Area Forecast Discussion
Issued by NWS Charleston, SC
Issued by NWS Charleston, SC
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439 FXUS62 KCHS 101347 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 947 AM EDT Fri May 10 2024 .SYNOPSIS... A cold front will push offshore today. High pressure will prevail for the weekend into early next week. A storm system could affect the area by the middle of next week. && .NEAR TERM /THROUGH TONIGHT/... This morning: A large area of mostly stratiform rain and embedded weakening convection continues to track eastward across the forecast area. We have cancelled all of the Severe Thunderstorm Watch, except for McIntosh County which is closest to the best available instability. Overall, the severe threat is rapidly diminishing, even for McIntosh County. The area of stratiform rain is also steadily shrinking, and potential rainfall amounts through late morning continue to diminish. By around midday or so, the stratiform rain should dissipate completely and we should be rain-free by the early afternoon. Attention then turns to the upstream cold front and isolated to scattered convection that should develop along it across the Midlands. This activity could then track into portions of the forecast area late this afternoon and into the early evening. With the widespread cloud cover and rainfall moving through the area currently, it seems unlikely we will be able to recover and destabilize sufficiently to produce much of a severe weather threat this afternoon and evening. If there is an area with a risk, it would be the Charleston Tri-County area and Colleton County. High temperatures will be tricky and warming will be delayed due to the ongoing rainfall and cloud cover. We still think low 80s for highs is on track. The cold front is timed to push off the coast by midnight. In the wake of the front, winds should shift from the north with steady CAA. Given ongoing CAA through daybreak Saturday, low temperatures are forecast to generally range from the mid 50s inland to around 60 along the coast. && .SHORT TERM /SATURDAY THROUGH MONDAY/... Saturday and Sunday: Broad troughing will prevail aloft through the weekend, with high pressure building in at the surface. With high pressure dominating at the surface, the weekend will feature a rather benign weather pattern. Temperatures on Saturday will actually be much cooler than the previous week, owing to FROPA on Friday night. Highs on Saturday are forecast to peak in the mid to upper 70s. Sunday will be slightly warmer, with highs in the low 80s. Sunshine will be plentiful, accompanied by a rain-free forecast. Monday: The upper level pattern shifts a tad on Monday, with models indicating a few shortwave troughs could ripple across the forecast area. This could provide enough forcing for isolated to scattered showers and thunderstorms. Temperatures are forecast to reach into the upper 70s to low 80s. && .LONG TERM /MONDAY NIGHT THROUGH THURSDAY/... Beginning Monday night the forecast turns more active as a warm front approaches the forecast area from the south. Aloft, a mid-level trough is forecast to swing through the southeastern states through Thursday. MOisture is expected to build into the region after the warm front lifts northward, with PWATs approaching 2". Several rounds of showers and thunderstorms are expected as the region remains well within the warm sector with plentiful moisture, aided from the approaching mid-level trough. Temperatures are expected to gradually warm through the period, with upper 70s to low 80s on Tuesday warming to the mid to upper 80s by Thursday. && .AVIATION /14Z FRIDAY THROUGH TUESDAY/... Prior to the 12Z TAFs, IR satellite indicated widespread debris clouds across the terminals. The main challenge will be the timing and intensity of MCS, located over southern AL and MS before 12Z TAFs. Based on the majority of the CAMs, the core of the MCS track along the FL/GA this morning. A band of showers and thunderstorms on the north side of the MCS is timed to pass over KSAV, expected between 13-17Z. The KSAV TAF will feature a mention of SHRA with VCTS between 13-17Z, with a TEMPO for TSRA from 14-17Z. KCHS and KJZI, the coverage TSRA will remain limited, the TAFs will feature TEMPOs for TSRA between 14-16Z. Late in the afternoon, a narrow band of showers and thunderstorms will develop along a cold front west of the terminals. After sunset, the coverage of showers and thunderstorms will decrease as the front approaches the terminals. The cold front is time to pass over the terminals between 3-4Z, turning winds from the NW at 10kts. Extended Aviation Outlook: VFR conditions will prevail through the weekend. Showers and thunderstorms could bring flight restrictions to the terminals Monday afternoon into the middle of next week. && .MARINE... A line of thunderstorm could push across the GA waters this mornings. These storms may yield wind gusts in excess of 35 kts, Special Marine Warnings may be issued. Otherwise, winds should remain from west-southwest between 15-20 kts. Wave heights are forecast to range between 3-4 ft. This evening, a cold front will approach from the northwest, timed to reach the coast around midnight. The front should rapidly sweep across the marine zones, turning winds from the north. Speeds will favor values between 15 to 20 kts, gusts could reach 25 kts at times. Seas will change very little overnight, remaining between 2-4 ft. Saturday through Wednesday: Generally tranquil marine conditions are forecast through the weekend as high pressure extends over the local forecast area. Winds will generally be around 10 knots, with seas averaging 1 to 2 feet. Monday night S to SE winds will surge slightly as a warm front lifts northward through the region, generally around 15 knots with some gusts around 20 knots. Seas will also increase, averaging 3 to 4 feet. These conditions will persist into the middle of the week. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$ NEAR TERM...BSH/NED SHORT TERM...CPM LONG TERM...CPM AVIATION...CPM/NED MARINE...CPM/NED