the coast.
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&& .SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/... Thursday and Thursday night: Aloft, a deep trough will swing through the eastern portion of the CONUS during the day and then shift offshore overnight. At the surface, the day will begin with the cold front situated right along the coast with the surface low just to the east. The front will shift offshore in the morning and the post- frontal airmass will steadily filter in through the rest of the day. The most active portion of the entire period will be the morning when the front is still lingering in the vicinity. The eastern half of the forecast area will see scattered to numerous showers for a few hours Thursday morning, and possibly an isolated thunderstorm. These rain chances will quickly diminish from west to east and we should be rain-free by around or just after noon. With the front shifting offshore, winds will be gusty out of the north- northwest with frequent gusts into the 20-25 mph range. Cloud cover will decrease through the day and clear skies should arrive by the evening and prevail through the overnight. Thursday highs are forecast to peak in the mid to upper 60s with overnight lows in the low to mid 40s. Lake Winds: Strong north-northwesterly winds are expected across Lake Moultrie on Thursday as a cold front moves offshore. Gusts could be near 25 knots and a Lake Wind Advisory could be needed. Friday through Saturday: Dry high pressure will build in Friday and prevail into the first half of the weekend. Friday highs are forecast to top out right around 70 with overnight lows mostly in the mid to upper 40s. Saturday will bring a notable warm up with above normal temperatures. Highs are forecast to reach the upper 70s in most areas away from the immediate coastline. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... Broad ridging will gradually build across the eastern CONUS late this weekend and through early next week, with the possibility of the next trough approaching the area by the middle of next week. Dry conditions and warm temperatures are expected through most of the period. Highs are expected to reach the low to mid 80s Sunday through at least Tuesday, with a return to the 70s for Wednesday as a front moves in for Wednesday and also brings our next chance of rain. && .AVIATION /02Z THURSDAY THROUGH MONDAY/... Conditions are expected to deteriorate to MVFR and eventually IFR levels later this evening and overnight as rain and low clouds spread into the terminals. Maintained tempo group for best timing of thunder and lower visibilities. Rain should exit Thursday morning shortly after daybreak, but low clouds will linger through much of the day. VFR should return late in the day. In addition, gusty north winds in the 20-25 kt range will develop as a cold front moves offshore in the morning. Extended Aviation Outlook: VFR conditions will prevail. && .MARINE... Tonight: Showers/tstms will impact the coastal waters overnight as low pressure moves through the area along a quasi-stationary front. Southerly winds will become more southwest overnight. Sustained winds will largely remain below 15 kt outside of tstms. Wind gusts to 35kt could occur with any of the stronger tstms, so Special Marine Warnings may be needed at various times through the night. The cold front is expected to clear the coast just before daybreak Thursday. Winds will pick up quickly after FROPA with gusts near 25 kt. The bulk of these will hold off until after sunrise. Seas will hold 2-4 ft nearshore waters within 20 NM and 4-6 ft over the Georgia offshore waters from 20-60 NM offshore. A Small Craft Advisory continues for the Georgia offshore waters tonight. Thursday through Monday: The cold front will be positioned along or just off the coast Thursday morning. The front and an area of low pressure will move away from the coast through the rest of the day and a period of strong north-northwesterly flow is expected into at least early Friday morning. A period of solid Small Craft Advisory conditions is expected for all waters. The outer Georgia waters advisory is already in effect and runs through Friday morning. We have issued advisories for all nearshore waters, going into effect Thursday morning and then ending at various times Thursday afternoon through late Thursday evening. Frequent gusts into the 25-30 knot range are expected, strongest in the Charleston County waters and the outer Georgia waters. An advisory might also be needed for Charleston Harbor for the daytime hours on Thursday, with gusts near 25 knots. Conditions will improve significantly late Thursday night through Friday morning as the gradient relaxes. Then this weekend into early next week, southwest flow will settle in and prevail with periods of time where wind speeds will surge into the 15-20 knot range at times. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...Small Craft Advisory from 8 AM to 10 PM EDT Thursday for AMZ350. Small Craft Advisory from 8 AM to 6 PM EDT Thursday for AMZ352. Small Craft Advisory from 8 AM to 4 PM EDT Thursday for AMZ354. Small Craft Advisory until 8 AM EDT Friday for AMZ374. && $$ NEAR TERM... SHORT TERM... LONG TERM... AVIATION... MARINE...

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