654
FXUS62 KCAE 171812
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
112 PM EST SAT JAN 17 2026
WHAT HAS CHANGED
THE NEWEST ROUND OF GUIDANCE CONTINUES TO SUGGEST THE POTENTIAL
FOR A SNOW BAND OVER PARTS OF THE AREA SUNDAY MORNING,
POTENTIALLY CONTINUING INTO THE EARLY AFTERNOON. CONFIDENCE IN
WINTER WEATHER ADVISORY ACCUMULATIONS REMAIN TOO LOW FOR
ISSUANCE AT THIS TIME, BUT THIS WILL NEED TO BE MONITORED THE
REMAINDER TODAY.
KEY MESSAGES
1) A RAIN/SNOW MIX IS EXPECTED TO START SUNDAY MORNING, POSSIBLY
WITH A BAND OF ENHANCED RATES. SIGNIFICANT ACCUMULATION
PROBABILITIES REMAIN LOWER, BUT THERE HAS BEEN A UPTICK IS
POSSIBLE AMOUNTS TOWARD THE CSRA. PATCHY BLACK ICE IS STILL
POSSIBLE EARLY MONDAY MORNING.
2) ARCTIC AIR MASS MOVES INTO THE SOUTHEAST EARLY NEXT WEEK WITH
TEMPERATURES WELL BELOW NORMAL THROUGH WEDNESDAY.
DISCUSSION
KEY MESSAGE 1: A RAIN/SNOW MIX IS EXPECTED TO START SUNDAY
MORNING, POSSIBLY WITH A BAND OF ENHANCED RATES. SIGNIFICANT
ACCUMULATION PROBABILITIES REMAIN LOWER, BUT THERE HAS BEEN A
UPTICK IS POSSIBLE AMOUNTS TOWARD THE CSRA. PATCHY BLACK ICE IS
STILL POSSIBLE EARLY MONDAY MORNING.
WITH THE NEXT ROUND OF GUIDANCE IN, THERE HAS NOT BEEN A
SIGNIFICANT CHANGE FROM A SYNOPTIC STANDPOINT. THE MAIN
NOTICEABLE CHANGE AT THIS SCALE IS THERE IS BETTER CONSENSUS ON
THE SHARP SHORTWAVE TROUGH BECOMING A BIT MORE NEGATIVELY TILTED
AS IT NEARS THE AREA WITH CYCLOGENESIS ENSUING ALONG THE COAST.
THIS HAS AMPED UP THE OVERALL DYNAMIC PROFILE A BIT MORE THAT
IN TURN COULD ALTER THE RATHER MARGINAL THERMODYNAMICS. FIRST,
RAIN IS EXPECTED TO BEGIN OVERSPREADING THE REGION TONIGHT AS
WARM ADVECTION PUSHES IN AND GREATER UPPER SUPPORT NEARS BUT A
RAIN/SNOW MIX IS EXPECTED TO BEGIN FORMING TOWARD EARLY SUNDAY
MORNING IN PARTS OF GA, SPREADING EASTWARD.
NOW FOR THE COMPLICATED PART. WITH THIS SLIGHTLY MORE AMPLIFIED
SHORTWAVE, RECENT 12Z GUIDANCE (MAINLY NAM AND GFS) HAS SHOWN
SOUNDING PROFILES THAT DYNAMICALLY COOL A COUPLE DEGREES MORE
THAN PREVIOUS RUNS AS A SMALL POCKET OF WARMER AIR AT 850MB GETS
LIFTED. SURFACE TEMPERATURES AND SURFACE WET-BULB TEMPERATURES
ARE STILL RATHER MARGINAL IN 12Z RUNS, BUT RATHER THAN OVER 2000
FT OF A TRANSITION ZONE FROM THE BELOW FREEZING LAYER ALOFT TO
THE ABOVE FREEZING LAYER NEAR THE SURFACE, NEW RUNS HAVE THIS
DEPTH CLOSER TO 700-1100FT. HIGH-RES GUIDANCE AND GLOBAL MODELS
ALSO CONTINUE TO SHOW THE RATHER ROBUST FORCING IN THE SATURATED
DGZ. MODELED CROSS SECTIONS SHOULD SOLID OMEGA VALUES IN THE
DGZ WITH MODERATE FORCING FROM FGEN ALSO PRESENT. THIS IS ALL TO
SAY, THE RECENT 12Z GUIDANCE INDICATES ENOUGH FORCING TO
PRODUCE A BAND OF MODERATE PRECIP RATES BUT A LARGE DEGREE OF
UNCERTAINTY REMAINS. THE MAIN UNCERTAINTIES ARE IF THE TURNOVER
FROM RAIN TO A RAIN/SNOW MIX WILL OCCUR, WHEN WILL THE TURNOVER
FROM RAIN TO A RAIN/SNOW MIX OCCUR, AND IF THE RAIN/SNOW MIX
OCCURS, WHERE WILL THE BAND OF MODERATE RATES SET UP.
AT THIS TIME, MOST GUIDANCE IS ON BOARD WITH WIDESPREAD
RAINFALL ACROSS THE FA SUNDAY WITH A RAIN/SNOW MIX DEVELOPING TO
OUR WEST AND THEN PUSHING INTO THE FA SUNDAY MORNING AND INTO
THE EARLY AFTERNOON, ESPECIALLY TOWARD THE CSRA AND PARTS OF THE
MIDLANDS WITH DECREASING CONFIDENCE IN SNOW MIXING IN AS YOU
MOVE TOWARD THE NORTHEAST. NEXT THE MOST RECENT RUNS AND EVEN
SOME OF THE ENSEMBLE AND DETERMINISTIC GUIDANCE LAST NIGHT IS
FAVORING THE MODERATE BAND OF PRECIP RATES TO DEVELOP IN PARTS
OF SOUTH CENTRAL GA, POSSIBLY PUSHING INTO THE CSRA AND FAR
SOUTHEASTERN MIDLANDS.
ALL IN ALL, THE CURRENT OUTLOOK HAS SEEN A SLIGHT INCREASE IN
CHANCES FOR ACCUMULATING SNOW IN THE AFOREMENTIONED AREA WITH
PROBABILITIES FOR WINTER WEATHER ADVISORY LEVEL ACCUMULATIONS
CURRENTLY BETWEEN 25-35% IN THE CSRA ESPECIALLY (UP FROM LAST
NIGHTS GUIDANCE). DUE TO THE HIGH DEGREE OF UNCERTAINTY THAT
REMAINS IN WHERE EXACTLY THE MODERATE PRECIP BAND SETS UP AND IF
SNOW RATES IN THIS BAND WOULD BE ENOUGH TO OVERCOME SURFACE
TEMPERATURES ABOVE FREEZING, HAVE DECIDED TO HOLD OFF ON ANY
ISSUANCE OF A WINTER WEATHER ADVISORY RIGHT NOW, BUT THIS WILL
NEED TO BE MONITORED WITH THE NEXT RUN OF GUIDANCE AS REASONABLE
WORSE CASE SCENARIO SNOW AMOUNTS UP TO 0.5-1" COULD BE POSSIBLE
TOWARD THE CSRA AND PARTS OF THE SOUTHERN MIDLANDS IF THE
MODERATE BAND SETS UP HERE. THE NEXT RISK OVERNIGHT AND INTO
MONDAY MORNING WILL BE WET SURFACES THATS DEVELOP PATCHY BLACK
ICE DUE TO TEMPERATURES THAT QUICKLY FALL INTO THE 20S.
KEY MESSAGE 2: BEHIND THE STORM SYSTEM ON SUNDAY ARRIVES A VERY
COLD AIRMASS. THE SYNOPTIC SCALE PATTERN LOOKS PRETTY SIMILAR
TO WHAT IT HAS BEEN FOR A FEW DAYS NOW WITH DEEP TROUGHING
FAVORED OVER THE EASTERN CONUS. GEFS 5 DAY 500 HPA HEIGHT
ANOMALIES CONTINUE TO LOOK BELOW NORMAL, WITH THE CORE OF THE
UPPER LEVEL TROUGH CENTERED NEAR THE GREAT LAKES AND LOWER
HUDSON BAY. ON THE SOUTHERN SIDE OF THIS, STRONG CONVERGENCE
WILL FAVOR PERSISTENT, STRONG SURFACE HIGH PRESSURE ACROSS THE
EASTERN CONUS. THE INITIAL SURGE OF THIS WILL BE FELT ON SUNDAY
NIGHT AND MONDAY AS COLD ADVECTION USHERS IN TEMPS IN THE 20S BY
MONDAY MORNING. WINDS LOOK LIKE THEY'LL OFFSET WHATEVER
RADIATIONAL COOLING WE COULD POTENTIALLY HAVE WHICH SHOULD HELP
KEEP US FROM SEEING COLD WEATHER ADVISORY CRITERIA. THERE WILL
LIKELY BE SOME ISOLATED SPOTS THAT GET NEAR OUR 15F CRITERIA BUT
IT SHOULDN'T BE WIDESPREAD ENOUGH TO JUSTIFY A PRODUCT. TEMPS
WILL REMAIN BELOW NORMAL BOTH MONDAY AND TUESDAY AS THE SURFACE
HIGH APPROACHES FROM THE WEST. BY TUESDAY NIGHT, THE SURFACE
HIGH IS EXPECTED TO PASS JUST TO OUR NORTH WITH IDEAL
RADIATIONAL COOLING CONDITIONS POSSIBLE. THIS SHOULD RESULT IN
THE COOLEST NIGHT OF THE PERIOD, WITH LOWS DIPPING INTO THE
UPPER TEENS AND LOW 20S. BUT IN GENERAL, LOW TEMPS ARE FORECAST
TO BE 10F-15F BELOW NORMAL SUNDAY NIGHT THROUGH TUESDAY NIGHT.
BE SURE TO AVOID FROZEN PIPES BY LETTING FAUCETS DRIP EACH
NIGHT! PRECIPITATION IS NOT EXPECTED GIVEN THE LOW PW AIR IN THE
REGION.
AVIATION /18Z SATURDAY THROUGH THURSDAY/
AN ACTIVE PERIOD IS EXPECTED FOR THE TAFS AS CLOUDS INCREASE THIS
EVENING, FOLLOWED BY RAINFALL DEVELOPING. MVFR AND IFR CIGS ARE
EXPECTED TO DEVELOP SUNDAY MORNING.
CLOUDS THAT DEVELOPED EARLIER THIS MORNING HAVE TENDED TO DISSIPATE
OVER THE LAST FEW HOURS, WITH SUNSHINE PRESENT AT ALL SITES
CURRENTLY. THE INCREASE IN TEMPERATURES ACROSS THE REGION HAVE LED
TO STRONG LOW LEVEL WINDS MIXING DOWN, WITH CONSISTENT GUSTS OF 18-
22 KNOTS NOTED AT THE TAF SITES. CLOUDS ARE FORECAST TO BEGIN
INCREASING THIS AFTERNOON AND EVENING AS LIFT AND MOISTURE INCREASE
AHEAD OF OUR NEXT SYSTEM. THIS IS EXPECTED TO BE FAIRLY QUICK THIS
EVENING AS THE LIFT WILL INCREASE RAPIDLY. AS EARLY AS 03Z-05Z,
SHOWERS ARE EXPECTED TO DEVELOP ACROSS THE CSRA AND NORTHERN
MIDLANDS AS A COLD FRONT SINKS TOWARDS AND THROUGH THE FORECAST
AREA. THIS RAIN WILL QUICKLY BECOME MORE WIDESPREAD AFTER 06Z,
OVERSPREADING ALL OF THE TAF SITES. AS COOLER AIR FILTERS IN BEHIND
THE SURFACE FRONT, LOW CLOUDS ARE FORECAST TO DEVELOP ACROSS THE
AREA THEREAFTER. MVFR AND IFR CIGS ARE LIKELY FROM 08Z-10Z THROUGH
THE END OF THE PERIOD AT ALL SITES AS MODERATE RAIN OVERSPREADS THE
SITES. THE WEATHER THEN GETS QUITE INTERESTING, ESPECIALLY AT THE
AUGUSTA SITES. THERE IS EXPECTED TO BE A PERIOD OF RAIN/SNOW MIX AT
THESE SITES FROM 13Z-18Z AS COOLER AIR FILTERS IN BEHIND THE FRONT.
UNCERTAINTY EXISTS AS TO WHEN RAIN WILL CHANGE OVER TO SNOW AND HOW
MUCH WILL ACTUALLY FALL. HOWEVER, CONFIDENCE IS HIGH ENOUGH IN THE
MIX TO PUT IT IN THE TAFS AT THIS POINT. IT IS UNLIKELY THAT OGB
WILL SEE ANY SNOW, AND THE PROBABILITIES AT CAE/CUB ARE LOW ENOUGH
RIGHT NOW TO PRECLUDE ANY MENTION. BUT WE'LL NEED TO KEEP AN EYE ON
IT TODAY AND TONIGHT. BY THE VERY END OF THIS PERIOD, PRECIP IS
EXPECTED TO SLOWLY PUSH TO THE NORTHEAST, WITH RESTRICTIONS LIKELY
TO END QUICKLY AFTER 18Z ON SUNDAY.
EXTENDED AVIATION OUTLOOK...VFR EXPECTED BEGINNING SUNDAY
AFTERNOON AND LASTING THROUGH AT LEAST MID WEEK.
CAE WATCHES/WARNINGS/ADVISORIES
SC...NONE.
GA...NONE.
DISCUSSION...17/82
AVIATION...82
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page