210
FXUS62 KCAE 161030
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
530 AM EST THU JAN 16 2025
SYNOPSIS
DRY AND SEASONABLE TEMPERATURES THROUGH FRIDAY WITH HIGH
PRESSURE OVER THE AREA. WIDESPREAD SHOWERS EXPECTED SATURDAY AS
A LOW PRESSURE SYSTEM MOVES INTO THE EASTERN U.S. 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 PRECIPITATION CHANCES WITH SOME WINTRY
POTENTIAL POSSIBLE.
NEAR TERM /THROUGH TONIGHT/
KEY MESSAGE(S):
- QUIET AND BREEZY THIS AFTERNOON, WITH TEMPERATURES NEAR TO
SLIGHTLY ABOVE NORMAL
CLEAR SKIES HAVE OVERSPREAD THE FORECAST AREA TONIGHT WITH PWS
WAY LESS THAN HALF AN INCH. DEWPOINTS ARE GENERALLY IN THE UPPER
TEENS OR LOW 20S RIGHT NOW, FACILITATING TEMPS FALLING INTO THE
MID AND UPPER 20S. THERE HAVE BEEN SOME LIGHT WINDS, WHICH IS
ALLOWING THESE TEMPS TO BOUNCE UP AND DOWN A BIT BUT IN
GENERAL EXPECT LOW TO MID 20S FOR LOWS BY 7A. QUIET WEATHER IS
EXPECTED THROUGH THE DAY TODAY. SHARP SHORTWAVE IS FORECAST TO
CONTINUE DIGGING THROUGH THE EASTERN CONUS RIGHT NOW, WITH THE
FORECAST AREA FALLING UNDER THE INFLUENCE OF A LARGE LOW
PRESSURE SYSTEM ACROSS SOUTHERN CANADA. THE PRESSURE GRADIENT IS
EXPECTED TO INTENSIFY THROUGH THE DAY AS LARGE SURFACE PRESSURE
FALLS PASS OVER THE AREA AHEAD OF THE APPROACHING SHORTWAVE. SO
LOOK FOR BREEZY, SOUTHWESTERLY FLOW TO DEVELOP THIS AFTERNOON
WITH GUSTS UPWARDS OF 30 MPH OR MORE. THIS IS BORDERLINE LAKE
WIND CRITERIA; HOWEVER, WITH LAKE TEMPERATURES GENERALLY IN THE
MID 40S, THIS DOES NOT FAVOR THE WINDS MIXING TO THE LAKE
SURFACE TOO MUCH DURING THE DAY. HIGHS WILL BE QUITE NICE - IN
THE 55F TO 60F RANGE THIS AFTERNOON. DRY FRONT SHOULD MOVE
THROUGH TONIGHT WITH BARELY EVEN ANY CLOUD COVER. WINDS WON'T
IMMEDIATELY FALL OFF BUT SHOULD SLOWLY DECREASE IN STRENGTH
OVERNIGHT. LOOK FOR LOWS IN THE UPPER 20S AND LOWER 30S ACROSS
THE AREA.
SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/
KEY MESSAGE(S):
- DRY HIGH PRESSURE OVER THE AREA.
- TEMPERATURES SEASONABLE.
FRIDAY...THE UPPER TROUGH CENTERED OVER THE NORTHEASTERN CONUS
MOVES OFF THE COAST AND SHORT WAVE RIDGING EXPECTED OVER THE
CAROLINAS/GEORGIA. THE SURFACE RIDGE MOVES OFF THE COAST IN THE
AFTERNOON AND WARM ADVECTION NOTED. THE AIR MASS REMAINS DRY
WITH PRECIPITABLE WATER REMAINING QUITE LOW THROUGH THE DAY,
AROUND 0.2 INCHES TEMPERATURES EXPECTED TO BE SEASONABLE IN THE
MID TO UPPER 50S ACROSS MUCH OF THE AREA.
FRIDAY NIGHT..A HIGHLY AMPLIFIED UPPER TROUGH OVER THE NORTHERN
PLAINS TO THE GREAT LAKES WILL BEGIN TO AMPLIFY INTO THE
EASTERN CONUS. A SOUTHERN STREAM SHORT WAVE AND SURFACE LOW WILL
BE MOVING TOWARD THE SOUTHEASTERN STATES FROM THE PLAINS.
MOISTURE FROM THE GULF OF MEXICO WILL SURGE NORTH AIDED BY 40-50
KT 850MB JET AHEAD OF THE SHORT WAVE AND PARENT SURFACE LOW.
SHOWERS SHOULD REMAIN MAINLY TO THE WEST OF THE AREA THROUGH
MOST OF THE NIGHT, BUT A FEW SCATTERED SHOWERS ARE POSSIBLE,
MAINLY IN THE CSRA AND SC PIEDMONT BEFORE DAWN. EXPECT
INCREASING CLOUDS THROUGH THE NIGHT AND THE LOW TEMPERATURES ARE
MORE LIKELY TO OCCUR BEFORE MIDNIGHT SO EXPECT RISING TEMPS
TOWARD DAYBREAK.
LONG TERM /SATURDAY THROUGH WEDNESDAY/
KEY MESSAGE(S):
- WIDESPREAD MODERATE RAIN EXPECTED SATURDAY MORNING 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 HIGH FOR AN UNUSUALLY COLD AIR MASS OVER THE AREA
NEXT WEEK.
- CONFIDENCE REMAINS LOW IN ANYTHING SPECIFIC ABOUT THE
POSSIBLE WINTRY PRECIP NEXT WEEK.
PRETTY IMPRESSIVE CYCLOGENESIS AND SYNOPTIC FORCING WILL
DEVELOP ACROSS THE SOUTHEAST US AHEAD OF THE SHORTWAVE AS THE
SOUTHERN AND NORTHERN STREAM JETS PHASE. SC APPEARS TO BE IN
FAVORABLE UPPER JET ENTRANCE (JET-MAX OVER EASTERN NC) AND EXIT
REGIONS (JET-MAX EAST-WEST ACROSS GULF COAST) WITH STRONG UPPER
LEVEL DIVERGENCE NOTED. 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.
THE MOISTURE FLUX AND STRONGEST INSENTROPIC LIFT APPEARS TO BE
FOCUSED IN THE CSRA TO SOUTHEAST SC IN THE MORNING. PRECIPITABLE
WATER 1-1.2 INCHES. 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 HIGH 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 WITH 20-30 % PROBABILITY > 1 INCH SNOW EC
ENSEMBLE AND 40-50 % SNOW IN THE CANADIAN ENSEMBLE. THIS IS
ABOUT THE SAME AS PREVIOUS RUNS. 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 NEXT WEEK WITH MULTIPLE
SCENARIOS. HOWEVER, AS WITH ALL POSSIBLE WINTRY PRECIP SYSTEMS
AROUND HERE IT WILL TAKE TIME TO FIGURE THIS OUT.
AVIATION /12Z THURSDAY THROUGH MONDAY/
VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD, WITH GUSTY WINDS
LIKELY THIS AFTERNOON.
THE FORECAST CONTINUES TO LOOK QUIET THROUGHOUT THE 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. WE MAY SEE WINDS FALL TO CALM BY
THE END OF THIS TAF PERIOD BUT CONFIDENCE ISN'T HIGH ENOUGH IN
THAT SCENARIO TO JUSTIFY ADDING A A NEW LINE FOR IT. SO THE
FORECAST REMAINS LARGELY UNCHANGED FROM THE PREVIOUS ISSUANCE.
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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