043
FXUS62 KCAE 191131
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
631 AM EST THU DEC 19 2024
SYNOPSIS
SHOWERS HAVE PUSHED EAST OF THE FORECAST AREA AND SOME EARLY
MORNING FOG IS POSSIBLE AS A COLD FRONT CROSSES THE AREA THIS
MORNING. THE END OF THIS WEEK LOOKS MOSTLY CLOUDY AND COOLER. A
SECOND FRONT CLEARS SKIES OUT LATE FRIDAY INTO FRIDAY NIGHT,
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):
- PATCHY FOG TO START THURSDAY, CLEARING AROUND SUNRISE.
- SHOWERS HAVE PUSHED EAST OF THE AREA. DRIER AIR IS PUSHING
INTO THE MIDLANDS THIS MORNING.
AN APPROACHING COLD FRONT IS SINKING IN FROM THE NORTHWEST THIS
MORNING. PATCHY FOG HAS DEVELOPING IN THE LULL BETWEEN THE
SHOWERS LAST EVENING AND FRONTAL ARRIVAL. THE FOG IS ERODING
STEADILY FROM THE NORTHWEST AS OF 3AM AND LIKELY WON'T LAST MUCH
PAST 5AM. A SECONDARY BACKDOOR FRONT IS ALSO DESCENDING FROM THE
NORTH THANKS TO TIGHTENING PRESSURE GRADIENT LEE OF THE
APPALACHIANS. THIS SECOND FRONT SHOULD PUSH THROUGH THIS
MORNING, SOMETIME BETWEEN 8-11AM, AND WILL BRING SOME GUSTY
WINDS OVER 20 MPH BRIEFLY AS SOME HEATING HELPS MIX DOWN
STRONGER NORTHEAST WINDS. OTHERWISE, A DRY FORECAST IS EXPECTED
TODAY WITH MOSTLY CLOUDY SKIES IN THE AFTERNOON AND HIGH TEMPS
SHOULD CLIMB TO AROUND 60 F. THE STRONGER SHOT OF COLD AND DRY
ADVECTION ARRIVES LATER TONIGHT AND INTO FRIDAY MORNING AS A
VERY SHARP SHORTWAVE DIVES TOWARDS THE AREA.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/
KEY MESSAGE(S):
- DECREASING CLOUDINESS BEHIND A COLD FRONT ON FRIDAY WITH SIMILAR
DAYTIME TEMPERATURES TO THURSDAY.
DEEP UPPER TROUGH ACROSS THE GREAT LAKES AND OHIO VALLEY WILL DRIVE
OUR WEATHER FRIDAY INTO SATURDAY. TWO SHORTWAVES WILL ROTATE AROUND
THE BASE OF THE TROUGH ON FRIDAY, ALLOWING FOR CLOUDS MUCH OF THE
DAY. A FEW LIGHT SHOWERS ARE POSSIBLE, BUT CONFIDENCE IS LOW GIVEN
LIMITED MOISTURE AVAILABILITY AND PWATS AROUND 0.5". THE BEST
CHANCES WOULD BE NORTH ALONG THE SC/NC BORDER, WHERE SOME SLIGHT
CHANCE POPS WERE INTRODUCED. DAYTIME TEMPERATURES WILL CONTINUE
THEIR COOL DOWN, WITH FORECAST HIGHS IN THE UPPER-50S NORTH AND
WEST TO LOW-60S SOUTH AND EAST. STRONGER COLD ADVECTION WILL
SETTLE IN FRIDAY NIGHT WITH SURFACE WINDS TURNING OUT OF THE
NORTHWEST. HOWEVER, RADIATIONAL COOLING MAY BE LIMITED BY THE
PRESSURE GRADIENT KEEPING THE BOUNDARY LAYER MIXED, DESPITE
CLEARING SKIES AND A DRIER AIRMASS MOVING IN. CURRENT THINKING
IS THAT TEMPERATURES WILL FALL INTO THE UPPER 20S TO MID-30S BY
DAYBREAK SATURDAY.
WITH HIGH PRESSURE BUILDING IN FROM THE WEST, SATURDAY WILL FEATURE
MOSTLY CLEAR SKIES AND TEMPERATURES ABOUT 10 DEGREES COOLER COMPARED
TO FRIDAY, GENERALLY IN THE UPPER 40S TO LOW 50S. THE TIGHT GRADIENT
WILL ALSO LEAD TO SOME BREEZY NORTHERLY WINDS, MAKING IT FEEL EVEN
CHILLIER. THIS GRADIENT DOES RELAX A BIT MORE THAT THE PREVIOUS
NIGHT THOUGH, WITH LOWS GENERALLY IN THE 20S.
LONG TERM /SUNDAY THROUGH WEDNESDAY/
KEY MESSAGE(S):
- COLD AND DRY CONDITIONS LIKELY THROUGH MONDAY.
- SEVERAL NIGHTS OF SUBFREEZING TEMPERATURES EXPECTED.
- TEMPERATURES MODERATE TOWARDS THE END OF THE PERIOD.
SUNDAY AND MONDAY ARE THE COLDEST DAYS IN THE 7 DAY FORECAST WITH A
POLAR HIGH OVER MUCH OF THE EASTERN CONUS AND GENERALLY ZONAL FLOW
ALOFT. SKIES REMAIN MOSTLY CLEAR WITH PWATS DOWN BELOW 0.3". MAIN
FORECAST CHALLENGE WILL BE ASSESSING THE NEED FOR ANY COLD WEATHER
PRODUCTS GIVEN SEVERAL NIGHTS OF SUBFREEZING TEMPERATURES. WITH HIGH
PRESSURE TO OUR NORTH AND NOT DIRECTLY OVERHEAD, SURFACE WINDS MAY
REMAIN HIGH ENOUGH TO PREVENT IDEALIZED RADIATIONAL COOLING KEEPING
VALUES ABOVE ADVISORY CRITERIA. ON THE OTHER HAND, THE MOST LIKELY
PERIOD A HEADLINE MAY BE NEEDED IS SUNDAY NIGHT INTO MONDAY MORNING,
WHEN WIND CHILL VALUES ARE FORECAST TO BE IN THE TEENS. IT SHOULD
ALSO BE MENTIONED THAT OFFICIAL FORECAST TEMPS FEATURES A BLEND OF
NBM/NBM50, GIVEN MEAN VALUES ARE ABOVE THE 75TH PERCENTILE WHICH
SEEMS TOO WARM.
ON THE UPSIDE, DAYTIME TEMPERATURES ARE LIKELY TO MODERATE EARLY
NEXT WEEK THROUGH THE HOLIDAY WITH WEAK RIDGING ALOFT. WE'LL ALSO
KEEP AN EYE ON A FEW WEAK DISTURBANCES IN THE SOUTHERN STREAM WHICH
MAY BRING INCREASING CHANCES FOR PRECIP PERHAPS ON TUESDAY AND
WEDNESDAY, BUT THE DETAILS STILL NEED TO BE WORKED OUT.
AVIATION /12Z THURSDAY THROUGH MONDAY/
MIX OF VSBY AND CIG RESTRICTIONS THROUGH 15Z THIS MORNING.
PATCHY DENSE FOG IS LINGERING ACROSS MUCH OF CENTRAL SC AND
EASTERN GA THIS MORNING AND IS CAUSING SOME PERIODIC
RESTRICTIONS FOR THE TAF'S. VSBY-CIGS DROPS TO IFR-LIFR WILL
CONTINUE AT CAE AND CUB THROUGH 13-14Z AS FOG SLOWLY CLEARS
FROM THE NORTH AND WEST. AGS AND DNL HAVE SEEN CONSISTENT
IMPROVEMENT AND ARE NOW VFR, BUT SOME STRATUS FROM THE WEST AND
AND NORTH WILL LIKELY PUSH IN BETWEEN 13-15Z BRIEFLY. OGB WILL
LIKELY LINGER PERIODICALLY IFR- LIFR ALSO UNTIL ROUGHLY 15Z.
BASED ON THE SATELLITE AND CURRENT OBS, THE TEMPO GROUP FOR
THESE RESTRICTIONS SEEMS TO BE WORKING WELL DUE TO THE SCATTERED
NATURE OF THE FOG-STRATUS. WINDS WILL SHIFT OF THE NORTHEAST
AND SCOUR OUT ANY REMAINING LOW FOG- STRATUS BY 15Z FOR THE
AREA. SOME GUSTY NORTHEAST WINDS, BRIEFLY OVER 20 MPH FOR CAE,
CUB, AND OGB ARE POSSIBLE LATER THIS MORNING AND AFTERNOON BUT
GENERALLY SUSTAINED AROUND 10 KNOT EXPECTED. VFR CONDITIONS
EXPECTED THE REST OF THURSDAY WITH BREEZY NORTHEAST WINDS
LINGERING UNTIL THURSDAY EVENING. WIDESPREAD STRATUS AND FOG
POSSIBLE AGAIN FRIDAY MORNING SO A MENTION IS INCLUDED IN THE
TAF'S TOWARDS THE END OF THE PERIOD.
EXTENDED AVIATION OUTLOOK...RESTRICTIONS POSSIBLE FRIDAY
MORNING-AFTERNOON AT CAE AND CUB WITH SOME SCATTERED SHOWERS
AROUND, OTHERWISE NO SIGNIFICANT IMPACTS TO AVIATION.
CAE WATCHES/WARNINGS/ADVISORIES
SC...NONE.
GA...NONE.
SYNOPSIS...
NEAR TERM...
SHORT TERM...
LONG TERM...
AVIATION...
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