673
FXUS62 KRAH 220821
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
321 AM EST MON DEC 22 2025
SYNOPSIS
CHILLY HIGH PRESSURE WILL BUILD ACROSS AND OFFSHORE THE SOUTHERN
MIDDLE ATLANTIC THROUGH TONIGHT, THEN TO NEAR BERMUDA ON TUESDAY. ON
ITS WESTERN PERIPHERY, A WARM FRONT WILL DEVELOP AND RETREAT NORTH
ACROSS THE CAROLINAS ON TUESDAY. THE FRONT WILL THEN SETTLE BRIEFLY
SOUTHWARD INTO THE SAVANNAH BASIN LATE WEDNESDAY INTO WEDNESDAY
NIGHT, WHEN HIGH PRESSURE WILL MIGRATE ACROSS THE MIDDLE ATLANTIC.
NEAR TERM /THROUGH TONIGHT/
AS OF 250 AM MONDAY...
BEHIND A SHORTWAVE TROUGH NOW MOVING OFF THE COAST OF THE NRN MIDDLE
ATLANTIC AND NEW ENGLAND, 00Z-OBSERVED, 500 MB HEIGHT RISES OF 50-
100 METERS OVER THE MID AND UPR MS VALLEY LAST EVENING WILL PROGRESS
ACROSS THE MIDDLE ATLANTIC TODAY, THEN OFFSHORE TONIGHT. STRONG AND
TROPOSPHERIC-DEEP SUBSIDENCE WILL RESULT AND MAXIMIZE OVER CNTL NC
EARLY TODAY. A SUB-TROPICAL HIGH SPANNING FROM NRN MX TO THE NRN
GULF WILL OTHERWISE REMAIN IN PLACE AND DIRECT NWLY TO WNWLY MID/UPR-
LEVEL FLOW FROM THE GREAT PLAINS TO THE EAST COAST, ATOP
STRENGTHENING SWLY TO WSWLY FLOW THROUGH THE LOW AND MID-LEVELS.
ASSOCIATED, STRENGTHENING AND STRONGLY-VEERING WIND PROFILES AND
WAA, AND QG-FORCING FOR ASCENT, WILL RESULT AND PROGRESS ACROSS THE
OH VALLEY AND MIDDLE ATLANTIC, WITH GLANCING INFLUENCE OVER CNTL NC
TONIGHT.
AT THE SURFACE, 1035 MB, CP HIGH PRESSURE NOW CENTERED OVER WV WILL
PROGRESS ACROSS AND OFFSHORE THE SRN MIDDLE ATLANTIC, WITH
ASSOCIATED MAINLY LIGHT AND VEERING WINDS FROM NLY/NELY THIS MORNING
TO ELY/SELY THIS AFTERNOON.
AFTER THE AFOREMENTIONED SUBSIDENT, AND CLEAR MOST OF MONDAY, A BAND
OF MID/HIGH-LEVEL CEILINGS WILL STREAM OVERHEAD THIS EVENING. IT
WILL BE FOLLOWED BY 700 MB-CENTERED LIFT AND SATURATION, AND
ASSOCIATED ALTOCUMULUS THAT MAY INCLUDE PATCHY LIGHT RAIN OR
SPRINKLES, AFTER 06Z TUE. IT WILL OTHERWISE BE SEASONABLE AND A
LITTLE BELOW AVERAGE TODAY, WITH HIGHS IN THE MID 40S TO LWR 50S,
THEN A LITTLE ABOVE AVERAGE AND MOSTLY IN THE LWR-MID 30S TONIGHT.
SHORT TERM /TUESDAY AND TUESDAY NIGHT/
AS OF 320 AM MONDAY...
A RIDGE WILL AMPLIFY NWD AND THROUGH THE PLAINS, FROM A SUB-TROPICAL
HIGH THAT WILL REMAIN CENTERED OVER THE NRN GULF. A DOWNSTREAM AND
UNDERLYING LOW-MID-LEVEL WAA REGIME WILL OTHERWISE PROGRESS ACROSS
AND OFFSHORE THE MIDDLE ATLANTIC.
AT THE SURFACE, HIGH PRESSURE WILL PROGRESS QUICKLY EWD ACROSS
BERMUDA, WHILE AN AREA OF LOW PRESSURE WILL DEEPEN ACROSS AND
OFFSHORE SRN NEW ENGLAND AND THE NRN MIDDLE ATLANTIC. IN
STRENGTHENING SWLY TO WSWLY FLOW BETWEEN THE TWO, A WARM FRONT WILL
DEVELOP AND RETREAT RAPIDLY NEWD ACROSS THE CAROLINAS AND VA ON TUE,
WITH ASSOCIATED SWLY SURFACE WINDS THAT WILL GUST BETWEEN 20-30 MPH
DURING THE AFTERNOON. TRAILING THE FAST-MOVING AND DEEPENING LOW, A
COLD FRONT WILL SETTLE SWD ACROSS VA TUE NIGHT.
MULTI-LAYERED, 925 MB AND 700 MB-CENTERED OVERCAST EARLY TUE, AND
PATCHY LIGHT RAIN OR SPRINKLES, WILL MOVE EWD AND OFFSHORE THROUGH
THE AFTERNOON, WITH ASSOCIATED WEST TO EAST (PARTIAL) CLEARING OVER
CNTL NC. AREAS OF STRATOCUMULUS MAY PERSIST THROUGH THE AFTERNOON-
EVENING ESPECIALLY OVER SRN NC, HOWEVER, UNTIL WINDS IN THAT LAYER
(BETWEEN 850-925 MB) VEER TO A MORE NLY COMPONENT AND DIRECT DRIER
AND SLIGHTLY COOLER AIR INTO CNTL NC THROUGH WED MORNING, WITH
CLEARING. TEMPERATURES WILL TREND WELL ABOVE AVERAGE AND INTO THE
UPR 50S TO LWR 60S ON TUE, FOLLOWED BY LOWS TUE NIGHT IN THE 40S.
LONG TERM /WEDNESDAY THROUGH SUNDAY/
AS OF 229 AM MONDAY...
UPPER PATTERN: AN ANOMALOUS MID/UPPER RIDGE WILL REMAIN ANCHORED
OVER THE CENTRAL US THROUGH LATE THIS WEEK GENERATING PRIMARILY
WNWLY FLOW ALOFT OVER CENTRAL NC. THE RIDGE WILL DE-AMPLIFY LATE
THURSDAY AS A SHORT-WAVE MOVES EAST ACROSS THE OHIO VALLEY FRIDAY
INTO SATURDAY. A POTENTIALLY DEEPER LONG-WAVE TROUGH MAY PUSH EAST
ACROSS THE US SATURDAY INTO SUNDAY.
CHRISTMAS EVE AND CHRISTMAS DAY: HIGH PRESSURE OVER NEW ENGLAND WILL
EXTEND GENERALLY ENELY TURNING ESELY FLOW OVER CENTRAL NC WEDNESDAY.
EXPECT DRY WEATHER WITH ABOVE AVERAGE HIGHS IN THE MID TO UPPER 60S.
THE CENTER OF THE HIGH WILL DRIFT OVER THE MOUTH OF THE CHESAPEAKE
WEDNESDAY NIGHT AND AS SUCH RADIATIVE COOLING WILL BE MOST FAVORABLE
OVER THE COASTAL PLAIN. EXPECT OVERNIGHT LOWS TO DIP INTO THE MID
30S ALONG THE I-95 CORRIDOR WITH LOWER 40S EXPECTED ELSEWHERE.
THE HIGH WILL SHIFT OFFSHORE ON THURSDAY PROMOTING SSWLY RETURN FLOW
AND TEMPERATURES SOARING WELL ABOVE NORMAL INTO UPPER 60S/LOWER 70S.
EXPECT GENERALLY DRY WEATHER THURSDAY WITH INCREASING CLOUDINESS
THURSDAY EVENING WITH LOWS IN THE UPPER 40S/LOWER 50S.
FRIDAY THROUGH MONDAY: PERSISTENT SSWLY FLOW ON FRIDAY WILL HELP
TEMPERATURES SOAR TO ~20 DEGREES ABOVE NORMAL INTO THE LOWER TO MID
70S. AS THE AFOREMENTIONED SHORT-WAVE TRAVERSES THE OHIO VALLEY,
MARGINAL MID-LEVEL HEIGHT FALLS WILL SPREAD EAST ACROSS THE MID-
ATLANTIC. THE STRONGEST UPPER FORCING AND DEEPEST MOISTURE APPEARS
TO STAY TO OUR NORTH, SO AS OF NOW DECIDED TO MAINTAIN A DRY
FORECAST. HOWEVER, WOULD NOT BE SURPRISED IF LIGHT RAIN TRICKLES
ACROSS THE NC/VA BORDER FRIDAY AFTERNOON/EVENING. OTHERWISE, EXPECT
GUSTS OF UP TO 20 TO 25 MPH AT TIMES FRIDAY AFTERNOON.
IN WAKE OF THE PASSING SHORT-WAVE WE'LL SEE SUBSIDENCE AND DRYING ON
SATURDAY WITH A BIT COOLER HIGHS IN THE UPPER 60S. BY SUNDAY,
MODELS ARE IN A BIT OF DISAGREEMENT WITH HOW TO HANDLE A POTENTIAL
DEEPER LONG-WAVE TROUGH AND ASSOCIATED PRECIPITATION. THE ECMWF IS
MUCH MORE AMPLIFIED THAN THE GFS AND THUS PROVIDES A WETTER SOLUTION
(EPS VS. GEFS PAINTS A SIMILAR SPLIT). WE'LL CONTINUE TO WATCH HOW
THE GUIDANCE UNFOLDS THE NEXT SEVERAL DAYS, BUT FOR NOW KEPT SLIGHT
CHANCE TO LOW END CHANCE POPS IN THE FORECAST FOR SUNDAY. A POST-
FRONTAL COOL DOWN THEN LOOKS POSSIBLE NEXT MONDAY.
AVIATION /06Z MONDAY THROUGH FRIDAY/
AS OF 120 AM MONDAY...
CONTINENTAL POLAR HIGH PRESSURE AND ASSOCIATED VERY DRY AIR WILL
FAVOR VFR CONDITIONS IN CNTL NC THROUGH 06Z TUE AND MAINLY LIGHT AND
VEERING WINDS FROM NLY THIS MORNING TO ELY OR SELY THIS AFTERNOON.
THE EXCEPTION TO THOSE LIGHT AND VEERING/VARIABLE WINDS WILL BE A
SHORT PERIOD OF SLIGHTLY STRONGER NELY AND GUSTY ONES INTO THE TEENS
KTS WITH HEATING/MIXING AND INITIAL DEEPENING OF THE BOUNDARY LAYER
BETWEEN 13-16Z AT RWI AND FAY.
OUTLOOK: SWLY RETURN FLOW WILL THEN DEVELOP AND STRENGTHEN AROUND
THE HIGH AS IT DRIFTS TO NEAR BERMUDA ON TUE, WHICH WILL PROMOTE
CHANCES ON TUE OF LOW-LEVEL WIND SHEAR OVER THE PIEDMONT IN THE
MORNING, MVFR RANGE CLOUD BASES AND POSSIBLE CEILINGS MORNING
THROUGH EARLY AFTERNOON, AND GUSTY SWLY WINDS INTO THE 20S KTS
DURING THE AFTERNOON. A LITTLE LIGHT RAIN FROM VFR CEILINGS BETWEEN
4-6 THOUSAND FT MAY ALSO RESULT FROM MID-LEVEL LIFT THAT WILL
CONCURRENTLY OVERSPREAD NC. MVFR CEILINGS WILL BE POSSIBLE AGAIN
EARLY THU, ESPECIALLY OVER THE WRN PIEDMONT.
RAH WATCHES/WARNINGS/ADVISORIES
NONE.
SYNOPSIS...MWS
NEAR TERM...MWS
SHORT TERM...MWS
LONG TERM...LUCHETTI
AVIATION...MWS
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