034
FXUS62 KRAH 210638
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
238 AM EDT TUE JUL 21 2026
WHAT HAS CHANGED
* UPDATED THE AVIATION SECTION OF THE AFD.
KEY MESSAGES
AS OF 400 PM MONDAY...
1) A STALLED FRONTAL BOUNDARY WILL PRODUCE SHOWERS AND THUNDERSTORMS
OVER CENTRAL NORTH CAROLINA TODAY. LOCALLY HEAVY RAINFALL AND FLASH
FLOODING WILL BE POSSIBLE.
2) SHOWERS AND STORMS WITH LOCALLY DAMAGING WINDS AND HEAVY RAINFALL
ARE AGAIN POSSIBLE ON TUESDAY, BUT THIS THREAT SHOULD BE MOSTLY
CONFINED TO OUR NORTH.
3) UNSETTLED WEATHER WILL CONTINUE ON WEDNESDAY AND POSSIBLY INTO
LATE WEEK AS A COLD FRONT APPROACHES AND THEN SLOWLY CROSSES NC.
DISCUSSION
AS OF 400 PM MONDAY...
KEY MESSAGE 1... A STALLED FRONTAL BOUNDARY WILL PRODUCE SHOWERS AND
THUNDERSTORMS OVER CENTRAL NORTH CAROLINA TODAY. LOCALLY HEAVY
RAINFALL AND FLASH FLOODING WILL BE POSSIBLE.
A SLIGHT RISK (LEVEL 2 OF 5) FOR BOTH SEVERE THUNDERSTORMS AND
EXCESSIVE RAINFALL/FLASH FLOODING IS IN EFFECT ACROSS CENTRAL NC
TODAY. AN UPPER-LEVEL SHORTWAVE TROUGH AND ASSOCIATED MCVS WILL
PIVOT ACROSS THE REGION THROUGH TONIGHT. AT THE SURFACE, LINGERING
FRONTAL BOUNDARY JUST SOUTH OF THE NC/VA BORDER WILL INTERACT WITH
GOOD DIURNAL HEATING AND THE HUMID AIRMASS WITH PWATS OF ~2.0 INCHES
WILL CONTINUE TO TRIGGER MULTI-CELL CLUSTER STORMS ACROSS THE REGION
THIS AFTERNOON AND EVENING. THE PRIMARY HAZARDS WILL BE DAMAGING
WINDS ASSOCIATED WITH DOWNBURST AND LOCALIZED FLASH FLOODING FROM
SLOW-MOVING OR TRAINING STORMS. AREAS ACROSS THE PIEDMONT AND
NORTHERN COASTAL PLAIN WILL HAVE THE BEST CHANCE FOR STRONGER SLOW
MOVING STORMS THROUGH AT LEAST MIDNIGHT TONIGHT. AFTER THE STORMS
DISSIPATE AND THE FRONT LIFTS TO THE NORTH INTO VA, EXPECT LOW
STRATUS CLOUDS TO MOVE ACROSS THE AREA BEFORE CLEARING SKIES EARLY
TUESDAY MORNING.
KEY MESSAGE 2... SHOWERS AND STORMS WITH LOCALLY DAMAGING WINDS AND
HEAVY RAINFALL ARE AGAIN POSSIBLE ON TUESDAY, BUT THIS THREAT SHOULD
BE MOSTLY CONFINED TO OUR NORTH.
BROAD TROUGHING OVER THE EASTERN US WILL DEEPEN ON TUESDAY DUE TO A
SHORTWAVE MOVING ACROSS SOUTHERN ONTARIO AND QUEBEC. WEAK MID-LEVEL
HEIGHT FALLS WILL RESULT OVER THE MID-ATLANTIC, WHICH MAY REACH AS
FAR SOUTH AS NORTHERN NC DURING THE DAY. MEANWHILE A PERTURBATION
WITHIN THE TROUGH AND ASSOCIATED WEAK SURFACE LOW/TROUGH WILL RESULT
IN AN AREA OF ENHANCED SHOWERS AND STORMS OVER THE OH VALLEY ON
TUESDAY MORNING THAT PROGRESSES EAST INTO THE MID-ATLANTIC THROUGH
THE AFTERNOON AND EVENING.
THE ABOVE FEATURES WILL COMBINE WITH A MOIST AND MODERATELY UNSTABLE
AIR MASS (PW VALUES 100-125% OF NORMAL AND MLCAPE VALUES OF 1500-
2500 J/KG) TO RESULT IN A CHANCE FOR ISOLATED TO SCATTERED SHOWERS
AND STORMS OVER CENTRAL NC ON TUESDAY AFTERNOON AND EVENING.
HOWEVER, PRECIPITATION CHANCES WILL MOSTLY BE CONFINED TO OUR
NORTHERN COUNTIES AS GUIDANCE DEPICTS A WEDGE OF RELATIVELY DRIER
AIR (PW VALUES OF 1.5-2") MOVING ACROSS OUR SOUTH AS TROPICAL
DEPRESSION TWO SLOWLY DRIFTS WEST NEAR THE NORTHERN GULF COAST. MID-
LEVEL FLOW WILL INCREASE WITH THE DEEPENING TROUGH, AND 30-40 KTS OF
BULK SHEAR IS POSSIBLE ACROSS OUR FAR NORTH. THUS THE NORTHERN
PIEDMONT AND NORTHERN COASTAL PLAIN ARE WHERE SPC HAS A SLIGHT
(LEVEL 2 OF 5) RISK FOR SEVERE WEATHER AND WPC HAS A MARGINAL TO
SLIGHT (LEVELS 1-2 OF 4) RISK FOR EXCESSIVE RAINFALL. HOWEVER,
CAPPED POPS AT CHANCE GIVEN THE BEST FORCING WILL BE ACROSS VA AND
COVERAGE IN THE CAMS DOES NOT LOOK WIDESPREAD. SIMILAR TO RECENT
DAYS, THE MAIN SEVERE THREAT WILL BE DAMAGING STRAIGHT-LINE WINDS.
ADDITIONAL ISOLATED SCATTERED CONVECTION WILL BE POSSIBLE ON TUESDAY
NIGHT AS A PREFRONTAL SURFACE TROUGH SETS UP AHEAD OF A STRONG COLD
FRONT OVER THE OH VALLEY. ONCE AGAIN THIS CHANCE IS MOSTLY ACROSS
OUR NORTH, AND THE SEVERE THREAT WILL BE LESS WITH THE LOSS OF
DAYTIME HEATING.
KEY MESSAGE 3... UNSETTLED WEATHER WILL CONTINUE ON WEDNESDAY AND
POSSIBLY INTO LATE WEEK AS A COLD FRONT APPROACHES AND THEN SLOWLY
CROSSES NC.
AS MID/UPPER TROUGHING WITH EMBEDDED SHORTWAVE IMPULSES REMAINS IN
PLACE ACROSS THE EASTERN US ON WEDNESDAY, A STRONG COLD FRONT WILL
APPROACH AND THEN SLOWLY BEGIN TO CROSS CENTRAL NC FROM THE NW ON
WEDNESDAY EVENING/NIGHT. WEAK TO MODERATE INSTABILITY IS AGAIN
EXPECTED TO DEVELOP, THOUGH IT MAY BE SOMEWHAT MITIGATED BY MORNING
CLOUD COVER. STILL, MOISTURE ALONG AND AHEAD OF THE FRONT LOOKS
PLENTIFUL WITH PW VALUES OF 2-2.5 INCHES. SO THE PREFRONTAL TROUGH
MAY PROVIDE A FOCUS FOR AFTERNOON CONVECTION, FOLLOWED BY A LINE OF
SHOWERS AND STORMS ASSOCIATED WITH THE COLD FRONT MOVING THROUGH
FROM NW TO SE ON WEDNESDAY EVENING/NIGHT. POPS ARE CATEGORICAL
ACROSS THE ENTIRE REGION, AND WPC HAS ALL OF CENTRAL NC IN A SLIGHT
(LEVEL 2 OF 4) RISK FOR EXCESSIVE RAINFALL. QPF IS IN THE 1-2 INCH
RANGE ON AVERAGE, AND LOCALLY HIGHER AMOUNTS WILL BE POSSIBLE. DEEP-
LAYER SHEAR OF 30-40 KTS COULD RESULT IN SOME STORMS BECOMING STRONG
TO SEVERE, AND OUR ENTIRE REGION IS ALSO IN A SLIGHT (LEVEL 2 OF 5)
RISK FOR SEVERE WEATHER. DAMAGING WINDS WILL AGAIN BE THE MAIN
THREAT.
UNCERTAINTY INCREASES FOR LATE WEEK AS MODELS DIFFER ON WHETHER THE
COLD FRONT IS ABLE TO PUSH SOUTH ENOUGH TO CLEAR ALL OF CENTRAL NC
OR WHETHER IT WILL GET HUNG UP OVER OUR REGION. BEHIND THE FRONT,
MUCH DRIER AIR WILL BRING CLEARING AND MUCH LOWER PRECIPITATION
CHANCES. OVERALL IT LOOKS LIKELY FOR SHOWERS AND STORMS TO CONTINUE
IN OUR SE ON THURSDAY, BUT THE NW MAY BE LARGELY DRY. BY FRIDAY AND
SATURDAY, THE GFS SAGS THE FRONT TO OUR SOUTH AND KEEPS ALL OF
CENTRAL NC MAINLY DRY, WHILE THE ECMWF AND CMC ARE SLOWER WITH THE
FRONT AND KEEP US WETTER. GIVEN HOW DIFFICULT IT CAN BE FOR FRONTS
TO PASS THROUGH THIS TIME OF YEAR, LIKELY POPS IN THE SE STILL SEEM
WARRANTED, BUT THIS COULD CHANGE AS WE GET CLOSER. THERE IS BETTER
AGREEMENT IN DRIER CONDITIONS BY SUNDAY AND MONDAY AS THE MID/UPPER
TROUGHING FINALLY PUSHES TO OUR EAST AND THE FLOW ALOFT TURNS
NORTHWESTERLY.
AVIATION /06Z TUESDAY THROUGH SATURDAY/
AS OF 230 AM TUESDAY...
ASIDE FROM A CHANCE OF DIURNAL CUMULUS CLOUD BASES THAT MAY DEVELOP
WITH SCT-BKN COVERAGE IN MVFR RANGE BETWEEN 14-17Z, PRIMARILY VFR
CONDITIONS ARE EXPECTED AMID STRENGTHENING, SSWLY LOW-LEVEL FLOW
THAT WILL FAVOR SURFACE GUSTS TO AROUND 20 KTS OR SO WITH DAYTIME
HEATING AND THE POSSIBILITY OF MARGINAL LOW-LEVEL WIND SHEAR TONIGHT-
WED MORNING. THE COVERAGE OF SHOWERS/STORMS SHOULD BE LESS TODAY
VERSUS MON, SINCE THE FRONTAL ZONE AND CONVERGENCE AXIS FROM MON HAS
WEAKENED AND SHIFTED NWD ACROSS THE MIDDLE ATLANTIC. THERE WILL,
HOWEVER, BE A CHANCE OF AT LEAST A FEW CELLS AT FAY FROM THE SEA
BREEZE AND SUBSEQUENT OUTFLOW THIS AFTERNOON AND ALSO AT INT/GSO
THIS AFTERNOON-EVENING FROM THE PIEDMONT TROUGH AND/OR OUTFLOW FROM
UPSTREAM CONVECTION ACROSS THE VIRGINIAS.
OUTLOOK: AN OUTFLOW-REINFORCED FRONTAL ZONE AND FOCUS FOR TRAINING
CONVECTION AND FLIGHT RESTRICTIONS WILL SETTLE VERY SLOWLY SWD INTO
THE NRN NC PIEDMONT LATE TONIGHT AND BECOME QUASI-STATIONARY OVER
CNTL NC THROUGH WED NIGHT. WHILE THE SURFACE FRONT WILL PROBABLY
SETTLE INTO SC AND SERN NC THU-FRI, "OVERRUNNING" LIFT ATOP THE
FRONTAL ZONE WILL FAVOR CONTINUED ABOVE AVERAGE CHANCES OF FLIGHT
RESTRICTIONS AND RAIN/STORMS THROUGH THE END OF THE WEEK, WITH
HIGHER CHANCES AT ERN SITES VERSUS WRN ONES.
RAH WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION...CA/DANCO
AVIATION...MWS
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