AFD_CHS

FXUS62 KCHS 161758 AFDCHS

Area Forecast Discussion National Weather Service Charleston SC 1258 PM EST Fri Jan 16 2026

...THERE IS A CONTINUED RISK FOR SOME WINTRY WEATHER LATE

SATURDAY NIGHT INTO SUNDAY...

.WHAT HAS CHANGED...

Details on wintry weather Saturday night into Sunday have been update and include a reasonable worse case scenario for Key Message 2. Added Wednesday morning to key message 3.

.KEY MESSAGES...

- 1) Dry conditions and low relative humidity values are

expected this afternoon.

- 2) Potential for a rain/snow mix Saturday night into Sunday as

a coastal low develops over the Atlantic.

- 3) Cold temperatures in the low to mid 20s (upper 20s along

the coast) possible Monday, Tuesday, and Wednesday morning.

.DISCUSSION...

KEY MESSAGE 1: Dry conditions and low relative humidity values are expected this afternoon.

The center of the dry air mass will slide across SE GA and the SC Lowcountry today. Dewpoints could be as low as the single digits along and west of I-95, to the west, dewpoints between 10 to 15 degrees should be common. As temperatures warm to around 50 degrees this afternoon, RH values may range from the upper teens to around 20 percent west of I-95, to the mid to upper 20s to the east. Fortunately, the weak pressure gradient should only support winds around 10 mph. No Fire Danger Statement planned for today. However, low relative humidity was headlined in the Fire Weather Forecast.

KEY MESSAGE 2: Potential for a rain/snow mix Saturday night into Sunday as a coastal low develops over the Atlantic.

An impressive upper trough is forecast to dig across the eastern CONUS Sunday which will drive a strong cold front offshore and spark cyclogenesis off the Southeast U.S. coast and Mid-Atlantic--a classic Miller-A scenario. Widespread rain will spread into the area Saturday night into Sunday then gradually wind down Sunday afternoon as a colder/drier airmass filters into the region. As cold air advection (CAA) commences post FROPA Sunday morning, temperatures aloft will steadily cool with time with thermal profiles becoming increasingly favorable for rain mixing with and possibly changing to all snow as precipitation exits the area. As is typically the case in Miller-A cyclogenesis regimes, the colder/drier air will likely be chasing the departing precipitation area which only open up a brief window (several hours) for possible p-type issues Sunday morning, possibly lingering into the early the afternoon hours. Model soundings at 12-15z Sunday suggest interior Southeast Georgia will favor the best overlap of lingering precipitation with thermal profiles supportive of snow with soundings at KAQX, KMHP and KRVJ all showing cloud temperatures of at least -20C (sufficient for ice nucleation) with sub-freezing profiles all the way down to just above the boundary layer. Farther to the east of this corridor, however, thermal profiles become increasingly less favorable with lower probabilities for ice nucleation in the cloud (drier/warmer cloud temperatures) with a deeper surface-based melting layer.

The most likely scenario at this time favors rain spreading to the area Saturday night, then beginning to transition to a rain/snow mix across far interior Southeast Georgia up into Allendale County, SC after daybreak Sunday and possibly ending as a brief period of all snow or a rain/snow mix during the mid-morning hours before ending. The rain/snow mix could reach as far east as the I-95 corridor with all rain favored along the coast. Ground temperatures should remain too warm for significant accumulations. One alternative solution, which must be carefully monitored, is the potential development of embedded convective elements or bands which may support corridors of heavier snowfall where thermal profiles and UVV profiles become locally augmented. Some guidance suggest favorable alignment of bands of intense 850-700 hPa frontogenesis with pockets of negative EPV which can favor the genesis of convective elements or bands. Although ground temperatures are likely to remain rather warm, localized, heavier snowfall rates could easily support a quick dusting to possibly as high as 0.5" before a quick melting occurs should these convective structures form. NBM snow probabilities for 1" are running high as 20-30% across parts of interior Southeast Georgia (closer to the 16/00z EC Ensemble footprint) and may very well be picking up on this convective potential. While this looks scenario looks unlikely right now given the overall snowfall probabilities, it is a reasonable worse case scenario and should be considered for planning purposes.

As for impacts, winter weather impacts from this system still look to remain on the low side. The latest probabilistic Winter Storm Severity Index (WSSI-P) continues to advertise a 15-25% chance of minor impacts, so again, folks should still exercise extra caution if travel is necessary as a few slick spots could occur. Again, should those corridors of heavier snowfall develop, then some higher level impacts may evolve, mostly for travel. A low-end risk for some patchy black ice may linger into Sunday night, but lingering winds and lowering dewpoint should help dry roads out prior to the onset of freezing temperatures Sunday night.

KEY MESSAGE 3: Cold temperatures in the low to mid 20s (upper 20s along the coast) possible Monday, Tuesday, and Wednesday morning.

Weak High pressure will be across the southern MS Valley Monday morning, with a much stronger High over the Northern Plains. The Northern Plains High will move to the southeast on Monday and become the dominant High. It should move over the Southeast U.S. Tuesday night into Wednesday morning. This will usher temperatures well below normal into our region.

Low temperatures Monday, Tuesday, and Wednesday morning are forecasted to be in the low to mid 20s across most locations, except the upper 20s along the immediate coast, and near freezing at the beaches. Light winds each night could drop wind chills a few degrees further. If temperatures/wind chills drop to 20 degrees or colder, Cold Weather Advisories would be needed. The most likely locations of this occurring are across our interior GA counties Monday and Tuesday mornings.

.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...

16/18z TAF Discussion: KCHS/KJZI/KSAV: VFR through 17/18z.

Extended Aviation Outlook: A period of flight restrictions in showers is likely Sunday morning at all three terminals.

.MARINE...

There are no concerns tonight into Saturday, but winds are forecast to increase Sunday as a cold front pushes offshore and low pressure develops off the Southeast U.S./Mid-Atlantic coast. Winds may reach Small Craft Advisory thresholds Sunday morning with the onset of cold air advection and linger into Sunday night. Small Craft Advisories are possible, especially over the Georgia offshore waters where the probabilities for wind gusts 25 kt or higher are the greatest.

The periphery of High pressure will be across the coastal waters Monday, with the High moving over the Southeast U.S. Tuesday night. Winds and seas are expected to remain below Small Craft Advisory criteria during this time period.

.CHS WATCHES/WARNINGS/ADVISORIES...

GA...None. MORNING... SC...None. MARINE...None.

ST/