Area Forecast Discussion
Issued by NWS Charleston, SC
Issued by NWS Charleston, SC
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218 FXUS62 KCHS 030209 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 1009 PM EDT Thu May 2 2024 .SYNOPSIS... Atlantic high pressure will remain across the Southeast through much of next week. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... Late this evening: The main forecast challenge is once again fog and stratus. Overall, we view the forecast as having a large persistence component given that the airmass has not chance appreciably and the setup remains conducive to fog development. Surface winds will be calm for most of the night and we still have plenty of moisture with most sites expected to reach or fall below their crossover temperatures. Given that we had widespread dense fog last night, the potential seems high yet again tonight. The forecast features areas of fog, with patchy dense, just about everywhere. One thing that will be interesting is that near surface flow will be out of the southeast, albeit light. This could help push for just inland of the coast, potentially leaving the immediate coastline mostly fog free. Its not clear how likely this is at this time, but certainly something to consider. Expect a mild night with lows in the low 60s inland and more into the mid 60s closer to the coast. Such values are several degrees above normal for early May. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/... Mid level ridge axis transitions off the Southeast coast Friday with shortwave energy to move through the region over the weekend. High pressure will remain the primary feature at the surface. A few showers and thunderstorms could sneak into inland areas Friday, but convection should be a bit more active over the weekend. Coverage will be highest in the daytime when instability is maximized, but with some upper forcing in play activity will be possible overnight as well. High temperatures generally peak in the mid to upper 80s. Lows only drop to the mid to upper 70s. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... Atlantic high pressure will persist during the early to middle of next week. Convection looks to be most active early in the period, then the chances for showers/thunderstorms decrease towards mid week as ridge rebuilds overhead. Temperatures will also be creeping up, possibly approaching record levels by Wednesday/Thursday. && .AVIATION /02Z FRIDAY THROUGH TUESDAY/... The main forecast challenge for the 00z TAF period will again be fog and stratus. Given that the airmass has changed very little, and the overall setup has changed very little, confidence is relatively high that dense fog will be common across the area. We have not made any significant changes from the 18z TAF`s as we think they reflect the situation very well. Current timing favors fog beginning to develop in the 04-06z time period. We have continued dense fog at all 3 TAF sites bewteen 09-13z. Conditions should return to VFR in the 13-14z time period, and remain VFR thereafter. If there is one potential concern is it is that near surface winds will be out of the southeast, albeit very light. This could help push the fog just inland of the immediate coast. This would be a bigger issue at KJZI than at KCHS or KSAV, but it is something to keep an eye on. There are no significant concerns for afternoon thunderstorms near the terminals on Friday. Extended Aviation Outlook: Flight restrictions possible in overnight/early morning fog and stratus. Isolated to scattered showers and thunderstorms are possible Saturday through Monday. && .MARINE... Tonight: East to southeast winds will prevail tonight with high pressure centered well offshore. Fog could become an issue in the Charleston Harbor as fog oozes into the harbor from nearby areas. The fog could become locally dense with vsbys <1NM. A Marine Dense Fog Advisory could be needed at some point overnight. Fog could impact harbor operations in the Charleston Harbor and Port of Savannah. The fog could not be too much of a concern over the Atlantic coastal waters given the onshore flow regime that is in place. This should limit the fog to areas inland from the beaches. Wind speeds will average less than 10 kt with seas 1-2 ft. Friday through Tuesday: No marine concerns. Atlantic high pressure will maintain rather benign conditions over the marine area. Winds are generally no higher than 10-15 kt with seas 2-3 ft. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$ NEAR TERM...BSH SHORT TERM... LONG TERM... AVIATION...BSH MARINE...