217
FXUS62 KCAE 220027
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
727 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 /UNTIL 6 AM SUNDAY MORNING/
KEY MESSAGE(S):
- HIGH PRESSURE BUILDS AND CHILLY CONDITIONS PREVAIL.
WITH AN UPPER TROUGH CONTINUING TO PUSH THROUGH THE AREA AND
NORTHWEST FLOW DEVELOPING BEHIND IT, DEEP LAYER DRY AIR IS
PUSHING OVER THE FORECAST AREA WITH SATELLITE DERIVED PWATS
AROUND A QUARTER OF AN INCH. AS THE SURFACE HIGH, WHICH REMAINS
OVER THE GREAT LAKES, BUILDS SOUTHEAST TOWARDS THE MID-ATLANTIC,
WINDS WILL INCREASE A BIT OUT OF THE NORTH OVERNIGHT. THIS WILL
PREVENT IDEAL RADIATIONAL COOLING OVERNIGHT BUT STILL COLD
ADVECTION WILL PROMOTE LOWS DROPPING INTO THE MID TO UPPER 20S.
SHORT TERM /6 AM SUNDAY MORNING 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 SATURDAY/
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 /00Z SUNDAY THROUGH THURSDAY/
HIGH CONFIDENCE VFR CONDITIONS EXPECTED THROUGH THE TAF PERIOD.
A REINFORCING SHOT OF COLD AND DRY AIR WILL BUILD INTO THE AREA
TONIGHT AS AN UPPER TROUGH CROSSES THE REGION. THE DRY AIR MASS
AND ELEVATED WINDS OVERNIGHT SHOULD PREVENT ANY FOG/STRATUS
CONCERNS. WINDS WILL BE FROM THE NORTH TO NORTHEAST AROUND 4 TO
7 KNOTS OVERNIGHT THEN PICK UP FROM THE NORTHEAST AROUND 6 TO 9
KNOTS BY 14Z INTO THE AFTERNOON HOURS UNDER MOSTLY CLEAR SKIES.
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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