567
FXUS62 KRAH 120742
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
340 AM EDT MON MAY 12 2025
SYNOPSIS
A SLOW MOVING UPPER LOW CENTERED OVER THE LOWER MISSISSIPPI
RIVER VALLEY WILL DRIFT NORTHEAST THROUGH THE MID SOUTH TO THE
CENTRAL APPALACHIANS THROUGH WEDNESDAY, BRINGING WET AND UNSETTLED
WEATHER TO THE REGION.
NEAR TERM /TODAY AND TONIGHT/
AS OF 340 AM MONDAY...
..A FLOOD WATCH IS IN EFFECT THROUGH TUESDAY MORNING
A NEARLY STATIONARY UPPER LEVEL LOW THAT HAS BEEN CHURNING OVER THE
MOUTH OF THE MISSISSIPPI THIS PAST WEEKEND, WILL FINALLY BEGIN TO
MOVE NORTH TOWARDS THE TENNESSEE VALLEY. WEAK INSITU CAD WILL REMAIN
HANG ON ACROSS MUCH OF THE AREA, AHEAD OF THE ATTENDANT WARM FRONT
AND POTENTIAL WEAK TRIPLE POINT LOW FORECAST TO EXTEND ALONG THE SC-
NC STATE LINE BY DAYBREAK TUESDAY.
BENEATH INCREASING UPPER LEVEL DIFFLUENCE, A PLUME OF STRONG
SOUTHERLY MOISTURE TRANSPORT WILL SPREAD ACROSS THE AREA THROUGH
EARLY TUESDAY. THIS ANOMALOUS MOISTURE, COMBINED WITH DEEP LAYER
ASCENT, WILL SPAWN REPEATED ROUNDS OF SHOWERS AND THUNDERSTORMS THIS
MORNING THROUGH TONIGHT. THE SLOW PROGRESSION OF THIS SYSTEM AND
POTENTIAL FOR TRAINING CONVECTION RAISE CONCERNS FOR ISOLATED TO
WIDELY SCATTERED FLASH FLOODING, PARTICULARLY BY THE AFTERNOON AND
EVENING IN AREAS THAT EXPERIENCE MULTIPLE ROUNDS OF HEAVY CONVECTIVE
RAINFALL AS BL DEWPOINTS INCREASE 65-70 AND WEAK INSTABILITY
DEVELOPS.
RAINFALL AMOUNTS THROUGH TONIGHT ARE EXPECTED TO AVERAGE BETWEEN 1-
2" ACROSS CENTRAL NC, WITH LOCALIZED HEAVIER AMOUNTS OF 2-4"
POSSIBLE WHERE TRAINING CONVECTIVE BANDS LINE UP. URBAN AREAS, POOR-
DRAINAGE ROADS, AND SMALL STREAMS WILL BE THE MOST SUSCEPTIBLE. SOME
RIVER FLOODING IS ALSO POSSIBLE, MAINLY ALONG THE HAW AND ROCKY
RIVERS.
HIGHS RANGING FROM NEAR 70 ACROSS THE NORTHERN PIEDMONT TO MID 70S
ACROSS THE COASTAL PLAIN AND EASTERN SANDHILLS. LOWS IN THE LOWER TO
MID 60S.
SHORT TERM /TUESDAY AND TUESDAY NIGHT/
AS OF 415 PM SUNDAY...
THE CLOSED MID/UPPER LOW CENTERED OVER THE TN VALLEY WILL MOVE NE ON
TUESDAY, REACHING THE OH VALLEY AND CENTRAL APPALACHIANS ON TUESDAY
NIGHT AND OPENING UP INTO A WAVE. MEANWHILE THE OCCLUDED SURFACE LOW
WILL DRIFT EAST AND WEAKEN FURTHER, REACHING THE SOUTHERN
APPALACHIANS ON TUESDAY NIGHT. THERE WILL CONTINUE TO BE A DEEP
STREAM OF ATLANTIC MOISTURE AHEAD OF THE MID/UPPER LOW, BUT THE
GREATEST PW AXIS OF 1.5+" WILL MOSTLY SHIFT NE INTO CENTRAL AND
EASTERN VA BY THIS POINT AS THE LOW SHIFTS NE. HOWEVER, WITH MUCAPE
OF 1500 TO AS MUCH AS 2500 J/KG DEPICTED ON MODEL GUIDANCE, THERE
COULD STILL BE SOME POCKETS OF HEAVY RAIN RATES ACROSS CENTRAL NC,
PARTICULARLY OVER THE NE PIEDMONT AND NORTHERN COASTAL PLAIN. THUS
THE WPC HAS OUR REGION IN A LEVEL 1 OF 4 (MARGINAL) RISK FOR
EXCESSIVE RAINFALL ON TUESDAY. ADDITIONAL QPF ON TUESDAY/TUESDAY
NIGHT IS GENERALLY IN THE HALF INCH TO INCH RANGE ON AVERAGE ACROSS
THE NE, WITH LESSER AMOUNTS IN THE SOUTH AND WEST. LOCALLY HIGHER
AMOUNTS WILL BE POSSIBLE IN ANY STORMS, AND BY THIS POINT THE GROUND
SHOULD BE SATURATED ENOUGH THAT IT WON'T TAKE MUCH ADDITIONAL
RAINFALL TO CAUSE MORE FLOODING CONCERNS, AND THERE IS A CHANCE THE
FLOOD WATCH WILL HAVE TO BE EXTENDED BEYOND 12Z TUESDAY. MODELS HAVE
BEEN TRENDING FASTER WITH THE SYSTEM, AND IF THIS CONTINUES, THAT
WOULD LESSEN THESE CONCERNS. IT IS UNCLEAR WHETHER THERE WILL BE
ENOUGH SHEAR AVAILABLE FOR ORGANIZED CONVECTION, SO WHILE A FEW
STRONG STORMS WITH LOCALLY STRONG WINDS AND SMALL HAIL CAN'T BE
RULED OUT, SPC ONLY HAS AN AREA OF DAY 3 GENERAL THUNDER FOR NOW.
TUESDAY'S TEMPERATURES WILL BE KEPT DOWN BY THE WIDESPREAD CLOUDS
AND PRECIPITATION, WITH FORECAST HIGHS IN THE MID-TO-UPPER-70S.
SHOWER AND STORM CHANCES WILL LESSEN ON TUESDAY NIGHT, BUT WITH
WIDESPREAD CLOUD COVER, LOWS WILL STILL BE MILD, IN THE LOWER-TO-MID-
60S.
LONG TERM /WEDNESDAY THROUGH SUNDAY/
AS OF 415 PM SUNDAY...
SHOWER COVERAGE WILL DECREASE SOMEWHAT ON WEDNESDAY AS THE LOW LIFTS
FURTHER NORTH, SO CAPPED POPS AT LIKELY, AGAIN HIGHEST IN THE NE.
AGAIN A FEW STORMS CAN'T BE RULED OUT WITH WEAK TO MODERATE
DESTABILIZATION, BUT NOT EXPECTING ANYTHING SEVERE AS THE MID-LEVEL
FLOW WILL BE EVEN MORE DIMINISHED BY THIS POINT. FORECAST HIGHS ARE
MID-70S TO LOWER-80S. DRIER AIR FROM NW FLOW ALOFT SHOULD REALLY
BEGIN TO MOVE IN ON WEDNESDAY NIGHT AS THE MID-LEVEL TROUGH FINALLY
PUSHES TO OUR EAST. LOWS SHOULD BE IN THE UPPER-50S TO MID-60S.
MID-LEVEL RIDGING WILL BUILD TO OUR WEST ON THURSDAY AND MOVE
OVERHEAD ON THURSDAY NIGHT, GETTING REPLACED BY FAST ZONAL FLOW
ACROSS CENTRAL NC ON FRIDAY AND SATURDAY AS THE RIDGE FLATTENS. THUS
WIDESPREAD UPPER FORCING WILL BE LACKING, AND WE WILL INSTEAD MOSTLY
RELY ON DAYTIME HEATING AND BOUNDARY LAYER DESTABILIZATION FOR
AFTERNOON/EVENING SHOWERS AND STORMS, ALONG WITH POSSIBLE MCS'S FROM
THE MIDWEST TRACKING NEAR OUR REGION. HOWEVER, THESE MCS'S ARE
IMPOSSIBLE TO PINPOINT WITH ANY SPECIFICITY THIS FAR OUT. SO POPS
ARE ONLY IN THE SLIGHT TO LOW CHANCE RANGE EACH DAY, INCREASING A
BIT TO CHANCE EVERYWHERE ON SATURDAY. MODERATE DESTABILIZATION WILL
BE POSSIBLE, PERHAPS EVEN STRONG (2000-3000+ J/KG OF CAPE) ON FRIDAY
ACCORDING TO LATEST GUIDANCE. SO A FEW STRONG TO SEVERE STORMS CAN'T
BE RULED OUT EACH DAY. TEMPERATURES WILL ALSO BE ON THE INCREASE,
WITH HIGHS IN THE MID-TO-UPPER-80S ON THURSDAY AND UPPER-80S TO MID-
90S ON FRIDAY, THEN DECREASING A BIT TO MID-80S TO LOWER-90S ON
SATURDAY WITH BETTER CONVECTION CHANCES. DEW POINTS WILL RISE TO THE
UPPER-60S AND POSSIBLY LOWER-70S ON FRIDAY AND SATURDAY, SO HEAT
INDICES WILL BE A CONCERN BOTH DAYS, ESPECIALLY ON FRIDAY WHEN THEY
COULD REACH THE MID-90S TO 100 IN THE SOUTH AND EAST. CONFIDENCE IN
THE OVERALL PATTERN IS QUITE LOW BY SUNDAY AS THE ECMWF AND MANY OF
ITS ENSEMBLES DRY US OUT BEHIND A COLD FRONT, WHILE THE GFS/GEFS AND
SLOWER WITH THE FRONT, THUS KEEPING US WARM AND WET. FOR NOW JUST
CONTINUE THE SLOW DECREASING TREND IN TEMPERATURES, WITH POPS IN THE
SLIGHT CHANCE RANGE.
AVIATION /06Z MONDAY THROUGH FRIDAY/
AS OF 220 AM MONDAY...
THROUGH 06Z TUESDAY: CONDITIONS WILL CONTINUE TO DETERIORATE WITH
CEILINGS LOWERING TO LIFR TO IFR THROUGH DAYBREAK AS WIDESPREAD
SHOWERS AND RAIN OVERSPREAD THE AREA FROM THE SOUTH. ADDITIONALLY,
BEFORE THE RAIN MOVES IN, A PERIOD OF PATCHY FOG IS POSSIBLE, WITH
VSBYS POTENTIALLY DROPPING TO LESS THAN A MILE AT TIMES.
EXPECT LITTLE TO NO IMPROVEMENT THROUGH THE FORECAST PERIOD AS
WIDESPREAD SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE TO
REDEVELOP ACROSS THE AREA THROUGH TONIGHT. RESTRICTIONS SHOULD
REMAIN PREDOMINATELY IFR THROUGH THE EVENING, BEFORE POTENTIALLY
LOWERING TO LIFR TONIGHT/EARLY TUESDAY.
AFTER 06Z TUESDAY: BANDS OF MODERATE TO HEAVY RAIN AND IFR
CONDITIONS WILL MORE-OR-LESS CONTINUE THROUGH TUESDAY MORNING.
DIURNALLY DRIVEN SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE
TUESDAY AFTERNOON THROUGH LATE WEEK. EARLY MORNING STRATUS AND/OR
FOG (IFR TO LIFR) WILL BE LIKELY.
RAH WATCHES/WARNINGS/ADVISORIES
FLOOD WATCH FROM LATE TONIGHT THROUGH TUESDAY MORNING FOR
NCZ007>011-021>028-038>043-073>078-083>086-088-089.
SYNOPSIS...BADGETT
NEAR TERM...CBL
SHORT TERM...DANCO
LONG TERM...DANCO
AVIATION...CBL/BADGETT
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