572
FXUS62 KRAH 191016
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
615 AM EDT SAT SEP 19 2026
WHAT HAS CHANGED
* A FEW ISOLATED SHOWERS OR A STORM ARE POSSIBLE IN THE SOUTHERN
PIEDMONT, SANDHILLS, AND SOUTHERN COASTAL PLAIN TODAY.
* A DECAYING STORM COMPLEX IN THE OH VALLEY COULD BRING A FEW
ISOLATED SHOWERS IN THE TRIAD EARLY SUNDAY, BUT CONFIDENCE ON
THAT IS LOW.
KEY MESSAGES
AS OF 140 AM SATURDAY...
1) A FEW ISOLATED SHOWERS OR STORMS ARE POSSIBLE IN THE SOUTH
AND WEST TODAY AND EARLY SUNDAY.
2) SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ARE EXPECTED
ON MONDAY AND TUESDAY. LOCALLY EXCESSIVE RAINFALL WILL BE
POSSIBLE.
3) A CAD PATTERN LOOKS TO SET UP FROM MID TO LATE NEXT WEEK,
RESULTING IN MOSTLY CLOUDY SKIES, PATCHY LIGHT RAIN AND DRIZZLE,
AND BELOW-NORMAL HIGH TEMPERATURES.
DISCUSSION
AS OF 140 AM SATURDAY...
KEY MESSAGE 1... A FEW ISOLATED SHOWERS OR STORMS ARE POSSIBLE IN
THE SOUTH AND WEST TODAY AND EARLY SUNDAY.
WEAK HIGH PRESSURE WILL BUILD IN LATER TODAY AND TONIGHT INTO SUNDAY
FROM THE NORTHEAST. A COLD FRONT PRESENTLY ACROSS SOUTH-CENTRAL
VIRGINIA WILL MOVE THROUGH THIS MORNING AND SETTLE INTO SOUTH
CAROLINA THIS EVENING AND SUNDAY. TO THE WEST OF US, A WARM FRONT
WILL SET UP ACROSS THE MID MS AND WESTERN OH VALLEY REGION IN
RESPONSE TO LOW PRESSURE DEVELOPMENT ACROSS THE MIDWEST.
MORNING TO EARLY AFTERNOON STRATUS WILL GRADUALLY GIVE WAY TO
SUNSHINE AND HIGHS IN THE LOW TO MID 80S. FORECAST MODELS INDICATE A
GRADUAL LOWERING OF DEWPOINTS FROM THE NORTH AND EAST BEHIND THE
FRONT AND WITHIN NORTHEAST FLOW. HOWEVER, LINGERING LOW TO MID 70S
DEWPOINTS ARE EXPECTED IN THE SOUTHERN PIEDMONT, SANDHILLS, AND
SOUTHERN COASTAL PLAIN. INSTABILITY OF 1000-1500 J/KG MAY EMERGE
EARLY THIS AFTERNOON TO PROMOTE A FEW ISOLATED STORMS ACROSS OUR
SOUTH AND SOUTHWEST ALONG THE SOUTHWARD MOVING FRONT AND SEA-BREEZE.
A FEW OF THE HREF MEMBERS, SPECIFICALLY THE HRRR/NAM-NEST, INDICATE
A DECAYING STORM COMPLEX TIED TO THE WARM FRONT TRACKING FROM THE OH
VALLEY INTO THE NORTHWEST PIEDMONT AND TRIAD EARLY SUNDAY MORNING.
INSTABILITY IS EXPECTED TO BE WEAK, IF AT ALL PRESENT, THUS LIMITING
ITS EASTWARD PROGRESSION. CONFIDENCE ON THIS SCENARIO IS LOW, BUT
CERTAINLY CANNOT RULE IT OUT. ANY SHOWERS WOULD BE MINOR AT THIS
STAGE. OTHERWISE, MORNING STRATUS IS POSSIBLE OVER CENTRAL NC SUNDAY
MORNING.
KEY MESSAGE 2... SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ARE
EXPECTED ON MONDAY AND TUESDAY. LOCALLY EXCESSIVE RAINFALL WILL BE
POSSIBLE.
ALOFT, A NRN STREAM S/W LOW WILL TRACK EWD ACROSS THE NRN PLAINS AND
UPPER MS VALLEY MON AND TUE, AMPLIFYING THE TROUGH TO THE WEST. AT
THE SURFACE, A BACKDOOR COLD FRONT WILL APPROACH FROM THE NORTH ON
MON, EVENTUALLY MAKING ITS WAY ACROSS THE AREA MON NIGHT/TUE AS HIGH
PRESSURE RIDGES IN. AN AREA OF LOW PRESSURE MAY LIFT NEWD ALONG/OFF
THE SOUTHEAST AND CAROLINA COASTS THROUGH TUE NIGHT, INCREASING THE
PRESSURE GRADIENT ACROSS THE REGION. GFS FORECAST SOUNDINGS SHOW
PWAT VALUES OF 1.7-2.0" ACROSS THE AREA, WITH SBCAPE OF 500-1200
J/KG AND 0-6 BULK SHEAR OF ABOUT 10 KTS. DEPENDING ON THE TIMING OF
THE FRONT, THERE COULD BE SOME LINGERING INSTABILITY EARLY TUE IN
AREAS SOUTH OF IT. SHOWERS AND THUNDERSTORMS ARE EXPECTED MON AND
TUE, WITH THE POTENTIAL FOR LOCALLY EXCESSIVE RAINFALL. THE WPC
STILL HAS ALL OF CENTRAL NC IN A MARGINAL RISK (LEVEL 1 OF 4) FOR
EXCESSIVE RAINFALL BOTH DAYS, WITH A SLIGHT RISK STILL CLIPPING THE
NRN COASTAL PLAIN ON TUE. HIGHS MON SHOULD STILL BE WELL ABOVE
NORMAL, MID 80S TO AROUND 90 DEGREES, DECREASING TO NEAR NORMAL FOR
TUE IN THE WAKE OF THE FRONT.
KEY MESSAGE 3... A CAD PATTERN LOOKS TO SET UP FROM MID TO LATE NEXT
WEEK, RESULTING IN MOSTLY CLOUDY SKIES, PATCHY LIGHT RAIN AND
DRIZZLE, AND BELOW-NORMAL HIGH TEMPERATURES.
MID/UPPER TROUGHING WILL STRENGTHEN AND BUILD INTO THE EASTERN US
FROM WEDNESDAY THROUGH FRIDAY. MEANWHILE, ANOMALOUSLY STRONG SURFACE
HIGH PRESSURE WILL NOSE DOWN FROM SE CANADA AND NORTHERN NEW ENGLAND
INTO THE LEE SIDE OF THE APPALACHIANS, AS A SURFACE LOW DRIFTS NORTH
IN THE WESTERN ATLANTIC, THOUGH MODELS DIFFER SUBSTANTIALLY ON ITS
PLACEMENT. THIS WILL RESULT IN ROBUST N/NE LOW-LEVEL FLOW AND A
LIKELY CAD PATTERN ACROSS THE SOUTHERN MID-ATLANTIC. CURRENT
FORECAST HIGHS ARE IN THE UPPER-60S TO UPPER-70S, BUT SOME RAW
GUIDANCE SUCH AS THE GFS IS EVEN COOLER. FORECAST LOWS ARE GENERALLY
MID-50S TO MID-60S. POPS ARE IN THE SLIGHT TO LOW CHANCE RANGE, AND
GIVEN THE STABLE CAD REGIME, PRECIPITATION IS MORE LIKELY TO BE OF
THE STRATIFORM VARIETY (PATCHY LIGHT RAIN AND DRIZZLE) AS OPPOSED TO
CONVECTIVE.
AVIATION /12Z SATURDAY THROUGH WEDNESDAY/
AS OF 615 AM SATURDAY...
THE LOW STRATUS HAS BEEN SLOW TO DEVELOP EARLY THIS MORNING, LIKELY
DUE TO THE SLOWER ARRIVAL OF THE BACKDOOR COLD FRONT. THE LATEST
ANALYSIS INDICATES THE FRONT IS ACROSS THE NC/VA BORDER, PROGRESSING
SOUTH AND WEST THIS MORNING. SOME ASOS/AWOS SITES ARE REPORTING MVFR
STRATUS, BUT IT IS STILL ISOLATED IN NATURE. CURRENT THINKING
CONTINUES TO FAVOR THE DEVELOPMENT OF STRATUS AROUND OR SHORTLY
AFTER DAYBREAK, AS HEATING FAVORS MIXING AND SATURATION IN THE LOW-
LEVELS OF THE ATMOSPHERE. OVERALL CONFIDENCE IN THE EXTENT OF THE
SUB-VFR STRATUS IS LOW GIVEN SLOW DEVELOPMENT. WE CANNOT RULE OUT A
FEW PATCHY AREAS OF IFR, BUT THIS IS NO LONGER EXPECTED TO BE
WIDESPREAD AS BEFORE. EXPECT A LIFT FROM MVFR TO VFR BETWEEN 15 AND
18Z TODAY. A STRAY ISOLATED SHOWER/STORM IS POSSIBLE, MOST FAVORED
AT FAY. HOWEVER, CONFIDENCE WAS TOO LOW TO INCLUDE. REDEVELOPMENT OF
STRATUS AND PATCHY FOG IS EXPECTED SUNDAY MORNING, MOST FAVORED IN
THE TRIAD TERMINALS AND FAY/RWI.
OUTLOOK: A COLD FRONT APPROACHING MONDAY WILL BRING A GOOD CHANCE OF
SHOWERS AND STORMS. UNSETTLED WEATHER MAY PERSIST UNDER A CAD-REGIME
DEVELOPING TUESDAY-WEDNESDAY, WHERE PERIODS OF SUB-VFR STRATUS MAY
EXIST INTO LATE WEEK.
RAH WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION...KREN/10/DANCO
AVIATION...KREN
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