


Area Forecast Discussion
Issued by NWS Charleston, SC
Issued by NWS Charleston, SC
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081 FXUS62 KCHS 041447 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 1047 AM EDT Fri Apr 4 2025 .SYNOPSIS... Strong high pressure centered over the Atlantic will prevail into this weekend. A cold front will push offshore Monday with high pressure prevailing for much of next week. && .NEAR TERM /THROUGH TONIGHT/... Today: An impressively strong and deep-layered anticyclone will remain centered just off the Southeast Coast, leading to large-scale subsidence and mostly dry/warm coniditons across the local area. Southerly sfc winds along the western periphery of the sfc ridge along with breaks in clouds (especially behind a developing sea breeze) will allow for rapid warming. 1000-850mb thickness levels support highs in the mid-upper 80s for most areas, but highs could reach the lower 90s across inland areas of Southeast Georgia. Although large-scale subsidence will keep most areas dry, a few afternoon showers remain possible well inland where subsidence is slightly weaker, PWATs remain in the 1-1.25 inch range, sfc heating is stronger and SBCAPE approaches 2000 J/kg. Precip coverage should remain isolated and rainfall accumulations on the lighter end given the synoptic setup. Tonight: With loss of insolation and the sea breeze having cleared the entire region by around 8 PM, any isolated showers early will have come to an end. There is little change in the overall pattern surface and aloft, under the control of strong deep-layered ridging. There`s a bit less moisture in the lower levels, so the stratus/stratocumulus will not be quite as extensive as recent nights. With less cloud cover expected, and a little less wind in the boundary layer, lows are forecast to be a tad lower than they were last night. We presently have lower and middle 60s inland, with upper 60s closer to the coast. But if winds are higher and/or cloud cover is more extensive (as shown by some simulated satellite guidance), min temperatures would be a bit warmer. Either way it`ll be far above climo. No mention of fog just yet, but it does remain possible, especially if stratus build down occurs. && .SHORT TERM /SATURDAY THROUGH MONDAY/... Deep layered high pressure off the Southeast coast will continue to hold influence over the local weather Saturday into Sunday. This pattern will favor dry and warm conditions. Away from the beaches, temperatures will peak around 10 degrees above climo with highs in the mid to upper 80s, potentially touching 90 in spots. Lows will be quite mild, only falling to the mid-upper 60s. These values are within a couple degrees of daily record high minimums for April 6. Otherwise, gusty south winds will develop each afternoon, especially on Sunday ahead of an approaching cold front. Mid level ridge will weaken Sunday night into Monday as a trough and accompanying cold front shifts towards the East Coast. Airmass will be juicy with models indicating PWats surging to near/over 1.75". Given large scale forcing ascent, showers with embedded thunderstorms are expected to spread across the area. While rain chances will increase Sunday night, the bulk of activity is expected to occur during the daylight hours on Monday. Strong wind fields will be in place with deep layer shear increasing to over 50 knots which could promote some storm organization, although instability is not particularly impressive. Radar will certainly bear watching. Temperatures will be tricky with incoming convection. Current high temperature forecast spans the 70s, coolest inland. && .LONG TERM /MONDAY NIGHT THROUGH THURSDAY/... A cold front and its associated rain chances will exit off the coast Monday night. Dry and quiet weather is then expected through midweek as high pressure returns. Most notably will be the drastic change in temperatures. After the extended stretch of heat we will have experienced, temperatures will drop back below climo. Overnight lows are set to fall into the 40s both Tuesday night and Wednesday night. Another cold front could approach late next week. && .AVIATION /15Z FRIDAY THROUGH TUESDAY/... KCHS/KJZI/KSAV: Flight restrictions will continue at all terminals through the morning, generally down in the low-end MVFR range. KCHS and KJZI will fluctuate between VFR and MVFR based on recent satellite trends. It`ll take until 17Z before VFR makes a return at all terminals. As mixing heights climb during the late morning and this afternoon, S winds will gusts frequently near 20 kt, before the gusts drop off with sunset. Mixed signals regarding how much low cloud cover returns tonight. For now kept it VFR, but flight restrictions are again possible. Extended Aviation Outlook: Gusty winds are expected on Sunday. Flight restrictions are likely Monday as showers with a few tstms impact the area ahead of a cold front. && .MARINE... Today and Tonight: Strong Atlantic high pressure will encompass the local waters, leading to southeast/south winds around 15 kt or less. The exception will be in Charleston Harbor, where sea breeze influences generate some gusts around 20 kt this afternoon. Seas are a mixture of swells and wind driven waves, equating to significant wave heights of 3-4 ft within 20 nm of the coast, and 4-5 ft across the outer Georgia waters. Guidance remains overdone on sea fog, as it has been lately. Much of the guidance is initially showing sea fog already occurring, when it is not. Winds are a bit too high for its occurrence, so no mention is necessary in the forecast. Saturday through Wednesday: Southerly flow will persist through the weekend as the region remains on the backside of surface high pressure. Speeds and seas will ramp up Saturday night into Sunday as a cold front approaches the region, with conditions remaining elevated into Monday. Small Craft Advisories could be needed. The cold front will cross the waters later Monday, with flow turning more northerly for Tuesday in its wake. Conditions are expected to fall below Advisory criteria, although another brief surge is possible Tuesday night into Wednesday as high pressure builds. Rip Currents: Lingering 3 ft swells every 8 to 10 seconds will support a moderate risk for rip currents for all beaches today and Saturday. An elevated risk of rip currents will likely persist into early next week. && .CLIMATE... Record High Temperatures: April 5: KSAV: 90/1988 April 6: KSAV: 90/1967 Record High Minimum Temperatures: April 3: KCHS: 67/2012 KCXM: 68/2012 KSAV: 68/2012 April 4: KCHS: 70/1974 KCXM: 69/1974 KSAV: 69/1974 April 5: KCHS: 65/2017 KCXM: 67/2023 KSAV: 66/1957 April 6: KCHS: 68/2023 KSAV: 68/2023 && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$ NEAR TERM...DPB SHORT TERM... LONG TERM... AVIATION... MARINE...DPB