675 FXUS62 KILM 111648 AFDILM AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 1148 AM EST TUE FEB 11 2014 .SYNOPSIS... A MAJOR WINTER STORM IS EXPECTED ACROSS THE AREA THROUGH WEDNESDAY NIGHT...WITH LARGE ICE ACCUMULATIONS EXPECTED INLAND. ARCTIC HIGH PRESSURE WILL NOSE ITS WAY INTO THE AREA THROUGH TONIGHT. A SERIES OF LOW PRESSURE SYSTEMS WILL TRACK ALONG A STALLED FRONT TO OUR SOUTH AND OFFSHORE TUESDAY THROUGH THURSDAY. DRIER WEATHER WILL FINALLY RETURN TO THE AREA FRIDAY AND PERSIST THROUGH THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1145 AM TUESDAY...HAVE UPGRADED THE WINTER WEATHER ADVISORY FOR THE CAPE FEAR REGION TO A WINTER STORM WARNING. UP TO ONE- QUARTER INCH OF FREEZING RAIN IS POSSIBLE THOUGH TONIGHT. OTHERWISE...NO CHANGES FROM 1100 AM...AND THAT DISCUSSION IS BELOW: AS OF 1100 AM TUESDAY...RAIN...SLEET...SNOW...AND FREEZING RAIN BEGINNING TO OVERSPREAD THE AREA...AS THE REGION BRACES FOR A LONG DURATION...MAJOR WINTER WEATHER EVENT. EVENT BEGINNING TODAY IS FORMED DUE TO THE INTERACTION OF A RIDGE OF HIGH PRESSURE CENTERED OVER THE MID-ATLANTIC WHICH IS WEDGING DOWN THE EAST COAST...AND MOISTURE OVERRUNNING THIS COLD DOME DUE TO MOIST SW FLOW ABOVE 5 KFT. THE COMBINATION OF THESE FEATURES PROMOTES INCREASING SATURATED ISENTROPIC LIFT...WHICH IS PRIMARILY RESPONSIBLE FOR THE PRECIPITATION BREAKING OUT OVER THE AREA THIS MORNING. IT IS PROGGED TO BE A COMPLEX AND DIFFICULT EVENT...WITH PORTIONS OF THE CWA EXPERIENCING ALL TYPES OF PRECIP TODAY. CURRENT OBSERVATIONS SHOW TEMPERATURES BELOW 32 ALONG AND NORTH OF A LINE FROM ABOUT DARLINGTON, SC...TO WHITEVILLE, NC...TO SURF CITY, NC. THIS FREEZING LINE DOES NOT DEMARCATE THE RAIN/SNOW LINE HOWEVER...AS A WARM TONGUE EXISTS AT AROUND 875MB /4200 FT AGL/ WHERE TEMPS REACH 1-3C. THERE IS A SIGNIFICANT GRADIENT ACROSS THE AREA HOWEVER...AS 12Z SOUNDING FROM MHX HAD A WARM NOSE TEMP OF ABOUT 0.5C...WHILE CHS SHOWED ONE REACHING ALMOST 8C! AS COOL AIR FLOWS ALMOST LETHARGICALLY SOUTHWARD DUE TO THE AGEOSTROPHIC DRAINAGE FROM THE HIGH PRESSURE...FREEZING LINE WILL DROP INTO SOUTH CAROLINA AND TOWARDS THE SOUTHERN EDGE OF THE CWA. MHX SOUNDING SUPPORTS MORE SLEET THAN FREEZING RAIN...WHILE CHS WOULD SUGGEST MORE FREEZING RAIN. THUS...THE ILM CWA WILL BE IN THAT TRANSITION ZONE...WHERE ALL PRECIP TYPES ARE EXPECTED. IN FACT...THIS IS OCCURRING PRESENTLY AS EVIDENCED BY A CLEAR ZONE OF LOW CORRELATION COEFFICIENT VALUES ON THE KLTX 0.5 DEGREE SCAN...MATCHING WELL WITH OBSERVATIONS RECEIVED INTO THE WFO SO FAR TODAY. SO THE BIGGEST...AND MOST DIFFICULT...QUESTION IS HOW THE SITUATION WILL EVOLVE TODAY. NAM BUFR SOUNDINGS HAVE A GOOD HANDLE THIS MORNING...OTHER THAN BEING A DEGREE WARM IN THE MHX WARM NOSE FROM 7AM. ISENTROPIC LIFT WILL MAXIMIZE AT 290K AND 295K THROUGH THIS AFTN...OCCURRING CONCURRENTLY WITH WEAK BUT PRESENT FRONTOGENESIS IN THE 800-700MB LAYER. IN FACT...THIS FGEN BANDING PRESENT ON CROSS SECTIONS MATCHES WELL WITH THE CURRENT RADAR DEPICTION OF A HEAVIER BAND OF PRECIP SETTING UP ALONG AND JUST EAST OF I-95. HAVE INCREASED FORECAST SNOW TOTALS TODAY NW OF THE LINE MENTIONED ABOVE...AND ADDED UP TO ONE-TENTH OF AN INCH OF GLAZE IN THE NC COUNTIES SE OF THAT LINE. EXPECT PRECIP TO CONTINUE WITH BURSTS OF MORE INTENSE SNOW/SLEET FROM THE WESTERN PEE DEE NORTHEAST TOWARDS PENDER COUNTY THROUGH THIS EVE...BEFORE BEST FRONTOGENESIS SHIFTS AWAY FROM THE AREA AND SOME DRYING OCCURS TONIGHT. HAVE CONTINUED TREND OF RAMPING POP DOWNWARD A FEW HOURS EITHER SIDE OF MIDNIGHT...BEFORE INCREASING ONCE AGAIN FROM THE SW AS THE PRIMARY AREA OF LOW PRESSURE BEGINS TO MOVE TOWARDS THE REGION. IT IS WITH THIS SECOND ROUND OF PRECIP (LASTING WELL BEYOND THIS PERIOD) THAT THE HEAVIEST FREEZING RAIN IS EXPECTED THANKS TO INCREASING WAA ABOVE THE COLD DOME. WITH ALL THAT SAID...WINTER WEATHER HEADLINES REMAIN UNCHANGED...AND EXPECT ONE-HALF TO TWO INCHES OF SNOWFALL FROM ABOUT HARTSVILLE TO BURGAW...WITH ISOLATED HIGHER TOTALS IN NORTHERN BLADEN AND ROBESON COUNTIES. LIGHT ICING IS POSSIBLE SE OF THERE TO ABOUT A LINE FROM KINGSTREE TO SOUTHPORT...WITH PRIMARILY RAIN TODAY ALONG THE GRAND STRAND TOWARDS THE SOUTH SANTEE RIVER. FREEZING RAIN WILL DEVELOP AT THE END OF THE PERIOD. TEMPS HAVE PEAKED FOR THE DAY...WITH THE SLOW FALL TO CONTINUE AS DESCRIBED ABOVE. TEMPS IN THE LOW 30S NORTH...UPPER 30S FAR SOUTH...WILL DROP TO AROUND 30...UPPER 20S FAR NW...WITH VERY LITTLE DIURNAL RANGE DEVELOPING TODAY. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... AS OF 3 AM TUESDAY...STILL A FEW DEVILS IN THE DETAILS IN THE OTHERWISE HIGH IMPACT STORM AFFECTING US THROUGH THE PERIOD. RIGHT AT 12Z WED THERE IS AN INTERESTING DIFFERENCE IN THE STRENGTH OF THE COLD AIR ALONG THE COAST WITH THE WRF MUCH STRONGER...AND ACTUALLY IMPLYING THAT COASTAL LOCALES...MAINLY NC...COULD HAVE A PROLONGED PERIOD OF FZRA. FOR NOW HAVE BLENDED THIS WITH THE MORE TEMPERED GFS AND PREV FORECAST. IT SEEMED PRUDENT TO RAISE WINTER WEATHER ADVISORY FOR ALL AREAS NOT IN THE WSW AS ANY FREEZING RAIN AT ALL SATISFIES ADVISORY. MEANWHILE FAR INTERIOR ZONES IN THE SLEET/SNOW ZONE FOR THE MOST PART. ACCUM FCST NOT CHANGED SIGNIFICANTLY AND THE SPECTER OF THE SLEET CASTS PLENTY OF UNCERTAINTY ON THE ACTUAL SNOWFALL FORECAST ANYWAY. 1-2 INCHES STILL EXPECTED BURGAW TO ELIZABETHTOWN TO SOUTH OF DILLON AND SRN DARLINGTON. NORTH OF THERE WILL BE A STRIP OF 2-3 INCHES AND FAR NRN MARLBORO THE BULLSEYE OF ABOUT 4 INCHES OR A LITTLE MORE. OTHER THAN THE AFOREMENTIONED POSSIBILITY OF SOME MINOR COASTAL FREEZING RAIN THE OUTLOOK HASNT CHANGED MUCH FOR WESTERN ZONES. SWATH OF 0.5-0.75" MAX ALONG OUR WESTERNMOST ZONES AND A CATEGORY LOWER TO THE EAST...QUARTER TO HALF INCH AND EVEN LOWER GRADATION TENTH TO QUARTER INCH FOR ALL BUT AREAS IN ADVISORY. A PICTURE WORTH A THOUSAND AFD WORDS SO PLEASE REFER TO THE OFT UPDATED GRAPHICS ON OUR WEBSITE. WINTRY PRECIP MAY LINGER INTO WEDNESDAY NIGHT BUT TEND TO HAVE A LIMITED ABILITY TO ACCUMULATE WITH A LOSS OF MOISTURE IN THE DENDRITIC GROWTH ZONE. MID AND UPPER LEVELS REMAIN DRY THURSDAY AS WELL BUT THE VERY POWERFUL MID LEVEL TROUGH AND VORT SWINGS THRU...AND COULD POSSIBLY WRING OUT FREEZING DRIZZLE OR FLURRIES. && .LONG TERM /FRIDAY THROUGH MONDAY/... AS OF 3 PM MONDAY...LOW PRESSURE WILL BE LIFTING OFF TO THE NORTHEAST ON THURS WITH LINGERING PCP THROUGH THE DAY. SHOULD BE MORE IN THE WAY OF RAIN THAN MIXED AS AIR MASS WARMS SLIGHTLY BUT PLACES WELL INLAND MAY CONTINUE TO MIX UNTIL LATE DAY. PLENTY OF DRY AND COOL AIR WILL MOVE IN BEHIND THE LOW AS HIGH PRESSURE BUILDS IN BRIEFLY. THIS WILL LEAD TO CLEARING SKIES THROUGH THE END OF THE DAY ON THURS INTO EARLY FRI. THE HIGH WILL RIDGE UP FROM THE SOUTH THURS NIGHT THROUGH EARLY FRI BUT WINDS WILL BACK TO THE W-SW THROUGH FRI AHEAD OF NORTHERN STREAM SYSTEM APPROACHING THE CAROLINAS. THIS NORTHERN STREAM SYSTEM WILL DIG DOWN FROM THE GREAT LAKES THROUGH FRI SWEEPING A COLD FRONT THROUGH THE COASTAL CAROLINAS. LATEST GFS SHOWING A FAIRLY POTENT SHORTWAVE DIGGING FAR ENOUGH SOUTH TO LEND TOWARD GREATER CHC OF PCP ON FRI ASSOCIATED WITH COLD FRONT PASSAGE. AS THIS SYSTEM SHIFTS FURTHER OFF SHORE THROUGH FRIDAY NIGHT...THE DEEP DRY W-NW FLOW BEHIND IT WILL SCOUR OUT ALL CLOUDS AND PCP LEADING TO A DRIER AND COOLER FIRST HALF OF THE WEEKEND WITH MORE IN THE WAY OF SUN THAN CLOUDS FOR THE MOST PART. HIGH PRESSURE WILL ONCE AGAIN RIDGE UP FROM THE SOUTH ON SATURDAY WITH THE GFS DOES SHOW ANOTHER SHORTWAVE PUSHING A COLD FRONT THROUGH SAT NIGHT INTO EARLY SUNDAY WHICH LOOKS LIKE IT SHOULD PRODUCE MORE IN THE WAY OF CLOUDS THAN PCP. HIGH PRESSURE WILL BUILD DOWN FROM THE NORTH OVER THE SOUTHEAST THROUGH EARLY NEXT WEEK...SUNDAY INTO MONDAY. TEMPS WILL BE BELOW NORMAL THE FIRST HALF OF THE EXTENDED PERIOD BUT WILL WARM HEADING INTO THE LATTER HALF OF THE WEEKEND INTO EARLY NEXT WEEK AS HIGH PRESSURE BUILDS OVER THE CAROLINAS WITH SLIGHTLY WARMER MID FEBRUARY SUNSHINE...REACHING CLOSER TO 60 SUNDAY AND MONDAY. && .AVIATION /18Z TUESDAY THROUGH SUNDAY/... AS OF 12Z TUESDAY...A BAND OF MAINLY LIGHT RAIN/SLEET WITH IFR/LIFR IS AFFECTING THE TERMINALS THIS MORNING. FLIGHT CONDITIONS HAVE SHOWN AN IMPROVEMENT OVER THE PAST SEVERAL HOURS AS SURFACE HIGH PRESSURE BUILDS S. ALL OF THE LATEST MODELS INCREASE THE PRECIPITATION TODAY THUS IT APPEARS IFR/LIFR WILL RE-DEVELOP AT ALL TERMINALS LATER THIS MORNING AND PERSIST INTO THIS EVENING. THE LOW LEVEL AIRMASS WILL BECOME PROGRESSIVELY COLDER THIS TAF VALID PERIOD...THUS EXPECT PRECIPITATION TO TURN TO ALL SNOW AT KLBT THIS AFTERNOON...AND BECOME SLEET AT KFLO/KILM POSSIBLY AS EARLY AS THIS AFTERNOON...AND BY EVENING AT KCRE/KMYR. PRECIPITATION WILL TAPER OFF OVERNIGHT FROM WEST TO EAST. AS THE PRECIPITATION ENDS CIGS WILL IMPROVE TO MVFR AT KFLO AND VFR AT KLBT. COASTAL TERMINALS WILL LIKELY REMAIN IFR THROUGH 12Z. EXTENDED OUTLOOK...A WINTRY MIX WITH PREDOMINATELY IFR/LIFR CONDITIONS ARE EXPECTED THROUGH POSSIBLY THU MORNING. CONDITIONS IMPROVING TO VFR THU EVENING. FRI EVENING A CHANCE OF TEMPO SNOW SHOWERS/IFR. VFR SAT. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 1100 AM MONDAY...STRONG SMALL CRAFT ADVISORY REMAINS IN PLACE. WINDS AT THE LOCAL BUOYS ARE OBSERVED ABOVE 25 KTS...WITH GUSTS APPROACHING GALE FORCE. IT IS A BIT DISCONCERTING THAT WINDS ARE THIS STRONG ALREADY...SINCE AS THE GRADIENT TIGHTENS INTO TONIGHT WINDS WILL ONLY INCREASE FURTHER. STILL...ANTICIPATE ONLY INFREQUENT GALE FORCE GUSTS...AND WILL MAINTAIN JUST THE STRONGLY WORDED SMALL CRAFT ADVISORY...FOR WINDS 25-30 KTS FROM THE NE...AND SEAS RISING TO 7-10 FT TONIGHT. SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... AS OF 3 AM TUESDAY...SMALL CRAFT ADVISORY IN EFFECT THROUGH THE PERIOD. HIGH PRESSURE WEDGES EAST OF THE MOUNTAINS WHILE LOW PRESSURE SLOWLY DEVELOPS WELL OFF THE COAST AND ONLY MOVES SLOWLY. THIS KEEPS THE GRADIENT PINCHED. LATER IN THE DAY AND WEDNESDAY NIGHT A SECONDARY LOW MOVES OUT OF THE NE GOMEX AND SLIDES UP THE COAST. THIS SECONDARY MOVES A LITTLE CLOSER TO THE COAST AND COULD LEAD TO A SHORT DECREASE IN THE WINDS AND SEAS COULD LOWER AS WELL BUT STILL NEED ADVISORY. IN THE WAKE OF THIS LOW WINDS PICK BACK UP SINCE IT DEEPENS AS IT MOVES OFF TO THE NORTHEAST. LONG TERM /THURSDAY THROUGH SATURDAY/... AS OF 3 PM MONDAY...THE LOW WILL LIFT NORTH ON THURS WITH N-NW WINDS AS HIGH PRESSURE REACHES UP FROM THE SOUTH. THE WINDS WILL BACK TO W-SW BY FRI AHEAD OF COLD FRONT REACHING DOWN FROM NORTHERN STREAM SYSTEM. WINDS WILL VEER TO THE NW TO N THROUGH LATE FRIDAY AS COLD FRONT PASSES THROUGH WATERS AND FURTHER OFF SHORE. HIGH PRESSURE WILL BUILD BACK UP FROM THE SOUTH ON SATURDAY WITH LIGHTER WINDS AS GRADIENT RELAXES. OFF SHORE DECREASING W-NW WIND FLOW BEHIND LOW LATE THURS WILL ALLOW SEAS TO SUBSIDE THROUGH THURS NIGHT INTO FRI BUT SHOULD SEE ANOTHER SPIKE IN WINDS AND SEAS BY FRI. W-SW WINDS WILL INCREASE ON FRI AS GRADIENT TIGHTENS AHEAD OF APPROACHING COLD FRONT AND WILL STAY HIGHER AS FRONT PASSES FURTHER OFF SHORE FRI NIGHT...BUT WILL DIMINISH ONCE AGAIN BY SATURDAY AS HIGH PRESSURE REACHES UP INTO THE COASTAL WATERS FROM THE SOUTH. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...WINTER STORM WARNING UNTIL 7 AM EST THURSDAY FOR SCZ017-023- 024-032-033-053. WINTER WEATHER ADVISORY FROM 1 AM TO NOON EST WEDNESDAY FOR SCZ054-056. WINTER STORM WARNING FROM 7 PM THIS EVENING TO 7 AM EST THURSDAY FOR SCZ039-055. NC...WINTER STORM WARNING UNTIL 7 AM EST THURSDAY FOR NCZ087-096- 099-105. WINTER STORM WARNING UNTIL NOON EST WEDNESDAY FOR NCZ106>110. MARINE...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EST THURSDAY NIGHT FOR AMZ250-252-254-256. && $$ SYNOPSIS...MBB NEAR TERM...JDW SHORT TERM...MBB LONG TERM...RGZ AVIATION...MRR MARINE...JDW/MBB/RGZ