Area Forecast Discussion
Issued by NWS Wilmington, NC

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299 FXUS62 KILM 050526 AFDILM Area Forecast Discussion National Weather Service Wilmington NC 1226 AM EST Mon Dec 5 2016 .SYNOPSIS... Low pressure moving up the coast will bring light rain tonight. After a break on Monday a stronger system will affect the region Monday night into Tuesday leading to a more substantial rainfall. Quiet and seasonable mid week weather will be followed by Arctic air arriving Thursday night. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... As of 900 PM Sunday...Dense mid and high clouds have been traversing the Carolinas for 24 hours now courtesy of a powerful subtropical jet being steered by upper level low pressure over northern Mexico. Patchy light rain has been falling on and off all day from these clouds with totals less than 0.10 in most locations so far. This should change tonight as a warm front developing along the coast swings northward tonight. Deep isentropic lift developing west of this boundary should lead to fairly widespread rain tonight. Temperatures have been stuck in the 40s and lower 50s all day. While inland temperatures should hardly budge overnight, along the immediate coast look for temperatures to rise by 5-10 degrees overnight with the approach of the warm front. Low pressure developing almost overhead after midnight should drag the front back offshore before daybreak Monday. && .SHORT TERM /6 AM THIS MORNING THROUGH TUESDAY NIGHT/... As of 300 PM Sunday...Surface low pressure zipping away from the NC coast Monday morning will have pushed the front a good 150-200 miles south of the area by Monday afternoon. With the loss of isentropic lift there should actually be some breaks in the clouds Monday with rain chances dipping to only 10-20 percent by afternoon. Any lingering morning rain along the coast should wrap up really quickly with additional rainfall amounts less than a tenth of an inch after 7 AM. Highs Monday could approach 60 degrees, which is actually below normal but will feel wonderful after the dreary and cold Sunday we experienced. The big upper low over northern Mexico will finally eject out to the east Monday, leading to surface low pressure developing across the Deep South Monday night. Strengthening southerly flow ahead of this low should lift the stalled front northward again and bring it near the Carolina coast by daybreak Tuesday. Isentropic lift west of the front should again lead to widespread rain developing. With strong wind fields and advection of warm air northward, elevated instability should increase sufficiently that isolated thunderstorms will remain in the forecast for late Monday night into Tuesday. After the upper trough passes us by to the north Tuesday afternoon, precipitation should largely end with the front slowly sagging back offshore Tuesday night. Two interesting features in this forecast I wanted to mention: one is that the synoptic situation is actually favorable for a possible gravity wave event Tuesday. (a very stable surface airmass west of the front with unstable conditions aloft) Should a gravity wave develop across Georgia or South Carolina it would move eastward, persisting until it reaches the surface front at which point it should dissipate. Typically these waves produce wind gusts of 25-35 mph as they trickle along the back edge of a precipitation shield. Also, with nothing to scour out the low level moisture Tuesday and such low sun angles this time of year, stratus Monday night could lower into a widespread area of fog Tuesday which might persist much of the day west of the front. This could include the Pee Dee area plus Lumberton, Whiteville and Elizabethtown. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 3 PM Sunday...Fairly seasonable temperatures expected Wednesday and Thursday as a weak low level thermal ridge develops ahead of the impending Arctic front. Mid level flow will be out of the WSW and not favorable for deep moisture through the column. The boundary itself will thus likely move through rain-free but the change in airmass will be starkly noticeable by Friday as highs struggle their way into the mid 40s. Not much recovery is expected Saturday after a downright cold night Friday night featuring lows in the mid 20s. Saturday arguable may not feel as cold however as the wind stays light due to the high building overhead. As the high continues eastward Saturday night into Sunday some slow moderation will get underway. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... As of 06Z...Rain showers continuing to move SW to NE across the area, and this persistent light rain will lead to widespread IFR tonight. The rain will remain mostly light, so vsbys are expected to be primarily MVFR, but brief IFR in heavier rain is possible. More likely, the IFR will be experienced in lowering CIGS, possibly falling to LIFR towards dawn and early on Monday. Winds will be highly variable due to a coastal front, with southerly winds developing at ILM/CRE/MYR and N/NE winds continuing inland. Drying will occur during the day Monday with slow improvement to VFR during the aftn as 10kt NW winds clear the cigs and rainfall. This improvement will be short lived however, as a more significant round of rainfall is expected to begin Monday night, with MVFR and IFR returning to the terminals. Extended Outlook...IFR/rain likely Mon night through Tuesday night. MVFR becoming VFR Wednesday and extending into Thursday. Slight chance MVFR/showers Thurs night into early Fri. && .MARINE... NEAR TERM /THROUGH TONIGHT/... As of 900 PM Sunday...Northeast winds should turn southerly after midnight. Low pressure developing overhead will push the boundary back offshore with northwesterly winds developing by daybreak Monday. Unfortunately for mariners, the approach of this system will lead to increasing winds and seas overnight, and it appears we should experience a period of 15-25 kt winds and 3-6 foot seas late tonight into Monday morning. SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... As of 300 PM Sunday...Low pressure moving out to sea late tonight will push the front 150-200 miles south of the area for Monday. North to northeast winds are expected much of Monday and Monday evening as a result. However the approach of low pressure from the Deep South will begin to tug this front northward again late Monday night, and the boundary is expected to sweep back across the waters as a warm front around daybreak Tuesday. This should allow wind directions to veer southerly again with another increase wind wind speeds to 15-25 kt. LONG TERM /WEDNESDAY THROUGH FRIDAY/... As OF 3 PM Sunday...Wednesday will offer up a weak pressure gradient and thus fairly tame winds. Seas will still be slightly agitated from the short term storm system, though well below any advisory or headline levels. Winds ramp up Thursday as the Arctic front approaches. This boundary looks to arrive a bit sooner than previously thought and may blast across the waters during the afternoon or evening. Small craft advisory may be needed Thursday night and/or Friday. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...None. NC...None. MARINE...Small Craft Advisory until 10 AM EST this morning for AMZ250- 252-254-256. && $$ SYNOPSIS...MBB NEAR TERM...TRA SHORT TERM...TRA LONG TERM...MBB AVIATION...JDW MARINE... is the U.S. government's official web portal to all federal, state and local government web resources and services.