236
FXUS62 KRAH 201829
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
228 PM EDT SUN APR 20 2025
SYNOPSIS
A BACKDOOR COLD FRONT WILL SAG SLOWLY SOUTHWESTWARD ACROSS NORTHERN
NORTH CAROLINA THROUGH THIS EVENING, WHERE IT WILL BECOME QUASI-
STATIONARY THROUGH MONDAY MORNING. IT WILL THEN RETURN NORTH INTO
THE MIDDLE ATLANTIC AS A WARM FRONT DURING THE DAY MONDAY. A SLOW-
MOVING AND WEAKENING COLD FRONT WILL MOVE EAST INTO THE CAROLINAS
MONDAY NIGHT AND TUESDAY AND STALL ACROSS THE REGION THROUGH MUCH OF
THE WORK WEEK.
NEAR TERM /THROUGH TONIGHT/
AS OF 1100 AM SUNDAY...
THE PREVIOUS FORECAST AND RATIONALE ARE ON TRACK; AND NO GRIDDED
FORECAST CHANGES WERE NEEDED THIS MORNING. THE BACKDOOR COLD FRONT
WAS OVER FAR SRN VA (NEAR BLACKSTONE) AND NERN NC (NEAR ECG) AT
1445Z AND WILL CONTINUE TO DRIFT SWWD INTO THE FAR NE NC PIEDMONT
AND NRN COASTAL PLAIN THROUGH LATE AFTERNOON-EARLY EVENING.
PREV DISCUSSION
/ISSUED 345 AM EDT SUN APR 20 2025/
* CONTINUED UNSEASONABLY WARM
ALOFT, THE MID-LEVEL ANTICYCLONE WILL REMAIN OVER/JUST OFF THE
SOUTHEAST US COAST, RIDGING NWD ALONG THE CAROLINA/SRN MID-ATLANTIC
COAST, THROUGH TONIGHT. MEANWHILE, THE H5 LOW (OVER NM AS OF 06Z)
WILL SHIFT EWD INTO THE SRN PLAINS THIS MORNING, THEN LIFT NNEWD
ACROSS THE CNTL PLAINS AND INTO THE UPPER MS VALLEY THROUGH TONIGHT.
AT THE SURFACE, A BACKDOOR COLD FRONT WILL SLIDE SWD ACROSS THE MID-
ATLANTIC AND INTO NORTHEAST NC THROUGH THIS EVENING, THEN STALL OVER
THE COASTAL PLAIN AND NRN PIEDMONT TONIGHT. MEANWHILE, THE BERMUDA
HIGH WILL RETREAT WWD TOWARD THE SOUTHEAST US COAST AS THE CANADIAN
HIGH CONTINUES EWD ACROSS SRN ONTARIO, QUEBEC, AND THE NORTHEAST US
TODAY INTO TONIGHT, THE BACKDOOR FRONT SITUATED BETWEEN THE TWO
HIGHS. STILL EXPECT AN AREA OF MOISTURE CONVERGENCE ALONG THE
BACKDOOR FRONT, WITH LOCALIZED DEWPOINTS TEMPS IN THE LOW TO MID
60S. FORECAST SOUNDINGS DO SHOW SOME MLCAPE (HIGHEST (~1000 J/KG)
OFF THE NAM AT KRDU AND KRWI), HOWEVER MUCH OF THAT INSTABILITY
RESIDES ABOVE A CAPPING INVERSION, WHICH FOR NOW SEEMS TO HOLD. WITH
THE MOISTURE AND INSTABILITY PRESENT, CANNOT RULE OUT A STRAY SHOWER
ALONG THE FRONT, BUT CHANCES REMAIN LOW AT THIS TIME. SKIES SHOULD
GENERALLY REMAIN CLOUDY TODAY AND TONIGHT, HOWEVER HIGHS SHOULD
STILL BE SIMILAR TO SAT, IN THE MID 80S. LOWS TONIGHT WILL BE
CONTINUED MILD, UPPER 50S TO LOW 60S. THERE COULD BE A BRIEF PERIOD
OF SOME GUSTS OF 15-20 MPH ALONG AND IN THE WAKE OF THE FRONT THIS
EVENING, OTHERWISE EXPECT WINDS OF 5-10 KTS, GENERALLY SWLY TO
SSELY.
SHORT TERM /MONDAY AND MONDAY NIGHT/
AS OF 111 PM SUNDAY...
* ABOVE AVERAGE TEMPERATURES EXPECTED AGAIN ON MONDAY.
* RAIN COULD START AS EARLY AS LATE OVERNIGHT/EARLY TUESDAY MORNING
AHEAD OF AN APPROACHING COLD FRONT.
MONDAY WE WILL BE UNDER THE INFLUENCE OF DEEP SOUTHERLY FLOW AS THE
THE SURFACE HIGH TO OUR SOUTHEAST WEAKENS OFFSHORE AND THE NEXT COLD
FRONT APPROACHES THE REGION FROM THE WEST. THIS WILL KEEP MAXIMUM
TEMPERATURES ABOUT 10 DEGREES ABOVE AVERAGE, WITH HIGHS EXPECTED IN
THE LOW TO MID 80S. MINIMUM TEMPERATURES SHOULD BE ABOUT 15 DEGREES
ABOVE NORMAL, WITH LOWS IN THE LOW TO MID 60S. AS THE FRONT
APPROACHES, THE PRESSURE GRADIENT WILL TIGHTEN OVER THE REGION. THIS
WILL ALLOW THE WINDS TO GUST UP TO AROUND 20-25 MPH. IN TERMS OF
PRECIPITATION, RAIN WILL HOLD OFF DURING THE DAY ON MONDAY. SHOWERS
MAY REACH THE TRIAD VERY LATE MONDAY NIGHT OR EARLY TUESDAY MORNING
AS THE FRONT APPROACHES THE REGION. LOOKING AT THE ENSEMBLE MEAN 6
HOUR PRECIP CHANCES, ONLY THE GEFS HAS RAIN CHANCES IN THE TRIAD
BEFORE 12Z, SO KEPT SLIGHT CHANCE POPS UNTIL 12Z.
LONG TERM /TUESDAY THROUGH SUNDAY/
AS OF 228 PM SUNDAY...
THE MID-LEVEL RIDGE WILL BEGIN TO BREAKDOWN MONDAY INTO TUESDAY, AS
A STRONG UPPER TROUGH LIFTS THROUGH THE GREAT LAKES REGION. A SERIES
OF WEAK SHORT-WAVES WILL TRAVERSE OVERHEAD THE REST OF THE WEEK.
MODELS HINT AT ANOTHER GREAT LAKES TROUGH AND ASSOCIATED EMBEDDED
MID-LEVEL PERTURBATIONS ADVECTING ACROSS THE EASTERN SEABOARD FRIDAY
INTO THE WEEKEND.
WHILE THE STRONG UPPER FORCING WILL GENERALLY REMAIN WELL NORTH OF
OUR AREA TUESDAY, SFC CONVERGENCE ALONG AN ADVANCING FRONT, COMBINED
WITH INCREASING MOISTURE FLUX WILL PROMOTE SHOWER/THUNDERSTORM
CHANCES ACROSS CENTRAL NC. EXPECT A DIURNAL MAXIMA IN SHOWERS/TSTORM
COVERAGE WITH HIGHEST POPS TUESDAY AFTERNOON. BULK-LAYER SHEAR WILL
GENERALLY TREND DOWNWARDS WITH TIME TUESDAY, BUT SOME AFTERNOON
LINGERING SHEAR OF 25 TO 35 KTS COULD COINCIDE WITH THE DIURNAL
MAXIMA OF TSTORMS TO PROMOTE PERHAPS A STRONGER STORM OR TWO. THIS
IS APPEARS MOST LIKELY FOR AREAS ALONG THE NC/SC BORDER (THE CSU ML
PRODUCT HIGHLIGHTS LOW SEVERE WEATHER PROBABILITIES IN THIS
VICINITY).
ANOMALOUS MOISTURE WILL LINGER THROUGH THE REST OF THE EXTENDED, AS
THE SFC FRONT SHIFTS SOUTH OF US, STALLS, AND THE RIDES NORTH AS A
WARM FRONT BY FRIDAY. WEAK PERTURBATIONS WILL TRAVERSE OVERHEAD EACH
DAY, PROMOTING CONTINUED DIURNAL CHANCES FOR SHOWERS AND STORMS EACH
DAY. A FEW STRONGER STORMS COULD BE POSSIBLE WEDNESDAY
AFTERNOON/EVENING AS A WEAK SHORT-WAVE AND ASSOCIATED POCKET OF
MODERATELY STRONGER SHEAR MOVES OVER. OTHERWISE, SEVERE WEATHER IS
NOT EXPECTED THROUGH AT LEAST FRIDAY.
AS THE NEXT TROUGH EJECTS ACROSS THE GREAT LAKES, A BIT BETTER
SHEAR/UPPER FORCING MAY EXTEND SOUTH OVER CENTRAL NC ON SATURDAY AND
SUNDAY. AS SUCH, SOME STRONGER STORMS MAY BE POSSIBLE THIS UPCOMING
WEEKEND. ENSEMBLE (GEPS/GEFS/ENS) RUN TOTAL PRECIPITATION FROM
TUESDAY THROUGH SUNDAY INDICATES ANYWHERE FROM A HALF INCH TO THREE
QUARTERS OF AN INCH (10TH TO 25TH PERCENTILE) TO 1.5 TO 2.5 INCHES
(75TH TO 90TH PERCENTILE). WPC CURRENTLY HIGHLIGHTS ANYWHERE FROM
0.75 TO 1.5 INCHES THROUGH THE SAME PERIOD. AS SUCH, FOR NOW, NOT
OVERLY CONCERNED WITH ANY FLOODING THREATS.
TEMPERATURES WILL BE WARM OVER THIS PERIOD, GENERALLY IN THE LOWER
TO MID 80S, WITH PERHAPS SOME RELATIVE REPRIEVE INTO THE UPPER 70S
ACROSS THE NC/VA BORDER.
AVIATION /18Z SUNDAY THROUGH FRIDAY/
AS OF 215 PM SUNDAY...
INFLUENCED BY SUB-TROPICAL HIGH PRESSURE OFF THE SOUTH ATLANTIC
COAST, PRIMARILY VFR CONDITIONS ARE EXPECTED THROUGH THE FORECAST
PERIOD. THE EXCEPTION TO VFR WILL BE THE PROBABLE OCCURRENCE OF IFR-
MVFR CEILINGS AT RWI LATE TONIGHT-MON MORNING, IN THE WAKE OF A
BACKDOOR COLD FRONT THAT WILL SETTLE SWWD ACROSS THE NE PIEDMONT AND
NRN THROUGH CNTL COASTAL PLAIN OF NC THROUGH THIS EVENING. A SEVERAL
HOUR PERIOD OF ELY SURFACE WINDS UP TO 15-20 KTS IN GUSTS WILL ALSO
BE POSSIBLE IMMEDIATELY FOLLOWING THE PASSAGE OF THE FRONT, WHICH
WILL ALSO BE MOST LIKELY AT RWI, AND WITH LESSER CONFIDENCE AT RDU,
EARLY TONIGHT.
OUTLOOK: A FRONT WILL SETTLE INTO AND BECOME QUASI-STATIONARY OVER
NC, WITH AN ASSOCIATED CHANCE OF CONVECTION AND FLIGHT RESTRICTIONS,
TUE-THU.
CLIMATE
RECORD HIGH TEMPERATURES:
APRIL 20:
KGSO: 94/1917
KRDU: 93/1896
KFAY: 94/1917
RECORD HIGH MINIMUM TEMPERATURES:
APRIL 20:
KGSO: 65/1941
KRDU: 67/1896
KFAY: 69/2011
APRIL 21:
KGSO: 64/1927
KRDU: 70/1896
KFAY: 68/2017
APRIL 22:
KGSO: 63/1967
KRDU: 66/1909
KFAY: 64/1963
RAH WATCHES/WARNINGS/ADVISORIES
NONE.
SYNOPSIS...MWS/BLAES
NEAR TERM...MWS/KC
SHORT TERM...HELOCK
LONG TERM...LUCHETTI
AVIATION...MWS
CLIMATE...RAH
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