830
FXUS62 KCAE 211946
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
246 PM EST SAT DEC 21 2024
SYNOPSIS
STRONG HIGH PRESSURE SLIDING TO OUR NORTH BRINGS CONTINUED
CHILLY CONDITIONS INTO THE EARLY PART OF THE WEEK. BOTH DAYTIME
HIGHS AND OVERNIGHT LOWS ARE EXPECTED TO BE BELOW NORMAL INTO
MONDAY. MORE SEASONAL TEMPERATURES FOLLOW, WITH INCREASING
CHANCES FOR RAIN AS THE NEXT SYSTEM APPROACHES THE AREA.
NEAR TERM /THROUGH TONIGHT/
KEY MESSAGE(S):
- HIGH PRESSURE BUILDS AND CHILLY CONDITIONS PREVAIL.
THE BASE OF AN UPPER TROUGH HAS SHIFTED SLIGHTLY TO OUR EAST.
HOWEVER, A SHORTWAVE EMBEDDED WITHIN THIS TROUGH IS JUST ABOUT
TO REACH THE APPALACHIAN RANGE AT THIS TIME. EXPECT THIS
SHORTWAVE TO CONTINUE TRANSLATING AROUND THE BASE OF THE LARGER
SCALE TROUGH, BRINGING ANOTHER SURGE OF DRY AND COLD AIR
ADVECTION WITH IT. AT THE SURFACE, HIGH PRESSURE OVER THE MID
MISSISSIPPI VALLEY IS FORECAST TO MOVE EASTWARD, WITH ITS CENTER
MOVING OVER THE MID-ATLANTIC/NORTHEAST REGION. AS A RESULT, A
PRESSURE GRADIENT IS EXPECTED TO REMAIN OVER OUR AREA THROUGHOUT
THE DAY AND OVERNIGHT. THIS IS EXPECTED TO LEAD TO SOME BREEZY
WINDS DURING THE REST OF THE AFTERNOON AND PREVENT THE WINDS
FROM GOING TO COMPLETELY CALM OVERNIGHT. HAVING SOME WIND
OVERNIGHT WILL PREVENT IDEAL RADIATIONAL COOLING, KEEPING LOWS A
BIT WARMER THAN THEY COULD BE IF THERE WAS NO WIND. THAT SAID,
IT IS STILL EXPECTED TO BE QUITE COLD AS LOWS ARE FORECAST TO BE
IN THE MID TO UPPER 20S.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/
KEY MESSAGE(S):
- COLD AND DRY CONDITIONS LIKELY THROUGH MONDAY AFTERNOON.
- A COASTAL LOW MAY BRING THE THREAT OF PRECIPITATION MONDAY
NIGHT, ESPECIALLY ACROSS THE EASTERN MIDLANDS.
STRONG HIGH PRESSURE CENTERED IN ONTARIO AT THE START OF THE
SHORT TERM WILL MOVE EAST, PASSING OFFSHORE ON MONDAY. THIS WILL
MAINTAIN A COLD, DRY AIR MASS OVER THE FA DURING MUCH OF THE
PERIOD. SUNDAY IS EXPECTED TO BE THE COLDER OF THE TWO DAYS WITH
WELL BELOW TEMPERATURES LIKELY DURING THE DAYTIME AND OVERNIGHT
PERIODS. WHILE CONFIDENCE IN SUBFREEZING TEMPERATURES SUNDAY
NIGHT REMAINS HIGH, A COLD WEATHER ADVISORY DOES NOT APPEAR TO
BE NEEDED AS GUIDANCE HAS ONCE AGAIN TRENDED A FEW DEGREES
WARMER.
ONE CONCERN TOWARDS THE END OF THE PERIOD COMES IN THE FORM OF
A POSSIBLE COASTAL LOW SPREADING PRECIPITATION INTO OUR EASTERN
FA LATE MONDAY NIGHT. WHILE SURFACE TEMPERATURES MAY BE NEAR THE
FREEZING MARK AS PRECIPITATION IS MOVING IN, MODELED SOUNDINGS
SHOW PLENTY OF WARM AIR ALOFT, SO SNOW APPEARS UNLIKELY AT THIS
TIME. HOWEVER, WILL NEED TO MONITOR TRENDS FOR A BRIEF PERIOD
OF FREEZING RAIN DURING THE PRE-DAWN HOURS OF CHRISTMAS EVE.
LONG TERM /TUESDAY THROUGH FRIDAY/
KEY MESSAGE(S):
- ANY PRECIPITATION SHOULD END TUESDAY MORNING, AS THE COASTAL
LOW PULLS AWAY.
- NEAR NORMAL TEMPERATURES RETURN TO THE REGION, GRADUALLY
WARMING LATE IN THE WEEK.
- RAIN CHANCES INCREASE BUT CONFIDENCE REMAINS LOW.
THE PERIOD OPENS WITH THE AFOREMENTIONED COASTAL LOW PASSING TO
OUR EAST. CURRENT THINKING IS THAT ANY PRECIPITATION SHOULD
COME TO AN END TUESDAY MORNING, FOLLOWED BY PARTIAL CLEARING.
THE REMAINDER OF THE EXTENDED HAS INCREASED UNCERTAINTY AS A
SERIES OF DISTURBANCES MOVE THROUGH THE REGION. THERE WILL BE A
CHANCE OF RAIN WEDNESDAY THROUGH FRIDAY, WITH THE HIGHEST
PROBABILITY ON WEDNESDAY NIGHT AS A SHORTWAVE PASSES THROUGH.
TEMPERATURES DURING THE MID-WEEK PERIOD WILL BE WARMER, WITH
NEAR NORMAL FORECAST HIGHS TUESDAY THROUGH THURSDAY, WARMING
GRADUALLY TOWARDS THE END OF THE WEEK.
AVIATION /19Z SATURDAY THROUGH THURSDAY/
VFR CONDITIONS EXPECTED THROUGH THE TAF PERIOD.
DRY CONDITIONS EXPECTED THROUGH THE TAF PERIOD, BRINGING
GENERALLY CLEAR SKIES TO THE AREA. BREEZY NORTH/NORTHEAST WINDS
GUSTING TO 15-20 KTS THIS AFTERNOON ARE EXPECTED TO DIMINISH TO
AROUND 5 KTS OR LESS AFTER 00Z. DON'T THINK ANY TERMINAL EXCEPT
CUB WILL GO CALM FOR AN EXTENDED PERIOD OF TIME TONIGHT. WINDS
THEN SLIGHTLY INCREASE AFTER ABOUT 14Z OR 15Z.
EXTENDED AVIATION OUTLOOK...THE POTENTIAL FOR RAIN SHOWERS
AND ASSOCIATED RESTRICTIONS RETURNS FOR MIDWEEK.
CAE WATCHES/WARNINGS/ADVISORIES
SC...NONE.
GA...NONE.
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