Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 181946 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 245 PM EST Sat Feb 18 2017 .SYNOPSIS... An upper level trough will approach from the west today and cross the southeastern U.S. tonight through early Sunday. High pressure will build into our region behind the exiting low pressure system Sunday night and Monday. && .NEAR TERM /through tonight/... As of 240 PM Saturday... Still looks like a very minimal precip event for central NC into this evening. The mid level ridge axis over eastern NC will continue to shift ENE and offshore through tonight, as the mid level low now near Memphis fills and deamplifies a bit as it tracks to the E then ESE into the Carolinas overnight. Both moisture and forcing for ascent out ahead of this low are rooted in the mid and upper levels, including a band of decent upper divergence, mid level DPVA, and mid level height falls of 50-70 m, acting on a band of enhanced elevated moisture aloft noted on water vapor imagery now streaming through SC and western NC. But lift in the low levels is negligible, with fairly dry air below 700 mb, so the precip band now running from KY through SW NC and W SC/E GA will have a tough time generating measurable precip at the ground as it progresses to the NE. Have made minor tweaks to earlier update, retaining low chance pops (for measurable light rain) over the SW CWA for a few hours late this afternoon into early evening, trending to just scattered sprinkles elsewhere for a few hours during the evening as this precip band translates to the NE, with much of the precip evaporating before it hits the ground. Skies will continue trending W to E to mostly cloudy this evening, then trending back to partly cloudy overnight as the dry slot now pushing into W GA shifts over our area. Expect mild lows mostly in the low-mid 40s tonight, with expectations of rebounding dewpoints as the mid level low shifts into the area, preceded by passage of a weak surface trough through the area. -GIH && .SHORT TERM /Sunday through Sunday night/... As of 245 PM Saturday... Quiet weather with very few clouds and warm temps. A light surface flow from the NW will persist Sun as high pressure builds in from the west. We`ll likely see a few clouds in the morning as a vorticity lobe dives into the base of the shortwave trough over the area. But as this trough pushes ESE and offshore, rising heights and warming aloft will bring generally clear skies. Thicknesses should remain well above normal, similar to today`s readings, indicating highs from around 70 to the lower 70s. Lows once again mostly in the lower to mid 40s Sun night under clear skies. -GIH && .LONG TERM /TUESDAY THROUGH FRIDAY/... As of 205 AM Saturday... The surface high that had been ridging into the region will lift off to the northeast on Tuesday, with a more southeasterly then southerly return flow setting up over Central NC by Wednesday morning as a subsequent warm front slides north through the area. Aloft, the ridge over the eastern U.S. will shift off the coast and weaken as the next weather system approaches. A closed low will break away from the northern stream trough late Tuesday, then slide slowly east-southeast over the Gulf of Mexico on Wednesday (well south of the North Carolina). Meanwhile, the northern stream energy will largely pass to the north of Central NC. Some light rain is possible over the area Wednesday/Wednesday Night, but accumulations should be minimal as the best moisture will be well south of the area. A better chance for descent rainfall will come Friday or Saturday a low pressure system develops over the northern high plains and progresses east. The parent low will track northeast through the Great Lakes as the attendant cold front extends south into the Gulf. The strongest warm advection into the Carolinas will be just ahead of the front Friday/Friday night, with the frontal passage on Saturday. Expect moderating temperatures through Friday Night (highs maxing out in the mid 70s Friday and lows in the low to mid 50s Friday Night), decreasing thereafter. && .AVIATION /18Z Saturday through Thursday/... As of 105 PM Saturday... High confidence in VFR conditions through Sunday. As an upper low crosses the region late today through tonight, clouds will increase across central NC from SW to NE during this afternoon, with a period of broken to overcast skies very late afternoon through the evening. However, cigs are likely to stay above 5000 ft AGL. A few sprinkles or light showers are possible at central NC terminals 21z-03z, but vsbys will stay VFR. Light winds mainly from the SW are expected this afternoon, veering to W then NW tonight, lasting through Sunday. Looking beyond 18z Sun, VFR conditions will dominate through at least Mon evening. Model differences then crop up regarding a passing mid level trough through the region, reducing confidence, but there is at least a chance of sub-VFR conditions late Mon night/Tue morning, and again late Tue night/Wed morning and Wed night/Thu morning as we get into moist SW flow. -GIH && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...WSS NEAR TERM...Hartfield SHORT TERM...Hartfield LONG TERM...KC AVIATION...Hartfield

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