445
FXUS62 KRAH 220916
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
516 AM EDT WED JUL 22 2026
WHAT HAS CHANGED
* A (FLASH) FLOOD WATCH HAS BEEN ISSUED FOR CENTRAL NC, WITH
STAGGERED STARTING AND ENDING TIMES FROM NORTH TO SOUTH TO ACCOUNT
FOR THE ESTIMATED TIMING OF THE PROGRESSION OF A SLOW-MOVING COLD
FRONT AND FOCUS FOR WAVES OF SHOWERS/STORMS AND HEAVIEST RAINFALL.
KEY MESSAGES
AS OF 500 AM WEDNESDAY...
1) WAVES OF SHOWERS AND THUNDERSTORMS WITH EXCESSIVE RAIN WILL FOCUS
ALONG A SLOW-MOVING, OUTFLOW-REINFORCED/STRENGTHENED COLD FRONT
THROUGH THU-THU NIGHT.
2) THE SLOW MOVING COLD FRONT ACROSS THE CAROLINAS WILL SETTLE SOUTH
AND STALL ACROSS THE SOUTHERN CAROLINAS FOR FRIDAY AND INTO THE
WEEKEND WITH THE AREA OF WIDESPREAD RAIN SHIFTING SOUTH AND THE
RAINFALL INTENSITY DECREASING ON FRIDAY AND ESPECIALLY SATURDAY.
DISCUSSION
AS OF 500 AM WEDNESDAY...
KEY MESSAGE 1... WAVES OF SHOWERS AND THUNDERSTORMS WITH EXCESSIVE
RAIN WILL FOCUS ALONG A SLOW-MOVING, OUTFLOW-REINFORCED/STRENGTHENED
COLD FRONT THROUGH THU-THU NIGHT.
WITHIN A TROUGH ANCHORED BY A MID/UPR-LEVEL CYCLONE THAT WILL LIFT
THROUGH QC, A COMPACT SHORTWAVE PERTURBATION EVIDENT OVER WRN ON IN
GOES-E WATER VAPOR SATELLITE DATA WILL DIG SEWD INTO THE LWR GREAT
LAKES THROUGH THIS EVENING, THEN PROBABLY PHASE WITH THE LIFTING
CYCLONE ACROSS QC THROUGH THU. THE DIGGING WAVE WILL MAINTAIN
GENERALLY NEUTRAL TO WEAKLY RISING HEIGHT TENDENCIES THROUGHOUT THE
MIDDLE ATLANTIC TODAY, FOLLOWED BY MORE-STRONGLY RISING HEIGHTS
WITHIN A WEAKENING ERN CONUS TROUGH THU-THU NIGHT. CNTL NC WILL
REMAIN SITUATED WITHIN THE BASE OF THAT TROUGH AND PROBABLY
INFLUENCED MOST STRONGLY BY MCVS OF VARYING SIZE AND STRENGTH THAT
WILL BOTH PROGRESS NEWD FROM THE TN VALLEY AND SRN APPALACHIANS THIS
MORNING AND ALSO DEVELOP IN SITU FROM REGENERATIVE CONVECTION OVER
THE SRN MIDDLE ATLANTIC, AND ALSO WITHIN A DEEPLY MOIST SWLY FLOW
REGIME CHARACTERIZED BY PWS OF 2-2.5" AND UP TO 125% OR SO OF
NORMAL; WEAKLY VEERING WINDS FROM THE SURFACE THROUGH THE MID-LEVELS
(INDICATIVE OF WAA AND CONTRIBUTION TO QG FORCING FOR ASCENT); AND
UNIFORMLY 30-40 KT WIND SPEEDS IN THE 850-500 MB LAYER. RELATED
SMALL UPWIND PROPAGATION/CORFIDI VECTORS WILL FAVOR TRAINING AND
BACKBUILDING CONVECTION ALONG AND INTO A SIMILARLY-ALIGNED LOW-LEVEL
FRONTAL ZONE THAT WILL STRENGTHEN AND SETTLE VERY SLOWLY SSEWD
ACROSS THE SRN MIDDLE ATLANTIC.
THAT LOW-LEVEL FRONTAL ZONE WILL TEND TO CONSOLIDATE AND STRENGTHEN,
AS A COUPLE OF CLOSELY-SPACED SYNOPTIC FRONTS NOW STRETCHING FROM
THE MIDDLE ATLANTIC TO THE LWR OH VALLEY MERGE AND PROBABLY
ULTIMATELY OVERTAKE AN OUTFLOW-REINFORCED/EFFECTIVE ONE STRETCHING
FROM THE SRN DELMARVA AND SRN VA TO THE CUMBERLAND MOUNTAINS. THAT
EFFECTIVE FRONT WILL CONTINUE TO SETTLE VERY SLOWLY SSEWD AND INTO
THE NRN PIEDMONT AND NRN COASTAL PLAIN OF NC THROUGH EARLY TONIGHT,
WHILE STRENGTHENING FROM REPEATED ROUNDS OF CONVECTION AND DIABATIC
COOLING ALONG IT AND DIFFERENTIAL DIABATIC HEATING TODAY ACROSS IT.
STRENGTHENING FRONTOGENESIS, AND ALSO ISENTROPIC LIFT INDUCED BY A
30-35 KT SWLY LOW-LEVEL JET AND WAA INTERSECTING THE SLOWLY-SSEWD
SETTLING FRONT, WILL FAVOR FOCUSED LIFT IN THE AFOREMENTIONED DEEPLY
MOIST ENVIRONMENT. WHEN COMBINED WITH BROADER LOW/MID-LEVEL WAA
REGIME AND INFLUENCE FROM MCVS, AMID DEEPLY MOIST AND CONDITIONALLY
UNSTABLE PROFILES, THE ENVIRONMENT WILL BE VERY HIGHLY CONDUCIVE FOR
REPEATED ROUNDS OF TRAINING CONVECTION AND RISK OF FLASH FLOODING
INITIALLY ACROSS THE NRN PIEDMONT AND NRN COASTAL PLAIN. THIS RISK
WILL BE GREATEST TONIGHT, WHEN THE BOUNDARY WILL PROBABLY BE SLOWEST-
MOVING AND NEARLY STATIONARY AND ALSO CENTERED MOST-SQUARELY OVER
THE NRN PIEDMONT AND NRN COASTAL PLAIN, INCLUDING OVER THE URBAN
AREAS OF THE GREATER TRIAD AND TRIANGLE. AS THE BOUNDARY LIKELY GETS
OVERTAKEN BY THE UPSTREAM, SYNOPTIC FRONTS, IT WILL PROBABLY
ACCELERATE AND PROGRESS SEWD AND ACROSS THE SANDHILLS, SRN PIEDMONT,
AND CNTL AND SRN COASTAL PLAIN ON THU, WHERE THE FLASH FLOOD RISK
HAS THE POTENTIAL TO BE SOMEWHAT LESS THAN THE ADJACENT PIEDMONT AND
NRN COASTAL PLAIN GIVEN A SHORTER RESIDENCE TIME OF THE STRONGEST
FRONTAL FORCING.
WHILE A FEW STRONG TO SEVERE DOWNBURSTS WILL ALSO BE POSSIBLE, THE
LATEST SWODY1 HAS MOSTLY A MARGINAL (LEVEL 1 OF 5) RISK OVER CNTL
NC; AND THE FLASH FLOOD RISK WILL BE RELATIVELY GREATER AND THE MAIN
STORY.
IT WILL OTHERWISE TREND MARKEDLY MILDER BEHIND THE FRONT THU INTO
FRI, WHEN RECORD LOW MAXIMUM TEMPERATURES HAVE A VERY REALISTIC
CHANCE OF BEING SET.
KEY MESSAGE 2... THE SLOW MOVING COLD FRONT ACROSS THE CAROLINAS
WILL SETTLE SOUTH AND STALL ACROSS THE SOUTHERN CAROLINAS FOR FRIDAY
AND INTO THE WEEKEND WITH THE AREA OF WIDESPREAD RAIN SHIFTING SOUTH
AND THE RAINFALL INTENSITY DECREASING ON FRIDAY AND ESPECIALLY
SATURDAY.
THE MULTI-DAY RAIN EVENT ACROSS THE CAROLINAS WILL BEGIN TO SHIFT
SOUTH AND EAST ON FRIDAY AND BEGIN TO TRANSITION AWAY FROM DEEP
CONVECTION AND EXCESSIVE RAIN ON FRIDAY NIGHT. AS THE FRONT SETTLES
FURTHER SOUTH ON FRIDAY AND DEWPOINTS IN THE LOWER 60S FILTER INTO
THE PIEDMONT, LOW LEVEL INSTABILITY WILL DECREASE ACROSS NORTHERN
PORTIONS OF THE PIEDMONT ON FRIDAY WITH SOME RESIDUAL INSTABILITY
PERSISTING ACROSS THE SANDHILLS AND SOUTHERN COASTAL PLAIN. THUS THE
PRECIPITATION ACROSS THE NORTH SHOULD HAVE FEWER THUNDERSTORMS WITH
HIGH PRECIPITATION RATES AND MORE SHOWERS OR AREAS OF LIGHTER RAIN
ON FRIDAY AS ISENTROPIC LIFT DRIVES MORE OF THE PRECIPITATION. TO
THE SOUTH AND SOUTHEAST, DEW POINTS WILL RANGE IN THE UPPER 60S AND
THE INSTABILITY WILL LINGER SUPPORTING ADDITIONAL THUNDERSTORMS ON
FRIDAY AND POSSIBLY FRIDAY NIGHT. WITH THE DECREASED INSTABILITY AND
LIGHTER FLOW ALOFT, THE SEVERE STORM RISK IS GREATLY REDUCED AND
SHIFTED INTO SC. WPC QPF AMOUNTS FOR FRIDAY AND FRIDAY NIGHT RANGE
AROUND A 0.3 INCHES IN THE TRIAD, 0.5 TO 0.75 INCHES IN THE TRIANGLE
AND 1 TO 1.5 INCHES IN THE SANDHILLS.
RAIN AMOUNTS AND INTENSITY SHOULD IN GENERAL SHIFT SOUTH AND
DECREASE FURTHER ON SATURDAY AS THE FRONT SETTLES SOUTH. A SHORT
WAVE TROUGH DIVES ACROSS THE TN VALLEY AND INTO GA AND SC ON
SATURDAY AFTERNOON. THIS COULD SUPPORT AN UPTICK IN SHOWERS AND
STORMS IN SOUTHERN AREAS NEAR THE NC/SC BORDER DURING THE AFTERNOON
AND EVENING WHILE RAIN AMOUNTS ACROSS THE NORTH REMAIN RATHER LIGHT.
WPC QPF AMOUNTS FOR SATURDAY AND SATURDAY NIGHT RANGE BETWEEN 0.10
AND 0.20 INCHES IN THE TRIAD, AROUND 0.25 INCHES IN THE TRIANGLE BUT
0.5 TO 0.75 INCHES IN THE SANDHILLS.
THE CLOUDS AND PRECIPITATION ON FRIDAY AND SATURDAY WILL RESULT IN
HIGH TEMPERATURES AROUND 5 TO 10 DEGREES BELOW AVERAGE IN THE UPPER
70S TO LOWER 80S.
IT APPEARS THAT A LESS ACTIVE PATTERN AND DRIER WEATHER ARRIVES FOR
SUNDAY AND MONDAY AS THE UPPER TROUGH SLIPS EAST BEFORE RAIN CHANCES
NUDGE BACK UP A BIT ON TUESDAY.
AVIATION /06Z WEDNESDAY THROUGH SUNDAY/
AS OF 150 AM WEDNESDAY...
TAF PERIOD: WIDESPREAD VFR CONDITIONS ACROSS CENTRAL NC EARLY
THIS MORNING ARE LIKELY TO CONTINUE THROUGH MUCH OF THE OVERNIGHT. A
FEW ROGUE SHOWERS ARE POSSIBLE ACROSS CENTRAL NC ALTHOUGH THEY WILL
BE ISOLATED WITH MUCH MORE WIDESPREAD CONVECTION ACROSS VA, WV, AND
TN. SKIES WILL GENERALLY BE FAIR OVERNIGHT WITH SOME SCT TO POSSIBLE
BKN MID AND HIGH CLOUDS. SOUTHWESTERLY WINDS WILL CONTINUE OVERNIGHT
AT 6 TO 12 KTS WITH GUSTS OF 14 TO 20 KTS. A LOW LEVEL JET
WILL STRENGTHEN OVERNIGHT AND SOME PATCHY LLWS IS POSSIBLE THRU
DAYBREAK IF SURFACE WINDS RELAX BUT IT APPEARS THAT WINDS SHOULD
STAY UP OVERNIGHT FOR THE MOST PART AND ANY LLWS WILL BE PATCHY.
A COLD FRONT WILL SAG SOUTH ACROSS THE VIRGINIAS AND TENNESSE TODAY
AND A REGION OF SHOWERS AND THUNDERSTORMS WILL SHIFT SOUTH INTO
CENTRAL NC BEGINNING AROUND MIDDAY AND SLOWLY SETTLING SOUTHWARD
DURING THE AFTERNOON AND EVENING. THE CONVECTION WILL FIRST IMPACT
THE KGSO/KINT TERMINALS BETWEEN 16 AND 20Z, KRDU/KRWI BETWEEN 18
AND 22Z AND KFAY AFTER 22Z. THE CONVECTION WILL RESULT IN PERIOD OF
IFR VSBY RESTRICTIONS, OCCASIONALLY MVFR CIG RESTRICTIONS
AND LOCALLY GUSTY WINDS. ON AND OFF SHOWERS AND STORMS ARE APT TO
CONTINUE WELL INTO TONIGHT WITH MORE WIDESPREAD CIG RESTRICTIONS
SPREADING SOUTH ACROSS THE AREA AFTER MIDNIGHT. SOUTHWESTERLY WINDS
AT 10 TO 14KTS WITH GUSTS OF 18 TO 24KTS ARE EXPECTED AFTER
DAYBREAK THROUGH THIS AFTERNOON WITH THE WINDS RELAXING A BIT DURING
THE MID AND LATE AFTERNOON. WINDS WILL SHIFT TO WESTERLY AND THEN
NORTHWESTERLY AND DECREASING FURTHER BEHIND THE FRONT AS IT MOVES
ACROSS THE AREA TONIGHT.
OUTLOOK: WIDESPREAD SHOWERS AND STORMS WILL RESULT IN ADVERSE
AVIATION CONDITIONS WITH VSBY AND CIG RESTRICTIONS ON THURSDAY
AND THURSDAY NIGHT ACROSS CENTRAL NC. THE FOCUS FOR THE CONVECTION
WILL SHIFT SLOWLY SOUTH INTO SOUTHERN NC LATE THURSDAY AND FRIDAY
WITH COVERAGE DECREASING NOTABLY AND SHIFTING FURTHER SOUTH ON
SATURDAY. AVIATION CONDITIONS WILL IMPROVE ON SUNDAY WITH A LIMITED
CHANCE OF SHOWERS.
CLIMATE
RECORD LOW MAXIMUM TEMPERATURES:
JULY 23: KGSO: 73/2019 KRDU: 76/1921
JULY 24: KFAY: 81/1985
RAH WATCHES/WARNINGS/ADVISORIES
FLOOD WATCH FROM 9 AM EDT THIS MORNING THROUGH THURSDAY EVENING FOR
NCZ007>011-021>025.
FLOOD WATCH FROM THIS EVENING THROUGH THURSDAY EVENING FOR
NCZ026>028-038>041.
FLOOD WATCH FROM LATE TONIGHT THROUGH FRIDAY MORNING FOR NCZ042-043-
073>078-083>086-088-089.
DISCUSSION...MWS/BLAES
AVIATION...BLAES
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