Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 180158 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 900 PM EST Sat Feb 17 2018 .SYNOPSIS... A weak cold front will approach from the west and cross our region tonight. High pressure will build into the area Sunday, then quickly drift offshore Sunday night. && .NEAR TERM /THROUGH TONIGHT/...
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As of 900 PM Saturday... Latest surface analysis shows a series of weak surface areas of low pressure residing along the spine of the southern Appalachians. A mid to upper level short wave will cross parts of the Ohio Valley tonight, ejecting these features and the associated band of light precipitation east into the Atlantic Ocean, likely near to slightly after midnight. In the meantime, expect these leftover showers to continue to weaken as they cross from west to east, with most areas seeing mostly drizzle to light rain showers. Little in the way of rainfall accumulation is expected. Skies should clear rather rapidly behind the shortwave, as dry air mixes into the mid to upper levels of the atmosphere. With surface moisture likely to linger, there is a chance of some fog formation, but not highly certain of timing or location at this point. So will limit the visibility reduction to no worse than 1-2 miles for now, but wouldn`t be surprised to see isolated vsby drops below a mile. Expect early morning min temps in the mid 30s to near 40 north, and low-mid 40s south. If clouds are slow to depart, min temps may end up being 2-3 degrees warmer than forecast, and vis a versa if clearing is a bit more rapid than expected, especially across the Triad.
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&& .SHORT TERM /SUNDAY AND SUNDAY NIGHT/... As of 300 PM Saturday... Sunday, high pressure will build in the wake of the departing s/w. Subsidence and drier air associated with the high will lead to rapid dissipation of any fog/low clouds that develop, with mostly sunny skies expected from late morning into the afternoon. Mild conditions expected for this time of year with afternoon temperatures well into the 50s to around 60 north, and the low-mid 60s south. The sfc high will depart early Sunday evening, setting up a low level return flow. Another isentropic upglide/lift event projected to occur overnight as a minor s/w lifts newd from the TN Valley/southern Appalachians into central NC. Based on the expected trajectory of the s/w, expect the highest threat for rain across the nw half of central NC. Based on timing, expect the rain to hold off until well after midnight, potentially not starting until close to daybreak. Temperatures will remain mild enough so that precip expected to be all liquid. min temps will vary from the upper 30s/near 40 northeast, to the mid-upper 40s south and west. && .LONG TERM /MONDAY THROUGH SATURDAY/...
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As of 130 PM Saturday... ...Unusually warm temperatures will likely shatter records during the upcoming week... The daily record highs and record high minimum temperatures are included in the Climate section below for February 20 and 21 (Tuesday and Wednesday). These are the most likely days that will see new records. We will add to this the chance of record warmth continuing Thursday (February 22), and this may be extended in later forecasts due to the slowing of the decay of the strong upper ridging. To start off the warming, a warm front will push northward into the area. Some areas of light rain and showers are expected, with the highest POP in the NW zones into early Monday. Guidance continues to favor the warm front and WAA drying advection to bring clearing into the region Monday afternoon, especially south and west. Highs should moderate back into the 60s, except some upper 50s north. This may be tempered if the cloudiness persists into the afternoon more than currently expected. The main storm track is forecast to remain to the west and north of central NC this week. This occurs as a very strong and unusual subtropical ridge is forecast to set up just off the south Atlantic coast, most likely waxing Tuesday and Wednesday. A battle between arctic air over the northern Rockies into the upper Midwest and the record warmth in the southeastern states will lead to an active storm track, but much of the significant rain is expected to remain just to our NW, or from the Appalachians west and north. One front will likely make a run at us on Thursday, but due to the extensive upper ridge, will likely stall and return north on Friday. Most models now depict the strong ridge to remain in place into next weekend, with the potential for more record warmth depending on the position of the "backdoor" fronts. Sensible weather will be for only a slight chance of lingering light rain or drizzle Monday morning, otherwise increasing warmth and humidity Tue-Wed. leading to highs potentially in the upper 70s NW ranging into the lower 80s elsewhere. Some 83-84 degree readings will be possible from Laurinburg to Fayetteville) Tue-Thu. Lows in the 60s mid to late week will also likely set records. We will back off on highs some Thursday, especially NW given the increasing clouds and chance of showers associated with the slowing front. Otherwise, a return to SSW flow again Thursday night and Friday may extend well into next weekend. Highs again may surge toward records. More on this in later forecasts.
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&& .AVIATION /00Z SATURDAY THROUGH THURSDAY/... As of 633 PM Sunday... LIFR to MVFR conditions with period of light rain/drizzle will continue through 06z in the west to 08/09z in the east, when the passage of a cold front through the area, will lead to NW to SE clearing. There may be a brief period of IFR/LIFR visibility due to fog between 09-13Z Sunday in proximity of the Triad terminals and possibly KRDU, but forecast confidence is not high enough at this time to mention in the terminal forecast. VFR parameters expected Sunday but this will not last much into Sunday night as another low pressure system will begin to effect our area, leading to MVFR/IFR ceilings and areas of light rain late Sunday night through Monday. While an improvement in aviation conditions expected Tuesday through Thursday with periods of VFR parameters, a moderately moist atmosphere will lead to the probability of sub VFR parameters, primarily during the late night-early morning hours due to low clouds and patchy fog. && .CLIMATE... RDU Records: Date | High Year | High Min Year ------------------------------------------ 02/20 75 1939 62 1939 02/21 76 2011 55 1939 02/22 75 1897 60 1897 02/23 79 1980 57 1962 02/24 81 1982 58 1985 GSO Records: Date | High Year | High Min Year ------------------------------------------ 02/20 74 1922 56 1939 02/21 74 2011 50 1954 02/22 74 1925 57 1980 02/23 74 2017 52 1922 02/24 79 1982 55 1985 FAY Records: Date | High Year | High Min Year ------------------------------------------- 02/20 82 2014 60 1939 02/21 80 1991 61 1953 02/22 77 2003 56 1989 02/23 80 1922 55 1922 02/24 83 1930 60 1975 && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...WSS NEAR TERM...JJM/WSS SHORT TERM...WSS LONG TERM...Badgett AVIATION...CBL/WSS CLIMATE...Badgett is the U.S. government's official web portal to all federal, state and local government web resources and services.