146
FXUS62 KRAH 201131
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
731 AM EDT MON JUL 20 2026
WHAT HAS CHANGED
* IN AN ACTIVE PATTERN WITH DAILY THREATS OF SEVERE WIND AND
FLOODING FOR THE NEXT FEW DAYS, THERE IS NOW A SLIGHT RISK (LEVEL
2 OF 5) OF BOTH SEVERE THUNDERSTORMS WITH DAMAGING WET DOWNBURSTS
AND EXCESSIVE RAIN/FLASH FLOODING ACROSS CNTL NC TODAY.
KEY MESSAGES
AS OF 330 AM MONDAY...
1) IN AN ACTIVE PATTERN WITH DAILY THREATS OF SEVERE WIND AND
FLOODING FOR THE NEXT FEW DAYS, THERE IS NOW A SLIGHT RISK (LEVEL 2
OF 5) OF BOTH SEVERE THUNDERSTORMS WITH DAMAGING WET DOWNBURSTS AND
EXCESSIVE RAIN/FLASH FLOODING ACROSS CNTL NC TODAY.
2) CONTINUED PERIODS OF UNSETTLED WEATHER THIS WEEK AS A STALLED
FRONT LINGERS ACROSS NC.
DISCUSSION
AS OF 330 AM MONDAY...
KEY MESSAGE 1... IN AN ACTIVE PATTERN WITH DAILY THREATS OF SEVERE
WIND AND FLOODING FOR THE NEXT FEW DAYS, THERE IS NOW A SLIGHT RISK
(LEVEL 2 OF 5) OF BOTH SEVERE THUNDERSTORMS WITH DAMAGING WET
DOWNBURSTS AND EXCESSIVE RAIN/FLASH FLOODING ACROSS CNTL NC TODAY.
AN UPR WAVE/SHORTWAVE TROUGH, EVIDENT IN GOES-E WATER VAPOR DATA
FROM THE VIRGINIAS TO MIDDLE TN THIS MORNING, AND WHICH HAS
AMPLIFIED FROM THE UPR MS VALLEY AND UPR GREAT LAKES SINCE SUN
MORNING, WILL PIVOT SLOWLY ACROSS AND OFFSHORE THE SRN MIDDLE
ATLANTIC, CAROLINAS, AND GA THROUGH EARLY TONIGHT. IT WILL BE
PRECEDED BY MCVS, APPARENT IN REGIONAL RADAR DATA OVER THE NC
SANDHILLS AND SRN COASTAL PLAIN THIS MORNING AND OTHERS LIKELY TO
FORM FROM SUBSEQUENT CONVECTIVE CLUSTERS OVER CNTL AND ERN NC LATER
TODAY INTO EARLY TONIGHT.
IN THE LWR-LEVELS AND AT THE SURFACE, REGIONAL VWP AND SURFACE
OBSERVATIONAL DATA DEPICT A TROUGH AND ASSOCIATED FRONTAL ZONE IN
THE 925 MB TO SURFACE LAYER ROUGHLY ALONG THE NC/VA BORDER THIS
MORNING. THIS BOUNDARY, AND POST-FRONTAL STRATUS, WILL LIKELY
CONTINUE TO SETTLE SWD AND INTO THE NRN PIEDMONT AND NRN COASTAL
PLAIN OF NC THIS MORNING. IT WILL BE PRECEDED BY AT LEAST A COUPLE
OF AGGREGATE OUTFLOW BOUNDARIES EVIDENT IN RECENT AND EARLIER
REGIONAL RADAR AND SURFACE OBSERVATIONAL DATA FROM CNTL SC THROUGH
ERN NC AND ALSO OVER THE NC SANDHILLS AND SRN/WRN PIEDMONT.
THE SURFACE-925 MB FRONT, ONE THAT SHOULD BE STRENGTHENED THROUGH
DIFFERENTIAL DIABATIC HEATING ALONG RELATED LOW STRATUS AFTER
DAYBREAK, WILL PROBABLY SERVE AS A PRIMARY FOCUS FOR RENEWED DEEP
CONVECTIVE DEVELOPMENT WITH DIURNAL HEATING OF AN UNSEASONABLY
MOIST/HUMID AIRMASS FROM LATE MORNING THROUGH THIS EVENING. HOWEVER,
OTHER CELLS MAY DEVELOP AND CLUSTER ALONG THE AFOREMENTIONED OUTFLOW
BOUNDARIES AND ALSO ALONG A POSSIBLE SEPARATE DIFFERENTIAL HEATING
ZONE FROM MID-LEVEL CLOUD DEBRIS FROM THE AFOREMENTIONED MCV. ALL
WILL OCCUR IN A DEEPLY MOIST ENVIRONMENT CHARACTERIZED BY PWS OF
AROUND 2" (SLIGHTLY BELOW 2" AT GSO IN RECENT RAOBS AND SLIGHTLY
ABOVE 2" AT MHX), AND AMID ~10-20 KTS OF SWLY CLOUD LAYER AND 850 MB
FLOW, SUPPORTIVE OF SMALL UPWIND PROPAGATION/CORFIDI VECTORS AND
RELATED SLOW-MOVING/BACKBUILDING MULTI-CELL CLUSTERS ALONG THE
MYRIAD OF SURFACE BOUNDARIES IN PLACE. SCATTERED INSTANCES OF FLASH
FLOODING MAY RESULT, AS MAY DAMAGING, WET DOWNBURSTS.
WHILE FORECAST HEAT INDEX VALUES WILL PROBABLY AT LEAST BRIEFLY
REACH THE 100-105 F RANGE FROM THE SRN PIEDMONT TO THE SANDHILLS AND
SRN AND CNTL COASTAL PLAIN, THE MCV AND ASSOCIATED MID-LEVEL CLOUD
CANOPY MAY LINGER WELL INTO THE MORNING; AND UNCERTAINTIES EXIST
WITH HOW MUCH AND QUICKLY THE ENVIRONMENT WILL HEAT BEFORE
ADDITIONAL CONVECTION LIKELY DEVELOPS ALONG THE FEATURES NOTED
ABOVE. AS SUCH, FORECAST CONFIDENCE IS LOW IN HEAT INDICES
MEETING/EXCEEDING 105 F; AND NO ADDITIONAL HEAT ADVISORIES ARE
PLANNED AT THIS TIME FOR TODAY.
KEY MESSAGE 2... CONTINUED PERIODS OF UNSETTLED WEATHER THIS WEEK
AS A STALLED FRONT LINGERS ACROSS NC.
BROAD AND WEAK TROUGHING OVER THE EASTERN CONUS TODAY WILL BECOME
REINFORCED BY A MORE VIGOROUS SHORTWAVE TROUGH PIVOTING ACROSS THE
GREAT LAKES AND SOUTHERN QUEBEC ON TUES. A LOW-AMPLITUDE LIKELY
CONVECTIVELY ALTERED PERTURBATION RIPPLING THROUGH THE BASAL PORTION
OF THE TROUGH IS FORECAST TO SHIFT ACROSS THE OHIO VALLEY TUES
MORNING BEFORE POTENTIALLY SHIFTING ACROSS THE SOUTHERN MID-ATLANTIC
DURING PEAK HEATING. THERE ARE SOME NOTABLE TIMING DIFFERENCES WITH
THE LOW-PREDICITABILITY FEATURE, BUT NEVERTHELESS, ENHANCED WESTERLY
WINDS OF > 30 KTS ARE FORECAST TO SINK SOUTH AND INTO NORTH CAROLINA
AND OVERLAP A CONTINUED MOIST AND UNSTABLE ENVIRONMENT. ALTHOUGH
FLOW THROUGHOUT THE TROPOSPHERE IS NOT PARTICULARLY STRONG,
CONSISTENTLY VEERING WINDS WITH HEIGHT WILL SUPPORT CURVED
HODOGRAPHS CAPABLE OF PRODUCING TRANSIENT SUPERCELLS AND BOWING
SEGMENTS. ANY RIGHT-MOVING STORM WILL HAVE A STORM MOTION OF
SOUTHEAST AND INCREASE THE LIKELIHOOD THAT STORMS MAY DRIFT INTO OUR
REGION FROM VA. ALL HAZARDS WILL BE ON THE TABLE FOR TUESDAY,
ALTHOUGH DAMAGING STRAIGHT-LINE WINDS WILL BE THE MOST LIKELY
PRIMARY AND MORE WIDESPREAD HAZARD.
AN UPSTREAM SHORTWAVE TROUGH IS FORECAST TO CROSS THE MOUNTAINS
WEDNESDAY WITH AN ATTENDANT SURFACE COLD FRONT IN TOW. WITH PW'S
STILL AT OR NEAR 2" AND NEARLY 2000 J/KG OF MLCAPE AVAILABLE, STRONG
TO SEVERE STORMS ARE MORE THAN PLAUSIBLE WITH THE FRONT.
SIGNIFICANTLY LOWER PW'S WILL FOLLOW THE FRONT WITH SUBSTANTIALLY
LOWER PRECIP CHANCES THURSDAY THROUGH SATURDAY, ALTHOUGH MODEL
INCONSISTENCIES REGARDING HOW FAR SOUTH THE FRONT AND DRIER AIR PUSH
SOUTH RESULTS IN AN LOWER FORECAST CONFIDENCE IN A DRY SPELL;
ESPECIALLY WITH SUCH A WEAK AND PROGRESSIVE SURFACE HIGH AND
CLIMATOLOGICALLY APPROACHING THE WINDOW WHEN IT IS DIFFICULT FOR
FRONTS TO PROGRESS ALL THE WAY THROUGH THE CAROLINAS.
AVIATION /12Z MONDAY THROUGH FRIDAY/
AS OF 730 AM MONDAY...
AREAS OF IFR-MVFR STRATUS WILL LIKELY CONTINUE TO DEVELOP AND EXPAND
IN COVERAGE ACROSS SRN VA AND NRN NC THIS MORNING, ALONG AND BEHIND
A SURFACE FRONT/PRESSURE TROUGH THAT WILL SETTLE INTO N-CNTL NC
THROUGH THE MORNING. SHOWERS AND STORMS ARE LIKELY TO DEVELOP WITH
DIURNAL HEATING OF AN UNSEASONABLY MOIST/HUMID AIRMASS FROM LATE
MORNING THROUGH THIS EVENING - FOCUSED ALONG THE AFOREMENTIONED
SURFACE FRONT/PRESSURE TROUGH AND SECONDARILY ALONG OUTFLOW AND/OR
DIFFERENTIAL HEATING ALONG CLOUD EDGES.
OUTLOOK: AN UNSEASONABLY MOIST/HUMID AIRMASS, AND LIFT PERIPHERAL TO
THE MID-LATITUDE WESTERLIES THAT WILL DIP TO ATYPICALLY LOW
LATITUDES FOR THIS TIME OF YEAR WITHIN A TROUGH FROM THE GREAT LAKES
TO THE MIDDLE ATLANTIC, WILL FAVOR ABOVE AVERAGE CHANCES OF SHOWERS
AND STORMS AND ALSO OVERNIGHT STRATUS AND FOG - BOTH THROUGH WED.
RAH WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION...MWS/SWIGGETT
AVIATION...MWS
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page