Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 250618 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 218 AM EDT Sat Mar 25 2017 .SYNOPSIS...
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Bermuda high pressure will extend west into the Carolinas and VA through the weekend. A weakening upper level disturbance will cross our region on Sunday.
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&& .NEAR TERM /THROUGH TONIGHT/... As of 950 PM Friday... Mid/upper level ridge centered over the region this evening will shift offshore overnight in advance of the closed cyclone advancing east across the southern central Plains. This will allow for a marked increase in high-level moisture from west to east after midnight, which based on IR imagery, be sufficiently opaque enough to impede radiational cooling. Mild overnight lows generally in the 50s(~ 7 to 10 F degrees above normal). Sfc ridge axis extending into the area from the parent high centered off the Carolina coast, should maintain it`s influence across the area overnight, which will result in only modest/marginal low-level moisture recovery overnight, and thus should further limit fog development. && .SHORT TERM /SATURDAY AND SATURDAY NIGHT/... As of 250 PM Friday... Warming trend continues Saturday as the high continues to drift away from our region, while an area of low pressure lifts from the southern Plains into the mid MS Valley. The approach of this feature will deepen our sw flow, increasing the moisture advection. This will lead to increasing cloudiness. While the atmosphere moistens, little if any lifting mechanisms noted to generate precip, aside from afternoon heating, Saturday through Saturday evening. Still, could see an isolated shower or two over the southern Piedmont but probability and coverage is too remote at this time to mention in the forecast. The warming air mass will translate to afternoon temperatures in the 70-75 degree range. Clouds will thicken and lower across the area Saturday night. This blanket of clouds will trap the heat gained Saturday, resulting in overnight temperatures in the 50s. A lead s/w ahead of the main low pressure system over the mid MS Valley will support a band of showers that will cross the mountains overnight, and may be in vicinity of the Yadkin River just prior to daybreak. Will retain the slight chance PoP over our western periphery late Saturday night. && .LONG TERM /SUNDAY THROUGH FRIDAY/... As of 240 PM Friday... A deep low pressure system will lift northeast into the Great Lakes Sunday. Its associated cold front will be weakening and essentially stalling as it edges up against the mountains Sunday and the parent low moves further northeast. This will result in central NC being nicked by only a glancing blow from the stronger dynamic regime associated with the upper system. So, despite our increasingly warm and moist airmass, convection will be favored northwest, with progressively smaller chances heading southeast. Some areas east of I95 may not see any activity at all. Will also maintain small chances for thunder west during the afternoon as instability will be modest and the east will be strongly capped in proximity to the Bermuda high offshore. Highs will reach the low to mid 70s, but the northeast may struggle to reach upper 60s due to heavier cloud coverage and potential shower activity. Warm and moist airmass remains in place in return flow around the Bermuda high with isolated convection on Monday and highs mostly in the upper 70s. A rather weak, but more southerly tracking short wave will be approaching from the west on Tuesday to increase our chance of convection somewhat due to its moving through during the heat of the day. Not seeing forcing that would readily signal potentially strong or well-organized convection, though, so will maintain 40-50 chance PoPs. Tuesdays highs will again climb way up into the 70s, with some lower 80s likely across the southern tier. Highs will again reach upper 70s Wednesday, but only isolated showers look doable in weak westerly low level flow and upper ridging over the area. Cooler high pressure makes a surge down the Atlantic coast on Thursday, with a backdoor cold front threatening to make it as far south as central NC, but low confidence in picking a model solution at this point. We will concurrently have a more southerly low pressure system taking shape over the southern Midwest which would feed moisture into the frontal zone and potentially give us a rain period Thursday night and Friday. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
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As of 215 AM Saturday... VFR conditions are expected for most of the TAF period, with a couple of exceptions. The first will be a chance of radiation fog around daybreak at RWI and FAY, where winds will be lightest in proximity to offshore high pressure, and also where surface dewpoints around 50 degrees are maximized relative to areas to the west. In addition, morning to midday heating of a seasonably moist air mass around Bermuda high pressure will favor the development of a field of stratocumulus that will initially develop around 2500- 3000 ft, and may be briefly broken at that time. Otherwise, SSWly surface winds will increase into the 6-12 kt range after 14Z, with occasional gusts into the teens kts, then lessen after sunset. Outlook: Late night-early morning fog and/or stratus, then MVFR range cloudiness as that moist layer is heated through midday, will be possible each day through early next week. Otherwise, a chance of showers and associated sub-VFR conditions mainly at Piedmont TAF sites will exist Sun, then again forecast area-wide on Tue.
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&& .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...MWS NEAR TERM...CBL SHORT TERM...WSS LONG TERM...mlm AVIATION...MWS is the U.S. government's official web portal to all federal, state and local government web resources and services.