Area Forecast Discussion
Issued by NWS Charleston, SC
Issued by NWS Charleston, SC
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576 FXUS62 KCHS 010212 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 1012 PM EDT Tue Apr 30 2024 .SYNOPSIS... A weak disturbance will move through the region tonight into Wednesday. High pressure will then prevail through late week, before a weak cold front stalls in the vicinity this weekend. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... Late this evening: While most of the convection from earlier weakened, there was one cluster of thunderstorms that managed to strengthen as it pushed to the northeast across Hampton, Allendale, and into Bamberg and northern Colleton counties. This storm pulsed up to become strong enough to warrant a Special Weather Statement and might have been strong enough to produce large hail as it crossed into Bamberg. Otherwise, the trailing convection looks quite weak but will still be enough to produce some brief downpours over the next few hours. Isolated to scattered showers and storms still looks like the best coverage and there is no significant change to the forecast thinking through the overnight. As we go through the evening and overnight, the shortwave will continue progressing eastward and the forecast area will remain within the forcing associated with it and the deeper moisture noted above. Instability will certainly be quite low in the absence of surface heating, but we should continue to see isolated to scattered showers and thunderstorms across the area for much of the overnight. The trough axis should shift offshore just before sunrise and the convective coverage is expected to diminish. There is no severe threat, but we could still see some localized heavy rainfall totals. On the backside of the shortwave and the departing convection, light winds and plenty of residual low-level moisture should be sufficient to produce at least some patch fog across the inland tier of the forecast area. That has been added to the forecast. Lows are expected to be a few degrees warmer than last night, with low to mid 60s across the area. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/... Mid level shortwave will shift off the Carolina coast Wednesday morning. Convection should be limited in wake of this feature, but a few isolated showers/thunderstorms will still be possible through the day with lingering moisture and instability, especially along the coast. Ridge builds overhead on Thursday before transitioning offshore on Friday in advance of a weak shortwave moving in. This pattern will largely act to suppress convection but will need to monitor potential for a few storms to impact far inland areas later Friday. High temperatures peak in the mid to upper 80s inland of the immediate coast. Lows will span the 60s, coolest inland. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... Surface high pressure remains the primary feature, although a weak front will approach the region and stall before largely dissipating. Aloft, a series of weak shortwaves will pass through. Expect at least isolated to scattered showers and thunderstorms each day. Highs remain in the mid/upper 80s, while lows stay in the 60s. && .AVIATION /02Z WEDNESDAY THROUGH SUNDAY/... Afternoon convection has mostly remained west of the terminals, but that should change through the evening and into the early morning hours. Current thinking is that the best chances for direct impacts will be at KCHS and KJZI. Therefore we have gone with prevailing VCSH beginning at 02, with a TEMPO group from 04-08 to cover periods of possible MVFR conditions as showers move through the terminals. The potential at KSAV certainly isn`t zero, but based on the current upstream interaction of the sea breeze and outflow boundaries, it will likely remain just to the north. There could be some fog and stratus development around sunrise, but it is expected to remain inland of the terminals. Winds will be northwesterly Wednesday morning and into the early afternoon before the sea breeze moves through and brings winds around to be southerly. We will also have to watch for isolated shower and thunderstorm development along the sea breeze beginning in the early afternoon, but confidence in direct impacts at the terminals is too low to include anything in the 00z TAF`s. Extended Aviation Outlook: Flight restrictions possible in overnight/early morning fog and stratus. && .MARINE... Tonight: High pressure centered across the western Atlantic will extend toward the Southeast Coast while a trough remains inland. The pattern will favor a southerly sfc wind around 15 kt or less across local waters with the exception of the Charleston Harbor into early evening, where 20 kt gusts are possible. Seas will range between 2-4 ft, largest across offshore Georgia waters. Mariners should remain alert for thunderstorms tonight, producing gusty winds and frequent lightning strikes. Wednesday through Sunday: No marine concerns expected. Atlantic high pressure will remain the dominant feature with a relatively weak gradient in the area. Wind speeds will generally stay below 10 kt except right along the coast with the afternoon sea breeze, and seas will mostly run 2-3 ft. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$ NEAR TERM...BSH SHORT TERM...ETM LONG TERM...ETM AVIATION...BSH/ETM MARINE...DPB/ETM