386
FXUS62 KRAH 101757
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
200 PM EDT SAT MAY 10 2025
SYNOPSIS
COOL HIGH PRESSURE WILL BUILD IN FROM THE NORTHWEST AND NORTH TODAY.
A SLOW MOVING UPPER LOW OVER THE CENTRAL GULF COAST WILL DRIFT
NORTHEAST SUNDAY THROUGH TUESDAY, BRINGING WET AND UNSETTLED WEATHER
TO THE CAROLINAS.
NEAR TERM /TODAY AND TONIGHT/
AS OF 910 AM SATURDAY...
WHILE THERE IS A GOOD AMOUNT OF CIRRUS ACROSS THE AREA, NO AUTOMATED
STATIONS ARE REPORTING ANY CLOUDS BELOW 12,000 FT. WITH THE MORNING
UPDATE, MADE SOME MINIMAL ADJUSTMENTS TO HOURLY TEMPERATURES AND THE
ARRIVAL TIMES OF PRECIPITATION ACROSS SOUTHERN COUNTIES LATE THIS
AFTERNOON. STILL THINK VIRTUALLY PRECIPITATION WILL HOLD OFF ACROSS
CENTRAL NORTH CAROLINA UNTIL AFTER SUNSET. PREVIOUS DISCUSSION
FOLLOWS.
AS OF 300 AM SATURDAY...
HIGH PRESSURE WILL BRIEFLY BUILD ACROSS OUR AREA TODAY BEHIND THE
COLD FRONT THAT MOVED ACROSS THE AREA A COUPLE HOURS AGO. SFC WINDS
ARE NOW NE AND THAT'S ADVECTING IN COOLER AND NOTABLY DRIER AIR AS
DEMONSTRATED BY THE DWPT DROP THAT HAS OCCURRED THE PAST FEW HOURS.
THAT WILL SET US UP FOR A FAIR WEATHER DAY TODAY WITH COMFORTABLE
TEMPS AND HUMIDITY, ALBEIT SOMEWHAT CLOUDY AT TIMES WITH AN AMPLE
STREAM OF CIRRUS MOVING ACROSS OUR AREA... THAT CIRRUS OCCURRING OUT
AHEAD OF THE CLOSED UPPER LOW THAT'S CENTERED OVER THE SOUTHERN MISS
VALLEY. HIGHS TODAY WILL RANGE FROM 71 TO 76, WITH COOLEST READINGS
NORTH NEAR THE VA BORDER.
FOR TONIGHT, A JET STREAK ROUNDING THE BASE OF THE AFOREMENTIONED
UPPER CLOSED LOW WILL INCREASE THE DEEP LAYER MOIST SOUTHERLY FLOW
ON THE EAST SIDE OF THE LOW, INCLUDING OVER THE CAROLINAS, THUS
RESULTING IN INCREASING AND LOWERING CLOUDS FROM SOUTH TO NORTH
ACROSS THE REGION. THIS MOIST SOUTHERLY FLOW WILL OVERRUN THE
ANTECEDENT COOLER AIRMASS, THUS RESULTING IN RAPIDLY INCREASING
ASCENT CENTERED BETWEEN H6 AND H9 BEGINNING AFTER 06Z TONIGHT. AS
SUCH, WILL INTRODUCE AND INCREASE POPS FROM SOUTH TO NORTH DURING
THE OVERNIGHT PERIOD, WITH THE EXCEPTION BEING OUR FAR N/NE ZONES
WHERE THE ARRIVAL OF THE AFOREMENTIONED WILL LIKELY OCCUR AFTER
DAYBREAK SUNDAY. MODEST LAPSE RATES SUGGEST MOSTLY A LIGHT RAIN
SETUP WITH QPF VALUES <1/4 INCH WHERE IT DOES RAIN OVERNIGHT.
LOWS IN THE 50S.
SHORT TERM /SUNDAY AND SUNDAY NIGHT/
AS OF 200 AM SATURDAY...
STILL EXPECT RAIN CHANCES TO RAMP UP, ESP ACROSS THE S, AS SURFACE
HIGH PRESSURE RIDGE CENTERED OVER THE ST LAWRENCE VALLEY AND
EXTENDING DOWN THE MID ATLANTIC COAST EARLY SUN SHIFTS E OVER AND
OFF NEW ENGLAND BY SUN NIGHT. THE MID LEVEL LOW CENTERED OVER LA
WILL MOVES LITTLE OVERALL THROUGH SUN NIGHT, ALTHOUGH THE MID LEVEL
SOUTHERLY FLOW TO ITS E WILL INCREASE, WITH STRENGTHENING MOISTURE
FLUX AND SHOTS OF DPVA - PERHAPS INCLUDING MCVS FROM GULF CONVECTION
- BEING DRAWN OUT OF THE N GULF INTO THE CAROLINAS. PREVIOUS MODEL
RUNS IN THE LAST FEW DAYS HAVE VARIED WITH HOW FAR N TO BRING THE
RAIN SHIELD SUN/SUN NIGHT, BUT MORE RECENT DETERMINISTIC MODELS AND
ENSEMBLE OUTPUT ARE TRENDING TOWARD GREATER WATER VAPOR TRANSPORT
AND MORE COLUMN MOISTENING AND LIFT, POINT TO A QUICKER RAIN
ARRIVAL, ESP ACROSS OUR S AND MOST MARKEDLY SUN EVENING/NIGHT. HIGH
PWS WILL SPREAD IN FROM THE S SUN THROUGH SUN NIGHT, REACHING VALUES
OF 1.5-1.8" OR ~150% OF NORMAL. WHILE NORTHERN SECTIONS OF THE CWA
SHOULD STILL BE MOSTLY DRY SUN WITH A DEEPER/DRIER SUBCLOUD LAYER
CLOSER TO THE DEPARTING SURFACE HIGH, LOW/LIGHT POPS MAY STILL BE
WARRANTED INTO AREAS N OF HWY 64, ESP IN THE TRIAD, AS 290K-305K
MOIST UPGLIDE STRENGTHENS AND DEEPENS. OVERALL, PRECIP SUN SHOULD BE
FAIRLY LIGHT GIVEN THE ILL-DEFINED FORCING FOR ASCENT INCLUDING
INITIALLY MUTED MOIST UPGLIDE, BUT RAIN RATES ARE LIKELY TO PICK UP
ESP ACROSS OUR FAR S AND W SUN NIGHT AS LOW LEVEL WINDS STRENGTHEN,
IN PART A FUNCTION OF TIGHTENING MSLP GRADIENT AS THE SURFACE HIGH
SETTLES OFF THE NEW ENGLAND COAST, RESULTING IN AN INCREASE IN MOIST
UPGLIDE AND STRENGTHENING OF A LONG MOIST ATLANTIC FETCH. BELOW
NORMAL HIGHS ARE LIKELY WITH CLOUDY SKIES, MAINLY UPPER 60S TO LOW
70S, WITH THE NE CWA THE WARMEST AND THE S AND SW COOLER. MILD LOWS
IN THE MID 50S TO LOW 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 /18Z SATURDAY THROUGH THURSDAY/
AS OF 120 PM SATURDAY...
TAF PERIOD: MOST OF THE NEXT 24 HOURS WILL HAVE VFR CONDITIONS. A
STACKED UPPER LEVEL AND SURFACE LOW WILL REMAIN NEARLY STATIONARY
OVER LOUISIANA INTO SUNDAY AFTERNOON. AS A JET STREAK BRINGS
ADDITIONAL MOISTURE INTO THE REGION, HIGH CLOUDS WILL INCREASE IN
COVERAGE THROUGH THE AFTERNOON AND LOWER IN HEIGHT OVERNIGHT.
CONFIDENCE IS HIGH THAT FAY WILL DROP TO MVFR CONDITIONS AROUND
SUNRISE ON SUNDAY, WITH LESS CONFIDENCE IN HOW MUCH SHOWER COVERAGE
WILL BE AROUND THE AREA. WILL KEEP THE INHERITED VCSH MENTION IN AT
FAY. IT APPEARS THAT BY 18Z SUNDAY, INT/GSO WILL BE APPROACHING MVFR
CIGS AND FAY WILL BE APPROACHING IFR CIGS, BUT THAT TIMING CAN BE
BETTER HANDLED IN THE 00Z TAF PACKAGE.
OUTLOOK: RAIN WILL INCREASE IN COVERAGE SUNDAY AFTERNOON AND NIGHT,
WITH WIDESPREAD MODERATE TO HEAVY RAIN AND IFR CONDITIONS FORECAST
MONDAY THROUGH WEDNESDAY. SOME DIURNAL SHOWERS WILL CONTINUE ON
THURSDAY.
RAH WATCHES/WARNINGS/ADVISORIES
NONE.
SYNOPSIS...NP
NEAR TERM...GREEN/NP
SHORT TERM...HARTFIELD
LONG TERM...KREN
AVIATION...GREEN
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