782
FXUS62 KCAE 181837
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
137 PM EST TUE FEB 18 2025
SYNOPSIS
MOISTURE WILL SLOWLY INCREASE TONIGHT AHEAD OF A DEVELOPING LOW
PRESSURE SYSTEM IN THE WESTERN GULF. THE LOW WILL TRACK EAST
ALONG THE GULF COAST WITH RE-DEVELOPMENT OFF THE COAST OF SC.
THIS WILL LEAD TO WIDESPREAD RAIN WEDNESDAY WITH SOME WINTRY
PRECIP POSSIBLE ACROSS THE NORTHERN MIDLANDS AND PEE DEE. WITH
LINGERING MOISTURE ON THURSDAY AND VERY COLD AIR SPREADING IN
FROM THE NORTHWEST ON STRONG GUSTY WINDS, A FEW SNOW SHOWERS ARE
POSSIBLE MAINLY IN THE NORTH/CENTRAL MIDLANDS. A VERY COLD AIR
MASS WILL SETTLE OVER THE AREA BY FRIDAY MORNING WITH
TEMPERATURES WELL BELOW NORMAL.
NEAR TERM /THROUGH TONIGHT/
KEY MESSAGE(S):
- NEAR NORMAL TEMPERATURES WITH INCREASING MID AND HIGH LEVEL
CLOUDS.
UPPER LEVEL TROUGH IN THE ROCKY MOUNTAINS/DESERT SOUTHWEST
REGIONS WILL BE MOVING EAST INTO THE MISSISSIPPI VALLEY BY
MORNING. AHEAD OF THE TROUGH, MID AND HIGH LEVEL CLOUDS WILL
INCREASE OVERNIGHT ASSOCIATED WITH SUB- TROPICAL JET IN SOUTH-
WESTERLY FLOW ALOFT. THE AIR MASS ACROSS THE AREA REMAINS DRY
AT THE MOMENT WITH PRECIPITABLE WATER 0.5 INCH OR LESS. A VERY
STRONG HIGH PRESSURE AREA IS CENTERED OVER THE NORTHERN
MIDLANDS. THIS RIDGE IS EXTENDING SOUTHEAST INTO THE
SOUTHEASTERN STATES. THE RIDGING OVER THE AREA WILL WEAKEN
TONIGHT AS WEAK LOW PRESSURE DEVELOPS IN THE WESTERN GULF. LOW-
LEVEL MOISTURE FLUX APPEARS TO INCREASE AFTER MIDNIGHT TONIGHT,
MAINLY IN THE EAST. SO KEPT A DRY FORECAST OVERNIGHT WITH
TEMPERATURES FALLING INTO THE MID TO UPPER 30S.
SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/
KEY MESSAGE(S):
- WIDESPREAD SHOWERS LIKELY WEDNESDAY WITH SOME WINTRY PRECIP
POSSIBLE IN THE NORTHERN MIDLANDS AND PEE DEE.
- VERY COLD TEMPERATURES EXPECTED ON THURSDAY AND THURSDAY
NIGHT.
AN ACTIVE SHORT TERM PERIOD, CENTERED ON WEDNESDAY AND WEDNESDAY
NIGHT, IS EXPECTED. EXPANSIVE SYNOPTIC SCALE SYSTEM IS FORECAST TO
BE SET UP ACROSS THE EASTERN 2/3RDS OF THE CONUS, WITH THE OVERALL
SYSTEM SLOWLY AMPLIFYING THROUGH THE DAY ON WEDNESDAY. SOUTHEASTERN
US WILL BE SQUARELY WITHIN THE INFLUENCE OF THIS UPPER TROUGH, WITH
THE RIGHT-ENTRANCE REGION OF THE UPPER-LEVEL JET STREAK TRANSLATING
EASTWARD AND OFF SHORE BY THURSDAY MORNING. MEANWHILE, INTENSE
CONVERGENCE OVER THE NORTH-CENTRAL PLAINS IS EXPECTED TO FOSTER A
VERY INTENSE, COLD SURFACE HIGH PRESSURE SYSTEM THAT SHOULD SHIFT
SOUTH AND EASTWARD. THE CENTER OF THIS HIGH IS FORECAST TO HAVE
PRESSURES ON THE ORDER OF 1052-1056 MB, WHICH IS 3-3.5 STANDARD
DEVIATIONS ABOVE NORMAL FOR THIS TIME OF YEAR. SO THIS IS EXPECTED
TO BE QUITE THE COLD AIRMASS, AND IT IS FORECAST TO CONTINUE
EXERTING INCREASING INFLUENCE ACROSS THE EASTERN US THROUGH THE
PERIOD. COLDER THAN NORMAL TEMPERATURES ARE FORECAST TO BE IN PLACE
AS A COASTAL SURFACE LOW DEVELOPS ACROSS THE GULF COAST AND SHIFTS
EASTWARD OFF THE COAST OF NC BY WEDNESDAY EVENING.
MOISTURE SHOULD RAPIDLY INCREASE ACROSS THE AREA ON WEDNESDAY
MORNING AS ALL OF THE LIFT APPROACHES AND OVERSPREADS THE AREA,
YIELDING SHOWERS BY LATE WEDNESDAY MORNING OR EARLY WEDNESDAY
AFTERNOON. DESPITE THE STRENGTH OF THE SURFACE HIGH MOVING INTO THE
LOWER 48, IT DOESN'T LOOK TO BE EAST ENOUGH TO SUPPORT WINTRY
WEATHER AT THE ONSET OF PRECIPITATION ACROSS THE NORTHERN FORECAST
AREA. INSTEAD, GUIDANCE FORECASTS TEMPERATURES IN THE MID 30S AT THE
ONSET OF PRECIPITATION, WITH TEMPERATURES GRADUALLY FALLING VIA
SURFACE COLD AIR ADVECTION AS THE COASTAL LOW INTENSIFIES THROUGH
THE DAY ON WEDNESDAY. REALLY, OUTSIDE OF THE PEE DEE REGION OF OUR
FORECAST AREA, PRECIPITATION SHOULD REMAIN LIQUID THROUGHOUT THE
EVENT. AND EVEN WHERE TEMPERATURES DO FALL NEAR OR BELOW FREEZING &
FOSTER WINTRY WEATHER, AMOUNTS LOOK FAIRLY LIGHT. GUIDANCE KIND OF
"SKIPS" OUR AREA WITH THE BEST QPF FALLING TO OUR WEST, SOUTH, AND
EAST/NORTHEAST. THIS OWES IN PART TO THE WAY THE JET STREAKS PHASE
AS THE SYSTEM PUSHES THROUGH, AND ALSO WHERE THE BEST ISENTROPIC
LIFT DEVELOPS AND HOW IT DEVELOPS. EVEN THE MOST AGGRESSIVE MODEL,
THE NAM, TAKES THE BEST ISENTROPIC LIFT AND WARM ADVECTION TO OUR
NORTHEAST FAIRLY QUICKLY ON WEDNESDAY, WITH ONLY LIGHT SHOWERS
EXPECTED ACROSS OUR AREA. A BATCH OF HEAVIER PRECIP IS EXPECTED TO
REDEVELOP ON WEDNESDAY EVENING AS THE COASTAL LOW STRENGTHENS AND
WARM ADVECTION FOSTERS MORE FRONTOGENESIS CLOSER TO IT. HOWEVER, THE
LOW AND ASSOCIATED FORCING SHOULD BEGIN DEPARTING OUR
EASTERN/NORTHEASTERN FORECAST AREA SHORTLY AFTER THIS, LIMITING
OVERALL PRECIPITATION AMOUNTS. LATEST HREF GUIDANCE IS IN GOOD
AGREEMENT WITH THE GLOBAL MODELS SHOWING A GENERAL 0.1"-0.3" OF
TOTAL QPF ACROSS THE FORECAST AREA, WITH THE GREATEST PROBABILITY OF
>0.25" IN THE PEE DEE REGION. EVEN IF ALL OF THIS FELL WITH TEMPS
BELOW FREEZING, IT WOULD BE TOUGH TO GET TO ANYTHING MORE THAN
WINTER WEATHER ADVISORY CRITERIA.
THIS BRINGS US TO THE OTHER QUESTION: PRECIPITATION TYPE. THIS IS
TYPICALLY A FREEZING RAIN SETUP, AND WHILE THAT REMAINS THE MOST
LIKELY SCENARIO, GUIDANCE HAS TRENDED A BIT COOLER WITH LOW-LEVEL
TEMPS BY WEDNESDAY EVENING. THIS IS A RESULT OF THE OVERALL SYSTEM
BEING A BIT WEAKER & BETTER FORCING BEING CONFINED TO OUR EAST, WITH
WARM ADVECTION IN THE 925-850 HPA LAYER BEING WEAKER AS RESULT. IF
THIS PLAYED OUT, IT WOULD RESULT IN MORE OF A SLEET THAN FREEZING
RAIN BEING THE PRIMARY P-TYPE. REGARDLESS, IT DOES LOOK LIKELY THAT
OUR NORTHERN TIER OF COUNTIES ALONG THE NC/SC BORDER SHOULD SEE A
FEW HOURS OF WINTRY MIX ON WEDNESDAY EVENING. AS PREVIOUSLY
MENTIONED, TOTALS LOOK PRETTY LIGHT, WITH TOTAL ACCUMULATIONS OF
ANYTHING GENERALLY ADDING UP TO LESS THAN 0.1". THIS COULD STILL BE
IMPACTFUL, AND AS A RESULT, A WINTER WEATHER ADVISORY MAY BE NEEDED
AT A LATER TIME. AS PREVIOUSLY MENTIONED, THE COLUMBIA AND AUGUSTA
METRO AREAS & AREAS SURROUNDING SHOULD REMAIN ALL LIQUID.
THIS SYSTEM IS FORECAST TO EXIT STAGE RIGHT ON THURSDAY WITH COLD
ADVECTION CONTINUING THROUGH THE DAY AS THE STRONG SURFACE HIGH
MAKES ITS WAY SOUTH AND EAST. WE GENERALLY LOOK TO REMAIN DRY AND
BREEZY, BUT SOME GUIDANCE DOES CONTINUE TO SHOW SOME ISOLATED
RAIN/SNOW SHOWERS ALONG A SECONDARY FRONT MOVING THROUGH IN THE LATE
MORNING OR EARLY AFTERNOON. THIS SEEMS PRETTY UNLIKELY WITH A VERY
DRY AIRMASS MOVING IN, BUT IF ANYTHING DOES OCCUR, IT SHOULD REMAIN
NOTHING MORE THAN A NUISANCE. THE BIGGEST STORY ON THURSDAY WILL
BE THE FRIGID TEMPERATURES. OUR NORMAL HIGH AT CAE IS 62F AND
NORMAL LOW IS 37F. HOWEVER, ON THURSDAY, WE ARE LOOKING AT BEING
15-20F BELOW NORMAL FOR BOTH. EFI CONTINUES TO POINT TOWARDS
ANOMALOUS BUT NOT RECORD COLD WITH VALUES SOLIDLY IN THE -0.8 TO
-0.9 RANGE. SO LOOK FOR HIGHS IN THE LOW TO MID 40S AND LOWS IN
THE LOW 20S!
LONG TERM /FRIDAY THROUGH TUESDAY/
KEY MESSAGE(S):
- COOLER THAN NORMAL TEMPERATURES TO CONTINUE INTO THE WEEKEND
BEFORE A SLOW WARM UP.
THANKFULLY, THE LONG TERM PERIOD LOOKS TO BRING QUIETER WEATHER
THAN WE HAVE SEEN OVER THE PAST COUPLE OF WEEKS. BEHIND
WED/THUR SYSTEM, STRONG SURFACE HIGH PRESSURE SHOULD CONTINUE TO
FOLLOW STRONG MID/UPPER LEVEL CONVERGENCE AS TROUGHING SHIFTS
EASTWARD TOWARDS THE EAST COAST. GUIDANCE IS IN GOOD AGREEMENT
THAT TEMPS WILL CONTINUE TO BE WELL BELOW NORMAL ON FRIDAY AND
FRIDAY NIGHT AS THE CENTER OF THE SURFACE HIGH SHIFTS TOWARDS
US. IT WOULDN'T BE SURPRISING IF FRIDAY NIGHT IS AS COLD AS
THURSDAY NIGHT GIVEN THE POTENTIAL FOR IDEAL RADIATIONAL COOLING
CONDITIONS, SO EXPECT LOWS IN THE LOW TO MID 20S. TEMPERATURES
THE LOOK TO BEGIN MODERATING AS WE HEAD TOWARDS EARLY NEXT WEEK.
ENSEMBLES AND OPERATIONAL MODELS SHOW A POTENTIAL GLANCING BLOW
FROM A SHORTWAVE ON SUNDAY BUT DIFFER ON THE AMPLITUDE OF THAT
SYSTEM, WITH ENSEMBLES GENERALLY SHOWING LOWISH CHANCES FOR
MEASURABLE RAINFALL AT THIS POINT. TEMPS SHOULD BE BACK INTO THE
UPPER 50S, WITH HIGHS CLIMBING BACK NEAR NORMAL VALUES BY
MONDAY AND TUESDAY AS THE PATTERN SHIFTS TOWARDS BENIGN
TROUGHING AND WEAK SURFACE HIGH PRESSURE.
AVIATION /18Z TUESDAY THROUGH SUNDAY/
HIGH CONFIDENCE IN VFR CONDITIONS THROUGH AT LEAST 09Z
WEDNESDAY. RESTRICTIONS EXPECTED AFTER 12Z WEDNESDAY.
HIGH PRESSURE EXTENDING INTO THE AREA FROM THE NORTHWEST. LOW-
LEVEL MOISTURE REMAINS LIMITED. MID AND HIGH LEVEL CLOUDS WILL
INCREASE TONIGHT IN SOUTH-WESTERLY FLOW ALOFT AHEAD OF AN UPPER
TROUGH MOVING INTO THE CENTRAL U.S. WINDS WILL BE VARIABLE BUT
FAVOR EAST-NORTHEAST DIRECTION THROUGH TONIGHT. GUIDANCE IS
SUGGESTING MVFR CEILINGS DEVELOPING IN THE MORNING, MAINLY AFTER
12Z. RAIN WILL BE DEVELOPING FROM EAST-CENTRAL GA INTO CENTRAL
SC DURING THE MID TO LATE MORNING. THIS MAY REDUCE VISIBILITIES.
RAIN IS EXPECTED TO BE LIGHT SO MVFR VISIBILITIES MORE LIKELY.
EXTENDED AVIATION OUTLOOK...LOW PRESSURE ALONG THE GULF COAST,
MOVING TO OFF THE COAST OF SC WILL RESULT IN PRECIPITATION AND
RESTRICTIONS THROUGH THURSDAY MORNING. STRONG GUSTY NORTHWEST
WINDS EXPECTED THURSDAY AFTERNOON.
CAE WATCHES/WARNINGS/ADVISORIES
SC...NONE.
GA...NONE.
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