Area Forecast Discussion
Issued by NWS Wilmington, NC

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000 FXUS62 KILM 051547 AFDILM Area Forecast Discussion National Weather Service Wilmington NC Issued by National Weather Service Charleston SC 1047 AM EST Mon Dec 5 2016 .SYNOPSIS... Rain chances will decrease through the day as weak low pressure moves away from the coast. A stronger system will move back into the region tonight through Tuesday bringing more substantial rainfall. Quiet and seasonable weather will occur mid-week ahead of an arctic front which will cross offshore late Thursday. Very cold temperatures will follow for Friday and into the weekend. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Frontal wave is now located well to the northeast of Cape Hatteras and will continue to pull away from the region. Some lingering post-frontal isentropic assent is supporting scattered showers along the coast, but this activity will diminish over the next few hours. Temperatures have been held down this morning by diabatic processes, but should recover some this afternoon as rain ends. Opted to nudged highs down a few degrees to account for current trends and the latest high resolution temperature guidance. Visible satellite shows breaks in the cloud canopy moving across the northwestern tier from roughly Darlington, SC to Elizabethtown, NC. This should be temporary as clouds are expected to increase again later this afternoon as weak isentropic assent redevelops. Sky grids have been updated to reflect this thinking. && .SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/... As of 415 AM Monday...The potent mid-level s/w trof, over the lower to mid Mississippi Valley and associated sfc low, will lift to the NE reaching the Ohio River Valley by Tue afternoon. The associated sfc low will fill in, with a new low pressure system taking shape off the Southeast NC Coast. Ie. The Miller Type B Scenario. An occluded front will exist between the 2 sfc lows, that will dissipate as the coastal low becomes the dominate low. Meanwhile, wedge of high pressure across the area will remain strong due to the parent center of the sfc high remaining over the NE states well into Tue afternoon. This will result in a continued influx of cool air at the sfc with ILM inland areas remaining on the cool side. Once again, the front offshore will get pulled north as a warm front, and likely straddle along the immediate coast. Will have a nice range of temps depending how far inland the warmer temps push. At this point, it could be a repeat of what occurred on Monday or to a lesser degree since the source of cool air to sustain the wedge will be stronger. The better dynamics aloft with this system as a whole, will aid in the possibility of isolated thunder in the vicinity of the coastal front. Instability either at the sfc or elevated will be enough for possible mention of isolated thunder. Overall, looking at categorical overrunning rains early Tue morning thru early afternoon, ending from SW to NE. QPF will be equal or slightly hier than what occurs during Monday. The heaviest pcpn ends during Tuesday afternoon. A lagging mid- level weak s/w trof could ignite -shra Tues evening and for that left a chance POP. For Wed and Wed night, flow aloft no longer taps the Gulf as WSW flow becomes the mainstay. Weak high pressure builds across the FA. RH Model time heights displays indicate decent drying aloft which will enable skies to become mostly clear for Wed thru Wed night. Temps for Wed will run at or slightly below normal with neutral advection. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... As of 300 AM Monday...Arctic front to cross the Carolinas Thursday, with very cold conditions following in its wake. Guidance has slightly increased its moisture associated with the FROPA, and will carry SCHC POP for northern zones late Thursday as a few showers are possible. Increased column saturation above 600mb suggests increased cloud cover, but very dry air beneath this will prevent much more than a brief shower or sprinkle with the FROPA. All precip will be of the liquid variety however, it will be too warm for any snowflakes this time around. However, it will certainly FEEL like winter beginning Thursday night and persisting through Saturday as temps plummet. 850mb temps have warmed slightly in new guidance as the core of the cold air deflects to our north, but still expect highs only in the 40s Fri/Sat with lows dropping well into the 20s Friday night. Additionally, gusty winds Friday will make apparent temps even colder than that. The Canadian high pressure bringing this cold air will shift offshore quickly late in the wknd allowing temps to recover to seasonable values Sunday. && .AVIATION /16Z MONDAY THROUGH FRIDAY/... As of 12Z...A mixture of MVFR/IFR through the morning hours with gradual improvement to VFR this afternoon. Expect conditions to deteriorate again to MVFR/IFR tonight through the end of the valid TAF period. Latest radar imagery depicts showers moving across the area this morning, tapering off already from west to east. Will continue with low cigs, VCSH and the potential for areas of fog through later this morning, with conditions expected to improve to VFR this afternoon. Into tonight, rain chances return with conditions anticipated to return to MVFR/IFR due to low cigs and areas of fog. Expect north- northwesterly winds becoming north-northeasterly winds through the TAF period, with sustained winds 5 to 10 kts and intermittent higher gusts possible. Extended Outlook...Periods of MVFR/IFR likely through Tuesday night due to rainfall and low cigs/reduced visibilities. MVFR developing on Wednesday, with VFR returning on Thursday. && .MARINE... NEAR TERM /THROUGH TONIGHT/... Buoy sea and wind reports indicate conditions have dropped below Small Craft Advisory thresholds. Seas are still around 5 ft at 41108, but will continue to drop. Can not completely rule out a few gusts to 25 kt east and northeast of Cape Fear for the next 1-2 hours, but do not think these will be frequent enough for flags. Winds and seas will increaes again tonight. SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... As of 415 AM Monday...SCA conditions may again be met across all waters during Tue into Tue night. Front offshore Monday Night, will get pulled back to the north, across the Coastal waters and possibly onshore during the 1st part of Tuesday. Low pressure is expected to develop off the southeast NC Coast Tue afternoon and track northeast away from the local waters by Tue evening. This will pull the front, now a cold front, back off the coast and offshore Tue evening. Weak high pressure ridge in late Tue night and prevail thru Wed night. Peak winds will occur during Tuesday, slowly abating Tue night and continuing this trend thruout Wednesday. Significant seas will also peak during Tue and mainly dominated by short period wind driven waves. Seas will likely quickly subside Tue night thru Wed due to the lack of any long period ground swell progged to affect the local waters. PCPN will be widespread on Tue with mainly light to moderate rains with embedded thunderstorms. A few of these embedded thunderstorms could mix down the progged stronger winds aloft that could yield a SMW or atleast Marine wx statements. Activity becomes isolated Tue night with drier air and no pcpn for Wed. LONG TERM /THURSDAY THROUGH FRIDAY/... As of 300 AM Monday...Strong cold front will cross the waters late Thursday producing SCA conditions into Friday. Winds ahead of this front will increase and slowly veer to the west, before shifting to the NW and becoming 20-25 kts, driving seas up to 4-6 ft despite the offshore winds. These winds will remain strong through Friday, falling only slowly to 15-20 kts while becoming more northerly Friday night. Wave heights will fall quickly however as the offshore winds weaken, becoming 2-4 ft late. An SCA will likely be needed for late Thursday and a good portion of Friday. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...None. NC...None. MARINE...None. && $$ is the U.S. government's official web portal to all federal, state and local government web resources and services.