Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 231722 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 125 PM EDT Thu Mar 23 2017 .SYNOPSIS... Continental polar high pressure will continue to modify over the srn Middle Atlantic states through tonight. A warm front will retreat north across the region on Fri, as the high drifts east toward Bermuda. && .NEAR TERM /THROUGH TONIGHT/... As of 1110 AM Thursday... Little adjustment required to the near term forecast. An area of high pressure at the surface and aloft will maintain relatively cool and dry conditions across central NC through tonight. After a chilly start to the day, with early morning temperatures in the upper 20s-lower 30s, temperatures this afternoon should recover into the low-mid 50s north and upper 50s south. Aside from a few passing thin cirrus, skies will remain sunny. ~WSS The surface ridge will continue to extend across NC tonight. Associated calm to light ESEly surface winds, combined with a mainly clear sky, aside from continued occasional thin cirrus, will favor strong radiational cooling and a light freeze away from urban centers. Low temperatures in the upper 20s to middle 30s. ~MWS && .SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/... As of 355 AM Thursday... Surface high pressure will drift to near and just north of Bermuda; and associated return flow across the sern U.S. will allow a warm front to retreat north through central NC during the day Fri. Both temperatures and moisture will consequently be on the increase, with highs in the mid-upper 60s N and NW, to lower 70s in the S, and surface dewpoints in the 40s to near 50 degrees. The increasing low level moisture values, and broad WAA regime, will favor a scattering of flat/fair weather cumulus trapped beneath a subsidence inversion that will have become established courtesy of mid-upper level ridging aloft. Not as cool Fri night, though with decent radiational cooling potential as the Bermuda surface ridge continues to extend west into NC. Patchy radiation fog may result, with low temperatures in the middle 40s to around 50 degrees. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... As of 320 AM Thursday... The extended will primarily feature a Bermuda high and warm southerly flow, with highs in the 70s, at least 5-10 degrees above normal. Continued moistening Friday night may lead to some stratus near and west of the Yadkin River Saturday morning, and a pronounced cap will likely trap this moisture and yield partly to even mostly cloudy by Saturday afternoon. Meanwhile, and upper low over the Deep South will lift west of the mountains Saturday night, providing a glancing blow of DECENT height falls that should erode the cap and permit showers and storms, mainly west on Sunday. Current timing suggest early day clouds and showers, an extension of upstream convection on Saturday, may impede warming and destablization enough in the west to limit any severe with potential, though an axis of instability between the morning convection and the stronger cap to the east could support an isolated severe threat given 30-40kt bulk shear. The cold front associated with Sunday`s lifting upper low looks as though it will stay well west of the mountains and NC will stay in the warm sector, with another, less amplified system progged to cross the area on Tuesday. The latest ECMWF is much less amplified with this wave that it`s previous run, as well as the 00Z/23rd GFS runs. This system could be interesting given the potential for decent destablization in the warm sector on Tuesday and possibility of locally enhanced shear associated with the shortwave. For now, chance POPs still look most appropriate. After that, a backdoor cold front is forecast to sink south into NC by mid to late week, though the presence of the sub-tropical ridge makes frontal passage much less certain. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/...
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As of 125 PM Thursday... High probability that VFR conditions will occur across central NC through 00Z Saturday. The exception will be the potential for a few patches of MVFR visibility due to fog in sections of the southern Piedmont, the Sandhills, and the southern coastal plain, between 10Z- 12Z Friday. The area of high pressure which has provided the VFR conditions will drift offshore Friday. The return sly flow will begin to advect a warm moist air mass into central NC. The arrival of this air mass will lead to higher chances for early morning fog or low stratus Saturday morning and Sunday morning. An approaching low pressure system will increase the threat for scattered showers Sunday through Tuesday. With the moist air mass in place, there will be periods of IFR/MVFR ceilings during this same period.
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&& .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...MWS NEAR TERM...WSS/MWS SHORT TERM...MWS LONG TERM...SMITH AVIATION...WSS is the U.S. government's official web portal to all federal, state and local government web resources and services.