Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 191955 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 255 PM EST Sun Feb 19 2017 .SYNOPSIS... An upper level trough will shift off the Carolina coast this afternoon. High pressure will build into the region behind the exiting low pressure system tonight through Monday night, then move off the East Coast on Tuesday. && .NEAR TERM /THROUGH TONIGHT/... As of 130 PM Sunday... Quiet and mild weather tonight. The mid level trough is now shifting off the NC coast, and heights aloft will continue to rise over NC while high pressure builds in at the surface. A shallow layer of moisture that has managed to sneak past the mountains is generating a few high-based flat cumulus over the NW CWA this afternoon, but these will clear out later this afternoon with increased mixing of drier air within the boundary layer. Clear skies are expected tonight, with light winds slowly veering to northerly overnight. Expect lows fairly comparable to this morning`s readings, from around 40 to the mid 40s. -GIH && .SHORT TERM /Monday through Monday night/... As of 150 PM Sunday... The center of a high pressure ridge will drift across southern Quebec during this time frame while nosing southward through central NC. Dry and deeply stable air will persist through Monday, yielding mostly sunny skies, with just a few high clouds within fast northwesterly upper flow. Thicknesses will start out a bit lower than in the last couple of mornings, particularly over the NE sections of the forecast area, beneath the heart of the ridge axis. But values will still be well above normal, supporting highs from the upper 60s NE to the mid 70s in the far southern CWA. As the ridge axis shifts to our east Mon night, resulting in a southeasterly and southerly low level flow into central NC, low level moisture will steadily advect into the area, with increasing moist upglide focused around 290K across the western CWA overnight. Will have increasing clouds Mon night, especially in the west, with the relatively cooler ridge lingering in the NE CWA. Expect lows from the upper 30s NE ranging to the mid to perhaps upper 40s in the western CWA. -GIH && .LONG TERM /TUESDAY THROUGH SUNDAY/...
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As of 254 PM Sunday... Tuesday will begin with the upper level ridge axis right overhead and a surface low pressure system over New England. Clouds will increase throughout the day ahead of a frontal system over the Mississippi Valley. Highs in the mid to upper 60s. As the surface high moves offshore and the front gets closer, warm air advection will begin and temperatures on Wednesday will soar into the mid 70s. As the front moves through there will be some chance for rain showers but not a soaker of a day by any means. Despite the front moving through it eventually washes out and the high pressure that was over new England dips southward off of the Carolina Coast and thus no real change in airmass occurs as return flow keeps warm air moving into central NC. This will keep temperatures in the mid to upper 70s for Thursday as frontogenesis begins to occur across the Appalachians as a low pressure system develops over the plains and pushes eastward. This will give slight chances for rain across the north on Thursday but again with meager moisture content as a warm front organizes and pulls away to the north as the parent low moves front the Plains northeastward towards the Great Lakes. The timing of the evolution of this system is in a big of question with the GFS showing a quicker progression of the advancing cold front and the ECMWF still a little slower but faster than yesterday. As a result the best chance for some significant rainfall and perhaps a thunderstorm or two will begin on Friday and progress through Saturday but clearing out for Sunday. Highs in the 70s through Saturday before easing back into the mid 60s for Sunday.
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&& .AVIATION /18Z Sunday through Friday/... 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 && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...WSS/GIH NEAR TERM...Hartfield SHORT TERM...Hartfield LONG TERM...Ellis AVIATION...Hartfield is the U.S. government's official web portal to all federal, state and local government web resources and services.