303
FXUS62 KRAH 121925
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
325 PM EDT MON MAY 12 2025
SYNOPSIS
A SLOW MOVING UPPER LOW CENTERED OVER THE LOWER MISSISSIPPI
RIVER VALLEY WILL DRIFT NORTHEAST THROUGH THE MID SOUTH TO THE
CENTRAL APPALACHIANS THROUGH WEDNESDAY, BRINGING WET AND UNSETTLED
WEATHER TO THE REGION.
NEAR TERM /THROUGH TONIGHT/
AS OF 236 PM MONDAY...
LATEST OBSERVED RAINFALL TOTALS SHOW A FEW STREAKS OF 1 TO 2 INCHES
OVER PORTIONS OF THE SOUTHERN PIEDMONT, WESTERN SANDHILLS, AND
SOUTHERN COASTAL PLAIN. THUS FAR, ANY STRONGER CONVECTION THAT HAS
DEVELOPED TO OUR SOUTH HAS GENERALLY FIZZLED OUT WITH NORTHWARD
EXTENT AFTER ENCOUNTERING MORE STABLE AIR. LOOKING AT SATELLITE
IMAGERY THIS AFTERNOON, HOWEVER, THERE HAVE BEEN NOTICEABLE BREAKS
ACROSS THE SOUTHERN PORTIONS OF CENTRAL NC. AS SUCH, WE ARE STARTING
TO SEE A BIT DEEPER CONVECTION BUBBLE UP ALONG OUR NC/SC BORDER. AS
WE CONTINUE INTO THE LATER AFTERNOON AND EVENING HOURS, EXPECT THIS
DEEPER CONVECTION TO PRODUCE A BIT BETTER RAIN RATES. THE 12Z HREF
LPMM FIELD HIGHLIGHTS THE POTENTIAL FOR HIGHER QPF OVER THE
SANDHILLS/SOUTHERN COASTAL PLAIN AND THE WESTERN TO NORTHERN
PIEDMONT. ANY URBAN AREAS IN THESE LOCATIONS COULD BE SUSCEPTIBLE TO
ISOLATED FLASH FLOODING POTENTIAL THROUGH THE REST OF THIS EVENING.
OTHERWISE, THE BULK OF MODERATE TO HEAVY RAIN SHOULD LARGELY LIFT
NORTH INTO VA LATE TONIGHT THROUGH SUNRISE TUESDAY MORNING. HOWEVER,
SCATTERED SHOWER CHANCES WILL REMAIN POSSIBLE EVERYWHERE GIVEN THE
PROXIMITY TO THE CLOSED LOW AND THE RESIDUAL HIGHLY ANOMALOUS PWAT
(150 TO 175 % OF NORMAL).
WE CONTINUE TO SEE WEAK, BRIEF ROTATION IN SOME OF THE DEEPER
CONVECTIVE CELLS. AS WAS MENTIONED THIS MORNING, GIVEN THERE IS SOME
MARGINAL EFFECTIVE SRH OF ~100 M2S2 FORECAST, COUPLED WITH LOW LCLS,
CAN'T RULE OUT AN ISOLATED BRIEF SPIN-UP TORNADO THROUGH ESPECIALLY
THIS AFTERNOON EVENING.
OTHERWISE, WARM OVERNIGHT LOWS IN THE LOWER 60S ARE EXPECTED.
SHORT TERM /TUESDAY AND TUESDAY NIGHT/
AS OF 325 PM MONDAY...
BY TUESDAY MORNING, THE UPPER LOW WILL BE OVER EASTERN TENNESSEE,
AND THIS WILL DRIFT INTO SOUTHERN OHIO OVER THE NEXT 24 HOURS. THE
SURFACE PATTERN WILL BE COMPLEX, BUT AN AREA OF MODERATE TO HEAVY
RAIN SHOULD BE APPROACHING THE EASTERN COUNTIES AROUND SUNRISE.
MEANWHILE, THERE COULD BE A RELATIVE LULL IN SHOWERS ACROSS WESTERN
COUNTIES DURING THE MORNING. A SHORTWAVE IS EXPECTED TO ROTATE
ACROSS NORTH CAROLINA TUESDAY AFTERNOON, AND THIS WILL LIKELY
TRIGGER ANOTHER ROUND OF WIDESPREAD SHOWERS AND THUNDERSTORMS. ONCE
THE SHORTWAVE MOVES NORTH OVER VIRGINIA TUESDAY EVENING, THE CHANCE
OF SHOWERS SHOULD COME DOWN THROUGH THE NIGHTTIME HOURS.
WHILE SKIES ARE GOING TO REMAIN MOSTLY CLOUDY THROUGH THE DAY,
MODELS ARE IN A BIT OF DISAGREEMENT AS TO THE POTENTIAL FOR STRONG
TO SEVERE STORMS DURING THE AFTERNOON. POINT SOUNDINGS FROM THE 12Z
NAM SHOW RELATIVELY WEAK SHEAR AND MINIMAL INSTABILITY DUE TO WARMER
TEMPERATURES BETWEEN 700-925 MB, WHILE POINT SOUNDINGS FROM THE 12Z
GFS SHOW UPWARD OF 1000 J/KG AND MODEST UNIDIRECTIONAL SHEAR. THE
PLAN VIEW ON THE 09Z SREF SHOWS THE HIGHEST PROBABILITIES OF
INSTABILITY/SHEAR ACROSS SOUTHEASTERN COUNTIES. THE 12Z HREF ALSO
SHOWS SOME UPDRAFT HELICITY SWATHS, INDICATIVE OF ROTATING STORMS,
PRIMARILY TO THE EAST OF US-1. ALTHOUGH THE FORECAST AREA IS NOT
CURRENTLY IN A SPC CONVECTIVE RISK CATEGORY FOR TUESDAY, CANNOT RULE
OUT SOME ISOLATED STRONGER STORMS.
IN ADDITION, THE HEAVIER RAINFALL ACROSS THE FORECAST AREA SHOULD
SHIFT A LITTLE BIT FARTHER TO THE EAST ON TUESDAY. THE CURRENT FLOOD
WATCH FOR THE ENTIRE FORECAST AREA GOES THROUGH TUESDAY MORNING, BUT
HAVE MADE THE DECISION TO EXPAND THE WATCH TEMPORALLY ACROSS THE
EAST THROUGH TUESDAY NIGHT WHERE THE RAIN RATES COULD BE HIGHER WITH
THE POTENTIAL OF STRONG TO SEVERE STORMS.
TUESDAY SHOULD BE A LITTLE WARMER THAN TODAY, WITH HIGHS MOSTLY IN
THE MID TO UPPER 70S. LOWS WILL GENERALLY BE IN THE LOW TO MID 60S.
LONG TERM /WEDNESDAY THROUGH SUNDAY/
AS OF 445 AM MONDAY...
* LINGERING SHOWERS/STORMS WED-WED NIGHT, THEN MAINLY DRY UNTIL
LATE FRI
* TURNING HOT, WITH SCATTERED, POSSIBLY STRONG-SEVERE CONVECTION FRI-
SAT
A MID-LEVEL CYCLONE OVER THE OH VALLEY AT THE START OF THE PERIOD
WILL BECOME AN OPEN WAVE TROUGH WHILE WEAKENING AND LIFTING NEWD
ACROSS THE LWR GREAT LAKES AND MIDDLE ATLANTIC THROUGH THU NIGHT.
PROGRESSIVE SHORTWAVE RIDGING WILL MIGRATE FROM THE MS VALLEY TO THE
MIDDLE AND SOUTH ATLANTIC THROUGH THE SAME TIME, THEN OFFSHORE.
MEANWHILE, YET ANOTHER CLOSED AND CUTOFF LOW WILL DEVELOP ACROSS THE
NRN PLAINS AND NRN MS VALLEY AND DRIFT SLOWLY EWD ACROSS THE GREAT
LAKES AND SRN ON/QC THROUGH THE WEEKEND.
AT THE SURFACE, A TROUGH WILL LINGER OVER THE MIDDLE ATLANTIC AND
CAROLINAS THROUGHOUT THE PERIOD, WITH A WEAK COLD FRONTAL PASSAGE IN
CNTL NC POSSIBLE LATE SAT INTO EARLY SUN.
ABOVE AVERAGE PROBABILITIES OF CONVECTION WILL LINGER WITH THE
SLOWLY EXITING MID/UPR-LEVEL TROUGH AND CYCLONIC FLOW ALOFT MID-
WEEK, FOLLOWED BY A MAINLY DRY THU-INTO AT LEAST EARLY FRI, BENEATH
SHORTWAVE RIDGING AND RISING HEIGHTS ALOFT. CONVECTIVE CHANCES WILL
THEN INCREASE LATE FRI, AND ESPECIALLY FRI NIGHT, AS FALLING HEIGHTS
AND FORCING FOR ASCENT, ACCOMPANYING THE CUTOFF LOW OVER THE GREAT
LAKES, GLANCE THE SRN MIDDLE ATLANTIC. A BELT OF SEASONABLY STRONG,
35-45 KTS OF MID-LEVEL AT ITS BASE AND INTO PARTS OF THE SRN MIDDLE
ATLANTIC WOULD FAVOR ORGANIZED STORMS AND RISK OF SEVERE.
IT WILL OTHERWISE TURN WARMER, TO HOT PARTICULARLY FRI, WHEN
FORECAST TEMPERATURES WILL BE IN THE UPR 80S TO LWR 90S, AND WITH
HEAT INDEX VALUES IN THE UPR 90S TO NEAR 100 MAINLY IN THE SANDHILLS
AND SRN-CNTL COASTAL PLAIN.
AVIATION /18Z MONDAY THROUGH SATURDAY/
AS OF 1255 PM MONDAY...
MVFR TO IFR CONDITIONS WILL CONTINUE OVER THE NEXT 24 HOURS AS
ADDITIONAL ROUNDS OF MODERATE TO HEAVY RAIN MOVES ACROSS CENTRAL NC.
BRIEF DROPS TO LIFR WILL BE POSSIBLE AT ANY TERMINAL WITH ANY
HEAVIER DOWNPOUR. AS WE PIVOT TO THE OVERNIGHT PERIOD, EXPECT
CEILINGS TO GENERALLY TREND TO THE IFR/LIFR RANGE AS ADDITIONAL
SHOWERS/ISOLATED STORMS MOVE ACROSS THE AREA.
A BRIEF LIFT TO MVFR APPEARS LIKELY LATE IN THE 24 HR TAF PERIOD AT
ALL SITES (WITH KFAY POSSIBLY GOING VFR EARLY TUESDAY AFTERNOON).
HOWEVER, ADDITIONAL SCATTERED SHOWERS AND STORMS WILL BE POSSIBLE
THROUGH WEDNESDAY MORNING (HIGHEST CHANCES FOR STORMS WOULD BE AT
KFAY/KRWI AND MAYBE KRDU FROM LATE TUESDAY MORNING THROUGH THE
EVENING HOURS).
AFTER 18Z TUESDAY: DIURNALLY DRIVEN SCATTERED SHOWERS AND
THUNDERSTORMS WILL CONTINUE TUESDAY AFTERNOON THROUGH LATE WEEK.
EARLY MORNING STRATUS AND/OR FOG (IFR TO LIFR) WILL BE LIKELY.
RAH WATCHES/WARNINGS/ADVISORIES
FLOOD WATCH THROUGH TUESDAY MORNING FOR NCZ007>011-024>028-
041>043-078-089.
FLOOD WATCH THROUGH TUESDAY MORNING FOR NCZ021>023-038>040-
073>077-083>086-088.
SYNOPSIS...BADGETT
NEAR TERM...LUCHETTI
SHORT TERM...GREEN
LONG TERM...MWS
AVIATION...LUCHETTI/CBL
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