152
FXUS62 KRAH 202010
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
310 PM EST WED NOV 20 2024
SYNOPSIS
A COLD FRONT MOVING ACROSS THE AREA TONIGHT WILL BRING GUSTY WINDS
AND MUCH COLDER AIR FOR THE END OF THE WEEK. HIGH PRESSURE WILL
ALLOW TEMPERATURES TO BEGIN MODERATING FOR THE WEEKEND.
NEAR TERM /THROUGH TONIGHT/
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 /18Z WEDNESDAY THROUGH MONDAY/
AS OF 1245 PM WEDNESDAY...
TAF PERIOD: AN AREA OF RAIN HAS MOVED THROUGH MUCH OF THE REGION,
WITH IFR/LIFR CONDITIONS AT ALL SITES. AN ANOTHER AREA OF RAIN COULD
FILL BACK INTO THE AREA DURING THE LATE AFTERNOON AND EVENING HOURS.
A COLD FRONT WILL MOVE THROUGH DURING THE EVENING, BRINGING DRIER
AIR (MIXING OUT THE LOW CEILINGS) AS WELL AS GUSTY WINDS. HAVE GONE
WITH 25-30 KT WINDS IN THE TAFS, BUT SOME MODEL GUIDANCE IS
INDICATING THAT GUSTS ALONG THE FRONT COULD BE IN THE 30-40 KT
RANGE, AND THIS WILL REQUIRE FURTHER INVESTIGATION. AFTER A 3-6 HR
WINDOW, IT APPEARS THAT ALL SITES SHOULD HAVE GUSTS COME TO AN END
DURING THE OVERNIGHT PERIOD WITH CLEARING SKIES. AFTER SUNRISE,
DAYTIME MIXING SHOULD ALLOW FOR ANOTHER ROUND OF GUSTS, ALTHOUGH
THURSDAY'S GUSTS SHOULD NOT BE NEARLY AS STRONG AS THE OVERNIGHT
WINDS, CLOSER TO 20 KT WIND. SOME HIGHER CLOUDS WILL LIKELY MOVE
INTO THE TRIAD LATE THURSDAY MORNING, ALTHOUGH THESE WILL NOT BRING
ANY FLIGHT RESTRICTIONS.
OUTLOOK: NO PRECIPITATION IS IN THE FORECAST DURING THE OUTLOOK
PERIOD WITH VFR CONDITIONS. FRIDAY AND SATURDAY WILL HAVE GUSTS TO
25 KT.
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...GREEN
NEAR TERM...GREEN
SHORT TERM...GREEN
LONG TERM...SWIGGETT
AVIATION...GREEN
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