Area Forecast Discussion
Issued by NWS Wilmington, NC

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000 FXUS62 KILM 141724 AFDILM AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 123 PM EDT MON APR 14 2014 .SYNOPSIS... HIGH PRESSURE WILL MAINTAIN CONTROL OF THE WEATHER INTO TODAY. A COLD FRONT WILL MOVE ACROSS THE AREA TUESDAY...WITH INCREASING CHANCES FOR SHOWERS AND POSSIBLY THUNDERSTORMS LATE MONDAY INTO TUESDAY. HIGH PRESSURE WILL MOVE INTO THE AREA WEDNESDAY AND CONTROL AREA WEATHER INTO FRIDAY BEFORE CONDITIONS DETERIORATE IN ADVANCE OF A COLD FRONT THAT WILL MOVE THROUGH THE AREA SATURDAY NIGHT OR EARLY SUNDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1200 PM MONDAY...CURRENT RADAR IMAGERY SHOWS LIGHT SHOWERS MOVING ONSHORE AROUND THE WESTERN PERIPHERY OF HIGH PRESSURE WELL OFF THE ATLANTIC COAST. HAVE TRIMMED BACK POPS FOR OUR FAR WESTERN ZONES THIS AFTERNOON BASED ON RADAR TRENDS AND DRY MID-LEVEL AIR DEPICTED IN FCST SOUNDINGS. STILL EXPECT PCPN COVERAGE TO GRADUALLY INCREASE LATER TODAY INTO THIS EVENING AS DEPICTED BY HRRR AND OTHER HI RES MODELS. THE REST OF THE FORECAST STILL APPEARS ON TRACK ATTM. PREVIOUS DISCUSSION AS FOLLOWS... AS OF 1000 AM MONDAY...ANOTHER WARM DAY EXPECTED AS HIGH PRESSURE ONLY SLOWLY LOSES ITS GRIP ACROSS THE CAROLINAS...BUT MUCH MORE CLOUD COVER TODAY WILL KEEP TEMPS SEVERAL DEGREES COOLER THAN PREVIOUS DAYS. THIS CLOUD COVER IS DUE TO A COMBINATION OF INCREASED LOW LEVEL MOISTURE DUE TO ADVECTION OFF THE ATLANTIC...AND HIGH/MID CLOUDINESS AHEAD OF A STRONG COLD FRONT APPROACHING FROM THE WEST. THIS FRONT IS TRAILING FROM A CYCLONE MOVING UP THROUGH THE GREAT LAKES...AND ALTHOUGH ITS DIRECT IMPACTS WILL HOLD OFF UNTIL AFTER THIS PERIOD...CLOUDS AND SHOWERS WILL SLOWLY INCREASE IN COVERAGE TODAY. KLTX RADAR THIS MORNING HAS SHOWN A FEW SHOWERS TRYING TO MOVE ONSHORE FROM THE ATLANTIC ON S/SE WINDS...BUT MOST OF THESE ARE EVAPORATING AS THEY MOVE ACROSS THE COOLER SHELF WATERS...BEFORE COMING ONSHORE. EXPECT THIS TREND TO CONTINUE THROUGH THE AFTN...BUT COVERAGE AND INTENSITY OF THESE SHOWERS WILL LIKELY INCREASE AS MOISTURE AND INSTABILITY BECOME MORE SIGNIFICANT...AND AN ISOLATED RUMBLE OF THUNDER IS POSSIBLE. MOST OF THE HIGH RES MODELS...HRRR/ARW/WRF...SHOW A SIMILAR PATTERN OF SHOWERS MOVING ONSHORE BEFORE ROTATING NORTH AROUND THE HIGH PRESSURE...AND DUE TO THIS AGREEMENT HAVE SHOWN POP GRIDS WHICH MATCH THIS IDEA. AT THE SAME TIME...PRECIP WILL SLOWLY INCREASE FROM THE WEST AS THE COLD FRONT APPROACHES. MID-LEVEL DRYNESS WILL BE TOUGH TO OVERCOME...BUT BY TONIGHT FORECAST PROFILES SATURATE AND RAIN SHOWERS ARE EXPECTED TO BECOME NUMEROUS ACROSS THE AREA. TOTAL QPF WILL BE LIGHT THROUGH THE DAY...AS THE HEAVIEST RAIN HOLDS OFF UNTIL AFTER THE NEAR TERM PERIOD. TEMPS TODAY WILL RISE INTO THE MID/UPR 70S...HIGHEST INLAND. LOWS TONIGHT WILL BE TEMPERED BY CONTINUING SOUTHERLY WINDS AND INCREASING RAIN SHOWERS/CLOUD COVER...SO EXPECT A RATHER MINIMAL DIURNAL RANGE WITH MINS IN THE UPPER 60S AT THE COAST...MID 60S INLAND. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 330 AM MONDAY...MID TO UPPER TROUGH EXTENDING DOWN FROM THE GREAT LAKES TO THE GULF COAST WILL PUSH A COLD FRONT EAST THROUGH THE CAROLINAS ON TUESDAY. INCREASINGLY WARM AND HUMID AIR MASS AHEAD OF THE FRONT WITH DEWPOINT TEMPS INTO THE MID 60S...WILL SET THE STAGE FOR INCREASED SHWR/TSTM ACTIVITY. LLJ UP TO 45 KTS COMBINED WITH MID TO UPPER LEVEL SUPPORT INCLUDING A STRONG JET WILL AID IN CONVECTIVE DEVELOPMENT. SPC CONTINUES TO HOLD US IN SLIGHT RISK WITH MAIN THREAT AS DAMAGING WIND AND POTENTIAL FOR A TORNADO IN SOME LINE SEGMENTS AND EMBEDDED SUPERCELLS TUES AFTN. THE CLOUDS MAY COME INTO PLAY AS A LIMITING FACTOR WORKING AGAINST THE CONTINUED WAA THROUGH TUES...BUT TEMPS WILL ALREADY BE WELL INTO THE 60S TO START THE DAY AND SHOULD MAKE IT WELL INTO THE 70S IN MOST PLACES. TEMPS SHOULD MODERATE WITH PLENTY OF MID TO HIGH CLOUDS OVER THE AREA AHEAD OF THE ACTUAL FRONT. BEST LIFT WILL COME AS FRONT MOVES THROUGH FROM WEST TO EAST THROUGH LATE AFTN INTO THE EVENING. A TOTAL CHANGE IN AIR MASS WILL COME AS HIGH PRESSURE BUILDS IN BEHIND FRONT THROUGH WED MORNING. PLENTY OF DRY AIR AND SUBSIDENCE WILL BE IN PLACE WITH CLEARING SKIES THROUGH DAYBREAK WED. PCP WATER VALUES UP AROUND 1.8 INCHES AHEAD OF FRONT LATE TUES WILL DROP TO AS LOW AS A QUARTER OF AN INCH BY WED MORNING. 850 TEMPS WILL PLUMMET FROM CLOSE TO 13C DOWN NEAR 4C BY WED MORNING. THIS STRONG CAA WILL BRING TEMPS DOWN ABOUT 20 DEGREES F FROM TUES TO WED. TEMPS BY WED MORNING WILL BE DOWN IN THE 30S OVER SOME PLACES INLAND. DEWPOINT TEMPS WILL DROP FROM THE MID 60S AHEAD OF THE FRONT DOWN TO MID 20S BY TUES AFTN. OVERALL EXPECT COOL NORTHERLY WINDS TO BE OFFSET BY PLENTY OF APRIL SUNSHINE TO PRODUCE TEMPS CLOSE TO 60. A PINCHED GRADIENT FLOW WILL KEEP N-NE FLOW REINFORCING THE COOL AIR THROUGH THURS NIGHT. TEMPS SHOULD DROP ONCE AGAIN INTO THE 30S MANY PLACES INLAND. && .LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 330 AM MONDAY...COOL AND DRY HIGH PRESSURE WILL BE IN PLACE AS WEDGE LIKE PATTERN DEVELOPS THURS INTO FRI WITH TROUGH OFF SHORE. THE GREATER ON SHORE COMPONENT TO THE FLOW WILL ALLOW MOISTURE TO INCREASE SLIGHTLY THROUGH THURS AND FURTHER INTO FRIDAY. PCP WATER VALUES REMAIN DOWN BELOW A HALF INCH THROUGH THURS BUT AS LOW PRESSURE DEVELOPS AND RISES UP FROM THE GULF COAST THROUGH FRI...THE SHALLOW COOL AND DRY AIR WILL BE OVERRUN WITH SOUTHERLY WINDS THROUGH THE LOW LEVELS. THIS WILL PROVIDE INCREASE ISENTROPIC LIFT THROUGH THE LATE THURS INTO FRI WITH LOW CLOUDS AND POSSIBILITY OF PCP. THE MOISTURE WILL REMAIN SHALLOW...BASICALLY BELOW 5K FT. AT THE SAME TIME A NORTHERN STREAM SYSTEM MOVES EAST DRAGGING A COLD FRONT TOWARD THE CAROLINAS. THIS SYSTEM MAY KEEP THE BEST MOISTURE AND LIFT OFF SHORE THROUGH FRI LEAVING A WEAKENING COLD FRONT MOVING THROUGH ON SATURDAY. KEPT POPS UP ON FRI ALTHOUGH NOT CONFIDENT THAT ENOUGH MOISTURE AND LIFT WILL REACH THIS FAR NORTH FROM GULF LOW BEFORE MOVING OFF SHORE. MAY END UP BEING MUCH MORE IN THE WAY OF CLOUDS THURS INTO FRI THAN PCP. TEMPS WILL REMAIN BELOW NORMAL IN CAA INITIALLY AND THEN CLOUDS WILL KEEP TEMPS LOWER. HIGH PRESSURE WILL BUILD IN BEHIND FRONT THROUGH SATURDAY INTO SUNDAY. ANOTHER COLD FRONT MAY MOVE EARLY NEXT WEEK WITH INCREASED CLOUDS AND CHC OF PCP BY SUN NIGHT. TEMPS WILL REACH BACK UP TOWARD NORMAL THROUGH THE WEEKEND. && .AVIATION /18Z MONDAY THROUGH SATURDAY/...
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AS OF 18Z...A STABLE LAYER AROUND 6500 FT HAS KEPT THE ATMOSPHERE A BIT CAPPED...BUT THAT STABLE LAYER SHOULD DISSIPATE THIS EVENING WITH MORE WIDESPREAD CONVECTION EXPECTED TO BREAK OUT AFTER MIDNIGHT. CEILINGS WILL LOWER WITH THE COMMENCEMENT OF PRECIP...POSSIBLY IFR CONDITIONS INLAND. WINDS WILL STAY ABOVE 7-8 KTS OVERNIGHT...IN FACT THEY WILL INCREASE TOWARD MORNING AS THE GRADIENT TIGHTENS AHEAD OF THE FRONT. TUESDAY...CONVECTION WILL BE IN AND OUT WITH DECENT COVERAGE. MODELS INDICATE WE WILL GET ENOUGH SOLAR INSOLATION AND WARM AIR ADVECTION TO SUPPORT POSSIBLE STRONG STORMS AFTER MIDDAY...STARTING FROM THE SOUTHWEST. CAPE COULD APPROACH 1000 J/KG WITH 55 KTS AT 2500 FEET. THE MARINE LAYER MAY SPARE THE COAST FROM STRONG STORMS IF THEY WAIT TO ARRIVE BY LATE AFTERNOON OR EVENING. EXTENDED OUTLOOK...BECOMING VFR TUESDAY NIGHT...CONTINUING THROUGH THURSDAY. POSSIBLE FOG/STRATUS FRIDAY AND SATURDAY...LOW CONFIDENCE.
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&& .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 1000 AM MONDAY...HIGH PRESSURE CENTERED WELL OFFSHORE CONTINUES TO RIDGE BACK TOWARDS THE SOUTHEAST...BUT IS SLOWLY LOSING ITS GRIP OVER THE AREA. THIS IS DRIVING S/SE WINDS OF 10-15 KTS AT THE LOCAL BUOYS...WHICH WILL GRADUALLY VEER MORE TO THE SOUTH AND INCREASE TO 15-20 KTS TONIGHT. LOCAL SWAN GUIDANCE IS ABOUT 1 FT TOO HIGH WITH CURRENT SEAS...SO HAVE BLENDED DOWN WITH WNAWAVE TO MORE ACCURATELY REPRESENT ONGOING CONDITIONS...AND SHOW A SLOWER RISE IN WAVE HEIGHTS TONIGHT. STILL EXPECT SEAS TO BUILD TO 4-6 FT TONIGHT...AND A SMALL CRAFT ADVISORY REMAINS IN EFFECT...BEGINNING AT 2 AM TUESDAY. SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 330 AM MONDAY...SMALL CRAFT CONDITIONS WILL PERSIST THROUGH MUCH OF THE PERIOD IN STRONG SOUTHERLY WINDS AHEAD OF A COLD FRONT AND NORTHERLY SURGE BEHIND COLD FRONT TUES NIGHT THROUGH WED NIGHT. MAY REACH GALE CRITERIA TUES NIGHT IN COLD SURGE AS HIGH PRESSURE BUILDS IN BEHIND COLD FRONT. WINDS WILL INCREASE UP TO 20 TO 25 KT TUESDAY BEFORE RAPIDLY SHIFTING TO THE NORTH AND INCREASING TO 25 TO 30 KT LATE TUESDAY NIGHT. SEAS WILL CONTINUE TO BUILD THROUGH TUES FROM 5 TO 7 FT UP TO 6 TO 8 FT TUES EVENING. AFTER THE COLD FRONT MOVES THROUGH TUESDAY EVENING A STRONG NORTHERLY FLOW UP TO 30 KTS WILL KEEP SEAS UP POSSIBLY TO 9 FT IN OUTER WATERS OVERNIGHT TUES INTO EARLY WED. GRADIENT WILL REMAIN TIGHT THROUGH WED AS NORTHERLY WINDS VEER SLIGHTLY TO THE NE AS HIGH PRESSURE RIDGES DOWN THROUGH THE CAROLINAS FROM THE NORTHEAST. LONG TERM /THURSDAY THROUGH FRIDAY/... AS OF 330 AM MONDAY...HIGH PRESSURE WILL CONTINUE TO RIDGE DOWN THROUGH THE CAROLINAS WHILE A WAVE OF LOW PRESSURE DEVELOPS OFF SHORE ALONG LINGERING COLD FRONT. STRONG NORTHERLY SURGE OF COLD AIR AND TIGHTENED GRADIENT FLOW WILL MAINTAIN N-NE WINDS CLOSER TO 20 KTS INITIALLY ACROSS THE WATERS THROUGH THURSDAY. WINDS WILL LIGHTEN AND VEER SLIGHTLY LATE THURS REMAINING CLOSER TO 15 KTS THROUGH FRI. SEAS SHOULD DROP DOWN BUT REMAIN 4 TO 6 FT THROUGH THURS NIGHT INTO FRI. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...SMALL CRAFT ADVISORY FROM 2 AM TUESDAY TO 6 PM EDT WEDNESDAY FOR AMZ250-252-254-256. && $$ SYNOPSIS...SHK NEAR TERM...JDW/BJR SHORT TERM...RGZ LONG TERM...RGZ AVIATION...43

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