Area Forecast Discussion
Issued by NWS Charleston, SC
Issued by NWS Charleston, SC
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634 FXUS62 KCHS 081343 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 843 AM EST Sat Nov 8 2025 .SYNOPSIS... High pressure will extend across the region through the weekend. A strong cold front will cross the region by Sunday night bringing much colder conditions to the area next week. && .NEAR TERM /THROUGH TONIGHT/... UPDATE: KCLX shows showers breaking out south of I-16 this morning with weak warm air advection/isentropic ascent ongoing. Activity should increase a bit later this afternoon ahead of a 850-700 hPa shortwave that is currently propagating across the Deep South. Modified RAP soundings yield moderate levels of instability with SBCAPE 1500-2000 J/kg with in a moderately sheared environment featuring 0-6km bulk shear values around 40 kt. Although mid-level lapse rates will remain fairly muted, a few strong tstms can not be ruled out later this morning and especially this afternoon as surface temperatures rise and low- level lapse rates increase. Gusty winds and small hail are the most likely hazards. The risk for tstms reaching severe levels remains low given the less than ideal mid-level lapse rates. Near term pops were adjusted slightly to reflect current radar and short term model trends. Out ahead of an approaching cold front, weak positive theta-e advection in the mid-levels is resulting in scattered to broken cloud coverage, with winds remaining just mixy enough to keep overnight lows in the mid 50s inland into the lower 60s along the coast. Along the cold front, scattered to areas of showers and isolated thunderstorms are occurring, though model consensus remains on the lower end of what exactly the rainfall coverage will look like as the front stalls to our northwest. Despite the weak positive theta-e advection continuing along with some instability, the NBM only gave slight chances for the showers/storms to continue into the late morning hours, primarily for far southeast Georgia. Convection allowing models would suggest the probabilities for rain would extend into portions of southeast South Carolina as well, so given the similar environment continuing did extend the coverage of showers in both space and time much further north into South Carolina. While we`ll likely see a break in rain coverage, convection allowing models have noticeably increased the chances for showers and isolated thunderstorms throughout the morning and into the afternoon hours. This is due to continued modest lift from the positive theta-e advection, decent instability of 750-1500 J/kg, high shear of up to 50 knots, and k-index values in the mid-30s. SPC noted a similar trend, and even introduced a level 1 out of 5 (Marginal) risk for severe thunderstorms across inland southeast South Carolina and southeast Georgia. Given the lack of pops from the NBM, went ahead and increased chances for showers and thunderstorms to 30% to account for the possibility of thunderstorms, with a low probability for severe thunderstorms. Given the warm-air advection and breezy southwesterly winds, afternoon high temperatures still look to peak into the lower 80s across southeast Georgia and upper 70s in southeast South Carolina, while those along the coast will stay in the mid 70s. Into the early overnight hours, expect another round of light scattered showers and isolated thunderstorms, primarily limited to inland areas. As a strong cold front approaches from the west- northwest, the surface pressure gradient increases, and will keep winds on the semi-breezy side. This will also keep temperatures on the warmer side, with overnight lows in the lower to mid 60s, warmest along the coast. && .SHORT TERM /SUNDAY THROUGH TUESDAY/... Sunday: A deep 525DM closed low will dive across the Great Lakes region through the day. The longwave trough will extend south to the Gulf, with the axis remaining to the west. At the sfc, a deepening low pressure system will track across the Ohio River Valley during the morning, reaching PA/NY by the afternoon. A strong cold front will sweep across the Southeast U.S. during the daylight hours, timed to reach SE GA and SC Lowcountry during the late afternoon to early evening hours. The late arrival of the front should allow high temperatures to range around 80 across the SC Lowcountry to the low 80s across SE GA. Forecast soundings indicate a significant inversion will remain around h75 through much of the day. However, by the late afternoon, the inversion should weaken as the cold front approaches from the west, CAPE values may range between 500-800 J/kg. Shear should increase along and ahead of the cold front, with 6km bulk shear reaching around 55 kts by sunset. ML/AI guidance indicates that the region may see the potential for 15-30 percent of severe weather with 25 nm of any given point. SPC current highlights the region with a marginal risk for severe thunderstorms. The cold front will push offshore late Sunday evening, with strong CAA expected across the forecast area through the rest of the night. In fact, NAM12 indicates that H85 temps fall below 0C for portions of inland GA and SC. Low temperatures Monday morning are forecast to range from the upper 30s across inland GA to the mid 40s along the coast. On Monday, GFS indicates that 12Z H85 temps along a line from KSAV to KCHS will range around 4C. H85 temperatures should fall through the day, falling to around -4C by sunset. Temperatures will struggle to warm with the ongoing strong CAA, despite the full sun. High temperatures should remain around 15 degrees below normal, highs generally in the mid 50s. The surge of CAA may lead to gusty winds across the region, possibly reaching Lake Wind Advisory criteria during the late afternoon. Monday night, the H5 trough should ripple over across the forecast area during the overnight hours. The center of 1030 mb high should remain over Deep South, maintaining a 2 mb pressure gradient. The combination of lingering cold llvl thicknesses and clear sky should allow temperatures to steady cool through the night. Using a blend of guidance, low temperatures are forecast to range in the 20s along and west of I-95, values in the low 30s to the east. Only areas along the immediate coast area forecast to remain above freezing by daybreak Tuesday morning. These temperatures will challenge record low values, see Climate section below. In addition, wind speeds should generally remain between 5 to 10 mph, yielding wind chill values in the low to mid 20s, some pockets in the upper teens are possible. The forecast hard freeze should end the growing season for the majority of the forecast area. There is also a chance that a Cold Weather Advisory could be needed for a few areas. Tuesday, the center of high pressure sourced from central Canada will push over the forecast area. High temperatures are forecast to remain around 20 degrees below normal, generally in the low to mid 50s. In fact, we could see a new record low max at KCHS, see Climate section below. In addition, dewpoints may favor values in the teens across SE GA to around 20 across the SC Lowcountry during the afternoon. Afternoon RH values may fall into the low to mid 20s across SE GA to around 30 percent across the Lowcountry. Fortunately, the weak pressure gradient should keep wind speeds between 5 to 10 mph. && .LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/... Tuesday night, clear sky with light to calm winds should provide strong radiational cooling conditions through the night. Low temperatures should fall to around 30 degrees along and west of I- 95, with mid to upper 30s to the east. Temperatures should trend warmer through the rest of the work week. In fact, temperatures should return to mid November normals by Thursday, remaining near normal through the rest of the forecast period. Conditions should remain dry under dry NW mid-level flow. && .AVIATION /13Z SATURDAY THROUGH WEDNESDAY/... 08/12z: VFR through the day at all TAF sites. Areas in inland southeast Georgia may see some MVFR cigs throughout the morning hours, but not expected to reach the SAV terminal. Isolated to scattered showers and thunderstorms may form later this morning into the afternoon hours, have included PROB30s at SAV and CHS as they are not expected to be prevailing at this time. Late overnight into Sunday, an MVFR to IFR stratus deck may be pushing into the region from eastern Georgia. Extended Aviation Outlook: Prevailing VFR into the weekend. Isolated showers or thunderstorms could impact the terminals on Sunday afternoon, possibly bringing brief flight restrictions. Gusty NW winds around 20 knots will develop Monday, diminishing into Tuesday. && .MARINE... Through Tonight: Winds will become more uniformly southerly later this afternoon into tonight as high pressure shifts farther offshore and a cold front approaches from the west and northwest. Speeds will generally remain 10 kt or less, but will increase closer to 10-15 kt as daybreak approaches. Seas will average 4 ft or less through the overnight hours. Sunday through Wednesday: A strong cold front will approach the marine zones on Sunday. Return flow ahead of the front should yield southwest winds between 10 to 15 kts, some gusts to 20 kts possible. Seas are forecast to range between 2 to 4 ft. A strong cold front will sweep across the region Sunday night into Monday. In the wake of the front, winds should turn from the northwest and strengthen to 20 to 25 kts, with gusts near 30 kts. Seas will build Sunday night through Monday, reach 3 to 5 ft across the nearshore with 6 ft seas across the outer GA waters. Monday night, a surge of CAA will push across the Atlantic waters. Northwest winds may increase above 25 kts with gusts into the low 30s across the Atlantic waters. Speeds appear close to Gale force Monday evening outside the CHS Harbor, with Small Craft conditions across the harbor. Seas should peak Monday night, ranging between 4 to 8 ft. Small Craft Advisories are likely for all waters, with a Gale Watch/Warning not out of the question for a portion of the waters. Conditions should improve on Tuesday and Wednesday as high pressure settles over the area. && .CLIMATE... Upcoming Record Low Temperatures: November 11 (Tuesday): KCHS: 29/1943 KCXM: 32/1913 KSAV: 31/1968 November 12 (Wednesday): KCHS: 27/1943 KCXM: 33/1894 KSAV: 30/2011 Upcoming Record Low Maximum Temperatures: November 10 (Monday): KCHS: 46/1991 KCXM: 47/1991 KSAV: 49/1968 November 11 (Tuesday): KCHS: 54/1968 KCXM: 46/1913 KSAV: 49/1913 && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$