Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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475 FXUS62 KRAH 220256 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 956 PM EST Tue Nov 21 2017 .SYNOPSIS... A weak area of low pressure will develop off the Florida coast, and then track quickly northeastward along the Southeast coast tonight. A cold front will move through the area on Wednesday. && .NEAR TERM /THROUGH TONIGHT/... As of 955 PM Tuesday... A few adjustments have been made to the near term forecast, primarily to the PoP. With the current radar trends are a bit more robust than previously thought, have increased pops and slowed the exit out of Central NC Wednesday morning. Have also added a slight chance of thunder across the far east between 06Z to 09Z. Previous Discussion (As of 700 PM): An area of low pressure has become well defined just off the FL panhandle. This system projected to eject east-northeast tonight and form another sfc wave off the NC coast by early Wed morning. This action will induce decent isentropic upglide overnight with the lift more concentrated over sections of the sandhills and coastal plain versus the western Piedmont. Based on current radar trends and trends in the near term model guidance, have tweaked PoPs up a bit initially over the western Piedmont, then shift focus over the eastern half of the forecast overnight. Expect rainfall amounts on the order a tenth of an inch or less over our western sections, and upwards of a quarter of an inch to less than a half inch over the east half. Partial clearing over the western Piedmont prior to daybreak may induce areas of fog. Min temps should vary from the mid 40s NW to the low-mid 50s SE. && .SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/... As of 236 PM Tuesday... A northern stream short wave, currently moving across the Midwest, will move east and sweep across central NC. Its attendant sfc cold front will move through during the morning into mid-day hours, followed by subtle CAA, subsidence and drying in its wake. Forecast soundings suggest skies will clear out during the late morning with sunshine by afternoon. The resulting airmass combined with afternoon sunshine will provide seasonable high temps...low-mid 60s. Northerly winds behind the front may become gusty in the late morning and afternoon, with gusts peaking up to 20 mph at times. High pressure will gradually build to our north late Wednesday and Wednesday night. Despite CAA earlier in the day, high clouds moving up from the south combined with some lingering light wind (sfc high center to our north) will result in highs a few degrees warmer than they otherwise would be under clear calm conditions. Look for lows from the lower 30s north (lighter wind closer to the high center) to upper 30s south (where thicker highs clouds will be found). && .LONG TERM /THURSDAY THROUGH TUESDAY/... As of 210 PM Tuesday... High pressure and its associated cold airmass to the north will expand into North Carolina on Thursday. A brief warmup will occur Friday into Saturday ahead of the next cold front that will pass through Saturday afternoon and evening. Very amplified trough in the eastern US Sunday will quickly move eastward with axis off the coast by Sunday night. Mid-level ridging builds into the area Monday and Tuesday. Temperature forecast for Monday has been adjusted upward a few degrees as trough looks to be moving faster than previous guidance was suggesting. If future model runs continue to show quick trough progression, temperature forecasts for Monday and Tuesday will likely be adjusted upward even further. Waves of low pressure off the southeast US coastline Thursday and Friday will keep more substantial rain to the east and south of the region. Some spotty light rain or sprinkles may clip the extreme southeast areas Friday night but confidence is decreasing that any rainfall will make it that far west and north. Otherwise, it will be a rather dry period in the longer range. && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/... As of 700 PM Tuesday... Aviation conditions will deteriorate from the south later this evening through the overnight as ceilings will lower into the MVFR category, beginning around 03Z. In addition, areas of rain showers will expand in coverage, particularly in vicinity of KFAY, KRDU, and KRWI between 05Z and 09Z. After 09Z, pockets of IFR/LIFR ceilings may develop for a brief period, with patchy fog over the western Piedmont, reducing the visibility to between 1-3 miles. A cold front will sweep across central NC Wednesday morning leading to improving aviation conditions as ceilings will lift and dissipate. Sfc winds will be brisk Wednesday morning through mid afternoon with gusts approaching 20 kts. VFR conditions Wednesday afternoon expected to linger through Sunday. && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ NEAR TERM...KC/WSS SHORT LONG TERM...Franklin AVIATION...WSS is the U.S. government's official web portal to all federal, state and local government web resources and services.