143
FXUS62 KRAH 241020
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
620 AM EDT MON AUG 24 2026
WHAT HAS CHANGED
* THERE IS A MARGINAL TO SLIGHT RISK OF SEVERE STORMS OVER
SAMPSON, CUMBERLAND, AND WAYNE COUNTIES THIS AFTERNOON AND
EARLY EVENING.
KEY MESSAGES
AS OF 206 AM MONDAY...
1) THERE IS A CHANCE FOR SHOWERS AND THUNDERSTORMS THIS
AFTERNOON TO EARLY EVENING ALONG AND EAST OF THE I-95 CORRIDOR.
2) DIURNALLY MAXIMIZED CONVECTION RETURNS TO CENTRAL
NC AS EARLY AS WEDNESDAY, BUT MORE LIKELY THURSDAY INTO FRIDAY
BEFORE SHIFTING TOWARDS THE COAST THROUGH THE WEEKEND.
DISCUSSION
AS OF 206 AM MONDAY...
KEY MESSAGE 1... THERE IS A CHANCE FOR SHOWERS AND THUNDERSTORMS
THIS AFTERNOON TO EARLY EVENING ALONG AND EAST OF THE I-95 CORRIDOR.
SATELLITE IMAGERY AND SURFACE OBSERVATIONS INDICATE A WEAK
SURFACE LOW DEVELOPING OVER CENTRAL SC, WITH A STALLED COLD
FRONT EXTENDING FROM THE NC COASTAL PLAIN INTO CENTRAL SC.
DYNAMIC GUIDANCE INDICATES THE SURFACE LOW WILL TRACK EAST-
NORTHEAST TODAY INTO THE SANDHILLS AND CENTRAL/SOUTHERN COASTAL
PLAIN. AS IT DOES, THE STALLED FRONT IS EXPECTED TO BUCKLE
WESTWARD, POTENTIALLY REACHING AS FAR WEST AS THE WAKE/JOHNSTON
COUNTY LINE.
A SHARP MOISTURE GRADIENT REMAINS ACROSS THE STATE: THE 00Z MHX
SOUNDING HIGHLIGHTED A VERY MOIST AIRMASS OVER EASTERN NC,
CONTRASTED WITH MUCH DRIER AIR AT GSO (PWAT OF ~0.85 INCHES).
SURFACE DEWPOINTS IN THE MID-70S ALONG THE COAST UNDERSCORE THE HIGH
MOISTURE CONTENT EAST OF THE BOUNDARY. AN ENHANCED SEABREEZE
INTERACTION WITH THE FRONT AND SURFACE LOW WILL SERVE AS THE PRIMARY
TRIGGER FOR CONVECTIVE INITIATION, WITH RESULTANT OUTFLOWS LIKELY
DRIVING SECONDARY CELL DEVELOPMENT.
SPATIAL FOCUS & MODEL GUIDANCE: THE HIGHEST STORM COVERAGE IS
EXPECTED ALONG AND EAST OF I-95, EXTENDING FROM THE EASTERN
SANDHILLS INTO THE COASTAL PLAIN. MOST CAMS KEEP CONVECTIVE ACTIVITY
CONCENTRATED OVER THE SOUTHERN COASTAL PLAIN (PRIMARILY SAMPSON
AND WAYNE COUNTIES). HOWEVER, THE RRFS REPRESENTS A REASONABLE
WORST-CASE SCENARIO, BRINGING CONVECTION AS FAR WEST AS THE
HARNETT/CUMBERLAND COUNTY LINE. WHILE MODEL SPREAD LEAVES SOME
UNCERTAINTY REGARDING EXACT WESTERN EXTENT, THE THERMODYNAMIC
ENVIRONMENT ALONG AND EAST OF I-95 WILL EASILY SUPPORT SEVERE
STORMS, CHARACTERIZED BY MLCAPE OF 2000-3000 J/KG (HIGHEST IN
SAMPSON COUNTY) AND 30 KTS OF DEEP-LAYER SHEAR. SHOULD STORMS
INITIATE FURTHER NORTH NEAR RWI, EFFECTIVE SHEAR COULD REACH ~40
KTS UNDER THE INFLUENCE OF AN UPPER-LEVEL JET STREAK.
HAZARDS: SPC EXPANDED THE MARGINAL RISK FOR SEVERE THUNDERSTORMS,
FOCUSED MAINLY OVER SAMPSON AND WAYNE COUNTIES. THE PRIMARY
HAZARD WILL BE LOCALLY DAMAGING WIND GUSTS, ALTHOUGH A SECONDARY
HAIL THREAT IS ALSO POSSIBLE GIVEN STRAIGHT HODOGRAPHS. SPC HAS
ALSO MAINTAINED A 2-PERCENT TORNADO RISK, WHERE A SLIGHT RISK
OF SEVERE NOW EXISTS OVER FAR SOUTHERN SAMPSON; GIVEN WEAK BULK
LOW-LEVEL SHEAR, ANY BRIEF TORNADO THREAT WOULD BE STRICTLY NON-
SUPERCELLULAR, TIED TO LOCALIZED LOW-LEVEL VORTICITY STRETCHING
ALONG THE SURFACE LOW/BOUNDARY. SHOULD 12Z GUIDANCE AND AI
MODEL TRENDS CONTINUE SHIFTING WESTWARD, FURTHER EXPANSION OF
THE SEVERE RISK WESTWARD MAY BECOME NECESSARY.
DRIER, MORE COMFORTABLE CONDITIONS ARE EXPECTED TUESDAY AS HIGH
PRESSURE BUILDS IN FROM THE NORTH. LOWER DEWPOINTS WILL
MAINTAIN COMFORTABLE HUMIDITY LEVELS ACROSS CENTRAL NC. ISOLATED
STORM DEVELOPMENT WILL BE LARGELY SUPPRESSED, RESTRICTED TO THE
SEA BREEZE OVER SAMPSON OR CUMBERLAND COUNTIES. THE AGGRESSIVE
HRRR SOLUTION WAS DISCOUNTED IN FAVOR OF GLOBAL MODEL CONSENSUS,
WHICH DEPICTS A SUFFICIENTLY STABLE AIRMASS TO PREVENT
WIDESPREAD ACTIVITY.
KEY MESSAGE 2... DIURNALLY MAXIMIZED CONVECTION RETURNS TO
CENTRAL NC AS EARLY AS WEDNESDAY, BUT MORE LIKELY THURSDAY INTO
FRIDAY BEFORE SHIFTING TOWARDS THE COAST THROUGH THE WEEKEND.
A CLOSED MID/UPPER LEVEL LOW OVER SOUTHERN QUEBEC TUES MORNING WILL
CONTINUE TO SLOWLY PIVOT EAST-NORTHEAST AS ANOTHER SERIES OF
SHORTWAVES PARADE ACROSS GREAT LAKES AND SOUTHERN ONTARIO THROUGH
FRI. MOISTURE RETURNS IN THE LOW LVLS AS EARLY AS WED, WITH DEEPER
MOISTURE RETURN ON THURS, ALTHOUGH RICH TROPICAL MOISTURE APPEARS
LIMITED IN DURATION AS THE MID/UPPER LEVEL FLOW TURNS WEST-NORTHWEST
AGAIN OVER THE MID-ATLANTIC INTO THE CAROLINAS BY THIS WEEKEND.
NEVERTHELESS, THIS SHOULD SUPPORT DIURNALLY DRIVEN CONVECTION AS
SURFACE DEW POINTS IN THE 70S RETURN AND PWAT VALUES RISE BACK TO
AROUND OR SLIGHTLY-ABOVE NORMAL INTO THE WEEKEND. THERE MAY BE SOME
MIXING OUT OF DEW POINTS EACH AFTERNOON, ESPECIALLY OVER THE
PIEDMONT BACK INTO THE 60S WHICH MAY LIMIT THE MODERATE INSTABILITY
TO THE SANDHILLS AND COASTAL PLAIN.
THURS STILL APPEARS TO HAVE THE BEST CHANCE FOR MEASURABLE
PRECIPITATION WITH NEUTRAL H5 HEIGHT TENDENCIES AND POTENTIAL
INFLUENCE FROM ANY MCV'S FROM UPSTREAM CONVECTION OVER THE OHIO AND
TENNESSEE VALLEY'S. REASONABLE HIGH-END TOTALS FOR ANY GIVEN AREA
WILL BE AROUND 1" TO AS MUCH AS +2" BASED ON THE 12Z LREF. HOWEVER,
THESE AMOUNTS WILL NOT OCCUR EVERYWHERE, AS IS THE NATURE OF
SUMMERTIME CONVECTION, WITH MOST LOCATIONS LIKELY TO RECEIVE
SOMEWHERE BETWEEN TRACE AMOUNTS TO 0.5". SLOW EVOLVING LONGWAVE
TROUGHING TO THE WEST WILL FAVOR SOUTHWESTERLY MOISTURE TRANSPORT
OVER THE AREA AS EARLY AS WED AND CONTINUING INTO THURS NIGHT. THIS
PATTERN COULD BE CONDITIONALLY FAVORABLE FOR EXCESSIVE RAINFALL
ANYWHERE BUT HIGHLY DEPENDENT ON TRAINING STORMS TO DEVELOP.
AVIATION /12Z MONDAY THROUGH FRIDAY/
AS OF 620 AM MONDAY...
VFR CONDITIONS WILL GENERALLY PREVAIL ACROSS CENTRAL NC TERMINALS
THROUGH THE PERIOD, WITH THE PRIMARY EXCEPTION BEING KFAY.
AS A SURFACE LOW TRACKS NORTHWARD ALONG A STALLED FRONT IN EASTERN
NC THIS MORNING, ISOLATED SHOWERS AND A STORM MAY BE POSSIBLE UNTIL
13Z AT KFAY. HOWEVER, MOST OF THE STORMS ON RADAR PRESENTLY SHOULD
EXIT THE TERMINAL BY 12Z. HOWEVER, ADDITIONAL CONVECTION IS POSSIBLE
THIS AFTERNOON.
THIS AFTERNOON INTO THE EARLY EVENING, THE SURFACE LOW TRACKING
NORTHEAST COMBINED WITH A WESTWARD-BUCKLING FRONT AND SEA-BREEZE
WILL BRING A CHANCE FOR ISOLATED TO SCATTERED THUNDERSTORMS NEAR
KFAY. WHILE THE RRFS/HRRR/FV3 SHOW CONVECTION REACHING NEAR KFAY,
THE MAJORITY OF CAM GUIDANCE KEEPS ACTIVITY JUST EAST OF THE
TERMINAL, JUSTIFYING A LOW-END PROB30. ISOLATED STORMS ARE ALSO
POSSIBLE NEAR KRWI, BUT CONFIDENCE REMAINS TOO LOW TO INTRODUCE
TERMINAL RESTRICTIONS.
OUTLOOK: MORNING STRATUS AND FOG POTENTIAL WILL BE POSSIBLE AT
KFAY/KRWI TUESDAY AND WEDNESDAY MORNINGS. CONVECTIVE COVERAGE
WILL INCREASE MIDWEEK, PEAKING THURSDAY AND FRIDAY, WITH IMPACTS
POTENTIALLY LINGERING INTO EARLY SATURDAY.
RAH WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION...KREN/SWIGGETT
AVIATION...KREN
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page