549
FXUS62 KRAH 161030
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
625 AM EDT THU MAY 15 2025
SYNOPSIS
UPPER LEVEL DISTURBANCES MOVING ATOP AN UPPER LEVEL RIDGE BUILDING
ACROSS THE SE US WILL SUPPORT MAINLY DIURNAL SHOWERS AND STORMS AND
UNSEASONABLY HOT TEMPERATURES TO END THE WORK WEEK. A SERIES OF COLD
FRONTS WILL MOVE THROUGH THE REGION OVER THE WEEKEND.
NEAR TERM /TODAY AND TONIGHT/
AS OF 330 AM FRIDAY...
* THERE REMAINS A CONDITIONAL RISK FOR STRONG/SEVERE STORMS ACROSS
THE NORTHERN PIEDMONT AND NORTHERN COASTAL PLAIN THIS
AFTERNOON/EARLY EVENING
OVERVIEW:
STRONG UPPER LEVEL RIDGE CENTERED OVER THE EASTERN US WILL MOVE
OFFSHORE LATE IN THE DAY. A SHORTWAVE TROUGH ASSOCIATED WITH THE
UPPER CYCLONE MOVING INTO THE GREAT LAKES WILL APPROACH FROM THE
WEST LATE TONIGHT/EARLY SATURDAY.
TODAY:
MODEL SPREAD REMAINS HIGH, AND FORECAST CONFIDENCE REGARDING STORM
POTENTIAL THIS AFTERNOON AND EVENING CONTINUES TO BE LOW.
THE UPPER RIDGE COULD PROVE QUITE FORMIDABLE AGAIN TODAY. THE
EXCEPTION MAY BE ACROSS NORTHERN PORTIONS OF THE FORECAST AREA WHERE
SHORTWAVE VORT DISTURBANCES SPILLING ATOP THE RIDGE COULD SUPPORT A
CLUSTER OR TWO OF VERY STRONG AND SEVERE STORMS DURING THE AFTERNOON
AND EVENING.
STRONG DIURNAL HEATING(AFTERNOON HIGHS UPPER 80S TO LOWER 90S)
WITHIN THE SEASONABLY MOIST AIRMASS AND STEEP MID-LEVEL LAPSE
RATES(7.5-8 DEG C/KM)ASSOCIATED WITH THE EML LINGERING OVER THE MID
SOUTH AND SE US WILL CREATE A STRONGLY UNSTABLE ENVIRONMENT WITH
MLCAPE EXPECTED TO PEAK BETWEEN 2000-3000 J/KG. SHEAR IS ALSO QUITE
IMPRESSIVE WITH 0-3KM SHEAR FORECAST TO STRENGTHEN TO 35-40 KTS
DURING THE AFTERNOON AND EVENING. IF STORMS DO MAKE IT INTO THE
NORTHERN PIEDMONT AND NORTHERN COASTAL PLAIN, THE ROBUST INSTABILITY
AND STRONG SHEAR COULD ALLOW FOR INTENSE PERSISTENT UPDRAFTS AND
SUPERCELLS TO TRACK EAST ACROSS THE NORTHERN PIEDMONT AND NORTHERN
COASTAL PLAIN COUNTIES. LARGE +2" HAIL AND POTENTIALLY DESTRUCTIVE
STRAIGHT-LINE WINDS UP TO 75 MPH. AN ISOLATED TORNADO IS ALSO
POSSIBLE.
ALTERNATIVELY, THE RIDGE COULD SHIELD CENTRAL NC FROM THE STRONG
DEEP CONVECTION, DIVERTING THE SEVERE THREAT NORTH OF THE AREA,
LEAVING IT HOT WITH CONSIDERABLE MID AND HIGH CLOUDS ACROSS THE
AREA. SO AS YOU CAN SEE WE ARE DEALING WITH A VERY CONDITIONAL
THREAT FOR SEVERE STORMS TODAY. STAY VIGILANT AND MONITOR THE LATEST
WEATHER CONDITIONS.
TONIGHT: ANY CONVECTION SHOULD DISSIPATE OR MOVE EAST OF THE AREA
BEFORE MIDNIGHT. THE APPROACH OF THE UPPER TROUGH FROM THE WEST
COULD SUPPORT SOME WEAKENING CONVECTION MOVING INTO THE WESTERN
PIEDMONT TOWARDS SUNRISE. OTHERWISE, MOSTLY DRY OVERNIGHT WITH
RECORD WARMTH EXPECTED(SEE CLIMATE SECTION BELOW). LOWS 70 TO 75.
SHORT TERM /SATURDAY AND SATURDAY NIGHT/
AS OF 415 AM FRIDAY...
* MODERATE INSTABILITY AND STRONG WLY MID-LEVEL FLOW AND SHEAR
PROFILES WILL SUPPORT A CONDITIONAL RISK OF SEVERE STORMS ONCE
AGAIN SAT, ESPECIALLY FROM THE ERN SANDHILLS THROUGH THE COASTAL
PLAIN DURING THE AFTERNOON, BASED ON LOWER PREDICTABILITY,
MESOSCALE INFLUENCES FROM A DECAYING QLCS AND OUTFLOW THAT WILL
LIKELY BE MOVING ACROSS THE NC PIEDMONT AT THE START OF THE
PERIOD.
A MID/UPR-LEVEL CYCLONE WILL PROGRESS ACROSS THE LWR GREAT LAKES AND
TO NRN NY AND VT BY 12Z SUN. A SIGNIFICANT SHORTWAVE PERTURBATION
WILL SLIGHTLY PRECEDE THE CYCLONE AND PARTIALLY PHASE WITH AN
ENERGETIC SRN STREAM WHILE MOVING ACROSS AND OFFSHORE THE MIDDLE
ATLANTIC THROUGH SAT. A BAND OF CONVECTIVELY-ENHANCED VORTICITY,
PROBABLY EXTENDING FROM WRN PORTIONS OF THE SRN MIDDLE ATLANTIC AND
CAROLINAS SWWD INTO THE TN VALLEY, AND RELATED TO THE AFOREMENTIONED
DECAYING QLCS THERE DURING THE MORNING, WILL MOVE EWD AND ACROSS THE
CAROLINAS THROUGH EARLY-MID AFTERNOON. RELATED TO THE INFLUENCE OF
EACH, MOSTLY WEAK MID-LEVEL HEIGHT FALLS WILL RESULT OVER CNTL NC
THROUGHOUT THE PERIOD BUT MAXIMIZE MODESTLY AT 20-40 METERS AROUND
18Z. AN EXTENSIVE AND PRISTINE EML PLUME WILL INITIALLY BE IN PLACE
ACROSS MUCH OF THE SOUTHEAST BUT WILL MIGRATE EWD AND OFFSHORE AHEAD
OF THE TROUGH/CYCLONE, AND ALSO BECOME CONTAMINATED BY MULTIPLE
ROUNDS OF DEEP CONVECTION THROUGH ITS WRN PERIPHERY, INCLUDING INTO
THE TN VALLEY AND WRN CAROLINAS, BY THE START OF THE PERIOD.
AT THE SURFACE, SOME DEGREE OF AGGREGATE OUTFLOW WILL LIKELY BE IN
THE PROCESS OF MOVING ACROSS CNTL NC, PROBABLY INCREASINGLY-AHEAD OF
DECAYING, PARENT CONVECTION. WHERE IT SLOWS AND STALLS, AND HOW
STRONG IT REMAINS WHEN IT DOES SO, WILL LIKELY HAVE RAMIFICATIONS ON
SUBSEQUENT CONVECTIVE INITIATION AS CONVECTIVE TEMPERATURES ARE
REACHED BY EARLY-MID AFTERNOON. AT THIS TIME, THE GREATEST
CLUSTERING FROM CAM GUIDANCE ON ITS PROBABLE LOCATION WOULD FAVOR
THE SANDHILLS AND COASTAL PLAIN. A LEE TROUGH AND PROGRESSIVELY
DRIER WSWLY FLOW TO ITS WEST WILL ALSO DEVELOP AND MOVE EWD ACROSS
THE PIEDMONT DURING THE AFTERNOON-EVENING, FOLLOWED BY A WEAK COLD
FRONTAL PASSAGE SAT NIGHT
WHILE MESOSCALE UNCERTAINTIES YIELD LOWER THAN AVERAGE FORECAST
CONFIDENCE ON SENSIBLE WEATHER SPECIFICS, THE MOST LIKELY SCENARIO
RELATED TO THE PATTERN DESCRIBED ABOVE WILL BE FOR A BAND OF
GENERALLY WEAKENING CONVECTION AND OVERCAST, AND OUTFLOW WITH STRONG
WIND GUSTS UP TO 30-35 KTS, TO BE IN THE PROCESS OF MOVING ACROSS W-
CNTL NC EARLY IN THE DAY. ASSOCIATED STABILIZING INFLUENCE DURING
THE MORNING WOULD THEN DIMINISH AS LINGERING PRECIPITATION AND
CLOUDS DISSIPATE BY EARLY AFTERNOON, WITH THOSE INFLUENCES PERHAPS
NEVER REACHING THE ERN SANDHILLS AND COASTAL PLAIN, WHERE DIURNAL
HEATING WOULD BE MAXIMIZED BENEATH STILL RELATIVELY PRISTINE EML. IT
WILL BE THERE, WHERE THE AFOREMENTIONED OUTFLOW BOUNDARY MAY HAVE
ALSO SURGED AND STALLED, AND WHERE WIDELY SCATTERED STORMS WOULD BE
MOST LIKELY TO DEVELOP. SHEAR PROFILES WOULD FAVOR A SUPERCELLULAR
MODE WITH ATTENDANT RISKS OF LARGE HAIL AND DAMAGING WIND GUSTS. IT
SHOULD OTHERWISE BE UNSEASONABLY HOT AGAIN, WITH HIGHS IN THE UPR
80S-LWR 90S.
WHILE SAT NIGHT WILL FEATURE CLEARING INITIALLY, HIGH-LEVEL MOISTURE
IN WLY FLOW WILL PROBABLY RESULT IN A RETURN OF CIRROSTRATUS
CEILINGS SUN MORNING.
LONG TERM /SUNDAY THROUGH THURSDAY/
AS OF 445 AM FRIDAY...
A MID/UPR-LEVEL CYCLONE WILL MOVE SLOWLY ACROSS THE NORTHEAST AND
NEAR THE COAST OF ATLANTIC CANADA THROUGH MID NEXT WEEK, WHILE
ANOTHER DEVELOPS ACROSS THE INTERMOUNTAIN WEST AND THEN PROGRESSES
ACROSS THE ROCKIES AND PLAINS. THE LATTER, PRECEDED BY SHORTWAVE
RIDGING ACROSS THE SOUTHEAST EARLY IN THE WEEK, WILL THEN PROGRESS
ACROSS THE OH VALLEY AND LWR GREAT LAKES VICINITY BY WED-THU, DURING
WHICH TIME ITS INFLUENCE WILL BE MOST LIKELY TO IMPACT CNTL NC.
AT THE SURFACE, A CONVECTIVELY-REINFORCED FRONTAL ZONE WILL LIKELY
BECOME QUASI-STATIONARY FROM THE MID MS VALLEY OR UPR MIDWEST TO THE
SRN APPALACHIANS AND WRN CAROLINAS, WHILE CANADIAN HIGH PRESSURE
WILL EXTEND FROM ON TO THE MIDDLE ATLANTIC. A LEE CYCLONE WILL THEN
TRACK FROM THE CNTL/SRN PLAINS TO THE MIDDLE ATLANTIC BY WED-THU,
WITH TYPICAL MODEL TIMING DIFFERENCES AND FORECAST UNCERTAINTIES AT
THAT TIME RANGE.
THE SENSIBLE WEATHER RELATED TO THE PATTERN DESCRIBED ABOVE WILL
FEATURE CONTINUED UNSEASONABLY WARM CONDITIONS, AND MAINLY DRY ONES
WITH THE FOCUS OF CONVECTION INTO THE SRN APPALACHIANS AND WRN
CAROLINAS, THROUGH TUE. INCREASING CHANCES OF RAIN/CONVECTION WILL
THEN RESULT WED-WED NIGHT, AND POSSIBLY LINGER INTO THU, DEPENDING
UPON HOW QUICKLY THE CYCLONE ULTIMATELY MOVES THROUGH THE MIDDLE
ATLANTIC.
AVIATION /11Z FRIDAY THROUGH TUESDAY/
AS OF 630 AM FRIDAY...
24 HOUR TAF PERIOD:
FORECAST CONFIDENCE IS LOWER THAN NORMAL WRT TO STORM POTENTIAL
THIS AFTERNOON AND EVENING.
UPPER LEVEL DISTURBANCES SPILLING ATOP A STRONG UPPER LEVEL RIDGE IN
PLACE ACROSS THE REGION MAY SUPPORT ONE OR TWO STRONG TO SEVERE
STORM CLUSTERS ACROSS THE NORTHERN PORTIONS OF THE FORECAST AREA
THIS AFTERNOON AND EVENING. ALTERNATIVELY, THE UPPER RIDGE COULD
LARGELY SUPPRESS/STIFLE COMPRESSION, KEEPING THE AREA FREE OF
CONVECTION. SHOULD STORMS MAKE IT FAR ENOUGH SOUTH, STRONG
INSTABILITY AND SHEAR WOULD BE CONDUCIVE FOR STRONG WIND GUSTS OF 30-
50KT+, HAIL AND SUB-VFR CONDITIONS FOR THE NORTHERN TAF SITES(KINT,
KGSO, KRDU, AND KRWI).
A 35-45T LLJ MOVING THROUGH THE AREA TONIGHT COULD BRING A BRIEF
PERIOD OF LLWS TO ALL TAF SITES OVERNIGHT. AN AREA OF WEAKENING
CONVECTION IS EXPECTED TO APPROACH THE KINT AND KGSO TERMINALS
BETWEEN 09 TO 12Z SATURDAY.
OUTLOOK: CHANCES FOR DIURNAL ISOLATED TO SCATTERED SHOWERS AND
STORMS WILL CONTINUE THROUGH MUCH OF THE PERIOD. MORNING FOG AND LOW
STRATUS WILL BE POSSIBLE EACH MORNING, ESPECIALLY IN AREAS THAT
RECEIVED SIGNIFICANT RAINFALL THE PREVIOUS DAY.
RAH WATCHES/WARNINGS/ADVISORIES
NONE.
SYNOPSIS...CBL
NEAR TERM...CBL
SHORT TERM...MWS
LONG TERM...MWS
AVIATION...CBL
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page