490
FXUS62 KRAH 190808
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
305 AM EST SUN JAN 19 2025
SYNOPSIS
AN AREA OF LOW PRESSURE AND COMPLEX FRONTAL ZONE WILL LIFT NORTHEAST
THROUGH THE AREA THROUGH THE AFTERNOON. ARCTIC HIGH PRESSURE WILL
BEHIND IN THIS EVENING AND TONIGHT AND BRING BITTER COLD TEMPERATURES
INTO THE REGION THROUGH THE MIDDLE OF NEXT WEEK.
NEAR TERM /TODAY AND TONIGHT/
AS OF 300 AM SUNDAY...
..PERIODS OF RAIN SHOWERS THROUGH THE AFTERNOON
..ARCTIC AIR ARRIVES TONIGHT
EMBEDDED AND ROUNDING THE BASE OF THE DEEP LONG WAVE TROUGH THAT
ENCOMPASSES THE ENTIRE CONUS, A SHORTWAVE TROUGH IS FORECAST TO
TRAVERSE THE SOUTHERN/CENTRAL APPALACHIANS TODAY AND THEN ACCELERATE
ACROSS THE NORTHERN MID ATLANTIC THIS EVENING AND TONIGHT. AS THE
SUBTROPICAL AND POLAR JET STREAMS CONVERGE AND STRENGTHEN OVER THE
REGION, A DEVELOPING WAVE OF LOW PRESSURE OVER THE CAROLINAS WILL
RIDE NE ALONG A COMPLEX FRONTAL ZONE THAT WILL MOVE NE ACROSS THE
EASTERN HALF OF NC THROUGH THE MORNING AND EARLY AFTERNOON, JUST
AHEAD OF THE SLOW MOVING ARCTIC COLD FRONT THAT WILL PASS THROUGH
THE AREA DURING THE LATE AFTERNOON AND EVENING.
A MIXTURE OF STRATUS AND FOG HAS DEVELOPED ACROSS CENTRAL NC, WITH
SOME AREAS OF DENSE FOG BEING OBSERVED. THESE LOWER VISIBILITY
RESTRICTIONS(0.25-0.5 MILE) OVER THE SANDHILLS AND COASTAL PLAIN
SHOULD START IMPROVE AS WARM FRONTAL RAIN SHOWERS, MOST EXTENSIVE
ALONG AND EAST OF US 1, SPREAD NE THROUGH THE AREA DURING THE
MORNING AND EARLY AFTERNOON HOURS. THIS AREA OF SHALLOW CONVECTION
SHOULD MOVE NORTH INTO VA ~ 18Z, FOLLOWED BY ISOLATED TO WIDELY
SCATTERED SHOWERS THROUGH 00Z AS THE ARCTIC COLD FRONT MOVES EAST
THROUGH THE AREA. THE HIGHEST RAINFALL AMOUNTS ARE EXPECTED TO RANGE
FROM UP TO A QUARTER TO HALF INCH INCH OR MORE IS OVER THE EASTERN
SANDHILLS AND SOUTHERN COASTAL PLAIN. FURTHER NORTH AND WEST, A
TENTH OF AN INCH OR LESS IS EXPECTED.
THE SURFACE LOW AND COMPLEX FRONTAL ZONE WILL RESULT IN A SHARP NW
TO SE TEMP GRADIENT ACROSS THE AREA. HIGHS IN THE MID/UPPER 50S AND
EVEN SOME LOWER 60S IN THE WARM SECTOR, TO LOWER/MID 40S ON THE COOL
SIDE OF THE LEAD FRONTAL ZONE. WINDS WILL INCREASE AND GUSTS WILL
DEVELOP BEHIND THE EXITING LEAD SFC WAVE. EXPECT GUSTS OF 20 TO 30
MPH AT TIMES , STRONGEST ACROSS THE SOUTH.
STRONG COLD AIR ADVECTION TONIGHT SHOULD ALLOW SOME GUSTINESS OF 15
TO 20 MPH TO LINGER WELL INTO THE OVERNIGHT HOURS. LOWS MONDAY
MORNING IN UPPER TEENS NW TO MID/UPPER 20S SE, WITH SOME WIND CHILLS
IN THE HIGH SINGLE DIGITS TO TEENS(JUST ABOVE CRITERIA FOR COLD
WEATHER ADVISORY).
SHORT TERM /MONDAY AND MONDAY NIGHT/
AS OF 300 AM SUNDAY...
..FIRST DAY OF BITTERLY COLD TEMPERATURES
UNDER THE INFLUENCE OF AN EXPANSIVE ARCTIC HIGH PRESSURE SYSTEM THAT
COVERS MUCH OF THE CONUS, HIGHS WILL AVERAGE 20 DEGREES BELOW NORMAL
WITH MUCH OF THE PIEDMONT, AND NORTHERN COASTAL PLAIN COUNTIES
EXPECTED TO STAY JUST AT OR BELOW FREEZING. HIGHS RANGING FROM
MID/UPPER 20S NW TO MID 30S SE WITH INTERMITTENT GUSTINESS OF 15 TO
20 MPH RESULTING IN EXPECTED WIND CHILLS IN THE UPPER TEENS TO 20S.
PRESSURE GRADIENT RELAXES ENOUGH THAT WINDS BECOME LIGHT MONDAY
NIGHT. SKIES WILL START OUT MOSTLY CLEAR, BUT MODELS DO SHOW AN
INCREASE IN JET CIRRUS CLOUDS AFTER MIDNIGHT, ESPECIALLY OVER THE
SOUTHERN HALF OF THE FORECAST AREA. LOWS IN THE LOWER TO MIDDLE
TEENS, WITH SOME UPPER SINGLE DIGITS POSSIBLE IN THE COLDER OUTLYING
AREAS.
LONG TERM /TUESDAY THROUGH SATURDAY/
AS OF 455 PM SATURDAY...
* FORECAST CONFIDENCE REMAINS HIGH FOR A CONTINUATION OF WELL BELOW
AVERAGE TEMPERATURES THIS PERIOD, MAXIMIZED WITH DEPARTURES FROM
NORMAL OF 15-25 F MID-WEEK.
* FORECAST CONFIDENCE IS LOW REGARDING THE NORTHERN EXTENT OF
(WINTRY) PRECIPITATION ACROSS CNTL-ERN NC, AS GENERALLY
FLAT/SUPPRESSED/WEAK LOW PRESSURE TRACKS FROM THE GULF OF MEXICO TO
WELL OFFSHORE THE SOUTH AND SOUTHERN MIDDLE ATLANTIC COASTS TUE-
EARLY WED.
A HIGHLY AMPLIFIED MID/UPR-LEVEL PATTERN WILL BE CHARACTERIZED BY A
RIDGE OVER THE ERN PACIFIC AND MEAN TROUGHS THAT WILL PIVOT ACROSS
THE CNTL-ERN US. THE FIRST OF THOSE TROUGHS, AND MOST INFLUENTIAL
FOR THE THREAT OF WINTRY PRECIPITATION (SNOW) INTO CNTL NC, WILL BE
A POSITIVELY-TILTED AND AT LEAST PARTIALLY PHASED TROUGH THAT WILL
EXTEND FROM THE UPR GREAT LAKES TO THE SOUTHWEST AT 12Z TUE AND
PIVOT ACROSS AND OFFSHORE THE SOUTH AND SRN MIDDLE ATLANTIC THROUGH
WED. IT SHOULD BE NOTED THAT THE MOST-BASAL OF THOSE SHORTWAVE
PERTURBATIONS JUST ENTERED THE NORTH AMERICAN RAOB NETWORK NEAR
ANNETTE ISLAND AND YAKUTAT, ALASKA THIS MORNING. FURTHER SAMPLING OF
THIS FEATURE ACROSS WRN BRITISH COLUMBIA AND THE PACIFIC NORTHWEST
THROUGH 12Z SUNDAY MAY BETTER RESOLVE ITS PRESENCE AND DOWNSTREAM
SYNOPTIC INFLUENCE AND ULTIMATELY DECREASE ABOVE AVERAGE MODEL
SPREAD IN SOLUTIONS OF ITS IMPACT TO SRN US WINTRY WEATHER TUE-TUE
NIGHT. THE OTHER SHORTWAVE PERTURBATIONS FORECAST TO COMPRISE THE
POSITIVE-TILT TROUGH SHOULD ALSO BECOME BETTER-RESOLVED FOR MODEL
INITIAL CONDITIONS, AS THEY DIG SHARPLY SSEWD FROM THE NORTHWEST
TERRITORIES AND YUKON TO THE CNTL CANADIAN PRAIRIES. LOW AMPLITUDE
SHORTWAVE RIDGING WILL THEN PROGRESS ACROSS AND OFFSHORE THE MIDDLE
AND SOUTH ATLANTIC LATER WED-WED NIGHT, DOWNSTREAM OF A TROUGH THAT
WILL RELOAD AND PIVOT FROM THE GREAT PLAINS AND MS VALLEY TO THE
EAST COAST THROUGH SAT.
AT THE SURFACE, ARCTIC HIGH PRESSURE WILL INITIALLY SPRAWL FROM THE
CNTL GREAT BASIN TO THE MIDDLE ATLANTIC, THEN GRADUALLY WEAKEN AS IT
MIGRATES EWD AND BECOMES CENTERED OVER THE MIDDLE ATLANTIC THROUGH
THE END OF THE WEEK. A FRONTAL ZONE WILL BE SUPPRESSED WELL-
SOUTHWARD ACROSS THE SUB-TROPICS, FROM THE GULF OF MEXICO TO THE
SWRN N. ATLANTIC, ALONG THE SRN/EQUATORWARD DRAPE OF THE EXPANSIVE
ARCTIC HIGH AND AIRMASS THROUGH MID-WEEK; AND MODEL AGREEMENT IS
RELATIVELY HIGH REGARDING ONLY WEAK/FLAT FRONTAL WAVE DEVELOPMENT
ALONG THAT FRONTAL ZONE FROM THE GULF OF MEXICO TO OFFSHORE THE
SOUTH ATLANTIC COAST TUE-TUE NIGHT. WHILE SOME MODELS DEPICT MORE
SUBSTANTIAL DEEPENING OF THE LOW AS IT TRACKS BETWEEN CAPE HATTERAS
AND BERMUDA, ANY SUCH DEVELOPMENT AND DEEPENING WOULD BE TOO LATE
AND INCONSEQUENTIAL FOR SIGNIFICANT IMPACTS TO CNTL NC. THE
AFOREMENTIONED RE-LOADING OF THE TROUGH ALOFT INITIALLY INTO THE
CNTL US MAY ALLOW THE SURFACE FRONTAL ZONE AND SUBSEQUENT
CYCLOGENESIS TO BUCKLE POLEWARD AND NEARER THE MIDDLE ATLANTIC AND
SRN NEW ENGLAND COASTS LATER IN THE WEEK, WITH POSSIBLE ADDITIONAL,
LOW CONFIDENCE PRECIPITATION IMPACTS INTO CNTL NC.
THE PREVIOUSLY VERY WET SOLUTIONS ON THE EXTREME NWRN EDGE OF THE
GUIDANCE ENVELOPE, LED BY THE GEM AND GEPS, HAVE TRENDED SOUTHWARD
AND DRIER AND NOW FORM A STRONG CONSENSUS CLUSTER OF GUIDANCE WITH
EPS SOLUTIONS OF THE PAST COUPLE OF DAYS. WHILE THIS CLUSTER
APPEARS TO BE A FAVORED AND REASONABLE SOLUTION FOR MEASURABLE SNOW
AND LOW TO MODERATE IMPACTS ACROSS E-CNTL NC, THE MUCH DRIER AND SWD-
SUPPRESSED GFS AND GEFS SOLUTIONS HAVE SUPPORT OF THE EC-AIFS AND
PRODUCE VERY LITTLE SNOW INTO CNTL AND EVEN SERN NC. FORECAST
CONFIDENCE CONSEQUENTLY REMAINS BELOW AVERAGE AT THIS TIME.
VERY COLD CONDITIONS, AND DRY ONES, WED-WED NIGHT WILL THEN
GRADUALLY MODERATE INTO THE UPCOMING WEEKEND, AS THE ARCTIC HIGH AND
AIRMASS GRADUALLY WEAKEN AND LOSE INFLUENCE. AS THE ARCTIC AIR DOES
SO, HOWEVER, SUFFICIENTLY COLD AIR MAY REMAIN IN PLACE TO PRESENT
ADDITIONAL P-TYPE CONCERNS AS MOISTURE IS DRAWN NWWD WITH THE
AFOREMENTIONED OFFSHORE FRONTAL ZONE AND POSSIBLE RENEWED
CYCLOGENESIS NEAR THE MIDDLE ATLANTIC COAST. FOR NOW, AND GIVEN HIGH
UNCERTAINTY, JUST A SLIGHT CHANCE OF MIXED PRECIPITATION WILL BE
ADVERTISED MAINLY OVER THE ERN HALF OF CNTL NC THU INTO FRI.
AVIATION /06Z SUNDAY THROUGH THURSDAY/
AS OF 100 AM SUNDAY...
A DEVELOPING WAVE OF LOW PRESSURE OVER THE CAROLINAS WILL RIDE NE
ALONG A COMPLEX FRONTAL ZONE THAT WILL MOVE THROUGH THE AREA THROUGH
THE AFTERNOON. A MIXTURE OF STRATUS AND FOG HAS DEVELOPED AHEAD OF
THE SYSTEM, WITH FLIGHT RESTRICTIONS EXPECTED TO LOWER TO LIFR AT
ALL TAF SITES OVERNIGHT. RAIN WILL BEGIN TO OVERSPREAD CENTRAL AND
EASTERN NC AS A WARM FRONT LIFTS NORTH INTO THE AREA. THIS AREA OF
RAIN SHOULD MOVE NORTH INTO VA ~ 18Z, FOLLOWED BY ISOLATED TO WIDELY
SCATTERED SHOWERS THROUGH 00Z AS THE ARCTIC COLD FRONT MOVES EAST
THROUGH THE AREA. THE RESULTANT STRONG COLD DRY AIR ADVECTION WILL
SCATTER OUT THE SUB-VFR RESTRICTIONS FROM SW TO NE BETWEEN 18Z-02Z.
ADDITIONALLY, WESTERLY AND NWLY GUSTINESS OF 20-25KTS WILL DEVELOP.
THE GUSTINESS COULD LINGER INTO THE OVERNIGHT HOURS.
OUTLOOK: VFR CONDITIONS ARE EXPECTED MONDAY AND TUESDAY. FORECAST
UNCERTAINTY IS HIGH, HOWEVER A POTENTIAL WINTER STORM SYSTEM COULD
BRING SUB-VFR RESTRICTIONS IN THE FORM OF SNOW TUESDAY AFTERNOON
THROUGH EARLY WEDNESDAY.
CLIMATE
RECORD LOW MAXIMUM TEMPERATURES:
JANUARY 20:
KGSO: 29/1983
KRDU: 28/1970
JANUARY 21:
KFAY: 31/1983
JANUARY 22:
KGSO: 29/2014
KRDU: 27/1970
RAH WATCHES/WARNINGS/ADVISORIES
NONE.
SYNOPSIS...SWIGGETT/CBL
NEAR TERM...CBL
SHORT TERM...CBL
LONG TERM...MWS
AVIATION...CBL
CLIMATE...RAH
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page