FXUS62 KCHS 131814 AFDCHS
Area Forecast Discussion National Weather Service Charleston SC 214 PM EDT Sun Oct 13 2024
.SYNOPSIS...
High pressure will prevail tonight. A strong cold front will push through the area later Monday, followed by cool and dry high pressure through late week.
&&
.NEAR TERM /THROUGH TONIGHT/...
This Afternoon: Aloft, a sheared mid-lvl shortwave will move across Florida and the southwestern Atlantic while an amplifying trough shifts across The Great Lakes region. At the sfc, a weak coastal trough will shift farther east across the Atlantic and away from the region while high pressure remains the dominant weather feature across Southeast South Carolina and Southeast Georgia. Dry air, large-scale subsidence and lack of forcing will result in another sunny day. Warm air advection along with a westerly synoptic flow will allow for a warmer day than yesterday. 1000-850 mb thickness values suggest high temps ranging in upper 70s near the coast to lower 80s inland.
Tonight: A cold front associated with the mid-upper trough well to the northwest will edge closer to the region, but will remain upstream through the night. Mid-lvl shortwave energy will also continue passing just south of the local area, but moisture is lacking so this feature will have no effect on weather conditions. Meanwhile, a low-lvl jet will move in the vicinity along with higher dew points, preventing cooler temps as observed during the past 3 nights. On average, lows will be in the upper 50s and lower 60s, with mid-upper 60s near and along the ocean.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
Warm and dry conditions will persist on Monday ahead of an approaching cold front, which is poised to cross the area later in the day into the evening. Highs are forecast to reach the mid to even upper 80s in spots under full sunshine. It will be cooler on Tuesday following frontal passage, with temperatures averaging in the mid 70s. Lows Tuesday night will mainly be in the upper 40s to lower 50s.
A mid level trough will dig across the eastern CONUS Tuesday night into Wednesday before pushing offshore, allowing a reinforcing cold front to cross the area. Highs on Wednesday are expected to only top out in the mid to perhaps upper 60s, which is some 10-15 degrees below climo.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
Surface high pressure initially over the Ohio Valley will shift east into the Northeast and mid-Atlantic through late week and continue extend into the local area. Models indicate a coastal trough could develop late in the period/over the weekend, but any showers associated with it should stay offshore so the forecast remains rain- free. Temperatures will remain cooler than normal but will moderate with time.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
VFR conditions will prevail at KCHS/KJZI/KSAV through 18Z Monday. West winds could gust to 15-20 kt at all terminals Monday afternoon.
Extended Aviation Outlook: VFR.
&&
.MARINE...
This Afternoon: A weak coastal trough will continue east, shifting farther away from local waters and allowing high pressure to dominate the pattern for the day. In general, west winds around 10 kt or less should turn southwest, mainly across nearshore waters due to weak sea breeze influences along the coast. Seas will rand between 2-4 ft, largest across offshore Georgia waters.
Tonight: The cold front crosses the Appalachians late, overtaking the surface trough out ahead of it. There's some tightening to the pressure gradient, and that along with stronger low level winds moving in will produce gusty SW winds as high as 15 kt for most waters, and potentially up to 20 kt across northern South Carolina waters off the Charleston County coast. Seas will average 3-4 ft, although some 5 footers will move into the Charleston County Atlantic waters after midnight with the increase in winds.
Monday through Friday: Southwest winds on Monday will turn northwest and north for Tuesday following passage of a cold front. A secondary, reinforcing cold front is expected to arrive Tuesday night with strong high pressure to build in its wake. Winds and seas will increase as a result, and Small Craft Advisories will likely be needed for portions of the waters late Tuesday night into Wednesday. Conditions should improve somewhat for Thursday but will likely increase again on Friday as a coastal trough develops. Northeast winds could again approach or exceed 25 knots with seas building to 4-7 feet so additional advisories will be possible.
Rip Currents: There remains enough swell energy to go with a Moderate Risk of Rip Currents at all beaches today.
&&
.TIDES/COASTAL FLOODING...
The threat for coastal flooding will increase this week due to the upcoming full moon and perigee. The time period of greatest concern is mid to late week when astronomical tides are highest and winds are more favorable. At least minor coastal flooding is possible, and Coastal Flood Advisories could be needed along the entire southeast South Carolina and southeast Georgia coast.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None. SC...None. MARINE...None.
&&
$$
NEAR TERM...DPB SHORT TERM... LONG TERM...DPB AVIATION... MARINE...DPB