Area Forecast Discussion
Issued by NWS Wilmington, NC

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000 FXUS62 KILM 210714 AFDILM Area Forecast Discussion National Weather Service Wilmington NC 314 AM EDT Fri Apr 21 2017 .SYNOPSIS... Bermuda High pressure will extend west across the region through early Sunday. A backdoor cold front is expected to stall north of the area during the weekend. Strong low pressure will move slowly through the Carolinas Sunday and Sunday night and then offshore Monday. Widespread rainfall is expected along with the possibility of strong to severe thunderstorms. This system will then move slowly away from the area as high pressure and dry weather builds in for the middle and later portions of next week. && .NEAR TERM /THROUGH TONIGHT/... As of 300 AM Friday...Bermuda High and mid level ridge remain in place today and tonight with cold front lingering northwest of the area. Front tries to move into central NC later tonight but will have limited success doing so. Conditions today will be driven by features more typical in summer, the Bermuda High and a sea breeze. Gradient will be a little better defined than it was on Thu which may lead to more of a southerly resultant sea breeze. Moisture will be limited this afternoon and evening, even moreso than Thu afternoon, and this is likely to limit convection, even on the sea breeze. Best chance for storm development will be at the sea breeze inflection point, but even here do not feel pop above 10% is warranted. Should a shower develop it will be very short lived. Conditions today will be on the breezy side with southwest flow in excess of 15 mph at times. Temperatures will continue to run well above climo with areas away from the beaches rising into the upper 80s. Isolated 90 degree readings cannot be ruled out. Lows will continue above climo as well with temperatures in the mid to upper 60s. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... As of 300 AM Friday...Warm ridge will get suppressed to our S and E Sat as a cold front struggles to backdoor through North Carolina. This front still looks as though it will get hung up N of our Forecast Area during the first half of the weekend. Upper low across the mid south Sun morning is now expected to take a southeast track and on this path will move across the southern Appalachians late Sun night and Mon morning. The surface low will move slowly across the Carolinas Sun and Sun night and should be moving offshore of the Carolinas Mon morning. Forcing is weak Sat, and moisture is shallow. Mixed layer CAPE values do climb to or just above 500 J/kg and so isolated showers and thunderstorms will be possible with the highest POPs from LBT to Burgaw, in closest proximity to the frontal zone. Attention then turns to system to our W and this promises to be a wetter scenario for the eastern Carolinas with strong lift developing later Sun and Sun night. Precipitable water values will climb to more than one and a quarter inches as the depth of moisture deepens. Mixed layer CAPE values are expected to reach 500 to 1000 J/kg. Thus, the area will have all of the necessary ingredients for showers and thunderstorms. Will show POPs increasing to categorical. At this time, rainfall amounts of one half to one and a half inches seems attainable. There still is some risk for strong to severe thunderstorms and the track of the surface low will be important in determining where this risk will be highest. Bulk shear values and winds within 5 kft of the surface are quite marginal and do not support widespread severe weather. Model consensus would suggest the risk for severe weather will be higher across our southern counties and points S. Temps will be well above normal, warmest Sat and coolest Sun night. && .LONG TERM /MONDAY THROUGH THURSDAY/... As of 300 PM Thursday...The sfc low center should be just over or near the Cape Fear coast Mon morning, but the deep upper level trough will still be west. The cutoff low center will track mainly south of the area but the trough will extend up through the Carolinas. The low will move east through the day on Mon and then will travel slowly N to NE parallel to the coast. This will keep clouds and rain chances in the forecast possibly through Tues. Should see drier conditions by mid week as weak high pressure builds in behind departing low. Temps should be a good 10 degrees cooler on Monday in northerly flow on the back end of the low. Clouds and rain will keep smaller diurnal ranges with temps heading back toward normal Tues into Wed as low slowly departs. Overnight lows will probably be 55 to 60 most places. Temps should be back up into the 80s by mid week with increasing sunshine. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... As of 06Z...High confidence in VFR conditions through the period. Boundary layer winds will remain 5 to 10 kt overnight due to 20 to 30 kt low level nocturnal jet. This will prevent development of significant fog and the low levels are dry enough that stratus is not a concern. Southwest flow will be on the breezy side today with potential for gusts in excess of 20 kt, especially along the coast. Cannot rule out an isolated afternoon shower but the chance a terminal would be impacted is very low. Any diurnal clouds that develop will dissipate around sundown. Extended outlook...MVFR/IFR conditions possible in showers and TSTMS, mainly Sun through Mon. Otherwise VFR. && .MARINE... NEAR TERM /THROUGH TONIGHT/... As of 300 AM Friday...Bermuda High will be the dominant surface feature through the period. The sea breeze and a cold front sitting well northwest of the area will tighten the gradient somewhat today, increasing southwest flow to 15 to 20 kt by midday. Southwest flow will remain close to 20 kt into the evening and overnight. Seas currently 2 to 3 ft build to a solid 3 ft this afternoon and 3 to 4 ft overnight. SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... As of 300 AM Friday...Ridge of high pressure will be offshore at the start of the period. A cold front to our N will be strung out W to E and will struggle to make southward progress. This front is expected to stall out before reaching any of our waters Sat night. A strong area of low pressure and its associated frontal system will approach from the W Sun and move slowly across the waters Sun night into Mon, bringing widespread convection. SW winds will persist Sat into Sun. These winds will be strongest Sat afternoon and Sat night, sustained at 15 to 20 kt. Winds will back slightly on Sun, SSW to S. Late Sun night and Mon morning, the wind direction will back all the way around to NE. Seas will build up to 3 to 5 ft through Sat night with seas holding near this range through Sun night before building further Mon. LONG TERM /MONDAY THROUGH TUESDAY/... As of 300 PM Thursday...Low pressure will be moving across the waters Mon with a sharp shift in wind direction to the N on the back end. The center of the low should be just near or south of the Cape Fear coast Mon morning. The winds may diminish and become quite variable at this time before the low slowly moves east and north through late Mon into Tues. This should allow seas to diminish for a brief period Mon morning before a sharp rise in northerly surge on the back end. Winds may increase up to 15 to 25 kt Mon into Mon night before diminishing through late Tue as the low tracks farther away. Seas may remain above SCA late Mon into Tue, diminishing Tue night in a lighter northerly flow. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...None. NC...None. MARINE...None. && $$ NEAR TERM...III SHORT TERM...RJD LONG TERM...RGZ AVIATION...III is the U.S. government's official web portal to all federal, state and local government web resources and services.