171
FXUS62 KRAH 200545
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
1245 AM EST FRI DEC 20 2024
SYNOPSIS
AN ARCTIC COLD FRONT AND STRONG UPPER LEVEL DISTURBANCE WILL
APPROACH FROM THE WEST EARLY THIS MORNING AND CROSS THE AREA TODAY
THROUGH TONIGHT. THIS WILL BRING MUCH COLDER AIR INTO THE REGION FOR
THE WEEKEND.
NEAR TERM /THROUGH TONIGHT/
AS OF 815 PM THURSDAY...
WEAK SOUTHERLY OVERRUNNING AND ISENTROPIC LIFT ATOP A WEDGE OF COOL
HIGH PRESSURE EXTENDING SOUTH DOWN THE ATLANTIC SEABOARD IS
SUPPORTING WIDESPREAD STRATUS WITH CLOUD BASES RUNNING BETWEEN 2-
5KFT ACROSS THE AREA. UPPER LEVEL FORCING OVERSPREADING THE AREA
DURING THE LATTER HALF OF THE NIGHT, VIA INCREASING UPPER JET
DIVERGENCE AND 80-140M H5 HEIGHT FALLS DUE TO THE ARRIVAL OF A
STRENGTHENING UPPER PV ANOMALY INTO THE SOUTHERN AND CENTRAL
APPALACHIANS WILL AIDE IN THE DEVELOPMENT OF LIGHT PATCHY RAIN AND
DRIZZLE. BEST CHANCES SEEM TO BE ALONG AND EAST OF US-1.
OVERNIGHT LOWS RANGING FROM MID 30S ALONG THE VA BORDER TO AROUND
40 ACROSS THE SOUTHERN COUNTIES.
SHORT TERM /FRIDAY AND FRIDAY NIGHT/
AS OF 225 PM THURSDAY...
A DEEPENING UPPER LEVEL TROUGH WILL SWING ACROSS OUR REGION FRIDAY
BEFORE CLEARING THE REGION EARLY SATURDAY MORNING. AT THE SURFACE, A
LOW PRESSURE OFFSHORE WILL SKIRT UP THE MID-ATLANTIC COAST THROUGH
THE DAY BRINGING SCATTERED SHOWERS AND A FEW ISOLATED STORMS THE
COASTAL PLAIN AND SANDHILLS REGION, EARLY FRIDAY. TO THE WEST,
ANOTHER SURFACE LOW CENTERED OVER THE OH VALLEY IS EXPECTED TO TREK
SOUTHEAST TOWARDS THE APPALACHIAN MOUNTAINS ALONG WITH A A TRAILING
COLD FRONT. THE LOW WILL MOVE TO THE NORTHEAST, AND THE COLD FRONT
WILL MOVE ACROSS THE REGION FRIDAY BRINGING SCATTERED SHOWERS AND
ISOLATED STORMS. ALL PRECIP SHOULD CLEAR OUT OF THE REGION BY THE
EVENING HOURS AS THE COLD AIR RUSHES IN BEHIND THE PRECIP. A FEW
GUSTS ARE POSSIBLE AS THE COLD FRONT MOVES OVER THE REGION AS WELL.
FRIDAY HIGH TEMPERATURES WILL BE BELOW AVERAGE RANGING FROM UPPER
40S TO LOW 50S. LOWS WILL GENERAL BE IN THE LOW TO MID 30S WITH A
FEW COOLER SPOTS IN THE UPPER 20S.
LONG TERM /SATURDAY THROUGH THURSDAY/
AS OF 255 PM THURSDAY...
THIS WEEKEND, A COOL 1040MB HIGH PRESSURE WILL BUILD TO OUR NORTH
BRINGING COLD, DRY AIR TO THE REGION. SATURDAY WILL HAVE HIGH
TEMPERATURES IN THE MID TO UPPER 50S, WITH LOW TEMPERATURES IN THE
LOW TO MID 20S. SUNDAY WILL BE THE COLDEST DAY OF THE PERIOD AS THE
SURFACE HIGH IS OVERHEAD, WITH HIGHS IN THE UPPER 30S TO LOW 40S.
SUNDAY NIGHT WILL BE THE COLDEST NIGHT OF THE PERIOD AS CLEAR SKIES
WILL HELP PROMOTE GOOD RADIATIONAL COOLING AND LOWER LEVEL
THICKNESSES ARE AROUND 1265-1275 DAM, ALLOWING LOWS TO GET DOWN IN
THE MID TEENS TO LOW 20S.
TEMPERATURES WILL START TO MODERATE THROUGH THE BEGINNING OF THE
WORK WEEK AS THE MID/UPPER LEVEL TROUGH MOVES OFFSHORE AND WE RETURN
TO QUASI-ZONAL MID/UPPER LEVEL FLOW. THUS, MONDAY'S HIGH
TEMPERATURES SHOULD BE IN THE LOW TO MID 40S, WITH LOWS IN THE 20S.
TEMPERATURES SHOULD CONTINUE TO WARM EACH DAY, WITH HIGHS INCREASING
FROM UPPER 40S AND MID 50S ON TUESDAY TO 50S AND LOW 60S BY
THURSDAY. LOWS SHOULD ALSO INCREASE FROM AT OR ABOVE FREEZING ON
TUESDAY NIGHT TO LOW TO MID 40S BY THURSDAY NIGHT.
THE NEXT CHANCE OF RAIN COMES CHRISTMAS DAY AS A SHORT WAVE TROUGH
APPROACHES THE REGION. MODELS DIFFER ON HOW THEY HANDLE THIS
DISTURBANCE, BUT THERE IS GENERAL AGREEMENT IN UNSETTLED WEATHER
IMPACTING THE REGION ON WEDNESDAY INTO THURSDAY THEREFORE SLIGHT
CHANCE AND LOW END CHANCE POPS STARTING CHRISTMAS AFTERNOON THROUGH
THURSDAY AFTERNOON WERE INCLUDED. TEMPERATURES WILL GENERALLY BE IN
THE UPPER 40S TO 50S SO ANY PRECIPITATION THAT FALLS WILL BE ALL
LIQUID.
AVIATION /06Z FRIDAY THROUGH TUESDAY/
AS OF 1245 AM FRIDAY...
CONFIDENCE IS HIGH THAT MVFR CONDITIONS WILL DOMINATE CENTRAL NC
TERMINALS THROUGH MID MORNING, A RESULT OF HIGH MOISTURE AND VERY
LIGHT WINDS THROUGH THE LOWEST 3-4 KFT. PATCHY DRIZZLE IS ALSO
POSSIBLE 08Z-13Z MAINLY AT EASTERN TERMINALS, BUT VSBYS SHOULD
REMAIN VFR REGARDLESS. STARTING MID MORNING, AS A SERIES OF UPPER
LEVEL DISTURBANCES CROSSES THE AREA AHEAD OF AN ARCTIC COLD FRONT,
CIGS WILL BE MOSTLY MVFR, BUT CIGS MAY BRIEFLY POP UP TO VFR BETWEEN
14Z AND 18Z. BROKEN BANDS OF LIGHT SHOWERS ARE EXPECTED TO CROSS THE
AREA, MAINLY LATE MORNING THROUGH EARLY AFTERNOON, THEN AGAIN FROM
LATE AFTERNOON THROUGH THE EVENING, WITH MOSTLY MVFR CIGS THROUGH
THE REST OF THE TAF VALID PERIOD. SURFACE WINDS WILL BE GENERALLY
LIGHT AND VARIABLE UNDER 6 KT, BUT LATE IN THE PERIOD (AFTER 01Z)
WINDS AT INT/GSO WILL INCREASE TO 10-15 KT GUSTING TO 15-20 KTS FROM
THE NW AS THE SURFACE COLD FRONT MOVES IN.
LOOKING BEYOND 06Z SAT, MVFR CIGS MAY LINGER FOR A FEW MORE HOURS IN
THE EAST, BUT AFTER 09Z ALL TERMINALS SHOULD HAVE BECOME VFR WITH
CLEARING SKIES AND A BREEZE FROM THE NW. VFR CONDITIONS WILL
PREVAIL THROUGH TUE UNDER COLD HIGH PRESSURE. -GIH
RAH WATCHES/WARNINGS/ADVISORIES
NONE.
SYNOPSIS...HARTFIELD
NEAR TERM...CBL
SHORT TERM...CA
LONG TERM...HELOCK
AVIATION...HARTFIELD
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