Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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121 FXUS62 KRAH 171436 AFDRAH AREA FORECAST DISCUSSION National Weather Service Raleigh NC 1030 AM EDT Tue Sep 17 2019 .SYNOPSIS... A backdoor cold front will move south across central NC this afternoon and evening. Canadian high pressure will build down the eastern seaboard into NC tonight through Friday bringing much cooler and less humid conditions. && .NEAR TERM /TODAY THROUGH TONIGHT/... As of 1032 AM Tuesday... Central NC will lie within the dry northerly flow aloft between the the upper trough off the NE US coast/Canadian maritimes and the flanking central US ridge. Visible satellite imagery this morning shows the back-door cold front making it`s way south through the DELMARVA with very little shower activity noted along the front. Given limited moisture transport and continued capping/warm air aloft, this trend is expected to continue as the front progresses south towards the area, with only a slight uptick in convective coverage thanks to favorable diurnal heating and resultant weak destabilization as the front approaches the NC-VA line during the late afternoon. Expect isolated to widely scattered showers across the north with little to nothing across the southern zones. Convection will diminish with loss of heating with the potential for some lingering post-frontal light rain/drizzle across the NW Piedmont during the early overnight hours given a weak ENELY upslope component. Any post-frontal drizzle and associated stratocu will be short-lived as low-level dry cool air advects south into the area after midnight. Additionally, expect a period of post-frontal NELY wind gusts into the upper teens to lower 20s as CAA commences. Today will be the last day of above normal temps before the well advertised cooler temps arrive. Highs in the mid 80s NE to around 90 south. Lows tonight in the upper 50s to lower 60s north to mid 60s south. && .SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/... As of 128 AM Tuesday... The post-frontal stratocumulus/stratus should be mostly confined to the Piedmont Wednesday morning, then skies are expected to become partly to mostly sunny in all areas in the afternoon. A refreshing NE breeze will advect in much drier and cooler air. Expect highs only in the 70s, except a few lower 80s near the NC/SC border area. Then, mainly clear and cool Wednesday night. The most comfortable night in recent memory. Lows in the 50s, with some upper 40s north- central Piedmont. && .LONG TERM /THURSDAY THROUGH MONDAY/... As of 355 AM Tuesday... Surface high pressure will remain over the area late week into the weekend, before slowly shifting offshore late weekend into early next week. Meanwhile, mid/upper level ridging will build over the area late week and linger across the region during the weekend into early next week. This will result in dry conditions with below normal temps for late this week, with temps moderating to near to slightly above normal for the weekend into early next week. Thus, expect highs will generally be in the 70s for late week, with lows in the the 50s. A few of the rural cold spots may see temps drop into the upper 40s Friday mornings. Temps will moderate some this weekend into early next week, with highs expected to climb back into the 80s with lows around 60/lower to mid 60s. && .AVIATION /12Z TUESDAY THROUGH SATURDAY/... As of 632 AM Tuesday... The FAY TAF will be AMD NOT SKED until further notice. There has been a failure of the ASOS with missing surface observational data. Generally VFR conditions are forecast today. A backdoor front will bring a 20 percent chance of an MVFR CIG/VSBY shower this afternoon and early evening; otherwise MVFR to IFR CIGS will develop tonight. These CIGS will lift to MVFR then VFR on Wednesday as the dry and cool high pressure builds in from the north. .Outlook beyond 12z Wed... VFR conditions expected Thursday through Saturday. && .EQUIPMENT... Unrelated to the helium shortage effecting the Carolinas in NWS Eastern Region, an azimuth motor failure will result in missing upper air observations at GSO through 12Z Tue. The FAY ASOS has failed. Daily climate information will be estimated until service is restored. && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Badgett/BSD NEAR TERM...CBL SHORT TERM...Badgett LONG TERM...BSD AVIATION...Badgett EQUIPMENT...RAH is the U.S. government's official web portal to all federal, state and local government web resources and services.