MHX issues Area Forecast Discussion (AFD) 509 FXUS62 KMHX 141951 AFDMHX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEWPORT/MOREHEAD CITY NC 351 PM EDT MON JUL 14 2014 .SYNOPSIS... A TROUGH OF LOW WILL LINGER INLAND THROUGH TUESDAY. A COLD FRONT WILL APPROACH FROM THE WEST AND SLOWLY CROSS THE REGION TUESDAY NIGHT AND WEDNESDAY. THE FRONT WILL STALL OFF THE COAST THURSDAY AND FRIDAY THEN DISSIPATE OVER THE WEEKEND AS OFFSHORE HIGH PRESSURE BECOMES DOMINANT. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... AS OF 330 PM MONDAY...A FEW ISOLATED SHOWERS FORMING ALONG THE SEA BREEZE JUST INLAND WITH ADDITIONAL THUNDERSTORMS FORMING AHEAD OF PIEDMONT TROUGH FURTHER INLAND SOUTHEAST OF RALEIGH. WILL CARRY 30 PCT POPS INLAND AND 20 PCT COAST THROUGH THE EVENING HOURS AS 3KM HRRR AND 4KM WRF CONTINUE TO INDICATE ACTIVITY THRU LATE EVENING. THE RAP...NAM12 AND GFS ALL HINT AT SOME ADDITIONAL SHOWERS MOVING ALONG THE COASTAL COUNTIES LATE TONIGHT AND HAVE SMALL POPS FOR THAT TIME PERIOD AS WELL. SOUTHWEST WINDS SHOULD AGAIN HOLD MIN TEMPS IN THE MUGGY MID/UPPER 70S. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/... AS OF 335 PM MONDAY...SURFACE TROUGH INLAND WILL CONTINUE TO SHARPEN ON TUESDAY AND DEEP LONGWAVE TROUGH WORKS ITS WAY TO THE EAST. WITH DEEP GULF MOISTURE FEED PUSHING PRECIPITABLE WATER VALUES TO NEAR 2 INCHES...EXPECT SHOWERS AND TSTMS TO DEVELOP DURING THE AFTERNOON AND EVENING HOURS. SOME QUESTION WILL THE AMOUNT OF DESTABILIZATION THAT WILL BE ABLE TO OCCUR GIVEN ANY MORNING CLOUDS AND PRECIPITATION...BUT MODEL SOUNDINGS SHOW CAPES OF ROUGHLY 1500-2000 J/KG AND LI VALUES TO AROUND -5 OR -6 AS NUMERICAL GUIDANCE SHOWS MAX TEMPS APPROACHING 90 INLAND. SPC CONTINUES TO HAVE AREAS JUST INLAND IN A SLIGHT RISK FOR TOMORROW AND WILL MONITOR. WILL SLOWLY RAMP UP POPS INTO THE LIKELY RANGE INLAND BY THE AFTERNOON HOURS ON TUESDAY. && .LONG TERM /TUESDAY NIGHT THROUGH MONDAY/... AS OF 330 PM MON...A LONG WAVE TROUGH ACROSS THE EASTERN HALF OF THE CONUS WILL BE THE DOMINATING SYNOPTIC REGIME THROUGH THE PERIOD. STRONG SHORTWAVE WILL BE SWING THROUGH THE GREAT LAKES REGION HELPING TO PUSH LOWER HEIGHTS TOWARDS THE AREA FROM THE NORTHWEST. THIS WILL PUT THE AREA IN FAVORABLE LARGE SCALE LIFT TUE NIGHT INTO WED AS ATTENDANT SFC COLD FRONT SLOWLY MOVES INTO E NC. THE RIDGE ALONG THE SOUTHEASTERN COAST WILL BE SHUNTED WELL OFFSHORE TUES THOUGH IT WILL HELP FOCUS A RICH SOUTHWESTERLY MOISTURE STREAM FROM THE GULF OF MEXICO AND SOUTHWESTERN ATLANTIC OCEAN THROUGH WED. FORECAST SOUNDINGS INDICATE PWATS RAMPING BACK ABOVE 2 INCHES LATE TUES INTO EARLY WED. MAINTAINED PREVIOUS FCST OF LIKELY POPS TUE NIGHT. LAYER MOISTURE CONVERGENCE OF AROUND 17 G/KG AND PWATS ABOVE 2 IN WILL BE MAXIMIZED TUE NIGHT PER 14/12Z MODELS SO EXPECT HEAVIEST AND MOST WIDESPREAD PRECIP TO FALL THEN. THE COLD FRONT WILL BE SLOW TO MOVE THROUGH E NC WED BUT HAVE CONTINUED SLOWLY DECREASING POPS FROM WEST TO EAST...AS WE WILL LIKELY BE ON THE WEST SIDE OF THE STALLED BOUNDARY BY 00Z THURS SAVE FOR THE COASTAL WATERS. THICKNESSES STILL RATHER HIGH WED THOUGH WIDESPREAD CLOUDS AND PRECIP WILL HOLD TEMPS INTO THE MID 80S INLAND TO LOW 80S COAST. THERE IS THE CHANCE FOR ORGANIZED THUNDERSTORMS TO DEVELOP WED...AS THE AREA WILL BE UNDER FAVORABLE RIGHT ENTRANCE REGION OF EASTWARD ADVANCING JET STREAK...PRODUCING DEEP LAYER SHEAR OF ~30-35 KT. THE LIMITING FACTOR HOWEVER MAY BE INSTABILITY...AS PLENTY OF CLOUDS AND FAIRLY WEAK LAPSE RATES WOULD PROHIBIT VIGOROUS UPDRAFTS. NEVERTHELESS...THERE IS A SMALL CHANCE THAT THERE COULD BE AN ISOLATED SEVERE STORM OR TWO BEFORE THE DAY IS OVER. STILL MINOR DIFFERENCES APPEAR IN THE EXTENDED RANGE GUIDANCE WITH REGARDS TO THE SFC AND UPPER AIR PATTERN LATE IN THE WEEK...HOWEVER ALL MODELS IN AGREEMENT ON LONG WAVE TROUGH REMAINING DOMINANT THROUGH NEXT WEEKEND. DETERMINISTIC MODELS CONVERGING ON KEEPING THE AREA DRY THUR AND FRI...THOUGH ENSEMBLE MOS STILL INDICATES SOME SPREAD WITH REGARDS TO POPS...SO KEPT IN SLIGHT CHANCE PRECIP THUR. FRI SFC FLOW RETURNS TO MORE SE DIRECTION SO COULD BE SLIGHT BETTER CHANCE OF SHOWERS/STORMS ALONG SEA BREEZE BOUNDARY. BETTER CHANCE OF PRECIP NEXT WEEKEND AND MAINTAINED CHANCE POPS EVERYWHERE AS BROAD SW FLOW RETURNS WITH INC MOISTURE. && .AVIATION /20Z MONDAY THROUGH SATURDAY/... SHORT TERM /TONIGHT AND TUESDAY/... AS OF 1250 PM MONDAY...GENERALLY VFR CONDITIONS WILL PREVAIL OUTSIDE OF SOME WIDELY SCATTERED TSTMS INLAND AT THE TAF SITES...WHICH COULD TEMPORARILY REDUCE CEILINGS AND VSBYS. ALTHOUGH SOME OF THE NUMERICAL GUIDANCE SHOWS SOME MVFR FOG...WILL KEEP OUT FOR NOW AS A DECENT SOUTHWEST FLOW SHOULD MIX THE BOUNDARY LAYER SUFFICIENTLY TO PRECLUDE WIDESPREAD DENSE FOG. LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... AS OF 345 PM MON...INCREASING CHANCES FOR RAIN AND THUNDERSTORMS WHICH COULD PRODUCE SUB-VFR CONDITIONS THROUGH WED...WITH BEST CHANCES FOR WIDESPREAD RAIN/EMBEDDED THUNDER AND LOW CEILINGS/VSBYS TUES NIGHT. DRIER CONDITIONS EXPECTED TO MOVE IN WED AFTERNOON THROUGH THURS AS HIGH PRESSURE BUILDS INTO THE REGION FROM THE NORTH AND THE BOUNDARY REMAINS STALLED TO THE EAST AND SOUTH. && .MARINE... SHORT TERM /TONIGHT AND TUESDAY/... AS OF 340 PM MONDAY...NO REAL CHANGE IN THINKING AS GRADIENT CONTINUES TO TIGHTEN IN RESPONSE TO SHARPENING INLAND TROUGH WITH HIGH PRESSURE LINGERING OFFSHORE. EXPECT SOUTHWEST WINDS 15 TO OCCASIONALLY 20 KNOTS TONIGHT INTO TUESDAY. PER LOCAL SWAN/NWPS AND WAVEWATCH...SEAS OF 2 TO 4 FEET THIS EVENING SHOULD BUILD TO 3 TO 5 FEET LATE TONIGHT AND TUESDAY. SEAS ARE LIKELY TO BUILD TO 6 FEET LATE TUESDAY NIGHT...BUT WILL HOLD OFF ONE MORE CYCLE BEFORE ISSUING A SMALL CRAFT ADVISORY. LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... AS OF 345 PM MON...THE GRADIENT BETWEEN HIGH PRESSURE OFFSHORE AND A SHARPENING TROUGH/APPROACHING COLD FRONT WILL LEAD TO MODERATE SOUTHWEST WINDS TUE NIGHT THROUGH WED. SW WINDS WILL INC TO AROUND 20 KT GUSTING TO ~25 KT TUE NIGHT AS MODELS IN GOOD AGREEMENT ON MARGINAL SCA CONDITIONS DEVELOPING WITH SEAS INC TO AROUND 6 FT CENTRAL AND SOUTHERN WATERS. WINDS WILL TURN A NORTH TO NORTHEASTERLY DIRECTION OVER THE NORTHERN WATERS BY WEDNESDAY NIGHT AND THEN ALL WATERS BY THURSDAY AS THE FRONTAL BOUNDARY PUSHES OFFSHORE. WINDS WILL BE LIGHT...10 KNOTS OR SO..AS THE FRONT REMAINS OFFSHORE THURS. THERE IS SOME UNCERTAINTY WITH WIND DIRECTION FRI...AS SOME GUIDANCE INDICATES A RETURN TO SOUTH WINDS AS EARLY AS FRI MORNING. WILL MAINTAIN A MORE EASTERLY TREND FOR WINDS FRI. SEAS SUBSIDE TO 2-4 FT THURS INTO FRI. LOCAL SWAN/NWPS AND 12Z WAVEWATCH GUIDANCE IN GOOD AGREEMENT THROUGH THE LONG TERM. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...NONE. MARINE...NONE. && $$ SYNOPSIS...CTC NEAR TERM...CTC SHORT TERM...CTC LONG TERM...TL AVIATION...CTC/TL MARINE...CTC/TL
Posted on: Mon, 14 Jul 2014 19:51:32 +0000
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