443
FXUS62 KCAE 160405
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
1105 PM EST SAT FEB 15 2025
SYNOPSIS
A STRONG COLD FRONT WILL MOVE THROUGH THE REGION SUNDAY MORNING.
WIDESPREAD SHOWERS AND ISOLATED THUNDERSTORMS ARE EXPECTED ALONG
AND AHEAD OF THE FRONT. STRONG GUSTY WINDS ARE EXPECTED THROUGH
THE DAY. THE WINDS WILL SLOWLY SUBSIDE SUNDAY NIGHT AS THE
PRESSURE GRADIENT RELAXES. A COOL AND DRY AIR MASS WILL SETTLE
OVER THE AREA THROUGH TUESDAY. A LOW PRESSURE SYSTEM WILL MOVE
INTO THE SOUTHEASTERN STATES MID-WEEK WITH WINTRY PRECIPITATION
POSSIBLE ACROSS THE NORTHERN MIDLANDS. A COLD AND DRY AIR MASS
WILL BUILD INTO THE AREA LATE WEEK WITH BELOW NORMAL
TEMPERATURES CONTINUING INTO NEXT WEEKEND.
NEAR TERM /UNTIL 7 AM SUNDAY MORNING/
KEY MESSAGE(S):
- SCATTERED SHOWERS CONTINUE THIS EVENING
A STRONG COLD FRONT WILL MOVE ACROSS THE DEEP SOUTH TONIGHT AND
ENTER INTO THE FORECAST AREA FROM THE WEST AROUND DAY BREAK.
TONIGHT, AHEAD OF THE FRONT, ISENTROPIC LIFT WILL LEAD TO
ISOLATED OR SCATTERED SHOWERS. HOWEVER THE DEEPER MOISTURE
SHIFTS NORTH OF THE FA LATE TONIGHT SO SHOWER ACTIVITY SHOULD BE
LOWER THAN EARLIER IN THE DAY. A TIGHT TEMPERATURE GRADIENT
OVER THE AREA WILL SLOWLY ERODE THROUGH THE NIGHT AS THE FRONT
APPROACHES. FOG HAS DEVELOPED ALONG AND NORTH OF THIS BOUNDARY
IN THE SHALLOW COOL AIR AT THE LOW LEVELS. PATCHY DENSE FOG CAN
BE EXPECTED FOR MUCH OF THE FA THROUGH 5 AM BEFORE BOUNDARY
ERODES AND THE WINDS PICK UP. EXPECT A NON-DIURNAL TEMPERATURE
TREND WITH LOWS FOR THE NIGHT LIKELY HAVING ALREADY OCCURRED.
ONGOING CONVECTION IN GA WILL BE VERY NEAR OR HAVE ENTERED THE
CWA FROM THE WEST AT THE END OF THE NEAR TERM. WINDS WILL PICK
UP AROUND SUNRISE BUT THE STRONGEST WINDS ARE EXPECTED PAST 7
AM, COVERED FURTHER IN THE SHORT TERM SECTION.
SHORT TERM /7 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/
KEY MESSAGE(S):
- WINDY CONDITIONS AND SOME STRONG-SEVERE THUNDERSTORMS ARE
LIKELY BETWEEN 8AM AND NOON. BREEZY CONDITIONS WILL LINGER
THROUGH THE AFTERNOON.
BY 6AM SUNDAY, A STRONG FRONT WILL BE APPROACHING THE AREA FROM THE
WEST. A WIDE SWATH OF STRONG SOUTH-SOUTHWESTERLY 850MB WINDS WILL
PROCEED THE FRONT ITSELF, WITH GUIDANCE CONSISTENTLY SHOWING 60+
KNOTS THROUGHOUT SUNDAY MORNING. CONSEQUENTLY, THE GRADIENT SURFACE
WINDS WILL STEADILY STRENGTHEN THROUGHOUT EARLY SUNDAY MORNING AHEAD
OF THE CONVECTIVE LINE ITSELF. WINDS 25-35 MPH ARE LIKELY AHEAD OF
THE LINE, BUT DUE TO THE NEUTRAL STABILITY, THE STRONGEST 850MB
WINDS WILL LIKELY NOT MIX DOWN WITHOUT FORCING. DESPITE EXTREME LOW
LEVEL SHEAR, THE SEVERE-TORNADO THREAT IS RELATIVELY LOW FROM THIS
CONVECTIVE LINE, AS THERE IS LITTLE IF ANY MOST UNSTABLE INSTABILITY
(LET ALONE ANY SURFACE BASED CAPE); HREF MEAN MU CAPE ONLY CLIMBS TO
AROUND 100 J/KG WITH NO MEMBERS SHOWING ANYTHING MORE APPRECIABLE.
HOWEVER, THE SYNOPTIC AND MESOSCALE FORCING WILL BE SIGNIFICANT
ALONG THIS LINE, SO AN ISOLATED TORNADO IS NOT OUT OF THE QUESTION.
SPC CONTINUED THEIR MARGINAL RISK OUTLOOK AS A RESULT. A WIND
ADVISORY IS IN EFFECT STARTING AT 5AM TO COVER THE PREFRONTAL
GRADIENT WINDS AND COLD ADVECTION BEHIND THE LINE; SHORT FUSED
WARNINGS WILL BE USED AS NEEDED FOR SEGMENTS OF THE CONVECTIVE LINE
THAT WARRANT ADDITIONAL ATTENTION. THE STRONGEST WINDS FROM THE
SYSTEM WILL LIKELY OCCUR WITH THE MIXING FROM CONVECTION SHOWERS-
STORMS OR DIRECTLY BEHIND THE LINE. HRRR CROSS SECTIONS SUGGEST SOME
VERY STRONG DESCENT BEHIND THE LINE, ADDING ANOTHER MECHANISM TO MIX
DOWN STRONGER WINDS. THE GENERAL TIMING LOOKS TO BE ROUGHLY 7AM-
NOON FOR THE CONVECTIVE LINE TO PUSH FROM THE CSRA THROUGH THE
COASTAL PLAIN AND EASTERN MIDLANDS.
BEHIND THE FRONT, WINDS WILL SHIFT OUT OF THE WEST AND REMAIN BREEZY
THROUGHOUT THE AFTERNOON. COLD ADVECTION, RELATIVELY DEEP MIXING,
AND UNIDIRECTIONAL SHEAR SHOULD EASILY BE ABLE TO MECHANICALLY MIX
DOWN 25-35 MPH WINDS UNTIL SUNDAY EVENING.
LONG TERM /MONDAY THROUGH SATURDAY/
KEY MESSAGE(S):
-DRY AND COOL EARLY IN THE WEEK.
-POTENTIAL FOR WINTRY WEATHER MIDWEEK.
-COLDER THAN NORMAL INTO NEXT WEEKEND.
MONDAY AND TUESDAY...UPPER TROUGH OVER EASTERN CANADA AND
TROUGH OUT IN THE INTERMOUNTAIN WEST WITH RESULTING FAST ZONAL
FLOW ALOFT ACROSS THE EASTERN CONUS EARLY IN THE WEEK. AT THE
SURFACE, A VERY STRONG PRESSURE RIDGE OVER SOUTH CENTRAL CANADA
WILL BE BUILDING SOUTHEAST AND EXPECT GENERALLY DRY AND COOL
CONDITIONS, SLIGHTLY WARMER TUESDAY AS WARM ADVECTION DEVELOPS
AS THE UPPER TROUGH OUT WEST MOVES INTO THE PLAINS.
COLD AIR DAMMING EXPECTED MID WEEK WITH RIDGE BUILDING IN FROM
THE NORTH INTO THE WESTERN CAROLINAS. WARM FRONT EXPECTED IN
THE SC COASTAL PLAIN. ENSEMBLES SUGGEST WEAK LOW PRESSURE
DEVELOPING ALONG THE GULF COAST, MOVING NORTHEAST TO THE
CAROLINA COAST WEDNESDAY NIGHT. NBM POPS ARE QUITE HIGH DURING
THIS PERIOD SO EXPECT WIDESPREAD RAIN, ALTHOUGH HEAVIER RAIN
FOCUSED IN THE COASTAL PLAIN CLOSER TO MAX MOISTURE FLUX AXIS
SUGGESTED IN THE NAEFS GUIDANCE. CUT MAX TEMPS WEDNESDAY DUE TO
POTENTIAL COLD AIR DAMMING ESPECIALLY NORTH MIDLANDS. SOUNDINGS
SUGGEST A PRECIP TYPE ISSUE WEDNESDAY NIGHT INTO THURSDAY
MORNING WITH WINTRY PRECIP POSSIBLE IN THE NORTHERN MIDLANDS.
FREEZING RAIN THE MAIN THREAT. NOTE THE ECMWF DETERMINISTIC IS
RATHER THREATENING. ENSEMBLES SHOW AN ANOMALOUSLY DEEP UPPER LOW
FROM THE OHIO VALLEY EAST ACROSS THE MID ATLANTIC TRANSITIONING
TO FAST ZONAL FLOW ALOFT ACROSS THE SOUTHEAST. HIGH PRESSURE
WILL BE BUILDING SOUTHEAST FROM THE PLAINS AND THIS SHOULD LEAD
TO TEMPERATURES BELOW NORMAL AND COOLER NORMAL TEMPERATURES INTO
NEXT WEEKEND.
AVIATION /04Z SUNDAY THROUGH THURSDAY/
...LOW CLOUDS AND FOG CONTINUE TONIGHT....
ALL TERMINALS ARE CURRENTLY SEEING LIFR CIGS IN ADDITION TO
REDUCED VISIBILITIES. AREAS OF PATCHY DENSE FOG ARE POSSIBLE
TONIGHT UNTIL A WARM FRONT LIFTS NORTH AHEAD OF AN APPROACHING
COLD FRONT. EXPECT SOME IMPROVEMENT TO CEILINGS AND VISIBILITY
FOLLOWING THE PASSAGE OF THE FRONT. STRONG WINDS NEAR THE TOP
OF THE BOUNDARY LAYER ARE EXPECTED TO CONTINUE INTO SUNDAY
MORNING SO MAINTAINED LLWS AT ALL TAF SITES. A STRONG COLD FRONT
WILL SWEEP ACROSS THE FORECAST AREA SUNDAY MORNING BRINGING A
PERIOD OF RAIN AND ISOLATED THUNDERSTORMS. WINDS COULD BE
PARTICULARLY STRONG WITHIN THE CONVECTION, BUT ARE ALSO
ANTICIPATED TO BE BREEZY BOTH BEFORE AND AFTER THE FRONTAL
PASSAGE, AS SOUTHWESTERLY WINDS TURN WESTERLY. SKIES CLEAR OUT
AND WINDS DIMINISH SUNDAY EVENING.
EXTENDED AVIATION OUTLOOK...A APPROACHING SYSTEM ON WEDNESDAY
AND THURSDAY WILL BRING SOME PRECIPITATION AND ASSOCIATED
RESTRICTIONS.
HYDROLOGY
RECENT RAINFALL TOTALS IN THE HEADWATERS OF THE AREA RIVERS IN
THE UPSTATE OF SC AND WESTERN NC INDICATE THAT 3 TO 5 INCHES
FELL WITH AMOUNTS FROM ONE HALF INCH EASTERN MIDLANDS TO 2
INCHES ACROSS THE PIEDMONT. THIS HAS PRODUCED RISES ON THE AREA
RIVERS AND STREAMS THAT WILL CONTINUE OVER THE WEEKEND. THE
RIVERS ARE NEAR CREST AND FORECAST TO FALL OVER THE NEXT COUPLE
OF DAYS. HOWEVER, ADDITIONAL SYSTEMS ARE EXPECTED TO BRING MORE
RAINFALL TO THE REGION THROUGH THE PERIOD.
CAE WATCHES/WARNINGS/ADVISORIES
SC...DENSE FOG ADVISORY UNTIL 5 AM EST SUNDAY FOR SCZ016-018-
020>022-025>031-037-115-116-135-136.
WIND ADVISORY FROM 5 AM TO 6 PM EST SUNDAY FOR SCZ016-018-
020>022-025>031-035-037-038-041-115-116-135>137.
GA...DENSE FOG ADVISORY UNTIL 5 AM EST SUNDAY FOR GAZ040-063>065.
WIND ADVISORY FROM 5 AM TO 6 PM EST SUNDAY FOR GAZ040-063>065-
077.
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