Area Forecast Discussion
Issued by NWS Charleston, SC
Issued by NWS Charleston, SC
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398 FXUS62 KCHS 102210 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 610 PM EDT Fri May 10 2024 .SYNOPSIS... A cold front will push through the area tonight. 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 /UNTIL 6 AM SATURDAY MORNING/... Convection upstream continues to occur thanks to MLCAPE of 1000-1500 J/kg and 0-6 km Bulk Shear around 50 knots. The trend will be for it to congeal into clusters or even a broken line as it shifts southeast toward and eventually into our region this evening. The forecast has been adjusted to account for this, now showing as much as scattered coverage moving into Berkeley County by 8 pm, into much of the Charleston, Dorchester, and Colleton by 9 pm, then into Beaufort and Jasper by 10 pm. Isolated coverage will also happen further west during the evening, but taking until around 10 pm to reach Chatham County. Given DCAPE in excess of 1000 J/kg, there certainly will be some potential for strong or maybe even severe winds. Since there has been several reports of large hail upstream, it does remain a possibility for it to reach parts of our area too. Although the wind potential seems better Also, the warn on Forecast does have as much as a 20-25% probability of severe winds reaching Berkeley County. Nothing widespread, but we will continue to mention this potential in the Hazardous Weather Outlook. The overnight period continues to look to be rainfree. No changes to low temperatures. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/... Saturday and Sunday: A stout northwest flow will dominate aloft as surface high pressure builds in from the west. Quiet, dry conditions will prevail with forecast soundings showing modest capping aloft with low net moisture values (PWATs <1"). A modest west/northwest flow atop the boundary layer should delay/pin the afternoon resultant sea breeze both afternoons. Low-level thickness values support highs in the upper 70s/near 80 on Saturday warming into the lower 80s on Sunday. Lows Saturday night will drop into the mid- upper 50s inland with mid 60s at the beaches with upper 50s/lower 60s inland and upper 60s/near 70 at the beaches Sunday night. Monday: A warm front will begin to organize to the south and move north into the area as a storm system develops to the west. Isolated to scattered showers/tstms could develop near this feature in the afternoon, but the bulk of anything meaningful looks to remain south of the Altamaha River. Forecast soundings north of the warm front are not overly unstable with meager MLCAPE, positive LI`s with K- indices <30C noted, so conditions do not look overly favorable for deep convection despite highs warming into the upper 70s/lower 80s. Pops 20-30% look reasonable during this time with any mention of thunder being confined to mainly Southeast Georgia due to some uncertainty on location/timing of the developing warm front. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... Monday Night and Tuesday: Rain chances will increase Monday night into Tuesday as a warm front lifts north and the region becomes fully embedded within the warm sector of an approaching storm system. Modest forcing for ascent ahead of a number of southern stream impulses embedded ahead of a shortwave that digs across the Tennessee and Ohio Valleys will steadily increase within an increasingly moist environment. There are a few model signals that a large convective complex along the northeast Gulf coast/Florida Panhandle could disrupt moisture transport into the area which could limit the amount of convection over Southeast South Carolina and Southeast Georgia Tuesday. These trends will have to be watched carefully. For now, a blend of the NBM with the drier SuperBlend consensus was used to construct pops. Pops 60-70% were highlighted for Monday night with 80% pops for Tuesday. Lows Monday night will range from the lower 60s well inland to the lower 70s at the beaches. Highs Tuesday will warm into the upper 70s/lower 80s, limited by extensive cloud cover and showers/tstms. Wednesday and Thursday: Overall, rain chances will be lower for Wednesday into Thursday, but some degree of convection can be expected as a series of weak fronts/troughs move through the Southeast States. Chance pops were highlighted during this time. Temperatures will be near to slightly above normal for both days. && .AVIATION /22Z FRIDAY THROUGH WEDNESDAY/... VFR conditions should prevail at KCHS, KJZI, and KSAV through 18z Saturday. The main forecast challenge will be the potential for isolated to scattered showers and thunderstorms late this afternoon and early this evening, primarily near KCHS and KJZI. We have added in a few hours of VCSH as the confidence of direct impacts at KCHS and KJZI remains low. A thunderstorm will be possible too, but chances aren`t high enough to include a mention of TSRA. Whatever activity does develop will shift offshore in the evening and the rest of the period will be dry. Skies will clear out overnight as well. Winds will turn northwesterly and then northerly overnight. Extended Aviation Outlook: Showers and thunderstorms could bring flight restrictions to the terminals Monday afternoon into the middle of next week. && .MARINE... Tonight: Mariners can expect some of those t-storms upstream to make it into the northern waters by 8-9 pm, then into the southern South Carolina waters an hour or so later, and finally into the Georgia waters before midnight. A few of these storms could result in strong winds in excess of 35 kt, along with frequent lightning strikes. Marine Weather Statements and/or Special marine Warnings are possible. Elevated west-southwest flow will continue this evening, with a solid 15-20 knots and a few isolated gusts up to around 25 knots. An inland cold front will shift offshore by the early morning hours and winds will turn northwesterly and eventually northerly. Wind speeds will remain elevated into the 15-20 knot range. A few gusts up to around 25 knots will be possible, but we have opted to not issue any Small Craft Advisories at this time as winds should remain below criteria most of the time. Seas are forecast to average 2-4 feet through the night. Saturday through Wednesday: There are no concerns through Monday. The risk for Small Craft Advisory conditions will increase Monday night into Tuesday as a warm front lifts north and storm system approaches from the west. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$ NEAR TERM... SHORT TERM... LONG TERM... AVIATION...BSH MARINE...