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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS62 KRAH 070734
AFDRAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
230 AM EST FRI MAR 7 2014

.SYNOPSIS...
-- Changed Discussion --
AN INTENSIFYING STORM SYSTEM WILL MOVE NORTHEASTWARD
ALONG THE SOUTHEAST COAST TODAY. THIS STORM SYSTEM WILL MOVE AWAY
FROM OUR AREA TONIGHT. HIGH PRESSURE WILL BUILD INTO THE REGION FOR
THE WEEKEND.
-- End Changed Discussion --

&&

.NEAR TERM /THROUGH FRIDAY NIGHT/...
AS OF 945 PM THURSDAY...

CHALLENGING FORECAST  OVERNIGHT INTO FRIDAY MORNING WITH SEVERAL
POSSIBLE SCENARIOS PLAUSIBLE. MAIN ADJUSTMENT WAS TO ADD WARREN
COUNTY TO THE ADVISORY BASED ON REPORTS OF SLEET COVERING THE GROUND
AND EXPECTATIONS OF THE THE LOW LEVEL COLD AIR REMAINING IN PLACE A
LITTLE LONGER THAN EARLIER THINKING.

LATEST SFC MESOANALYSIS INDICATES SFC PATTERN IN A CLASSIC CAD
SIGNATURE WITH THE RIDGE NOSES INTO THE NC PIEDMONT FROM A PARENT
HIGH CENTERED OVER BOSTON AT 01Z. PER LOW LEVEL STREAMLINE ANALYSIS
THIS FEATURE STILL SUPPLYING TEH WESTERN PIEDMONT WITH COOL DRY AIR.
MEANWHILE SFC LOW WAS OFF THE NE FL COAST LIFTING NE. THE TIGHT
PRESSURE GRADIENT BETWEEN THESE TWO WEATHER SYSTEM WAS CREATING
BLUSTERY NE ACROSS THE FORECAST AREA WITH GUSTS AROUND 30MPH IN THE
SANDHILLS AND SOUTHERN COASTAL PLAIN.

PRECIPITATION HAS OVERSPREAD THE FORECAST AREA WITH RAIN FALLING
ACROSS THE SOUTHERN COUNTIES INTO THE CENTRAL AND SOUTHERN COASTAL
PLAIN. A SWITCH TO A WINTRY MIX OCCURS IMMEDIATELY NORTH AND WEST OF
THIS REGION WITH PREDOMINATELY FREEZING RAIN/SLEET OCCURRING IN THE
NW PIEDMONT-TRIAD AND INTO THE FAR NORTHERN PIEDMONT NEAR THE VA
BORDER.

GSO 00Z SOUNDING DEPICTS A MODEST WARM NOSE AROUND 1 DEG C THOUGH
DOES SUGGEST AT A DEEP ISOTHERMAL LAYER BETWEEN 850-765MB. THIS
DEPICTION CLOSEST TO THE 12Z GFS WHILE 12Z NAM APPEARED TOO WARM
WITH THE WARM NOSE. DID NOTE THAT MHX 00Z SOUNDING HAD A WARM NOSE
AROUND 7 DEG C. WITH A STRONG LOW LEVEL ELY FLOW AROUND THE
APPROACHING SFC LOW...THIS POCKET OF WARM AIR WILL LIKELY TRANSLATE
EAST INTO AT LEAST THE COASTAL PLAIN...SANDHILLS AND PORTIONS OF THE
EASTERN PIEDMONT...KEEPING PRECIP ALL RAIN.

QUESTION ONE: HOW FAR WEST WILL THIS WARMER AIR REACH? BASED ON LOW
LEVEL STREAMLINES...THE WARMER AIR IN THE COASTAL PLAIN WILL MAKE IT
AS FAR WEST AS HIGHWAY ONE...AND POSSIBLY INTO THE WESTERN PIEDMONT.
THUS COULD SEE WARM NOSE ALOFT STRENGTHEN A BIT AFTER MIDNIGHT. 00Z
UPPER AIR ANALYSIS DID DEPICT DECENT MID-UPPER LEVEL CONFLUENCE IN
VICINITY OF THE PARENT HIGH WHICH SUGGEST THE HIGH SHOULD REMAIN
ANCHORED A BIT LONGER THAN ADVERTISED BY THE GFS (WHICH PUSHED THE
PARENT HIGH WILL OFFSHORE BY FRIDAY MORNING). THUS...CAD CONDITIONS
SHOULD PERSIST THROUGH THE OVERNIGHT INTO EARLY FRIDAY.

THUS FOR THE NEXT FEW HOURS...EXPECT A MIXTURE OF WINTRY PRECIP OVER
THE FAR NORTHERN PIEDMONT AND THE NW PIEDMONT WITH PRECIP RATES
DICTATING DOMINATE P-TYPE(HEAVIER RATES FAVOR SNOW AND SLEET,
LIGHTER AMOUNTS FREEZING RAIN).

AFTER 06Z...APPEARS THAT WESTERN PIEDMONT WILL COME UNDER THE
INFLUENCE OF MID LEVEL DEFORMATION ZONE AS MID LEVEL CYCLONE TAKES
SHAPE OVER CENTRAL SC. THIS SHOULD ENHANCE PRECIP RATES ACROSS THE
WESTERN PIEDMONT LATE TONIGHT INTO EARLY FRIDAY. DURING THIS
TIME...PARTIAL THICKNESSES REMAIN IN THE WINTRY MIX PORTION OF THE
NOMOGRAM WHILE THE RAP BUFKIT SOUNDINGS DEPICT A FAIRLY DEEP
ISOTHERMAL LAYER (FAVOR SNOW) WITH THE GFS AND NAM MAINTAINING  A
PROMINENT WARM NOSE (ESPECIALLY THE NAM AT 4 DEG C). WITH THE NEAR
SURFACE AIR MASS STILL DICTATED BY THE CHILLY PARENT HIGH AND AN
INCREASE IN PRECIP RATES AFTER MIDNIGHT...EXPECT A COMBINATION OF
SNOW AND FREEZING RAIN OVER THE WARNING AND ADVISORY AREA. SINCE
PRECIP WILL BE MIXED...THIS WILL CUT BACK ON ANY ONE P-TYPE
ACCUMULATING TO OUTRAGEOUS AMOUNTS. IF SNOW WERE TO
PREDOMINATE...COULD SEE AMOUNTS IN EXCESS OF 6 INCHES OCCUR.
CONVERSELY...IF IT WERE ALL FREEZING RAIN...ICE ACCRUAL A QUARTER TO
A HALF INCH PROBABLE. SINCE A MIX EXPECTED...EXPECT SNOW AMOUNTS TO
RANGE FROM A TRACE ALONG THE EASTERN FRINGE OF THE ADVISORY TO 2-3
INCHES WITH POCKETS OF 4 INCHES IN THE WARNING AREA. ICE ACCRUAL
APPROACHING A QUARTER OF AN INCH IN THE WARNING AREA...TRENDING TO A
TENTH OF AN INCH OR LESS IN THE ADVISORY. EVEN ON THE FRINGES
OUTSIDE OF ADVISORY (NORTHERN MOORE...LEE...WESTERN AND NORTHERN
WAKE AND WESTERN FRANKLIN)...A POCKET OR TWO OF LIGHT GLAZE POSSIBLE
BUT LIMITED EFFECTS SUGGEST KEEPING THIS AREA OUT FO TEH ADVISORY
FOR NOW.

WILL NEED TO MONITOR DEVELOPMENT OF DEFORMATION OVERNIGHT INTO
FRIDAY MORNING ALONG WITH MODEL/OBSERVED SOUNDING THERMAL
PROFILES...POTENTIAL FOR A QUICK BURST OF WET SNOW FRIDAY MORNING
OVER SECTIONS OF THE PIEDMONT...MAINLY WESTERN SECTIONS....AS MID-
UPPER LEVEL CYCLONE LIFTS NE OVER COASTAL CAROLINA.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
-- Changed Discussion --
AS OF 230 AM FRIDAY...

FOR SAT/SAT NIGHT: THE MID LEVEL TROUGH WILL BE TRACKING WELL OUT
OVER THE ATLANTIC BY DAYBREAK SAT... WITH FLAT MID LEVEL RIDGING AND
SURFACE HIGH PRESSURE BUILDING OVER THE SOUTHEAST STATES... AND A
DRY/STABLE COLUMN. WE MAY SEE SOME SHALLOW LOW STRATUS AT DAYBREAK
BUT PLENTIFUL SUNSHINE AND MIXING SHOULD SCOUR OUT ANY LOW CLOUDS BY
MID MORNING. SLIGHTLY ABOVE NORMAL THICKNESSES SUPPORT HIGHS FROM 63-
67. THE SPLIT FLOW PERSISTS OVER NOAM THROUGH SAT NIGHT WITH A
SHORTWAVE TROUGH CROSSING ONTARIO AND THE NRN GREAT LAKES... WHILE A
SOUTHERN STREAM TROUGH HANGS BACK OVER THE SOUTHERN PLAINS INTO NRN
MEXICO. THIS APPROACHING SHEAR AXIS WILL BE ACCOMPANIED BY A SURFACE
FRONT... AND THESE WILL RESULT IN INCREASING MID CLOUDS SAT NIGHT.
EXPECT PARTLY CLOUDY SKIES FOR MUCH OF THE NIGHT... WITH LOWS 40-45.

FOR SUN/SUN NIGHT: THE NORTHERN STREAM WAVE WILL MOVE QUICKLY ACROSS
THE NORTHEAST/CANADIAN MARITIMES ON SUNDAY WHILE THE SOUTHERN
PORTION CONTINUES TO HANG BACK ACROSS TX AND NW MEXICO. THE NAM IS
WEAKEST WITH THIS SOUTHERN TROUGH AND HAS TRENDED A BIT MORE
PROGRESSIVE THAN THE GFS/ECMWF. PREFER THE SLOWER/STRONGER GFS/ECMWF
SOLUTION BASED ON ITS CONSISTENCY AND AGREEMENT OF THE OP EC WITH
ITS ENSEMBLE MEAN. THE SURFACE FRONT IS EXPECTED TO PUSH SOUTHWARD
TOWARD THE NC/VA LINE (IN LINE WITH THE WEAKENING SHEAR AXIS ALOFT)
SUNDAY MORNING BUT THE QUICK PASSAGE OF THE NORTHERN STREAM WAVE OUT
OVER THE OPEN NW ATLANTIC SHOULD ALLOW A REBOUNDING OF MID LEVEL
HEIGHTS AND SURFACE PRESSURES DURING THE DAY... SUCH THAT WE SHOULD
SEE MINIMAL SENSIBLE WEATHER IMPACT FROM THIS GLANCING BLOW OF THE
BACKDOOR FRONT... ASIDE FROM A PERIOD OF BROKEN CLOUD COVER. LOW
LEVEL FLOW WILL REMAIN DOWNSLOPE OUT OF THE NW. THICKNESSES HOLD A
BIT ABOVE NORMAL... SUPPORTING HIGHS FROM 62 NORTH TO 69 SOUTH.
EXPECT MOSTLY CLEAR SKIES SUN NIGHT... ALTHOUGH THE POTENTIAL
BACKING OF SURFACE WINDS AROUND TO WSW (AS THE GFS INDICATES) MAY
BRING IN ENOUGH LOW LEVEL MOISTURE FOR SOME MORNING STRATUS/FOG.
LOWS 38-44. -GIH
-- End Changed Discussion --

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 315 PM THURSDAY...

EXPECT A BENIGN WEATHER PATTERN AND ABOVE NORMAL TEMPERATURES TO
PERSIST EARLY NEXT WEEK GIVEN UNIDIRECTIONAL FLOW ALOFT AND A LIGHT
SOUTHWEST FLOW IN THE LOWER LEVELS. CHANCES FOR RAIN WILL INCREASE
BY MID NEXT WEEK (WED/THU) IN ASSOCIATION WITH AN INCREASINGLY
AMPLIFIED UPPER LEVEL PATTERN OVER THE EAST CONUS. -VINCENT

&&

.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AS OF 1245 AM FRIDAY...

A STRONG LOW PRESSURE SYSTEM MOVING NORTHEAST ALONG THE COAST IN
CONJUNCTION WITH AN AREA OF HIGH PRESSURE NOISING SOUTHWARD INTO THE
PIEDMONT WILL CREATE WINDY CONDITIONS THROUGH THE MORNING HOURS
ACROSS CENTRAL NC. THE STRONGEST WIND GUSTS (FROM THE NORTHEAST)
WILL BE ALONG THE COASTAL PLAIN...SANDHILLS AND EASTERN PIEDMONT
WHERE GUSTS UP TO 35KTS WILL OCCUR.

THIS SAME WEATHER SYSTEM WILL SPREAD PLENTY OF PRECIPITATION INTO
CENTRAL NC OVERNIGHT INTO THIS MORNING...WITH PRECIPITATION
GRADUALLY DIMINISHING THIS AFTERNOON. RAIN WILL OCCUR AT KFAY AND
KRWI WHILE A MIX OF RAIN AND SLEET WILL OCCUR AT KRDU WITH A BRIEF
PERIOD OF FREEZING RAIN POSSIBLE TOWARD DAYBREAK. OVER THE WESTERN
PIEDMONT INCLUDING THE TRIAD TERMINALS...A WINTRY MIX OF FREEZING
RAIN...SLEET AND SNOW CAN BE EXPECTED. PRECIP INTENSITIES WILL DRIVE
PRECIPITATION TYPE. DURING HEAVIER PRECIP RATES EXPECT SLEET AND
SNOW. DURING LIGHTER RATES...FREEZING RAIN WILL DOMINATE. THIS WILL
LEAD TO A DECENT ICE COATING ON EXPOSED OBJECTS WITH SNOW/SLEET
ACCUMULATION AS HIGH AS 3-4 INCHES POSSIBLE.

THIS WEATHER SYSTEM WILL CAUSE WIDESPREAD IFR/LIFR CEILINGS THROUGH
THE MORNING HOURS...WITH CEILINGS GRADUALLY LIFTING TO MVFR CRITERIA
THIS AFTERNOON.

LATER THIS AFTERNOON AND INTO TONIGHT...THE LOW PRESSURE SYSTEM WILL
EXIT OUR REGION. N-NW WINDS WILL USHER IN DRIER AIR...LEADING TO
CLEARING SKIES. VFR CONDITIONS SHOULD PREVAIL LATE TONIGHT AND PERSIST
INTO EARLY NEXT WEEK.

&&

.RAH WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
WINTER STORM WARNING UNTIL NOON EST TODAY FOR NCZ007-021>023-
038.
WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR NCZ008>010-
024-025-039-040-073-074.
-- End Changed Discussion --

&&

$$

SYNOPSIS...WSS
NEAR TERM...WSS
SHORT TERM...HARTFIELD
LONG TERM...VINCENT
AVIATION...WSS