315
FXUS62 KRAH 160632
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
230 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 /THROUGH TONIGHT/
AS OF 950 PM THURSDAY...
THE SEVERE THUNDERSTORM WATCH HAS BEEN CANCELLED FOR THE ENTIRE
FORECAST AREA. SHOWERS AND THUNDERSTORMS ACROSS THE EASTERN PORTION
OF THE FORECAST AREA HAVE FALLEN APART. HOWEVER, SEVERAL RUNS OF THE
HRRR SHOW THE POTENTIAL FOR SOME SHOWERS TO MOVE INTO WESTERN
PORTIONS OF THE FORECAST AREA LATE TONIGHT TOWARD SUNRISE, AND HAVE
ADDED SOME SLIGHT CHANCE POPS TO ACCOUNT FOR THAT. IN ADDITION, SOME
PATCHY FOG CANNOT BE RULED OUT CONSIDERING THERE HAS NOT BEEN A
CHANGE IN AIRMASS AND THERE IS PLENTIFUL LOW LEVEL MOISTURE. LOWS
WILL BE IN THE MID AND UPPER 60S.
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 /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...GREEN
SHORT TERM...LUCHETTI
LONG TERM...DANCO
AVIATION...CBL
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