196
FXUS62 KRAH 171118
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
620 AM EST SUN NOV 17 2024
SYNOPSIS
HIGH PRESSURE WILL REMAIN ACROSS THE MIDDLE AND SOUTH ATLANTIC
STATES THROUGH MONDAY, THEN MOVE OFFSHORE MONDAY NIGHT. A STRONG
COLD FRONT WILL MOVE THROUGH THE REGION MID-WEEK.
NEAR TERM /TONIGHT/
AS OF 212 AM SUNDAY...
FROST ADVISORY 400 AM THROUGH 800 AM TODAY.
MILD AND MAINLY SUNNY THIS AFTERNOON.
PATCHY FROST IS EXPECTED IN THE ADVISORY AREA MAINLY AWAY FROM URBAN
CENTERS. OTHERWISE, HIGH PRESSURE WILL EXTEND DOWN THE EASTERN
SEABOARD TODAY. THIS WILL BRING SUNNY SKIES AND MILD TEMPERATURES.
THE LATEST SATELLITE DATA INDICATED CLEAR SKIES WITH ONLY A PATCH OR
TWO OF HIGH THIN CIRRUS TO OUR WEST. EXPECT A FEW CIRRUS TODAY, BUT
OVERALL SUNNY SKIES. HIGHS ARE EXPECTED TO BE IN THE MID TO UPPER
60S (OR WITHIN A DEGREE OR TWO OF THE HIGHS SATURDAY).
MODELS SUGGEST A FEW MORE CIRRUS TONIGHT, BUT THE CIRRUS SHOULD
REMAIN RATHER THIN. LOWS WILL BE MILDER TONIGHT, BUT LIKELY A BIT
BELOW GUIDANCE GIVEN THE CALM AND MOSTLY CLEAR CONDITIONS EXPECTED.
LOWS 37-44.
SHORT TERM /MONDAY AND MONDAY NIGHT/
AS OF 212 AM SUNDAY...
ABOVE NORMAL TEMPERATURES RETURN MONDAY AND MONDAY NIGHT (TEMPS 5-10
DEGREES ABOVE NORMAL).
SURFACE HIGH PRESSURE WILL SLIDE JUST TO OUR SOUTH ON MONDAY. THE H5
RIDGE AXIS WILL REMAIN JUST WEST OF OUR REGION INTO MONDAY NIGHT.
ONLY A FEW HIGH CLOUDS ARE EXPECTED TO TOP THE RIDGE AXIS AT TIMES.
WITH RIDGING REMAINING OVERHEAD, EXPECT LIGHT AND VARIABLE WINDS
WITH PARTLY TO MOSTLY SUNNY SKIES. HIGHS WILL MODERATE INTO THE
LOWER 70S REGION WIDE. SKIES SHOULD BE PARTLY CLOUDY MONDAY NIGHT
WITH LOWS IN THE 43-48 RANGE.
LONG TERM /TUESDAY THROUGH SATURDAY/
AS OF 238 AM SUNDAY...
RIDGING OVER THE AREA TUE AND WED AHEAD OF A STRONG TROUGH TRACKING
INTO THE OH VALLEY WILL SPELL OUT MILD HIGHS TO START THE EXTENDED.
HIGHS ON TUE AND WED ARE STILL PROGGED TO BE IN THE UPPER 60S TO LOW
70S, ABOUT 8-10 DEGREES ABOVE NORMAL.
WE CONTINUE TO WATCH FOR THE CHANCE OF PRECIPITATION IN THE LATE TUE
THROUGH WED TIME FRAME. MOST DETERMINISTIC AND ENSEMBLE GUIDANCE
SHOWS LIGHT BUT MEASURABLE RAINFALL TUE NIGHT AS DEEP MOISTURE FROM
REMNANT TC SARA ADVECTS INTO THE SE US. PW'S REACH OVER 250-PERCENT
OF NORMAL AROUND 1.5 INCHES DURING THIS TIME. LIFT IS NOT OVERLY
IMPRESSIVE, DRIVEN LARGELY BY SOME WEAK ISENTROPIC ASCENT IN THE 700-
500 MB LAYER. THE PRIOR GEFS WAS A DRIER OUTLIER COMPARED TO THE 12Z
EPS/GEPS, BUT APPEARS A SMIDGE WETTER IN LINE WITH THE LATEST 00Z
GUIDANCE. EVEN WITH THAT, AMOUNTS ARE ABOUT A TENTH OF AN INCH OR
LESS.
A SECOND CHANCE OF PRECIPITATION, IN THE FORM OF SHOWERS, WILL THEN
BE POSSIBLE WED INTO LATE WED NIGHT, AS A STRONG TROUGH OVER THE MS
VALLEY TRACKS INTO THE OH VALLEY. A STRONG COLD FRONT WILL ACCOMPANY
THIS SYSTEM, MOVING THROUGH LATE WED NIGHT. SOME MORNING LIGHT RAIN
IS POSSIBLE WITH LINGERING ISENTROPIC ASCENT. A SECOND BATCH OF
SHOWERS ARE THEN POSSIBLE WED AFTN INTO THE LATE EVENING AS GUIDANCE
SHOWS PERHAPS AN AREA OF LOW PRESSURE TRACKING ALONG THE FRONT.
THERE ARE SOME SUBTLE DIFFERENCES IN THE LOCATION OF THE TROUGH,
WITH THE ECMWF/CMC WETTER AND FURTHER SOUTH THAN THE GFS. THERE
MIGHT BE A VERY SHORT WINDOW WHERE SOME ISOLATED STORMS COULD FORM
AHEAD OF THE FRONT GIVEN STRONG SHEAR, THOUGH INSTABILITY STILL
APPEARS LIMITED. TOTAL PRECIPITATION AMOUNTS ARE ABOUT A QUARTER
INCH, GIVE OR TAKE IN EITHER DIRECTION.
BEHIND THE FRONT, BRISK WSW TO WNW WINDS WILL BE IN PLACE THU
THROUGH SAT AS THE TROUGH OVER THE REGION SLOWLY LIFTS INTO THE NE
US. SUSTAINED WINDS OF 10-15 COULD GUSTS BETWEEN 25-35 MPH. HIGHS
WILL BE MUCH COOLER AND BELOW NORMAL IN THE LOW TO MID/UPPER 50S
THU/FRI, WITH SOME SLIGHT MODERATION IN THE MID 50S TO AROUND 60 BY
SAT. LOWS WILL BE NEAR NORMAL IN THE MID/UPPER 30S DUE TO PERSISTENT
STIRRING. IN REGARDS TO THE UPPER-TROUGH LATE THU THROUGH FRI, THE
ECMWF/CMC SHOW A RATHER IMPRESSIVE VORT MAX ROTATING THROUGH, WHICH
COULD PRODUCE SOME SPRINKLES/CLOUDS WITH THE STEEP LAPSE RATES. THE
GFS/GEFS ARE FURTHER NORTH WITH THIS FEATURE, SO STILL ENOUGH SPREAD
IN THE GUIDANCE TO LEAVE THE FORECAST DRY AT THE MOMENT.
AVIATION /12Z SUNDAY THROUGH THURSDAY/
AS OF 620 AM SUNDAY...
VFR CONDITIONS EXPECTED AT ALL SITES THROUGH THE PERIOD. HIGH
PRESSURE OVERHEAD WILL ALLOW FOR CALM (OR NEARLY CALM) WINDS
THROUGH 14Z-15Z, THEN A LIGHT SW SURFACE FLOW UNDER 10KT IS EXPECTED
THIS AFTERNOON.
OUTLOOK: VFR CONDITIONS ARE EXPECTED SUNDAY NIGHT THROUGH MONDAY.
A STRONG COLD FRONT MOVING THROUGH THE REGION AROUND MID-WEEK
WILL BRING A PERIOD OF SUB-VFR CONDITIONS WITH SHOWERS/GUSTY WINDS.
RAH WATCHES/WARNINGS/ADVISORIES
FROST ADVISORY FROM 4 AM TO 8 AM EST SUNDAY FOR NCZ007>011-021>028-
038>043-073>078-083-084.
SYNOPSIS...BADGETT/MWS
NEAR TERM...BADGETT
SHORT TERM...BADGETT
LONG TERM...KREN
AVIATION...BADGETT
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