600
FXUS62 KCAE 182055
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
355 PM EST SAT JAN 18 2025
SYNOPSIS
AFTER A QUIET PERIOD THIS AFTERNOON, ANOTHER ROUND OF SHOWERS IS
EXPECTED TO MOVE THROUGH THE AREA TONIGHT AS A COMPLEX LOW PRESSURE
SYSTEM MOVES INTO THE EASTERN U.S. A STRONG COLD FRONT WILL MOVE
THROUGH THE AREA BY MIDDAY SUNDAY WITH STRONG GUSTY WINDS IN ITS
WAKE THROUGH THE AFTERNOON. BEHIND THE FRONT, VERY COLD AIR WILL
BEGIN TO SPREAD ACROSS THE REGION. WELL BELOW NORMAL TEMPERATURES
ARE EXPECTED NEXT WEEK AS AN ANOMALOUSLY DEEP TROUGH AND SURFACE
HIGH PUSHES AN ARCTIC AIR MASS INTO THE CENTRAL AND EASTERN US. ON
TUESDAY, A COASTAL LOW WILL LIKELY INCREASE PRECIPITATION CHANCES
WITH WINTRY POTENTIAL INCREASING, BUT SOME UNCERTAINTY REMAINS.
NEAR TERM /UNTIL 6 AM SUNDAY MORNING/
KEY MESSAGE(S):
- CLOUDS MOVE BACK IN THIS EVENING AS ANOTHER ROUND OF RAIN IS
EXPECTED TONIGHT.
A FEW GLIMPSES OF SUN ACROSS THE FORECAST AREA THIS AFTERNOON WILL
BE REPLACED BY INCREASING CLOUDS AS A SHORTWAVE TROUGH PUSHES
THROUGH THE AREA. A LULL IN THE RAIN IS EXPECTED THROUGH THIS
EVENING, BUT DURING THIS TIME VERY LOW CLOUDS ARE LIKELY TO
REDEVELOP. SOME WEAK WARM ADVECTION HAS PUSHED TEMPERATURES INTO THE
50S TO NEAR 60 WITH THE BREAKS IN THE CLOUDS, ALONG WITH DEWPOINTS
INTO THE UPPER 40S TO AROUND 50.
ANOTHER SHORTWAVE WILL MOVE THROUGH THE AREA TONIGHT, WITH A SURFACE
LOW DEVELOPING NEAR THE FORECAST AREA. PWATS ARE FORECAST TO RAPIDLY
INCREASE TO AROUND 1.0" AS THIS OCCURS AND WIDESPREAD SHOWERS ARE
LIKELY TO DEVELOP AGAIN THIS EVENING. ACCUMULATIONS SHOULD REMAIN
UNDER AN INCH FOR MOST PLACES BY THE TIME ALL IS SAID AND DONE.
CLOUD COVER AND PRECIP ALONG WITH SOME INCREASING BOUNDARY LAYER
WINDS TOWARD DAYBREAK WILL KEEP LOWS MILD, ONLY FALLING INTO THE
UPPER 40S TONIGHT.
SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/
KEY MESSAGE(S):
- A STRONG COLD FRONT PUSHES THROUGH SUNDAY WITH A VERY COLD AIRMASS
SETTLING OVER THE AREA BY MONDAY.
- BREEZY CONDITIONS ALONG THE FRONT HAVE PROMPTED THE ISSUANCE OF A
LAKE WIND ADVISORY FOR SUNDAY AFTERNOON.
- A COLD WEATHER ADVISORY MAY BE NEEDED MONDAY NIGHT AS TEMPERATURES
DROP INTO THE 20S AND WIND CHILLS FALL INTO THE TEENS.
SUNDAY AND SUNDAY NIGHT...THE HIGHLY AMPLIFIED UPPER TROUGH FROM THE
UPPER MIDWEST SOUTH THROUGH THE MISSISSIPPI VALLEY WILL BE BE
LIFTING INTO THE MID ATLANTIC REGION ON SUNDAY. DEVELOPING LOW
PRESSURE IS PROGGED TO TRACK ACROSS THE AREA, AND A SHARP COLD FRONT
WILL SWEEP ACROSS THE STATE DURING THE DAY. ANY LINGERING SHOWERS
FROM THE OVERNIGHT SYSTEM WILL END BY MIDDAY, AND WINDS WILL
INCREASE WITH A TIGHT SURFACE PRESSURE GRADIENT. THERE ARE 80%+ LREF
HREF PROBABILITIES OF WIND GUSTS OF 30+MPH, AND A LAKE WIND ADVISORY
HAS BEEN HOISTED FOR TOMORROW. STRONG COLD ADVECTION WILL DEVELOP IN
THE AFTERNOON WITH STRONG MIXING, BUT NOT BEFORE HIGH TEMPERATURES
PEAK AROUND 60 DEGREES. THIS WILL BE SHORT LIVED WITH TEMPERATURES
RAPIDLY DECREASING THROUGH THE AFTERNOON INTO THE EVENING AS THE
BOUNDARY LAYER RAPIDLY DRIES OUT. THE ARCTIC AIRMASS MOVING INTO THE
REGION WILL ENSURE TEMPERATURES FALLING INTO THE 20S OVERNIGHT, WITH
SOME WIND CHILL VALUES IN THE UPPER TEENS. A COLD WEATHER ADVISORY
WAS CONSIDERED, BUT AT THIS POINT IT LOOKS A BIT BORDERLINE
ESPECIALLY CONSIDERING THE COLD TO COME IN THE NEXT FEW DAYS.
MONDAY AND MONDAY NIGHT...THE ARCTIC AIR MASS (1040 MB HIGH PRESSURE
SITUATED TO THE NORTH) WILL BE SETTLING IN WITH DEWPOINTS IN THE
SINGLE DIGITS AND TEENS. THIS WILL BE THE LAST MOSTLY CLEAR DAY FOR
MUCH OF THE WEEK, AND DESPITE THE SUNSHINE TEMPERATURES WILL
STRUGGLE AND LIKELY ONLY MAKE IT TO THE UPPER 30S NORTH TO LOW 40S
SOUTH AS COLD AIR ADVECTION CONTINUES. MONDAY NIGHT LOWS FALL
TO THE UPPER TEENS AND LOW 20S, WITH WIND CHILL VALUES IN THE
LOW TO MID TEENS WHICH MAY PROMPT THE ISSUANCE OF A COLD WEATHER
ADVISORY ON SUBSEQUENT SHIFTS. PREPARATIONS SHOULD BE MADE NOW
FOR SEVERAL DAYS OF VERY COLD TEMPERATURES.
LONG TERM /TUESDAY THROUGH SATURDAY/
KEY MESSAGE(S):
- MULTIPLE IMPACTFUL HAZARDS EXPECTED.
1) HIGH CONFIDENCE IN THE COLDEST AIR OF THE YEAR TUES.-THURS.
2) CONFIDENCE CONTINUES TO INCREASE FOR IMPACTFUL WINTER WEATHER
WEATHER TUES. INTO WED.
1) HIGH CONFIDENCE IN COLDEST AIR OF THE YEAR TUES.-THURS.
ARCTIC HIGH PRESSURE IS FORECAST TO BE OVER THE MID-ATLANTIC REGION
TO BEGIN THE LONG TERM PERIOD, WHICH WILL LIKELY ALLOW FOR THE
COLDEST AIR OF THE SEASON TO CONTINUE SETTLING INTO THE REGION.
EXPECT THIS COLD TO REMAIN IN THE AREA INTO THURSDAY. ALL SIGNS
CONTINUE TO SHOW THAT A COLD WEATHER ADVISORY WILL NEED TO BE IN
PLACE FOR THE MID WEEK TIME PERIOD. THE COLD AIR LOOKS TO BE
REINFORCED BY A PASSING COASTAL LOW (MORE ON THAT IN NEXT PARAGRAPH),
RESULTING IN HIGH CONFIDENCE THAT THE COLDEST AIR STICKS AROUND INTO
THURSDAY. TEMPERATURES TUESDAY THROUGH THURSDAY AFTERNOON MIGHT
STRUGGLE TO GET OUT OF THE 30S, AND THERE IS MODERATE CONFIDENCE
(~50%) THAT MANY AREAS WON'T TOP THE FREEZING MARK ON WEDNESDAY.
WITH SUCH A COLD STRETCH EXPECTED, TAKE THE NECESSARY MEASURES TO
STAY WARM, PREVENT WATER PIPES FROM BURSTING, AND LIMIT TIME
OUTDOORS.
2) CONFIDENCE CONTINUES TO INCREASE FOR IMPACTFUL WINTER WEATHER
WEATHER TUES. INTO WED.
CONFIDENCE OF INGREDIENTS BEING IN PLACE FOR AN IMPACTFUL WINTER
WEATHER SYSTEM CONTINUE TO INCREASE AS MODELS ARE NOW COMING INTO
BETTER AGREEMENT WITH A COASTAL LOW FORECAST TO MOVE ALONG THE
SOUTHEAST COAST. THE AFOREMENTIONED COLD AIR IS VERY LIKELY TO BE IN
PLACE ON TUESDAY. A DEVELOPING LOW IN THE GULF OF MEXICO IS FORECAST
TO MOVE EASTWARD ACROSS FLORIDA, THEN ALONG THE SOUTHEAST COAST.
LATEST 12Z GUIDANCE CONTINUES TO SHOW WINTER PRECIPITATION, LIKELY
SNOW, LOOKS PROBABLE FOR OUR FORECAST AREA TUESDAY AFTERNOON INTO
THE OVERNIGHT HOURS. HOWEVER, THERE IS SOME DISAGREEMENT IN THE
AMOUNT. FOR EXAMPLE, THE EURO ENSEMBLE IS SHOWING 80-90% CHANCE OF
AT LEAST AN INCH OF SNOW FOR AREAS SOUTH AND EAST OF THE I-20
CORRIDOR, WHILE THE GEFS ENSEMBLE IS ONLY SHOWING A 20-30% CHANCE IN
THE SAME AREAS. THE NBM AND LREF ENSEMBLES ARE INDICATING ABOUT A
50% CHANCE OF AT LEAST AN INCH, WHICH SEEMS REASONABLE TO ME
GIVEN THE FORECAST SET UP. WITH THE ARCTIC HIGH REMAINING NEAR
THE AREA, SOME REALLY DRY AIR IS LIKELY TO BE IN PLACE, WHICH
WILL NEED TO BE OVERCOME FOR SNOW AMOUNTS OVER AN INCH. BECAUSE
OF THIS DRY AIR, THERE IS LIKELY GOING TO BE A SHARP CUTOFF
BETWEEN SNOW ACCUMULATION AND LITTLE TO NO ACCUMULATION. ANOTHER
FACTOR THAT LOOKS TO LIMIT ACCUMULATION IS THE SPEED THAT THE
SYSTEM IS FORECAST TO MOVE THROUGH. AS OF NOW, IT'S LOOKING LIKE
A TUESDAY AFTERNOON INTO TUESDAY NIGHT SYSTEM AND BE OUT OF THE
AREA BY WEDNESDAY MORNING. DESPITE A QUICK MOVING SYSTEM, A
POINT THAT ALSO NEEDS MENTIONING IS THAT WITH THE COLD AIR IN
PLACE INTO THURSDAY, ANY SNOW THAT IS ABLE TO FALL/ACCUMULATE IS
LIKELY TO HANG AROUND FOR A COUPLE OF DAYS. SO BE PREPARED TO
DEAL WITH TRAVEL IMPACTS BEYOND THE TYPICAL SNOWFALL IN THIS
AREA.
AVIATION /21Z SATURDAY THROUGH THURSDAY/
WIDESPREAD RESTRICTIONS EXPECTED FOR MUCH OF THE PERIOD.
THE FIRST ROUND OF RAIN IS EXITING TO THE EAST OF THE AREA AND
SHOULD KEEP THE TAF SITES CLEAR FOR MUCH OF THE AFTERNOON.
RESTRICTIONS MAY EASE FOR A FEW HOURS AS A RESULT, BUT GUIDANCE
REMAINS IN GOOD AGREEMENT THAT DETERIORATING CONDITIONS WILL RETURN
THIS EVENING THROUGH TONIGHT. SCATTERED TO NUMEROUS SHOWERS ARE
EXPECTED TO RETURN TO THE AREA FROM SOUTHWEST TO NORTHEAST AFTER
19/00Z, WITH BOTH CIGS AND VSBYS DROPPING AS MOISTURE INCREASES
PARTICULARLY IN THE LOWER LEVELS. -SHRA THEN EXPECTED TO CONTINUE
THROUGH DAYBREAK SUNDAY, AND PERHAPS FOR A FEW HOURS MORE, BEFORE
CLEARING OUT TO THE EAST. HAVE CONTINUED CIG RESTRICTIONS UNTIL THE
END OF THE VALID TAF PERIOD, BUT THEY MAY START TO EAST AN HOUR OR
TWO PRIOR.
WINDS WILL GENERALLY BE LIGHT AND VARIABLE OR SLY TODAY, GENERALLY
LESS THAN 12 KTS. WE SHOULD SEE A PERIOD OF LIGHT AND VARIABLE WINDS
AROUND 19/00Z, THEN A BIT OF STRENGTHENING FROM THE S/SW AFTER
19/06Z AS A SURFACE LOW TRACKS ACROSS THE AREA. SPEEDS INCREASE
SUNDAY MORNING AFTER SUNRISE TO 10-15 KTS AND CONTINUE VEERING W AND
EVENTUALLY NW BY SUNDAY AFTERNOON, BECOMING QUITE BREEZY WITH GUSTS
OF 25-30 KTS.
EXTENDED AVIATION OUTLOOK
EXPECTING CEILING RESTRICTIONS TO
CONTINUE INTO SUNDAY MORNING. COLD FRONT IS FORECAST TO PASS
THROUGH THE AREA BY SUNDAY AFTERNOON, WHICH SHOULD IMPROVE
CONDITIONS. GUSTY WINDS ARE EXPECTED WITH THIS COLD FRONT. NO
RESTRICTIONS ARE EXPECTED MONDAY, BUT COULD RETURN ON TUESDAY WITH
THE NEXT WEATHER SYSTEM.
CAE WATCHES/WARNINGS/ADVISORIES
SC...LAKE WIND ADVISORY FROM 10 AM TO 11 PM EST SUNDAY FOR SCZ016-
018-020>022-025>031-035-037-038-041-115-116-135>137.
GA...LAKE WIND ADVISORY FROM 10 AM TO 11 PM EST SUNDAY FOR GAZ040-
063>065-077.
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