118
FXUS62 KRAH 191721
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
1220 PM EST TUE NOV 19 2024
SYNOPSIS
HIGH PRESSURE CENTERED OFFSHORE WILL EXTEND OVER THE SOUTHEAST COAST
THROUGH TODAY. AN UPPER LEVEL DISTURBANCE WILL PASS THROUGH THE
REGION EARLY WEDNESDAY. A SURFACE COLD FRONT WILL CROSS THE AREA
WEDNESDAY EVENING, USHERING IN COLDER AIR FOR LATE WEEK.
NEAR TERM /TODAY THROUGH TONIGHT/
AS OF 1027 AM TUESDAY...
NEGLIGIBLE CHANGES THIS MORNING. JUST UPDATED THE POP FORECAST TO
REFLECT LATEST HIGH-RES GUIDANCE, BUT CHANGES WERE MINIMAL COMPARED
TO PRIOR FORECAST.
AT THE SFC, LATEST ANALYSIS DEPICTED A WARM FRONT AND ASSOCIATED
PLUME OF DEEPER MOISTURE EXTENDING FROM THE DEEP SOUTH NORTH INTO
WESTERN TN/KY. DEW POINTS IN THIS AREA ARE IN THE LOWER TO MID 60S.
HERE LOCALLY, RESIDUAL COOL AND DRIER AIR LINGERS OVER CENTRAL NC.
WITH TIME TODAY, THE ANOMALOUS MOISTURE AXIS WILL SHIFT EAST NEARER
OUR AREA, AND EVENTUALLY SPREAD OVER CENTRAL NC TONIGHT. CAMS ARE IN
PRETTY GOOD AGREEMENT SUGGESTING THAT THE ONGOING CONVECTION TO OUR
SOUTH AND EAST SHOULD LARGELY DISSIPATE AS IT INTERACTS WITH OUR
RESIDUAL DRY AIR THROUGH THIS EVENING. CAN'T RULE OUT A FEW TRACE
REPORTS ACROSS OUR SOUTHERN PIEDMONT THIS AFTERNOON, BUT OVERALL
MUCH OF THE AREA SHOULD STAY DRY THROUGH THIS EVENING. DAYTIME HIGHS
SHOULD BE SIMILAR TO YESTERDAY, PEAKING IN THE UPPER 60S/LOWER 70S.
AS WE PIVOT TO THE OVERNIGHT PERIOD, THE SATURATION DEPTH SHOULD
DEEPEN WITH TIME, AS A FEW WEAK EMBEDDED MID-LEVEL PERTURBATIONS
SLIDE ACROSS THE SOUTHEAST. CAMS ARE IN A BIT OF DISAGREEMENT WITH
WRT TO HOW MUCH SHOWER COVERAGE THESE FEATURES MAY GENERATE (THE NAM
NEST IS MORE BULLISH THAN OTHER HREF MEMBERS). GIVEN SOME
UNCERTAINTY, DECIDED TO MAINTAIN MEDIUM TO HIGH CHANCE POPS (~30 TO
50 %) THROUGH 12Z WEDNESDAY. THE RANGE IN QPF DURING THIS TIME COULD
BE A FEW HUNDREDS OF AN INCH TO UPWARDS OF A FEW TENTHS. OTHERWISE
EXPECT WARM OVERNIGHT LOWS IN THE UPPER 50S.
SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/
AS OF 245 AM TUESDAY...
THE PREVIOUSLY FORECAST MARGINAL RISK OF SEVERE WEATHER HAS BEEN
ELIMINATED FOR WEDNESDAY.
EXPECT SOME LIGHT RAIN EARLY, THEN PARTLY SUNNY AND WARM. A CHANCE
OF SHOWERS WITH THE COLD FRONT LATE DAY.
TURNING SHARPLY COLDER AND BREEZY WEDNESDAY NIGHT, CLEARING.
A PRE-FRONTAL TROUGH WILL PUSH EAST THROUGH THE REGION
DURING THE MORNING. THIS WILL TAKE MUCH OF THE LOW LEVEL MOISTURE TO
THE COAST AND OFFSHORE BEFORE THE MAIN COLD FRONT ARRIVES LATE IN
THE DAY AND DURING THE EVENING. THERE WILL BE STRONG SHEAR, BUT VERY
LIMITED LIFT AND MOISTURE. A NARROW BAND OF SHOWERS IS POSSIBLE WITH
THE COLD FRONT, BUT EVEN ISOLATED THUNDERSTORMS SHOULD BE HARD TO
COME BY. DEW POINTS SHOULD FALL QUICKLY DURING THE AFTERNOON, FROM
NEAR 60 EARLY IN THE DAY INTO THE 40S/50S DURING THE AFTERNOON.
ASIDE FROM THE CHANCE OF SHOWERS WITH THE FRONT (THERE IS VERY
LITTLE SUPPORT FOR ADDITIONAL RAIN AFTER THE EARLY MORNING CHANCE OF
LIGHT RAIN EXITS EAST) HIGHS SHOULD REACH THE UPPER 60S TO LOWER
70S.
IT WILL TURN SHARPLY COLDER AND BREEZY WEDNESDAY NIGHT. THE SKIES
ARE EXPECTED TO BECOME MOSTLY CLEAR WITH THE LARGELY DOWNSLOPE FLOW
BEHIND THE COLD FRONT. LOWS WILL DIP INTO THE MID 30S TO LOWER 40S
NW TO SE.
LONG TERM /THURSDAY THROUGH MONDAY/
AS OF 148 AM TUESDAY...
* BRISK WINDS AND MUCH COOLER THU INTO SAT
* FROSTY MORNINGS FRI THROUGH SUN MORNING
* POSSIBLE FIRE DANGER CONCERNS THU AND FRI
NOT MUCH HAS CHANGED IN THE EXTENDED. AFTER THE COLD FRONTAL PASSAGE
WED NIGHT, STRONG WSW TO WNW FLOW WILL BE IN PLACE THU THROUGH SAT
AS SURFACE LOW PRESSURE PERSISTS ACROSS THE NE US AND HIGH PRESSURE
RESIDES OVER THE PLAINS. THE TIGHT PRESSURE GRADIENT COMBINED WITH
STRONG CAA WILL CREATE BRISK CONDITIONS WITH GUSTS OF 20-30 MPH, AT
TIMES TO 35 MPH. ALOFT, A VIGOROUS UPPER-TROUGH WILL SLOWLY ROTATE
FROM THE OH VALLEY AND MID-ATLANTIC INTO THE FAR NE US OVER THE
FIRST HALF OF THE WEEKEND. HIGHS THU THROUGH SAT ARE EXPECTED TO BE
SOME 5-12 DEGREES BELOW NORMAL IN THE LOW TO UPPER 50S, WITH
TEMPERATURES COOLEST ON FRI IN THE LOW/MID 50S.
MUCH OF THE GUIDANCE SHOWS THAT A RATHER STRONG VORT MAX ROTATES
AROUND THE BASE OF THE TROUGH THU NIGHT INTO MIDDAY FRI. AT THIS
TIME, ANOTHER SURGE OF CAA BUILDS SOUTH, REACHING -6 DEGC AT 850MB.
FORECAST SOUNDINGS FROM THE GFS SUGGEST SOME SATURATION IN THE
DENDRITIC GROWTH ZONE. WHILE STRONG DOWNSLOPE FLOW WILL DOMINATE,
WOULD NOT BE SURPRISED IF A FEW FLURRIES/GRAUPEL OCCUR OVER THE
PIEDMONT AS THE VORT MAX ROTATES THROUGH. OTHERWISE, IT WILL BE DRY.
SOME FROSTY MORNINGS APPEAR FAVORED FRI THROUGH SUN MORNING. MODELS
SUGGEST PERHAPS SOME WEAK DECOUPLING COULD OCCUR FRI MORNING TO
FAVOR LOW TO MID 30S. SIMILAR LOWS ARE EXPECTED SUN MORNING AS
SURFACE RIDGING LOOKS FAVORED, FAVORING IMPROVED RADIATIONAL COOLING
CONDITIONS.
SOME FIRE CONCERNS ARE POSSIBLE THU AND FRI. RELATIVE HUMIDITY
LEVELS MAY BE LOWEST ON THU BETWEEN THE UPPER 20S TO MID 30S AS
DEWPOINTS CRASH INTO THE 20S. COMBINED WITH WIND GUSTS BETWEEN 20-35
MPH, THIS COULD PROMPT AN INCREASED FIRE DANGER OR EVEN BRIEFLY
FLIRT WITH RED FLAG CONDITIONS.
THE PATTERN TURNS MORE SEASONAL TO ABOVE AVERAGE SUN AND MON AS
QUASI-ZONAL FLOW IS FAVORED IN THE GUIDANCE. HIGHS LOOK TO REBOUND
INTO THE LOW TO UPPER 60S BY MON. SOME ENSEMBLE DATA DOES SUGGEST
INCREASING WAA AT LOW-LEVELS MON WITH A POTENTIAL SYSTEM DEVELOPING
TO OUR WEST. THIS COULD PROMOTE SOME ISOLATED SHOWERS TO OUR NW. FOR
NOW, HAVE KEPT THE FORECAST DRY GIVEN THE UNCERTAINTY.
AVIATION /12Z TUESDAY THROUGH SATURDAY/
AS OF 635 AM TUESDAY...
VFR CONDITIONS WILL CONTINUE THROUGH THIS EVENING WITH PRIMARILY
HIGH CLOUDINESS. TERMINALS WILL SOCK IN LATE TONIGHT/EARLY WEDNESDAY
MORNING AS ANOMALOUS MOISTURE AND ASSOCIATED LIGHT RAIN SPILLS IN
FROM THE WEST. EXPECTING THESE SUB-VFR CEILINGS TO STAY LOCKED IN
THROUGH MID TO LATE WEDNESDAY MORNING WITH ADDITIONAL SHOWERS
POSSIBLE DURING THIS TIME.
BEYOND 18Z WEDNESDAY: A FEW ADDITIONAL SHOWERS AND PERHAPS AN
ISOLATED T-STORM WILL BE POSSIBLE WEDNESDAY AFTERNOON AS A STRONG
COLD FRONT APPROACHES. THE COLD FRONT WILL PASS THROUGH WEDNESDAY
NIGHT, AS DRY AND VFR CONDITIONS RETURN. STRONG POST-FRONTAL SFC
GUSTS OF 25 TO 30 KTS ARE LIKELY BOTH THURSDAY AND FRIDAY.
RAH WATCHES/WARNINGS/ADVISORIES
NONE.
SYNOPSIS...BADGETT
NEAR TERM...LUCHETTI
SHORT TERM...BADGETT
LONG TERM...KREN
AVIATION...LUCHETTI
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