Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 180600 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 200 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 /UNTIL 6 AM MONDAY MORNING/... As of 933 PM Sunday... Pressure gradient will tighten overnight and into the day Monday as Hurricane Jose continues to move north, and remaining well east of the NC coast. As such, expect the calm to light winds currently being reported to become northerly at 4 to 7 kts across central NC, strongest in the east. While this mixing should preclude widespread fog development, NAM fcst soundings suggest indicate the low-level moisture along the coast spreading inland and lowering with time. Otherwise, we will continue to see in persistence in terms of overnight lows, ranging from 63-64 in the typically cooler spots to upper 60s SE. && .SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/... As of 200 PM Sunday... As Hurricane Jose moves up the east coast there will be little to no impact for central NC aside from more clouds and the possibility of some rain band showers moving through the eastern counties but the results will be inconsequential. There will be some wind gusts up to 15 kts or so mainly out of the NNE. Coolest temperatures will once again be in the northeast with warmest values in the southwest Piedmont. Expect highs between 80-85 degrees. Clouds will begin to recede on Monday night from southwest to northeast and temperatures will dip into the low to middle 60s. && .LONG TERM /TUESDAY THROUGH SUNDAY/... As of 325 PM Sunday... While there`s a lot to keep our eyes on in the long term period, central NC will be in between significant weather features for most of the period. At the start of the period on Tuesday, a west to northwest flow aloft is expected as weak troughiness aloft develops extends from Jose southwest into our region on Wednesday and Thursday. The weakness aloft eventually closes off near TN/AL on Friday and then drifts west on Saturday. The lower level flow which is initially northwest to northerly on Tuesday and Wednesday, becomes easterly on Thursday and Friday. With limited forcing for ascent, dry and generally fair weather is expected with temperatures a few degrees above normal. The forecast become increasingly more complex late in the weekend into early next week. Jose which may be evolving into a sub-tropical or post-tropical system appears inclined to head westerly toward the mid Atlantic coast. At the same time, Hurricane Maria is forecast to be approaching the central/northern Bahamas. The interaction of these two systems and the weakness aloft over the lower MS Valley or Deep South will have big implications in the sensible weather across the area on Monday and beyond. For now, followed WPC guidance with seasonable temperatures and slight chance PoPs on Monday. -Blaes && .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...CBL SHORT TERM...RE LONG TERM...BLAES AVIATION...WSS

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