314
FXUS62 KRAH 052159
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
559 PM EDT SUN JUL 5 2026
WHAT HAS CHANGED
* HEAT ADVISORY CANCELLED DUE TO WIDESPREAD RAIN-COOLED AIR FROM
SHOWERS AND THUNDERSTORMS, WITH ASSOCIATED MARKED DECREASE IN
TEMPERATURES AND HEAT INDEX VALUES
* CONVECTIVE CHANCES RAISED FOR TODAY AHEAD OF A MID-LEVEL
DISTURBANCE (MCV) APPROACHING FROM THE NRN MIDLANDS OF SC AND
CHARLOTTE METRO VICINITY
* HOTTEST CONDITIONS OCCURRED FRI-SAT AND WILL UNDOUBTEDLY BE
TRENDING LESS SO IN THE COMING DAYS
KEY MESSAGES
AS OF 225 PM SUNDAY...
1) CONTINUED HOT, THOUGH TRENDING LESS SO, WITH SCATTERED TO
LOCALLY NUMEROUS CONVECTION THIS AFTERNOON-EVENING AND WITH AT LEAST
A FEW STRONG TO DAMAGING DOWNBURSTS PROBABLE
2) CHANCES FOR DIURNALLY DRIVEN CONVECTION EACH DAY THROUGH THE WEEK
AND INTO THE WEEKEND.
DISCUSSION
AS OF 225 PM SUNDAY...
KEY MESSAGE 1...CONTINUED HOT, THOUGH TRENDING LESS SO, WITH
SCATTERED TO LOCALLY NUMEROUS CONVECTION THIS AFTERNOON-EVENING AND
WITH AT LEAST A FEW STRONG TO DAMAGING DOWNBURSTS PROBABLE
IN THE MID/UPR-LEVELS, THE PREVIOUSLY, ANOMALOUSLY STRONG LWR MID-
LATITUDE ANTICYCLONE RESPONSIBLE FOR THIS NOW WANING HEAT WAVE HAS
WEAKENED 5-6 DECAMETERS SINCE IT PEAKED OVER THE VIRGINIAS AT 00Z-
12Z FRI; AND IT HAS ALSO DRIFTED WELL OFFSHORE AND EAST OF CNTL NC,
NOW ABOUT MIDWAY OF BERMUDA AND THE COAST OF THE CAROLINAS. MID-
LEVEL FLOW BEHIND THE DEPARTING ANTICYCLONE AND DOWNSTREAM OF A
SHORTWAVE TROUGH OVER THE MID MS VALLEY HAS TO VEERED TO SWLY/WLY
OVER CNTL NC PER 12Z UPR AIR AND MORE RECENT REGIONAL VWP DATA. A
MID-LEVEL TROUGH, CONVECTIVELY-AMPLIFIED FROM CONVECTION OVER THE TN
VALLEY AND SRN APPALACHIANS ON SAT, HAS BEEN EVIDENT IN 700 MB
CHARTS AND VISIBLE SATELLITE DATA THIS MORNING OVER THE UPSTATE AND
NOW MIDLANDS OF SC. THIS FEATURE WILL TRACK THROUGH THE SWLY/WLY
FLOW REGIME AND PROBABLY FOCUS ASCENT OVER THE NC PIEDMONT THIS
AFTERNOON, AMID MORE-BROADLY AND WEAKLY FALLING HEIGHTS THAT HAVE
BEEN EVIDENT THROUGH MOST OF THE MIDDLE ATLANTIC AND SOUTHEAST FOR
THE PAST COUPLE OF DAYS. ANOTHER, HIGHER-LEVEL AND MORE-SUBTLE
PERTURBATION EVIDENT IN WATER VAPOR SATELLITE DATA NEAR THE ATLANTA
METRO IS FORECAST TO DEAMPLIFY AS IT TRACKS INTO THE UPSTATE OF SC
THIS EVENING AND ACROSS CNTL NC TONIGHT-EARLY MONDAY.
AT THE SURFACE, THE PATTERN REMAINS VERY SIMILAR TO SAT IN AND
AROUND CNTL NC, WITH AN APPALACHIAN-LEE TROUGH EXTENDING ACROSS THE
SRN MIDDLE ATLANTIC PIEDMONT AND HIGH PRESSURE STRETCHING ACROSS THE
APPALACHIAN PLATEAU AND LWR OH VALLEY. A WEAK LEE LOW MAY FORM
WITHIN THE LEE TROUGH OVER VA, WHILE A WAVY FRONTAL ZONE, STRETCHING
FROM SRN NEW ENGLAND WWD AND ACROSS NRN PA AND TO A 1013 MB,
CONVECTIVELY-AMPLIFIED LOW OVER NRN OH, MAY BECOME AUGMENTED BY
OUTFLOW SWD ACROSS PA BUT OTHERWISE MOVE LITTLE THROUGH TONIGHT. IT
WILL THEN PROBABLY BE DRAWN SWD INTO THE LEE LOW AND ASSOCIATED
CONVERGENCE OVER VA LATER MON AND MON NIGHT.
CUMULUS DOWNSTREAM OF THE AFOREMENTIONED MID-LEVEL TROUGH HAS
ALREADY DEVELOPED AND DEEPENED CONSIDERABLY OVER THE SANDHILLS AND
ADJACENT PORTIONS OF THE PIEDMONT OF THE CAROLINAS SINCE 15Z, WITH
LOCALLY NUMEROUS CELLS NEAR AND NORTHEAST OF CAE. THESE SHOWERS AND
STORMS WILL LIKELY CONTINUE TO GROW IN COVERAGE AND INTENSITY EARLY
THIS AFTERNOON WHILE SPREADING GENERALLY ENEWD ACROSS THE PIEDMONT
AND SANDHILLS. CONTINUED HIGH DCAPE, WITH OBSERVED VALUES BETWEEN
1000-1200 J/KG AT GSO AND MHX THIS MORNING AND CORROBORATED BY
VALUES A COUPLE OF HUNDRED J/KG HIGHER DOWNSTREAM OF THE DEVELOPING
CONVECTION IN MORE RECENT SPC MESO/OBJECTIVE ANALYSIS DATA, WILL
PROVIDE A FAVORABLE ENVIRONMENT FOR DAMAGING DOWNBURSTS.
BY MOST-TYPICALLY-USED MEASURES OF HIGH TEMPERATURE FORECASTING (EG.
TEMPERATURES AT 850 AND 925 MB AND 1000-850 MB THICKNESS), THE
AIRMASS OVER NC HAS ALREADY COOLED RELATIVE TO PREVIOUS DAYS.
INDEED, 24-HOUR SURFACE TEMPERATURE CHANGES TODAY HAVE BEEN MINUS 2-
5 F THROUGH THE MORNING. DIABATIC COOLING FROM CONVECTION AND
OUTFLOW THIS AFTERNOON WILL FURTHER COOL THE AIRMASS IN PLACE. HEAT
INDEX VALUES FROM THE MOST ACCURATE/RELIABLE SOURCES (IE. ASOS THAT
DIRECTLY MEASURE SURFACE DEWPOINT VS AWOS, ECONET, AND RAWS
INSTRUMENTATION THAT INDIRECTLY DERIVE DEWPOINT BY MEASURING
TEMPERATURE AND RH) WILL NONETHELESS STILL LIKELY REACH THE 102-106
F RANGE THROUGH THE ADVISORY AREA. FOR AS HOT AS THE AMBIENT
TEMPERATURES HAVE BEEN DURING THIS HEAT WAVE, THE HIGHEST HEAT INDEX
MEASURED BY ANY ASOS IN CNTL NC HAS BEEN 108 F (RDU).
TEMPERATURES WILL BE LESS HOT YET ON MON OWING TO COOLING FROM TODAY
AND ADDITIONAL, SCATTERED TO LOCALLY NUMEROUS CONVECTION AND
OVERTURNING ON MON, AMID CONTINUED, SWLY AND CONVECTIVELY-PERTURBED
MID-LEVEL FLOW. SLIGHTLY LESS HOT TEMPERATURES MAY BE OFFSET BY
SLIGHTLY HIGHER SURFACE DEWPOINTS, SO HEAT INDEX VALUES WILL STILL
REACH THE UPR 90S TO NEAR 105 - MOSTLY BELOW HEAT ADVISORY CRITERIA
OF 105 F. DCAPE IS FORECAST TO BE MUCH LESS ON MON THAN RECENT DAYS,
WHICH SUGGESTS DOWNBURST POTENTIAL WILL BE LESS AFTER PEAKING TODAY.
KEY MESSAGE 2... CHANCES FOR DIURNALLY DRIVEN CONVECTION EACH DAY
THROUGH THE WEEK AND INTO THE WEEKEND.
CENTRAL NC WILL BE ON THE NW PERIPHERY OF THE MID-LEVEL ANTICYCLONE
OFF THE SOUTHEAST US COAST, WITH A S/W TROUGH TO THE WEST OVER THE
MID-MS VALLEY TUE AND WED. THE S/W WILL WEAKEN AS IT SLOWLY SHIFTS
EWD ACROSS THE TN/OH-VALLEY WED NIGHT/THU, THEN CONTINUE ACROSS THE
CAROLINAS/MID-ATLANTIC THU NIGHT/FRI. ANOTHER TROUGH MAY AMPLIFY
OVER THE OH VALLEY AS A S/W APPROACHES FROM THE WEST LATE WEEK,
DRIFTING SLOWLY EWD OVER THE WEEKEND. AT THE SURFACE, A FRONT MAY
MOVE INTO THE AREA TUE/TUE NIGHT AS THE PARENT LOW SHIFTS OFF THE
NORTHEAST US COAST, WITH A SECONDARY AREA OF LOW PRESSURE LINGERING
OVER THE AREA WED/WED NIGHT ALONG THE OLD BOUNDARY. GENERAL PIEDMONT
TROUGHING EXPECTED THROUGH AT LEAST THU AND FRI, WITH MODEL SPREAD
INCREASING THEREAFTER. PWATS OF 1.8 TO 2.1 INCHES ARE EXPECTED
THROUGH THE WEEK, WITH SBCAPE OF ROUGHLY 1000-2000 J/KG AND BULK
SHEAR OF 20-30 KTS (VIA GFS FORECAST SOUNDINGS). GIVEN THE CONTINUED
MOIST, UNSTABLE ENVIRONMENT, EXPECT DIURNALLY DRIVEN SHOWERS AND
STORMS EACH DAY, WITH A FOCUS ALONG SURFACE BOUNDARIES. WITH LITTLE
APPRECIABLE AIRMASS CHANGE, TEMPERATURES WILL GENERALLY REMAIN ABOVE
NORMAL, WITH FRIDAY EXPECTED TO BE THE WARMEST DAY AND WEDNESDAY
PERHAPS THE RELATIVE COOLEST.
AVIATION /18Z SUNDAY THROUGH FRIDAY/
AS OF 115 PM SUNDAY...
CONVECTION WITH STRONG WIND GUSTS WILL CONTINUE TO GROW
IN COVERAGE, TO SCATTERED TO LOCALLY NUMEROUS, AND INTENSITY AHEAD
OF A MID-LEVEL TROUGH NOW PROGRESSING ACROSS THE NC PIEDMONT AND
SANDHILLS. PROB30 AND/OR TEMPO THUNDER WILL COVER SUCH OCCURRENCES,
MOST LIKELY AT PIEDMONT SITES AND FAY. LIGHT SSWLY SURFACE WINDS AND
VFR CONDITIONS ARE OTHERWISE EXPECTED EXCEPT FOR A SMALL RISK OF
STRATUS AND MIST/FOG MAINLY AT RWI MON MORNING.
OUTLOOK: SCATTERED TO LOCALLY NUMEROUS CONVECTION WILL PROBABLY
RESULT AGAIN EACH AFTERNOON THROUGH MID-WEEK, AS A SERIES OF MID-
LEVEL DISTURBANCES OVERSPREAD A PERSISTENT, APPALACHIAN-LEE/PIEDMONT
SURFACE TROUGH AND EVENTUALLY A BACKDOOR COLD FRONT LIKELY TO SETTLE
INTO THE AREA BY WED. MORNING STRATUS/MIST MAY ALSO RESULT IN AREAS
THAT RECEIVE CONVECTIVE RAIN THE PREVIOUS AFTERNOON-EVENING.
CLIMATE
RECORDS WITHIN REACH THIS FORECAST PERIOD...
RECORD HIGH TEMPERATURES:
JULY 6: KFAY: 100/2024
JULY 10:KRDU: 99/1993
RECORD HIGH MINIMUM TEMPERATURES:
JULY 6: KGSO: 76/1999 KRDU: 79/1900 KFAY: 77/2024
JULY 7: KGSO: 73/2024 KRDU: 77/1900 KFAY: 78/2017
RAH WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION...MWS/KCP
AVIATION...MWS
CLIMATE...RAH
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