Area Forecast Discussion
Issued by NWS Wilmington, NC

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000 FXUS62 KILM 200837 AFDILM Area Forecast Discussion National Weather Service Wilmington NC 437 AM EDT Fri Apr 20 2018 .SYNOPSIS... Temperatures will run 5 to 10 degrees below normal today thru Sunday as Canadian high pressure ridges across the area from the Great Lakes. Winds will be noticeably lower when compared to the past few days. The high will give way to low pressure moving out from the Gulf Coast states late Sunday. This low accompanied by beneficial stratiform rains, will slowly push across the region Monday thru Tuesday of next week, and possibly could persist into Wednesday of next week. && .NEAR TERM /THROUGH TONIGHT/... As of 330 AM Friday...Very quiet weather will prevail through the near term period as surface high pressure builds in from the northwest. With a very dry atmospheric column, even clouds will be at a premium. Highs today should be in the lower to middle 60s as guidance has been stable at these values. Lows Saturday morning, will be in the lower 40s along the coast with some upper 30s northwest and in the colder locations as ideal radiational conditions will be in place. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... As of 330 AM Friday...The forecast area will lie between 2 "bowling balls", ie. between 2 upper closed lows at the start of this period. The 1 affecting Maine and southeast Canada, will progress further away from the U.S. during this period. However, the other closed low will be able to progress, moving slowly eastward across the Gulf Coast States this weekend, and reaching the ILM doorsteps by Mon morning. At the sfc, models in decent agreement with Canadian High pressure ridging across the area from the Great Lakes during this weekend, with the high re-centering itself over the NE States at the end of this period. This will result in cool NE to ENE winds thruout this period which will help keep temperatures at 5 to 10 degrees below normal for both maxes and mins with the exception of Sunday night/Monday morning lows which will be near normal due to the modification of the air mass as well as onshore winds that may have a SE component by the end of this period. Clouds Sat thru Sun will be in the form of thin Cirrus Sat and becoming more opaque during the day on Sun. For late Sun thru Sun night, mid-level altostratus will become dominant with low level stratus across the far S to SW portions of the FA as the upper low approaches along with the threat for stratiform rains. && .LONG TERM /MONDAY THROUGH THURSDAY/... As of 300 PM Thursday...Very large high, more typical of the cool season, to be moving off the coast on Sunday. Meanwhile a cutoff upper low (also normally a cool season feature) to be crossing the Gulf States, leading to cyclogenesis. As often the case with a cutoff, the timing is often uncertain and too fast in guidance. Much of the cloudiness and rain expected to overspread the area Sunday night into Monday may now be about 12 hours slower. Another change from this time yesterday is that guidance is now suppressing the highest rainfall amounts to our south. Given the strength of the high to our north this seems plausible. Even so, the system will be slow moving and keep rain in the forecast through at least Wednesday. && .AVIATION /08Z FRIDAY THROUGH TUESDAY/... As of 06Z...VFR conditions are expected through the period as high pressure builds into the area. Gusty north winds are beginning to tamp down especially inland and should be of little concern for the remainder of the period. Extended outlook...VFR. Periods of MVFR/RA Monday/Tuesday. && .MARINE... NEAR TERM /THROUGH FRIDAY/... As of 330 AM Friday...Winds still blowing from the north at a fairly brisk rate of 20-25 knots across the waters this morning. However much lighter winds are just upstream and should move across the waters later this morning. As winds fall down below small craft criteria, the seas, which are hovering just above the six foot threshold will drop as well. Overall a modest northeast flow of 10- 15 knots will develop late morning and persist through most of tonight possibly increasing again very late. Seas will drop to 3-5 feet this morning as well and further to 1-3 feet by early Saturday. SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/... As of 330 AM Friday...The area waters will remain within a semi-tightened sfc pg Sat that will likely further tighten Sun into Sun night. This due to the closed low approaching the FA from the Gulf Coast States. Have ramped up ENE to E winds late Sun thru Sun night and have them approaching SCA thresholds by Mon daybreak along with building seas likely breaching the 6 foot plateau Mon morning. Significant seas will primarily be a function of wind driven waves that could be considered a pseudo ground swell as progged periods increase to 5 to 7 seconds. LONG TERM /SUNDAY THROUGH TUESDAY/... As of 300 PM Thursday...Onshore flow on Sunday the result of a very large area of high pressure moving eastward but remaining centered well north of the area. At the same time low pressure will be developing over the Gulf States. This setup will increasingly squeeze the gradient to where wind and seas both reach advisory levels. Both entities will be very slow moving, keeping advisory flags flying for the remainder of the period. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...None. NC...None. MARINE...Small Craft Advisory until 9 AM EDT this morning for AMZ250- 252-254-256. && $$ SYNOPSIS...DCH NEAR TERM...SHK SHORT TERM...DCH LONG TERM...III AVIATION...SHK

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