172
FXUS62 KCAE 202013
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
313 PM EST MON JAN 20 2025
SYNOPSIS
WELL BELOW NORMAL TEMPERATURES ARE EXPECTED THROUGH THE WEEK AS
AN ANOMALOUSLY DEEP TROUGH AND SURFACE HIGH PUSHES AN ARCTIC
AIR MASS INTO THE CENTRAL AND EASTERN US. A CHANCE OF SNOW REMAINS
IN THE SOUTHEASTERN MIDLANDS ON TUESDAY NIGHT INTO WEDNESDAY
MORNING. COLD WEATHER IS EXPECTED TO CONTINUE THROUGH FRIDAY, WITH
ONE OR MORE COLD WEATHER ADVISORIES POSSIBLE. TEMPERATURES ARE
FORECAST TO BEGIN WARMING TO NEAR NORMAL AGAIN OVER THE WEEKEND.
NEAR TERM /UNTIL 6 AM TUESDAY MORNING/
KEY MESSAGE(S):
- THE COLDEST AIRMASS SO FAR THIS SEASON IS SETTLING OVER THE AREA
- A COLD WEATHER ADVISORY IS IN EFFECT TONIGHT WITH WIND CHILL
VALUES OF 10 TO 15 DEGREES OVERNIGHT INTO TUESDAY MORNING.
THE PATTERN IS DOMINATED BY AN ELONGATED TROUGH EXTENDING FROM THE
GREAT LAKES REGION INTO THE DESERT SOUTHWEST. POTENT ARCTIC HIGH
PRESSURE CONTINUES TO DIVE SOUTH THROUGH THE ROCKIES INTO THE
PLAINS, AND STARTING TO EXTEND TOWARD THE EAST COAST. SKI ES HAVE
BEEN CLEAR TODAY WITH THIS PATTERN IN PLACE, AND COLD ADVECTION HAS
LIMITED OUR WARMING QUITE A BIT. TEMPERATURES THIS AFTERNOON ARE IN
THE UPPER 30S TO ABOUT 40 IN MOST SPOTS, WITH DEWPOINTS QUITE DRY IN
THE MID TEENS.
TEMPERATURES SHOULD DROP QUICKLY THIS EVENING AS THE HIGH CONTINUES
TO BUILD EAST AND THE UPPER TROUGH ALSO TRANSLATES TOWARD THE EAST
COAST. DEWPOINTS WILL FALL INTO THE SINGLE DIGITS WITH CLEAR SKIES
TO BEGIN THE NIGHT, THOUGH SOME HIGH LEVEL CLOUDS ARE LIKELY TO
START STREAMING ACROSS THE AREA TOWARD DAYBREAK. STILL, LOWS SHOULD
FALL INTO THE UPPER TEENS TO LOW 20S, AND SOME LINGERING NORTHEAST
WINDS SHOULD GENERATE REAL-FEEL TEMPERATURES IN THE LOW TO MID TEENS
AND PERHAPS SOME SINGLE DIGITS ALONG THE SC/NC BORDER. THEREFORE, A
COLD WEATHER ADVISORY WILL BE IN EFFECT TONIGHT FOR ALL OF THE SC
MIDLANDS AND CSRA.
SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY/
KEY MESSAGE(S):
- VERY COLD TEMPERATURES CONTINUE THROUGH THE SHORT TERM.
- WINTER STORM REMAINS ON TRACK TO AFFECT THE REGION TUESDAY LATE
AFTERNOON/EVENING.
- WINTER WEATHER ADVISORY ISSUED FOR THE EASTERN MIDLANDS.
DID I MENTION FORECASTING WINTER WEATHER IS SO MUCH FUN?!?!?!?!
ANYWAY, ONE THING WE REMAIN HIGHLY CONFIDENT ABOUT IS THE COLD AIR
FOR TUESDAY INTO WEDNESDAY AS ARCTIC AIR CONTINUES TO FILTER IN FROM
THE NORTHWEST. AFTERNOON HIGHS ARE EXPECTED TO BE AROUND 20 DEGREES
BELOW NORMAL FOR BOTH DAYS. WEDNESDAY'S HIGHS WILL BE PARTIALLY
DEPENDENT ON ANY SNOW COVER FROM THE EXPECTED WINTER SYSTEM.
OVERNIGHT TEMPS ARE EXPECTED TO DROP INTO THE UPPER TEENS TO LOWER
20S, BUT WINDS ARE EXPECTED TO STAY ELEVATED CAUSING WIND CHILLS IN
THE LOWER TEENS OR SINGLE DIGITS AT TIMES. DUE TO THE COLD TEMPS
DURING THE DAY AND FRIGID TEMPS OVERNIGHT, WE HAVE EXTENDED THE
COLD WEATHER ADVISORY UNTIL 10 AM ON WEDNESDAY.
NOW, FOR THE "FUN" PART. ALMOST ALL OF THE 12Z GUIDANCE HAS SHIFTED
THE UPCOMING STORM TRACK BACK TO THE NORTH AND WEST A BIT AS WELL,
WHICH HAS LED TO AN UPTICK IN SNOW AMOUNTS FOR THE FORECAST AREA.
ANOTHER TREND SOME GUIDANCE HAS BEEN SHOWING IS POSSIBLY AN EARLIER
ONSET OF THE SNOWFALL FOR THE FORECAST AREA, WHICH SEEMS REASONABLE
GIVEN MODELS DON'T TYPICALLY HANDLE INITIAL WARM AIR ADVECTION
PRECIPITATION WELL WITH THESE SYSTEMS. THE MOST LIKELY ONSET TIME
REMAINS IN THE 3-8 PM TIME PERIOD, HOWEVER. IT STILL LOOKS LIKE A
QUICK MOVING SYSTEM, HOWEVER, AND IS LIKELY OUT OF THE AREA BEFORE
DAWN. A LIMITING FACTOR CONTINUES TO BE SOME DRY AIR IN THE LOWER
LEVELS, WHICH COULD LIMIT SNOW TOTALS. A CHANGE WITH THE LATEST
HIRES GUIDANCE IS THAT THE LOWER LEVELS DO MOISTEN UP FOR AREAS
SOUTH OF THE I-20 CORRIDOR, SO CONFIDENCE HAS INCREASED FOR
ACCUMULATING SNOW FOR THOSE AREAS. CONFIDENCE IS HIGHEST FOR AROUND
AN INCH OF SNOW IN THE EASTERN MIDLANDS, SO WE'VE ISSUED A WINTER
WEATHER ADVISORY FOR THOSE AREAS. STILL EXPECTING A SHARP GRADIENT
BETWEEN ACCUMULATING SNOW AND NO SNOW, BUT UNCERTAINTY REMAINS IN
EXACTLY WHERE THAT GRADIENT WILL WIND UP. WE'LL CONTINUE TO MONITOR
MODEL TRENDS TO DETERMINE ADDITIONAL CHANGES TO FORECAST AMOUNTS AND
IF AN EXPANSION OF THE WINTER WEATHER ADVISORY WILL BE NEEDED. AS
WE'VE BEEN MENTIONED, THE LINGERING COLD AIR WILL LIKELY CAUSE ANY
SNOW ON THE GROUND TO STICK AROUND A LITTLE LONGER THAN TYPICAL FOR
THE AREA.
LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/
KEY MESSAGE(S):
- INCREASING CLOUDS WEDNESDAY NIGHT MAY LIMIT COOLING AND THE NEED
FOR ANOTHER COLD WEATHER ADVISORY.
- TEMPERATURES GRADUALLY WARM THROUGH THE EXTENDED.
WEDNESDAY NIGHT: CLOUDS INCREASE WEDNESDAY NIGHT AS A WEAK AREA OF
LOW PRESSURE DEVELOPS OFF THE COAST. THE 12Z CANADIAN CONTINUES ITS
TREND OF PRODUCING FREEZING RAIN ACROSS THE COASTAL PLAIN, BUT NO
LONGER HAS ICE ACCUMULATIONS IN OUR CWA. THIS, COMBINED WITH THE VERY
DRY AIR MASS IN PLACE AND THAT FACT THAT THE DETERMINISTIC GFS AND
EURO DO NOT SHOW ANY PRECIPITATION DURING THIS TIME PERIOD, LED ME
TO REMOVE ANY PRECIPITATION CHANCES FROM THE FORECAST. SHOULD ANY
PRECIPITATION FALL DURING THE PERIOD, IT SHOULD BE GENERALLY LIGHT
AND FOCUSED ALONG AND EAST OF I-95. THE OTHER QUESTION FOR WEDNESDAY
NIGHT IS WHETHER THESE CLOUDS WILL LIMIT COOLING ENOUGH THAT A COLD
WEATHER ADVISORY WILL NOT BE NEEDED. THE CURRENT FORECAST CALLS FOR
MINIMUM TEMPERATURES IN THE MID TO UPPER TEENS SO IT WILL BE ANOTHER
COLD NIGHT REGARDLESS OF WHETHER CRITERIA IS MET.
THURSDAY SHOULD ONCE AGAIN FEATURE WELL BELOW NORMAL TEMPERATURES,
ESPECIALLY IF THERE ARE CLOUDS IN PLACE, BUT FORECAST HIGHS ARE
ABOUT 5 DEGREES WARMER THAN TUESDAY AND WEDNESDAY. THIS WILL KICK
OFF A GRADUAL WARMING TREND THROUGH THE EXTENDED, WITH VALUES
RETURNING TO NEAR NORMAL VALUES BY SUNDAY. ANY ADDITIONAL
PRECIPITATION CHANCES SHOULD HOLD OFF UNTIL NEAR THE END OF THE
CURRENT PERIOD, LATE SUNDAY NIGHT INTO MONDAY.
AVIATION /20Z MONDAY THROUGH SATURDAY/
HIGH CONFIDENCE IN VFR CONDITIONS THROUGH THE FORECAST PERIOD.
HIGH PRESSURE WILL KEEP SKIES CLEAR TODAY WITH A DRY AIRMASS IN
PLACE. MID AND HIGH LEVEL CLOUDS WILL BEGIN TO INCREASE LATE TONIGHT
AS SOUTH TO SOUTH-WESTERLY FLOW ALOFT INCREASES AHEAD OF AN
AMPLIFIED UPPER TROUGH. NORTHWEST WINDS 5 TO 10 KNOTS SHIFTING TO
LIGHT NORTHEAST TONIGHT WITH THE SURFACE RIDGE SETTING UP TO THE
NORTH OF THE AREA. NORTHEAST WINDS THEN CONTINUE INTO TUESDAY AS
CLOUD COVER INCREASES AND CLOUD BASES DROP. FOR THIS TAF PERIOD,
EXPECT VFR CONDITIONS TO PERSIST.
EXTENDED AVIATION OUTLOOK
RESTRICTIONS POSSIBLE LATE TUESDAY
INTO TUESDAY NIGHT AS MOISTURE INCREASES AND LOW PRESSURE MOVES
NEAR THE COAST WITH SOME POSSIBLE WINTRY PRECIPITATION TUESDAY
NIGHT INTO WEDNESDAY MORNING.
CAE WATCHES/WARNINGS/ADVISORIES
SC...COLD WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 10 AM EST
WEDNESDAY FOR SCZ016-018-020>022-025>031-035-037-038-041-
115-116-135>137.
WINTER WEATHER ADVISORY FROM 5 PM TUESDAY TO 9 AM EST
WEDNESDAY FOR SCZ035-038-041-136-137.
GA...COLD WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 10 AM EST
WEDNESDAY FOR GAZ040-063>065-077.
WINTER WEATHER ADVISORY FROM 5 PM TUESDAY TO 9 AM EST
WEDNESDAY FOR GAZ077.
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