780
FXUS62 KRAH 201826
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
226 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 SATURDAY/
AS OF 310 AM SUNDAY...
* HIGH TEMPERATURES WILL BE WELL ABOVE NORMAL ON TUESDAY AND
SLIGHTLY ABOVE NORMAL FOR THE REST OF THE PERIOD.
* A WEAKENING FRONT WILL MOVE INTO THE AREA ON TUESDAY AND LINGER
FOR MUCH OF THE WORK WEEK PROVIDING A WEAK FOCUS FOR SCATTERED
SHOWERS AND A FEW STORMS.
* RAINFALL TOTALS FOR TUESDAY THROUGH SATURDAY WILL AVERAGE AROUND A
HALF INCH WITH SOMEWHAT GREATER AMOUNTS ACROSS SOUTHERN AREAS.
THE LONG TERM PERIOD BEGINS ON TUESDAY MORNING WITH AN EXITING MID
AND UPPER-LEVEL CLOSED LOW ACROSS QUEBEC AND A WEAKENED RIDGE JUST
EAST OF FL. THE REMNANTS OF A SHEARED OUT TROUGH WILL EXTEND FROM
THE CHESAPEAKE BAY SOUTHWEST ACROSS THE WESTERN CAROLINAS INTO THE
DEEP SOUTH. AN ASSOCIATED SURFACE COLD FRONT WHICH WILL BE WEAKENING
DROPS INTO THE WESTERN CAROLINAS MONDAY NIGHT AND MOVES INTO THE
CENTRAL CAROLINAS ON TUESDAY AND WEDNESDAY AND THEN WAIVERS AND
DISSIPATES ON THURSDAY AND FRIDAY.
DEEP LAYER MOISTURE WILL INCREASE WITH THE SOUTHWESTERLY FLOW ALOFT
RESULTING IN PW VALUES INCREASING TO AROUND 1.5 INCHES ACROSS
CENTRAL NC LATE TUESDAY AND INTO WEDNESDAY. THE ENHANCED MOISTURE
PERSISTS AND MAY MOISTEN FURTHER ON THURSDAY AND FRIDAY. WHILE THE
FORCING WON'T BE PARTICULARLY STRONG, LOW-LEVEL CONVERGENCE ALONG
THE FRONT, INCREASING MOISTURE, AND SOME MODEST LOW LEVEL
INSTABILITY WILL SUPPORT SHOWER/THUNDERSTORM CHANCES ACROSS CENTRAL
NC FOR THE TUESDAY THROUGH FRIDAY PERIOD. THE GREATEST POPS IN THE
50% RANGE ARE FOCUSED ON WEDNESDAY AND PERHAPS THURSDAY WITH THE
PRECIPITATION CHANCES GREATEST DURING THE AFTERNOON AND EVENING. A
SLIGHT ENHANCEMENT TO THE MID LEVEL FLOW WILL SUPPORT BULK-LAYER
SHEAR VALUES OF 20 TO 30 KTS MAINLY FOR WEDNESDAY THROUGH FRIDAY
WHICH COULD RESULT IN A STRONGER STORM OR TWO BUT NO WIDESPREAD
ORGANIZED SEVERE WEATHER IS EXPECTED DURING THE PERIOD. RAINFALL
TOTALS THROUGH FRIDAY NIGHT WILL AVERAGE AROUND A HALF INCH WITH
SLIGHTLY GREATER AMOUNTS PROBABLE ACROSS SOUTHERN AREAS IN THE
SOUTHERN PIEDMONT AND SANDHILLS WHERE GREATER INSTABILITY AND
MOISTURE IS EXPECTED.
HIGH TEMPERATURES WILL BE THE WARMEST ON TUESDAY WITH HIGHS IN THE
LOWER TO MID 80S WHICH IS ABOUT 8 TO 12 DEGREES ABOVE AVERAGE. HIGHS
WILL DROP BACK A BIT ON WEDNESDAY AND THURSDAY AND RANGE IN THE
UPPER 70S TO LOWER 80S WHICH IS ABOUT 4 TO 8 DEGREES ABOVE AVERAGE.
LOWS WILL RANGE MAINLY IN THE UPPER 50S TO LOWER 60S.
THE NEXT MID AND UPPER LEVEL TROUGH DEVELOPS ACROSS THE MIDWEST AND
GREAT LAKES ON FRIDAY AND APPROACHES THE CAROLINAS ON SATURDAY. AN
ASSOCIATED COLD FRONT WILL ALSO APPROACH THE AREA WITH ENHANCED
MOISTURE AND SOME STRONGER FLOW WHICH WILL SUPPORT AN UPTICK IN
SHOWER AND STORM COVERAGE. HIGHS WILL NUDGE UPWARD AHEAD OF THE
FRONT AND RANGE IN THE LOWER TO MID 80S ON SATURDAY. -BLAES
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...BLAES
AVIATION...MWS
CLIMATE...RAH
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