191
FXUS62 KRAH 181948
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
247 PM EST MON NOV 18 2024
SYNOPSIS
OFFSHORE HIGH PRESSURE WILL EXTEND ACROSS THE SOUTH ATLANTIC STATES
AHEAD OF A STRONG COLD FRONT THAT WILL MOVE THROUGH THE REGION
WEDNESDAY NIGHT. COLDER CONDITIONS WILL FOLLOW FOR LATE WEEK.
NEAR TERM /TODAY AND TONIGHT/
AS OF 1006 AM MONDAY...
..WARM AND CONTINUED DRY
DOWNSTREAM OF THE VIGOROUS, NEGATIVELY
TILTED SHORTWAVE TROUGH EJECTING NORTHEASTWARD THROUGH THE CENTRAL
PLAINS, STRONG SUB-TROPICAL HIGH PRESSURE WILL PREVAIL OVER THE SE
US THROUGH EARLY TUESDAY. INTERVALS OF CIRRUS WILL CONTINUE TO SPILL
ATOP THE RIDGE, ESPECIALLY ACROSS THE NORTHERN HALF OF THE FORECAST
AREA. UNDER PARTLY TO MOSTLY SUNNY SKIES HIGHS TODAY A FEW DEGREES
WARMER THAN YESTERDAY, WITH MOST PLACES WARMING INTO THE UPPER 60S
TO LOWER 70S, WHICH IS 5-10 DEGREES ABOVE THE 30 YR NORMS.
OVERNIGHT, HIGH CLOUDS/CIRRUS SHOULD BE MORE PERVASIVE AND OPAQUE
ACROSS NORTHERN AND CENTRAL NC, WHICH SHOULD KEEP THE BEST CHANCE
FOR FOG ACROSS SOUTHERN COUNTIES. MILD OVERNIGHT LOWS IN THE MID
40S TO LOWER 50S, WHICH IS 8 TO 15 DEGREES ABOVE NORMAL.
SHORT TERM /TUESDAY AND TUESDAY NIGHT/
AS OF 247 PM MONDAY...
THE UPPER AND SFC RIDGE AXIS WILL GRADUALLY MOVE EAST AND OFFSHORE
THROUGH THE DAY. SUBSEQUENT SW FLOW ON THE BACK SIDE OF THE RIDGE
WILL RESULT IN INCREASING MID AND HIGH CLOUDINESS ACROSS OUR AREA AS
THE DAY PROGRESSES, BUT ESP IN THE LOWER LEVELS LATER IN THE
AFTERNOON AND EVENING PER LATEST FORECAST SOUNDINGS FOR LOCATIONS
ACROSS OUR AREA. WITH AN AIRMASS SIMILAR TO TODAY, AND FILTERED
SUNSHINE, LOOK FOR HIGHS TUESDAY AFTERNOON WITHIN A COUPLE DEGREES
OF TODAY'S HIGHS.
AS THE UPPER TROUGH CONTINUES TO APPROACH TUESDAY NIGHT, INCREASED
FLOW AND WAA FROM THE SFC UP TO 5K FT, AND RESULTING LIFT IN THE LOW
LEVELS, WILL WARRANT GRADUALLY INCREASING POPS FROM SUNSET TUESDAY
ONWARD, BUT ESP AFTER MIDNIGHT AS THE WAA IS MAXIMIZED. LOWS
TUESDAY NIGHT WILL BE ABOUT 5-10 DEG WARMER THAN TONIGHT GIVEN
INCREASED CLOUD COVER AND WAA... MID 50S ACROSS MUCH OF CENTRAL NC.
LONG TERM /WEDNESDAY THROUGH SUNDAY/
AS OF 202 AM MONDAY...
* STRONG COLD FRONTAL PASSAGE WED NIGHT, WITH A CONDITIONAL ISOLATED
SEVERE THREAT
* MUCH COLDER THU INTO SAT, WITH WSW TO WNW WINDS BRISK AT TIMES OF
25-35 MPH
WE CONTINUE TO TRACK A STRONG COLD FRONTAL PASSAGE SET TO MOVE
THROUGH WED NIGHT. MUCH OF THE GUIDANCE REMAINS IN GOOD AGREEMENT
THAT THE FRONT MOVES THROUGH BETWEEN 6 PM AND 1 AM. A VIGOROUS MID-
LEVEL SHORTWAVE TROUGH OVER THE UPPER MS VALLEY AND GREAT LAKES IS
FORECAST TO TRACK INTO THE OH VALLEY AND MID-ATLANTIC BY EARLY THU.
MOST GUIDANCE SUGGESTS SOME LIGHT RAIN MAY PERSIST INTO LATE MORNING
ALONG/EAST OF US-1 TIED TO WEAK ISENTROPIC ASCENT IN THE 700-500 MB
LAYER. THIS IS THEN FORECAST TO MOVE OUT BY MIDDAY, OWING TO ONE
LAST MILD DAY IN THE UPPER 60S TO LOW 70S.
AS THE FRONT APPROACHES FROM THE WEST WED EVENING, STRONG HEIGHT
FALLS AND DPVA WILL OVERSPREAD THE REGION. THERE STILL APPEARS TO BE
A SHORT WINDOW OF TIME WHEN SHEAR/INSTABILITY COULD OVERLAP AHEAD OF
THE FRONT TO FAVOR A CONDITIONAL SEVERE THREAT. WHAT REMAINS
CONDITIONAL IS THE AMOUNT OF INSTABILITY, AS WELL AS THE FACT THAT
THE DEEPER MOISTURE WILL SHIFT TOWARD THE COAST BY EVENING, LEAVING
A POTENTIAL LACK OF OVERLAP OF KINEMATICS AND THERMODYNAMICS. HIGH-
END AMOUNTS OF MLCAPE APPROACH ~ 500 J/KG, WITH LOW END AMOUNTS OF A
FEW HUNDRED J/KG. SHEAR IS NOT LACKING, WITH 50-60 KT IN THE 0-6 KM
LAYER, ~ 30 KT OF 0-3 KM, AND 20-25 KT OF 0-1 KM. IT WOULD APPEAR
MOST GUIDANCE SHOWS A POSSIBLE ISOLATED/BROKEN LINE OF SHOWERS
TRACKING EAST BETWEEN ABOUT 6 PM AND MIDNIGHT, THOUGH WHETHER ANY
STORMS COULD BECOME SURFACE BASED IS STILL UNCLEAR. A LOOK AT HIGH-
RES CAMS IN THE COMING DAYS WILL BE HELPFUL TO BETTER ASSESS THE
ENVIRONMENT.
IT STILL APPEARS MUCH COLDER THU INTO SAT AS THE VIGOROUS TROUGH
ROTATES CYCLONICALLY OVER THE MID-ATLANTIC AND NE US INTO SAT. HIGH
TEMPERATURES THU-SAT WILL BE SOME 15-20 DEGREES COLDER COMPARED TO
WED IN THE LOW TO MID/UPPER 50S, COOLEST ON FRI WITH STRONG CAA IN
PLACE. BRISK WSW TO WNW WINDS WILL BE IN PLACE AS WELL, GUSTING AT
TIMES TO BETWEEN 25 AND 35 MPH, HIGHEST ON FRI. GUIDANCE SHOWS THAT
RIDGING OR QUASI-ZONAL FLOW MAY BUILD IN SUN, WHICH SHOULD ALLOW A
SLIGHT MODERATION IN THE AIRMASS WITH MID 50S TO NEAR 60. LOWS FRI
AND SUN MORNING COULD APPROACH FROST/FREEZE POTENTIAL IN THE LOW TO
MID 30S, WITH PERHAPS THE BEST CHANCE SUN MORNING WITH HIGH PRESSURE
BUILDING IN WITH LIGHTER SFC WINDS.
AVIATION /18Z MONDAY THROUGH SATURDAY/
AS OF 1250 PM MONDAY...
HIGH CLOUDS/CIRRUS WILL CONTINUE TO OVERSPREAD THE AREA THROUGH THE
PERIOD. AREAS OF FOG ARE POSSIBLE AGAIN LATE TONIGHT/EARLY TUESDAY,
WITH THE HIGHEST PROBABILITIES DEPICTED INVOF KINT, KGSO, AND KFAY.
WINDS WILL REMAIN LIGHT AND VARIABLE, AND WILL BECOME SWLY TUESDAY
AFTERNOON.
OUTLOOK: CEILINGS WILL LOWER TO SUB-VFR FROM WEST TO EAST TUESDAY
AFTERNOON THROUGH THE EVENING AND OVERNIGHT HOURS. LIFR TO IFR
RESTRICTIONS ARE EXPECTED TO DEVELOP AT ALL TAF SITES TUESDAY NIGHT
AND WEDNESDAY MORNING AS RAIN SHOWERS SPREAD EAST THROUGH THE AREA.
FOLLOWING A POTENTIAL MIDDAY LULL, ANOTHER ROUND OF SHOWERS AND
PERHAPS EVEN A FEW THUNDERSTORMS ARE POSSIBLE WEDNESDAY AFTERNOON AND
EVENING WITH RESTRICTIONS REMAINING SUB-VFR UNTIL THE LATE AFTERNOON
AND EVENING. A DEEPENING AREA OF LOW PRESSURE INVOF THE GREAT LAKES
WILL YIELD FREQUENT GUSTS OF 20 TO 30 KTS THURSDAY AND AGAIN ON
FRIDAY.
RAH WATCHES/WARNINGS/ADVISORIES
NONE.
SYNOPSIS...BADGETT
NEAR TERM...CBL
SHORT TERM...NP
LONG TERM...KREN
AVIATION...CBL
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page