985
FXUS62 KCAE 151919
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
219 PM EST WED JAN 15 2025
SYNOPSIS
DRY CONDITIONS ARE EXPECTED THROUGH THE END OF THE WEEK, THEN
SHOWERS LIKELY THIS WEEKEND AS A LOW PRESSURE SYSTEM CROSSES
INTO THE EASTERN US. BEHIND THE SYSTEM, EXPECT WELL BELOW
NORMAL TEMPERATURES AS A ANOMALOUSLY DEEP TROUGH AND SURFACE
HIGH PUSHES AN ARCTIC AIR MASS INTO THE CENTRAL AND EASTERN US.
BY THE MIDDLE OF NEXT WEEK, A COASTAL LOW WILL LIKELY INCREASE
PRECIP CHANCES WITH SOME WINTRY POTENTIAL POSSIBLE.
NEAR TERM /THROUGH TONIGHT/
KEY MESSAGE(S):
- DRY HIGH PRESSURE WILL BUILD INTO THE REGION THROUGH TONIGHT
REMAINDER OF THIS AFTERNOON: SURFACE FRONT JUST SOUTH OF THE
FORECAST AREA WILL CONTINUES TO PUSH FURTHER SOUTHWARD. WINDS
OUT OF THE NORTH WILL BRING ADDITIONAL DRIER AIR INTO THE AREA,
WITH SINGLE DIGIT DEWPOINTS EXPECTED ACROSS THE NORTHERN
MIDLANDS AND PEE DEE LATE THIS AFTERNOON. DEWPOINTS REMAINING
HIGHER OVER THE SOUTHERN MIDLANDS AND CSRA. TEMPERATURES HAVE
JUST ABOUT TOPPED OUT IN THE NORTHERN MIDLANDS WITH COLD
ADVECTION MOVING IN. HIGHS ONLY IN THE LOWER 40S FOR THE
REMAINDER OF THE DAY, WITH POTENTIAL FOR FALLING TEMPERATURES
LATER IN THE AFTERNOON. SOUTHERN MIDLANDS AND CSRA WILL SEE
AFTERNOON HIGHS INTO THE LOW TO MIDDLE 50S.
TONIGHT: HIGH PRESSURE CONTINUES PUSHING INTO THE AREA. WINDS
SHOULD DIMINISH AND BECOME NEARLY CALM AFTER SUNSET. WITH HOW
DRY THE AIRMASS IS, ALONG WITH MOSTLY CLEAR SKIES, IDEAL
RADIATIONAL COOLING SHOULD SET UP OVERNIGHT. DID GO ON THE
COOLER SIDE OF THE BLEND THROUGH THE NIGHT, WHICH BRINGS LOWS
INTO THE LOWER 20S ACROSS THE NORTH IN AREAS ASSOCIATED WITH
MUCH DRIER AIR. ACROSS THE SOUTH, READINGS AROUND 30 TO THE
UPPER 20S EXPECTED TO OCCUR.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/
KEY MESSAGE(S):
- DRY AND BREEZY THURSDAY, WITH CALM HIGH PRESSURE BUILDING IN
FOR FRIDAY.
HIGH PRESSURE WILL SHIFT EASTWARD OVERNIGHT INTO THURSDAY
MORNING. A SERIES OF QUICK MOVING SHORTWAVES EMBEDDED IN THE
NORTHWEST FLOW ALOFT WILL PUSH THROUGH THURSDAY AS THE SURFACE
HIGH SHIFTS EAST OF THE AREA. AN ASSOCIATED SURFACE FRONT WILL
APPROACH THE AREA LATE THURSDAY INTO FRIDAY. THE MAIN SENSIBLE
WEATHER IMPACT WILL BE GUSTY WINDS THROUGHOUT THE AFTERNOON;
BORDERLINE LAKE WIND ADVISORY CRITERIA BASED ON WHEN THE FRONT
ARRIVES AND IF WE MAINTAIN DEEP BOUNDARY LAYER MIXING. GUIDANCE
BROADLY SHOWS GUSTS UP AROUND 30 MPH, BUT THIS ASSUMES VERY
EFFICIENT MIXING WHICH WILL DEPEND ON THE TIMING OF THE FRONT.
FOLLOWING THE SHORTWAVES ALOFT, HIGH PRESSURE ANCHORED TO THE
BROAD RIDGE AXIS AND STRONG CONFLUENCE TO OUR NORTH WILL PUSH
BACK INTO THE AREA FOR FRIDAY. SO CLEAR, COOL, AND CALM WEATHER
EXPECTED AHEAD OF THE NEXT SYSTEM OVER THE WEEKEND.
LONG TERM /SATURDAY THROUGH WEDNESDAY/
KEY MESSAGE(S):
- WIDESPREAD MODERATE-HEAVY RAIN LIKELY SATURDAY AHEAD OF A VERY
STRONG COLD FRONT. TEMPS QUICKLY FALL THROUGHOUT SUNDAY AND
INTO MONDAY WITH THE COLDEST AIRMASS OF THE SEASON MOVING IN.
- CONFIDENCE REMAINS LOW IN ANYTHING SPECIFIC ABOUT THE
POSSIBLE WINTRY PRECIP NEXT WEEK.
A STRONG SOUTHERN STREAM SHORTWAVE WILL LIFT OUT OF THE
SOUTHWEST CONUS AND PUSH ACROSS THE GOM COAST BY SATURDAY.
PRETTY IMPRESSIVE CYCLOGENESIS AND SYNOPTIC FORCING WILL
DEVELOP ACROSS THE SOUTHEAST US AHEAD OF THIS SHORTWAVE AS THE
SOUTHERN AND NORTHERN STREAM JETS PHASE. ASSOCIATED IVT AND
SOUTHERLY MOISTURE ADVECTION WILL OVERSPREAD AHEAD OF THE
SHORTWAVE INTO SATURDAY, BUT THE EXTREMELY DRY AIRMASS AHEAD OF
THE FRONT AND THE FAST ZONAL MOTION WILL LIMIT THE NORTHERLY
EXTENT OF MOISTURE PLUME. MODERATE-HEAVY RAIN IS LIKELY IN THE
CSRA FOR PERIODS ON SATURDAY AS THE STRONGEST ISENTROPIC LIFT
AND MOISTURE CONVERGENCE RAMPS UP WITH PWAT'S CLIMBING ABOVE
1.25". GENERALLY BETWEEN 0.5-1.0" OF RAIN IS EXPECTED IN THE
CSRA, DECREASING TO THE NORTH AS THE MOISTURE PLUMES REMAINS
LIMITED ACROSS CENTRAL AND ESPECIALLY NORTHERN SC. THERE IS
SOME INCONSISTENCY IN GUIDANCE OVER HOW FAST SOME ADDITIONAL
COASTAL LOW DEVELOPMENT WILL OCCUR AS THE SOUTHERN AND NORTHERN
STREAMS COMPLETELY PHASE AND THE LOW MOVES OFFSHORE. SO PRECIP
CHANCES LINGER A BIT INTO SUNDAY AS WE SIT TO THE WEST-NORTHWEST
OF THE POTENTIALLY STRENGTHENING LOW.
STRONG COLD, DRY ADVECTION WILL THEN DOMINANT THE NEXT FEW DAYS
WITH LATE SUNDAY AND ESPECIALLY MONDAY BEING THE TRANSITION DAYS
AHEAD OF THE ARCTIC AIRMASS. EC EFI AND GEFS CONSENSUS IS
IMPRESSIVE OVER THE EXTENT AND INTENSITY OF THIS COLD OUTBREAK.
EC EFI AND NAEFS PERCENTILES SUGGEST WELL BELOW AVERAGE TEMPS,
WITH DAYTIME HIGHS AND OVERNIGHT LOWS 15-25 DEGREES BELOW
AVERAGE. THERE IS A GOOD LIKELIHOOD THAT WE WILL MEET COLD
WEATHER ADVISORY CRITERIA AT SOME POINT NEXT WEEK WITH THIS
AIRMASS.
WHILE THE COLD OUTBREAK IS HIGH CONFIDENCE, WHAT FOLLOWS IS
LESS CONFIDENT, BUT QUITE INTERESTING. ALL MAJOR PIECES OF
GUIDANCE, INCLUDING THE MAJORITY OF GEFS AND ECE MEMBERS SHOW
SOME SORT OF COASTAL LOW DEVELOPING ALONG THE SOUTHEASTWARD
EXTENT OF THE PRIMARY COLD DOME. CLIMATOLOGICALLY, THIS TYPE OF
SETUP IS FAVORABLE FOR WINTRY PRECIP IN THE CAROLINAS AND
EASTERN GA, BUT IT RAISES A SERIES OF POSSIBLE OUTCOMES AS WELL,
WHICH ARE SHOWN WELL IN GUIDANCE NOW. THE EC AND CANADIAN
(ALONG WITH THEIR ENSEMBLES) SHOW A CLASSIC SOUTHERN SLIDER
OVERRUNNING EVENT; ECE PROBS OF GREATER THAN 1.0" OF SNOW OVER
MUCH OF THE AREA CONTINUES TO EXCEED 40% FOR MULTIPLE RUNS IN A
ROW NOW. DITTO FOR THE CANADIAN. HOWEVER, THESE MEAN PROBS ARE A
BIT BIASED TOWARDS THE HIGH END MEMBERS OF THE ENSEMBLES. THESE
HIGH END MEMBERS RAISE THEIR OWN INTERESTING POINT BY
THEMSELVES HOWEVER. NOW ON THE OTHER END FOR THE POSSIBLE
TUESDAY- THURSDAY SYSTEM, THE GEFS OVER THE LAST FEW RUNS
PRESENTS THE CLASSIC SUPPRESSED SOLUTION WITH THE SURFACE HIGH
DRAGGED TOO FAR SOUTH AND FORCING ANY SYNOPTIC FORCING WELL
SOUTH. SO, AT THIS POINT, BASED ON THE EXTENT OF THE AIRMASS,
TYPICAL TRENDS IN ENSEMBLES IN THE 6-10 DAY WINDOW, AND THE
CURRENT DEPICTIONS, CONFIDENCE IS INCREASING IN SOME WINTRY
PRECIP IN THE CAROLINAS AND EASTERN GA; HOWEVER, AS WITH ALL
POSSIBLE WINTRY PRECIP SYSTEMS AROUND HERE IT WILL TAKE TIME TO
FIGURE THIS OUT.
AVIATION /18Z WEDNESDAY THROUGH MONDAY/
VFR CONDITIONS TONIGHT INTO THURSDAY.
DRY HIGH PRESSURE MOVING INTO THE REGION BEHIND A COLD FRONT
THAT HAS MOVED SOUTH OF THE REGION WILL KEEP VFR CONDITIONS
ACROSS THE TAF SITES THROUGH THE PERIOD. MAY SEE SOME THIN
SCATTERED CIRRUS, BUT THAT WILL BE THE ONLY CLOUDS TO SPEAK OF
TONIGHT. WITH HOW DRY THE AIRMASS IS, FOG IS NOT EXPECTED. WITH
THAT SAID, CAN NOT RULE OUT THE USUAL PATCHY STEAM FOG ALONG
THE RIVER NEAR AGS THROUGH THE NIGHT. WINDS NORTHERLY THIS
AFTERNOON AROUND 5 KNOTS, THEN LIGHT AND VARIABLE TO CALM
OVERNIGHT. ONCE MIXING OCCURS THURSDAY LATE MORNING, WINDS TURN
SOUTHWESTERLY AND BECOME GUSTY AT TIMES.
EXTENDED AVIATION OUTLOOK...THE NEXT CHANCE FOR SIGNIFICANT
RESTRICTIONS WILL BE LATE FRIDAY AND SATURDAY AS MOISTURE
SPREADS INTO THE SOUTHEAST.
CAE WATCHES/WARNINGS/ADVISORIES
SC...NONE.
GA...NONE.
SYNOPSIS...
NEAR TERM...
SHORT TERM...
LONG TERM...
AVIATION...
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