-- Discussion containing changed information from previous version are highlighted. --
000
FXUS62 KRAH 041931 RRA
AFDRAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
231 PM EST WED DEC 4 2013

.SYNOPSIS...AN UPPER LEVEL DISTURBANCE CROSSING THE AREA WILL TRACK
TO OUR NORTHEAST THIS MORNING... AS A WARM FRONT MOVES NORTHWARD
THROUGH THE AREA. A WARM AND MOIST SOUTHERLY FLOW BEHIND THIS WARM
FRONT WILL PERSIST THROUGH FRIDAY... RESULTING IN ABOVE NORMAL
TEMPERATURES. A COLD FRONT WILL MOVE IN FROM THE WEST EARLY SATURDAY.

&&

.NEAR TERM /TODAY THROUGH TONIGHT/...
AS OF 230 PM WEDNESDAY...

THE SHOWER ACTIVITY FROM THIS MORNING CONTINUES TO MOVE OFF THE CAROLINA
COAST AS MODEST HEIGHT RISES MOVE IN FROM THE WEST. SOUTHERLY FLOW WILL
PROVIDE TEMPERATURES IN THE LOWER TO UPPER 60S NW TO SE... DESPITE MOSTLY
CLOUDY CONDITIONS PERSISTING THROUGH THE REST OF THE DAY.

WITH THE MOIST AIRMASS IN PLACE... ANOTHER ROUND OF LOW CLOUDS...
AND POSSIBLY AREAS OF FOG... WILL FORM ACROSS THE AREA OVERNIGHT. AN
AREA OF ISENTROPIC LIFT ACROSS THE WESTERN HALF OF THE STATE MAY
RESULT IN SOME DRIZZLE. TEMPERATURES WILL REMAIN MILD...IN THE MID
50S.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY/...
AS OF 231 PM WEDNESDAY...

HIGH PRESSURE WILL REMAIN ACROSS THE WESTERN ATLANTIC... AS A COLD
FRONT SLOWLY APPROACHES FROM THE WEST. THE AREA WILL REMAIN IN THE
WARM SECTOR THROUGH FRIDAY. LOW LEVEL THICKNESSES ON THURSDAY WILL
RISE 20M OVER TODAY... AND THAT WILL PUSH HIGHS INTO THE LOW TO MID
70. THE PRESSURE GRADIENT WILL TIGHTEN IN ADVANCE OF THE APPROACHING
COLD FRONT... AND WINDS ON WILL GUST DURING THE AFTERNOON HOURS 15-
20 KTS. LOWS ON THURSDAY IN THE LOW TO MID 60S. FRIDAY WILL BE A FEW
DEGREES WARMER... WITH HIGHS IN THE MID TO UPPER 70S. RAIN SHOWERS
MAY BEGIN TO MOVE INTO THE WESTERN PIEDMONT FRIDAY AFTERNOON... WITH
RAIN MOVING IN OVERNIGHT. FRONT WILL BEGIN TO MOVE ACROSS THE REGION
OVERNIGHT... AND UNFAVORABLE DIURNAL TIMING WILL LIMIT INSTABILITY.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 310 AM WEDNESDAY...

AMPLIFICATION OF THE LONGWAVE PATTERN...WITH A TROUGH OVER THE
WESTERN US AND A RIDGE OVER THE WESTERN ATLANTIC...WILL MAINTAIN
SOUTHWESTERLY FLOW ALOFT OVER THE SOUTHEAST US AND MID-ATLANTIC
STATES THROUGH THE WEEKEND.  A FRONTAL ZONE WEST OF THE MOUNTAINS
WILL MOVE SLOWLY EAST FRIDAY...AWAITING A KICK FROM A SHORTWAVE
LIFTING OUT OF THE SOUTHERN PLAINS.  AHEAD OF THE FRONT...A STEADY
SOUTHWESTERLY LOW-LEVEL FLOW WILL PUSH THICKNESSES ABOVE 1380M
FRIDAY MORNING...WHICH IS 60M ABOVE NORMAL AND CORRESPONDS TO HIGHS
IN THE MID 70S TO AROUND 80 UNDER FULL SUN.  WHILE RH CROSS SECTIONS
SUGGEST THERE WILL BE PLENTY OF MID AND HIGH CLOUDS IN THE FAST FLOW
ALOFT...WARM ADVECTION AND SOME POTENTIAL FOR BREAKS OR THINNING OF
CLOUD COVER SHOULD SHOULD ALLOW TEMPS TO REACH THE 75-80
RANGE...WHICH STATISTICAL GUIDANCE ALSO SUPPORTS.

GUIDANCE IS IN DECENT AGREEMENT REGARDING THE FRONTAL PASSAGE LATE
FRIDAY NIGHT AND EARLY SATURDAY...THOUGH THE 00Z ECMWF CONTINUES TO
WAIVER BETWEEN A 06-12Z AND 12-18Z FROPA. THE FRONT WILL BE
ACCOMPANIED BY MOSTLY ANAFRONTAL PRECIP WITH INCREASING ISENTROPIC
LIFT AS THE FRONT SURGES SOUTH BENEATH THE SOUTHWESTERLY FLOW JUST
ABOVE THE SURFACE.  A LULL...OR DIMINISHING TREND IN PRECIP RATES IS
POSSIBLE SATURDAY AFTERNOON/EVENING BEFORE THE LOW-LEVEL FLOW BEGINS
TO ACCELERATES ONCE AGAIN AHEAD OF ANOTHER WAVE EJECTING OUT OF THE
SOUTHERN PLAINS.  THE BEST PERIOD OF ISENTROPIC ACCENT AND
WIDESPREAD PRECIP SHOULD COME SATURDAY NIGHT INTO SUNDAY.  AT THE
SAME TIME..AN ARCTIC HIGH IS FORECAST TO BUILD ACROSS THE GREAT
LAKES TO THE NORTHEAST US AND SUPPLY A SECONDARY SURGE OF COLD AIR
FROM THE NORTH.  THE OVERALL PATTERN SUPPORTS AT LEAST A BRIEF
PERIOD OF FREEZING RAIN IN THE NORTHWEST PIEDMONT...THOUGH MODELS
HAVE TREND SLIGHTLY WEAKER WITH THE SURFACE HIGH (DOWN TO 1037MB)
OVER THE PAST FEW RUNS AND CONSEQUENTLY KEEP THE WETBULB FREEZING
LINE JUST OUTSIDE OF THE NORTHWEST PIEDMONT. THIS WILL NEED TO BE
MONITORED WITH SUBSEQUENT MODEL RUNS.  ONCE THE RAIN AND COLD AIR
DAMMING SET IN ON SATURDAY...TEMPS WILL LIKELY REMAIN RELATIVELY UN
CHANCED THROUGH SUNDAY...WITH MID 30S TO LOWER 40S ACROSS THE CWA.

FOR MONDAY AND TUESDAY... A SURFACE LOW ASSOCIATED WITH THE
SHORTWAVE MENTION ABOVE IS PROGGED TO LIFT TOWARD THE GREAT LAKES
MONDAY...PUTTING CENTRAL NC BACK IN THE WARM SECTOR.  WILL SHOW A
MINIMUM IN POPS ON MONDAY AS THE FOCUS OF FORCING SHIFTS BACK WEST
OF THE MOUNTAINS BEFORE THE COLD FRONT SWEEPS ACROSS THE CWA MONDAY
NIGHT OR TUESDAY.  GUIDANCE IS LIKELY TOO HIGH REGARDING TEMPS
MONDAY GIVEN THE PRECEDING COLD AIR DAMMING... BUT SO WILL STICK
WITH COOLER READINGS IN THE LOWER 50S TO LOWER 60S.

&&

.AVIATION /18Z WEDNESDAY THROUGH SUNDAY/...
AS OF 1250 PM WEDNESDAY...

ADVERSE AVIATION CONDITIONS WILL REMAIN ACROSS THE AREA FOR MUCH OF
THE 24 HOUR PERIOD. GENERALLY IFR TO MVFR CONDITIONS ACROSS THE AREA
WILL LIKELY ONCE AGAIN RETURN TO IFR/LIFR TONIGHT AS LOW STRATUS AND
FOG DEVELOPS IN THE INCREASINGLY MOIST AIRMASS. CONDITIONS WILL
BEGIN TO IMPROVE BY LATE MORNING TO MVFR CONDITIONS... AND LIKELY
VFR THURSDAY AFTERNOON... AS SW WINDS GUST TO 15-20 KTS.

SUB-VFR CONDITIONS ARE LIKELY FRIDAY THROUGH THE WEEKEND AS A COLD
FRONT APPROACHES... WITH UNSETTLED CONDITIONS AND THE CHANCE FOR
RAIN PERSISTING THROUGH THE WEEKEND.

&&

.CLIMATE...

RECORD HIGH TEMPERATURES FOR DECEMBER 6TH:

GSO... 76 SET IN 1998
RDU... 80 SET IN 1998
FAY... 80 SET IN 1998

&&

.RAH WATCHES/WARNINGS/ADVISORIES...
NONE

&&

$$

SYNOPSIS...HARTFIELD
NEAR TERM...SEC
SHORT TERM...SEC
LONG TERM...SMITH
AVIATION...SEC
CLIMATE...RAH