509
FXUS62 KRAH 201858
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
158 PM EST FRI DEC 20 2024
SYNOPSIS
AN ARCTIC COLD FRONT AND STRONG UPPER LEVEL DISTURBANCE WILL
APPROACH FROM THE WEST 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 156 PM FRIDAY...
NOT MUCH CHANGE TO THE FORECAST THIS AFTERNOON THROUGH TONIGHT. CAMS
ARE STILL IN GOOD AGREEMENT PINPOINTING THE WESTERN/SOUTHERN
PIEDMONT AND SANDHILLS VICINITY FOR SCATTERED SHOWERS EARLY THIS
EVENING. STILL COULD BE A CRACK OF THUNDER OR TWO GIVEN EXPECTED
STEEP LAPSE RATES, BUT OVERALL LIGHTNING ACTIVITY SHOULDN'T BE TOO
MUCH OF A CONCERN. STILL EXPECTING JUST A FEW HUNDREDS TO PERHAPS A
FEW TENTHS OF AN INCH WITH ANY PASSING SHOWER. OTHERWISE, THE COLD
FRONT WILL PASS THROUGH TONIGHT, WITH A BRIEF PERIOD OF GUSTINESS
(15 TO 25 MPH) WHICH SHOULD SUBSIDE SOME (BUT REMAIN STIRRED)
OVERNIGHT. LOWS IN THE LOWER 30S EXPECTED.
PREVIOUS DISCUSSION FROM THIS MORNING...
LOW-LEVEL OVERCAST CONTINUES THIS MORNING AHEAD OF A STRONG COLD
FRONT THAT'S JUST ENTERING CENTRAL TN/KY. ALOFT, A STRONG VORTMAX
WAS EVIDENT ON SATELLITE SPIRALING SOUTHEASTWARD OVER THE IN/OH/KY
VICINITY. LATEST GUIDANCE SUGGESTS THIS MID-LEVEL VORT MAXIMA WILL
SLIDE ACROSS THE SOUTHERN APPALACHIANS LATE THIS AFTERNOON, AND THEN
OVER THE SOUTHERN PORTIONS OF OUR AREA EARLY THIS EVENING. GIVEN
THE RESIDUAL LOW-LEVEL MOISTURE IN PLACE AHEAD OF THE FRONT
(CONFIRMED BY THE 12Z KGSO SOUNDING), THERE STILL APPEARS A DECENT
CHANCE FOR ISOLATED TO SCATTERED SHOWERS TO DEVELOP LATE THIS
AFTERNOON AND EARLY THIS EVENING. LATEST CAMS ARE IN DECENT
AGREEMENT SPINNING MOST OF THIS ACTIVITY UP OVER OUR WESTERN AND FAR
SOUTHWESTERN PIEDMONT/SANDHILLS DURING THIS PERIOD (NON-ZERO CHANCE
SOMETHING REACHES THE TRIANGLE). OVERALL THOUGH, ANY QPF WITH THESE
SHOWERS SHOULD BE LIMITED TO GENERALLY A FEW HUNDREDS TO MAKE A FEW
TENTHS OF AN INCH AND NOT BE IMPACTFUL. IT IS WORTH NOTING, HOWEVER,
THAT FORECAST SOUNDINGS DO INDICATE THE POTENTIAL FOR STEEP LAPSE
RATES DURING THIS PERIOD (PARTICULARLY IN THE SOUTHERN
PIEDMONT/SANDHILLS). AS SUCH, WOULD NOT BE SURPRISED IF WE HAVE A
FEW STRIKES OF LIGHTNING WITH ANY "DEEPER" SHOWER.
HIGHS TODAY WILL MAX IN THE UPPER 40S TO LOWER 50S. OVERNIGHT LOWS
WILL DIP INTO THE LOWER 30S. EXPECT A PERIOD OF 15 TO 25 MPH GUSTS
BEHIND THE FRONT THIS EVENING, SUBSIDING SOME OVERNIGHT (BUT
REMAINING MIXED).
SHORT TERM /SATURDAY AND SATURDAY NIGHT/
AS OF 156 PM FRIDAY...
POST-FRONTAL CAA WILL PROMOTE CHILLY HIGHS IN THE LOWER TO MID 40S
SATURDAY AFTERNOON. SUNNY SKIES AND DRY CONDITIONS WILL PERSIST
THROUGH THE PERIOD. LATE MORNING TO MID-AFTERNOON NWLY GUSTS OF UP
TO 15 TO 20 MPH WILL BE POSSIBLE, SUBSIDING SOME AFTER DARK.
HOWEVER, FORECAST SOUNDINGS INDICATE SOME STIRRING OF THE BOUNDARY
LAYER LOOKS LIKELY SATURDAY NIGHT. SO WHILE THE COLD AIR MASS WILL
PROMOTE CHILLY OVERNIGHT LOWS IN THE LOWER 20S, THE REALLY COLD
MORNING (WITH PRISTINE RADIATIVE COOLING POTENTIAL) WILL HOLD OFF
TILL SUNDAY NIGHT.
LONG TERM /SUNDAY THROUGH FRIDAY/
AS OF 130 PM FRIDAY...
SUNDAY IS EXPECTED TO BE THE COLDEST DAY OF THE 7 DAY PERIOD. A
STRONG 1035+ MB ARCTIC HIGH OVER THE GREAT LAKES REGION EXTENDS DOWN
ACROSS THE MID-ATLANTIC REGION SUNDAY INTO MONDAY BEFORE SHIFTING
OFF THE NORTHEAST COAST LATE MONDAY NIGHT. HIGH TEMPS SUNDAY ARE
EXPECTED TO BE IN THE UPPER 30S TO LOW 40S WITH WINDS CHILLS IN THE
30S ACROSS THE REGION. AS WINDS CALM LATE SUNDAY EVENING, CLEAR
SKIES WILL HELP AID EXCELLENT RADIATIONAL COOLING WITH LOWS DROPPING
DOWN INTO THE TEENS TO LOW 20S FOR MUCH OF THE OVERNIGHT HOURS.
MONDAY WILL BE A TAD WARMER AS THE HIGH SHIFTS OFFSHORE WITH HIGH
TEMPERATURES IN THE LOW TO MID 40S AND LOWS IN THE MID/UPPER 20S
MONDAY NIGHT.
BY TUESDAY MORNING A LOW PRESSURE SYSTEM MOVING ACROSS THE GREAT
LAKES REGION WITH A COLD FRONT TRAILING BEHIND OVER THE OH VALLEY
WILL MAKE ITS WAY TO THE MID-ATLANTIC REGION TUESDAY OR WEDNESDAY.
MOST OF WEDNESDAY IS EXPECTED TO BE CLOUDY, BUT DRY. MODELS HAVE
SHOWN THAT WEDNESDAY AFTERNOON AND EVENING WILL HAVE AN INCREASED
CHANCE FOR RAIN, WITH THE BEST CHANCE IN LATE AFTERNOON EARLY
EVENING. SOME OTHER ENSEMBLES HAVE SHOWN A HIGH PRESSURE BUILDING
BACK IN FROM THE NORTH RESULTING IN A DRY FORECAST FOR WED THROUGH
LATE WEEK. OTHERS SHOW A FRONTAL BOUNDARY LIFTING FROM THE NORTH
BRINGING PRECIPITATION TO THE REGION LATE WEDNESDAY THROUGH THE END
OF THE WEEK. FOR NOW, KEPT SLIGHT CHANCE POPS FOR WEDNESDAY, CHANCE
POPS FOR WEDNESDAY NIGHT AND EARLY THURSDAY, THEN CAPS POPS AT 30
PERCENT THROUGH THE REST OF THE WEEK DUE TO LOW CONFIDENCE, AND
MODEL INCONSISTENCIES.
TEMPERATURES WILL SLOWLY BECOME NEAR NORMAL BY THE END OF THE WEEK
WITH HIGHS IN THE 50S EACH DAY (MAYBE EVEN 60S IN THE FAR SE) AND
LOWS RANGING FROM THE LOW 30S TO MID 40S.
AVIATION /18Z FRIDAY THROUGH WEDNESDAY/
AS OF 1214 PM FRIDAY...
MVFR CEILINGS WILL HANG ON A BIT LONGER ESPECIALLY AT KFAY/KRWI, BUT
SHOULD LIFT THROUGH ~20Z EVERYWHERE. SCATTERED SHOWERS (AND PERHAPS
A ROGUE LIGHTNING STRIKE) REMAIN POSSIBLE LATE THIS AFTERNOON AND
EVENING, WITH BEST CHANCES AT KINT/KGSO/KFAY (BUT CAN'T RULE OUT A
SHOWER AT KRDU/KRWI AS WELL). ANY LINGERING SHOWERS SHOULD DISSIPATE
BY ~03Z. AN ARCTIC FRONT WILL CLEAR THE AREA TONIGHT, PROMOTING A
BRIEF PERIOD OF 20 TO 25 KT GUSTS WHICH SHOULD SUBSIDE SOME TONIGHT
(ALTHOUGH WINDS AT THE SFC WILL CONTINUE TO STIR SOME). ADDITIONAL
20 KT GUSTS WILL BE POSSIBLE SATURDAY AFTERNOON UNDER OTHERWISE VFR
CONDITIONS.
LOOKING BEYOND 18Z SAT, VFR CONDITIONS WILL PREVAIL THROUGH TUE
UNDER COLD HIGH PRESSURE. -GIH
RAH WATCHES/WARNINGS/ADVISORIES
NONE.
SYNOPSIS...HARTFIELD
NEAR TERM...LUCHETTI
SHORT TERM...LUCHETTI
LONG TERM...CA
AVIATION...LUCHETTI/HARTFIELD
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