-- Discussion containing changed information from previous version are highlighted. --
000
FXUS62 KRAH 070842
AFDRAH

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

.SYNOPSIS...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.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 340 AM FRIDAY...

WINTER STORM WARNINGS AND ADVISORIES WILL CONTINUE THIS MORNING.  A
WIND ADVISORY WILL BE IN EFFECT UNTIL 6PM.

THE CORE OF A STRONG UPPER LOW IS CURRENTLY OVER THE FLORIDA
PANHANDLE...WITH ITS ASSOCIATED 1005MB SURFACE LOW DUE EAST OF
CHARLESTON PER LATEST REGIONAL SATELLITE AND SURFACE OBS.  THE UPPER
LOW WILL BEGIN TO LIFT TO THE EAST-NORTHEAST THIS MORNING WHILE THE
SURFACE LOW TRACKS SLOWLY ALONG THE NC COAST....PASSING TO THE EAST
OF HATTERAS BY 00Z THIS EVENING.  THE LARGE PRECIP SHIELD
ENCOMPASSING NEARLY ALL OF NC IS BEGINNING TO ERODE A BIT ON THE
SOUTHERN EDGE AS THE DRY SLOT PUSHES NORTH.  A STRONG
FRONTOGENETICALLY DRIVEN BAND OF PRECIP HAS PUSHED NORTH
OF I-40....AND WITHIN THIS BAND PRECIP HAS TRANSITIONED FROM
FREEZING RAIN TO PERIODS OF MODERATE TO HEAVY SNOW AND
SLEET...MAINLY FROM PERSON COUNTY DOWN TO THE TRIAD.  A FEW REPORTS
HAVE COME IN OVER THE PAST HOUR OR TWO...RANGING FROM 0.5"
TO NEAR 2.5" IN PERSON COUNTY.  ICE AMOUNTS ARE HARDER TO COME
BY...BUT AN ICE SENSOR AT KINT REPORTS TWO TENTHS OF AN INCH.  POWER
OUTAGES ARE INCREASING VERY QUICKLY...ESPECIALLY ACROSS THE
TRIAD...NO DOUBT AIDED BY THE REGULAR WIND GUSTS OF 25-30MPH.

WHILE THE PRIMARY PRECIP BAND IS PUSHING NORTH TOWARD THE VA
BORDER...THE SPC MESOANALYSIS STILL SHOWS STRONG 850-700MB FGEN
DRAPED WEST-EAST ACROSS AREA...WITH STRONG MOISTURE TRANSPORT
INTO THE REGION.  THE APPROACHING DRY SLOT WILL TEND TO CUT DOWN ON
QPF WITH TIME...BUT EXPECT THAT PERIOD OF HEAVIER PRECIP WILL
CONTINUE FOR A FEW MORE HOURS.  MEANWHILE...IR IMAGERY
INDICATES CLOUD TOPS ARE COOLING RAPIDLY OVER WESTERN NC/SC
WHICH SUGGESTS THE DEFORMATION BAND IS BEGINNING TO TAKE SHAPE.
MODELS BRING THE DEFORMATION BAND WITH AND ADDITIONAL HALF INCH OF
QPF DURING THE DAY.

THE SURFACE WETBULB FREEZING LINE CURRENTLY STRETCHES FROM LEXINGTON-
ASHEBORO-CHAPEL HILL-HENDERSON...AND IS BEGINNING REINFORCED BY A SURGE
OF NORTHEASTERLY WINDS AND DRIER AIR OVER THE PIEDMONT OF VIRGINIA.
NORTH OF THIS LINE...FREEZING RAIN WILL CONTINUE TO BE THE PRIMARY
PTYPE...WITH PERIODS OF SLEET AND SNOW WITH HEAVIER PRECIP BANDS.
THE WETBULB TEMPS SHOULD BEGIN TO CREEP UP AFTER SUNRISE WITH A
LITTLE WARMING...BUT MAY LINGER ACROSS THE NORTHERN PORTIONS OF THE
PIEDMONT FOR A COUPLE ADDITIONAL HOURS.  BEYOND 15Z...THERE IS SOME
CONCERN THAT SOME DYNAMIC COOLING AND HIGHER PRECIP RATES WITH THE
DEFORMATION BAND MAY ERODE THE 1-2C WARM NOSE (06Z KGSO RAOB) AN
ALLOW SOME ADDITIONAL SNOW/SLEET THROUGH MIDDAY.  WITH SURFACE TEMPS
OF 32-34...ADDITIONAL ACCUMULATION WOULD BE LIMITED. CONFIDENCE
IN THIS IS LOW...BUT IT WOULD BE MOST LIKELY WITHIN THE WARNING
COUNTIES AND WOULD NOT REQUIRE UPGRADING.

THE OTHER CONCERN WE HAVE ARE THE STEADY 30-35KT GUSTS IN THE
EAST.  WHEN COMBINED WITH THE AMOUNT OF RAIN THAT HAS FALLEN/WILL
FALL TODAY AND WET SOIL...WE ARE CONCERNED ABOUT ADDITIONAL DOWNED
TREES.  THERE ARE OF COURSE THOUSANDS OF POWER OUTAGES IN THE WEST
DUE TO WIND AND  ICING...SO THE EASIEST COURSE OF ACTION IS TO ISSUE
A WIND ADVISORY FOR THE ENTIRE CWA.  THIS WILL BE IN EFFECT UNTIL
6PM TODAY.

TONIGHT...PRECIP PULLS OUT FROM WEST TO EAST AND SHOULD CLEAR THE
COASTAL PLAIN BY MIDNIGHT.  HIGH PRESSURE BEGINS TO NOSE IN FROM THE
SOUTHWEST WITH CLEARING SKIES.  GUIDANCE SUGGESTS LOWS WILL DIP TO
AROUND THE FREEZING MARK IN THE WEST...SO BLACK ICE IS AT LEAST
WORTH NOTING AND CAN BE ADDRESSED LATER.  LOWS 30-34.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
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

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
-- Changed Discussion --
AS OF 335 AM FRIDAY...

FOR MON/TUE: GENERALLY QUIET WITH A FLAT WNW MID LEVEL FLOW AND A W-
E ORIENTED SURFACE HIGH PRESSURE AREA SITUATED OVER THE GULF COAST
AND SOUTHEAST STATES. THE MID LEVEL LOW OVER NRN MEXICO IS EXPECTED
TO OPEN UP AND TRACK EASTWARD TO THE NW GULF MON NIGHT/TUE
(PROPELLED BY A DIGGING TROUGH... WHICH SHOULD RAISE HEIGHTS OVER
THE CAROLINAS... INSTIGATING A STRENGTHENING SW SURFACE FLOW AND
DRAWING IN WARMER AIR. EXPECT A FEW MID/HIGH CLOUDS WITH A PASSING
DISTURBANCE JUST TO OUR NNE... BUT OTHERWISE WE SHOULD SEE PLENTY OF
CLEAR/MOSTLY SUNNY SKIES. GFS/ECMWF SUGGEST THICKNESSES AROUND 20 M
ABOVE NORMAL MON MORNING AND AROUND 30 M ABOVE NORMAL TUE MORNING.
WILL FINALLY SEE SOME SPRINGLIKE WEATHER... WITH HIGHS OF 65-70 MON
AND 70-75 TUE. LOWS IN THE UPPER 30S TO MID 40S.

FOR WED/THU: THE NW GULF WAVE SHOULD CONTINUE TO KICK TO THE ENE
WHILE DAMPENING OUT... AS DEEPENING MID LEVEL TROUGHING OVER THE
FRONT RANGE AND PLAINS SHIFTS EASTWARD. THE ECMWF REMAINS MUCH
DEEPER THAN THE GFS WITH THIS... DIGGING THIS TROUGH WELL INTO THE
SRN PLAINS AS IT APPROACHES OUR AREA FROM THE WEST AND PHASES WITH
THE NRN STREAM TROUGH OVER THE ERN SEABOARD BY THU. THE GFS HANGS
THIS TROUGH BACK OVER THE FOUR CORNERS BUT ALLOWS AMPLIFICATION OF
THE NRN STREAM OVER THE NORTHEAST/MIDATLANTIC STATES DURING THIS
TIME. BOTH SOLUTIONS BRING A SURFACE LOW WITH ATTENDANT FRONT INTO
AND THROUGH NC LATE WED INTO THU... BRINGING INCREASING RAIN CHANCES
STARTING WED AND EXTENDING INTO THU... WITH COLDER POST-FRONTAL AIR
MOVING IN ON THU. WILL GO WITH A COMPROMISE SOLUTION FOR THE
SENSIBLE WEATHER (AS THE DETAILS ARE TOUGH TO RESOLVE AT THIS TIME)
BUT LEAN TOWARD THE ECMWF TIMING... WITH SMALL RAIN CHANCES ARRIVING
LATE TUE NIGHT STRETCHING THROUGH WED/WED NIGHT... EXITING EARLY
THU. EXPECT INCREASED CLOUDS WED... A BIT COOLER BUT CONTINUED
FAIRLY MILD... WITH MID-UPPER 60S FOR HIGHS. THICKNESSES SUPPORT
HIGHS FALLING BACK INTO THE 50S FOR THU. -GIH
-- End Changed Discussion --

&&

.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...
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.

&&

$$

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