Area Forecast Discussion
Issued by NWS Wilmington, NC

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000 FXUS62 KILM 231032 AFDILM Area Forecast Discussion National Weather Service Wilmington NC 533 AM EST Mon Jan 23 2017 .SYNOPSIS... Stacked low pressure system will move overhead today...and lift northeast to off the DELMARVA Coast by Tue daybreak, and to off Cape Cod by Tue evening. The area could see scattered showers later today along with an isolated rumble of thunder from midday thru this afternoon. High pressure from the south will ridge across the area Tue and Wed with temperatures running above normal. A cold front pushes across early Thursday followed by cooler high pressure for the end of the week becoming even colder during this upcoming weekend with daily temperatures dropping back to and below normal. && .NEAR TERM /THROUGH TONIGHT/... As of 330 AM Monday...Vertically stacked low pressure is currently centered over the western Carolinas early this morning. The vertically stacked low will slowly track to the eastern Carolinas by sunset today. The low will begin a jog to the NE tonight, reaching the DELMARVA Coast by daybreak Tue. The cold core low being overhead during the max heating of the day, will result in some decent lapse rates across the FA. The pcpn that develops today will convective in nature and would not be surprised if very small hail is produced given freezing levels dropping to 5k to 6k feet at their lowest this aftn and plenty of moisture avbl thru the atm column up to 5h also where the -20 degree C level is found this aftn. Overall instability remains in question for TSTORM action but cannot ignore the passage of a stacked upper low overhead during this time of the year. Stayed closer with the moisture profile of the GFS and kept POPS below 50 percent. Projected QPF will generally run less than one quarter of an inch. A cold front will push across later this aftn inland...early evening at the coast. This will end the pcpn threat with sfc winds veering from SW to W to NW. The sfc pg will tighten-some later tonight on the backside of the upper closed low lifting to the NE. This will keep winds active tonight and thus fog no longer being a problem. For temps, basically stayed slightly lower by a couple degrees after applying a consensus of MOs guidance. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... As of 400 AM Monday...The ILM CWA will remain under cyclonic flow during Tue associated with the Stacked Low moving from off the DELMARVA Coast Tue morning to Cape Cod by Tue evening. Models are in decent agreement late Tue thru Wed with a low amplitude mid level and sfc ridging extending north across the FA from Florida and the Bahamas. The atm column dries out nicely by the start of this period and continues into Wed evening. Thus, sky conditions will be conducive to Mostly Sunny and clear nights. The exception will be for late Wed night when a cold front approaches from the west. Have included an increase in clouds with low chance POPs for light showers during the pre-dawn hrs, mainly west of the I-95 corridor. For temps, stayed with a Mos Guidance Consensus. && .LONG TERM /THURSDAY THROUGH SUNDAY/... Previous forecast used... As of 3 PM Sunday...Upper level ridge axis moves offshore on Wednesday yielding deep layer SW to WSW flow. Expecting a mostly sunny and unseasonably warm afternoon. Cold front comes through late Wednesday night driven by very low amplitude and confluent upper system keeping rain chances minimal. Cold air advection Thursday is weak initially allowing for highs in the low to mid 60s early before temperatures possibly start a non- diurnal decline. The remainder of the period will bring cool and dry advection. The southern branch of the upper jet splits off and gets hung up as a positively tilted trough over the SWrn U.S. The northern branch will end up a broad and positively tilted trough over the Eastern U.S. Daytime highs will be stuck below climatology in the cold advection regime whereas breezy well-mixed nights will be seasonably cool. && .AVIATION /12Z MONDAY THROUGH FRIDAY/...
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As of 12Z...Deep moisture has exited, however the strong upper low still needs to come through this afternoon. There will be decent solar insolation, however given the sun angle, do not expect too much CAPE this afternoon, but enough to kick off some fairly vigorous showers around max heating. Given the cold air aloft, expect gusty winds with the showers. Most of the activity will end by late afternoon with VFR conditions expected tonight. Extended outlook...Expect mainly VFR. A dry CFP slated for early Thu.
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&& .MARINE... NEAR TERM /UNTIL 6 AM MONDAY MORNING/... As of 400 AM Monday...SCA for all waters thru Tue afternoon. Elevated winds and seas expected this period. Exception is when the center of the stacked low moves across the area during today. The sfc pg will relax enough for SW winds to temporarily drop below SCA thresholds. By late this aftn and early this evening, the stacked low will finally lift NE of the area allowing the passage of a sfc cold front. The sfc pg will re- tighten and result in WNW to NW winds increasing back to SCA thresholds, and continuing during the early Tue morning hrs. Significant seas will continue elevated and be dominated by wind driven waves at 5 to 7 second periods. Seas initially at 5 to 9 ft may temporary drop a few ft later today but then re-stabilize in the 4 to 8 ft range tonight as gusty WNW to NW winds take over. Low chance exists for showers to occur later today. SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/... As of 415 AM Monday...Cyclonic flow to continue thru Tue as the stacked low lifts further NE reaching Cape Cod by sunset Tue, much further away from the ILM Waters. Looking at a sfc pressure pattern and relaxing sfc pg with diminishing NW to W winds likely below SCA levels by or during the aftn. Weak ridging to extend northward from Florida and the Bahamas Tue night thru Wed, resulting in winds backing to the W to SW around 15 kt. Wed night, an approaching cold front from the west will result in the sfc pg tightening and SW winds back up to 15 to 20 kt. Significant seas will peak at the start of this period. An offshore wind trajectory Tue into Tue night will help subside the seas except for the waters from Cape Fear to Little River Inlet where a Westerly wind direction will have a longer fetch to produce slightly hier seas than surrounding zones. Seas will subside to 2 to 4 ft Tue night and hold in that general range thru Wed. Seas will begin to build Wed night ahead of an approaching cold front with increasing SW wind driven waves. LONG TERM /WEDNESDAY THROUGH FRIDAY/... Previous forecast used... As of 3 PM Sunday...Coast-parallel southwesterly flow on Wednesday ahead of a cold front. Though the winds will increase to the 15 to 20kt range any headline or advisory-worthy seas will remain outside of the 20nm forecast zone. With the approach of the boundary Wed night into Thursday we may add some gustiness and possibly introduce some 5 ft waves. A sharp late morning veer to NW Thursday will give way to abating wind speeds. Wave faces will steepen and a cautionary headline may be appropriate for a narrow span of time. A broad and weakening band of NW flow will be found across the eastern U.S on Friday. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...None. NC...None. MARINE...Small Craft Advisory until 6 PM EST Tuesday for AMZ250-252-254- 256. && $$ SYNOPSIS...DCH NEAR TERM...DCH SHORT TERM...DCH LONG TERM...MBB AVIATION...43 is the U.S. government's official web portal to all federal, state and local government web resources and services.