897
FXUS62 KRAH 210638
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
138 AM EST THU NOV 21 2024
SYNOPSIS
SEASONALLY COOL HIGH PRESSURE WILL BUILD ACROSS THE SOUTHEAST TODAY,
WHILE A NOR'EASTER TRACKS ALONG THE COAST OF THE NORTHERN MIDDLE
ATLANTIC AND SOUTHERN NEW ENGLAND. A REINFORCING, MOSTLY DRY COLD
FRONT WILL MOVE ACROSS CENTRAL NC THIS EVENING. FOLLOWING HIGH
PRESSURE WILL BUILD ACROSS THE SOUTHEAST, WHILE MODIFYING, THROUGH
THE WEEKEND.
NEAR TERM /THROUGH TONIGHT/
AS OF 730 PM WEDNESDAY...
CURRENTLY A FEW ISOLATED LIGHT SHOWERS GENERALLY ALONG AND EAST OF
US-1 CORRIDOR, ARE CONTINUING TO MOVE EAST. BY MIDNIGHT, ALL THE
RAIN SHOULD BE OUT OF THE REGION AS THE DRY FRONT PUSHES INTO THE
REGION. AS OF THE 00Z OBSERVATIONS THE FRONT IS JUST ENTERING THE NW
PIEDMONT WITH OBSERVATIONAL GUSTS BEHIND THE FRONT RANGING FROM
25KTS TO 35KTS. A SPECIAL WEATHER STATEMENT MAY BE ISSUED FOR
STRONGER WIND GUSTS OCCURRING IN THE NEXT FEW HOURS AS THE FRONT
MOVES THROUGH. EVERYONE SHOULD USE CAUTION WHILE DRIVING AT NIGHT
FOR AND ANY TREES DOWN OR LOOSE DEBRIS. ROUND ONE OF COLD AIR WILL
RUSH IN THIS EVENING WITH TEMPERATURES DROPPING IN THE NW PIEDMONT
FROM THE LOW 60S TO MID 40S IN THE NEXT 6 HOURS AND IN THE COASTAL
PAIN REGION, TEMPERATURES ARE EXPECTED TO FALL AFTER MIDNIGHT
THROUGH THE OVERNIGHT HOURS FROM THE 50S TO THE 40S. LOW TEMPS
TONIGHT WILL BE IN THE MID 30S NW TO LOW 40S SE, WITH TOMORROW BEING
THE EVEN CHILLER NIGHT WITH EVERYWHERE EXPECTED TO BE IN THE LOW
30S.
AS OF 255 PM WEDNESDAY... LOW PRESSURE IS CURRENTLY NEAR DETROIT
WITH A COLD FRONT EXTENDING SOUTH ALONG THE APPALACHIAN MOUNTAINS.
THE BULK OF RAINFALL HAS ALREADY MOVED OUT ACROSS THE OUTER BANKS,
BUT ANOTHER AREA OF RAIN IS CURRENTLY BETWEEN RALEIGH, ROCKY MOUNT,
AND FAYETTEVILLE. THE CHANCE OF RAIN SHOULD INCREASE AGAIN BRIEFLY
ACROSS THE ENTIRE FORECAST AREA FOR A SHORT PERIOD OF TIME AS THE
COLD FRONT MOVES THROUGH THIS EVENING. THE IMMEDIATE WEATHER THREAT
AS THE COLD FRONT MOVES THROUGH WILL BE GUSTY WINDS. THESE WINDS
HAVE BEEN BUMPED UP A GOOD AMOUNT FROM THE PREVIOUS FORECAST, AND
ALL LOCATIONS ARE EXPECTED TO HAVE GUSTS ANYWHERE BETWEEN 25-40 MPH.
THESE GUSTS SHOULD REACH WESTERN COUNTIES BY 6-7PM AND EASTERN
COUNTIES BETWEEN 9-11PM, WITH THE CHANCE OF RAIN ALSO ENDING
APPROXIMATELY THE SAME TIME AS THE FRONTAL PASSAGE. THE TEMPERATURES
WILL ALSO DROP SHARPLY BEHIND THE FRONT, WITH OVERNIGHT LOWS RANGING
FROM THE MID 30S TO THE MID 40S. FROST IS NOT EXPECTED TO BE A
THREAT TONIGHT.
SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/
AS OF 255 PM WEDNESDAY...
SUNNY SKIES ARE EXPECTED FOR THE BEGINNING OF THURSDAY, WITH SOME
HIGH CLOUDS IN THE LATE MORNING AND AFTERNOON GENERALLY TO THE
NORTHWEST OF THE TRIANGLE. ANOTHER ROUND OF WIND GUSTS WITH DAYTIME
MIXING ARE EXPECTED, BUT THE GUSTS WILL NOT BE AS STRONG THURSDAY,
WITH VALUES BETWEEN 15-25 MPH. HIGHS WILL GENERALLY BE IN THE 50S,
BUT AN ISOLATED HIGH IN THE UPPER 40S OR LOWER 60S CANNOT BE RULED
OUT ACROSS THE CORNERS OF THE FORECAST AREA.
SOME HIGH CLOUDS WILL BE POSSIBLE THURSDAY NIGHT, AND THE WIND WILL
REMAIN AROUND 5 MPH OVERNIGHT. HOWEVER, WITH A DRY SECONDARY COLD
FRONT MOVING THROUGH THURSDAY EVENING, THURSDAY NIGHT'S TEMPERATURES
WILL BE COLDER THAN TONIGHT'S TEMPERATURES. HOW LOW THE TEMPERATURES
DROP WILL ULTIMATELY BE DEPENDENT ON HOW MUCH MIXING OCCURS WITH THE
WIND. THERE IS ENOUGH CONFIDENCE IN TEMPERATURES DROPPING BELOW
FREEZING THAT A FREEZE WATCH WILL BE ISSUED FOR MOST OF THE FORECAST
AREA, WITH THE EXCEPTION BEING ACROSS SOUTHEASTERN COUNTIES WHERE
THERE IS LESS CONFIDENCE IN BELOW FREEZING TEMPERATURES. THINK THE
COLDEST LOCATIONS COULD BOTTOM OUT IN THE UPPER 20S, WITH WIDESPREAD
LOWER 30S ALSO EXPECTED.
LONG TERM /FRIDAY THROUGH WEDNESDAY/
AS OF 230 PM WEDNESDAY...
* BRISK FRI MORNING WITH WIND CHILLS IN THE LOW 30S TO UPPER 20S
FROM 2 AM THROUGH 9 AM.
* PATCHY FROST POSSIBLE SAT AND SUN MORNING WITH MODERATING
TEMPERATURES THROUGH EARLY NEXT WEEK.
AN UNSEASONABLY DEEP MID/UPPER LEVEL CLOSED LOW WILL BE POSITIONED
OVER THE NORTHERN MID-ATLANTIC BY FRI MORNING. AN OCCLUDED SURFACE
LOW WILL WOBBLE OVER THE NORTHERN MID-ATLANTIC THROUGH FRI AND
PROVIDE A STRONG PRESSURE GRADIENT OVER THE AREA AS THE SURFACE LOW
DEEPENS TO AROUND 990MB. THIS SHOULD PROMPT A BRISK SURFACE WIND
THROUGH MUCH OF THE DAY ON FRI. TEMPERATURES WILL STRUGGLE TO GET
OUT OF THE UPPER 40S ACROSS THE NORTH AND LOW 50S ACROSS THE SOUTH
AS WINDS INCREASE TO AROUND 15 MPH WITH GUSTS 20 TO 30 MPH, ALTHOUGH
INFREQUENT GUSTS UP TO 35 MPH CAN'T BE RULED OUT. SIMILAR WIND GUSTS
ARE EXPECTED SAT AS WELL AS THE SURFACE LOW SLOWLY SHIFTS INTO THE
NORTHEAST THROUGH THE AFTERNOON. THERE IS SOME UNCERTAINTY ON IF
THESE GUSTS WILL CONTINUE OVERNIGHT. POINT SOUNDINGS FROM THE 12Z
GFS SHOW A CONTINUED MIXED LAYER OVERNIGHT FRI NIGHT INTO SAT WHEN
SOME GUSTINESS MY CONTINUE, BUT THE 12Z NAM ESTABLISHES A WEAK
STABLE LAYER AT THE SURFACE AND PREVENTS THE STRONGER GUSTS FROM
REACHING THE SURFACE.
WITH THE GRADUALLY MODIFYING CANADIAN AIRMASS IN PLACE BY FRI
MORNING, OVERNIGHT LOWS WILL SOLIDLY BE IN THE 30S EACH NIGHT, BUT
CONFIDENCE IS LOW IF THEY WILL REACH FROST/FREEZE CRITERIA. STIRRING
OVERNIGHT FRI NIGHT INTO SAT SHOULD PREVENT RADIATIONAL COOLING WITH
POCKETS FALLING BELOW 36 DEGREES IN THE OUTLYING AREAS OF THE
PIEDMONT. SAT NIGHT INTO SUN MORNING HAS A BETTER CHANCE TO FALL
BELOW 36 DEGREES AS THE PRESSURE GRADIENT BEGINS TO RELAX AND A
SHALLOW INVERSION IS ABLE TO DEVELOP AND DEEPEN. COLDEST
TEMPERATURES WILL LIKELY BE ACROSS THE SOUTHWEST QUADRANT OF THE
FORECAST AREA WHERE CALM CONDITIONS ARE EXPECTED WITH CLEAR SKIES.
TEMPERATURES WILL SLOWLY MODERATE THROUGH NEXT WEEK AS THE SURFACE
HIGH SHIFTS OUT OVER THE WESTERN ATLANTIC BY MON AND RETURNS A
SOUTHWEST LOW-LEVEL FLOW TO THE REGION. A LOW AMPLITUDE SYSTEM AND
WEAK SURFACE REFLECTION IS FORECAST TO PASS THROUGH THE GREAT LAKES
AND INTO ONTARIO LATE MON INTO TUES, BUT ONLY AN INCREASE IN CLOUDS
AND A DRY COLD FRONTAL PASSAGE IS EXPECTED FOR OUR AREA.
AVIATION /06Z THURSDAY THROUGH MONDAY/
AS OF 135 AM THURSDAY...
EARLIER STRONG AND GUSTY NWLY SURFACE WINDS, BEHIND A COLD FRONT NOW
MOVING OFF THE NC COAST, WILL CONTINUE TO LESSEN THIS MORNING, WHILE
NWLY WINDS JUST ABOVE THE SURFACE WILL INITIALLY REMAIN STRONG AND
FAVOR MARGINAL LOW LEVEL WIND SHEAR THROUGH 09-10Z. INDEED, BOTH
RADAR-DERIVED WIND DATA AND TELEVISION TALL TOWER DATA HAVE SAMPLED
35-45 KT WINDS BETWEEN 1200-2000 FT IN THE PAST COUPLE OF HOURS.
WHILE WINDS IN THAT LAYER WILL ALSO WEAKEN LATER THIS MORNING, THEY
WILL REMAIN IN THE 20S KTS AND FAVOR THE REDEVELOPMENT OF GUSTY, WLY
SURFACE WINDS WITH DAYTIME HEATING/MIXING. THESE SURFACE WINDS MAY
BECOME LOCALLY ENHANCED BENEATH 6-9 THOUSAND FT CEILINGS AND VIRGA
THAT WILL ACCOMPANY A VIGOROUS TROUGH ALOFT AND REINFORCING SURFACE
COLD FRONT LATE THIS AFTERNOON THROUGH THIS EVENING. A FOLLOWING,
POST-FRONTAL SURGE OF NWLY WINDS JUST ABOVE THE SURFACE MAY RESULT
IN ANOTHER EPISODE OF MARGINAL LOW LEVEL WIND SHEAR THIS EVENING,
SINCE SURFACE WINDS WILL GENERALLY DIMINISH AROUND SUNSET.
OUTLOOK: LOW VFR STRATOCUMULUS CEILINGS BETWEEN 3-4 THOUSAND FT WILL
BE POSSIBLE AT INT/GSO FRI MORNING, AS WILL MORE VIRGA OR EVEN A FEW
FLURRIES AT THE SURFACE, AS ANOTHER STRONG DISTURBANCE ALOFT PIVOTS
ACROSS THE REGION. NWLY SURFACE WINDS WILL BECOME GUSTY INTO THE 20S
KTS AGAIN FRI, WITH MOSTLY TEENS KTS EXPECTED ON SAT.
RAH WATCHES/WARNINGS/ADVISORIES
FREEZE WATCH FROM LATE THURSDAY NIGHT THROUGH FRIDAY MORNING FOR
NCZ007>011-021>028-038>043-073>077-083>086.
SYNOPSIS...MWS
NEAR TERM...CA/GREEN
SHORT TERM...GREEN
LONG TERM...SWIGGETT
AVIATION...MWS
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