Area Forecast Discussion
Issued by NWS Wilmington, NC

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401 FXUS62 KILM 171054 AFDILM Area Forecast Discussion National Weather Service Wilmington NC 555 AM EST Sun Dec 17 2017 .SYNOPSIS... Today will see a slow increase of clouds from the southwest with weak high pressure prevailing into tonight. Temperatures today will be seasonable. A frontal system oriented east to west will stall just south of the forecast area by Monday and persist thru the mid-week period. Low pressure will develop on the stalled boundary and push off the SC Coast late Wed and offshore Thursday. Rain chances will be low Monday into Tuesday then increase due to the low`s passage during Wednesday. High pressure will return and ridge across the area from the NE States during the late week period. Temperatures will be above normal during the upcoming work week and at times well above normal. && .NEAR TERM /THROUGH TONIGHT/... As of 330 AM Sunday...A broad west to southwest flow will develop across the region through the near term period. At the surface high pressure will drift further offshore and a diffuse surface pattern will develop across the eastern carolinas. Plenty of cloud cover in the form of mid level moisture will drift across the area later today from a weakening system moving across the Tennessee Valley. The GFS as does the HRRR actually develops a little light rain across northern areas late today as whats left of this system races across. I did not add pops at this point as the surface dryness will be tough to overcome but it needs to be monitored. As for temperatures, off to another cold start and opted to undercut guidance based on the anticipated cloud cover and MOS`s performance Saturday. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... As of 330 AM Sunday...Split jetstream flow this period with the southern branch mainly pushing across the FA this period keeping any cold outbreaks well north of the local area. Ridging aloft will extend across the SE States with weak sfc high prevailing. A stalled east to west oriented frontal boundary will materialize just south of the FA during this period. Along and north of this front will see cloudiness with a low chance for light rainshowers. Modest to good chance POPS will occur later Tue into Wed as a mid-level s/w trof and associated sfc low ejects out of the Desert SW and tracks along the Gulf Coast States, reaching the Alabama and Georgia border by Wed morning. Temperatures this period will run 10 to as much as 15 degrees above normal. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... As of 300 PM Saturday...Moisture poised to advect into the area on Tuesday, perhaps rapidly, ahead of a decelerating front that may stall over the region. The GFS is quickest with the moisture advection and is likely too fast. Will ramp POPS more in accordance with slower guidance like the EC and Canadian, both implying a Tuesday night into Wednesday rain event. The rain seems to shut off on Thursday as low pressure developing off Hatteras helps to push the boundary to our south. There may not be much to scour out cloud cover while we are in this wedge- like setup. Moisture will then further increase in a prefrontal southwesterly flow regime on Friday. This front may arrive on Saturday, with rain chances seemingly limited to FROPA and not so much ahead of it. && .AVIATION /12Z SUNDAY THROUGH THURSDAY/...
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As of 12Z...Weak low pressure will approach the region this evening. Look for light southerly flow this morning. Mid and high clouds will arrive this afternoon with rising dewpoints. Cloudy skies are expected through the overnight hours, worst case MVFR ceilings and visibilities after midnight. Extended Outlook... Unsettled weather Monday through Thursday morning as a near stationary front moves in and out of the region.
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&& .MARINE... NEAR TERM /THROUGH SUNDAY/... As of 330 AM Sunday...Very light wind fields and seas will continue through the period across the coastal waters. As high pressure drifts east, a weak pressure pattern persists. This lends itself to erratic wind directions and the forecast will show north, west, and southwest winds represented, all ten knots or below. Significant seas will remain benign as well with 1-3 feet and probably more like 1-2 feet. SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... As of 330 AM Sunday...Weak high pressure early Mon will give way to a stalled east to west oriented frontal boundary extending inland near Cape Romain. Winds will generally be westerly at 10 kt Monday and increasing to 10 to 15 kt Tue with gusts up to 20 kt Tue night as the sfc pg tightens in advance of low pressure along the stalled front approaching from the west. Could see isolated showers Mon into Tue increasing in coverage late Tue thru Tue night. Significant seas will hover around 2 ft Mon into Tue with 2 to 3 ft Tue night except up to 4 ft for the waters south of Cape Fear to Little River Inlet due to a longer fetch with westerly wind directions. An easterly 1+ foot ground swell at 9 to 10 second periods will dominate Mon. Westerly wind driven waves at 3 to 5 second periods will become dominate Tue into Tue night. LONG TERM /WEDNESDAY THROUGH THURSDAY/... As of 300 PM Tuesday...Westerly wind on Tuesday as high pressure roosts in the Bahamas and Florida peninsula. A cold front will drop into the waters and likely stall Tuesday night as a wave of low pressure develops to our west. This low remains fairly flat as the boundary sinks to our south on Wednesday allowing a NE wind to spread southward across the waters. Northerly winds will veer as Thursday progresses as the day initially starts with a wedge of high pressure that weakens later in the day. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...None. NC...None. MARINE...None. && $$ SYNOPSIS...DCH NEAR TERM...SHK SHORT TERM...DCH LONG TERM...MBB AVIATION...43 MARINE...

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