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000
FXUS62 KRAH 071726
AFDRAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
1226 PM EST FRI MAR 7 2014

.SYNOPSIS...
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A LOW PRESSURE SYSTEM WILL DEEPEN OFFSHORE THE CAROLINA COAST
TODAY AS AN UPPER LEVEL LOW TO THE SOUTH TRACKS EAST OF CAPE
HATTERAS. MOSTLY SUNNY SKIES AND ABOVE NORMAL TEMPERATURES ARE
EXPECTED OVER THE WEEKEND.
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&&

.NEAR TERM /THROUGH TONIGHT/...
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AS OF 1215 AM FRIDAY...

...WINTER STORM WARNING AND WINTER WEATHER ADVISORY EXTENDED UNTIL
400 PM EST THIS AFTERNOON...

OVERVIEW:
AN UPPER LEVEL WAVE CENTERED IN VICINITY OF CHARLESTON SC AT 16Z
WILL AMPLIFY AS IT TRACKS NORTHEAST OFFSHORE THE NORTH CAROLINA
COAST THIS AFTERNOON...ALONG WITH AN ATTENDANT SURFACE LOW
(CENTERED 70 MILES SOUTHEAST OF CAPE LOOKOUT AT 16Z).

PRECIPITATION:
PRECIP IS CURRENTLY EVOLVING INTO A HEAVY SW-NE BAND EXTENDING
FROM CHARLOTTE NORTHEAST TO ASHEBORO...ROXBORO...AND PETERSBURG
VA. THIS BAND IS ASSOCIATED WITH STRONG DIFFLUENCE ALOFT AND
STRONG MID-LEVEL FRONTOGENESIS ON THE NW PERIPHERY OF THE H85-H5
LOW. EXPECT THIS SW-NE ORIENTED BAND TO PROGRESS SLOWLY EAST
ACROSS CENTRAL NC THROUGH THE AFTERNOON...GRADUALLY PIVOTING TO A
MORE SSW-NNE OR S-N ORIENTATION IS IT SHIFTS INTO FAR EASTERN
PORTIONS OF THE STATE AFTER ~00Z. WITH THE ABOVE IN MIND... WILL
INDICATE A 100 PERCENT CHANCE OF PRECIP ACROSS THE ENTIRE AREA
THROUGH MID AFTERNOON...GRADUALLY ENDING FROM WEST-EAST LATE THIS
AFTERNOON AND EVENING WITH AN INCREASINGLY TIGHT REFLECTIVITY
GRADIENT ON THE BACKSIDE.

PRECIPITATION TYPE:
THERMAL PROFILES SUPPORT ALL RAIN ACROSS THE BULK OF CENTRAL NC
TODAY IN ASSOCIATION WITH A 1-3C LOW-LEVEL WARM NOSE MAINTAINED BY
~40 KNOT EAST/NORTHEAST LOW-LEVEL FLOW. IN THE PRESENCE OF A
STRONG DEFORMATION BAND ON THE WESTERN PERIPHERY OF AN H85-H5 LOW
CENTERED JUST SOUTH OF THE REGION AND TRACKING SLOWLY OFFSHORE TO
THE EAST...ONE WOULD TYPICALLY EXPECT INCREASING COLD ADVECTION
AND A POTENTIAL CHANGEOVER TO HEAVY SNOW. HOWEVER...THE PARENT
HIGH TO THE NORTH IS NO LONGER IN A FAVORABLE POSITION AND THE SFC
RIDGE AXIS EXTENDING INTO THE REGION IS WEAKENING...OBSERVATIONS
INDICATE THAT THE UPSTREAM AIRMASS TO THE NORTH...WHICH IS
LARGELY REMOVED FROM PRECIP/EVAP COOLING AND DYNAMIC COOLING
ALOFT...IS ALREADY MODIFYING WARMER AND RELATIVELY...AND STRONGER
EARLY MARCH INSOLATION ALL SUGGEST THAT A CHANGEOVER TO SNOW IS
VERY UNLIKELY IN MOST LOCATIONS. THE ONLY AREA WHERE A CHANGEOVER
FROM RAIN TO HEAVY WET SNOW MAY STILL BE POSSIBLE WILL BE IN
NORTHERN ALAMANCE...NORTHERN ORANGE...NORTHERN DURHAM...PERSON...
AND NORTHERN GRANVILLE COUNTIES WHERE TEMPS IN THE WARM NOSE ARE
PROGGED TO BE NO HIGHER THAN 1-2C IN THE PRESENCE OF HIGH
RATE/LONG DURATION PRECIPITATION (ASSOCIATED WITH THE SLOW MOVING
DEFORMATION BAND) WHERE STRONG MID-LEVEL ASCENT AND MELTING WITHIN
THE WARM NOSE COULD ALLOW A NEAR-FREEZING ISOTHERMAL LAYER TO
DEVELOP. DESPITE GROUND TEMPS ABOVE FREEZING THIS AFTERNOON...A
FEW OF THE AFOREMENTIONED AREAS COULD SEE SOME SNOW ACCUMULATION
IF A CHANGEOVER OCCURS AND RATES/DURATION ARE SUFFICIENT... THOUGH
THIS APPEARS INCREASINGLY UNLIKELY GIVEN CURRENT RADAR AND
OBSERVATIONAL TRENDS.

WINTER WARNING/ADVISORY: EXTENDED THE WARNING AND ADVISORY UNTIL
400 PM GIVEN THAT WINTRY PRECIPITATION IS EXPECTED THROUGH
EARLY/MID AFTERNOON AND THAT EXTREMELY HAZARDOUS CONDITIONS
PERSIST IN THE WARNING AREA WHERE SIGNIFICANT ICE ACCUMULATION
LAST NIGHT AND EARLY THIS MORNING HAS RESULTED IN WIDESPREAD
DOWNED TREES/POWER OUTAGES.

WIND ADVISORY:
WILL CANCEL THE WIND ADVISORY AS SOON AS POSSIBLE AND ALLOW THE
WINTER STORM WARNING/WINTER WEATHER ADVISORY TO COVER THE
POTENTIAL FOR DOWNED TREES/POWER LINES THAT MAY OCCUR WITH WIND
GUSTS OF 25-35 MPH THIS AFTERNOON. FOR SOUTHEAST PORTIONS OF THE
AREA WHERE PRECIP HAS BEEN AND WILL REMAIN ALL RAIN...NO
ADDITIONAL REPORTS OF DOWNED TREES OR POWER OUTAGES HAVE BEEN
RECEIVED SINCE WIND GUSTS EXCEEDED 40 MPH VERY EARLY THIS MORNING.

FLOODING:
AN AREAL FLOOD WARNING WILL REMAIN IN EFFECT UNTIL 600 PM FOR
AREAS WEST OF HIGHWAY 1 DUE TO ONGOING HEAVY RAINFALL (2"+
ALREADY) IN THE PRESENCE OF ALREADY SATURATED GROUND CONDITIONS...
ESPECIALLY IN URBAN AREAS. -VINCENT
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&&

.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/...
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

&&

.AVIATION /16Z FRIDAY THROUGH TUESDAY/...
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AS OF 655 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.

FREEZING RAIN MIXED WITH SLEET WILL CONTINUE AT KINT/KGSO THROUGH 14-
15Z BEFORE CHANGING OVER TO PREDOMINATELY RAIN.  RAIN MAY MIX WITH
SLEET AND SNOW LATE THIS MORNING...THOUGH CONFIDENCE IN THIS IS LOW
AT THE MOMENT.  ELSEWHERE TO THE EAST...RAIN AND DRIZZLE WILL
CONTINUE FOR MOST OF THE DAY...WITH PRECIP ENDING FROM WEST TO EAST
ACROSS THE AREA BETWEEN 21Z AND 06Z.  CEILINGS WILL REMAIN MOSTLY AT
IFR LEVELS...WITH IMPROVEMENT ONLY TO COME THIS EVENING AS OVERNIGHT
AS SOME DRIER AIR SPREAD ACROSS THE AREA BEHIND THE DEPARTING LOW
PRESSURE.  HOWEVER...NEAR SURFACE MISTURE IS NOT EXPECTED TO
CHANGE VERY MUCH...AND WITH SIGNIFICANT RAINFALL LAST EVENING
AND TODAY...THERE IS THE POTENTIAL FOR FOG TO DEVELOP LATE TONIGHT.

OUTLOOK...VFR CONDITIONS SHOULD PREVAIL SATURDAY INTO EARLY NEXT
WEEK.
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&&

.RAH WATCHES/WARNINGS/ADVISORIES...
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WIND ADVISORY UNTIL 6 PM EST THIS EVENING FOR NCZ007>011-
021>028-038>043-073>078-083>086-088-089.
WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
NCZ008>010-025-040-073-074.
WINTER STORM WARNING UNTIL 4 PM EST THIS AFTERNOON FOR NCZ007-
021>024-038-039.
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&&

$$

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