FXUS62 KCHS 091759 AFDCHS
Area Forecast Discussion National Weather Service Charleston SC 1259 PM EST Sun Nov 9 2025
...NEAR RECORD COLD AND A WIDESPREAD FREEZE MONDAY NIGHT WITH
WIND CHILLS DROPPING INTO THE UPPER TEENS TO MID 20S -- FREEZE WARNING ISSUED...
.SYNOPSIS...
A strong cold front will move through tonight, bringing much colder conditions to the area this week. High pressure will build into the region through the remainder of the week.
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.NEAR TERM /THROUGH TONIGHT/...
This Afternoon: The overall forecast thinking has not changed since the update this morning. Near term guidance coupled with the 09/12z HREF continues to show a more consolidated signal for a local enhancement of showers/tstms across the coastal corridor from late this afternoon into this evening ahead of the strong cold front. Model cross sections show a corridor of strong UVVs between 850-500 hPa during this time, likely in response to the approach of 700 hPa shortwave and associated speed max over the Midlands. Although instability looks only marginally favorable given the time of day, the lack of instability could be overcome by increasing quasi-geostropic forcing ahead of the shortwave. Pops were increased further to 60% across the coastal corridor to help trend the forecast, but this is still somewhat lower than some guidance would suggest. Further adjustments may be needed as trends become a bit more apparent.
Strong wind fields and lower temperatures aloft suggest there will be a risk for large hail and damaging winds, but the absence of strong instability suggests the severe weather risk will likely remain somewhat isolated. However, wind fields are supportive of supercells, especially if localized corridors of higher instability can be realized. The severe weather risk looks highest between 5-10PM.
Overnight: The surface cold front is poised to push offshore by mid-evening with the onset of stronger post-frontal cold air advection occurring with the passage of the 850 hPa front a few hours after that. The bulk of the shower/tstm activity will push offshore with the surface front, but a broken line of showers could swing through along the 850 hPa front itself. Near term pops were adjusted slightly to better reflect this idea. Gusty northwest winds will prevail through the daybreak owing to strong cold air advection. 850 hPa temperatures will drop from +10 to +12C to 0 to +5C by daybreak Monday as skies steadily clear. Lows will range from the upper 30s across far interior Southeast Georgia to mid-upper 40s across Charleston County and along the immediate Georgia and far lower South Carolina coast.
Lake Winds: Winds on Lake Moultrie are expected to increase to 15-20 kt overnight with the onset of strong cold air advection behind a cold front. Gusts could approach 25 kt at times, but durations are uncertain. NBM/HREF wind gust probabilities for gusts 25 kt or greater are quite low, so a Lake Wind Advisory was not issued for the overnight period. Trends will be carefully monitored.
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.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
A strong cold air advection regime will set up on Monday as high pressure builds in at the surface behind the departing cold front and an anomalously deep mid-level trough dominates aloft. Monday's high temperatures are forecast to only reach into the low to mid 50s, which despite plentiful sunshine, will likely feel a tad cooler due to the gusty NW winds. Gusty NW winds are forecast to develop across the region Monday afternoon, generally in the 20 to 25 mph range. A Lake Wind Advisory has been issued for Lake Moultrie from Monday afternoon into early Tuesday morning. The main forecast highlight will be Monday night as temperatures plummet into the low 20s inland, with freezing temperatures likely almost to the beaches. these low temperatures will challenge the record low temperatures at all three climate sites - see Climate section for more details. A Freeze Warning has been issued for the entire forecast area as confidence remains high in a widespread freeze occurring Monday night. Additionally, breezy conditions overnight and into Tuesday morning will yield wind chill values in the upper teens to around 20, especially across inland zones. A Cold Weather Advisory may be required for a portion of the forecast area, mainly west of I-95.
Not much change in the synoptic set up on Tuesday, with CAA still dominating due to the anomalously deep mid-level trough. High temperatures on Tuesday will likely struggle to get out of the low 50s, with some locations maybe not making it out of the 40s. The gusty NW winds seen on Monday will diminish to only around 15 mph Tuesday afternoon. Another chilly night is expected Tuesday night, as winds continue to diminish and skies remain clear. A very nice radiational cooling set up is forecast, yielding low temperatures in the upper 20s inland and upper 30s to near 40 along the coastline.
The mid-level trough will push off the Eastern Seaboard overnight Tuesday into Wednesday, transitioning into a zonal flow aloft on Wednesday. At the surface the center of high pressure will be over the southeastern states. Temperatures will reach back up into the mid 60s, though still a tick below November normals. A rain free forecast has been maintained as high pressure dominates.
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.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
Zonal flow will dominate aloft mid-week, with broad ridging developing late week. At the surface high pressure will prevail, yielding a dry forecast through the period. Temperatures will return to near normal on Thursday and are forecast to remain near normal into the weekend.
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.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
09/18z TAF Discussion: KCHS/KJZI/KSAV: The risk for tstm impacts will increase by late afternoon and continue through mid-evening before a cold front shifts offshore. Risk looks greatest 00-03z at KCHS and KJZI and 23-02z at KSAV. Some showers will likely linger after this until FROPA by late evening/very early Monday morning. Gusty northwest winds will prevail after FROPA and persist into 18z Monday.
Extended Aviation Outlook: Gusty NW winds 20 to 25 kt are forecast Monday afternoon into Monday evening. Otherwise, prevailing VFR.
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.MARINE...
Tonight: Southwest winds will turn west and eventually northwest later this evening and overnight a strong cold front pushes through the coastal waters. Winds are expected to surge to 20-25 kt behind the front with 15-20 kt in the Charleston Harbor as cold air advection intensifies. Small Craft Advisories have been extended north in the South Santee-Edisto Beach nearshore leg and are now in effect for all areas overnight with the exception of Charleston Harbor. Gusts could get close to 25 kt in the Charleston Harbor after midnight, especially near the Harbor entrance where the fetch will be the longest, but it is unclear if durations will be enough to support a Small Craft Advisory. Seas will build to 3-4 ft nearshore waters away from the beaches to 4-6 ft over the Georgia offshore waters.
Monday through Thursday: In the wake of a strong cold front gusty NW winds will develop across the marine zones as high pressure builds into the region. A Gale Watch is in effect for all waters outside of the Charleston Harbor, where a Small Craft Advisory is in place. Wind gusts around 35 knots are forecast Monday afternoon into early Tuesday morning (25 knots in the Charleston Harbor). Seas are forecast to build, peaking Monday night around 4 to 6 ft in the nearshore waters and 7 to 9 ft in the 20 to 60 nm offshore GA waters. The center of high pressure meanders closer to the local waters mid-week, with winds diminishing to 10 to 15 knots on Tuesday and seas averaging 1 to 3 ft. The remainder of the period is forecast to remain below Small Craft Advisory criteria.
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.FIRE WEATHER...
Some fire weather concerns exist for both Monday and Tuesday as RH values drop to around 30% on Monday and 25% on Tuesday. Additionally, NW wind gusts on Monday are forecast to be around 20 to 25 mph, with gusts to around 15 mph on Tuesday. Some beneficial rainfall is possible Sunday afternoon which would help alleviate some concerns. At this time, partners indicate fuels are not dry enough for an elevated fire danger at this time.
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.CLIMATE...
Monday night's freeze will not be the earliest on record for all three climate sites. Below are the records for informational purposes.
KCHS: October 25, 1937 KCXM: November 3, 1954 KSAV: October 27, 1962
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
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.CHS WATCHES/WARNINGS/ADVISORIES...
GA...Freeze Warning from 9 PM Monday to 9 AM EST Tuesday for GAZ087-
088-099>101-114>119-137>141.
SC...Freeze Warning from 9 PM Monday to 9 AM EST Tuesday for SCZ040-
042>045-047>052. Lake Wind Advisory from 5 PM Monday to 4 AM EST Tuesday for SCZ045.
MARINE...Small Craft Advisory from 3 PM Monday to 7 AM EST Tuesday for
AMZ330. Small Craft Advisory from midnight tonight to 4 PM EST Monday for AMZ350-352-354. Gale Watch from Monday afternoon through late Monday night for AMZ350-352-354-374. Small Craft Advisory from 9 PM this evening to 4 PM EST Monday for AMZ374.
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