457
FXUS62 KCAE 210202
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
902 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):
- A COLD WEATHER ADVISORY IS IN EFFECT TONIGHT WITH WIND CHILL
VALUES OF 10 TO 15 DEGREES OVERNIGHT INTO TUESDAY MORNING.
A 500 MB TROUGH AT THE NAEFS CLIMATOLOGICAL MINIMUM IS DIGGING
INTO THE CENTRAL US. AT THE SURFACE, AN ARCTIC AIR MASS WILL
PUSH INTO THE SOUTHEAST WITH COLD ADVECTION DRIVING TEMPERATURES
DOWN INTO THE UPPER TEENS TO LOW 20S TONIGHT. AS A SURFACE
BOUNDARY BACKDOORS INTO THE FORECAST AREA FROM THE NORTH TONIGHT
THE PRESSURE GRADIENT WILL INCREASE KEEPING WINDS UP THROUGH
THE MORNING. THE NE WINDS MAY ALLOW FOR WIND CHILL VALUES
BETWEEN 10 TO 15 DEGREES. THEREFORE, A COLD WEATHER ADVISORY IS
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 /00Z TUESDAY THROUGH SATURDAY/
HIGH CONFIDENCE IN VFR CONDITIONS THROUGH THE FORECAST PERIOD
ALTHOUGH LOWERING CIGS EXPECTED THROUGH THE DAY TUESDAY.
COLD AND DRY HIGH PRESSURE CONTINUES TO BUILD INTO THE REGION
FROM A STRONG HIGH PRESSURE SYSTEM CENTERED OVER THE CENTRAL
PLAINS. SATELLITE IMAGERY SHOWS CLEAR SKIES ACROSS THE REGION
BUT A BLANKET OF MID LEVEL CLOUDS IS ADVANCING NORTHEASTWARD
ALONG THE GULF COAST. WINDS HAVE DIMINISHED TO NEAR CALM IN MANY
LOCATIONS BUT ARE EXPECTED TO PICK BACK UP A BIT AROUND 5 KNOTS
OR LESS FROM THE NORTHEAST AFTER MIDNIGHT. HIGH CLOUDS
ASSOCIATED WITH THE DEVELOPING STORM SYSTEM ALONG THE GULF COAST
SHOULD ARRIVE OVERNIGHT WITH LOWERING CIGS THROUGH THE DAY
TUESDAY AS MOISTURE ADVECTS INTO THE AREA FROM ALOFT.
NORTHEASTERLY WINDS PICK UP TO 5 TO 10 KNOTS THROUGH THE MORNING
HOURS AND EVENTUALLY SHIFT TO THE NORTHWEST BY LATER AFTERNOON.
SOME LIGHT SNOW IS FORECAST TO BEGIN MOVING INTO THE AREA MID
AFTERNOON BUT INITIALLY LOTS OF DRY AIR IN THE LOWER 5KFT WILL
HAVE TO BE OVERCOME SO NOT CONFIDENT IT WILL REACH CAE/CUB
BEFORE THE END OF THE PERIOD. DID GO AHEAD AND INCLUDE A MENTION
OF -SN AT AGS/DNL AFTER 20Z AND OGB 21Z WITH LOWERING CIGS TO
AROUND 5KFT BUT NO VSBY RESTRICTIONS AT THIS TIME DUE TO LOW
CONFIDENCE. THINK MOST RESTRICTIONS WILL OCCUR AROUND 00Z AND
BEYOND INTO THE EVENING AS LOWER LEVELS SATURATE FURTHER.
EXTENDED AVIATION OUTLOOK
RESTRICTIONS POSSIBLE 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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