581
FXUS62 KRAH 182316
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
715 PM EDT SAT JUL 18 2026
WHAT HAS CHANGED
* HEAVY RAINFALL THREAT APPEARS PROBABLE SUNDAY NIGHT INTO
MONDAY
KEY MESSAGES
AS OF 112 PM SATURDAY...
1) HEAT ADVISORY REMAINS IN EFFECT UNTIL 9 PM FOR ALL BUT THE NW
PIEDMONT. AN ADVISORY MAY BE NEEDED FOR PORTIONS OF THE AREA SUNDAY.
2) MARGINAL TO SLIGHT RISK OF SEVERE STORMS THIS AFTERNOON AND
EVENING AND SUNDAY. A HEAVY RAINFALL THREAT IS ALSO POSSIBLE SUNDAY.
3) SEASONABLY HOT AND HUMID SUMMER PATTERN WITH UNSETTLED WEATHER
CONTINUING THROUGH MIDWEEK.
DISCUSSION
AS OF 112 PM SATURDAY...
KEY MESSAGE 1... HEAT ADVISORY REMAINS IN EFFECT UNTIL 9 PM FOR ALL
BUT THE NW PIEDMONT. AN ADVISORY MAY BE NEEDED FOR PORTIONS OF THE
AREA SUNDAY.
A HEAT ADVISORY REMAINS IN EFFECT UNTIL 9 PM FOR ALL BUT THE
NORTHWEST PIEDMONT. HEAT INDICES WILL REMAIN HIGH THIS AFTERNOON AND
EARLY EVENING, UPWARDS OF 100 TO 104 ACROSS THE TRIAD AND NORTHWEST,
TO 105 TO 109 ELSEWHERE. A FEW LOCATIONS IN THE ADVISORY AREA MAY
REACH A HEAT INDEX OF 110, CLOSE TO AN EXTREME HEAT WARNING. BUT
GIVEN THE LIMITED SCOPE OF THIS, DECIDED TO JUST THE ADVISORY. WE
ALSO CONTEMPLATED ADDING THE TRIAD TO THE HEAT ADVISORY, WITH
DEWPOINTS STILL IN THE LOW 70S. HOWEVER, FEEL MIXING SHOULD KEEP
HEAT INDICES AT OR JUST BELOW CRITERIA.
THE HEAT ADVISORY MAY BE ALLOWED TO EXPIRE PRIOR TO 9 PM, ESPECIALLY
WITH THE APPROACH OF ISOLATED TO SCATTERED STORMS THIS AFTERNOON AND
EVENING. A HEAT ADVISORY MAY LIKELY BE NEEDED FOR A SIMILAR REGION
OF THE TRIANGLE, SANDHILLS AND SOUTHERN TO CENTRAL COASTAL PLAIN,
WITH PROJECTED HEAT INDICES OF 102 TO 107 DEGREES PRIOR TO STORM
DEVELOPMENT.
KEY MESSAGE 2... MARGINAL TO SLIGHT RISK OF SEVERE STORMS THIS
AFTERNOON AND EVENING AND SUNDAY. A HEAVY RAINFALL THREAT IS ALSO
POSSIBLE SUNDAY.
WE CONTINUE TO MONITOR THE THREAT OF ISOLATED TO SCATTERED SHOWERS
AND STORMS TODAY AND SUNDAY. THE MORNING AND EARLY AFTERNOON SURFACE
ANALYSIS REVEALED A CLEAR LEE TROUGH OVER WESTERN NC, WITH A WARM
FRONT WELL TO THE NORTH IN MD AND WESTERN PA, AND A COLD FRONT OVER
THE MID MS VALLEY INTO THE GREAT LAKES. CONVECTIVE COVERAGE THIS
AFTERNOON AND EVENING LOOKS TIED MAINLY TO THE LEE TROUGH. AGITATED
CUMULUS, HOWEVER, HAS LED TO EARLY DEVELOPMENT OVER THE CENTRAL AND
NORTHEAST PIEDMONT, WEST OF RDU. THIS ACTIVITY SHOULD REMAIN
ISOLATED AS IT TRACKS OVER PORTIONS OF THE TRIANGLE AND NORTHEAST
PIEDMONT THROUGH THE AFTERNOON. THE HREF/REFS AND RECENT HRRR/NEST
SHOW A MORE CONCENTRATED SW TO NE LINE OF SCATTERED CONVECTION ALONG
THE LEE TROUGH IN WESTERN NC THAT POTENTIALLY IMPACTS THE TRIAD,
TRIANGLE, PIEDMONT AND PORTIONS OF THE COASTAL PLAIN EARLY TO LATE
EVENING AS IT SLOWLY TRACKS ESE AHEAD OF SOUTHWARD MOVING COLD
FRONT. WHILE CONFIDENCE ON COVERAGE IS SOMEWHAT LOW, STORMS THAT DO
DEVELOP WILL CARRY THE THREAT OF DAMAGING WIND GUSTS, OWING TO DCAPE
BETWEEN 1200-1400 J/KG, MLCAPE OF 1500-2500 J/KG, AND SHEAR UP TO 25
KT. THE MAIN SEVERE RISK LOOKS TO BE BETWEEN 2 AND 10 PM.
ON SUNDAY, THE FRONTAL BOUNDARY LOOKS TO BE STARTING OUT IN THE
LOWER OH VALLEY AND VA, SLOWLY SAGGING SOUTH INTO THE REGION SUNDAY
NIGHT TO EARLY MONDAY. A LEE TROUGH WILL STILL REMAIN PRESENT. BOTH
OF THESE SURFACE FEATURES SHOULD AID MORE COVERAGE OF STORMS, AND
CAMS SUGGEST AN EARLIER INITIATION IN THE EARLY AFTERNOON, PEAKING IN
THE EVENING, BUT PERHAPS LINGERING INTO PORTIONS OF THE OVERNIGHT
HOURS AS THE BOUNDARY SETTLES ALONG/NEAR THE US-64 CORRIDOR. SIMILAR
TO TODAY, STORMS WILL BE CAPABLE OF DAMAGING WINDS GIVEN SLIGHTLY
HIGHER SHEAR AND SIMILAR THERMODYNAMICS. A HEAVY RAINFALL THREAT IS
ALSO POSSIBLE GIVEN HIGH PW'S AROUND 2 INCHES AND FLOW NEARLY
PARALLEL TO THE BOUNDARY.
KEY MESSAGE 3... SEASONABLY HOT AND HUMID SUMMER PATTERN WITH
UNSETTLED WEATHER CONTINUING THROUGH MIDWEEK.
A STALLED BOUNDARY ASSOCIATED WITH ACTIVE WEATHER SUNDAY INTO SUNDAY
NIGHT WILL GRADUALLY WASHOUT AND GIVE WAY TO SOUTHWESTERLY FLOW
EARLY NEXT WEEK, WITH CENTRAL NC REMAINING ON THE WARM AND UNSTABLE
SIDE OF THE SYNOPTIC FRONTAL ZONE. RELATIVELY LOWER HEIGHTS ALOFT
ASSOCIATED WITH THE BROAD CYCLONIC FLOW OVER THE GREAT LAKES AND
NORTHEAST, ALONG WITH A WEAKNESS IN THE SUBTROPICAL RIDGE OVER THE
NORTHEAST GULF, SHOULD SUPPORT CONTINUED PERIODS OF MAINLY
AFTERNOON/EVENING SHOWERS AND STORMS MONDAY AND TUESDAY, BEFORE A
STRONGER SYNOPTIC COLD FRONT ATTENDANT TO A DEEPER UPPER TROUGH IS
PROGGED TO PUSH THROUGH THE REGION. A BETTER SEVERE THREAT MAY
UNFOLD WEDNESDAY WITH THE FRONT AND WHAT SHOULD BE RATHER STRONG MID-
LEVEL FLOW IN THE BASE OF THE TROUGH, ALTHOUGH THE OVERALL PATTERN
OF MULTI-DAY SHOWERS/STORMS AND OVERTURNING LENDS SOME UNCERTAINTY
TO THE THREAT.
ADDITIONAL RAINFALL AMOUNTS OF 1-2 INCHES SEEM REASONABLE MON-WED AS
PW REMAINS ANOMALOUSLY HIGH ACROSS THE SOUTHEAST, DUE IN PART TO THE
A WEAK SURFACE TROUGH OR LOW THAT MODELS HAVE BEEN INDICATING WILL
DEVELOP OVER THE NORTHEAST GULF BY SUNDAY. HIGHER RAINFALL AMOUNTS
WILL DEPEND ON WHERE SHOWERS AND STORMS ARE MORE ROBUST, WITH MODELS
GENERALLY FAVORING EASTERN NC.
AVIATION /23Z SATURDAY THROUGH THURSDAY/
AS OF 715 PM SATURDAY...
TAF PERIOD: THE COVERAGE OF CONVECTION HAS DROPPED DRASTICALLY
BETWEEN 21-23Z, AND THERE IS MUCH UNCERTAINTY AS TO WHETHER ANY
ORGANIZED CONVECTION WILL MANAGE TO DEVELOP ONCE AGAIN. CONSIDERING
THERE ARE STILL ISOLATED THUNDERSTORMS, HAVE MAINTAINED THE
TEMPO/PROB30 GROUPS AT RDU/RWI THIS EVENING, BUT HAVE REMOVED THE
PROB30 GROUP FROM FAY AS NO THUNDERSTORMS HAVE MANAGED TO DEVELOP
THAT FAR SOUTH YET. VFR CONDITIONS SHOULD CONTINUE OVERNIGHT,
ALTHOUGH THE PROB30 MENTION WAS KEPT IN FAY AROUND SUNRISE FOR A
POTENTIAL DROP IN CONDITIONS. A WEST-SOUTHWEST WIND WILL DEVELOP
LATE SUNDAY MORNING, AND WITH GREATER COVERAGE OF THUNDERSTORMS
EXPECTED TOMORROW AFTERNOON, HAVE ONCE AGAIN ADDED PROB30 GROUPS AT
ALL TERMINALS EXCEPT FOR FAY, WHERE THE BETTER CHANCE FOR
THUNDERSTORMS WILL OCCUR AFTER 00Z.
OUTLOOK: AN APPROACHING COLD FRONT SUNDAY THAT LINGERS INTO MONDAY
SHOULD RESULT IN SCATTERED TO LOCALLY NUMEROUS SHOWERS AND STORMS
INTO EARLY NEXT WEEK. AREAS OF STRATUS OR FOG WILL BE POSSIBLE EACH
MORNING MON-WED. AFTER A RELATIVE MINIMUM IN STORMS TUESDAY, A
STRONG COLD FRONT WILL RISK ADDITIONAL STORMS WEDNESDAY.
CLIMATE
RECORD HIGH TEMPERATURES:
JULY 18:
KGSO: 97/1986
KRDU: 103/1887
KFAY: 103/1942
JULY 19:
KFAY: 101/2002
RECORD HIGH MINIMUM TEMPERATURES:
JULY 18:
KGSO: 76/1986
KRDU: 80/2025
KFAY: 77/2025
JULY 19:
KGSO: 75/2016
KRDU: 80/1942
KFAY: 77/2023
JULY 20:
KGSO: 75/2019
KRDU: 76/2025
JULY 21:
KGSO: 76/2011
KRDU: 78/1932
KFAY: 80/2017
JULY 22:
KGSO: 77/2011
KRDU: 78/2011
KFAY: 82/2017
RAH WATCHES/WARNINGS/ADVISORIES
HEAT ADVISORY UNTIL 9 PM EDT THIS EVENING FOR NCZ008>011-
024>028-040>043-073>078-083>086-088-089.
DISCUSSION...KREN/BLS
AVIATION...GREEN/KREN
CLIMATE...RAH
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