971
FXUS62 KCAE 301850
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
250 PM EDT MON JUN 30 2025
SYNOPSIS
TYPICAL SUMMERTIME WEATHER IS EXPECTED TO CONTINUE INTO THE
START OF THE WORK WEEK, WITH NEAR TO SLIGHTLY ABOVE NORMAL
TEMPERATURES AND DAILY SHOWER AND THUNDERSTORM CHANCES.
SHOWERS AND THUNDERSTORM CHANCES RAMP UP FOR TUESDAY AND
WEDNESDAY AS A WEAK FRONT ENTERS THE SOUTHEAST. MORE ISOLATED TO
SCATTERED CONVECTION EXPECTED FOR THE SECOND HALF OF THE WEEK.
NEAR TERM /UNTIL 6 AM TUESDAY MORNING/
KEY MESSAGE(S):
- SEASONAL PATTERN EXPECTED TO CONTINUE, WITH WARM TEMPS AND
SCATTERED SHOWERS/STORMS EXPECTED.
THE PATTERN REMAINS LARGELY UNCHANGED COMPARED TO YESTERDAY, SO A
PERSISTENCE FORECAST IS IN ORDER ACROSS THE AREA. RIDGING REMAINS IN
PLACE ACROSS THE SOUTHEASTERN US, THOUGH IT IS FAIRLY WEAK COMPARED
TO WHAT WE WERE DEALING WITH LAST WEEK. THIS IS PROBABLY AMPLIFYING
SLIGHTLY AS A LATE SEASON TROUGH DIGS THROUGH THE OH AND TN VALLEY
REGION TOWARDS US TODAY. PWS ARE IN THE 1.7"-1.9" ACROSS THE AREA,
WITH MLCAPE OF GENERALLY 1000-1500 J/KG. TEI AND DCAPE ARE NEAR THE
THRESHOLDS OF WHAT YOU'D EXPECT FOR SUB-SEVERE CONVECTION TO BE THE
PRIMARY THREAT FOR THE MOST ROBUST CONVECTION THIS AFTERNOON.
EXPECTING COVERAGE TO GENERALLY BE SIMILAR TO WHAT IT WAS YESTERDAY
WITH SCATTERED SHOWERS AND STORMS DOTTING THE SKIES AND MOVING VERY
SLOWLY. THIS IS LARGELY DRIVEN BY THE AFORMENTIONED RIDGING ACROSS
THE AREA, WITH RAP, REFS, AND HRRR FORECAST SOUNDINGS ALL SHOWING
EVIDENCE OF WEAK SUBSIDENCE ALOFT NEAR THE 500 HPA LAYER. SO WHILE
CONVECTION IS FAVORED, ESPECIALLY IF THE SEA BREEZE WORKS ITS WAY UP
HERE OR ALONG OUTFLOW BOUNDARIES, OVERALL COVERAGE SHOULD STILL
REMAIN ISOLATED TO SCATTERED. HIGHS TODAY ARE EXPECTED TO BE
SEASONAL IN THE LOW 90S. CONVECTION IS EXPECTED TO WANE QUICKLY
BEYOND SUNSET AS INSTABILITY DIES OFF. SO LOOK FOR A PRETTY QUIET
AND WARM NIGHT WITH LOWS IN THE LOW 70S ACROSS THE AREA.
SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/
KEY MESSAGE(S):
- RAIN CHANCES INCREASE MID-WEEK AS A WEAK FRONT APPROACHES
- RAIN MAY BE HEAVY AT TIMES WITH A MARGINAL THREAT OF FLASH FLOODING
AN UPPER LEVEL TROUGH SHIFT EAST MID-WEEK ALLOWING FOR STRENGTHENING
SOUTHWEST FLOW. THIS WILL LEAD TO STRENGTHENING MOISTURE
ADVECTION INTO THE SOUTHEAST. MEAN PWAT VALUES FROM MODEL
ENSEMBLES INCREASE TO OVER 2 INCHES. THE STRONGEST FORCING FOR
CONVECTION WILL LIKELY REMAIN WEST OF THE AREA THROUGH THE DAY
ON TUESDAY. HOWEVER DIURNALLY DRIVEN SHOWERS AND STORMS SHOULD
DEVELOP IN THE WARM, MOIST AIRMASS.
AS A WEAK COLD FRONT CONTINUES TOWARDS THE SOUTHEAST SHOWERS AND
STORMS BECOME INCREASINGLY LIKELY FOR WEDNESDAY. ATMOSPHERIC
MOISTURE CONTINUES TO INCREASE WITH THE NAEFS MEAN PWAT VALUES
EXCEEDING THE 90TH PERCENTILE ACROSS THE AREA. THERE WILL BE A
LOCALIZED THREAT OF EXCESSIVE RAINFALL MAINLY DUE TO THE ANOMALOUSLY
HIGH PWATS AND LONG, SKINNY CAPE PROFILES TYPICAL OF A FLOODING
THREAT. HOWEVER, STORMS SHOULD BE MOVING FAST ENOUGH TO LIMIT ANY
SIGNIFICANT OR WIDESPREAD FLOODING PROBLEMS. SYNOPTIC FORCING AND
ENHANCED CONVERGENCE AT THE LOW LEVELS WILL ALLOW CONVECTION TO
CONTINUE INTO THE EVENING AND OVERNIGHT PERIODS.
WITH INCREASED MOISTURE AND A BREAKDOWN OF THE RIDGE, EXPECT HIGHS A
FEW DEGREES COOLER THAN THE PREVIOUS FEW DAYS FOR TUESDAY, IN THE
UPPER 80S TO LOW 90S. COOLER ONCE AGAIN WEDNESDAY WITH HIGHS
GENERALLY IN THE MID TO UPPER 80S. LOWS FOR BOTH TUESDAY AND
WEDNESDAY IN THE LOW 70S.
LONG TERM /THURSDAY THROUGH MONDAY/
KEY MESSAGE(S):
- NEAR NORMAL TEMPS WITH ISOLATED DIURNAL CONVECTION EACH DAY
GLOBAL ENSEMBLES FAVOR BROAD TROUGHING OVER THE EASTERN US THROUGH
THE LONG TERM. WEAK SOUTHERLY FLOW, A DECAYING FRONTAL BOUNDARY AND
PWAT VALUES NEAR OR ABOVE NORMAL WILL SUPPORT AT LEAST A CHANCE OF
RAIN EACH DAY. THE HIGHEST VALUES WILL BE NEARER THE COAST WHERE
MOISTURE IS DEEPER. TEMPERATURES WILL GENERALLY BE NEAR NORMAL WITH
HIGHS IN THE LOW TO MID 90S DEPENDING ON CONVECTIVE COVERAGE.
NIGHTTIME LOWS WILL BE IN THE LOW TO MID 70S.
AVIATION /19Z MONDAY THROUGH SATURDAY/
GENERALLY VFR CONDITIONS EXPECTED THROUGH THE FORECAST PERIOD
OUTSIDE OF CONVECTION.
PATTERN LOOKS QUITE SIMILAR TO WHAT WE HAVE SEEN THE LAST COUPLE
OF DAYS. RIDGING ALOFT IS OVER THE AREA, HELPING TO SUPPRESS
WIDESPREAD CONVECTION BUT GENERALLY ALLOWING SCATTERED
SHOWERS/STORMS TO DEVELOP. EXPECTING THESE TO REMAIN BENIGN BUT
THE STRONGEST THUNDERSTORMS MAY PRODUCE WIND GUSTS OF 25-35
KNOTS IF ONE GOES UP DIRECTLY OVER AN AIRFIELD (SEE THE STORM
THAT IMPACTED CAE YESTERDAY EVENING). PWS ARE HIGH, SO BRIEF
VISIBILITY RESTRICTIONS ARE LIKELY IN ANY HEAVY THUNDERSTORM
THAT DOES MOVE OVER AN AIRFIELD. OVERALL THOUGH, VFR CONDITIONS
ARE EXPECTED TO PREVAIL. AFTER THE SUN SETS, THE CONVECTION WILL
LIKELY DIMINISH IN COVERAGE AND INTENSITY, WITH SCATTERED CLOUD
DEBRIS REMAINING ACROSS THE AREA INTO THE NIGHT. AGS/OGB MAY SEE
PATCH GROUND FOG TONIGHT BUT IT SEEMS PRETTY UNLIKELY TO BE A
PROBLEM GIVEN THAT GUIDANCE IS DEVELOPING A 20-25 KNOT LOW-
LEVEL JET TONIGHT. BY MID-MORNING TOMORROW, THERE IS SOME
INDICATION THAT LARGE SCALE FORCING + INCREASED LOW-LEVEL
MOISTURE AHEAD OF OUR NEXT FRONT MAY AID IN THE DEVELOPMENT OF
MVFR CIGS AS CUMULUS GETS GOING. THERE IS ONLY A 40ISH PERCENT
PROBABILITY OF MVFR CIGS MID-MORNING TOMORROW IN HREF GUIDANCE,
SO LEFT BKN035 BY 15Z TO TREND IN THAT DIRECTION. MORE
WIDESPREAD SHOWERS AND STORMS ARE EXPECTED TOWARDS THE END OF
THIS PERIOD TOMORROW, SO MENTIONED VCSH FOR NOW WITH THE
EXPECTATION THAT THUNDERSTORMS WILL BE ADDED AS WE GET CLOSER TO
THE TIMEFRAME.
EXTENDED AVIATION OUTLOOK...PATCHY GROUND FOG POSSIBLE EACH
NIGHT...BUT IS UNLIKELY TO CAUSE SIGNIFICANT ISSUES AT THE
TERMINALS. A FRONT WILL APPROACH THE SOUTHEAST TUE/WED LEADING
TO INCREASED THUNDERSTORM CHANCES.
CAE WATCHES/WARNINGS/ADVISORIES
SC...NONE.
GA...NONE.
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