312
FXUS62 KRAH 151832
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
231 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 /TODAY AND TONIGHT/
AS OF 1049 AM THURSDAY...
* ISOLATED/WIDELY SCATTERED STRONG/SEVERE CONVECTION POSSIBLE
ACROSS THE NORTHERN PIEDMONT AND NORTHERN COASTAL PLAIN THIS
AFTERNOON/EARLY EVENING
LITTLE UPDATES THIS MORNING AS THE FORECAST IS ON TRACK. SFC
OBSERVATIONS THIS MORNING DEPICTED A NORTHWARD ADVANCING WARM FRONT
BEHIND THE SLOWLY DECAYING STRATUS/FOG SHIELD IN THE NORTHERN
PIEDMONT/COASTAL PLAIN. THIS FEATURE WILL CONTINUE TO RIDE NORTH
SOMEWHERE INTO THE SOUTH-CENTRAL VA/NORTH-NORTHEASTERN NC LATER THIS
AFTERNOON. EMBEDDED WITHIN INCREASING WNWLY FLOW ALOFT AND A
SUBSTANTIALLY JUICY ATMOSPHERE, MID-LEVEL IMPULSES WILL INITIATE
CONVECTION OVER THE BLUE RIDGE MOUNTAINS IN VA EARLY THIS AFTERNOON.
A FEW ISOLATED STORMS MAY TRICKLE DOWN INTO OUR NORTHERN COASTAL
PLAIN/PIEDMONT AS THESE UPSTREAM CELLS INTERACT WITH THE ADVANCING
WARM FRONT. THERE REMAINS UNCERTAINTY, HOWEVER, WITH HOW MUCH
COVERAGE WE MAY ACTUALLY SEE AS SOME CAMS SIMULATE DRIER SOLUTIONS.
IF CONVECTION CAN REACH OUR AREA, FORECASTED HODOGRAPHS 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. FORECAST SOUNDINGS ACROSS NORTHERN AREAS
INDICATE VERY LIMITED LOW-LEVEL SHEAR, AND AS SUCH, THINK THE BETTER
TORNADO THREAT IS MORE-SO UP INTO VA TODAY. HOWEVER, IF THE WARM
FRONT LINGERS ACROSS OUR NORTHERN AREAS, THERE WOULD REMAIN SOME
CONCERN FOR A BRIEF ISOLATED TORNADO WHEREVER SFC WINDS MAY BACK
JUST AHEAD OF THE WARM FRONT.
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.
PREVIOUS DISCUSSION FROM 350 AM...
TODAY:
UPPER LEVEL RIDGING WILL BUILD EASTWARD TODAY, BRINGING MODEST 500
MB HEIGHT RISES(40 M) AND SUPPRESSING WIDESPREAD CONVECTION.
HOWEVER, STRONG DIURNAL HEATING(AFTERNOON HIGHS MID/UPPER 80S)
WITHIN THE RESIDUAL MOIST AIRMASS AND STEEP MID-LEVEL LAPSE RATES
(7.5-8 DEG C/KM) FROM AN EXPANSIVE EML MOVING INTO THE REGION FROM
THE FROM THE SOUTHERN PLAINS/MEXICO, WILL CREATE A VERY UNSTABLE
ENVIRONMENT, WITH MLCAPE OF 2500-3500 J/KG.
WHILE THE PRIMARY SEVERE THREAT IS EXPECTED TO LIE ACROSS EASTERN VA
AND NORTHEASTERN NC, IF CONVECTION MOVING OFF THE BLUE RIDGE
MOUNTAINS CAN DRIFT FAR ENOUGH SOUTH INTO THE NORTHERN PIEDMONT AND
NORTHERN COASTAL PLAIN COUNTIES DURING THE AFTERNOON AND EVENING,
THE FAT CAPE PROFILES COUPLED WITH DEEP LAYER SHEAR OF 30-35 KTS
COULD SUPPORT POTENTIALLY VIGOROUS UPDRAFTS AND SUPERCELLS CAPABLE
OF PRODUCING LARGE HAIL AND WIND DAMAGE. AN ISOLATED TORNADO IS ALSO
POSSIBLE.
TONIGHT:
THE SEVERE THREAT DIMINISHES AFTER SUNSET, THOUGH SOME ISOLATED TO
WIDELY SCATTERED CONVECTION MAY RE-DEVELOP OVERNIGHT. FOG POTENTIAL
TONIGHT APPEARS SIGNIFICANTLY LOWER THAN THE PREVIOUS 2 NIGHTS, BUT
MAY STILL OCCUR IN MORE ISOLATED/PATCHY VARIETY IN AREAS(NORTHEAST)
RECEIVING HEAVY RAIN. WARM OVERNIGHT LOWS 65-70 F.
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 TUESDAY/
AS OF 400 PM WEDNESDAY...
THE MID/UPPER LOW AND OCCLUDED SURFACE LOW WILL TRACK EAST ACROSS
SOUTHERN ONTARIO AND THE UPPER GREAT LAKES ON SATURDAY, DRAGGING A
COLD FRONT TO THE SOUTH THAT GUIDANCE IS IN GOOD AGREEMENT WILL PASS
THROUGH CENTRAL NC ON SATURDAY EVENING/NIGHT. INSTABILITY CONTINUES
TO LOOK MODERATE TO STRONG ALONG WITH 40+ KTS OF MID-LEVEL FLOW
(SIMILAR TO FRIDAY). HOWEVER, MOISTURE WITH THE FRONT DOES NOT LOOK
IMPRESSIVE, AS THE FLOW ALOFT IS STILL FROM A WESTERLY DIRECTION,
AND WE ONLY GET A GLANCING BLOW IN UPPER FORCING WITH THE LOW
TRACKING SO FAR TO OUR NORTH. ENSEMBLE MEAN QPF CONTINUES TO BE LESS
THAN A TENTH OF AN INCH. SO ONLY HAVE SLIGHT TO LOW CHANCE POPS IN
THE AFTERNOON AND EVENING, HIGHEST OVER THE NORTHERN PIEDMONT WHERE
AGAIN THE GREATEST UPPER FORCING WILL BE. STILL CAN'T RULE OUT A FEW
STRONG TO SEVERE STORMS. SATURDAY'S TEMPERATURES MAY BE KEPT DOWN A
BIT BY THE INCREASED PRECIPITATION CHANCES AND APPROACH OF THE COLD
FRONT, PARTICULARLY IN THE NW. BUT THEY SHOULD STILL BE QUITE WARM
WITH HIGHS IN THE MID-80S TO LOWER-90S. HEAT INDICES IN THE UPPER-
90S WILL AGAIN BE POSSIBLE IN THE SE.
OVERALL FORECAST CONFIDENCE DECREASES FOR THE REST OF THE PERIOD.
THE MID-LEVEL FLOW WILL TURN INCREASINGLY NW FROM SUNDAY INTO
TUESDAY, AS WE ARE CAUGHT BETWEEN THE LOW SLOWLY DRIFTING EAST OVER
NEW ENGLAND/SE CANADA AND RIDGING THAT STRENGTHENS AND BUILDS EAST
FROM THE PLAINS TO THE DEEP SOUTH AND TN VALLEY. AT THE SURFACE, A
SECONDARY BACKDOOR COLD FRONT LOOKS TO MOVE THROUGH CENTRAL NC
SOMETIME SUNDAY NIGHT OR MONDAY, AS THE GFS AND ECMWF START TO
DIVERGE ON HOW QUICKLY THE LOW OVER THE CANADIAN MARITIMES MOVES
EAST INTO THE ATLANTIC. THIS FRONT WILL BE QUASI-STATIONARY BUT
SHOULD REMAIN DRAPED TO OUR SOUTH AND WEST THROUGH TUESDAY, KEEPING
US RELATIVELY DRY AND STABLE. THE 12Z GFS AND ECMWF POTENTIAL FOR AN
MCS MOVING THROUGH IN THE NW FLOW ALOFT LATE MONDAY, BUT TIMING AND
PLACEMENT OF THESE SYSTEMS THIS FAR IN ADVANCE IS DIFFICULT TO
PINPOINT. SO ONLY HAVE SLIGHT CHANCE POPS IN THE SOUTH AND WEST FROM
SUNDAY THROUGH TUESDAY. GUIDANCE DEPICTS THE NEXT LOW MOVING NE FROM
THE CENTRAL PLAINS INTO THE UPPER GREAT LAKES ON TUESDAY AND
WEDNESDAY, WHICH MAY HELP PUSH THE BOUNDARY BACK NORTH AS A WARM
FRONT ON WEDNESDAY. BUT THERE IS STILL PLENTY OF DIVERGENCE IN
GUIDANCE ON THE LOW'S STRENGTH. REGARDLESS IT APPEARS SHOWER/STORM
CHANCES WILL INCREASE ON WEDNESDAY, SO HAVE CHANCE POPS RETURNING.
TEMPERATURE FORECAST CONFIDENCE IS LOW FROM SUNDAY ONWARD,
ESPECIALLY BY MIDWEEK, BUT THE OVERALL TREND SEEMS TO BE TRENDING A
BIT COOLER, ESPECIALLY ON THE ECMWF. AS COOL HIGH PRESSURE EXTENDS
SOUTH FROM THE HUDSON BAY INTO THE EASTERN US, EXPECT AT LEAST A
GRADUAL DROP IN TEMPERATURES, WITH HIGHS REACHING CLOSER TO NORMAL.
DEW POINTS SHOULD ALSO BECOME MORE COMFORTABLE, DROPPING INTO THE
50S.
AVIATION /18Z THURSDAY THROUGH TUESDAY/
AS OF 125 PM THURSDAY...
24 HOUR TAF PERIOD: ISOLATED TO WIDELY SCATTERED SHOWERS/STORMS
MOVING SEWD OUT OF CNTL VA ARE STILL POSSIBLE THIS AFT/EVE, MAINLY
NEAR KRWI (AND POSSIBLY NEAR KRDU AND KFAY), ACCOMPANIED BY THE
USUAL RESTRICTIONS/WINDS AND POSSIBLY SOME HAIL. OTHERWISE, VFR
CONDITIONS ARE EXPECTED TO PREVAIL THROUGH THE REST OF THE TAF
PERIOD. LATEST MODEL GUIDANCE INDICATES MINIMAL FOG POTENTIAL
TONIGHT/FRIDAY MORNING, HOWEVER THE THREAT IS NON-ZERO AT KRDU AND
KFAY DEPENDING WHERE THE SHOWERS/STORMS OCCUR.
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...LUCHETTI/CBL
SHORT TERM...LUCHETTI
LONG TERM...DANCO
AVIATION...KC/CBL
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