Area Forecast Discussion
Issued by NWS Charleston, SC

Current Version |  Previous Version |  Text Only |  Print | Product List |  Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
726 FXUS62 KCHS 280408 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 1208 AM EDT Tue May 28 2024 .SYNOPSIS... A cold front will move into the region tonight, then stall nearby through the middle of the week. High pressure will return for the second half of this week. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
-- Changed Discussion --
Warm/moist conditions remain in place early this morning. Regional radars show isolated showers trying to percolate across east-central Georgia into interior Southeast Georgia with the approach of a weak mid-level perturbation. This activity is developing within an enhanced 850 hPa theta-e ridge axis that stretches from Jefferson and Dublin, GA east to near the Charleston Metro Area. Despite the onset of nocturnal cooling, RAP soundings show quite a bit of elevated CAPE (1500-2000 J/kg) in place above the shallow noctural inversion. If isolated convection can begin to tap into this instability, then an uptick in showers/tstms could occur over the next few hours. This is implied by both the H3R and RAP which shows activity developing during the early morning hours across Southeast Georgia into south coastal South Carolina. With meaningful DCAPE still in place and freezing levels below 14 kft, there is still a risk for an isolated strong to severe tstm through daybreak. This is certainly somewhat that will have to be watched over the next few hours. 20% pops were introduced with activity expected to shift to the lower South Carolina coast as sunrise approaches. Lows will range from around 70 well inland to the mid 70s at the beaches and Downtown Charleston.
-- End Changed Discussion --
&& .SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/... Tuesday: The mid-levels will consist of a longwave trough over the eastern half of the U.S. At the surface, a cold front will be located along our coast early in the morning. It`s forecasted to transition into a stationary front shortly thereafter and meander along our coast through the early evening. By late evening, it`ll transition back into a cold front and move further offshore, and away from our area. Broad High pressure will be centered over the Northern Plains overnight, with its periphery building into our region. The highest moisture values will remain just offshore, on the other side of the front. With less moisture in place, there won`t be much instability in place across our area, despite temperatures peaking in the lower 90s away from the beaches. The synoptic models and long-range CAMs hint at maybe an isolated shower or thunderstorm, mainly near are coastal SC counties in the afternoon. Further south, more dry air and capping should limit any convection from developing. Anything that does manage to develop over our SC counties should be weak, dissipating by sunset. The evening and overnight will be dry everywhere. Lows will range from the lower 60s far inland to around 70 degrees at the beaches. Wednesday and Thursday: The mid-levels will consist of a longwave trough over the eastern half of the U.S. Wednesday. The trough will become more amplified along the East Coast Wednesday night into Thursday, in response to ridging approaching from the west. At the surface, broad High pressure centered over the Northern MS Valley Wednesday morning will shift to the Great Lakes region by late Thursday. The periphery of this High will reach all the way into the Southeast U.S. both days, bringing dry conditions. Afternoon dew points may fall into the 50s away from the beaches, which will make it feel very comfortable. Temperatures on Wednesday should peak around 90 degrees, and the lower to mid 80s on Thursday. No convection is expected either day, but fair weather cumulus is expected both afternoons. Lows Wednesday night will range from the lower 60s far inland to around 70 degrees at the beaches. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... A trough over the East Coast Thursday night will shift offshore by later Friday, followed by a ridge building on Saturday, and possibly prevailing into Monday. High pressure will be the dominant surface feature during the long term. POPs will be around 20% each afternoon with temperatures a few degrees below normal. && .AVIATION /04Z TUESDAY THROUGH SATURDAY/...
-- Changed Discussion --
28/06z TAF Discussion: KCHS/KJZI/KSAV: VFR through 29/06z. There is a risk for some isolated tstms forming near KCHS and KJZI as daybreak approaches. May need to include VCTS overnight as confidence increases in this activity passing by both terminals. Extended Aviation Outlook: VFR.
-- End Changed Discussion --
&& .MARINE...
-- Changed Discussion --
Tonight: Southerly winds 10-15 kt with seas 2-3 ft will prevail. Tuesday through Saturday: Rather tranquil conditions are expected. A cold front will be located along our coast early Tuesday morning, moving further offshore, and away from our area Tuesday night. High pressure will then gradually move towards our area midweek and prevail through the weekend. Even the sea/land breezes don`t appear to be too strong during this time period. Wind speeds should average 15 kts or less. Seas will be 4 ft or less.
-- End Changed Discussion --
&& .CLIMATE... Record High Minimum Temperatures: May 27: KCHS: 76/1991 KCXM: 79/2019 KSAV: 77/1878 && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$