Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 251842 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 240 PM EDT TUE OCT 25 2016 .SYNOPSIS... Cool high pressure will extend into our region from the north through Wednesday night, before shifting offshore early Thursday. A cold front will move into the area from the northwest Thursday night. && .NEAR TERM /through tonight/... As of 210 PM Tuesday... High confidence in quiet weather through tonight. With the front having settled to our south and high pressure ridging nosing in from the north, combined with slowly rising heights aloft (as the Canadian Maritimes vortex fills and lifts out with weak mid level shortwave ridging building in from the west) and steady warming in the 925-700 mb layer, we should see dry weather and good radiational cooling tonight, with only a few thin high clouds spreading in overnight from the NW. With calm or nearly calm air near the ground, the dearth of clouds, and dewpoints expected to slip into the 30s over most of central NC, there remains a chance (albeit small) of patchy frost in some outlying rural and sheltered areas of the northern Piedmont for an hour or perhaps two late tonight. But any frost would be minimal in coverage and duration, due to the marginal near-ground RH and brief predawn dip in temps, insufficient for an advisory of any kind. Expect wide-ranging lows of 36-42, with these lower values confined to the aforementioned outlying locations. -GIH && .SHORT TERM /Wednesday through Thursday night/... As of 240 PM Tuesday... The axis of the weak shortwave ridge will shift eastward over the Southeast states Wed, as the axis of the Canadian-source surface ridge begins to shift east and off the East Coast. Expect another mostly sunny day with below-normal thicknesses indicating highs in the mid-upper 60s. Milder lows expected Wed night as the return flow around 925-850 mb anticyclones starts to draw low level moisture into the area, advecting first into the western CWA. Lows from mid 40s NE to upper 40s and around 50 far south and west. A fast-moving and strengthening shortwave swinging ESE through the Great Lakes and Northeast Thu/Thu night will help draw a front into NC from the NNW, likely not arriving until late Thu night. Have low confidence in our area receiving any significant precip, considering that the vorticity will be shearing through the mid level trough axis as it passes through, the upper divergence will be minor and mostly to our north, and PW is projected slightly lower than what the models showed yesterday. That said, forecast soundings do show some marginal instability late in the day into the evening, although surface dewpoints may not get quite high enough for anything more than an isolated storm or two. Will stick with low chance pops (20- 35%), higher north and lower south, from mid afternoon through the evening, with the isolated thunder risk confined to the north. Warm sector highs Thu in the 70s. Thu night lows in the 50s, as the front will be delayed until late and may not work much more southward than the northern sections of NC prior to daybreak Fri. -GIH && .LONG TERM /Friday through Monday/... As of 305 AM Tuesday... Winds will shift to NW behind the front, though no appreciable CAA will follow, resulting in little impact to temperatures. Surface high pressure will build across the area Friday and Saturday, then sink southward over the Gulf Coast Sunday as another shortwave crosses north of the area. Moisture return with this system is lacking and a dry frontal passage looks likely at this time. Normal to above normal temperatures expected through the period. && .AVIATION /18Z Tuesday through Sunday/... As of 145 PM Tuesday... High confidence in continued VFR conditions through the next 24 hours, as surface high pressure extends into the area from the north. With deep dry air in place, very few clouds are expected, primarily confined to high thin clouds spreading in from the northwest. Surface winds will be light and variable under 6 kts through Wednesday. Looking beyond 18z Wednesday: With one exception, VFR conditions will remain dominant for the rest of the week and into the weekend. The exception will be late Wed night through Thu morning, as we get into a mild flow from the south or southwest which will bring a period of sub-VFR (likely MVFR, with brief early-morning IFR possible) stratus, and potentially some daybreak fog. The chance for MVFR cigs will hold into late Thu afternoon and Thu evening as a few showers and isolated storms pass through the area ahead of a cool front pushing in from the north-northwest. MVFR cigs may linger near FAY through late Thu night. Then, high pressure will build in both at the surface and aloft, leading to mostly dry weather and VFR conditions Fri through the weekend. -GIH && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Hartfield NEAR TERM...Hartfield SHORT TERM...Hartfield LONG TERM...30 AVIATION...Hartfield is the U.S. government's official web portal to all federal, state and local government web resources and services.