935
FXUS62 KRAH 301956
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
356 PM EDT MON JUN 30 2025
SYNOPSIS
SUB-TROPICAL HIGH PRESSURE CENTERED SOUTH OF BERMUDA WILL EXTEND
WESTWARD ACROSS THE SOUTH ATLANTIC STATES TODAY, THEN GRADUALLY LOSE
INFLUENCE AS A MID AND UPPER-LEVEL TROUGH AND SURFACE COLD FRONT
SETTLE INTO THE MIDDLE ATLANTIC AND CAROLINAS TUESDAY AND WEDNESDAY.
NEAR TERM /THROUGH TONIGHT/
AS OF 350 PM MONDAY...
THE PREVIOUS FORECAST AND RATIONALE REMAIN MOSTLY UNCHANGED. WHILE
SKIES WILL GENERALLY CLEAR WITH LOSS OF HEATING AND DIURNAL CUMULUS
AND CONVECTIVE DEBRIS CLOUD DISSIPATION, THERE IS A SIGNAL IN MODEL
GUIDANCE FOR THE DEVELOPMENT OF LOW STRATUS OVER THE SANDHILLS AND
SRN PIEDMONT TUE MORNING. A PERIOD OF PARTLY TO MOSTLY CLOUDY
CONDITIONS WILL CONSEQUENTLY BE POSSIBLE THEN AND THERE, WITH NEAR
PERSISTENCE LOW TEMPERATURES IN THE LWR-MID 70S.
PREV DISCUSSION
/ISSUED 1100 AM EDT MON JUN 30 2025/
A WEAKENING MID/UPR-LEVEL LOW OVER THE SOUTHEAST IN RECENT DAYS HAD
EDGED AS FAR NORTHEAST AS THE NRN GA/SC BORDER ON SUNDAY, WITH
ASSOCIATED CYCLONIC FLOW AND INFLUENCE EXTENDING ACROSS THE WRN HALF
OF NC. HOWEVER, WATER VAPOR SATELLITE DATA INDICATE THAT FEATURE HAS
SINCE DRIFTED SWWD TO THE S-CNTL GA/AL BORDER THIS MORNING, WHILE
CONTINUING TO WEAKEN. ANTICYCLONIC FLOW HAS CONSEQUENTLY BECOME
ESTABLISHED THROUGH THE MID/UPR-LEVELS THROUGHOUT CNTL NC, WHICH MAY
FURTHER DECREASE CONVECTIVE COVERAGE IN CNTL NC RELATIVE TO SUNDAY.
NONETHELESS, THE HEAT AND HUMIDITY WILL CONTRIBUTE TO ANOTHER DAY OF
MODERATE DESTABILIZATION AND LITTLE TO NO CINH, SO THERE WILL REMAIN
A 15-30 PERCENT CHANCE OF CONVECTION, PARTICULARLY WHERE A SURFACE
TROUGH WILL SUPPORT WEAK CONVERGENCE OVER THE WRN/SRN PIEDMONT AND
WRN SANDHILLS.
SHORT TERM /TUESDAY/
AS OF 340 PM MONDAY...
* CONTINUED HOT AND HUMID, WITH CONVECTION TO BECOME NUMEROUS OVER
THE SRN AND WRN PIEDMONT DURING THE AFTERNOON
THE WRN PERIPHERY OF A SUB-TROPICAL HIGH CENTERED NEAR AND SOUTH OF
BERMUDA WILL CONTINUE TO WEAKEN AND BREAK DOWN THROUGH TUE. IT WILL
DO SO OWING TO BOTH THE PASSAGE NEAR THE SOUTH ATLANTIC COAST OF A
MID/UPR-LEVEL LOW NOW NORTH OF GRAND BAHAMA AND ALSO WITH THE
APPROACH OF A POSITIVE TILT MID/UPR-LEVEL TROUGH THAT WILL PROGRESS
FROM ON TO THE CNTL PLAINS THIS AFTERNOON TO QC THROUGH THE MID MS
VALLEY BY 00Z WED. THE LATTER TROUGH WILL BE IMMEDIATELY PRECEDED BY
A CONVECTIVELY-AMPLIFIED ONE, AND MCVS FROM CLUSTERS OF PRE-FRONTAL
CONVECTION NOW STRETCHING FROM THE MIDDLE ATLANTIC TO THE SRN
PLAINS. WHILE A BROAD AREA OF WEAK, 10-20 METER MID-LEVEL HEIGHT
FALLS WILL RESULT OVER VA AND THE CAROLINAS, STRONGER, MESOSCALE
FORCING FOR ASCENT WILL BE MAXIMIZED ALONG THE TRACK OF ANY LOWER
PREDICTABILITY MCVS.
AT THE SURFACE, A PIEDMONT TROUGH WILL REMAIN OVER CNTL NC,
DOWNSTREAM OF AN OUTFLOW-REINFORCED AND MODULATED FRONT THAT WILL
APPROACH FROM THE NORTHWEST AND EXTEND FROM THE NRN MIDDLE ATLANTIC
COAST TO THE MID-SOUTH OR TN VALLEY BY 00Z WED.
DIURNAL CONVECTION WILL BECOME INCREASINGLY NUMEROUS OVER THE
PIEDMONT DURING THE AFTERNOON. SWLY LWR TO MID-TROPOSPHERIC FLOW
AROUND 20 KTS WILL SUPPORT MULTI-CELL DEVELOPMENT WITHIN A
MODERATELY UNSTABLE AND DEEPLY AND UNSEASONABLY MOIST ENVIRONMENT
CHARACTERIZED BY PWS OF NEAR 2", WITH AN ASSOCIATED THREAT OF STRONG
TO TREE-DAMAGING WET MICROBURSTS AND (ESPECIALLY) URBAN FLOODING.
HIGH TEMPERATURES WILL BE MOSTLY IN THE LWR 90S, WITH SOME UPR 80S
POSSIBLE OVER THE NW PIEDMONT WHERE CONVECTION AND OUTFLOW MAY
BECOME INCREASINGLY PREVALENT PRIOR TO PEAK DIURNAL HEATING.
LONG TERM /TUESDAY NIGHT THROUGH MONDAY/
AS OF 230 PM MONDAY...
* UNSEASONABLY WARM WEATHER CONTINUES INTO EARLY NEXT WEEK, WITH THE
EXCEPTION OF WEDNESDAY WHEN WIDESPREAD CLOUD COVER AND LINGERING
RAIN CHANCES WILL KEEP TEMPERATURES A FEW DEGREES BELOW NORMAL.
A PARENT SHORTWAVE WILL BE MOTORING THROUGH ONTARIO INTO THE
NEWFOUNDLAND AND LABRADOR PROVINCE BY TUES EVENING WITH THE BASE OF
THE TRAILING TROUGH AXIS OVER THE LOWER OHIO VALLEY EXPECTED TO
SWING ACROSS THE CAROLINAS THROUGH WED AFTERNOON. THIS FEATURE,
ALONG WITH ANY EMBEDDED MCV'S FROM PRIOR UPSTREAM CONVECTION, WILL
ACT AS THE PRIMARY FORCING MECHANISM FOR ONGOING SHOWERS/STORMS OVER
THE PIEDMONT OF NC EARLY TUES EVENING. THIS ACTIVITY IS EXPECTED TO
CONTINUE, ALTHOUGH GRADUALLY WEAKENING AND BECOMING MORE LOCALIZED,
AS IT SLOWLY SHIFTS EASTWARD THROUGH THE OVERNIGHT AND INTO WED.
MOST LOCATIONS ALONG AND WEST OF I-95 SHOULD SEE AT LEAST TRACE
AMOUNTS UP TO AROUND 0.5". NARROW SWATHS OF 1.5" TO 2.5" WILL BE
POSSIBLE AND MAY RESULT IN LOCALIZED AREAS OF FLASH FLOODING MAINLY
IN URBAN CORRIDORS. GIVEN THE LOW PREDICTABILITY OF THESE MCVS, AS
THEY DEPEND ENTIRELY ON THE INITIATION AND EVOLUTION OF CONVECTION
THAT HAS YET TO DEVELOP, CONFIDENCE ON MORE PRECISE LOCATIONS OF
HEAVIER RAINFALL REMAINS LOW AT THIS TIME.
A NARROW BAND OF UNSEASONABLY HIGH DEEP-LAYER MOISTURE EXTENDING
THROUGH THE MID-ATLANTIC INTO THE SOUTHEAST, WILL SLOWLY SAG
SOUTHEASTWARD IMMEDIATELY AHEAD OF THE TRAILING TROUGH AXIS AND
ASSOCIATED COLD FRONT REACH THE CAROLINA COAST BY LATE WED
AFTERNOON. CLOUD COVER AND PRECIPITATION CHANCES THROUGH PEAK
HEATING WILL LIKELY KEEP TEMPERATURES UP TO 5 DEGREES BELOW NORMAL,
MARKING THE COOLEST DAY IN THE TRIANGLE SINCE EARLY JUNE. DRIER AIR
THROUGH A DEEP LAYER WILL OVERSPREAD THE REGION AS SURFACE HIGH
PRESSURE SETTLES OVERHEAD THROUGH THE HOLIDAY WEEKEND. ONE CAVEAT IS
THAT AFOREMENTIONED COLD FRONT IS FORECAST ACROSS NORTHERN FL, AND
MODELS HAVE SIGNALED A CHANCE A LOW DEVELOPING ALONG THE FRONT.
MODELS HAVE BEEN SPLIT ON WHETHER THAT LOW WOULD DEVELOP OVER THE
NORTHEAST GULF OR OFF THE FLORIDA EAST COAST. NO LOCAL IMPACTS ARE
EVIDENT IN CURRENT MODEL GUIDANCE, BUT THERE COULD BE SOME
ENHANCEMENT OF POPS OVER THE EAST BY SUN INTO EARLY NEXT WEEK.
AVIATION /18Z MONDAY THROUGH SATURDAY/
AS OF 150 PM MONDAY...
WIDELY SCATTERED CONVECTION WILL CONTINUE TO BUBBLE IN THE VICINITY
OF A SURFACE TROUGH OVER THE PIEDMONT THROUGH EARLY TO MID-EVENING,
THEN DISSIPATE WITH LOSS OF HEATING/INSTABILITY. THERE IS A SIGNAL
IN MODEL GUIDANCE FOR THE DEVELOPMENT OF AN AREA OF IFR-MVFR
CEILINGS OVER THE SANDHILLS AND SRN PIEDMONT AND ADJACENT AREAS TUE
MORNING, CENTERED CLOSEST TO FAY AND WHERE A SHORT PERIOD OF FLIGHT
RESTRICTIONS ARE INDICATED IN THE 18Z TAFS. SOME OF THIS CLOUDINESS
MAY ALSO GLANCE PIEDMONT SITES AND REQUIRE INTRODUCTION IN THEIR
FORECASTS WITH LATER ISSUANCES.
OUTLOOK: THE CHANCE OF SHOWERS/STORMS WILL INCREASE WITH THE
APPROACH OF A MID/UPR-LEVEL TROUGH AND EMBEDDED DISTURBANCES TUE
AFTERNOON-NIGHT, PARTICULARLY ACROSS THE PIEDMONT. CHANCES FOR
CONVECTION, AND ALSO MORNING STRATUS AND FOG, WILL LINGER AT ERN
SITES WED-THU, WITH THE SLOW PASSAGE AND DISSIPATION OF A WEAK
FRONT.
RAH WATCHES/WARNINGS/ADVISORIES
NONE.
SYNOPSIS...MWS
NEAR TERM...MWS
SHORT TERM...MWS
LONG TERM...SWIGGETT/BLS
AVIATION...MWS
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