295
FXUS62 KRAH 160732
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
330 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 THREAT 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 355 PM THURSDAY...
THE MID/UPPER LOW AND OCCLUDED SURFACE LOW WILL TRACK EAST ACROSS
SOUTHERN ONTARIO/QUEBEC AND THE GREAT LAKES ON SATURDAY AND SATURDAY
NIGHT, DRAGGING A COLD FRONT TO THE SOUTH THAT WILL PASS THROUGH
CENTRAL NC DURING THE AFTERNOON AND EVENING. MODEL GUIDANCE
INDICATES AN MCS WILL APPROACH FROM THE TN VALLEY ON FRIDAY NIGHT,
BUT WEAKENING SIGNIFICANTLY AS IT CROSSES THE APPALACHIANS AND
APPROACHES CENTRAL NC ON SATURDAY MORNING, WITH OUTFLOW SURGING OUT
AHEAD OF IT. MODELS STRUGGLE WITH DEPICTING THE STRENGTH AND TIMING
OF THESE MCS'S, ESPECIALLY THIS FAR OUT, AND THAT WILL BE CRITICAL
FOR THE SEVERE STORM THREAT LATER IN THE DAY. A WEAKER MCS THAT
PASSES THROUGH EARLIER ON SATURDAY WOULD FAVOR MORE DAYTIME HEATING
AND DESTABILIZATION COMPARED TO VICE VERSA. THE NAM NEST IS THE ONLY
HIGH-RES GUIDANCE THAT GOES OUT THIS FAR, AND IT DOES DEPICT AMPLE
INSTABILITY RESULTING IN A BROKEN LINE OF SHOWERS AND STORMS
DEVELOPING ALONG THE COLD FRONT FROM SATURDAY MID-AFTERNOON INTO THE
EVENING. HOWEVER, LOWER-RES GUIDANCE IS MOSTLY DRY, AND MOISTURE
WITH THE FRONT DOES NOT LOOK IMPRESSIVE, AS THE FLOW ALOFT IS FROM A
WESTERLY DIRECTION. FURTHERMORE, WE WILL ONLY GET WEAK UPPER FORCING
WITH THE LOW TRACKING SO FAR TO OUR NORTH. GFS/ECM/CMC ENSEMBLE MEAN
QPF CONTINUES TO TREND DRIER AND IS LESS THAN A TENTH OF AN INCH. SO
WHILE CONVECTIVE COVERAGE IS STILL UNCLEAR, THINK IT SHOULD BE
PRETTY ISOLATED, AND ONLY HAVE SLIGHT TO LOW CHANCE POPS. STILL,
THERE IS A CONDITIONAL THREAT OF A FEW STRONG TO SEVERE STORMS WITH
LARGE HAIL AND DAMAGING WINDS DEVELOPING ALONG AND AHEAD OF THE
FRONT, AS SURFACE-500 MB BULK SHEAR WILL BE AS HIGH AS 40-50 KTS.
ALSO CAN'T RULE OUT SOME STRONG COLD POOL INDUCED WIND GUSTS WITH
WHAT IS LEFT OF THAT MCS ON SATURDAY MORNING. SATURDAY'S
TEMPERATURES MAY BE KEPT DOWN IN THE MORNING BY OUTFLOW AND CLOUDS
FROM THE SYSTEM, BUT WE SHOULD STILL GET GOOD SURFACE HEATING IN THE
AFTERNOON AS CLOUDS BREAK AND WE GET STRONG SW WINDS AHEAD OF THE
FRONT (GUSTING UP TO 20-30 MPH EVEN OUTSIDE OF ANY STORMS). SO
FORECAST HIGHS ARE STILL MID-80S TO LOWER-90S, NOT QUITE AS WARM AS
FRIDAY, BUT HEAT INDICES IN THE MID-TO-UPPER-90S WILL STILL BE
POSSIBLE IN THE SE.
LONG TERM /SUNDAY THROUGH THURSDAY/
AS OF 355 PM THURSDAY...
THE MID-LEVEL FLOW WILL TURN NW FROM SUNDAY INTO TUESDAY, AS WE ARE
CAUGHT BETWEEN THE LOW SLOWLY DRIFTING EAST OVER NEW ENGLAND AND THE
CANADIAN MARITIMES AND RIDGING THAT STRENGTHENS AND BUILDS EAST FROM
THE MS VALLEY TO THE DEEP SOUTH AND TN VALLEY. AT THE SURFACE, A
BACKDOOR COLD FRONT LOOKS TO MOVE THROUGH CENTRAL NC ON SUNDAY
NIGHT. THIS FRONT THEN LOOKS TO LIFT BACK SLOWLY NORTH ON MONDAY AND
TUESDAY, AND LATEST GUIDANCE HAS TRENDED TOWARD THE FRONT LINGERING
MORE ON TOP OF OUR REGION INSTEAD OF TO OUR SW. PRECIPITATION
CHANCES COULD BE ENHANCED BY A SERIES OF MCS'S THAT MOVE OVERTOP THE
RIDGE AND THROUGH THE SOUTHERN MID-ATLANTIC. SO EXPECT GRADUALLY
INCREASING SHOWER AND STORM CHANCES EACH DAY, BUT THERE IS STILL
PLENTY OF UNCERTAINTY.
THE NEXT MID/UPPER LOW WILL MOVE EAST FROM THE CENTRAL PLAINS ON
TUESDAY, BUT MODELS DISAGREE ON THE PATTERN EVOLUTION AFTER. THE GFS
PICKS IT UP BY A NORTHERN STREAM LOW OVER THE GREAT LAKES AND IS
MORE PROGRESSIVE, WHILE THE ECMWF KEEPS THE SYSTEMS SEPARATE AND
THUS HANGS THEM BACK LONGER. THIS WILL HAVE A BIG IMPACT ON
PRECIPITATION CHANCES AS WELL AS TEMPERATURES, BUT IT LOOKS LIKE AN
ASSOCIATED COLD FRONT WILL MOVE THROUGH SOMETIME WEDNESDAY OR
THURSDAY. FOR NOW HAVE POPS INCREASING TO HIGH CHANCE TO LIKELY ON
WEDNESDAY, DECREASING SOMEWHAT ON THURSDAY AS THE GFS AND MOST OF
ITS ENSEMBLES ARE DRY BY THEN WHILE THE ECMWF AND CMC ARE STILL WET.
AS COOL HIGH PRESSURE EXTENDS SOUTH FROM THE HUDSON BAY INTO THE
EASTERN US, EXPECT AT LEAST SLIGHTLY COOLER TEMPERATURES FROM SUNDAY
INTO TUESDAY WITH HIGHS MAINLY IN THE 80S AND LOWS IN THE UPPER-50S
TO MID-60S. DEW POINTS WILL BE MORE TOLERABLE COMPARED TO NOW,
GENERALLY MID-50S TO LOWER-60S. A SHARP DROP TO BELOW-NORMAL
TEMPERATURES SHOULD OCCUR LATE NEXT WEEK ONCE THE WEDNESDAY/THURSDAY
COLD FRONT MOVES THROUGH.
AVIATION /06Z FRIDAY THROUGH TUESDAY/
AS OF 230 AM FRIDAY...
24 HOUR TAF PERIOD: AN ISOLATED SHOWER/STORM OR TWO REMAINS POSSIBLE
OVERNIGHT. OTHERWISE, WITH THE EXCEPTION FOR SOME VARIABLE
RESTRICTIONS AT FOG PRONE KRWI, ALL REMAINDER TAF SITES SHOULD
REMAIN VFR THROUGH DAYBREAK.
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 ISOLATED TO SCATTERED STORMS
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 HOLD TOGETHER, STRONG INSTABILITY AND SHEAR WOULD BE
CONDUCIVE FOR STRONG WIND GUSTS OF 30-50KT+, HAIL AND SUB-VFR
CONDITIONS FOR ANY NORTHERN TAF SITE(KINT, KGSO, KRDU, AND KRWI)THAT
TAKES A DIRECT HIT.
GIVEN THE UNCERTAINTY, WILL OMIT ANY MENTION OF STORMS AND
RESTRICTIONS AT THIS TIME. BUT A PERIOD OF STORMS/RESTRICTIONS MAY
NEED TO BE ADDED WITH LATER TAF ISSUANCES.
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...DANCO
LONG TERM...DANCO
AVIATION...CBL
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