498
FXUS62 KCAE 171928
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
228 PM EST MON FEB 17 2025
SYNOPSIS
A QUITE COOL AND DRY AIR MASS WILL SETTLE OVER THE AREA THROUGH
TUESDAY AHEAD OF A DEVELOPING LOW PRESSURE SYSTEM TO OUR WEST.
AN APPROACHING LOW FROM THE WEST WILL BRING SOME WIDESPREAD
SHOWERS WEDNESDAY, WITH SOME WINTRY PRECIP POSSIBLE ACROSS THE
NORTHERN MIDLANDS AND PEE DEE LATE WEDNESDAY. VERY COLD AND AIR
FILLS BACK IN BEHIND THIS SYSTEM FOR THE REST OF THE WEEK.
NEAR TERM /THROUGH TONIGHT/
KEY MESSAGE(S):
- COLD TEMPERATURES TONIGHT WITH LOWS NEAR FREEZING.
A COOL AND DRY AIR MASS IS SETTLING OVER THE REGION THIS
AFTERNOON. PRECIPITABLE WATER LESS THAN 0.25 INCH BASED ON
SATELLITE ESTIMATES. THE PRESSURE GRADIENT CONTINUES TO WEAKEN
AS HIGH PRESSURE BUILDS IN FROM THE NORTHWEST. TEMPERATURES THIS
AFTERNOON BELOW NORMAL BUT SHOULD MAX OUT IN THE LOW TO MID 50S
AS COLD ADVECTION WEAKENS AND DOWNSLOPE FLOW CONTINUES LEADING
TO SOME ADIABATIC WARMING.
SOMEWHAT FAVORABLE RADIATIONAL COOLING TONIGHT, WITH NEAR CALM
WINDS IN THE BOUNDARY LAYER AND RELATIVELY LOW DEW POINTS.
EXPECT TEMPS TO FALL QUICKLY THIS EVENING. BUT GUIDANCE IS
INDICATING SOME WEAK WARM ADVECTION LATE TONIGHT AND IN FAST
ZONAL FLOW ALOFT, SOME INCREASING HIGH CLOUDS, BUT MORE LIKELY
TOWARD DAWN. SO CONTINUED PREVIOUS TEMP FORECAST WITH LOWS IN
THE UPPER 20S TO LOW 30S, BUT IN COULD BE COOLER IN OUTLYING
SHELTERED AREAS.
SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/
KEY MESSAGE(S):
- WIDESPREAD SHOWERS LIKELY WEDNESDAY WITH SOME WINTRY PRECIP
POSSIBLE IN THE NORTHERN MIDLANDS AND PEE DEE.
WEAK HIGH PRESSURE WILL CONTINUE TO BUILD INTO THE AREA FROM THE
NORTHWEST TUESDAY AS A VERY STRONG SURFACE HIGH SETTLES INTO
THE CENTRAL CONUS. AS A SURFACE LOW DEVELOPS TO OUR WEST, SOME
WEAK WARM ADVECTION ALOFT WILL DEVELOP THROUGHOUT THE DAY AND
OVERSPREAD THE AREA WITH SOME MID-LEVEL CLOUD COVER. OTHERWISE,
CALM AND DRY CONDITIONS EXPECTED TUESDAY WITH TEMPS WARMING A
BIT, BACK CLOSER TO AVERAGE.
A AFOREMENTIONED SURFACE LOW WILL STEADILY PUSH EAST ACROSS THE
DEE SOUTH OVERNIGHT TUESDAY INTO WEDNESDAY MORNING. THE DRIVER
OF THIS LOW IS A WEAK SHORTWAVE THAT SPLIT OFF THE PACIFIC JET,
THEN DOVE SOUTH IN THE SOUTHWEST US. THIS SHORTWAVE HAS TRENDED
MORE AND MORE ZONAL AND DISCONNECTED FROM THE LARGE UPPER LOW
OVER THE GREAT LAKES AS IT SLIDES TOWARDS THE AREA. SO THE
SURFACE LOW IS LOOKING A BIT MORE PROGRESSIVE IN ALL THE RECENT
GUIDANCE SUITES. THE BROAD SURFACE HIGH TO THE LOW'S NORTH IS
GENERALLY ANCHORED TO THE STRONG CONFLUENCE ALOFT ON THE
WESTERN FLANK OF THIS UPPER LOW AND THEREFORE REMAINS TOO FAR
WEST TO ALLOW FOR STRONG NORTHEASTERLY FLOW INTO OUR AREA, AND
CONSEQUENTLY NO TRUE CAD IN FRONT OF THE LOW. WIDESPREAD
SHOWERS ARE LIKELY BY WEDNESDAY MORNING AS WARM ADVECTION
STRENGTHENS AHEAD OF THE LOW, BUT SURFACE TEMPS WILL BE WELL
ABOVE FREEZING. THROUGHOUT THE DAY, ASSOCIATED PRESSRUE FALLS
FROM THE LOW WITH HELP STRENGTHEN NORTHEASTERLY FLOW AND SET UP
AN IN-SITU CAD EVENT, DROPPING SURFACE TEMPS BACK TOWARDS
FREEZING BY THE AFTERNOON AND EVENING. DESPITE THE TREND TOWARDS
A LESS PHASED SHORTWAVE AND UPPER LOW, THERE WILL LIKELY BE
ENOUGH MOISTURE AROUND NORTHWEST OF THE LOW AS IT SHIFTS
OFFSHORE TO PROVIDE A PERIOD OF FREEZING RAIN OR WINTRY MIX LATE
WEDNESDAY INTO THE OVERNIGHT. BOTH SUFFICIENT MOISTURE AND COLD
ENOUGH SURFACE TEMPS WILL REMAIN NORTH OF I-20, IN THE NORTHERN
MIDLANDS AND PEE DEE. GUIDANCE IS GENERALLY IN PRETTY GOOD
AGREEMENT WITH THIS SYSTEM AT THIS POINT, WITH NEARLY ALL PIECES
SHOWING LESS THAN A 0.1" IN EXTREME NORTHERN MIDLANDS. WINTER
WEATHER ADVISORIES MAY BE NEEDED FOR THE FREEZING RAIN THREAT
ACROSS THE NORTHERN TIER, BUT NOT EXPECTING ANY WINTER PRODUCTS
FROM THE COLUMBIA METRO AND POINTS SOUTH AND WEST.
DRIER AIR WILL FILL IN QUICKLY OVERNIGHT INTO THURSDAY MORNING
AS THE LOW EXITS TO THE NORTHEAST. A COLD AIRMASS WILL FILL IN
FOR THE REMAINDER OF THURSDAY WITH HIGH TEMPS WILL BELOW
AVERAGE. THE SURFACE HIGH DRIVING THIS COLD ADVECTION WILL
REMAIN SLOW MOVING, STILL BACK ACROSS THE CENTRAL US.
LONG TERM /FRIDAY THROUGH MONDAY/
KEY MESSAGE(S):
- VERY COLD AIR WILL LINGER THROUGH THE END OF THE WEEK.
WELL BELOW AVERAGE TEMPS LIKELY THROUGH SUNDAY AS STRONG HIGH
AND ASSOCIATED AIRMASS SLOWLY SLIDES EASTWARD. EC EFI CONTINUES
TO SHOW A PRETTY IMPRESSIVE SIGNAL, ESPECIALLY TO OUR WEST, BUT
STILL A GENERALLY 0.7-0.8 EFI CONTINUES FOR US; SOT IS NEAR ZERO
HOWEVER. NAEFS IS A BIT MORE IMPRESSIVE WITH A 0.5-1ST
PERCENTILE TYPE AIRMASS. SO CONSEQUENTLY THIS IS LOOKING LIKE A
HIGHLY ANOMALOUS BUT NOT QUITE RECORD SETTING COLD. LOW TEMPS
WILL LIKELY DROP DOWN INTO TEENS FOR PARTS OF THE AREA, FRIDAY
AND SATURDAY MORNINGS; DEPENDING ON THE TRENDS, WE WILL LIKELY
APPROACH COLD WEATHER ADVISORY CRITERIA DURING THIS PERIOD.
TEMPS WILL START TO MODERATE SLOWLY OVER THE WEEKEND BACK
TOWARDS AVERAGE.
AVIATION /18Z MONDAY THROUGH SATURDAY/
VFR CONDITIONS EXPECTED THROUGH THE TAF PERIOD.
HIGH PRESSURE BUILDING IN FROM THE NORTHWEST AND THE PRESSURE
GRADIENT IS BECOMING WEAK. STILL FAVOR NORTHWEST TO NORTH WINDS
LESS THAN 10 KNOTS THROUGH THE AFTERNOON. AFTER 00Z, WINDS WILL
BE NEAR CALM AND FAVOR LIGHT EAST-SOUTHEAST AFTER 12Z TUESDAY.
SKY CLEAR THROUGH THE EVENING, SOME HIGH THIN CLOUDS TOWARD 12Z
TUESDAY.
EXTENDED AVIATION OUTLOOK... AN APPROACHING SYSTEM ON
WEDNESDAY AND THURSDAY WILL BRING SOME PRECIPITATION AND
ASSOCIATED RESTRICTIONS.
CAE WATCHES/WARNINGS/ADVISORIES
SC...NONE.
GA...NONE.
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