Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 260125 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 925 PM EDT Sat Mar 25 2017 .SYNOPSIS... Bermuda high pressure will extend west into the Carolinas and VA through Sunday. A weakening upper level disturbance will cross northwest of our region on Sunday. && .NEAR TERM /THROUGH TONIGHT/...
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As of 925 PM Saturday... Weak southerly moist warm air advection between the Bermuda high over the western Atlantic and a slow moving low pressure system lifting NE through the Middle MS Valley will result in partly to mostly cloudy skies overnight and continued mild temperatures. With the strongest surge of warm air advection remaining along and west of the mountains, it will remain dry overnight with pockets of low clouds possible, primarily along the eastern slopes. Mild overnight lows generally in the mid 50s.
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&& .SHORT TERM /SUNDAY AND SUNDAY NIGHT/... As of 255 PM Saturday... A lead s/w rotating around the mid MS Valley upper low will lift newd from eastern TN into the central Appalachians Sunday, brushing our nw sector. This system projected to weaken with time and while atmosphere continues to moisten, model rh cross sections still depict a decent layer of dry air in the mid levels of the atmosphere. Accordingly, models have been trending drier, so will follow a similar trend. Plan to confine chance PoPs to the NW Piedmont, with slight chance PoPs elsewhere across the Piedmont. Over the east and far south sections, will advertise PoPs less than 15 percent. Expect quite a bit of cloudiness, limiting insolation. Still, warm sly flow along with partial sun should be able to boost temperatures back into the low-mid 70s. Continued mild Sunday night under variably cloudy skies. Weak confluence and a series of weak perturbations aloft will continue a minor threat for a few showers over the NW Piedmont. Elsewhere, probability of a shower appear too remote to mention at this time. Overnight temperatures in the mid-upper 50s. && .LONG TERM /MONDAY THROUGH SATURDAY/... As of 230 PM Saturday... A warm, moist airmass will be in place to kick off the work week. Precipitable water in excess of 1.2 inches and highs Monday through Wednesday reaching the mid 70s to lower 80s will provide modest instability and widely scattered showers Monday, with coverage ramping up somewhat on Tuesday as a progressive but relatively weak short wave moves east across the area. Timing of the short wave will be favorable to tap afternoon instability and a few thunderstorms will be possible in the afternoon...especially east where instability and upper diffluence are favorably aligned ~18-21Z. Dry and continue warm temperatures are initially on tap Wednesday as ridging aloft builds over the area ahead of another upper low moving into the central Plains. High pressure over the Great Lakes will surge south ahead of the Plains system, pushing a dry backdoor cold front south into the state later Wednesday, but highs will have time to reach the mid and upper 70s ahead of the cooler air. The "seasonally-adjusted" cold air damming setup will promote overrunning rain in the west as early as Thursday afternoon. PoPs will be ramping up Thursday night and lingering all the way through Friday night as low level southerly flow increases ahead of the Plains system. Low level instability will be meager at best, with no indication as yet that we might see a thermal moisture boundary encroach inland, As such, will have only a slight chance for elevated thunderstorms on Friday. Highs both Thursday and Friday will be mainly in the 60 to 65 range, with some lower 60s across the piedmont and northern coastal plain where cool air will be deeper. Lot of uncertainty as to how the Plains system evolves, i.e. the latest GFS re-establishes cool air advection with development of a coastal low, while the 00Z ECMWF was scouring out the cool airmass and allowing highs to rocket quickly back to the upper 70s...will go middle of the road 70 to 75 for now to await some consensus. && .AVIATION /00Z SUNDAY THROUGH THURSDAY/... As of 720 PM Saturday... 24-hr TAF Period: VFR conditions will prevail through this evening and most of tonight. All terminals will see a potential for MVFR or IFR ceilings (developing in assoc/w an increasingly moist southerly return flow) for several hours Sunday morning (10-15Z). Ceilings are expected to lift to VFR (3-4 KFT) by noon, however, ceilings may persist near the VFR/MVFR cut-off at 3-4 KFT the remainder of the afternoon. -Vincent The weather pattern will be unsettled through mid-week, suggesting that periods of sub VFR conditions are probable, primarily in the form of low ceilings during the overnight into the early morning hours. An approaching low pressure system will trigger scattered showers across central NC late Monday night through Tuesday. A backdoor cold front may drop into the region Wednesday, setting up a possible CAD event for the later half of the work week, and attendant sub VFR conditions. -WSS && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...MWS NEAR TERM...CBL SHORT TERM...WSS LONG TERM...mlm AVIATION...Vincent/WSS is the U.S. government's official web portal to all federal, state and local government web resources and services.