FXUS62 KCHS 261806 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 206 PM EDT Fri Apr 26 2024 .SYNOPSIS... High pressure will prevail through much of next week. A weak cold front could approach late next week. && .NEAR TERM /THROUGH TONIGHT/... Cloud cover has indeed mixed/scoured out over the last few hours, save for a narrow corridor of marine stcu tucked along the coast. Added sunshine has cranked up surface temps nicely into the middle and upper 70s...touching 80 in southeast Georgia. Some additional tweaks to cloud cover/temps were made with the early afternoon update. Previous discussion... Morning surface analysis reveals a wedge of high pressure nosing down through the Carolinas into Georgia. Developing northeasterly flow has driven a wedge of cooler low level air into the region during the overnight/early morning hours and lead to a round of unauthorized low stratus and fog, facilitated by moist flow off the Atlantic. Morning satellite imagery also reveals a "wing" of thick mid cloud cover spreading into the northern part of the forecast area, which is not helping the cause of eroding the lower stratus. Rest of today: Surface high pressure remains wedged across the mid Atlantic and southeast through the day with persistent easterly flow off the Atlantic. But, we remain optimistic that with continuing heating and mixing, we will erode away the lower cloud cover late this morning/early afternoon, although the thicker mid cloud cover will probably keep things on the partly sunny side of things...at least across the northern part of the forecast area. We have made adjustments to forecast max temps and sky cover accordingly, with additional adjustments likely. Tonight: The synoptic pattern will change little tonight with sprawling 1035 hPa high pressure extending south over the Southeast States and strong subtropical ridging aloft. A fairly tight surface pressure gradient associated with the high itself will hold through the night which should keep the atmosphere somewhat mixed through daybreak Saturday. Onshore winds will likely keep some degree of marine-based stratocumulus moving onshore, but models appear to be struggling a bit on exactly how much cloud cover will occur. Partly cloudy conditions were favored, but adjustments to this will likely be needed as cloud trends become a bit more apparent. Low will range from the upper 50s well inland to the upper 60s at the beaches. A few beach spots along the Georgia coast, such as Tybee Island, may not drop below 70. && .SHORT TERM /SATURDAY THROUGH MONDAY/... A strong upper ridge axis will remain directly over the area Saturday into Sunday while cool surface high pressure remains to the north. Weak ENE to E winds will prevail through the weekend. Low-level onshore flow is expected to bring enough moisture into the area to allow scattered to broken stratocumulus to develop during peak heating hours. High temps both days will be in the upper 70s to around 80. The deep layered ridge shifts off the coast by Monday, with a southerly flow setting up in low levels. Less cumulus development expected on Monday, and warm advection will push highs into the low to mid 80s. && .LONG TERM /MONDAY NIGHT THROUGH THURSDAY/... Mainly dry weather expected through the extended as a zonal flow develops aloft and surface high pressure remains over the western Atlantic. Warm advection and ample sunshine will yield a warming trend with highs back in the upper 80s to lower 90s by mid to late week. && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/... 26/18z TAF Discussion: KCHS/KJZI/KSAV: Low stratus has eroded leaving VFR conditions in place...save for a narrow corridor of MVFR marine stratocu tucked along the coast and impacting KJZI. Other than a brief period of MVFR conditions at KJZI, VFR will be the rule through the afternoon hours into this evening at all terminals. Gusty easterly winds persist through the afternoon with gusts 20 to 25 knots common. Winds will subside around and after sunset. With persistent easterly flow off the ocean, it's possible we get the return of low stratus into the terminals later tonight, although our forecast confidence is not high enough to go full in MVFR/IFR. But, we have introduced a few-sct lower cloud layer to all terminals. Barring low cloud cover around Saturday morning, VFR conditions are anticipated through the balance of the terminal forecast. Extended Aviation Outlook: Prevailing VFR. && .MARINE... Prevailing northeasterly winds over top the sea breeze is producing some stout wind gusts along the South Carolina coast this afternoon. Enough so to hoist a Small Craft Advisory until early evening with gusts to around 25 knots. Previous discussion... Today: Easterly winds will slowly build through the day as high pressure noses in from the north. Winds will reach 15-20 kt in the South Santee-Edisto Beach nearshore leg out 20 NM with slightly lower winds expected elsewhere across the local marine area. A robust sea breeze appears likely in the Charleston Harbor this afternoon. Winds should peak in the 15-20 kt range with waves building 1-2 ft. It will be close to Small Craft Advisory levels (Charleston Harbor criteria is sustained 20 kt or frequent gusts to 25 kt), but it appears that both sustained wind and wind gusts will fall just shy of advisory thresholds. Seas will average 2-4 ft. Tonight: East winds around 15 kt will hold through the night. Sea breeze enhancements in the Charleston Harbor will diminish early in the evening. Seas will build to 3-5 ft and possibly as high as 6 ft in the Georgia offshore leg out 20-60 NM. There is some uncertainty if 6 ft seas will reach the Georgia offshore waters by sunrise Saturday with the latest NWPS and WaveWatch showing slight timing differences on the arrival of 6 ft seas. A Small Craft Advisory will not be issued just yet given these timing differences. The need for an advisory will be reconsidered later today. Saturday through Tuesday: Fairly long ENE fetch may bring some 6 ft seas into the offshore GA waters late tonight or Saturday morning, then continuing into Sunday before dropping back below 6 ft. A short-duration Small Craft Advisory may be needed. Otherwise, marine conditions will remain fairly quiet with E winds this weekend becoming SE early next week, then S by mid next week. Rip Currents: Moderate onshore winds will continue through the weekend, while approximately 3 ft waves every 6-7 seconds hit the beaches. Local rip current calculator indicates low risk for Saturday, but the Rip Current MOS shows Moderate for the GA beaches, so we are carrying Low for SC and Moderate for GA. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...Small Craft Advisory until 8 PM EDT this evening for AMZ330- 350. && $$ NEAR TERM...Adam AVIATION...Adam MARINE...Adam