659
FXUS62 KRAH 110700
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
300 AM EDT SUN MAY 11 2025
SYNOPSIS
HIGH PRESSURE WILL PUSH OFF THE MID ATLANTIC AND NORTHEAST COAST
TODAY. A SLOW MOVING UPPER LOW CENTERED OVER LOUISIANA THIS MORNING
WILL DRIFT NORTHEAST THROUGH THE MID SOUTH TO THE CENTRAL
APPALACHIANS THROUGH WEDNESDAY, BRINGING WET AND UNSETTLED WEATHER
TO THE CAROLINAS.
NEAR TERM /TODAY THROUGH TONIGHT/
AS OF 250 AM SUNDAY...
A CLOSED UPPER LOW CURRENTLY OVER THE SOUTHERN MISS VALLEY AND THE
MOIST DEEP SOUTHERLY FLOW ON ITS EAST SIDE WILL BE THE PRIMARY
INFLUENCE ON OUR WX TODAY. THE RAIN THAT'S CURRENTLY SEEN ON
REGIONAL RADAR TO OUR SOUTH IS PROGGED TO LIFT NORTHWARD THIS
MORNING REACHING OUR SOUTHERN PIEDMONT AND TRIAD ZONES SHORTLY AFTER
DAYBREAK, THEN CONTINUING TO LIFT NORTH REACHING THE TRIANGLE BY
EARLY AFTERNOON. AFTER A SEVERAL HOUR PERIOD OF MAINLY LIGHT RAIN
FALLING ACROSS AREAS TO THE SOUTH AND WEST OF RDU, NEARLY ALL
MEMBERS OF THE HREF SHOW THIS BAND OF RAIN DISSIPATING AS IT
CONTINUES TO MOVE NORTHWARD INTO A MUCH DRIER AND MORE STABLE
AIRMASS ASSOCIATED WITH HIGH PRESSURE TO OUR NORTH. HIGHS TODAY,
LARGELY INFLUENCED BY CLOUDS AND RAIN, WILL BE HELD IN THE UPPER 60S
ACROSS THE TRIAD AND LOWER 70S ELSEWHERE.
A LULL IN THE RAIN IS EXPECTED ACROSS MUCH OF CENTRAL NC THIS
EVENING AND EARLY OVERNIGHT BEFORE THE NEXT ROUND OF MORE VIGOROUS
RAIN BREAKS OUT DURING THE PRE-DAWN HOURS MONDAY MORNING ASSOCIATED
WITH A POWERFUL JET STREAK LIFTING NORTH ON THE DOWNWIND SIDE OF THE
UPPER TROUGH. LOWS TONIGHT IN THE UPPER 50S TO LOWER 60S.
SHORT TERM /MONDAY AND MONDAY NIGHT/
AS OF 300 AM SUNDAY...
* A FLASH FLOOD WATCH HAS BEEN ISSUED FOR ALL OF CENTRAL NC FROM
EARLY-MORNING MON THROUGH DAYBREAK TUE, DUE TO THE POTENTIAL FOR
ROUNDS OF MODERATE TO HEAVY RAIN.
LITTLE HAS CHANGED WITH THE OVERALL PATTERN AND EXPECTATIONS FROM
EARLIER FORECASTS. THE DEEP LOW CENTERED OVER LA/MS EARLY MON IS
EXPECTED TO OPEN A BIT AND LIFT NNE INTO W TN/W KY THROUGH EARLY
TUE, AS THE TRAILING NEGATIVELY TILTED MID LEVEL TROUGH AND SURFACE
FRONT LIFT NE THROUGH GA AND THE WESTERN CAROLINAS. THE COMBINATION
OF DEEP AND PLENTIFUL MOISTURE AND ROUNDS OF FORCING FOR ASCENT
CONTINUE TO FAVOR A RISK FOR AREAS OF HEAVY RAIN TOTALS. THESE
INGREDIENTS INCLUDE A PLUME OF 1.5-1.8" PWS (~160% OF NORMAL) THAT
WILL SPREAD NORTHWARD ON THE E SIDE OF THE LOW THROUGH CENTRAL NC
STARTING LATE TONIGHT, SHIFTING INTO E NC LATE MON NIGHT, WITHIN A
LONG LOW-LEVEL SE FETCH OF ATLANTIC MOISTURE ON THE SW SIDE OF THE
EXITING HIGH, AND WITH CONTRIBUTIONS FROM GULF-SOURCE MOISTURE IN
MORE SOUTHERLY FLOW JUST ALOFT. WARM RAIN PROCESSES ARE FAVORED,
WITH PROJECTED LCL-0C DEPTH OF 11K-12K FT AMIDST A STREAM OF
ELEVATED INTEGRATED VAPOR TRANSPORT. WHILE IT WON'T BE RAINING
HEAVILY ALL OF THIS TIME, THERE MAY BE AT LEAST TWO MAIN WINDOWS OF
GREATER POTENTIAL WHERE FORCING WILL BE FOCUSED, INCLUDING EARLY MON
MORNING DUE TO A SURGE IN DEEP MOIST ISENTROPIC UPGLIDE, AND MON
EVENING/NIGHT DUE TO AN INCREASE IN UPPER DIVERGENCE IN THE EXIT
REGION OF THE SOUTHERLY UPPER JET. FORECAST TOTAL RAINFALL FROM
TODAY THROUGH MON NIGHT HAS ACTUALLY RISEN A BIT SINCE YESTERDAY,
WHICH COULD BE A RESPONSE TO DATA ASSIMILATION OF CURRENT RAINFALL
TO OUR S AND/OR INCLUSION OF RAINFALL FROM CONVECTION-ALLOWING
MODELS, AS WE'RE STARTING TO GET WITHIN THEIR TIME FRAME. THE LATEST
WPC SUPERENSEMBLE QPF PLUMES ARE OVERALL AROUND 1/2 INCH HIGHER WITH
TOTAL QPF THAN YESTERDAY'S OUTPUT. WE'RE MOST LIKELY TO SEE 2-4
INCHES OF RAIN THROUGH EARLY TUE, ALTHOUGH THE LATEST ENSEMBLE
PROBABILITIES GIVE A 10% CHANCE OF UP TO 5 INCHES IN SPOTS. THIS
COULD PRODUCE LOCALIZED FLOODING, ESP IN URBAN AREAS, WITH RISES ON
CREEKS AND STREAMS POSSIBLE, ALL SUPPORTING THE FLASH FLOOD WATCH
ISSUANCE. WITH ABUNDANT THICK CLOUDS AND MINIMAL INSOLATION, EXPECT
A TIGHTER DIURNAL TEMP RANGE, WITH HIGHS IN THE UPPER 60S TO MID 70S
FOLLOWED BY LOWS IN THE 60S. -GIH
LONG TERM /MONDAY THROUGH SATURDAY/
AS OF 200 PM SATURDAY...
* PERIODS OF MODERATE TO HEAVY RAINFALL EXPECTED MON THROUGH TUE
NIGHT, WITH TOTALS RANGING FROM 2-4 INCHES. A FLOOD WATCH MAY BE
NEEDED IN LATER FORECAST UPDATES
* TRENDING HOT WITH MORE DIURNAL SHOWERS/STORMS THU THRU SAT
NOT MUCH HAS CHANGED REGARDING SPECIFICS FOR WHAT HAS BEEN
ADVERTISED FOR SEVERAL DAYS NOW REGARDING THE SYSTEM FOR THE EARLY
TO MIDDLE OF NEXT WEEK. A CLOSED UPPER LOW WILL SLOWLY TRACK FROM
THE LOWER MS VALLEY MON INTO THE TN VALLEY TUE AND SOUTHERN
APPALACHIANS TO MID-ATLANTIC WED AND WED NIGHT. ENSEMBLE CLUSTER
SOLUTIONS TAKE THE SYSTEM OFF THE EAST COAST SOMETIME THU, WITH
RIDGING BUILDING IN FRI AHEAD OF ANOTHER POTENTIAL FRONTAL SYSTEM ON
SAT.
AS THE AFOREMENTIONED SYSTEM MOVES TOWARD THE ENE INTO MIDWEEK, A
NUMBER OF INGREDIENTS WILL COME TOGETHER FOR PERIODS OF MODERATE TO
HEAVY RAINFALL WITH EMBEDDED STORMS. THESE INGREDIENTS INCLUDE
PRECIPITABLE WATER VALUES (1.75+ INCHES) AND MOISTURE TRANSPORT
VALUES (500 TO 750 KG M/S) NEAR THE 99TH PERCENTILE FOR THIS TIME OF
YEAR, DIFFLUENT FLOW AND DIVERGENCE FROM THE LEFT EXIT REGION OF A
JET STREAK, AND INSTABILITY. FORECAST SOUNDINGS ALSO INDICATE
POTENTIAL TRAINING STORMS WITH DEEP WARM CLOUD DEPTHS FOR FLOODING
POTENTIAL. FORECAST QPF AMOUNTS ARE STILL EXPECTED TO RANGE FROM 2
TO 4 INCHES, LOWEST NE AND HIGHEST SW. THE LOW-END (AT LEAST THIS
MUCH) RANGES FROM 1.5 TO 2.5 INCHES. BUT GIVEN THE ANOMALOUS
MOISTURE, AMOUNTS COULD BE NEAR THE 75-90TH PERCENTILE IN SOME
SPOTS, WHICH RANGES 3 TO 5 INCHES.
A FLOOD WATCH MAY BE NEEDED FOR THE PERIOD MON THROUGH TUE NIGHT.
THE GEFS/NAEFS INDICATE A 30-PERCENT CHANCE OF ACTION TO MINOR FLOOD
STAGE OF PART OF THE ROCKY RIVER, DEEP AND HAW RIVERS, AND PART OF
THE NEUSE BETWEEN TUE AND THU. A SLIGHT RISK OF EXCESSIVE RAINFALL
REMAINS IN EFFECT. THE HEAVIEST RAINFALL IS FAVORED MON AFTN THROUGH
TUE EVENING WHEN THE SAID INGREDIENTS ARE MORE ALIGNED. THE HIGH
RAIN CHANCES SHOULD KEEP TEMPERATURES BELOW NORMAL IN THE LOW/MID
70S MON AND MID 70S TO LOW 80S TUE. LASTLY, WE CANNOT RULE OUT AN
ISOLATED SEVERE THREAT TUE WITH MARGINAL SHEAR IN PLACE.
BY WED, THE SYSTEM BECOMES MORE BAGGY JUST TO OUR NORTH, BUT A
SURFACE LOW MOVING THROUGH COMBINED WITH DAYTIME INSTABILITY UNDER
COLD AIR ALOFT SHOULD FAVOR AFTN/EVE SCATTERED SHOWERS/STORMS, SOME
OF WHICH MAY BE SEVERE. HIGHS SHOULD BE WARMER IN THE UPPER 70S TO
MID 80S.
THE PATTERN THU THROUGH SAT SHOULD FAVOR MORE DIURNALLY DRIVEN
SHOWER AND STORM CHANCES NEAR THE 20-40 PERCENT CHANCE RANGE UNDER
SHORTWAVE ENERGY FRI AND A POSSIBLE FRONT SAT. HIGHS SHOULD ALSO
TREND ABOVE NORMAL TO NEAR HOT CONDITIONS WITH MID/UPPER 80S THU TO
UPPER 80S TO LOW 90S FRI/SAT. THERE COULD BE SOME HIGH HEAT INDICES
AS WELL GIVEN DEWPOINTS EXPECTED TO BE IN THE MID/UPPER 60S.
AVIATION /06Z SUNDAY THROUGH THURSDAY/
AS OF 250 AM SUNDAY...
THROUGH 06Z MONDAY: MVFR CONDITIONS ARE GRADUALLY LIFTING NORTHWARD
TOWARD CENTRAL NC FROM THE SOUTH AND WILL EXIST OFF-AND-ON
THROUGHOUT THE DAYTIME TODAY MAINLY FROM RDU SOUTH AND WESTWARD.
WITH THE EXCEPTION OF KRWI, FLT CONDITIONS MAY DROP TO LOW-MVFR OR
IFR AT TIMES AS A BAND OF RAIN, CURRENTLY SEEN ON RADAR LIFTING
NORTH ACROSS SC, MAKES ITS WAY UP TO CENTRAL NC DURING THE MORNING
AND AFTERNOON HOURS. CIGS ARE THEN EXPECTED TO DROP TO IFR CRITERIA
AFTER SUNSET AND REMAIN THROUGH THE REST OF THE NIGHT.
AFTER 06Z MONDAY: WIDESPREAD MODERATE TO HEAVY RAIN AND IFR
CONDITIONS ARE FORECAST MONDAY THROUGH TUESDAY MORNING. SCATTERED TO
NUMEROUS SHOWERS/STORMS WILL REMAIN POSSIBLE EACH AFTERNOON THROUGH
AT LEAST WEDNESDAY WITH THE THREAT FOR OVERNIGHT SUB-VFR FOG/STRATUS
THROUGH WEDNESDAY NIGHT.
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...HARTFIELD
NEAR TERM...NP
SHORT TERM...HARTFIELD
LONG TERM...KREN
AVIATION...NP
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