FXUS62 KCHS 271756 AFDCHS
Area Forecast Discussion National Weather Service Charleston SC Issued by National Weather Service Wilmington NC 1256 PM EST Tue Jan 27 2026
.WHAT HAS CHANGED...
The Aviation section was updated for the 18Z TAFs.
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.KEY MESSAGES...
- 1) Unseasonably cold weather will occur through early next
week.
- 2) Developing low pressure off the Southeast coast could bring
winter weather to the region this weekend.
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.DISCUSSION...
KEY MESSAGE 1...Unseasonably cold weather will occur through early next week.
As strong arctic high pressure (~1040 mb) continues to usher cold, dry air into the Southeast, temperatures are forecast to stay well below normal for an extended period of time. The ESAT NAEFS highlights this well with values ranging from -2 to -4 through Saturday, with values ranging from -4 to -6 on Sunday and Monday. There is fairly high model confidence, as the IQR shows a 2 to 3 spread in minimum temperatures from tonight through Friday, followed by increasing uncertainty Saturday through Monday with a wider 4 to 6 IQR spread.
Tonight: Expect minimum temperatures to drop into the low to mid 20s across the interior southeast South Carolina and southeast Georgia counties with upper 20s to low 30s along the coastline tonight. It's slightly warmer than the previous night, a signal well captured by the 12Z HREF and 13Z NBM, both indicating less than a 5% probability of apparent temperatures below 20 degrees. A Cold Weather Advisory does not seem warranted for tonight, and we have opted not to issue one.
The modest warming trend in temperatures, along with calm winds, should negate the need for Cold Weather Advisories tonight through Friday.
An impressive, strong arctic high (~1050 mb) will surge into the Southeast Friday night, ushering in another period of colder temperatures lasting into early next week. Itll be a very frigid weekend, with minimum wind chill values potentially reaching the single digits early Sunday morning, suggesting additional Cold Weather Advisories and possibly an Extreme Cold Warning may be warranted. A climate section has been added below to increase awareness of the unusually cold temperatures expected this weekend, a signal well represented by the 13Z NBM.
KEY MESSAGE 2:...Developing low pressure off the Southeast coast could bring winter weather to the region this weekend.
There remains good deterministic and ensemble model agreement that a sharp trough will drop southward out of the Great Lakes region Friday night with a deep closed low potentially dropping into GA and the Carolinas Saturday night. As this occurs aloft, a surface low is expected to develop off the Southeast coast on Saturday then lifting off to the northeast on Sunday. This could potentially produce a developing and expanding precipitation shield on the backside of the low that spreads across the forecast area across a time period including Saturday through Sunday morning.
While there is good model agreement regarding this general synoptic evolution, there remains considerable uncertainty in the details. One of the primary variables is just how far south the upper low digs which in turn will have significant implications concerning the surface low development offshore and its proximity to the coast. As of now, the GFS/GEM solutions are definitely further south with the upper low and produce a surface low track that is more favorable to greater coverage of precipitation across the forecast area. On the other hand, the EC isnt as far south with the upper low and yields a surface low that is further offshore and less conducive to precipitation. Also, given that even in the wetter GFS/GEM solution the forecast area is still on the periphery of the precipitation shield, it is hard to have anything other than low confidence regarding winter weather potential. One aspect that is a more high confidence is the robust agreement in the depth of arctic air across the area. Guidance advertises an uncommonly cold airmass and model soundings would support a pretty clean rain/snow precipitation type situation. There are also questions regarding the depth of moisture and potential extension into the dendritic growth zone aloft, further adding to the low confidence surrounding this potential winter weather event.
The forecast will continue to explicitly advertise rain/snow but it continues to be too early to attempt to nail down the likelihood, timing, extent, and magnitude of any snow accumulations.
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.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
27/18Z TAFs: VFR conditions should prevail through the 18Z TAF period.
Extended Aviation Outlook: Predominantly VFR through the extended period, with increasing potential for impacts Saturday associated with developing low pressure offshore of the Southeastern coast.
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.MARINE...
Tonight through Friday: Breezy northwesterly winds have gradually weakened since this morning, with speeds now ranging from 10 to 15 kts across the marine zones. A lingering northerly wind swell remains in the nearshore waters, but should quickly subside over the next few hours. A brief surge of west-northwest wind flow is possible on Wednesday night; however, conditions are expected to remain below Small Craft Advisory criteria. Otherwise, marine conditions remain generally quiet.
Confidence continues to increase that a significant marine event will impact the local waters this weekend. A strong blast of arctic air will begin Friday night as high pressure builds in from the northwest and a low pressure system develops just offshore. This strong cold advection combined with a tightening pressure gradient associated with the surface low will produce increasing winds and seas across the local waters. Small Craft Advisories appear to be a near certainty with this event, and there is also an increasing probability of widespread gales as well. While details remain a bit uncertain, conditions are expected to ramp up Friday night then peak in the Saturday through Saturday night time period. The surface low should pull away from the area through Sunday, but overall conditions will remain hazardous across the local waters.
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.CLIMATE...
Record Low Temperatures:
January 31: KCHS: 15/1966 KCXM: 19/1966 KSAV: 16/1966
February 1: KCHS: 21/1977 KCXM: 23/1900 KSAV: 23/1977
February 2: KCHS: 19/1980 KCXM: 17/1917 KSAV: 18/1917
Record Low Maximum Temperatures:
January 31: KCHS: 36/1948 KCXM: 34/1936 KSAV: 37/1909
February 1: KCHS: 38/1980 KCXM: 36/1900 KSAV: 38/1900
February 2: KCHS: 38/1980 KCXM: 38/1898 KSAV: 38/1951
Record Snowfall:
January 31: KCHS: 0.6/1977 KSAV: 1.3/1977
February 1: KCHS: Record not established. KSAV: Record not established.
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.EQUIPMENT...
The KCLX radar remains out of service. Critical parts are on order and are now scheduled to arrive Wednesday. Users should use adjacent WSR-88D sites, including KCAE, KLTX, KJAX, KVAX and KJGX.
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.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None. SC...None. MARINE...None.
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KEY MESSAGES...CHS DISCUSSION...CHS AVIATION...CHS MARINE...CHS