Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 082011 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 311 PM EST Thu Dec 8 2016 .SYNOPSIS... An arctic cold front will move through the area today. An expansive arctic high will dominate Friday through the weekend. && .NEAR TERM /THROUGH TONIGHT/... As of 1000 AM Thursday... A few returns on radar this morning are associated with mainly mid clouds and at best just a few drops of rain are possible across the eastern Piedmont and Coastal Plain. The previously stalled front over western NC is now moving east through central NC as an expansive arctic high build east in its wake, with northwest winds now observed to I-95. 850mb and 925mb analysis show cold advection underway, though it`s not terribly strong yet. The best 700mb moisture will push east of the area this morning, but south- southwest flow aloft will keep some high clouds over the area, so the combination of clouds and cold advection will hinder warming some, especially across the northwest half of the area. A blend of NAM and GFS temp guidance looks reasonable, with only 3-6 rises in most locations, resulting in highs of 49-57. Strong CAA will continue overnight as expansive Arctic high begins east into the region. Overnight lows in the mid 20s to upper 20s with a steady wind 7kt breeze resulting in chill values in the teens. && .SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/... As of 250 AM Thursday... The expansive arctic high pressure will dominate the eastern two- thirds of the country Friday and right on through the weekend. H8 temps crash to -10 Celsius Friday-Friday night, which is easily 2 to 3 standard deviations below normal, while low-level thicknesses bottoming out around 1275 meters. This will support temps a good 10 to 15 degrees below normal. Highs in the upper 30s to lower 40s. Lows in upper teens to lower 20s. && .LONG TERM /SATURDAY THROUGH THURSDAY/...
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As of 310 PM Thursday... The medium range models are in good agreement with the migration of ~1035 mb modified arctic high pressure across the Central Appalachians and Middle Atlantic states Sat and Sat night. Cold temperatures --10-15 degrees below average-- will result, with highs 40-45 and lows in the lower to middle 20s. Aside from cirrus, some of which may become briefly orographically-enhanced over the wrn Piedmont early Sat, the column will otherwise remain dry/clear. A Pacific shortwave trough, embedded within fast and broadly cyclonic flow across much of the Lower 48, will support a migratory wave of low pressure from the TX panhandle Sun to the Nrn Appalachians Mon. A preceding warm/coastal front will retreat Nwwd across central NC with an associated chance of showers during that time (Sun-Mon). Temperatures will moderate with the retreat of the warm front, and clouds. The trailing cold front, and continued chance of showers, will follow and cross NC late Mon-early Tue. Uncertainty in the mid to late week forecast remains above average. There are indications that a flat frontal wave will zip off the SE U.S. during the middle of the week; and this feature may spread a shield of light rain across NC late Tue-Wed. Thereafter, the models continue to indicate another cold frontal passage and associated arrival of colder temperatures will occur by Wed night-Thu, but recent model runs have backed off somewhat on how far S the next dome of arctic air will plunge.
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&& .AVIATION /18Z THURSDAY THROUGH TUESDAY/... As of 1245 PM THURSDAY... Winds are turning to northwest in the wake of a cold front crossing central NC today, with gusts to around 20kt likely to spread west to east as cold advection strengthens. Skies will clear through the evening hours as high clouds slowly shift east, and VFR conditions will continue. Some of the gusts could continue overnight, but for the most part guidance suggests winds will weaken to 6-10kt out of the northwest and then increase to 10-15kt gusting 15-20kt on Friday. Outlook: VFR conditions are expected through the weekend. There is a small chance of sub-VFR ceilings on Sunday, with better chances Monday and Thursday. && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Badgett NEAR TERM...CBL/Smith SHORT TERM...CBL LONG TERM...MWS AVIATION...Smith

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