156
FXUS62 KRAH 141903
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
302 PM EDT WED MAY 14 2025
SYNOPSIS
AN UPPER LEVEL TROUGH WILL MOVE THROUGH THE REGION THROUGH TONIGHT.
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 WEEK.
NEAR TERM /THROUGH TONIGHT/
AS OF 300 PM WEDNESDAY...
CONVECTION THUS FAR TODAY HAS BEEN SUB-SEVERE, WITH THE STRONGEST
GUST OF 30 KTS OBSERVED AT KRDU EARLIER. AS THIS BROKEN LINE OF
SHOWERS AND STORMS MOVE EAST INTO THE I-95 CORRIDOR, THERE REMAINS
THE POTENTIAL FOR A FEW ISOLATED CELLS TO GROW STRONG TO SEVERE
(CAPE IS FORECAST TO REACH 3000 J/KG OVER THIS VICINITY IN THE NEXT
FEW HOURS). OUTFLOW VIA SEA-BREEZE INDUCED CONVECTION ALONG THE
COAST FROM EARLIER IS ALSO RACING TOWARDS OUR BROKEN LINE OF STORMS.
AS SUCH, OUTFLOW COLLISIONS IN THE COASTAL PLAIN MAY ALSO BRIEFLY
ENHANCE UPDRAFTS THE NEXT FEW HOURS. THE MAIN THREATS REMAIN
ISOLATED DAMAGING WIND GUSTS AND PERHAPS SOME LARGER HAIL. OVERALL
THOUGH, THE SEVERE RISK REMAINS LOW TODAY AND THIS EVENING.
CAMS ARE STILL GENERATING SOME ADDITIONAL SHOWERS/ELEVATED
CONVECTION LATER TONIGHT THROUGH EARLY THURSDAY MORNING. HOWEVER,
THE BULK OF PRECIPITATION SHOULD WANE WITH LOSS OF HEATING THIS
EVENING. OTHERWISE, EXPECT PATCHY TO LOCALLY DENSE FOG TO FORM
ACROSS NORTHERN AREAS AGAIN TONIGHT.
SHORT TERM /THURSDAY AND THURSDAY NIGHT/
AS OF 430 AM WEDNESDAY...
12Z GUIDANCE THIS MORNING HAS DONE LITTLE IN TERMS OF CHANGING OUR
THINKING ABOUT HOW THURSDAY WILL EVOLVE. THERE REMAINS UNCERTAINTY
WRT TO COVERAGE THURSDAY AFTERNOON, ESPECIALLY GIVEN THE INFLUENCE
OF THE APPROACHING UPPER RIDGE. IF CONVECTION DOES REACH CENTRAL NC,
IT STILL APPEARS TO BE MOST LIKELY OVER THE NORTHERN PIEDMONT AND
NORTHERN COASTAL PLAIN LATER IN THE DAY. DECIDED TO MAINTAIN JUST
CHANCE POPS IN THIS VICINITY CENTERED AROUND MID TO LATE AFTERNOON
AND EARLY EVENING. OTHERWISE, THE DESCRIPTION OF POTENTIAL HAZARDS
AND ASSOCIATED RATIONALE REMAINS ACCURATE FROM THE PREVIOUS
DISCUSSION LISTED BELOW.
PREVIOUS DISCUSSION FROM 430 AM...
DOWNSTREAM OF A MID/UPR-LEVEL CYCLONE THAT WILL DEVELOP AND DEEPEN
ACROSS THE NRN PLAINS AND UPR MS VALLEY, PROGRESSIVE SHORTWAVE
RIDGING FROM THE LWR MS TO OH VALLEYS AT THE START OF THE PERIOD
WILL MIGRATE EWD AND ACROSS THE MIDDLE AND SOUTH ATLANTIC THROUGH
12Z FRI. SEASONABLY STRONG NWLY TO WNWLY MID-LEVEL FLOW WILL RESULT
AND PREVAIL ACROSS THE SRN MIDDLE ATLANTIC AND CAROLINAS, AS WILL
WARM AIR ADVECTION MAXIMIZED IN THE 700-850 MB LAYER THAT WILL
PRECEDE THE ARRIVAL OF AN EXTENSIVE ELEVATED MIXED LAYER PLUME FROM
THE SRN PLAINS AND MEXICAN PLATEAU.
AT THE SURFACE, A WARM FRONT WILL STRENGTHEN AND RETREAT NEWD ACROSS
THE OH VALLEY AND VIRGINIAS, WHILE BROAD TROUGHING WILL OTHERWISE
REMAIN ACROSS THE SRN MIDDLE ATLANTIC AND CAROLINAS.
THE AFOREMENTIONED WAA REGIME MAY SUPPORT AN ONGOING AREA OF
ELEVATED CONVECTION OVER OR NEAR CNTL NC THU MORNING, BEFORE MOVING
EWD AND OFFSHORE THROUGH MIDDAY. THAT WAA REGIME, INCLUDING THROUGH
THE LOW-LEVELS WITH THE AFOREMENTIONED SURFACE WARM FRONTAL RETREAT,
WILL LIKELY SPREAD NWD ACROSS THE VIRGINIAS COINCIDENT WITH DAYTIME
HEATING. A SEPARATE AREA OF CONVECTION WILL PROBABLY RESULT AND
DEVELOP ALONG AND EAST OF THE BLUE RIDGE IN VA, WITH OTHER, MORE-
ISOLATED CELLS ACROSS THE NC NE PIEDMONT AND NRN COASTAL PLAIN - ALL
WITH A GENERALLY SEWD STORM MOTION THAT WOULD FAVOR SLIGHT TO LOW
CHANCE POP ROUGHLY ALONG AND NORTH OF I-40 DURING THE AFTERNOON-
EVENING. FORECAST HODOGRAPHS ARE ELONGATED AND CLOCKWISE-CURVED
PARTICULARLY BETWEEN 2-5 KM, WITH WEAKER FLOW IN THE LOWEST
KILOMETER. ASSOCIATED SHEAR PROFILES COMBINED WITH UPR-END MODERATE
INSTABILITY (IE. 2000-2500 J/KG), OWING TO THE PRESENCE OF STEEP MID-
LEVEL LAPSE RATES WITHIN THE EML, ATOP A STRONGLY-HEATED (INTO THE
MID/UPR 80S F) AND UNSEASONABLY MOIST BOUNDARY LAYER, WOULD FAVOR
SUPERCELLS WITH LARGE HAIL (SOME SIGNIFICANT >2") AND DAMAGING WIND
GUSTS.
WHILE CONVECTIVE AND ASSOCIATED DEBRIS CLOUDS SHOULD CLEAR THROUGH
MIDNIGHT, A PLUME OF MID/HIGH-LEVEL MOISTURE WILL OVERSPREAD THE
REGION FRI MORNING, WITH LOW TEMPERATURES MOSTLY MID-UPR 60S.
LONG TERM /FRIDAY THROUGH TUESDAY/
AS OF 500 AM TUESDAY...
THE MODELS ARE IN GOOD AGREEMENT WITH THE PROGRESSION OF A MID/UPR-
LEVEL CYCLONE ACROSS THE GREAT LAKES FRI THROUGH THE WEEKEND, WITH
INCREASING MODEL SPREAD REGARDING HOW QUICKLY IT MOVES ACROSS THE
NORTHEAST AND LINGERS NEAR OR OFFSHORE ATLANTIC CANADA THROUGH THE
MIDDLE OF NEXT WEEK. WHILE IT PROGRESSES ACROSS THE GREAT LAKES
EARLY IN THE PERIOD, GLANCING HEIGHT FALLS, THE STREAM OF AN
ENERGETIC SRN BRANCH JET, AND THE CONTINUED PRESENCE AND INFLUENCE
OF AN EML PLUME, WILL ALL RESULT ACROSS NC FRI-SAT. A HIGH AMPLITUDE
RIDGE WILL THEN PROGRESS SLOWLY EWD FROM THE PLAINS AND MS VALLEY
SUN TO THE SOUTHEAST AND GREAT LAKES THROUGH EARLY-MID NEXT WEEK.
AT THE SURFACE, A LEE TROUGH OVER THE SRN MIDDLE ATLANTIC AND
CAROLINAS FRI-SAT WILL PRECEDE THE PASSAGE OF A LEAD, WEAK COLD
FRONTAL PASSAGE IN CNTL NC SAT NIGHT. A STRONGER, REINFORCING COLD
FRONT WILL FOLLOW AND SETTLE SOUTH ACROSS CNTL NC PROBABLY SUN
NIGHT. THAT FRONT WILL THEN LIKELY STALL AND BECOME QUASI-STATIONARY
FROM THE SRN APPALACHIANS NWWD TO THE UPR MS VALLEY EARLY TO MID
NEXT WEEK, EQUATORWARD OF HIGH PRESSURE THAT WILL EXTEND FROM E-CNTL
CANADA TO THE MIDDLE ATLANTIC.
IT APPEARS INCREASINGLY-LIKELY THAT THE DRY AND CAPPING EML
INFLUENCE, AND DEEP LAYER WLY TO WSWLY FLOW THAT WILL INCLUDE A
CONSIDERABLE DOWNSLOPE COMPONENT IN THE LEE OF THE APPALACHIANS,
WILL LIMIT THE PROBABILITY OF DEEP CONVECTION OVER CNTL NC FRI-SAT.
THE EXCEPTION WILL BE PRIMARILY OVER THE FAR NRN NC PIEDMONT, WHERE
HEIGHT FALLS AND FORCING FOR ASCENT WILL BE MAXIMIZED AT THE BASE OF
THE PASSING CYCLONE ACROSS THE GREAT LAKES. THE AIRMASS OVER CNTL NC
WILL OTHERWISE BE HOT, WITH HIGH TEMPERATURES BOTH DAYS IN THE UPR
80S TO LWR-MID 90S.
PROGRESSIVELY LESS HOT, BUT STILL UNSEASONABLY WARM CONDITIONS, WILL
FOLLOW IN THE POST-FRONTAL REGIME ACROSS CNTL NC SUN THROUGH MID-
WEEK, ALONG WITH LOW PRECIPITATION CHANCES THAT WILL BE SHUNTED SWWD
AND NEARER THE STALLED FRONTAL ZONE ACROSS THE SRN APPALACHIANS AND
WRN CAROLINAS.
AVIATION /18Z WEDNESDAY THROUGH MONDAY/
AS OF 127 PM WEDNESDAY...
SCATTERED SHOWERS AND STORMS HAVE BLOSSOMED ACROSS CENTRAL NC EARLY
THIS AFTERNOON. THIS ACTIVITY SHOULD CONTINUE TO MIGRATE EASTWARD
WITH TIME THROUGH THIS EVENING. EXPECT BRIEF PERIODS OF SUB-VFR
CONDITIONS AT ALL TAF SITES IF IMPACTED BY ANY CONVECTION, WITH THE
BEST CHANCES BEING AT KRDU/KFAY/KRWI THROUGH THIS EVENING.
OTHERWISE, ADDITIONAL SHOWERS AND ELEVATED CONVECTION WILL BE
POSSIBLE OVERNIGHT, WITH BEST CHANCES AT KINT/KGSO.
EXPECTING FOG/STRATUS TO RE-DEVELOP TONIGHT AND POSSIBLY IMPACT THE
NORTHERN TERMINALS. ANY FOG/STRATUS SHOULD LIFT BY EARLY TO MID
THURSDAY MORNING.
OUTLOOK: CHANCES FOR DIURNAL 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...LUCHETTI
SHORT TERM...LUCHETTI/MWS
LONG TERM...MWS
AVIATION...LUCHETTI/CBL
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