Area Forecast Discussion
Issued by NWS Wilmington, NC

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000 FXUS62 KILM 231027 AFDILM Area Forecast Discussion National Weather Service Wilmington NC 422 AM EDT Fri Mar 23 2018 .SYNOPSIS... High pressure will build in across the area through early Saturday. A quick moving system will move across the area late Saturday and Sunday. Strong High pressure will build in from the northeast for much of next week before a warming trend finally begins late in the period. && .NEAR TERM /THROUGH TONIGHT/... As of 330 AM Friday...Freeze Warning will be allowed to continue and will expire at 9 am. Will send out an updated NPW shortly. No pcpn expected this period but clouds will increase from the NW to SE, starting out with High-level Cirrus and eventually Mid-level Altocu or High Stratocu late tonight. The FA will remain under the spell of a longwave upper trof, with it`s north to south axis remaining off the Carolinas Coasts. Models do indicate a progression of the longwave pattern eastward with an upper ridge on the doorsteps from the west. The mentioned clouds are from a mid-level s/w trof that undermines the upper ridge and more or less gets swallowed up by the dry air associated with the upper ridge. As for max/min temps, the FA should see 55 to 60 for todays highs, and 35 to 40 for tonights lows. The possibility for a widespread freeze has diminished for Saturday morning. However, Frost Advisory conditions are possible which will roughly depend on low sfc dewpoint depressions and winds near calm and negligible clouds. The best location for this to occur will be the NE portions of the ILM CWA, away from the immediate coast. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
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As of 300 AM Friday...An unsettled Saturday will transition to a clearing but cold Sunday as this winter-like pattern continues. Deep eastern CONUS trough will gradually shift its axis to the east this weekend, but will then be reinforced by a shortwave digging through the upper MS VLY early on Saturday and then racing SE to become off the North Carolina coast Sunday morning. As this occurs, a weak wave of low pressure will develop as the surface reflection of this feature, which will then move along a wavering front stalled near the southern CWA border. In this setup, moisture will steadily increase within the atmospheric column due to a combination of moist advection, isentropic lift, and increasing frontogenesis, the latter two will combine with at least weak PVA to drive rainfall across the CWA late Saturday through early Sunday. Forecast profiles show PWATs climbing towards 1.25 inches coincident with peak isentropic lift near the 300K surface and some pinched isotherms/enhanced frontogenesis in the 850-700mb layer. Although the heaviest rainfall is expected to be just north of the area, widespread stratiform will have the potential to produce 0.25 to 0.50 inches of rainfall, and will ramp POP up to categorical north zones, high chance south. Rainfall will come to and end as the weak low pushes away Sunday morning and forcing weakens as high pressure wedge builds down the coast. This will bring a drying of the column, but low-level moisture will become trapped within the subsidence inversion as is typical in these wedge setups. Do not expect much sunshine on Sunday despite decreasing showers, and guidance is likely too warm despite showing highs only in the low 50s. Highs Sunday may climb only into the upper 40s far north zones, low 50s to the south, which will be only a few degrees cooler than the still cold mid to upper 50s forecast for Saturday. Mins Saturday night will be near seasonable norms, low to mid 40s, but will drop toward the upper 30s Sunday night. Depending on how quickly moisture can scour out Sunday night, some frost will be possible as temps crash into Monday morning, but attm expect mins will be just warm enough and cloud cover dense enough, to prevent any frost locally.
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&& .LONG TERM /MONDAY THROUGH THURSDAY/... As of 3 PM THURSDAY...The extended period will feature considerable amplitude at the mid levels with an omega blocking pattern across the conus for a few days. This will keep the period mostly dry with modifying temperatures. Initially however, a cold front will be settling south embedded within yet another deep trough across the northeast. Some isentropic lift may provide a few cool rain showers Sunday but that`s about if for the period regarding pops. The entrenched surface high will take some time to modify and this is reflected in the temperature forecast/grids. HIghs will be stuck in the 50s Sunday and Monday warming to the 70s by Thursday which is much closer to normal. Overnight lows will follow the same trend with middle to upper 30s MOnday and Tuesday morning warming to the 50s by the end of the period. && .AVIATION /08Z FRIDAY THROUGH TUESDAY/... As of 06Z...High confidence of VFR conditions for the next 24 hrs. Look for skc conditions this morning give way to a cirrus deck that will be trucking from NW to SE at a good clip. Could see a bkn low AC cloud deck, ie. 6 kft, late this afternoon or evening. The problem child today will be the winds. The mornings weak sfc based inversion will break mid to late morning allowing NW winds aloft to mix down to the sfc. Thruout the afternoon looking at speeds of 10 to 15 kt with gusts to 20 kt. By and after sunset, winds will back down considerably. Could see patchy ground fog develop toward 06z tonight. Extended outlook...VFR Fri/Sat. MVFR/IFR/Rain developing Saturday night and persisting into Sunday. VFR Mon/Tue. && .MARINE... NEAR TERM /THROUGH TONIGHT/... As of 330 AM Friday...The local waters will likely see it`s best conditions to venture out into the Atlantic today and possibly most of Saturday before winds and seas pick up. Looking at mainly offshore winds this period, running 10 to 15 kt nearshore waters, and 15 to 20 kt across the outer waters. Significant seas will follow suit with range from 1 to 2 ft nearshore waters and 3 to occasionally 4 ft outerwaters. Winds and resultant seas with common periods of 3 to 5 seconds, will both diminish and subside-some tonight and heading into daylight Saturday. This will probably be as good as it gets considering whats on the doorsteps after this period. SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... As of 300 AM Friday...A fluctuating boundary will create variable wind directions Saturday, but this front will sink southward followed by gusty NE winds and SCA conditions on Sunday. As the front moves in the vicinity of the waters Saturday, winds will vary between NE at 10-15 kts NC waters, to SE 10-15 kts SC waters, but the exact position of the front will determine where these varying directions will occur. The front will get pulled southward as a wedge of high pressure builds south on Sunday, causing winds to become NE across all waters with speeds rising to 20-25 kts. This NE surge will push seas to 5-7 ft and an SCA is likely on Sunday, after wave heights climbing slowly from 1-3 ft to 2-4 ft on Saturday. LONG TERM /MONDAY THROUGH WEDNESDAY/... As of 3 PM THURSDAY...Surface high pressure anchored well to the northeast will be the primary player for the extended marine forecast. With a blocking pattern at the mid levels this feature will remain in place through most of the period weakening late. Winds from the northeast of 20-25 knots will be in place ON Monday. By later Tuesday winds diminish considerably. The prolonged higher winds will produce significant seas of 3-7 feet and a small craft advisory is a good bet based on both winds and seas for a good chunk of the period. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...Freeze Warning until 9 AM EDT this morning for SCZ017-023-024- 032-033-039-055-058-059. NC...Freeze Warning until 9 AM EDT this morning for NCZ087-096-099- 105-107-109. MARINE...None. && $$ SYNOPSIS...DCH NEAR TERM...DCH SHORT TERM...JDW LONG TERM...SHK AVIATION...DCH is the U.S. government's official web portal to all federal, state and local government web resources and services.