Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 191640 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 1140 AM EST Sun Feb 19 2017 .SYNOPSIS...
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An upper level trough will shift off the Carolina coast by early this afternoon. High pressure will build into our region behind the exiting low pressure system tonight through Monday night, then move off the East Coast on Tuesday.
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&& .NEAR TERM /THROUGH TONIGHT/... As of 910 AM Sunday... The mid level trough sitting overhead this morning will continue to gradually fill and deamplify as it shifts ESE and off the coast through early afternoon, with rising heights aloft and high pressure building in at the surface from the west. Deep drying and stabilization will translate to generally clear skies today. Observed low level thicknesses this morning are around 35 m above normal, and these values combined with abundant sunshine, decent mixing, and nearly negligible cold air advection support highs similar to yesterday, in the low-mid 70s. -GIH Earlier discussion from 255 AM: A weakening upper level low will scoot east across our region this morning, exiting offshore this afternoon. Subsidence on the backside of this system and a developing low level nw flow will aid to diminish cloudiness later this morning through the afternoon. Increasing sunshine and a low level west-sw surface flow will boost afternoon temperatures back into the 70-75 degree range. Tonight, high pressure at the surface and aloft will be positioned to our west-nw, maintaining a tranquil weather pattern. Under mostly clear skies and a light wind regime, temperatures will drop back into the low-mid 40s. -WSS && .SHORT TERM /MONDAY AND MONDAY NIGHT/... As of 255 AM Sunday... Upper level ridge and attendant sfc ridge will be overhead Monday, maintaining the dry and very mild conditions. While low level thicknesses change little in the west, a backdoor cold front will drop into our northern coastal plain counties by afternoon, resulting in lower thicknesses compared to this afternoon. This translates to high temperatures about 3 degrees cooler than today northeast of Raleigh. High temperatures Monday near 70 northeast to the mid 70s sw. Low level ely flow will cause moisture to bank up along the higher terrain of western NC, leading to the formation of a low stratus late Monday night. Some of the stratus may spill into our western counties after midnight, though no precipitation expected at this time. Min temps near 40 ne to the mid 40s west. && .LONG TERM /TUESDAY THROUGH SATURDAY/... As of 255 AM Sunday... The upper level ridge over the eastern U.S. will shift east over the Atlantic as the next weather system approaches from the west. As the aforementioned system moves east, a closed low will break away from the northern stream trough late Tuesday and move east-southeast over the Gulf of Mexico on Wednesday (well south of the North Carolina). Meanwhile, the remnant northern stream trough will move over Central NC. The strength of the trough and whether it will generate light rain is still in question, however a slight chance for light rain cannot be ruled out Tuesday Night into Wednesday. Regardless, accumulations should be minimal as the best moisture will be well south of the area. At the surface, the high that had been ridging into the region will push eastward off the Mid-Atlantic coast on Tuesday, resulting in a more southeasterly then southerly return flow setting up over Central NC. The lingering dry air over the region may help keep rain from reaching the ground Tuesday night. Warm advection will increase as the southerly flow increases, resulting in a moderating temperature trend for Tuesday through Friday night. With the continued surge of warm air and the frontal passage not expected until the weekend, temperatures will remain well above normal through Friday night (highs in the mid to upper 60s Tuesday, increasing into the mid 70s Wednesday through Friday. Lows will follow a similar trend, upper 40s Tuesday night into the low to mid 50s by Friday night). There are still significant model differences for Friday onward with respect to the timing of the frontal system and associated weather. Generally, expect increasing chances for rain, with the highest chances Friday Night/Saturday ahead of the front. Temperatures, particularly the overnight lows, will decrease behind the front. However, temperatures still appear to remain slightly above normal. && .AVIATION /18Z Sunday through Friday/...
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As of 1140 AM Sunday... High confidence in VFR cigs/vsbys at all central NC terminals through Monday afternoon. A few clouds based around 3500 ft AGL will pass near INT/GSO through early-mid afternoon today, but otherwise skies will be cloud-free as high pressure builds in from the NW. Surface winds from the NW may gust infrequently to 15-20 kts through this afternoon, subsiding by 22z. Looking beyond 18z Mon, VFR conditions will hold through Mon evening. As the high pressure ridge shifts off the East Coast, a return flow of low level moisture will bring a chance for sub-VFR cigs/vsbys late Mon night/Tue morning especially at Piedmont TAF sites (INT/GSO/FAY). We will see this chance for late-night and early-morning sub-VFR fog/stratus repeat areawide through the remainder of the work week. A few showers are possible late Tue night through Wed morning as a weak upper trough crosses the area, but VFR conditions should remain dominant. -GIH
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&& .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...WSS/GIH NEAR TERM...Hartfield/WSS SHORT TERM...WSS LONG TERM...KCP AVIATION...Hartfield

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