882
FXUS62 KCAE 170835
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
335 AM EST TUE DEC 17 2024
SYNOPSIS
WARM AND DRY CONDITIONS ARE EXPECTED AS MID-LEVEL RIDGING
DEVELOPS ACROSS THE SOUTHEAST. A FRONT WITH SOME SCATTERED
SHOWERS IS EXPECTED ON WEDNESDAY, WITH A STEADY COOL DOWN
EXPECTED FOLLOWING THIS FRONT INTO THE WEEKEND. WELL BELOW
AVERAGE TEMPS ARE LIKELY SUNDAY AND INTO EARLY NEXT WEEK.
NEAR TERM /THROUGH TONIGHT/
KEY MESSAGE(S):
- DENSE FOG ADVISORY IN EFFECT FOR THE WESTERN MIDLANDS AND
NORTHERN CSRA
- DENSE FOG POSSIBLE TONIGHT ACROSS THE REMAINDER OF THE CWA
- CLEARING THROUGH THE MORNING WITH CLOUDS AND A FEW SHOWERS
POSSIBLE TONIGHT
FOG CONTINUES TO EXPAND AND BECOME INCREASINGLY DENSE IN THE
WESTERN PORTIONS OF THE FORECAST AREA AS WELL AS ALONG THE
COAST. THROUGH DAYBREAK EXPECT THE FOG TO CONTINUE EXPANDING AND
BLANKET THE ENTIRE FORECAST AREA WITH DENSE FOG ACROSS THE
WESTERN MIDLANDS AND NORTHERN CSRA WITH POTENTIAL FOR DENSE
CONDITIONS ELSEWHERE. THE DENSE FOG ADVISORY REMAINS IN EFFECT
THROUGH 8 AM FOR FAIRFIELD COUNTY SOUTH/SOUTHWEST INTO THE
NORTHERN CSRA COUNTIES. ADDITIONAL COUNTIES MAY NEED TO BE
ADDED. TEMPERATURES WILL HOLD NEARLY STEADY OR RISE SLIGHTLY AS
THE FOG BECOMES DENSE WITH OVERNIGHT LOWS GENERALLY IN THE MID
TO UPPER 40S.
WITH LIGHT WINDS EXPECTED TODAY THE FOG WILL TAKE SOME TIME TO
ERODE HOWEVER SKIES WILL BECOME PARTLY TO MOSTLY SUNNY BY LATE
MORNING. MID LEVEL RIDGING WILL AGAIN BE OVER THE REGION WITH A
COLD FRONT APPROACHING LATE TOADY AND TONIGHT. AFTERNOON HIGH
TEMPERATURES WILL RANGE FROM THE UPPER 60S IN THE WESTERN
MIDLANDS AND NORTHERN CSRA TO THE MID 70S IN THE FAR EASTERN
MIDLANDS. WITH THE FRONT NORTH OF THE FORECAST AREA TONIGHT A
FEW LIGHT SHOWERS WILL BE POSSIBLE AFTER MIDNIGHT. LOW
TEMPERATURES WILL BE IN THE LOW TO MID 50S.
SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/
KEY MESSAGE(S):
- AN APPROACHING FRONT WILL DEVELOP SOME SHOWERS AND
THUNDERSTORMS FOR WEDNESDAY. AN ISOLATED STRONG STORM CANNOT
BE RULED OUT.
- FIRST FRONT PASSES WEDNESDAY NIGHT, WITH A SECOND QUICKLY ON
ITS HEELS THURSDAY NIGHT.
REALLY INTERESTING FORECAST HAS DEVELOPED ON WEDNESDAY AS GUIDANCE
HAS TRENDED SLOWER AND DEEPER WITH THE APPROACHING TROUGH. THE
SLOWER TIMING AND DEPTH OF THE TROUGH OVERALL LOOKS POISED TO ALLOW
GREATER MOISTURE RETURN IN ADVANCE OF THE SURFACE LOW PRESSURE
SYSTEM AND FRONT ITSELF. SOUTH AND SOUTH-SOUTHWESTERLY FLOW AT THE
SURFACE AND 850 HPA SHOULD YIELD DEWPOINTS BACK UP INTO THE LOW 60S
BY WEDNESDAY AFTERNOON. LOW CLOUDS OR FOG EARLY ON WEDNESDAY SHOULD
GIVE WAY TO CUMULUS DURING THE AFTERNOON, WITH BREAKS IN THE CLOUDS
LIKELY RESULTING IN MORE SIGNIFICANT DESTABILIZATION THAT WAS
PREVIOUSLY ANTICIPATED. BOTH OPERATIONAL AND ENSEMBLE GUIDANCE HAVE
TRENDED TOWARDS SBCAPE IN THE 500-1000 J/KG RANGE BY WEDNESDAY
AFTERNOON AND EVENING. WARM AIR ADVECTION SHOWERS MAY BE SOMETHING
THAT LIMITS OVERALL DESTABILIZATION BUT THE GENERAL TREND IS TOWARDS
GREATER INSTABILITY WITHIN GUIDANCE. AND MODELS ARE SHOWING
CONVECTION DEVELOPING ALONG, AND IN ADVANCE OF, THE APPROACHING COLD
FRONT WEDNESDAY EVENING. SHEAR PROFILES ARE SUPPORTIVE OF ORGANIZED
CONVECTION, WITH 6KM BULK SHEAR FORECAST TO BE 30-40 KNOTS BY THE
TIME OF PEAK HEATING. SO THIS PAINTS THE PICTURE OF POTENTIAL STRONG
CONVECTION DURING THE AFTERNOON HOURS. NOT SURE THAT THE COVERAGE
WILL BE GREAT, BUT THE TREND DEFINITELY SUPPORTS ISOLATED STRONG TO
MARGINALLY SEVERE STORMS AHEAD OF THE FRONT. HIGHS WEDNESDAY LIKELY
WILL BE IN THE 70-75F RANGE FOR MOST. RAIN SHOWERS OR THUNDERSTORMS
ARE LIKELY TO HANG AROUND UNTIL THE FINAL PUSH OF THE FRONT
WEDNESDAY NIGHT. LOWS SHOULD BE ELEVATED DESPITE THE FRONT PASSING
THROUGH WITH LOWS IN THE UPPER 40S AND LOW 50S. ANOTHER TROUGH IS
FORECAST TO QUICKLY APPROACH ON THURSDAY, WITH SHORTWAVE RIDGING
DEVELOPING AND PASSING THROUGH THE DAY. TEMPS SHOULD BE NICE, ALBEIT
A BIT COOLER, WITH HIGHS IN THE UPPER 50S AND LOW 60S EXPECTED.
OVERNIGHT, LOOK FOR LOWS TO REMAIN ELEVATED IN THE 40S AS CLOUDS AND
ISOLATED SHOWERS DEVELOP IN ADVANCE OF THE APPROACHING SHORTWAVE
TROUGH.
LONG TERM /FRIDAY THROUGH MONDAY/
KEY MESSAGE(S):
- A GENERAL COOL DOWN IS EXPECTED THROUGH THE WEEKEND. THE
COLDEST AIR OF THE SEASON WILL LIKELY PUSH IN FOR SUNDAY AND
INTO MONDAY.
CONFIDENCE IS FAIRLY HIGH DURING THE LONG TERM. SECOND SHORTWAVE IN
AS MANY DAYS IS FORECAST TO QUICKLY APPROACH AND PUSH THROUGH THE
REGION THURSDAY NIGHT AND FRIDAY. THIS SHOULD FORCE A SURFACE LOW
OFF THE CAROLINA COASTLINE, WITH SOME SHOWERS POTENTIALLY DEVELOPING
AS THE FORCING PUSHES THROUGH EARLY ON FRIDAY. CLOUDS ARE LIKELY TO
START THE DAY BUT WILL CLEAR QUICKLY AS DRY AIR PUSHES INTO THE
REGION BEHIND THE TROUGH AND ASSOCIATED FRONT. FROM THERE,
CONFIDENCE IS HIGH IN THE FORECAST THROUGH EARLY NEXT WEEK. STRONG,
COLD HIGH PRESSURE IS FORECAST TO SHIFT INTO THE EASTERN CONUS
UNDERNEATH STRONGLY CONVERGENT MID/UPPER LEVEL FLOW THROUGH
EARLY NEXT WEEK. THIS HIGH IS FORECAST TO BE ON THE ORDER OF
1038-1040 MB AT ITS CORE, WITH A SURFACE RIDGE AXIS EXTENDING
SOUTHWARD ALONG THE APPALACHIANS. WELL BELOW NORMAL TEMPS ARE
EXPECTED WITH THIS OVER THE WEEKEND, WITH HIGHS NOT GETTING OUT
OF THE UPPER 40S OR LOW 50S SATURDAY THROUGH TUESDAY. OVERNIGHT
LOWS ARE LIKELY TO BE COLDER AND IN THE 20S. NBM50TH PERCENTILE
IS WELL BELOW THE OPERATIONAL NBM & DID A MUCH BETTER JOB WITH
THE LAST SHOT OF COLD AIR. HAVE ADDED A MIX OF NBM50/NBM FOR
LOWS IN THE LONG TERM. OVERALL, IT IS A BIT UNCERTAIN JUST HOW
COLD WE GET BECAUSE THE CENTER OF THE SURFACE HIGH IS NOT
EXPECTED TO BE DIRECTLY OVER THE AREA. THIS WILL MAKE IT TOUGH
TO GET IDEAL RADIATIONAL COOLING CONDITIONS. REGARDLESS, THE
AIRMASS IS FORECAST TO BE VERY COLD, SO BE SURE TO TAKE EXTRA
PRECAUTIONS TO PROTECT PIPES IF YOU ARE TRAVELING IN ADVANCE OF
THE CHRISTMAS HOLIDAY NEXT WEEK. ADDITIONALLY, IT DOES LOOK LIKE
WE COULD BE COLD ENOUGH TO APPROACH OUR CRITERIA FOR NEW 2024
COLD WEATHER PRODUCTS, SO KEEP YOUR EYE ON THE FORECAST FOR THE
LATEST!
AVIATION /09Z TUESDAY THROUGH SATURDAY/
IFR TO LIFR RESTRICTIONS EXPECTED AFTER 06Z DUE TO DENSE FOG
DEVELOPMENT.
SATELLITE IMAGERY AND SURFACE OBS SHOW FOG CONTINUING TO EXPAND
AND THICKEN WEST AND EAST OF THE TAF SITES. THROUGH DAYBREAK
EXPECT FOG AND LOW CIGS AT ALL TERMINALS WITH LIFR RESTRICTIONS
FROM THE EARLY MORNING THROUGH SUNRISE. WITH MIXING THIS MORNING
CONDITIONS WILL IMPROVE WITH ALL SITES RETURNING TO VFR BY 15Z.
MOSTLY TO PARTLY SUNNY SKIES THIS AFTERNOON WILL GIVE WAY TO
INCREASING CLOUDS NEAR THE END OF THE PERIOD AS A FRONTAL
BOUNDARY NORTHWEST OF THE AREA. WINDS THROUGH THE PERIOD WILL BE
VARIABLE AT 5 KNOTS OR LESS.
EXTENDED AVIATION OUTLOOK...POTENTIAL FOR SHOWERS AND ASSOCIATED
RESTRICTIONS WEDNESDAY AND WEDNESDAY NIGHT.
CAE WATCHES/WARNINGS/ADVISORIES
SC...DENSE FOG ADVISORY UNTIL 8 AM EST THIS MORNING FOR SCZ018-020-
021-025-026.
GA...DENSE FOG ADVISORY UNTIL 8 AM EST THIS MORNING FOR GAZ040-063-
064.
SYNOPSIS...
NEAR TERM...
SHORT TERM...
LONG TERM...
AVIATION...
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