803
FXUS62 KRAH 041047
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
647 AM EDT FRI SEP 4 2026
WHAT HAS CHANGED
* STANLY CO. HAS BEEN ADDED TO THE HEAT ADVISORY FOR TODAY, WHICH
OTHERWISE REMAINS IN EFFECT FOR ALL BUT THE FAR NRN PIEDMONT
COUNTIES OF CNTL NC FROM 11 AM UNTIL 8 PM.
KEY MESSAGES
AS OF 350 AM FRIDAY...
1) A HEAT ADVISORY REMAINS IN EFFECT FOR ALL BUT THE FAR NRN
PIEDMONT COUNTIES OF CNTL NC FROM 11 AM UNTIL 8 PM. STANLY CO. WAS
ADDED TO THE ADVISORY WITH THIS FORECAST UPDATE.
2) SCATTERED STORMS, WITH A RISK OF DAMAGING, MULTI-CELL DOWNBURSTS,
WILL PROBABLY FOCUS ACROSS THE NRN/NE PIEDMONT AND NRN COASTAL PLAIN
THIS AFTERNOON-EVENING, THEN POSSIBLY THROUGHOUT CNTL NC ON SAT.
HOWEVER, INFLUENCES FROM LOWER PREDICTABILITY, EARLY DAY CONVECTION
SAT MAY HINDER STORM DEVELOPMENT OR RE-INTENSIFICATION OVER PARTS OF
CNTL NC LATER SAT AFTERNOON.
3) AFTER THE PASSAGE OF THE COLD FRONT SATURDAY NIGHT INTO SUNDAY,
COOLER AND DRIER AIR WILL FILTER INTO CENTRAL NC.
DISCUSSION
AS OF 350 AM FRIDAY...
KEY MESSAGE 1... STANLY CO. HAS BEEN ADDED TO THE HEAT ADVISORY FOR
TODAY, WHICH OTHERWISE REMAINS IN EFFECT FOR ALL BUT THE FAR NRN
PIEDMONT COUNTIES OF CNTL NC FROM 11 AM UNTIL 8 PM.
A LOWER MID-LATITUDE/SUB-TROPICAL RIDGE CENTERED OVER THE SRN
APPALACHIANS HAS WEAKENED A DECAMETER OR TWO SINCE PEAKING IN
STRENGTH A COUPLE OF DAYS AGO. IT NONETHELESS WILL REMAIN IN A
FAVORABLE LOCATION FOR EXCESSIVE HEAT IN CNTL NC TODAY, BEFORE
RETREATING SWWD AND YIELDING TO LOWERING HEIGHTS WITHIN A DEVELOPING
TROUGH ALONG AND JUST OFFSHORE THE EAST COAST THROUGH THE WEEKEND.
DESPITE THE GRADUALLY FALLING HEIGHTS ALOFT, THE ANTECEDENT AIRMASS
THAT DEVELOPED BENEATH AND DOWNSTREAM OF IT IN THE LOW-LEVELS WILL
REMAIN IN PLACE UNTIL ERADICATED AND/OR OTHERWISE COOLED BY A
FRONTAL PASSAGE OR WIDESPREAD CONVECTIVE OVERTURNING AND OUTFLOW. AS
SUCH, IT WILL REMAIN DANGEROUSLY HOT TODAY AND HAVE THE POTENTIAL TO
REMAIN SO THROUGH SAT, THOUGH BOTH CONVECTIVE DEBRIS CLOUDINESS AND
AFTERNOON CONVECTION MAY LIMIT THE MAGNITUDE OF SATURDAY'S HEAT.
TEMPERATURES TODAY SHOULD BE GENERALLY PERSISTENCE ONES, THOUGH
PERHAPS A DEGREE OR TWO LESS HOT AT RDU OWING TO THE 0.42" OF RAIN
THAT OCCURRED THERE FROM THE STORM THU EVENING (WHICH ALSO NOTABLY
PRODUCED A 45 KT WIND GUST). WHEN COMBINED WITH MIXED/AFTERNOON
DEWPOINTS IN THE UPR 60S OVER THE NW PIEDMONT TO LWR 70S
ELSEWHERE,HEAT INDEX VALUES WILL RANGE BETWEEN 100-105 F OVER THE NW
PIEDMONT TO MOSTLY 105-109 F IN THE ADVISORY AREA. A COUPLE OF
VALUES NEAR 110 F WILL BE POSSIBLE AT THE MOST RELIABLE OBSERVATION
SITES FROM THE NRN/ERN SANDHILLS TO THE CNTL COASTAL PLAIN (IE. NOT
IXA AND CTZ, WHERE VALUES NEAR 115 F WILL PROBABLY RESULT FROM
UNREPRESENTATIVE/HIGH-BIASED SURFACE DEWPOINTS AT THOSE SITES).
A CANOPY OF MID-LEVEL CONVECTIVE DEBRIS CLOUDINESS FROM THE
(PROBABLY WEAKENING) REMNANTS OF AN OVERNIGHT CONVECTIVE CLUSTER
FROM OH TO THE VIRGINIAS MAY LIMIT INSOLATION AND CURB THE HEAT OVER
ESPECIALLY THE NRN HALF OF CNTL NC ON SAT. AND IF THAT CONVECTIVE
CLUSTER WERE TO MAINTAIN INTENSITY MORE THAN CURRENTLY FORECAST,
WHICH THEY OFTENTIMES DO EAST OF THE APPALACHIANS, THEN A MORE-
PROMINENT COLD POOL/OUTFLOW AND POSSIBLE ONGOING CONVECTION WOULD
FURTHER LIMIT EARLY DAY HEATING THERE. THE AIRMASS WILL NONETHELESS
HAVE THE POTENTIAL TO BE AS HOT (OR NEARLY SO) AS PREVIOUS DAYS IN
THE ABSENCE OF THOSE LOWER PREDICTABILITY INFLUENCES FROM
CONVECTION/CLOUDS.
KEY MESSAGE 2... SCATTERED STORMS, WITH A RISK OF DAMAGING, MULTI-
CELL DOWNBURSTS, WILL PROBABLY FOCUS ACROSS THE NRN/NE PIEDMONT AND
NRN COASTAL PLAIN THIS AFTERNOON-EVENING, THEN POSSIBLY THROUGHOUT
CNTL NC ON SAT. HOWEVER, INFLUENCES FROM LOWER PREDICTABILITY, EARLY
DAY CONVECTION SAT MAY HINDER STORM DEVELOPMENT OR RE-
INTENSIFICATION OVER PARTS OF CNTL NC LATER SAT AFTERNOON.
NWLY FLOW AROUND THE AFOREMENTIONED RIDGE CENTERED OVER THE SRN
APPALACHIANS WILL GRADUALLY STRENGTHEN AND BE ACCOMPANIED BY WEAKLY
FALLING HEIGHTS AND COOLING THROUGH THE MID-LEVELS OVER THE SRN
MIDDLE ATLANTIC THROUGH SAT NIGHT, AS A CYCLONE PROGRESSES ACROSS
ATLANTIC CANADA.
MEANWHILE AT THE SURFACE, A LEE/PRE-FRONTAL TROUGH WILL REMAIN OVER
VA/NC, PRECEDING AN EFFECTIVE/OUTFLOW-REINFORCED FRONT AND TRAILING
SYNOPTIC ONE THAT WILL GRADUALLY SETTLE SWD ACROSS THE OH VALLEY AND
MIDDLE ATLANTIC. WHILE BOTH WILL PROBABLY REMAIN TO THE NORTH OF
CNTL NC UNTIL LATE SAT OR SAT NIGHT, OTHER AGGREGATE OUTFLOWS WILL
PROBABLY DEVELOP SWD ACROSS VA AND INTO THE NRN PIEDMONT AND NRN
COASTAL PLAIN OF NC THROUGH THIS EVENING. INDEED, SOME SUCH OUTFLOW
AND RELATED UNDULAR BORES ARE EVIDENT IN KAKQ DATA THIS MORNING
TRAILING THE MCS NOW MOVING OFFSHORE THE DELMARVA. THAT OUTFLOW WILL
PROBABLY CONTINUE TO SLOW, AS THE PARENT CONVECTION AND DIABATIC
COOLING EXIT OFFSHORE, AS IT PROGRESSES TOWARD THE FAR NE PIEDMONT
AND NRN COASTAL PLAIN THIS MORNING.
EACH OF THE THE SURFACE BOUNDARIES NOTED ABOVE WILL SERVE AS
POSSIBLE FOCI FOR RENEWED CONVECTIVE DEVELOPMENT WITH STRONG DAYTIME
HEATING. INITIALLY PULSE TO WEAKLY-ORGANIZED MULTI-CELLS ALONG THOSE
BOUNDARIES MAY CLUSTER ALONG COMMON OUTFLOW WHILE ORGANIZING AND
FORWARD PROPAGATING SEWD ACROSS THE NRN PIEDMONT AND NRN COASTAL
PLAIN OF NC THROUGH THIS EVENING, WITHIN A BELT OF 15-25 KTS OF MID-
LEVEL NORTHWESTERLIES. CONTINUED HIGH DCAPE OF 1000-1500 J/KG WILL
SUPPORT A RISK OF DAMAGING DOWNBURSTS.
WHILE THE ENVIRONMENT WILL SIMILARLY SHEARED AND SUPPORTIVE OF
DAMAGING DOWNBURSTS ON SAT, UNCERTAINTIES REGARDING THE DEGREE AND
LOCATION OF STRONGEST DESTABILIZATION CAST DOUBT ON WHERE THE
CONVECTIVE FOCUS AND SEVERE THREAT WILL EXIST ON SAT. ALTHOUGH THE
ENTIRE FORECAST AREA IS IN A SLIGHT, LEVEL 2 OF 5 RISK FOR SEVERE
STORMS, THIS POTENTIAL WILL PROBABLY BE GREATEST AWAY FROM OR ALONG
THE DIFFERENTIAL HEATING EDGES OF EARLY DAY CONVECTION AND DEBRIS
CLOUDINESS, WHICH AT THIS TIME WOULD FAVOR SRN ZONES FOR GREATEST
POTENTIAL.
KEY MESSAGE 3... AFTER THE PASSAGE OF THE COLD FRONT SATURDAY NIGHT
INTO SUNDAY, COOLER AND DRIER AIR WILL FILTER INTO CENTRAL NC.
THE COLD FRONT SHOULD BE SOUTH OF THE REGION BY SUNDAY MORNING,
WHICH WILL USHER IN COOLER AND DRIER AIR TO CENTRAL NC. HOWEVER,
MODEL GUIDANCE IS SUGGESTING THAT A SHORTWAVE TROUGH MAY MOVE
THROUGH THE REGION SOMETIME ON SUNDAY. THIS COULD ALLOW FOR POST-
FRONTAL RAIN TO LINGER THROUGH THE DAY ON SUNDAY. OVERALL LIGHT RAIN
IS EXPECTED AS MINIMAL INSTABILITY SHOULD BE IN PLACE IN THE POST
FRONTAL REGIME, HOWEVER A FEW RUMBLES OF THUNDER CANNOT BE RULED
OUT.
HIGH TEMPERATURES SHOULD RETURN TO THE 80S FROM SUNDAY THROUGH
TUESDAY, BEFORE POTENTIALLY RETURNING TO THE 90S BY MIDWEEK. THE
CHANCE OF RAIN DURING THIS PERIOD WILL BE GENERALLY LOW EACH DAY,
WITH AN ISOLATED DIURNAL THUNDERSTORM POSSIBLE EACH
AFTERNOON/EVENING ESPECIALLY LATE WEEK AS WARMING IS OCCURRING AND
MOISTURE IS RETURNING TO THE REGION. DETAILS ARE UNCLEAR ON A
POTENTIAL FRONTAL PASSAGE LATE WEEK.
AVIATION /11Z FRIDAY THROUGH TUESDAY/
AS OF 645 AM FRIDAY...
AREAS OF LOW STRATUS AND FOG OVER SERN NC THIS MORNING, INCLUDING
NEAR AND ESPECIALLY JUST SOUTHEAST OF FAY, SHOULD LIFT AND DISPERSE
TO VFR THROUGH ~14Z. SHOWERS AND STORMS WILL DEVELOP WITH DAYTIME
HEATING AND CLUSTER WHILE PROPAGATING SEWD ACROSS VA AND THE NRN
PIEDMONT AND NRN COASTAL PLAIN OF NC THROUGH THIS EVENING.
OUTLOOK: SCATTERED TO LOCALLY NUMEROUS CONVECTION WILL BE POSSIBLE
ALONG A PRE-FRONTAL TROUGH AND SUBSEQUENT OUTFLOW OVER CNTL NC ON
SAT, AS LIFT INCREASES WITH THE APPROACH AND PASSAGE OF A MID-LEVEL
DISTURBANCE. NELY FLOW BEHIND A BACKDOOR COLD FRONT MAY SUPPORT
AREAS OF IFR-MVFR CEILINGS SUN MORNING AND MON MORNING.
CLIMATE
RECORDS WITHIN REACH THIS FORECAST PERIOD:
RECORD HIGH TEMPERATURES:
SEPTEMBER 4: KRDU: 100/1925 KFAY: 100/1944
SEPTEMBER 5: KGSO: 97/1954 KRDU: 98/2023 KFAY: 99/1932
RECORD HIGH MINIMUM TEMPERATURES:
SEPTEMBER 4: KGSO: 72/2018 KRDU: 74/1921 KFAY: 75/2020
SEPTEMBER 5: KGSO: 73/2018 KRDU: 74/2012 KFAY: 74/1935
RAH WATCHES/WARNINGS/ADVISORIES
HEAT ADVISORY FROM 11 AM THIS MORNING TO 8 PM EDT THIS EVENING FOR
NCZ011-024>028-040>043-073>078-083>086-088-089.
AIR QUALITY ALERT FROM 10 AM THIS MORNING TO 8 PM EDT THIS EVENING
FOR NCZ021>023-038-039.
DISCUSSION...MWS/LBH
AVIATION...MWS
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