118
FXUS62 KRAH 161912
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
312 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 1130 AM FRIDAY...
THE PREVIOUS FORECAST REMAINS IN GOOD SHAPE, ONLY ADJUSTING POPS
SLIGHTLY ALONG THE NORTHERN PIEDMONT AND COASTAL PLAIN AS NEWER HI-
RES MODEL DATA COMES IN. COMPARING THE 06Z TO THE 12Z NCAR HRR
NEURAL NETWORK OUTPUT MODEL SHOW THE PROBABILITIES FOR SEVERE WINDS
AND HAIL THIS AFTERNOON AND OVERNIGHT HAVE SHIFTED SLIGHTLY
NORTHWARD. THE GENERAL HI-RES MODEL GUIDANCE STILL HAS A LARGE
SPREAD FOR BOTH ROUNDS THIS AFTERNOON AND OVERNIGHT. EXPECTING THE
MCSS OVER THE KENTUCKY REGION THIS MORNING TO CROSS THE APPALACHIAN
MOUNTAINS AND AND KEEP ITS ENERGY AND MOMENTUM ALONG THE NC/VA
BORDER THIS AFTERNOON. WITH ALL THE SAID, I EXPECT THE SLIGHT RISK
IN VA TO BE EXPANDED SOUTH INTO PORTION OF NORTHERN NC WITH SPCS
MORNING UPDATE.
* THERE REMAINS A CONDITIONAL RISK FOR STRONG/SEVERE STORMS ACROSS
THE NORTHERN PIEDMONT AND NORTHERN COASTAL PLAIN THIS
AFTERNOON/EARLY EVENING
PREVIOUS DISCUSSION:
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 310 PM FRIDAY...
* THERE IS STILL A FAIR BIT OF UNCERTAINTY, HOWEVER A CONDITIONAL
THREAT FOR ISOLATED STRONG STORMS SAT AFT/EVE REMAINS.
ALOFT, THE SUB-TROPICAL RIDGE WILL REMAIN SUPPRESSED WELL SOUTH OF
THE AREA AS A CLOSED LOW TRACKS EWD ACROSS THE SRN/ERN GREAT LAKES
AND NORTHEAST US SAT/SAT NIGHT. A COUPLE OF SHORTWAVE DISTURBANCES
WITHIN THE ATTENDANT TROUGH WILL MOVE ACROSS THE REGION ON SAT
BEFORE THE TROUGH SHIFTS EWD OUT OF THE AREA SAT NIGHT. AT THE
SURFACE, THE PARENT LOW WILL OCCLUDE OVER THE GREAT LAKES ON SAT,
WHILE A SECONDARY LOW DEVELOPS OVER THE NORTHEAST US. THE ATTENDANT
COLD FRONT SHOULD PROGRESS EWD ACROSS THE AREA SAT AFT/EVE AS THE
SECONDARY LOW LIFTS NEWD ALONG THE NEW ENGLAND COAST.
UNCERTAINTY: THE BIGGEST UNCERTAINTY CONTINUES TO BE WHETHER THE
CONVECTION EXPECTED TO MOVE ACROSS THE MID-MS AND TN VALLEY REGIONS
TONIGHT, WILL HOLD TOGETHER AND MOVE INTO THE AREA EARLY SAT. AND IF
IT DOES MOVE INTO THE AREA, HOW LONG IT WILL HOLD TOGETHER. THEN,
HOW MUCH THE SHOWERS AND ASSOCIATED CLOUD COVER WILL STABILIZE THE
ATMOSPHERE AND/OR LIMIT DESTABILIZATION DURING THE AFT/EVE, THUS
IMPACTING WHETHER SHOWERS WILL RE-DEVELOP ALONG THE FRONT AND MOVE
ACROSS THE AREA SAT EVE/NIGHT. LATEST HI-RES GUIDANCE CONSENSUS HAS
THE SHOWERS/ISO STORMS HOLDING TOGETHER AND MOVING INTO THE WESTERN
PIEDMONT AROUND DAYBREAK SAT, THEN WEAKENING AND/OR DISSIPATING
SOMEWHERE OVER CENTRAL NC SAT MORN.
CONVECTION: FORECAST SOUNDINGS OFF THE NAM SHOW DESTABILIZATION
ACROSS MUCH OF THE AREA (ALBEIT BRIEFLY IN THE NW), WITH HIGHEST
CAPE VALUES ACROSS THE SANDHILLS AND COASTAL PLAIN DURING THE
AFT/EVE. MAX MUCAPE AROUND 2000 J/KG WITH EFFECTIVE SHEAR AROUND 40
KTS AT KFAY AND KRWI (AND BRIEFLY AT KRDU). ADDITIONALLY, WITH 25-35
KTS AT THE TOP OF THE MIXED LAYER, WIND GUSTS IN THAT RANGE WILL BE
POSSIBLE UNTIL THE NOCTURNAL INVERSION SETS UP SAT EVE. ADDITIONAL
SHOWERS/STORMS COULD DEVELOP DURING THE AFT/EVE ALONG/AHEAD OF THE
FRONT IF ENOUGH DESTABILIZATION IS REALIZED, AND COULD RESULT IN
STRONG WIND GUSTS AND POSSIBLY SOME HAIL. HOWEVER, THERE IS STILL
SOMEWHAT LOW CONFIDENCE IN TIMING, LOCATION, AND COVERAGE OF THAT
THREAT, IF IT MATERIALIZES.
TEMPERATURES: ALSO DEPENDENT ON WHAT HAPPENS WITH THE EARLY
CONVECTION SAT MORN, BUT FOR NOW EXPECT HIGHS RANGING FROM MID 80S
NW TO LOW 90S SE. BASED ON CURRENT TIMING OF THE FRONT, EXPECT LOWS
TO RANGE FROM LOW 60S NW TO UPPER 60S SE.
LONG TERM /SUNDAY THROUGH FRIDAY/
AS OF 205 PM FRIDAY...
* LARGELY UNSETTLED WEATHER IS EXPECTED FOR THE BEGINNING OF THE
EXTENDED PERIOD, UNTIL A COLD FRONT MOVES THROUGH THE REGION
WEDNESDAY OR THURSDAY.
* TEMPERATURES WILL REMAIN ABOVE AVERAGE UNTIL WEDNESDAY, WITH BELOW
AVERAGE TEMPERATURES EXPECTED THURSDAY AND FRIDAY.
SUNDAY AND MONDAY, A FRONT IS EXPECTED TO BE QUASI-STATIONARY TO OUR
SOUTH. THESE DAYS ARE EXPECTED TO BE MOSTLY DRY, HOWEVER AFTERNOON
SHOWERS MAY DEVELOP IN THE SOUTH DEPENDING ON HOW FAR NORTH THE
FRONT STALLS. OTHERWISE, TEMPERATURES SHOULD BE AROUND 5 DEGREES
ABOVE AVERAGE, WITH MAXIMUM TEMPERATURES ON BOTH DAYS IN THE LOW 80S
IN THE NORTH, TO THE UPPER 80S, MAYBE REACHING LOW 90S IN THE SOUTH.
SUNDAY AND MONDAY NIGHT SHOULD ALSO HAVE LOWS IN THE 60S.
RAIN CHANCES INCREASE AGAIN TUESDAY AFTERNOON AS LOW PRESSURE
ASSOCIATED WITH THE PREVIOUSLY STALLED FRONT PROGRESSES NORTH OF THE
REGION THROUGH THE MID ATLANTIC. THERE IS LARGE MODEL SPREAD ON THE
STRENGTH, TIMING, AND LOCATION OF THIS SYSTEM, HOWEVER MODELS ARE
GENERALLY SHOWING A WARM FRONT MOVING NORTH THROUGH THE REGION ON
TUESDAY, INCREASING RAIN CHANCES, AND A COLD FRONT MOVING THROUGH
THE REGION WEDNESDAY AFTERNOON OR THURSDAY MORNING. THUS, THERE ARE
RAIN CHANCES TUESDAY AND WEDNESDAY, WHICH COULD POTENTIALLY LINGER
INTO THURSDAY. THE BEST CHANCE FOR WIDESPREAD RAIN CURRENTLY LOOKS
TO BE WEDNESDAY AFTERNOON.
TEMPERATURES SHOULD FALL BEHIND THE FRONT, LEAVING MAXIMUM
TEMPERATURES IN THE 70S ON THURSDAY. HIGH PRESSURE SHOULD BUILD IN
BEHIND THE COLD FROPA, LEAVING FRIDAY DRY AND KEEPING MAXIMUM
TEMPERATURES IN THE 70S.
AVIATION /18Z FRIDAY THROUGH WEDNESDAY/
AS OF 215 PM FRIDAY...
FORECAST CONFIDENCE IS LOWER THAN NORMAL WRT TO STORM POTENTIAL THIS
AFTERNOON AND EVENING.
UPPER LEVEL RIDGE ARCHING OVER THE MID-ATLANTIC REGION SUPPORTING AN
INCREASE IN CLOUD COVERAGE AND ISOLATED STORMS THIS AFTERNOON AND
EVENING. A FEW ISOLATED SEVERE STORMS COULD BRING FLIGHT
RESTRICTIONS TO ANY OF THE NORTHERN TAF SITES THIS AFTERNOON AND
EVENING. STRONG WIND GUSTS WILL BE THE MAIN HAZARD WITH THESE STORMS
SO ALONG WITH TSRA IN THE TAF, ADDED GUSTS UP TO 45KTS IN THE PROB30
GROUPS. AS THE LOW LEVEL JET MOVES THROUGH AFTER THE INITIAL ROUND
OF EXPECTED STORMS, LLWS WILL BE THE NEXT AVIATION HAZARD LATE
OVERNIGHT INTO EARLY SATURDAY MORNING. AS THE UPPER LEVEL TROUGH
MOVES OFFSHORE, A COLD FRONT WILL BRING ANOTHER ROUND OF FLIGHT
RESTRICTIONS SATURDAY MORNING. THE MODELS HAVE BEEN BACK AND FORTH
ON WHETHER OR NOT THE LINE OF STORMS MAKES ITS TO THE REGION,
THEREFORE AROUND LINE OF PROB30S FOR ALL TAF SITES BETWEEN 09Z AND
13Z FOR A CHANCE OF THUNDERSTORMS WITH FLIGHT RESTRICTIONS.
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...CA/CBL
SHORT TERM...KC
LONG TERM...HELOCK
AVIATION...CA/CBL
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