622
FXUS62 KCAE 191902
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
202 PM EST THU DEC 19 2024
SYNOPSIS
THE END OF THIS WEEK LOOKS MOSTLY CLOUDY AND COOLER. A COLD
FRONT CLEARS SKIES OUT FRIDAY INTO FRIDAY NIGHT, WITH BREEZY
CONDITIONS POSSIBLE LATER IN THE DAY. THIS WILL BE FOLLOWED BY
SEVERAL DAYS OF COLD WEATHER WITH SUBFREEZING TEMPERATURES AT
NIGHT. A WARMING TREND IS EXPECTED TOWARDS CHRISTMAS ALONG WITH
THE NEXT CHANCE OF RAIN.
NEAR TERM /THROUGH TONIGHT/
KEY MESSAGE(S):
- CONSIDERABLE CLOUDS AND COOLER TONIGHT.
SURFACE COLD FRONT HAS MOVED OFFSHORE, WITH LINGERING TROUGH TO
THE NORTHWEST ALONG THE SAVANNAH RIVER AREA. SATELLITE IS
SHOWING CONSIDERABLE LOW CLOUDS ACROSS THE REGION AND TEMPS
RANGING FROM THE MID 50S IN THE CLOUDY AREAS TO THE MID 60S IN
THE BREAKS IN THE OVERCAST., MAINLY IN THE SOUTHEAST MIDLANDS.
THIS IS BEING CAUSED BY WEAK MOISTURE FLUX OFF THE ATLANTIC AND
RESULTING SHALLOW ISENTROPIC LIFT. ALTHOUGH THE DEEPER MOISTURE
IS MOVING OUT OF THE REGION AS THE AMPLIFIED UPPER TROUGH TO THE
EAST, THE LOW CLOUDINESS IS LIKELY TO PERSIST THROUGH THE
OVERNIGHT HOURS. A CLIPPER SYSTEM IN THE UPPER MIDWEST THIS
AFTERNOON WILL DIVE SOUTHEAST TOWARD THE OHIO VALLEY. AS THE
UPPER TROUGH AMPLIFIES INTO THE SOUTHEAST CONUS LATE TONIGHT, A
SHORT WAVE TROUGH WILL BE APPROACHING FROM THE WEST. MOISTURE IS
QUITE SHALLOW, AND PRECIPITABLE VERY LOW, LESS THAN 0.6 INCH.
SOME OF THE CAMS SUGGEST A FEW WIDELY SCATTERED LIGHT SHOWERS
TOWARD DAYBREAK. KEPT A DRY FORECAST THROUGH 12Z, ANY SHOWERS
SHOULD BE BRIEF AND QUITE LIGHT. TEMPERATURES SHOULD STILL BE
COOLER THAN PREVIOUS NIGHT DUE TO WEAK SHALLOW COLD ADVECTION
AND EXPECT LOW TEMPS IN THE 40S.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/
KEY MESSAGE(S):
- DECREASING CLOUDINESS BEHIND A COLD FRONT ON FRIDAY WITH
SIMILAR DAYTIME TEMPERATURES TO TODAY.
- BREEZY CONDITIONS POSSIBLE BEHIND THE FRONT. A LAKE WIND
ADVISORY MAY BE NEEDED IF TRENDS CONTINUE.
- NOTICEABLY COLDER ON SATURDAY WITH SUBFREEZING TEMPERATURES
AT NIGHT.
A SERIES OF SHORTWAVE TROUGHS WILL BE MOVING THROUGH THE REGION
DURING THE PERIOD. AT THE SURFACE, A CLIPPER SYSTEM WILL MOVE
FROM INDIANA SOUTHEAST INTO NORTH CAROLINA ON FRIDAY, WITH A
COLD FRONT CLEARING OUT THE PERSISTENT CLOUD COVER OVER THE FA
FROM SOUTHWEST TO NORTHEAST. THE PASSAGE OF THE FIRST SHORTWAVE
ON FRIDAY COULD TRIGGER ISOLATED SHOWERS BUT WITH LIMITED
MOISTURE CONFIDENCE IS LOW, LESS THAN 20 PERCENT, WITH THE
HIGHEST PROBABILITIES ACROSS OUR NORTHERNMOST COUNTIES. GIVEN
THE STRONGER WINDS ALOFT, BREEZY CONDITIONS MAY DEVELOP BEHIND
THE COLD FRONT AND COULD REQUIRE A LAKE WIND ADVISORY FOR AT
LEAST THE CSRA WITH THE NEXT FORECAST PACKAGE. DAYTIME
TEMPERATURES WILL BE SIMILAR ACROSS THE NORTHERN MIDLANDS AND
5-10 DEGREES COOLER IN THE SOUTHERN MIDLANDS AND CSRA. WITH
CLEAR SKIES AND COLD AIR ADVECTION, TEMPERATURES WILL FALL INTO
THE UPPER 20S TO LOWER 30S BY DAYBREAK ON SATURDAY.
THE COOLING TREND CONTINUES INTO SATURDAY AS HIGH PRESSURE
BUILDS IN FROM THE WEST, WEAKENING THE PRESSURE GRADIENT.
HAVING SAID THAT, WINDS MAY START OFF ON THE BREEZY SIDE MAKING
TEMPERATURES FEEL EVEN COLDER. THIS WILL BE THE FIRST OF SEVERAL
DAYS OF BELOW NORMAL TEMPERATURES. CONDITIONS WILL BE MORE
FAVORABLE FOR RADIATIONAL COOLING SATURDAY NIGHT, ALLOWING
TEMPERATURES TO FALL INTO THE 20S. EVEN COLDER TEMPERATURES ARE
EXPECTED THE FOLLOWING NIGHT.
LONG TERM /SUNDAY THROUGH WEDNESDAY/
KEY MESSAGE(S):
- SUNDAY AND MONDAY ARE THE COLDEST DAYS OF THE PERIOD, FOLLOWED
BY A WARMING TREND.
- THE NEXT STORM SYSTEM ARRIVES AROUND CHRISTMAS DAY.
SURFACE HIGH PRESSURE WILL PASS TO OUR NORTH ON SUNDAY AND
MONDAY, MAINTAINING A COLD, DRY AIR MASS OVER THE REGION.
TEMPERATURE AND MOISTURE ADVECTION OCCURS TUESDAY AND WEDNESDAY
AS THE HIGH MOVES OFFSHORE AND THE NEXT STORM SYSTEM APPROACHES.
CONFIDENCE REMAINS HIGH THAT THERE WILL BE SEVERAL DAYS OF BELOW
NORMAL TEMPERATURES, FALLING BELOW FREEZING EACH NIGHT. THE
PERIOD OF GREATEST CONCERN REMAINS SUNDAY NIGHT WHEN WIND CHILL
VALUES COULD APPROACH COLD WEATHER ADVISORY CRITERIA ACROSS
PORTIONS OF THE CWA. REGARDLESS OF WHETHER ADVISORY CRITERIA IS
MET, IT IS IMPORTANT THAT COLD WEATHER PREPARATIONS ARE MADE
AHEAD OF TIME, ESPECIALLY FOR THOSE WHO WILL NOT BE HOME DURING
THIS PERIOD. TEMPERATURES AND PWATS INCREASE DURING THE MIDDLE
OF NEXT WEEK, BUT AN APPROACHING STORM SYSTEM WILL BRING THE
CHANCE FOR RAIN AROUND CHRISTMAS DAY. TIMING OF THIS SYSTEM IS
LOW SO IT IS NOT A GUARANTEE THAT CHRISTMAS WILL BE WET.
AVIATION /18Z THURSDAY THROUGH TUESDAY/
MVFR CEILINGS EXPECTED THROUGH THE AFTERNOON INTO THE EVENING.
IFR CEILINGS LATE TONIGHT.
WIDESPREAD MVFR STRATO-CUMULUS WILL CONTINUE ACROSS THE REGION
AS SHALLOW MOISTURE ADVECTS INLAND FROM THE ATLANTIC. THE
GUIDANCE IS INDICATING THE CEILINGS MAY LOWER LATE TONIGHT TO
IFR. FOG IS POSSIBLE TONIGHT GIVEN DRY AIR ALOFT, BUT LOW CLOUDS
LIKELY TO BE IN PLACE THROUGH THE OVERNIGHT. SO THINK FOG THREAT
LOWER THAN PREVIOUS NIGHT AND KEPT VISIBILITY AT MVFR LEVELS.
LOW CLOUDS EXPECTED TO MIX OUT EARLIER IN THE AGS/DNL THAN
CAE/CUB TERMINAL AREA FRIDAY MORNING AROUND 12Z-14Z. WINDS WILL
BE NORTH TO NORTHEAST 5 TO 10 KNOTS, DIMINISHING TO LIGHT
NORTHEAST OVERNIGHT.
EXTENDED AVIATION OUTLOOK...NO SIGNIFICANT IMPACTS TO AVIATION.
CAE WATCHES/WARNINGS/ADVISORIES
SC...NONE.
GA...NONE.
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