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000
FXUS62 KRAH 070843
AFDRAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
345 AM EST SAT DEC 7 2013

.SYNOPSIS...
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A STRONG COLD FRONT WILL PUSH SOUTH OF THE AREA THIS
MORNING. COLD ARCTIC HIGH PRESSURE WILL THEN BUILD INTO THE REGION
TONIGHT AND DURING THE DAY ON SUNDAY. ANOTHER COLD FRONT IS EXPECTED
TO CROSS THE AREA TUESDAY WITH RELATIVELY COLD HIGH PRESSURE
BUILDING BACK IN THROUGH THURSDAY.
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&&

.NEAR TERM /TODAY/...
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AS OF 130 AM SATURDAY...

NORTHERN EDGE OF COLD FRONT STARTING TO SURGE SOUTH FROM SOUTHERN
VIRGINIA AND MODEL TIMING LOOKS TO BE ON TRACK...SCHEDULED TO SLIP
SOUTH OF THE AREA BY MID MORNING ~15Z. AS THE SUN RISES... ANA-
FRONTAL PRECIP SHIELD SHOULD BE FAIRLY WIDESPREAD SOUTH AND EAST OF
THE TRIANGLE...DIMINISHING BY MIDDAY WITH PERHAPS SOME LINGERING
LIGHT RAIN/DRIZZLE WITHIN THE CONTINUED SWLY FEED ACROSS THE FAR
SOUTHEASTERN ZONES(SANDHILLS/SOUTHERN COASTAL PLAIN).
OTHERWISE...STILL EXPECT THERE TO BE A GOOD 12-15 HOUR LULL IN
PRECIP OVER THE WESTERN AND CENTRAL PIEDMONT OWING TO BETTER LOW-
LEVEL WESTERLY FEED ADVECTING DRIER INTO THE AREA AS STRONG ARCTIC
HIGH PRESSURE OVER THE COUNTRYS MID-SECTION BUILDS EASTWARD INTO THE
REGION .

TEMPERATURES WILL STEADILY FALL FROM MORNING HIGHS...WITH EVERYONE
IN THE 40S BY THE AFTERNOON...BUT FEELING MUCH CHILLIER WITH 6MB
PRESSURE RISES RESULTING IN A STEADY 10 TO 15 MPH NORTHERLY BREEZE.
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&&

.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
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AS OF 300 AM SATURDAY...

FORECAST REMAINS ON TRACK WITH POTENTIAL FOR A TENTH TO TWO-TENTHS
OF AN INCH OF ICE ACROSS THE FAR NORTHWEST/NORTHERN PIEDMONT OF
NORTH CAROLINA LATE TONIGHT THROUGH SUNDAY EVENING. PRIOR WINTER
STORM WATCH WILL BE UPGRADED TO A WINTER STORM WARNING WITH AN
ISSUANCE OF A WINTER STORM ADVISORY FOR THE THE NEXT ROW OF COUNTIES
SOUTH AND EAST OF THE WARNING AREA.

COLD DRY ARCTIC AIR WILL CONTINUE TO TO SURGE EAST-SOUTHEASTWARD
INTO THE CAROLINAS SATURDAY NIGHT/EARLY SUNDAY AS A STRONG 1035-1040
MB HIGH PRESSURE OVER THE UPPER MID WEST/MIDDLE MS VALLEY BUILDS
INTO THE MID-ATLANTIC STATES. JUST ABOVE THIS SHALLOW LAYER OF
ARCTIC AIR...A 30-35KT SWLY LOW-LEVEL JET WITHIN A PROMINENT 6-8C
WARM NOSE WILL PROMOTE THE DEVELOPMENT OF RAIN FROM SOUTH TO NORTH
BETWEEN 03 TO 09Z. BY DAYBREAK SUNDAY...AIDED BY WET-BULB COOLING AT
THE ONSET OF PRECIP...CONTINUED CAA WILL SEND TEMPERATURES FALLING
INTO THE LOWER 30S NORTH TO UPPER 30S SOUTH...BRINGING A THREAT OF
FREEZING RAIN TO THE NORTHERN PIEDMONT COUNTIES.

AS THE ARCTIC HIGH BECOMES ENTRENCHED EAST OF THE APPALACHIANS
DURING THE DAY ON SUNDAY...TEMPERATURES MAY ACTUALLY FALL A DEGREE
OR TWO SUNDAY AFTERNOON...LOCKING IN THE NEAR FREEZING TEMPERATURES
IN THE HEART OF THE WEDGE OVER THE WESTERN/CENTRAL PIEDMONT AND
POTENTIALLY RESULTING IN A 6 TO 12 HOUR WINDOW OF FREEZING PRECIP
WITH ISENTROPIC ASCENT MAXIMIZED OVER THE AREA THROUGH THE DAYTIME
HOURS. LIQUID QPF AMOUNTS CONTINUE TO RANGE FROM 0.20 TO 0.40 OVER
THE FAVORED PIEDMONT DAMMING REGION WITH A POTENTIAL FOR HALF OR
THREE-QUARTERS TO FALL AS FREEZING RAIN . WITH A WARM WET
GROUND...THE GREATEST IMPACTS ARE EXPECTED TO OCCUR ON ELEVATED
SURFACES (ESPECIALLY TREES AND POWER LINES).

BY LATE SUNDAY EVENING....AS THE LLJ AND ASSOCIATED ISENTROPIC LIFT
WELL NORTH OF OUR REGION AND THE PARENT HIGHS SHIFTS OFFSHORE...
PRECIPITATION WILL TAPER TO FREEZING DRIZZLE...AND THEN DRIZZLE OVER
THE NW PIEDMONT AS TEMPERATURES WARM TO THE MIDDLE 30S NW PIEDMONT
TO MIDDLE 40S SE BY DAYBREAK MON.
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&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
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AS OF 300 AM SATURDAY...

MONDAY THROUGH TUESDAY NIGHT...APPROACH OF A COLD FRONT WILL ERODE
THE CAD WITH STRONGER...DEEPER SOUTHWEST FLOW. THE RESULTING LOSS OF
STRONG ISENTROPIC LIFT WILL ALLOW FOR A RELATIVE LULL IN THE POPS ON
MONDAY. ROLLER COASTER RIDE ON TEMPS WILL CONTINUE...WITH HIGHS
REBOUNDING MONDAY IN THE STRONG WARM AIR ADVECTION REGIME...WITH THE
SOUTHEAST PERHAPS APPROACHING 70...WHILE THE MORE DEEPLY ENTRENCHED
NORTHEAST SHOULD REACH 50...PERHAPS HIGHER IF THE COOL AIR IS
SCOURED EARLY. POPS WILL RANGE FROM LIKELY WEST AS THE FRONT MOVES
ACROSS...WITH CHANCE POPS ACROSS THE REMAINDER.

FRONT WILL BE SLOWING/STALLING ACROSS THE SOUTHEAST MONDAY NIGHT
THROUGH TUESDAY...PROLONGING THE CHANCE OF RAIN AREAWIDE...BUT
ESPECIALLY IN THE EAST...THROUGH THE DAY TUESDAY. MINS MONDAY NIGHT
WILL FALL INTO THE UPPER 30S NORTHEAST WITH UPPER 40S SOUTHEAST.
TEMPS TUESDAY WILL BE INFLUENCED BY INITIALLY WEAK COLD AIR
ADVECTION AS HIGH PRESSURE MOVES EAST INTO THE OHIO VALLEY AND
SHUNTS ANOTHER SURGE OF COLD AIR DOWN THE MIDATLANTIC SEABOARD FOR
THE MID TO LATE WEEK. THE COLD DRY AIR WILL SUPPRESS THE FRONTAL
ZONE SOUTH OF THE AREA AND DRY CONDITIONS SHOULD AT LAST PREVAIL
WEDNESDAY THROUGH FRIDAY. HIGHS EACH DAY WILL MAX OUT IN THE MID
40S...WHILE GOOD RADIATIONAL CONDITIONS WILL ALLOW MINS TO FALL INTO
THE MID 20S EACH NIGHT.
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.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
AS OF 1240 AM SATURDAY...

A STRONG COLD FRONT WILL DROP SOUTH-SOUTHEAST ACROSS THE AREA
BETWEEN 06 TO 15Z. IFR TO MVFR CEILINGS WITH RAIN WILL IMPACT TAFS
FROM NW TO SE. IN THE WAKE OF THE FRONT...LOW-LEVEL DRY COLD AIR
ADVECTION FROM THE WEST SHOULD ALLOW CEILINGS TO LIFT TO VFR ACROSS
THE WESTERN AND CENTRAL PIEDMONT DURING THE AFTERNOON...HOWEVER MVFR
CEILINGS SHOULD LINGER AT EASTERN TAF SITES(KRWI AND KFAY).

PRECIP IS FORECAST TO RE-DEVELOP FROM SOUTH TO NORTH ACROSS THE AREA
LATE THIS EVENING AND INTO THE OVERNIGHT HOURS AND WILL PERSIST
THROUGH MUCH OF THE DAY ON SUNDAY. THERE IS A GOOD CHANCE THAT KINT
AND KGSO WILL SEE A PERIOD OF FREEZING RAIN SUNDAY AS THE
TEMPERATURES FALL TO NEAR OR SLIGHTLY BELOW FREEZING. SOME LIGHT
FREEZING RAIN IS ALSO POSSIBLE AT KRDU SUNDAY MORNING BEFORE
CHANGING OVER TO A COLD RAIN. OTHERWISE... LIFR CIGS AND VSBYS ARE
EXPECTED SUNDAY INTO MONDAY.

SUB-VFR CONDITIONS ARE EXPECTED TO PREVAIL THROUGH TUESDAY WITH
PERIODS OF LIGHT RAIN AGAIN MONDAY INTO TUESDAY.

&&

.RAH WATCHES/WARNINGS/ADVISORIES...

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WINTER WEATHER ADVISORY FROM 4 AM TO 7 PM EST SUNDAY FOR NCZ008>010-
024-025-038>040. WINTER STORM WARNING FROM 4 AM SUNDAY TO MIDNIGHT
EST SUNDAY NIGHT FOR NCZ007-021>023.
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&&

$$

SYNOPSIS...CBL
NEAR TERM...CBL
SHORT TERM...CBL
LONG TERM...MLM
AVIATION...CBL