551
FXUS62 KCAE 160548
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
1248 AM EST THU JAN 16 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 /UNTIL 6 AM THIS MORNING/
KEY MESSAGE(S):
- DRY HIGH PRESSURE CONTINUES TO BUILD INTO THE REGION WITH CHILLY
TEMPERATURES EXPECTED OVERNIGHT.
A POSITIVELY TITLED SHORTWAVE TROUGH IS EVIDENT IN WATER VAPOR
IMAGERY EXTENDING ACROSS THE OHIO VALLEY AND INTO NE TEXAS. THIS
BRINGS MAINLY ZONAL FLOW ALOFT ACROSS THE REGION WITH SOME
SOUTHWESTERLY FLOW NOTED TOWARD THE GULF OF MEXICO, ALLOWING SOME
LIMITED HIGH LEVEL MOISTURE TO FUNNEL ABOVE A STALLED SURFACE
FRONTAL BOUNDARY THAT IS DRAPED ACROSS CENTRAL GA, AL, AND MS. THIS
IS ALLOWING SOME HIGH LEVEL CLOUDS TO PASS THROUGH THE CWA BUT AS
THIS BOUNDARY SLOWLY STARTS TO SINK SOUTH OVERNIGHT AND THE TROUGH
SLIDES TOWARD THE EAST, EXPECT MOSTLY CLEAR SKIES INTO THE OVERNIGHT
AS A NIGHT OF STRONG RADIATIONAL COOLING SETS UP.
WINDS HAVE ALREADY GONE CALM ACROSS MUCH OF THE CWA AND THESE HIGH
LEVEL CLOUDS ARE EXPECTED TO HAVE LIMITED INFLUENCE ON TEMPERATURES
AS THEY ARE FAIRLY THIN. DUE TO THIS, HAVE TRENDED TOWARD THE NBM
25TH PERCENTILE FOR TEMPERATURES TONIGHT. EXPECT OVERNIGHT LOWS TO
DROP INTO THE UPPER 20S TO NEAR 30 IN THE SOUTHERN MIDLANDS AND
CSRA, MID TO HIGH 20S IN THE CENTRAL MIDLANDS, AND THE LOW 20S IN
NORTHERN SECTIONS OF THE CWA WITH DRIER AIR IN PLACE HERE.
TEMPERATURES AND SOUTHWESTERLY WINDS THEN ARE EXPECTED TO QUICKLY
REBOUND AFTER DAYBREAK.
SHORT TERM /6 AM THIS MORNING 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 /06Z THURSDAY THROUGH MONDAY/
VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD, WITH GUSTY WINDS
LIKELY THIS AFTERNOON.
HIGH CLOUDS ARE QUICKLY PUSHING SOUTHEASTWARD AWAY FROM THE TAF
SITES, LEAVING CLEAR SKIES IN THEIR WAKE. THAT WILL BE A COMMON
THEME THROUGHOUT THIS PERIOD, WITH CLEAR SKIES EXPECTED
THROUGHOUT THE FORECAST PERIOD. VERY DRY AIR IS IN PLACE AND
JUST DOES NOT FAVOR THE DEVELOPMENT OF CLOUDS, EVEN WITH A DRY
FRONT APPROACHING LATER IN THE PERIOD. WINDS ARE EXPECTED TO
PICK UP OUT OF THE SOUTHWEST THIS AFTERNOON, BECOMING QUITE
GUSTY AS A TIGHT PRESSURE GRADIENT DEVELOPS ACROSS THE FORECAST
AREA. LOOK FOR WINDS TO GUST UPWARDS OF 30 KNOTS AT TIMES
BETWEEN 15Z AND 22Z, WITH WINDS BECOMING LIGHTER THEREAFTER.
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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