Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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688 FXUS62 KRAH 180733 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 333 AM EDT Mon Sep 18 2017 .SYNOPSIS... Weak high pressure centered over the Northeast will extend south down the Appalachians into the Mid Atlantic through Tuesday. Hurricane Jose will pass well offshore of the NC coast today and tonight, then drift farther north offshore of the eastern seaboard on Tuesday. && .NEAR TERM /THROUGH TONIGHT/...
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As of 333 AM Monday... Little change to our weather pattern through tonight translates to a continuation in the warm and dry conditions across central NC in the near term. Areas of fog with pockets of locally dense fog probable this morning across portions of the coastal plain and northeast Piedmont. Currently have a SPS for the fog. If vsbys decline at other spots, an advisory may become necessary. The fog/low clouds that develop will lift/dissipate prior to 15Z. Otherwise, an area of high pressure to our west and Hurricane Jose` drifting northward well off the NC coast will maintain a nely low level flow, strongest over the coastal plain. The tightening of the sfc pressure pattern will result in steady north northeast winds 8- 12kts, strongest in the coastal plain, with infrequent gusts 15- 18kts. Adequate moisture in the lowest 10k ft along with weak convergence associated with the outer periphery of Jose` may initiate/sustain a shower or two this afternoon east of highway 1, more so along and east of a Warrenton-Wilson line. MOS temperature guidance has been averaging a degree or two too cool the past few days, and it appears that this trend is continuing today. Plan to advertise max temps in the lower-mid 80s, coolest far northeast. Tonight, Jose` makes its closest approach to the NC coast though expect little if any impacts across our region. Expect a light though steady nly sfc wind, most notable east and northeast of Raleigh. Expect partly cloudy ne and mostly clear skies elsewhere. Will likely see areas of fog or low clouds once again develop, primarily across the northern coastal plain into the northeast Piedmont. Min temps will vary from the lower 60s nw to the mid 60s east.
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As of 333 AM Monday... Tuesday and Tuesday night, Jose` moves up the eastern seaboard and away from our region. This movement will cause our low level winds to gradually back to a nwly direction, likely advecting a slightly drier air mass. This may inhibit the formation of fog/low clouds Tuesday night. Otherwise, expect mostly sunny-partly cloudy skies. With the atmosphere relatively dry and mechanisms for lift largely absent, expect limited chances for showers. High temperatures Tuesday will average a degree or two warmer, with mid 80s expected areawide. Min temps generally in the mid 60s.
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&& .LONG TERM /WEDNESDAY THROUGH SUNDAY/... As of 310 AM Monday... Central NC will be under the influence of high pressure through much of the extended forecast period, resulting in a predominantly dry forecast. Also, expect skies to be mostly sunny/partly cloudy through the period. Highs in the mid to upper 80s expected on Wednesday and Thursday, gradually decreasing thereafter as a result of possible advection of some cooler northerly air. Lows should mainly remain in the low to mid 60s through Sunday. Of more interest during this period will be the tropics. Jose is progged to meander off the NE U.S. coast through the week, with increasing uncertainty through the weekend. Meanwhile, Maria will be moving through the Caribbean, northwestward toward the CONUS. Her path and impacts from Sunday onward are still highly uncertain as they will depend heavily on Jose and how the two systems interact with one another. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... As of 200 AM Monday... An area of high pressure over the southern Appalachians will maintain a warm and dry weather pattern for most of central NC into mid week. Hurricane Jose` passing well offshore of the NC coast today and tonight will tighten the sfc pressure gradient, resulting in a steady nne sfc flow with sustained wind speeds 7-12 kts expected, strongest in the coastal plain. Occasional gusts 15-18kts may occur, again mainly across the coastal plain. This same flow will maintain a relatively moist layer of air in the lowest 10k ft of the atmosphere. This will lead to the development of late night- early morning low clouds and fog, especially across the eastern counties, or roughly along and east of highway 1, this morning. This will lead to an 1-3 hour window of IFR/LIFR ceilings in vicinity of KRWI, and possibly at KFAY and KRDU, around daybreak. Ceilings expected to gradually lift into the MVFR range after 14Z, then disperse prior to 17Z. Afternoon heating along with weak low level convergence due to Jose may trigger/support isolated showers over the coastal plain this afternoon. The probability of occurrence at KRWI appears too low at this time to mention in the forecast. As Jose` moves farther north Tuesday, the low level flow will gradually back to a more nwly direction, advecting a drier low level air mass and inhibiting the formation of low clouds and fog. Thus, should experience an extended period of VFR parameters across central NC Tuesday through Friday. && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...WSS NEAR TERM...WSS SHORT TERM...WSS LONG TERM...KC AVIATION...WSS is the U.S. government's official web portal to all federal, state and local government web resources and services.