Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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243 FXUS62 KRAH 121156 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 655 AM EST FRI FEB 12 2016 .SYNOPSIS... AN UPPER LEVEL DISTURBANCE WILL TRACK ACROSS THE CAROLINAS TODAY. IN THE WAKE OF THE DISTURBANCE...ARCTIC HIGH PRESSURE WILL BUILD INTO THE REGION FROM THE NORTHWEST OVER THE WEEKEND. && .NEAR TERM /TODAY/... AS OF 350 AM FRIDAY... JUST MINOR ADJUSTMENTS REQUIRED TO THE NEAR TERM FORECAST. STILL FAIRLY CERTAIN THAT WINTRY PRECIPITATION WILL AFFECT SECTIONS OF THE COASTAL PLAIN LATER TODAY. FORECAST NOW UNCERTAIN AS TO THE AMOUNT AND/OR EXTENT OF WINTRY PRECIPITATION OVER THE TRIANGLE AND THE SANDHILLS. FORECAST SCENARIO HAS CHANGED LITTLE. A RATHER POTENT S/W DEPICTED ON WATER VAPOR IMAGERY EXITING THE MID MS VALLEY WILL CONTINUE TO MOVE EAST-SE. AS IT GETS CLOSER TO OUR REGION...THIS FEATURE WILL INDUCE AN AREA OF LOW PRESSURE TO FORM OFF THE SC COAST WHICH WILL MOVE EAST-NE...PARALLELING THE SOUTHERN COAST OF NC THIS AFTERNOON- EARLY EVENING. IN ADDITION...THE APPROACHING S/W WILL INDUCE A SLY FLOW TO DEVELOP JUST ABOVE THE SURFACE. THIS WILL INITIATE A LOW LEVEL WAA SCHEME...MAINLY OVER THE SE THIRD OF OUR CWA...LATER THIS MORNING AND THIS AFTERNOON. MODEL RH CROSS SECTIONS DEPICT DEEPEST MOISTURE OVER THE EASTERN THIRD OF THE FORECAST AREA WHILE MOISTURE OVER THE WESTERN HALF IS NOT AS DEEP/EXTENSIVE. IN ADDITION...BETTER LIFT WILL BE CONCENTRATED MORE OVER THE SANDHILLS AND COASTAL PLAIN DUE TO THE LOW LEVEL ISENTROPIC UPGLIDE AND LIFT SUPPLIED BY THE NOSE OF A 130+KT JET. MAIN DIFFERENCE NOTED IN THE MODELS IS THE STRENGTH OF THE PROJECTED WARM NOSE JUST ABOVE THE SURFACE. 00Z NAM DEPICTS A FAIRLY STRONG WARM NOSE (3-4 DEGREES C) DEVELOPING OVER THE SANDHILLS AND SOUTHERN COASTAL PLAIN BY LATE MORNING. IN CONTRAST...THE GFS HAS A WARM NOSE OF 1-1.5 DEGREES C. IF THE NAM VERIFIES...WOULD SEE MORE LIQUID RATHER THAN WINTRY MIX AND A BETTER CHANCE FOR A 2-3 HOUR PERIOD OF FREEZING RAIN IN THE SANDHILLS/SOUTHERN COASTAL PLAIN AND MORE OF A SNOW/SLEET MIXTURE FARTHER NORTH...LEADING TO LESS SNOW ACCUMULATION. IF GFS VERIFIES...PREDOMINATE P-TYPE ACROSS THE NORTHERN COASTAL PLAIN WILL BE SNOW...WITH A MIXTURE OF SLEET/SNOW/RAIN OVER THE SANDHILLS/COASTAL PLAIN. OVERALL PRECIPITATION AMOUNTS WITH THIS EVENT WILL BE LIGHT...LIKELY TOTALING NO MORE THAN A FEW HUNDREDTHS ACROSS MOST OF THE PIEDMONT...INCREASING TO ABOUT A TENTH OF AN INCH IN THE CENTRAL- NORTHERN COASTAL PLAIN. THUS...EXPECT A DRY MORNING COMMUTE FOR ABOUT ALL OF CENTRAL NC WITH PRECIP EXPANDING IN COVERAGE AND INTENSITY OVER THE EASTERN THIRD BETWEEN 10 AM AND 1 PM. BULK OF STEADIER PRECIPITATION SHOULD OCCUR BETWEEN 11 AM AND 3 PM...WITH PRECIP QUICKLY DIMINISHING WEST-EAST BETWEEN 3 AND 6 PM. FAIRLY CERTAIN THAT A LIGHT ACCUMULATION OF SNOW/SLEET WILL OCCUR OVER THE NORTHERN HALF OF THE COASTAL PLAIN. OVER THE SOUTHERN HALF OF THE COASTAL PLAIN AND SANDHILLS...EXPECT TO SEE NO MORE THAN A DUSTING OF SNOW AND SLEET AND MAYBE (AND THIS MAY BE A STRETCH)A LITTLE GLAZE HERE AND THERE. OVER THE TRIANGLE...WHILE CERTAIN THAT LIGHT WINTRY MIX WILL OCCUR...AMOUNTS MAY END UP BEING NO MORE THAN A DUSTING IF EVEN THAT. ACROSS THE REMAINDER OF THE PIEDMONT INCLUDING THE TRIAD...PATCHES OF LIGHT SNOW OR SNOW FLURRIES...MIXED AT TIMES WITH RAIN OR SLEET...EXPECTED THOUGH AMOUNTS WILL AVERAGE A TRACE TO A HUNDREDTH OR TWO. WHILE FEEL LESS CONFIDENT THAT ADVISORY CONDITIONS WILL OCCUR ALONG THE WESTERN PERIPHERY OF THE CURRENT ADVISORY AREA (ESSENTIALLY THE HIGHWAY 1 CORRIDOR)...HATE TO TAKE IT DOWN BEFORE THE SITUATION HAS UNFOLDED. THUS WILL LEAVE CURRENT ADVISORY INTACT. FEEL THAT ANY IMPACTS WILL BE LIMITED TO SCATTERED SLICK SPOTS...AND CONFINED MOSTLY TO THE NORTHERN COASTAL PLAIN. EXPECT THESE SLICK SPOTS TO BE A CONCERN/NUISANCE FOR TRAVEL IN THE NORTHERN COASTAL PLAIN THIS AFTERNOON AND INTO TONIGHT. PRECIPITATION FALLING THROUGH THE DRY SUB CLOUD LAYER WILL LEAD TO EVAPORATIVE COOLING. THIS WILL LIMIT THE NORMAL DIURNAL TEMPERATURE RECOVERY. MAX TEMPS TODAY SHOULD VARY FROM NEAR FREEZING OVER THE NORTHERN COASTAL PLAIN TO THE MID 30S WEST AND SOUTH. && .SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/... AS OF 350 AM FRIDAY... ATTENDANT SFC FRONT WITH THE POTENT S/W WILL CROSS OUR REGION LATE TONIGHT/EARLY SATURDAY. NLY WINDS BEHIND THIS FEATURE WILL ADVECT A MUCH COLDER AIR MASS INTO CENTRAL NC...SETTING THE STAGE FOR BITTERLY COLD CONDITIONS. HIGH TEMPS SATURDAY WILL STRUGGLE TO REACH FREEZING ACROSS THE NORTHERN THIRD AND ONLY WARM TO THE MID- UPEPR 30S SOUTH. A STOUT NLY WIND WILL CREATE WIND CHILL VALUES IN THE TEENS ACROSS THE NORTH AND THE 20S OVER THE SOUTH. BRUTALLY COLD CONDITIONS SATURDAY NIGHT AS THE ARCTIC AIR MASS CONTINUES TO OVERSPREAD THE REGION. OVERNIGHT TEMPS WILL FALL TO BETWEEN 10 AND 15 ABOVE ACROSS THE NORTH...AND INTO THE MID TEENS OVER THE SOUTH. WITH THE WIND FACTORED IN...IT WILL FEEL MORE LIKE 0 TO 5 ABOVE. && .LONG TERM /SUNDAY THROUGH THURSDAY/... AS OF 350 AM FRIDAY... SUNDAY THROUGH TUESDAY: ARCTIC HIGH PRESSURE WILL SETTLE OVER THE AREA ON SUNDAY (WITH HIGHS GENERALLY IN THE 30S)... BEFORE QUICKLY SHIFTING OFFSHORE SUNDAY NIGHT INTO MONDAY. MEANWHILE... S/W ENERGY ALOFT WILL IS FORECAST TO DIG SOUTHEASTWARD FROM THE CENTRAL/SOUTHERN PLAINS SUNDAY NIGHT INTO MONDAY AND AMPLIFY ACROSS THE DEEP SOUTH... WITH A DEVELOPING SURFACE LOW. WAA IN ADVANCE OF THIS SYSTEM WILL ALLOW FOR SOME LIGHT PRECIP TO DEVELOP ON MONDAY MORNING... WITH THE BEST CHANCES ACROSS THE NORTHWESTERN PIEDMONT. GIVEN THE DRY COLD AIRMASS DEPOSITED BY THE DEPARTING ARCTIC SURFACE HIGH WE WILL LIKELY SEE THE PRECIP START OFF AS SNOW/WINTRY MIX WITH AN IN-SITU CAD DEVELOPING. HOWEVER... THIS FIRST BAND OF PRECIP IS EXPECTED TO BE LIGHT. MEDIUM RANGE MODEL GUIDANCE HAS TRENDED FURTHER INLAND WITH THE TRACK OF THE PRIMARY SURFACE LOW... TRACKING IT GENERALLY FROM SW TO NE ACROSS CENTRAL NC TUESDAY MORNING/AFTERNOON... ALONG WITH TROUGH ALOFT BECOMING NEGATIVELY TILTED AS IT CROSS THE REGION. IF THESE TRENDS CONTINUE... THERE WOULD BE A POTENTIAL FOR A LIGHT WINTRY MIX (THOUGH SOME LOCATIONS ACROSS THE EAST AND SOUTH MAY WARM TOO MUCH BEFORE PRECIP ARRIVES) MONDAY MORNING... WITH PRECIP CHANGING TO FREEZING RAIN THEN RAIN THROUGH THE DAY ON MONDAY IN A SOUTHEAST TO NORTHWEST FASHION. GIVEN THE RUN TO RUN MODEL DIFFERENCES.... HAVE ELECTED TO STAY CLOSER TO THE LATEST GFS VS THE ECMWF WITH REGARD TO THICKNESS AMD RAW TEMPS... AS THE GFS IS MORE CONSISTENT WITH ITS PAST RUNS. THE LATEST ECMWF IS WARMER AND TURN THE PRECIP TO ALL RAIN EVEN QUICKER. THE MAIN BULK OF THE PRECIP IS EXPECTED TO ARRIVE ON MONDAY NIGHT INTO TUESDAY MORNING... WITH POSSIBLY 1 TO 2 INCHES OF RAIN. WILL NOT INCLUDE ANY THUNDER IN THE FORECAST NOW... GIVEN WE ARE STILL TALKING ABOUT A SYSTEM THAT IS STILL OUT IN THE PACIFIC... BUT WITH THE CURRENT ADVERTISED NEG. MID LEVEL TROUGH (BOTH ON THE ECMWF AND GFS) WE COULD SEE SOME EMBEDDED STORMS. HIGH AND LOW TEMPS WILL BE TRICKY DURING THIS PERIOD AND BE DRIVEN BY THE INCREASING MOISTURE AND PRECIP... ALONG WITH THE TRACK OF THE SURFACE LOW. FOR NOW WILL SHOW TEMPS STARTING OUT IN THE 20S MONDAY MORNING... THEN RISING THROUGH MONDAY TUESDAY MORNING/AFTERNOON... BEFORE FALLING AGAIN MID TO LATE TUESDAY AFTERNOON IN THE WAKE OF THE SURFACE LOW. FOR NOW THIS YIELDS HIGH TEMPS IN THE LOWER TO MID 30S NW TO THE MID TO UPPER 40S SE ON MONDAY... WITH LOWS DURING THE MONDAY NIGHT PERIOD VERY SIMILAR TO HIGHS ON MONDAY (LIKELY OCCURRING DURING MONDAY EVENING). TEMPS TUESDAY WILL DEPEND GREATLY ON THE TRACK OF THE LOW... WITH THE POTENTIAL FOR TEMPS TO CLIMB INTO THE 60S ACROSS SOUTHERN AND EASTERN PORTIONS OF THE AREA (THOUGH WILL NOT GO ANYWHERE CLOSE TO THAT HIGH YET). TUESDAY NIGHT THROUGH THURSDAY: MODELS HAVE TREND TOWARDS A L/W TROUGH REMAINING OVER THE AREA THROUGH WEDNESDAY NIGHT... WITH PERHAPS A MOISTURE STARVED DISTURBANCE MOVING ACROSS THE AREA ON WEDNESDAY OR THURSDAY. THUS... HAVE LOWERED TEMPS A BIT... HIGHS GENERALLY IN THE 50S THOUGH... WITH LOWS IN THE 30S (NEAR TO SLIGHTLY BELOW NORMAL). && .AVIATION /12Z FRIDAY THROUGH TUESDAY/...
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AS OF 655 AM FRIDAY... AVIATION CONDITIONS WILL BEGIN TO DETERIORATE AFTER 14Z WITH MVFR CEILINGS HIGHLY PROBABLE IN VICINITY OF KFAY AND KRWI LATER THIS MORNING AS AREAS OF WINTRY PRECIPITATION DEVELOP ACROSS THE EASTERN HALF OF CENTRAL NC. PRECIP WILL START OUT AS A SNOW OR SNOW/SLEET MIXTURE...THEN TRANSITION WITHIN AN HOUR OR TWO TO SNOW/FREEZING RAIN IN VICINITY OF KFAY ...FINALLY TRANSITIONING TO MOSTLY A COLD RAIN BY EARLY AFTERNOON. POCKETS OF LIGHT SNOW OR SNOW FLURRIES WILL OCCUR ACROSS THE PIEDMONT WHILE LIGHT SNOW WILL OCCUR IN VICINITY OF KRWI. AVIATION CONDITIONS WILL IMPROVE WEST-EAST LATE THIS AFTERNOON THROUGH THIS EVENING WITH CEILINGS LIFTING/DISSIPATING. A COLD FRONT WILL CROSS THE AREA LATE TONIGHT...VEERING THE WINDS TO A NW DIRECTION. THESE NORTHERLY WINDS WILL BE BLUSTERY ON SATURDAY AS GUSTS WILL FREQUENTLY REACH 22-25KTS. VFR CONDITIONS EXPECTED SATURDAY THROUGH SUNDAY. CHANCES FOR ADVERSE AVIATION CONDITIONS WILL INCREASE MONDAY THROUGH TUESDAY AS AN AREA OF LOW PRESSURE AND ASSOCIATED SUB VFR CEILINGS AND VISIBILITY DUE TO PRECIPITATION AFFECT THE REGION.
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&& .CLIMATE... HERE ARE THE RECORD LOWS AND RECORD LOW MAXIMUM TEMPERATURES FOR SAT FEB 13TH AND SUN FEB 14TH AT GSO... RDU... AND FAY: REC YR REC YR LOW LOW MAX ---------------------------------------------- GSO: 02/13 11 1955 31 1986 02/14 6 1905 22 1914 RDU: 02/13 4 1899 10 1899 02/14 -2 1899 27 1916 FAY: 02/13 14 1973 32 1955 02/14 12 1968 33 1916 && .RAH WATCHES/WARNINGS/ADVISORIES...
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WINTER WEATHER ADVISORY THROUGH 7 PM EST TODAY FOR NCZ010-011-026>028-041>043-077-078-085-086-088-089.
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&& $$ SYNOPSIS...VINCENT NEAR TERM...WSS SHORT TERM...WSS LONG TERM...BSD AVIATION...WSS

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