006
FXUS62 KCAE 180118
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
818 PM EST SAT JAN 17 2026
WHAT HAS CHANGED
WINTER WEATHER ADVISORY ISSUED FOR BURKE, COLUMBIA, LINCOLN,
MCDUFFIE, AND RICHMOND COUNTIES FROM 4 AM TO 3 PM EST SUNDAY.
KEY MESSAGES
- 1) SNOW MAY CAUSE HAZARDOUS TRAVEL IN THE CSRA SUNDAY MORNING.
- 2) AN ARCTIC AIR MASS ARRIVES EARLY NEXT WEEK.
DISCUSSION
KEY MESSAGE 1: SNOW MAY CAUSE HAZARDOUS TRAVEL IN THE CSRA
SUNDAY MORNING.
EVENING UPDATE:
MODELS HAVE CONTINUED TO SHOW A SHARPER, MORE NEUTRAL OR
NEGATIVELY TILTED UPPER LEVEL TROUGH COMPARED TO RUNS FROM
PREVIOUS DAYS. ULTIMATELY THIS HAS LED TO STRONGER SYNOPTIC
SUPPORT FOR PRECIPITATION WITH MOISTURE FURTHER WEST AND
LINGERING OVER THE REGION FOR LONGER THROUGH THE DAY.
WIDESPREAD RAIN IS EXPECTED TO MOVE INTO THE AREA EARLY SUNDAY
MORNING. WITH TEMPERATURES MAINLY IN THE LOW OR MID 40S THROUGH
THE OVERNIGHT PERIOD, IT WOULD BE UNLIKELY TO SEE ANYTHING BUT
RAIN PRIOR 6AM. IT WON'T BE UNTIL LATER IN THE MORNING WHEN WE
SEE COLD AIR RUSH IN FROM THE WEST THAT THERE IS SOME POTENTIAL
FOR A RAIN-SNOW MIX TO DEVELOP INTO MID-DAY. IT'S WORTH NOTING
THAT THIS SETUP WHERE COLD AIR COMES IN LATE IN THE EVENT DOES
NOT NORMALLY LEAD TO SIGNIFICANT SNOWFALL ACCUMULATIONS FOR OUR
REGION.
THE MAIN CONCERN IS IF A HEAVIER BAND OF PRECIP SETS UP SUNDAY
MORNING. WITH GREATER DYNAMICS IN RECENT MODEL RUNS WE ARE MORE
CONFIDENT THAT THERE WILL BE A HEAVIER BAND THAT DEVELOPS. THIS
COULD COOL THE LOW LEVELS DYNAMICALLY AND ALLOW SNOW TO REACH
THE GROUND DESPITE ABOVE FREEZING SURFACE TEMPERATURES. MODERATE
SNOWFALL RATES WOULD CAUSE IMPACTS TO TRAVEL FOR OUR REGION
EVEN SHORT LIVED OR IF IT DID NOT AMOUNT IN SIGNIFICANT
ACCUMULATIONS. ALTHOUGH IT'S NOT POSSIBLE TO PIN DOWN EXACTLY
WHERE THIS BAND WILL SET UP TOMORROW, OUR CONFIDENCE IS HIGHEST
IN EASTERN GA. THEREFORE A WINTER WEATHER ADVISORY HAS BEEN
ISSUED FOR THE GA COUNTIES IN THE CSRA FOR SUNDAY MORNING INTO
MID-DAY.
PREVIOUS DISCUSSION:
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: AN ARCTIC AIR MASS ARRIVES EARLY NEXT WEEK.
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 /00Z SUNDAY THROUGH THURSDAY/
CONDITIONS DETERIORATE AT THE TERMINALS TONIGHT....
SATELLITE IMAGERY THIS EVENING SHOWS CLEAR SKIES AT OGB WITH
SCATTERED CLOUDS AT THE OTHER TERMINALS. THICKER CLOUDS SHOULD MOVE
INTO AGS/DNL SHORTLY FOLLOWED BY CAE/CUB/OGB. NO SIGNIFICANT
ADJUSTMENTS TO THE PREVIOUS FORECAST WERE MADE WITH THIS UPDATE.
RAIN CHANCES INCREASE THIS EVENING WITH RAIN LIKELY TONIGHT AND INTO
SUNDAY MORNING. CEILINGS SHOULD CONTINUE TO FALL AS THE NIGHT GOES
ON, WITH MVFR TO IFR CLOUD DECKS DEVELOPING PRIOR TO DAYBREAK
SUNDAY. UNCERTAINTY REMAINS REGARDING THE POTENTIAL CHANGEOVER TO A
RAIN/SNOW MIX NEAR THE END OF THE EVENT, BUT MAINTAINED THE MIX AT
AGS/DNL WITH THIS UPDATE. WOULD NOT BE SURPRISED IF AT LEAST SOME
MIXING OCCURS DURING THE LATE MORNING AND EARLY AFTERNOON HOURS OF
SUNDAY AT THE OTHER TERMINALS, BUT SNOW RELATED IMPACTS ARE MOST
LIKELY TO OCCUR ALONG AND SOUTH OF THE SAVANNAH RIVER. CONDITIONS
SHOULD IMPROVE QUICKLY LATE IN THE DAY, TOWARDS THE END OF THE
CURRENT TAF PERIOD.
EXTENDED AVIATION OUTLOOK...VFR EXPECTED BEGINNING SUNDAY
EVENING AND LASTING THROUGH AT LEAST MID WEEK.
CAE WATCHES/WARNINGS/ADVISORIES
SC...NONE.
GA...WINTER WEATHER ADVISORY FROM 4 AM TO 3 PM EST SUNDAY FOR
GAZ040-063>065-077.
DISCUSSION...CJR
AVIATION...SAL
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