158
FXUS62 KCAE 291803
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
203 PM EDT SAT MAR 29 2025
SYNOPSIS
MOISTURE IS INCREASING TODAY, WITH RAIN CHANCES INCREASING INTO
SUNDAY MORNING AND SHOWERS AND THUNDERSTORMS POSSIBLE SUNDAY
AFTERNOON. HIGHER CHANCES FOR SHOWERS AND THUNDERSTORMS ARRIVE
ON MONDAY AS A COLD FRONT APPROACHES FROM THE WEST. NEAR TO
ABOVE NORMAL TEMPERATURES EXPECTED TO CONTINUE THROUGH THE NEXT
SEVEN DAYS.
NEAR TERM /THROUGH TONIGHT/
KEY MESSAGE(S):
- INCREASING MOISTURE AND CLOUD COVER BUT STAYING WARM.
- LESSENED FIRE DANGER WITH INCREASING HUMIDITIES.
- RAIN CHANCES MOVE IN LATE AND INTO SUNDAY.
MOISTURE CONTINUES TO INCREASE ACROSS THE REGION THIS AFTERNOON
AS THE WEAKENING UPPER TROUGH OVER THE LOWER MS VALLEY
CONTINUES TO NEAR THE FA WITH PWAT'S SITTING AT 0.90" AS
SOUTHERLY TO SOUTHEASTERLY FLOW ALSO AIDS IN SOME WARM ADVECTION
AND THE DEVELOPMENT OF A CUMULUS DECK ACROSS THE FA. THERE IS
ALSO INCREASING HIGH CLOUDS AS WELL WITH THE APPROACHING TROUGH
BUT WARM ADVECTION IS ALLOWING TEMPERATURES TO BE ON TRACK TO
REACH THE UPPER 70S TO NEAR 80 AGAIN THIS AFTERNOON. THE UPPER
TROUGH WILL MOVE INTO THE REGION TONIGHT AND INTO SUNDAY MORNING
WHERE DEEPER/STRONGER ISENTROPIC LIFT SETS UP, ESPECIALLY AFTER
4-6 AM SUNDAY, ALONG WITH AT LEAST SOME WEAK VORTICITY
ADVECTION WITH THE UPPER TROUGH AS PWAT'S RAISE TO BETWEEN
1.30-1.45" AND SOUTHERLY FLOW AT 925 MB INCREASES TO 25-30 KTS.
THIS WILL LEAD TO SOME ISOLATED RAIN SHOWER CHANCES STARTING
DURING THIS TIME FRAME BUT ANY POTENTIAL THUNDERSTORMS LOOK TO
HOLD OFF UNTIL LATER SUNDAY. WITH THE EXPECTED CLOUD COVER
CONTINUING AND INCREASING MOISTURE TONIGHT, LOWS WILL BE LIMITED
TO THE UPPER 50S TO NEAR 60.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/
KEY MESSAGE(S):
- SHOWERS AND THUNDERSTORMS POSSIBLE SUNDAY AND SUNDAY
AFTERNOON.
- STRONG TO SEVERE THUNDERSTORMS POSSIBLE ON MONDAY
AN ACTIVE SHORT TERM PERIOD IS EXPECTED, WITH MUCH NEEDED
RAINFALL FORECAST ACROSS THE AREA BOTH SUNDAY AFTERNOON AND
AGAIN ON MONDAY. COMPLEX SYNOPTIC PATTERN OVER THE CONUS IS
FORECAST TO UNFOLD DURING THE PERIOD. A DEAMPLIFYING SOUTHERN
STREAM SHORTWAVE IS FORECAST TO APPROACH THE AREA LATE TONIGHT
AND INTO SUNDAY. THIS WILL CONTINUE TO DEAMPLIFY AND LIFT
NORTHWARD AS A STRONGER SHORTWAVE EJECTS EASTWARD FROM THE
ROCKIES ON SUNDAY. MOISTURE RETURN IS FORECAST TO BE ROBUST
THROUGH THE DAY ON SUNDAY, WITH WIDESPREAD DEWPOINTS IN THE 60S
AND PWS RISING WELL ABOVE THE 90TH PERCENTILE BY SUNDAY
AFTERNOON. GUIDANCE HAS BEEN CONSISTENT (OUTSIDE OF THE NAM
SOLUTION) IN SHOWING WIDESPREAD SHOWERS AND THUNDERSTORMS
DEVELOPING SUNDAY AFTERNOON AND EVENING EVEN IN THE WAKE OF THE
WEAKENING TROUGH AXIS. THIS SETUP IS SLIGHTLY ODD; HOWEVER, WITH
STRONG MOISTURE ADVECTION ON THE WESTERN SIDE OF A LOW-LEVEL
RIDGE OF HIGH PRESSURE & PLENTIFUL MOISTURE, STILL THINK THAT
PRECIPITATION IS LIKELY. THERE WILL PROBABLY BE A BIT OF A
GRADIENT IN RAIN CHANCES FROM WEST TO EAST, WITH THE BEST
CHANCES OF SHOWERS/STORMS GENERALLY WEST OF I-77. ANY RAIN
SHOULD DIMINISH ON MONDAY NIGHT AS SUBSIDENCE INCREASES WITH
INCREASING SHORTWAVE RIDGING.
MONDAY LOOKS TO BE A POTENTIALLY ACTIVE DAY. SHORTWAVE TROUGH
OVER THE PLAINS IS EXPECTED TO CONTINUE TO PUSH EASTWARD, WITH
GUIDANCE HONING IN ON A MORE FOCUSED SHORTWAVE DEVELOPING IN THE
TENNESSEE VALLEY AND SHIFTING TOWARDS US ON MONDAY AFTERNOON. A
BROAD RESERVOIR OF INSTABILITY AND ROBUST LOW-LEVEL MOISTURE IS
FORECAST TO EXIST TO OUR SOUTHWEST DURING THIS PERIOD AND LIKELY
WILL BE ADVECTED INTO THE CAROLINAS THROUGH THE DAY ON MONDAY.
FORECAST MODELS CONSISTENTLY HAVE BEEN CHARACTERIZING THIS
AIRMASS TO FEATURE 750-1250 J/KG OF CAPE WITH INCREASING SHEAR
ON THE ORDER OF 35-45 KNOTS BY MONDAY AFTERNOON. THERE IS SOME
EXPECTATION THAT A REMNANT AREA OF CONVECTION SHOULD BE CENTERED
SOMEWHERE TO OUR WEST AND IN THE TENNESSEE RIVER VALLEY BY
MONDAY MORNING. OUR SEVERE THREAT IS GOING TO BE LARGELY
MODULATED BY THIS FEATURE, AS IT COULD BE COME A ROBUST MCS AND
DIVE INTO THE GREATER INSTABILITY ALONG THE GULF COAST AND
PREVENT ANY ROBUST MOISTURE ADVECTION ON MONDAY. HOWEVER, IF
THIS FEATURE IS SOMEWHAT ATTACHED TO THE COLD FRONT TO OUR WEST
BY MONDAY MORNING, A PRETTY ROBUST SEVERE THREAT COULD
MATERIALIZE BY MONDAY AFTERNOON. STRONG, DAMAGING WINDS LOOK TO
BE THE PRIMARY THREAT BUT EMBEDDED TORNADOES (ESPECIALLY WITHIN
A POTENTIAL QLCS) CANNOT BE RULED OUT BY MONDAY AFTERNOON. THE
INSTABILITY/SHEAR COMBO IS ONE WE HAVEN'T REALLY SEEN YET THIS
YEAR, SO WE WILL NEED TO WATCH CONVECTIVE TRENDS AND FORECASTS
CLOSELY OVER THE NEXT 36-48 HOURS. SPC MAINTAINS A SLIGHT RISK
OVER THE AREA TO ACCOUNT FOR THE THREAT. HIGHS ON MONDAY WILL
LIKELY BE IN THE UPPER 70S OR LOWER 80S. THE RAIN THREAT SHOULD
QUICKLY SHIFT EASTWARD ON MONDAY NIGHT AS DRIER AND COOLER AIR
FILTERS IN BEHIND THE COLD FRONT.
LONG TERM /TUESDAY THROUGH FRIDAY/
KEY MESSAGE(S):
- WELL ABOVE NORMAL TEMPERATURES ARE LIKELY BY THE END OF THE
PERIOD
GUIDANCE, IN GENERAL, IS A BIT MORE ON THE SAME PAGE AS WE
MOVE BEYOND THE MONDAY SYSTEM. THE EVOLUTION OF THE PATTERN
STILL REMAINS COMPLEX AND COMPLICATED AS THE SYSTEM MODULATING
IT ALL WILL REMAIN OVER THE NORTHEASTERN PACIFIC/GULF OF ALASKA
THROUGH MUCH OF THE PERIOD. THE GFS/GEFS SOLUTION HAVE TRENDED
TOWARDS THE EC/ECE SOLUTION (WHICH REMAINS LARGELY UNCHANGED
FROM LAST NIGHT). BASICALLY, TRANSIENT SURFACE HIGH PRESSURE AND
TROUGHING IS EXPECTED TO PASS THROUGH THE AREA ON TUESDAY. THIS
SHOULD QUICKLY SHIFT EASTWARD BY WEDNESDAY, WITH SOUTHERLY AND
SOUTHEASTERLY FLOW AGAIN COMMENCING AS HEIGHTS BEGIN TO RISE
ACROSS THE AREA. THIS MAY BE OUR PRIMARY CHANCE FOR RAIN DURING
THE UPCOMING WEEK, AS GUIDANCE DOES SHOW SOME ROBUST MOISTURE
CONVERGENCE ACROSS THE AREA ON WEDNESDAY NIGHT. I'M SOMEWHAT
SKEPTICAL OF OVERALL RAIN CHANCES GIVEN THE RISING HEIGHTS BUT
KEPT SOME POPS IN THERE TO ACCOUNT FOR THE THREAT CURRENTLY.
AS ALL OF THIS OCCURS, MULTIPLE SHORTWAVES ARE EXPECTED TO
ESTABLISH A DEEP TROUGH ACROSS THE DESERT SOUTHWEST BY THE
MIDDLE OF THE WEEK. MULTIPLE SHORTWAVES ARE FORECAST TO PASS
NORTHEASTWARD IN THE FLOW, WITH STRONG UPSTREAM BLOCKING OVER
THE NORTH ATLANTIC HELPING RESULT IN A STRONG, ANOMALOUSLY
STRONG MID-LEVEL RIDGE ACROSS THE SOUTHEASTERN CONUS. AS A
RESULT, CONFIDENCE IS BEGINNING TO INCREASE IN A PERIOD OF NEAR
RECORD HIGHS IN THE THUR-SAT PERIOD OF THIS LONG TERM FORECAST.
THE COMBINATION OF GUIDANCE SHOWING VERY HIGH HEIGHTS, STRONG
SUBSIDENCE BENEATH THE RIDGE KEEPING AFTERNOON SHOWER/STORM
CHANCES AT BAY, AND ANTECEDENT DRYNESS IS LEADING TO ABOVE
NORMAL FORECASTER CONFIDENCE IN VERY WARM TEMPS. THE RECORD
HIGHS AT CAE DURING THIS PERIOD ARE PRETTY ATTAINABLE (LOW 90S
EACH DAY) AND MAY END UP BEING EXPLICITLY FORECAST, ESPECIALLY
SINCE THE DETERMINISTIC NBM SOLUTION TENDS TO STRUGGLE WITH OUR
FIRST WARM SPELL OF THE YEAR. OTHERWISE, SENSIBLE WEATHER LOOKS
FAIRLY QUIET AS THE STRONG RIDGE WILL TEND TO SUPPRESS ANYTHING
OUTSIDE OF WARM TEMPS.
AVIATION /18Z SATURDAY THROUGH THURSDAY/
VFR CONDITIONS CONTINUE TO PERSIST BEFORE EXPECTED STRATUS
DEVELOPMENT INTO SUNDAY MORNING, BRINGING POSSIBLE MVFR TO IFR
RESTRICTIONS ALONG WITH INCREASING RAIN SHOWER CHANCES INTO
SUNDAY AFTERNOON.
THE UPPER DISTURBANCE OVER THE MS VALLEY WILL LIFT ACROSS THE
REGION TONIGHT BUT BEFORE THIS, 5-12 KT SOUTHERLY TO
SOUTHEASTERLY WINDS HAVE CONTINUED TO INCREASE MOISTURE AS A
SCATTERED TO BROKEN CUMULUS DECK BETWEEN 4,000 TO 5,500 FT HAS
DEVELOPED ACROSS ALL SITES WITH CONTINUED PASSING HIGH CLOUDS.
THIS CONTINUES INTO THE EVENING BEFORE THE CUMULUS DECK BEGINS
TO DISSIPATE BUT MID TO HIGH LEVEL CLOUDS CONTINUE TO STREAM IN
AHEAD OF THE UPPER DISTURBANCE. WINDS BECOME LIGHT AND VARIABLE
OVERNIGHT WHERE 25-30 KTS OF FLOW AROUND 2,000 FT IS POSSIBLE
BUT HAVE LEFT LLWS OUT OF THE TAF AT THIS TIME AS THE
EXPECTATION IS FOR MOST LOCATIONS TO KEEP SOME LIGHT WINDS
OVERNIGHT. MODELED SOUNDINGS CONTINUE TO SHOW A SIGNAL FOR
POTENTIAL STRATUS DEVELOPMENT AFTER 9-11Z SUNDAY, LEADING TO
MVFR AND POSSIBLE IFR RESTRICTIONS WHERE PROBABILITIES FOR THIS
ARE BETWEEN 40-60 PERCENT. THIS DECK SLOWLY LIFTS TOWARD THE
END OF THE PERIOD BEFORE RAIN SHOWER CHANCES INCREASE AS WELL,
BUT HAVE LEFT OUT MENTION OF THUNDERSTORMS IN THE TAF AT THIS
TIME AS ANY POTENTIAL FOR THIS SEEMS TO COME JUST AFTER THE
CURRENT PERIOD.
EXTENDED AVIATION OUTLOOK...MORE RESTRICTIONS WILL BE POSSIBLE
MONDAY AS MORE RAIN CHANCES ACCOMPANY A PASSING COLD FRONT.
FIRE WEATHER
THE SOUTH CAROLINA FORESTRY COMMISSION HAS ISSUED A STATEWIDE
BURN BAN UNTIL FURTHER NOTICE.
MOISTURE CONTINUES TO INCREASE TODAY WITH MINIMUM RH VALUES
EXPECTED TO BE NEAR 35-40 PERCENT DURING THE AFTERNOON WITH
SOUTH TO SOUTHEAST WINDS OF 5-10 MPH WITH SOME ISOLATED GUSTS
TOWARD 15-20 MPH POSSIBLE. AS OUR NEXT SYSTEM APPROACHES,
MOISTURE AND RAIN CHANCES CONTINUE TO INCREASE INTO SUNDAY AND
MONDAY.
CAE WATCHES/WARNINGS/ADVISORIES
SC...NONE.
GA...NONE.
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