486
FXUS62 KCAE 200120
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
820 PM EST SUN JAN 19 2025
SYNOPSIS
GUSTY WINDS EXPECTED TO SLOWLY DECREASE THIS EVENING AND
OVERNIGHT BEHIND A STRONG COLD FRONT AS VERY COLD AIR BEGINS TO
SPREAD ACROSS THE REGION. WELL BELOW NORMAL TEMPERATURES ARE
EXPECTED THROUGH THE WEEK AS AN ANOMALOUSLY DEEP TROUGH AND SURFACE
HIGH PUSHES AN ARCTIC AIR MASS INTO THE CENTRAL AND EASTERN US. ON
TUESDAY, A COASTAL LOW IS EXPECTED MOVE THROUGH ALONG THE SOUTHEAST,
LIKELY INCREASING PRECIPITATION CHANCES WITH WINTRY POTENTIAL, BUT
SOME UNCERTAINTY REMAINS.
NEAR TERM /UNTIL 6 AM MONDAY MORNING/
KEY MESSAGE(S):
- BREEZY CONDITIONS CONTINUE BUT ARE EXPECTED TO DECREASE INTO THE
OVERNIGHT HOURS.
- THE COLDEST AIRMASS SO FAR THIS SEASON IS MOVING IN TONIGHT WITH
TEMPERATURES AND DEWPOINTS FALLING RAPIDLY.
A DEPARTING LOW PRESSURE SYSTEM OFF THE NEW ENGLAND COAST AND
BUILDING HIGH PRESSURE INTO THE CENTRAL US KEEPS A FAIRLY STRONG
PRESSURE GRADIENT OVER THE REGION WHERE GUSTS TO 25 KTS HAVE STILL
BEEN OBSERVED AS A COLD FRONT NOW MOVES THROUGH THE CENTRAL MIDLANDS
TOWARD THE SW. WHILE WINDS ARE EXPECTED TO STAY NEAR 7-13 KTS
OVERNIGHT, GUSTS ARE EXPECTED TO SUBSIDE INTO THE EARLY
OVERNIGHT AS THE PRESSURE GRADIENT LOOSENS AND WE LOSE THE 25-30
KT LLJ THAT WAS IN PLACE MOST OF THE AFTERNOON. THIS WILL
LIKELY LEAD TO THE EXPIRATION OF THE LAKE WIND ADVISORY AT 11PM.
STRONG COLD ADVECTION BUILDS IN OVERNIGHT BEHIND THIS FRONT UNDER
MOSTLY CLEAR SKIES, BUT WITH WINDS REMAINING ELEVATED INTO AT LEAST
THE EARLY OVERNIGHT, A SLIGHT HINDRANCE IN TEMPERATURES FALLING
WILL BE POSSIBLE. WINDS ARE THEN EXPECTED TO BE UNDER 5-8 KTS
INTO THE EARLY MORNING HOURS AND THUS TEMPERATURES SHOULD FALL
QUICKER THEN. WITH WINDS EXPECTED TO DIMINISH FURTHER INTO THE
EARLY MORNING, TEMPERATURES SHOULD FALL INTO THE MID 20S
GENERALLY WITH SOME NORTHERN SPOTS NEARING THE LOW 20S. WIND
CHILLS ARE EXPECTED TO BE IN THE 20S MOST OF THE NIGHT BUT MAY
FALL INTO THE MID TO HIGH TEENS BRIEFLY FOR A SHORT PERIOD
AROUND DAYBREAK. THIS COULD BE CLOSE TO COLD WEATHER ADVISORY
THRESHOLDS, BUT WITH THE ISOLATED NATURE AND BRIEF DURATION, NO
HEADLINES HAVE BEEN ISSUED. VERY DRY AIR ALSO ACCOMPANIES THE
COLD AS DEWPOINTS RAPIDLY FALL INTO THE TEENS IN THE MIDLANDS BY
MORNING AND NEARING THE SINGLE DIGITS TOWARD THE UPSTATE.
SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/
KEY MESSAGE(S):
- HIGH CONFIDENCE IN THE BEGINNING OF A LONG DURATION COLD
TEMPERATURE EVENT WITH OVERNIGHT TEMPERATURES AND/OR WIND CHILL
VALUES EXPECTED TO FALL INTO THE 10F-15F RANGE.
A POTENT ARCTIC AIR MASS WILL SETTLE INTO THE EASTERN CONUS ON
MONDAY, WITH WELL BELOW NORMAL HIGH AND LOW TEMPERATURES EXPECTED.
COLD ADVECTION SHOULD CONTINUE THROUGH THE DAY UNDER CLEAR OR MOSTLY
CLEAR SKIES, WITH NORTH TO NORTHWEST WINDS IN THE 5-10 MPH RANGE
THROUGH AT LEAST MIDDAY. A PREVIOUSLY MENTIONED, THIS COULD GENERATE
A BRIEF PERIOD OF WIND CHILL VALUES THAT APPROACH COLD WEATHER
ADVISORY THRESHOLDS FOR A FEW HOURS AFTER SUNRISE. HOWEVER, ITS
BORDERLINE WITH LIMITED CONFIDENCE AND SO NO HEADLINES HAVE BEEN
ISSUED. HIGHS ARE ONLY EXPECTED TO REACH THE MID 30S NORTH TO AROUND
40 SOUTH. THEN, TEMPERATURES SHOULD BE VERY COLD MONDAY NIGHT AS
HIGH PRESSURE CONTINUES TO BUILD SOUTHEASTWARD. LOWS ON MONDAY NIGHT
ARE LIKELY TO GET DOWN INTO THE MID TO UPPER TEENS ACROSS THE
FORECAST AREA AND A COLD WEATHER ADVISORY IS LIKELY GOING TO BE
NEEDED.
LONG TERM /TUESDAY THROUGH SUNDAY/
KEY MESSAGE(S):
- MULTIPLE IMPACTFUL HAZARDS EXPECTED THIS WEEK.
1) HIGH CONFIDENCE IN A LONG DURATION COLD TEMPERATURES AS THE
COLDEST AIRMASS SINCE DECEMBER 2022 PUSHES INTO THE SOUTHEASTERN
US, LIKELY REQUIRING A LONG FUSED COLD WEATHER ADVISORY MONDAY NIGHT
INTO THURSDAY.
ARCTIC HIGH PRESSURE IS FORECAST TO CONTINUE BUILDING INTO THE AREA
TUESDAY THROUGH MUCH OF THE WEEK, BRINGING THE COLDEST AIR OF THE
SEASON TO THE AREA. LOOKING UPSTREAM, THERE ARE BITTERLY COLD
TEMPERATURES. IN FACT, CURRENT TEMPERATURES IN MINNESOTA (WHERE THIS
FORECASTER GREW UP) ARE IN THE -5 TO -10F RANGE. YES, YOU READ THAT
CORRECT, BELOW ZERO IN THE AFTERNOON. THIS IS THE AIRMASS THAT IS
EXPECTED TO MOVE INTO THE SOUTHEAST. ARE WE GOING TO BE SEEING THESE
TEMPERATURES LOCALLY? NO, BECAUSE THE AIR WILL MODIFY SOME AS IT
MOVES SOUTHEASTWARD. HOWEVER, IT GIVES AN IDEA OF THE TYPE OF
AIRMASS WE'RE DEALING WITH FOR MID TO LATE WEEK. TEMPERATURES ARE
FORECAST TO BE WELL BELOW NORMAL, WITH THE RECORD LOWS NOT OUT OF
THE QUESTION FOR THURSDAY MORNING. WITH THESE COLD TEMPERATURES IN
PLACE, WILL LIKELY BE NEEDING A LONG FUSED COLD WEATHER ADVISORY FOR
THAT TIME FRAME AS WIND CHILLS ARE LIKELY TO BE LESS THAN 15F FOR
TUESDAY, WEDNESDAY AND THURSDAY MORNINGS. DAYTIME HIGHS IN THE MID
TO LATE WEEK PERIOD ARE EXPECTED TO STRUGGLE TO GET TO 40F. WITH THE
PROLONGED PERIOD OF COLD TEMPERATURES, DANGEROUS CONDITIONS ARE
LIKELY FOR THOSE WITHOUT ADEQUATE SHELTER AND FROZEN PIPES ARE
POSSIBLE.
2) AN IMPACTFUL WINTER WEATHER SYSTEM REMAINS ON TRACK TO
AFFECT THE AREA TUES. AFTERNOON INTO WED. MORNING.
AH, THE JOYS OF FORECASTING A WINTER WEATHER SYSTEM. LATEST 12Z
GUIDANCE CONTINUES TO SUPPRESS THE FOOTPRINT OF THE HIGHER SNOW
AMOUNTS TOWARD THE COAST. HOWEVER, WE ARE STILL MODERATELY CONFIDENT
(50-70%) OF AT LEAST MINOR IMPACTS ACROSS MUCH OF THE FORECAST AREA
DUE TO THE SYSTEM. WITH THE COLD TEMPERATURES IN PLACE, CONFIDENCE
IS INCREASING THAT MOST, IF NOT ALL, THE PRECIPITATION THAT FALLS
WILL BE SNOW. CURRENT FORECAST IS ROUGHLY AN INCH NEAR THE I-95
CORRIDOR AND ABOUT HALF AN INCH ALONG THE I-20 CORRIDOR. THERE ARE
SOME CAVEATS TO THOSE AMOUNTS. THERE IS STILL A COUPLE OF DAYS
BEFORE THE SYSTEM ARRIVES, SO THERE REMAINS UNCERTAINTY IN THE EXACT
TRACK, WHICH COULD AFFECT THE AMOUNTS. ANOTHER FACTOR TO CONSIDER IS
THE AMOUNT OF DRY AIR NEAR THE SURFACE AND HOW FAST THAT SATURATES
TO ALLOW SNOW TO BEGIN TO ACCUMULATE. BECAUSE OF THIS DRY AIR, THERE
IS A GOOD CHANCE OF A SHARP CUTOFF BETWEEN ACCUMULATING SNOW AND NO
SNOW WHEN IT IS ALL SAID AND DONE.
AN ADDITIONAL FACTOR PLAYING INTO THIS SYSTEM IS HOW WELL A SOUTHERN
STREAM AND NORTHERN STREAM SHORTWAVE PHASE AS THEY MOVE TOWARD THE
REGION. GUIDANCE IS SPLIT A BIT ON THIS. THE MODEL SOLUTIONS THAT
FAVOR A PHASING OF THESE TWO FEATURES SHOW SLIGHTLY HIGHER SNOWFALL
AMOUNTS. OTHER MODEL SOLUTIONS SUGGEST THE NORTHERN STREAM WAVE
MOVES FASTER THAN THE SOUTHERN STREAM WAVE, WHICH FAVORS HIGHER
AMOUNTS FURTHER EAST. SO, THERE ARE STILL SOME DETAILS THAT NEED TO
BE IRONED OUT.
WITH THE LINGERING COLD AIR AFTER THE SYSTEM, ANY SNOW THAT DOES
ACCUMULATE WITH THIS SYSTEM IS LIKELY TO STICK AROUND FOR LONGER
THAN USUAL. SO, IMPACTS COULD LINGER FOR A FEW DAYS AFTER THE SNOW
ENDS.
AVIATION /00Z MONDAY THROUGH FRIDAY/
HIGH CONFIDENCE IN VFR CONDITIONS THROUGH THE FORECAST PERIOD
WITH GUSTY WINDS THROUGH THIS EVENING THEN SUBSIDING LATE
TONIGHT.
AN ARCTIC COLD FRONT IS SINKING SOUTHWARD THROUGH THE MIDLANDS
THIS EVENING AND THIS WILL KEEP GUSTY WINDS IN THE FORECAST
THROUGH 06Z WITH WIND DIRECTIONS TURNING MORE WEST-NORTHWESTERLY
BEHIND THE FRONT. SATELLITE IMAGERY SHOWS MOSTLY CLEAR SKIES
ACROSS THE REGION WITH SOME STRATOCUMULUS JUST SOUTHWEST OF
AGS/DNL AND MOVING THROUGH THE PEE DEE REGION BUT NOT EXPECTING
THEM TO IMPACT TERMINALS. WINDS SHOULD DECREASE TO AROUND 10
KNOTS AFTER 06Z WITH GUSTS ALSO SUBSIDING. A VERY COLD AN DRY
AIR MASS WILL SETTLE OVER THE AREA MONDAY WITH MOSTLY CLEAR
SKIES AND NORTHWESTERLY WINDS AROUND 5 TO 10 KNOTS.
EXTENDED AVIATION OUTLOOK
RESTRICTIONS POSSIBLE LATE TUESDAY
INTO TUESDAY NIGHT AS MOISTURE INCREASES AND LOW PRESSURE MOVES
NEAR THE COAST WITH SOME POSSIBLE WINTRY PRECIPITATION TUESDAY
NIGHT INTO WEDNESDAY MORNING.
CAE WATCHES/WARNINGS/ADVISORIES
SC...LAKE WIND ADVISORY UNTIL 11 PM EST THIS EVENING FOR SCZ016-018-
020>022-025>031-035-037-038-041-115-116-135>137.
GA...LAKE WIND ADVISORY UNTIL 11 PM EST THIS EVENING FOR GAZ040-
063>065-077.
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page