877
FXUS62 KRAH 152357
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
757 PM 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 /THROUGH TONIGHT/
AS OF 757 PM THURSDAY...
A SEVERE THUNDERSTORM WATCH WAS ISSUED A FEW HOURS AGO FOR MANY
NORTHERN COUNTIES IN THE FORECAST AREA BASED ON ANTICIPATED
CONVECTION, AND WHILE THUNDERSTORMS HAVE FIRED ACROSS THE EASTERN
THIRD OF NORTH CAROLINA, THE REST OF THE FORECAST AREA HAS REMAINED
DRY. HAVE ELECTED TO CANCEL THE WATCH FOR COUNTIES ALONG THE
INTERSTATE 40 CORRIDOR, LEAVING A HANDFUL OF COUNTIES TO THE
NORTHEAST IN THE WATCH. THE WATCH IS SCHEDULED TO GO THROUGH
MIDNIGHT, BUT CONSIDERING HOW EMPTY THE RADAR HAS BEEN, IT APPEARS
LIKELY THAT OTHER COUNTIES WILL BE CANCELLED EARLY. PREVIOUS
DISCUSSION FOLLOWS.
AS OF 311 PM THURSDAY...
* ISOLATED/WIDELY SCATTERED STRONG/SEVERE CONVECTION POSSIBLE
ACROSS THE NORTHERN PIEDMONT AND NORTHERN COASTAL PLAIN THIS
AFTERNOON/EARLY EVENING
SATELLITE IMAGERY THIS AFTERNOON DEPICTED AN EXTENSIVE CU FIELD
ACROSS CENTRAL NC, WITH SOME CU APPEARING AGITATED ACROSS THE
WAKE/JOHNSON/FRANKLIN/NASH VICINITY. FURTHER NORTH, AGITATED CU ARE
STARTING TO SHOW ACROSS THE VA/WV HIGH TERRAIN. WHILE CONSIDERABLE
CAPE HAS DEVELOPED ACROSS OUR AREA THIS AFTERNOON, VERY LITTLE
MID/UPPER FORCING IS PRESENT OVER THE EASTERN SEABOARD. AT THE SFC,
THIS MORNING'S WARM FRONT HAS MIGRATED FURTHER NORTH INTO SOUTH-
CENTRAL VA. GIVEN LITTLE UPPER OR SFC FORCING, ANY CONVECTION THAT
DEVELOPS THE NEXT FEW HOURS WILL LARGELY BE DRIVEN SOLELY BY BOUNDARY
LAYER DESTABILIZATION. THIS INITIAL CONVECTION IS FORMING WITHIN AN
AREA OF WEAKER MID-LEVEL LAPSE RATES. AS SUCH, THE HAIL THREAT WITH
THIS EARLIER CONVECTION (WHICH SHOULD MIGRATE EAST OF OUR AREA SOON)
LOOKS LESS SEVERE. BEYOND ~20-21Z, HOWEVER, CONVECTION SHOULD POP
OFF THE BLUE RIDGE MOUNTAINS IN CENTRAL VA AND POSSIBLY TRICKLE A
FEW ISOLATED CELLS DOWN INTO OUR AREA.
IF THIS CONVECTION CAN REACH OUR AREA, FORECASTED HODOGRAPHS AND MID-
LAPSE RATES WOULD FAVOR RIGHT-MOVING SUPERCELLS (ELONGATED AND
CLOCKWISE-CURVED BETWEEN 2-5 KM) CAPABLE OF PRODUCING LARGE HAIL
(POSSIBLY > 2 INCHES) AND DAMAGING WIND GUSTS.
ANY STRONGER STORMS WILL DISSIPATE WITH LOSS OF HEATING THIS
EVENING. OVERNIGHT SHOULD REMAIN RELATIVELY DRY, HOWEVER SHOWERS
ASSOCIATED WITH A DECAYING, UPSTREAM MCS MAY GENERATE SOME
MEASURABLE RAINFALL THROUGH SUNRISE ACROSS WESTERN AREAS. OTHERWISE,
SOME PATCHY FOG MAY BE POSSIBLE ACROSS NORTHERN AREAS EARLY FRIDAY
MORNING.
SHORT TERM /FRIDAY AND FRIDAY NIGHT/
AS OF 230 PM THURSDAY...
* A CONDITIONAL RISK OF SEVERE STORMS WILL EXIST ACROSS THE NRN HALF
OF CNTL NC ON FRI, BASED ON LOWER PREDICTABILITY, MESOSCALE
INFLUENCES FROM UPSTREAM CONVECTION ACROSS THE LWR OH VALLEY TODAY-
TONIGHT.
12Z GUIDANCE THIS MORNING CONTINUES TO HIGHLIGHT AN UNCERTAIN
FORECAST WRT TO CONVECTION FRIDAY. AN UPSTREAM, DECAYING MCS IS
STILL FORECAST BY SEVERAL MODELS (E.G. NAMNEST, HRRR, NSSL) TO
CRUISE ACROSS THE MOUNTAINS AND FOOTHILLS EARLY FRIDAY MORNING.
STRONG SFC GUSTS (POSSIBLY 35 TO 45 KTS) ASSOCIATED WITH IT'S COLD
POOL STILL LOOK PLAUSIBLE EARLY TO MID FRIDAY MORNING ACROSS THE
NORTHERN PIEDMONT. THIS SCENARIO WOULD FAVOR LESS CONVECTIVE
POTENTIAL LATER FRIDAY AFTERNOON, AS LINGERING COOLER AIR AND CLOUD
DEBRIS LIMIT SFC HEATING ACROSS NORTHERN AREAS. ALTERNATIVELY, THE
FV3 AND ARW CAMS CONTINUE TO SIMULATE THE MORNING MCS FURTHER NORTH
INTO VIRGINIA. THIS SCENARIO WOULD FAVOR STRONG HEATING ACROSS ALL
OF CENTRAL NC AND THE DEVELOPMENT OF STRONG CAPE BY FRIDAY
AFTERNOON. ANY CONVECTION THAT DEVELOPS IN THIS ENVIRONMENT WOULD
FAVOR EXPLOSIVE UPDRAFTS AND SUPERCELLS CAPABLE OF LARGE HAIL AND
DAMAGING WIND GUSTS. GIVEN THIS POTENTIAL SCENARIO, THE SPC HAS
INTRODUCED A MARGINAL RISK FOR SEVERE STORMS OVER OUR NORTHERN TIER
OF COUNTIES. HOWEVER, GIVEN SOME MODELS LIMIT AFTERNOON CONVECTION,
DECIDED TO MAINTAIN JUST SLIGHT CHANCE POPS ACROSS GENERALLY
NORTHERN LOCATIONS FRIDAY AFTERNOON AND EVENING.
DURING THE OVERNIGHT HOURS, YET ANOTHER ROUND OF UPSTREAM, DECAYING
MCSS ARE FORECAST TO MOVE INTO THE MOUNTAINS AND FOOTHILLS THROUGH
SUNRISE. LIKE CLOCKWORK, THERE IS LITTLE GUIDANCE CONSENSUS ON THE
EVOLUTION OF THESE FEATURES. HOWEVER, ITS WORTH NOTING THAT SOME
CAMS DO INDICATE THE POTENTIAL FOR ANOTHER ROUND OF STRONG SFC GUSTS
EMBEDDED WITHIN ASSOCIATED COLD POOLS EARLY SATURDAY MORNING. WORTH
WATCHING FOR SURE.
LONG TERM /SATURDAY THROUGH THURSDAY/
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.
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 /00Z FRIDAY THROUGH TUESDAY/
AS OF 755 PM THURSDAY...
24 HOUR TAF PERIOD: ASIDE FROM AN ISOLATED SHOWER OR TWO EAST OF
KRWI, THE REMAINDER OF THE EVE/NIGHT SHOULD BE LARGELY DRY AND VFR.
HOWEVER, CANNOT RULE OUT SOME SUB-VFR VSBYS INVOF KRWI, WHERE A
STORM OCCURRED EARLIER THIS AFT. WINDS SHOULD BECOME LIGHT AND
VARIABLE TONIGHT, THEN GENERALLY WSWWD AT 5-10 KTS FRI AFT.
BEYOND 12Z FRI: LOW CONFIDENCE FORECAST AS THERE IS STILL A FAIR
DEAL OF UNCERTAINTY WRT A POTENTIAL MCS, EXPECTED TO INTENSIFY AND
MOVE EWD ACROSS THE MID-MS VALLEY TONIGHT. SOME GUIDANCE SUGGEST THE
MCS COULD HOLD TOGETHER AS IT MOVES ACROSS THE MOUNTAINS AND INTO
THE TRIAD AS EARLY AS NOON, TRACKING EWD ALONG AND NORTH OF I-85
THROUGH THE AFT/EARLY EVE. OTHER GUIDANCE HAS THE MCS DECAYING AS IT
MOVES ACROSS THE MTNS AND KEEPS CONVECTION LARGELY SUPPRESSED OWNING
TO A FAIR DEAL OF DEBRIS CLOUDINESS FROM THE DECAYING MCS MOVING
ACROSS THE AREA EARLY/MID DAY. GIVEN THE UNCERTAINTY, WILL KEEP TAFS
AT ONE LINE FOR NOW, BUT A PERIOD OF STORMS/RESTRICTIONS MAY NEED TO
BE ADDED FOR FRI AFT/EVE WITH LATER FORECAST 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...GREEN/LUCHETTI
SHORT TERM...LUCHETTI
LONG TERM...DANCO
AVIATION...KC/CBL
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