516
FXUS62 KRAH 160006
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
806 PM EDT SAT AUG 15 2026
WHAT HAS CHANGED
* ANOTHER HEAT ADVISORY HAS BEEN ISSUED FOR SUNDAY FOR MUCH OF SOUTH
CENTRAL NC PLUS THE TRIANGLE. BUT MORNING STRATUS COULD LIMIT
STRONG HEATING IN SOME AREAS TOMORROW.
* SCATTERED STRONG TO SEVERE THUNDERSTORMS REMAIN POSSIBLE THROUGH
THIS EVENING, WITH A FOCUS ON THE W AND S PIEDMONT AND FAR SE.
* CONFIDENCE INCREASING THAT MON WILL BE THE HOTTEST DAY OF THIS
STRETCH, WITH SEVERAL 100F AIR TEMPS POSSIBLE.
KEY MESSAGES
AS OF 315 PM SATURDAY...
1) ANOTHER HEAT ADVISORY HAS BEEN ISSUED FOR PARTS OF THE TRIANGLE
AND SOUTH CENTRAL NC FOR SUN. THE HOT WEATHER WILL CONTINUE INTO MID
WEEK, PEAKING ON MONDAY WHEN MOST OF THE AREA WILL HAVE HEAT INDEX
VALUES NEAR OR OVER 105F, AND OUR SOUTHEAST COULD SEE 110F OR HIGHER.
2) A MARGINAL (LEVEL 1 OF 5) RISK OF SEVERE THUNDERSTORMS CONTINUES
THROUGH THIS EVENING OVER ALL OF CENTRAL NC, AND OVER THE NORTH
SUNDAY. DAMAGING WINDS ARE THE PRIMARY THREAT.
DISCUSSION
AS OF 315 PM SATURDAY...
KEY MESSAGE 1... ANOTHER HEAT ADVISORY HAS BEEN ISSUED FOR PARTS OF
THE TRIANGLE AND SOUTH CENTRAL NC FOR SUN. THE HOT WEATHER WILL
CONTINUE INTO MID WEEK, PEAKING ON MONDAY WHEN MOST OF THE AREA WILL
HAVE HEAT INDEX VALUES NEAR OR OVER 105F, AND OUR SOUTHEAST COULD
SEE 110F OR HIGHER.
STRONG HEATING ACROSS SOUTHERN PORTIONS OF CENTRAL NC ALONG WITH
HIGH DEWPOINTS HAVE PUSHED HEAT INDEX VALUES TO AROUND 105F TODAY,
WHILE OVER NE AND FAR N SECTIONS, THIS MORNING'S SCT-BKN STRATUS
CURBED HEATING A BIT, KEEPING HEAT INDICES IN THE 90S TO AROUND
100F. THESE CLOUDS WERE ALONG AND NE OF A SURFACE BOUNDARY EVIDENT
IN RECENT ANALYSES STRETCHING OVER NW INTO E NC, WITH SLIGHTLY MORE
STABLE AIR NOTED EARLIER TODAY NE OF THIS BOUNDARY. THIS BOUNDARY
SHOULD WASH OUT AND DISSIPATE LATE TONIGHT, PUTTING US BACK INTO A
LIGHT FLOW FROM THE SSE TO SW SUN AND PUSHING HIGH TEMPS WELL INTO
THE 90S MOST AREAS. DESPITE SOME MODEST MIXING OF SURFACE DEWPOINTS
SUN AFTERNOON, READINGS SHOULD STILL HOLD IN THE LOW-MID 70S, WITH
SOME UPPER 70S PERSISTING OVER PARTS OF THE COASTAL PLAIN, AND THIS
WILL RESULT IN HEAT INDEX VALUES PEAKING AROUND 105 TO 109 OVER MUCH
OF OUR SOUTHERN HALF AND TRIANGLE REGION, WHERE HEAT ISLAND EFFECTS
COULD FURTHER BOOST LOCAL TEMPS. WE'VE ISSUED ANOTHER HEAT ADVISORY
FOR SUN FOR THIS AREA. BUT THERE IS SOME UNCERTAINTY WITH THIS, AS
OUR CONFIDENCE IS INCREASING THAT WE'LL HAVE AREAS OF LOW STRATUS
AROUND THE AREA SUN MORNING, NOT DISSIPATING SUBSTANTIALLY UNTIL
LATE MORNING OR THE NOON HOUR, WHICH COULD PUT A DAMPER ON STRONG
HEATING IN SOME AREAS. IF THIS OCCURS, HEAT INDEX VALUES COULD BE A
BIT LOWER THAN EXPECTED, ALTHOUGH THIS COULD BE BALANCED BY LESS
MIXING OF SURFACE DEWPOINTS. OTHERWISE, THICKNESSES ARE PROJECTED TO
BE AROUND 10 M ABOVE NORMAL, SO HIGHS WELL INTO THE 90S REMAIN
PLAUSIBLE.
THIS HOT STRETCH IS LIKELY TO BE ITS WORST ON MON, WHEN HIGHS ARE
EXPECTED TO REACH THE MID 90S TO AROUND 100F AREAWIDE, WITH ELEVATED
DEWPOINTS PERSISTING, PUSHING THE HEAT INDEX OVER 105F OVER ALL BUT
THE FAR N, AND PERHAPS OVER 110F OVER OUR FAR SE. IF CONFIDENCE IN
THIS CONTINUES TO GROW, ADDITIONAL HEAT ADVISORIES WILL BE NEEDED,
AND AN EXTREME HEAT WATCH OR WARNING MAY BE CONSIDERED IN SOME
AREAS FOR MON.
TEMPS WILL REMAIN ABOVE NORMAL WITH HIGH HUMIDITY THROUGH MID WEEK,
BUT WITH SLIGHTLY LOWER INTENSITY. THE MID LEVEL RIDGE TO OUR S WILL
GRADUALLY RETROGRADE IN RESPONSE TO A SOUTHWARD PROGRESSION OF THE
FLAT NW FLOW FROM THE MIDWEST THROUGH VA/NC, NUDGING THICKNESSES
DOWN A BIT, ALTHOUGH OUR SW AREAS MAY STAY ATYPICALLY HOT INTO LATE
WEEK.
KEY MESSAGE 2... A MARGINAL (LEVEL 1 OF 5) RISK OF SEVERE
THUNDERSTORMS CONTINUES THROUGH THIS EVENING OVER ALL OF CENTRAL NC,
AND OVER THE NORTH SUNDAY. DAMAGING WINDS ARE THE PRIMARY THREAT.
FOR ANOTHER DAY, WE'RE IN A REGIME FEATURING HIGH PW AOA 2" AND MDT-
HIGH SBCAPE OF 1500-3000 J/KG, HIGHEST IN THE S AND FAR W, BUT WITH
MODEST MID LEVEL LAPSE RATES AND POOR DEEP LAYER BULK SHEAR,
PARTICULARLY IN THE AREA OF HIGHEST CAPE, RESULTING IN LOW OVERLAP
OF THE MOST FAVORABLE CAPE/SHEAR. PREDICTABILITY OF PRECISE LOCATION
AND TIMING OF CONVECTION REMAINS SOMEWHAT LOW BEYOND THE FIRST 24
HOURS, AS THE PRIMARY FEATURES THAT ARE FOCUSING CONVECTION REMAIN
MULTIPLE WEAK OUTFLOWS FROM UPSTREAM CONVECTIVE SYSTEMS, ALONG WITH
THE SEA BREEZE AND TERRAIN-FAVORED STORMS ROLLING INTO THE W
PIEDMONT. THE SUB-20-KT DEEP LAYER SHEAR WILL CONTINUE TO LIMIT
STORM ORGANIZATION AND LONGEVITY, BUT A FEW STRONG STORMS PRODUCING
WATER-LOADED DOWNDRAFTS REMAIN POSSIBLE THROUGH MID EVENING. THIS
OVERALL REGIME WILL HOLD FOR SUN AS WELL, PRIMARILY (BUT NOT SOLELY)
ACROSS THE NORTH AS OUTFLOWS DRIFT IN FROM THE NW AND N, AND WHERE
PWS ARE EXPECTED TO BE A BIT HIGHER AS COMPARED TO OUR SW SECTIONS.
AVIATION /00Z SUNDAY THROUGH THURSDAY/
AS OF 800 PM SATURDAY...
RICH LOW-LVL MOISTURE WITHIN THE NORTHEAST FLOW IN THE LOWEST 100MB
REMAINS OVER THE AREA AFTER BEING DEPOSITED EARLIER THIS MORNING. AS
THE BOUNDARY LAYER COOLS, WIDESPREAD IFR/LIFR STRATUS IS EXPECTED,
AND PERSISTING LONGEST AROUND RDU/FAY. ON THE PERIPHERY, THERE IS
LESS FORECAST CONFIDENCE IN ONSET AND DURATION AS DRIER AIR FILTERS
IN OFF THE WESTERN ATLANTIC IN THE EAST, AND WESTERLY WEAKLY
DOWNSLOPING FLOW IN THE WEST. SLOW RISE IN CIGS IS EXPECTED IN THE
HEART OF THE STRATUS COVERAGE SUN MORNING WHILE QUICKER EROSION IS
EXPECTED ON THE PERIPHERY. SCATTERED SHOWERS/STORMS ARE POSSIBLE,
WITH HIGHEST CONFIDENCE AROUND RDU/RWI BETWEEN 21Z AND 03Z.
LOOKING BEYOND 18Z SUN, SCATTERED LATE-DAY SHOWERS AND STORMS ARE
POSSIBLE AGAIN MON, WITH THE BETTER CHANCES THEN SHIFTING TO JUST
SOUTH AND SOUTHEAST AREAS FOR TUE-THU. OUTSIDE OF STORMS, GENERALLY
VFR CONDITIONS ARE EXPECTED, ALTHOUGH A FEW HOURS OF PATCHY EARLY-
MORNING SUB-VFR FOG/STRATUS MAY OCCUR EACH DAY, WITH THE HIGHEST
CHANCES IN AREAS THAT SEE RAIN.
CLIMATE
RECORD HIGH TEMPERATURES:
AUGUST 17: KRDU: 99/1997 KFAY: 104/1954
AUGUST 18: KFAY: 98/1988
RECORD HIGH MINIMUM TEMPERATURES:
AUGUST 15: KGSO: 77/1995 KRDU: 77/1995 KFAY: 78/2017
AUGUST 16: KGSO: 75/2016 KRDU: 76/2007 KFAY: 78/2005
AUGUST 17: KGSO: 75/2010 KRDU: 76/2024 KFAY: 78/2007
AUGUST 18: KGSO: 75/2017 KRDU: 77/1995 KFAY: 78/2021
RAH WATCHES/WARNINGS/ADVISORIES
HEAT ADVISORY FROM 11 AM TO 8 PM EDT SUNDAY FOR NCZ025-040>042-
073>077-083>086-088-089.
DISCUSSION...HARTFIELD
AVIATION...AS/HARTFIELD
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