Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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606 FXUS62 KRAH 071802 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 100 PM EST SUN FEB 7 2016 .SYNOPSIS... A STRONG COASTAL LOW WILL DEVELOP OFF THE SOUTH CAROLINA COAST TODAY AND MOVE AWAY TONIGHT AND MONDAY. AN UPPER LEVEL DISTURBANCE AND COLD FRONT WILL APPROACH THE REGION LATE MONDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1015 AM SUNDAY... ...SHORT FUSE WINTER WEATHER ADVISORY FOR JOHNSTON...WAYNE...WILSON...HARNETT...CUMBERLAND...SAMPSON COUNTIES THIS MORNING WITH NUMEROUS TRAFFIC ACCIDENTS REPORTED FROM BURSTS OF HEAVIER SLEET... MSAS SHOWS A ~1003MB SURFACE LOW EAST OF CHARLESTON SC THIS MORNING...IN RESPONSE TO A 553DM UPPER LOW PIVOTING OVER THE SAVANNAH RIVER BASIN. THE PRECIP SHIELD NORTHWEST OF THE LOW EXTENDS THROUGH THE NC COASTAL PLAIN....WHERE TEMP PROFILES ARE MARGINAL FOR A WINTRY MIX OF PTYPES...A SLIGHT WARM NOSE OF 1-2C AT 5K FT AND SURFACE TEMPS IN THE 33-35F RANGE. HOWEVER...IN THE PAST HOUR OR SO THE RATES HAVE BEEN HIGH ENOUGH FOR MELTING AND WETBULBING TO PRODUCE PERIODS OF PREDOMINATELY SLEET IN WILSON....WAYNE...JOHNSTON...AND NORTHERN SAMPSON COUNTIES. A WINTER WEATHER ADVISORY HAS BEEN ISSUED FOR THESE COUNTIES GIVEN NUMEROUS TRAFFIC ACCIDENTS. DUAL POL CC SUGGESTS LIGHT TO MODERATE SLEET WILL BE POSSIBLE AS FAR WEST AS RALEIGH AND SANFORD AS WELL. RAP AND HRRR SOUNDINGS SHOW THE SMALL WARM NOSE CONTINUING TO COOL THROUGH EARLY AFTERNOON...SO ITS ENTIRELY POSSIBLY THAT PERIODS OF MODERATE SLEET MAY PRODUCE A HALF INCH OF SO SLEET....WITH ANOTHER QUARTER INCH OF QPF STILL POSSIBLE AS THE PRECIP BAND PIVOTS OVER THE AREA. A DOWNWARD TEND IN PRECIP...ALBEIT LIKELY VERY SLOW...IS EXPECTED THIS AFTERNOON AS THE LOW DEEPENS EAST OF CAPE FEAR AND THEN FINALLY BEGINS TO MOVE EAST AND FURTHER OFFSHORE. && .SHORT TERM /MONDAY THROUGH MONDAY NIGHT/... AS OF 321 AM SUNDAY... REGARDLESS OF HOW CLOSE TO THE COAST A COASTAL LOW WOBBLES AS IT BOMBS OFF THE SOUTHEAST US COAST DURING THE NEXT 24-36 HOURS...THE RESULTANT DEEP CYCLONE IS FORECAST TO ACCELERATE NORTHEASTWARD AND AWAY FROM THE NC COAST TONIGHT...IN RESPONSE TO A "KICKER" VORTEX AND ACCOMPANYING ELONGATED SHORTWAVE TROUGHS IN SHORT WAVELENGTH FLOW ALOFT...FORECAST TO PIVOT FROM THE UPPER MIDWEST TO THE TN AND LOWER MS VALLEYS THROUGH EARLY MON. CLEARING SKIES ARE EXPECTED TONIGHT WITH LOWS IN THE UPPER 20S TO LOWER 30S. AN AREA OF BROAD BUT STRONG 100-150 METER HEIGHT FALLS AND COOLING/FGEN ALOFT...AND ASSOCIATED FORCING FOR ASCENT AND POCKET OF STEEP (7.5 C/KM) 850-500 MB LAPSE RATES...WILL SUPPORT THE EASTWARD MAINTENANCE OF A BAND OF SHOWERS INTO CENTRAL NC DURING THE AFTERNOON AND EVENING. A "WARMING" DEEP LAYER SOUTHWEST FLOW...INCLUDING A SSW SURFACE BREEZE AND TEMPERATURES MONDAY AFTERNOON IN THE 40S TO MIDDLE 50S...WILL ENSURE THIS ACTIVITY WILL FALL AS RAIN. MONDAY NIGHT: STRONG CAA IN THE WAKE OF THE ARCTIC FRONTAL PASSAGE ASSOCIATED WITH THE MILLER-B SECONDARY CYCLOGENESIS MOVING OFF THE NC/VA COAST MONDAY EVENING....MAY SUPPORT A BRIEF TRANSITION/CHANGE-OVER TO A FEW WET SNOWFLAKES BEFORE PRECIP ENDS ACROSS THE AREA. NO ACCUMULATIONS/IMPACTS ARE EXPECTED WITH LOWS TUESDAY MORNING IN THE MID 20S NORTHWEST PIEDMONT TO LOWER 30S EAST. && .LONG TERM /TUESDAY THROUGH SATURDAY/... AS OF 335 1M SUNDAY... MOISTURE WILL BE SCARCE...BUT PERIODS OF STRONG DCVA IN ASSOCIATION WITH STOUT VORT LOBES ROTATING THROUGH THE BASE OF THE ANOMALOUS DEEP UPPER TROUGH IN PLACE(H5 ANOMALIES 2 TO 4 SD BELOW NORMAL)ACROSS THE EASTERN US WILL SUPPORT THE POTENTIAL FOR FLURRIES ON TUESDAY ACROSS THE NORTHERN HALF OF THE FORECAST AREA ON TUESDAY. THE BIG WEATHER STORY HERE WILL BE THE WELL BELOW NORMAL TEMPERATURES EXPECTED THROUGH THE WORK WEEK. MODELS HAVE BEEN CONSISTENT WITH H8 TEMPS IN THE -12 TO -15C RANGE AND LOW-LEVEL THICKNESSES BOTTOMING OUT TO AROUND 1240M WEDNESDAY NIGHT...60 TO 70 METERS BELOW NORMAL! HIGHS TUESDAY THROUGH THURSDAY IN THE LOWER TO MID 30S TO LOWER 40S. LOWS IN THE TEENS AND 20S. TEMPERATURES WILL BEGIN TO MODERATE ON FRIDAY AS THE COLD UPPER TROUGH BEGINS TO LIFT NORTHEAST AND OUT OF THE REGION. HOWEVER... THIS WARMING TREND WILL NOT LAST LONG AS AMPLIFYING SHORTWAVE ENERGY DIVING DOWN THE BACK SIDE OF THE EASTERN US TROUGH WILL BRING A REINFORCEMENT OF ARCTIC AIR INTO THE CAROLINAS LATE FRIDAY AND INTO SATURDAY. SOME OF THE MEDIUM RANGE MODELS INDICATE A POTENTIAL FOR SOME FROZEN PRECIP AS THE UPPER WAVE TRACKS THROUGH THE REGION. HOWEVER SINCE MOISTURE IS TYPICALLY LIMITED IN NW FLOW EVENTS...WILL KEEP FORECAST DRY FOR NOW. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/...
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AS OF 100 PM SUNDAY... WITH A A DEEPENING SURFACE LOW OFF THE S COAST...PRECIP CONTINUES TO SPREAD INLAND ACROSS THE NC COASTAL PLAIN. RAIN HAS BEEN MIXING WITH OR COMPLETELY CHANGING TO SLEET AND SNOW ALONG AN AXIS FROM KFAY TO KRWI. NEAR TERM MODELS SHOW THIS CONTINUING THROUGH 22Z OR SO BEFORE PRECIP ENDS FROM WEST TO EAST AND THE NORTHEASTERLY WINDS BECOME NORTHWESTERLY. CEILINGS HAVE ACTUALLY REMAINED ABOVE 2000 FT FOR THE MOST PART...AND VFR CONDITIONS HAVE EVEN BEEN PREDOMINATE AT MANY SITES. OUTSIDE OF THE HEAVIEST PRECIP...EXPECT THIS TREND TO CONTINUE THROUGH THIS EVENING AND OVERNIGHT. A FEW WIND GUSTS TO 25 KT OR SO WILL BE POSSIBLE THIS AFTERNOON AS THE LOW CONTINUES TO DEEPEN AND PASS BY THE NC COAST. SOME MVFR VSBYS ARE ALSO POSSIBLE FROM KFAY TOP KRWI LATE TONIGHT WHERE IT HAS BEEN PRECIPITATION ALL DAY...ALTHOUGH GUIDANCE DOESN`T SHOW MUCH REPORT AND CONFIDENCE IS LOW AT THIS POINT. A SOUTHWEST WIND WILL DEVELOP ON MONDAY AHEAD OF A STRONG DISTURBANCE DROPPING IN FROM THE NORTHWEST. WIND GUSTS NEAR 20KT AND SHOWERS WILL INCREASE DURING THE AFTERNOON HOURS. OUTLOOK...AFTER THE DISTURBANCE ON MONDAY PASSES BY...THE REMAINDER OF THE WEEK SHOULD BE MOSTLY VFR...WITH GUSTY NORTHWEST WINDS EACH DAY.
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&& .RAH WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR NCZ042-043-077-078-088-089. && $$ SYNOPSIS...BADGETT NEAR TERM...BADGETT/SMITH SHORT TERM...BADGETT/CBL LONG TERM...CBL AVIATION...22

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