Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 091939 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 240 PM EST Fri Dec 9 2016 .SYNOPSIS... Arctic high pressure will build across the area through Saturday. A cold front will approach from the west late Sunday and move through the area on Monday. && .NEAR TERM /THROUGH TONIGHT/... As of 240 PM Friday... A chilly day (temps around 12-15 deg below normal) will become a chilly night, as arctic high pressure continues to build into the area from the NW. Passage of a weak sheared wave just to our north will bring a few high clouds mainly to the northern forecast area overnight (some of this cloudiness could be orographically enhanced late). But otherwise skies will be generally clear tonight, and this in combination with light surface winds will foster good radiational cooling, with thicknesses likely to be a bit lower than they were this morning. Expect temps to bottom out in the 18-24 degree range, with the cooler readings in outlying areas of the northern/western Piedmont. -GIH && .SHORT TERM /SATURDAY AND SATURDAY NIGHT/... As of 200 AM Friday... Flow aloft transitions to zonal on Saturday. Otherwise, very little little change as the modified arctic high pressure migrates east atop the region. Temperatures Saturday and Saturday night will be very similar to today and tonight. Highs 40 to 45. Lows 20 to 25. && .LONG TERM /SUNDAY THROUGH THURSDAY/... As of 400 AM Friday... Overview: Long range model guidance has come into better agreement on Sunday/Monday, however, considerable uncertainty plagues the remainder of the extended forecast. Sun/Mon: A shortwave trough and attendant low pressure system expected to move onshore the Pacific NW on Saturday is progged to track rapidly east across the Upper Midwest (Sun), Great Lakes (Sun night), and New England (Mon) via a 125-150 knot upper level jet extending from coast-to-coast at ~40 degrees latitude. An associated cold front will rapidly approach the mountains from the west Sunday night, however, the front will slow down as it tracks SE through the Carolinas on Monday and will likely stall in a west-east orientation over the Deep South/Southeast Tuesday morning. With the above in mind, expect increasing cloud cover and highs in the 40s on Sunday (coolest NW/warmest SE), with light rain assoc/w southerly return flow /warm advection/ possible Sunday evening/night, primarily in the SE coastal plain. Chances for precipitation will increase on Monday as the front progresses into the Carolinas. Temperatures on Monday will be a function of strong warm advection, cloud cover, and precipitation, resulting in low confidence. At this time will indicate highs ranging from the mid 50s NW to mid/upper 60s SE. Mon Night-Thu: Considerable uncertainty persists from Monday night onward as the aforementioned front stalls in a west-east orientation across the Deep South/Southeast, beneath an energetic upper level pattern characterized by numerous small amplitude waves embedded within a ~150 knot jet that extends from the Pacific to the Atlantic. With confidence so low, will make little change to this period of the forecast. -Vincent && .AVIATION /18Z Friday through Wednesday/... As of 120 PM FRIDAY... High confidence in chilly but tranquil aviation conditions for the next 24 hours. Skies will be virtually cloud-free with unrestricted vsbys for the rest of today through tonight and into Saturday as high pressure builds in from the NW. Only a few high clouds tonight are expected as a weak mid level wave passes by within a fast flow aloft. Looking beyond 18z Saturday, VFR conditions should hold through the first half of Sunday as high pressure builds overhead. As a warm front approaches from the south, moisture will increase, and cigs will trend to MVFR then IFR Sunday afternoon from south to north. There is a good chance of low level wind shear conditions Sun night into Mon morning with 35-40 kt winds from the SW at 1500-1800 ft AGL. Adverse aviation conditions, including sub-VFR cigs and vsbys, are expected to dominate from late Sunday through at least Monday night -- and perhaps into Wednesday -- as waves of low pressure track along the frontal zone as it holds over or just south of the area. -GIH && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...CBL NEAR TERM...Hartfield SHORT TERM...CBL LONG TERM...Vincent AVIATION...Hartfield is the U.S. government's official web portal to all federal, state and local government web resources and services.