943
FXUS62 KRAH 101311
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
910 AM 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 FRIDAY/
AS OF 340 AM SATURDAY...
* STEADY MODERATE TO HEAVY RAINFALL REMAINS A GOOD POSSIBILITY EARLY
NEXT WEEK, PARTICULARLY MON THROUGH TUE NIGHT, WITH TOTALS UP TO 2-
4 INCHES, WHICH COULD GENERATE FLOODING.
* HOT WEATHER IS EXPECTED LATE IN THE UPCOMING WORK WEEK.
MON-TUE NIGHT: THE OVERALL PATTERN AS WELL AS THE EXPLICIT RAINFALL
PRODUCED BY THE DETERMINISTIC MODELS AND ENSEMBLE SYSTEMS STRONGLY
FAVOR PERIODS OF MODERATE TO HEAVY RAIN IN THIS TIME FRAME. THE DEEP
MID LEVEL LOW WILL LIFT SLOWLY NNE TO THE MID MISS VALLEY BY EARLY
TUE AND TO THE CENTRAL OHIO VALLEY BY EARLY WED MORNING, WHILE THE
TRAILING MID LEVEL TROUGH AND ATTENDANT SURFACE LOW AND FRONTAL
SYSTEM SHIFTS SLOWLY ENE INTO AND THROUGH THE SOUTHEAST. WITHIN HIGH
MOISTURE CONTENT THROUGH THE COLUMN, WAVES OF STRONGER FORCING FOR
ASCENT WILL INCLUDE PERIODIC DPVA RIDING UP FROM THE GULF COAST, AS
WELL AS INCREASING UPPER DIVERGENCE IN THE EXIT REGION OF THE JET
CORE LIFTING UP E OF THE TROUGH, THIS LATTER FORCING PEAKING FROM
LATE MON THROUGH EARLY TUE. OUR SATURATED ISENTROPIC UPGLIDE REMAINS
DEEP AND FAIRLY STRONG, ESP MON, CORRESPONDING TO A STREAM OF HIGH
PW UP TO 150-180% OF NORMAL. BASED ON THE EXPECTED NORTHWARD
MOVEMENT AND S-N ORIENTATION OF CONVECTIVE CELLS OR LINE SEGMENTS,
SUBSTANTIAL TRAINING IS POSSIBLE, WHICH COULD BOOST LOCAL RAINFALL
TOTALS. AND IF THE LOW LEVEL BACKING OF STRENGTHENING LOW LEVEL FLOW
TO SSE COMES TO PASS BY TUE AS THE MID LEVEL TROUGH APPROACHES WITH
A SLIGHTLY NEGATIVE TILT, RAINBANDS COULD BECOME ROUGHLY ORIENTED
ALONG OUR MAINSTEM RIVER BASINS, FAVORING A HIGHER RISK OF
SIGNIFICANT RISES ON RIVERS AND TRIBUTARIES. WITH LOTS OF THICK
CLOUDS AND PERIODS OF SHOWERS AND STORMS, TEMPS WILL EXHIBIT A
SMALLER THAN USUAL DIURNAL RANGE, WITH HIGHS IN THE UPPER 60S TO MID
70S MON AND 70S TUE, WHILE LOWS WILL BE IN THE 60S.
WED-FRI: RAIN CHANCES WILL REMAIN HIGH ACROSS OUR N AND E WED, AS
THE NEGATIVELY TILTED TROUGH LIFTS UP THROUGH THE AREA. HIGHS WILL
REMAIN SUPPRESSED A BIT BY CLOUDINESS AND SHOWERS, MID 70S TO LOW
80S. BY THU/FRI, A DEEP LOW TRACKS THROUGH THE ROCKIES INTO THE
DAKOTAS AND UPPER MIDWEST AND ALLOWS DOWNSTREAM MID LEVEL RIDGING TO
BUILD INTO THE CAROLINAS FROM THE WSW. AS WE GET FIRMLY IN THE WARM
SECTOR, OUR THICKNESSES WILL RISE TO 10 M ABOVE NORMAL THU AND 25 M
ABOVE NORMAL FRI, AS WE SEE A TREND TOWARD MORE TYPICAL SCATTERED
DIURNALLY-FAVORED CONVECTION. EXPECT HIGHS IN THE 80S THU AND UPPER
80S TO MID 90S FRI, WITH NEAR-CLIMO MAINLY AFTERNOON POPS. -GIH
AVIATION /12Z SATURDAY THROUGH WEDNESDAY/
AS OF 726 AM SATURDAY...
THROUGH 12Z SUNDAY: HIGH CLOUDS, BROKEN AT TIMES, AND VFR
CONDITIONS WILL BE THE CASE FOR MUCH OF THE TAF PERIOD. AFTER
MIDNIGHT LOCAL TIME, RAIN CHANCES AND SUB-VFR CONDITIONS WILL
INCREASE FROM SOUTH TO NORTH OVERNIGHT, YET VFR CONDITIONS MAY HOLD
ON UNTIL DAYBREAK SUNDAY NEAR THE VA BORDER. WINDS WILL GENERALLY
BE <10KTS.
OUTLOOK: ODDS FOR SUB-VFR CONDITIONS WILL INCREASE ON SUNDAY, AND
ESPECIALLY EARLY NEXT WEEK AS A WET PATTERN UNFOLDS ACROSS OUR AREA.
RAH WATCHES/WARNINGS/ADVISORIES
NONE.
SYNOPSIS...NP
NEAR TERM...GREEN/NP
SHORT TERM...HARTFIELD
LONG TERM...HARTFIELD
AVIATION...NP
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