Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC
Issued by NWS Raleigh/Durham, NC
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101 FXUS62 KRAH 011924 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 324 PM EDT Thu Oct 1 2026 .WHAT HAS CHANGED... * Increasing confidence in areas of fog, locally dense, early Friday. && .KEY MESSAGES... As of 320 PM Thursday... 1) Patchy dense fog will be possible late tonight and early Friday morning across mainly the Coastal Plain and eastern Sandhills. 2) Temperatures will remain well above average ahead of a cold front that will move south across central NC on Saturday. 3) Cloudy, much cooler, and periods of wet conditions will develop in cold air damming later Sat through the weekend. && .DISCUSSION... As of 320 PM Thursday... KEY MESSAGE 1... Patchy dense fog will be possible late tonight and early Friday morning across mainly the Coastal Plain and eastern Sandhills. As winds go very light to calm in many spots, more fog and very low stratus will be possible late tonight into early Friday morning across portions of central NC, mainly to the east of US Highway 1. Given the surface high will be centered farther offshore than this morning, southerly flow around the high will bring more moist air in the low levels from the Atlantic into those locations, with dew points increasing to the mid-to-upper-60s. Thus model guidance depicts a stronger signal for more widespread fog, locally dense, reaching farther NW into our area compared to this morning. Any fog will quickly dissipate after sunrise. KEY MESSAGE 2... Temperatures will remain well above average ahead of a cold front that will move south across central NC on Saturday. A sub-tropical high currently centered near the coast of the Carolinas will progress offshore today and settle across the southwestern North Atlantic through the weekend. At the surface, a ~1020 mb high now centered about halfway between Bermuda and the NC coast will drift to near Bermuda, while extending westward into the Southeast US, through Friday. Subsidence from the subtropical ridge aloft, and southerly, "return" flow around the Bermuda surface high, will contribute to additional warming of the airmass over the Carolinas and another day of summerlike temperatures on Friday. Low-level thicknesses should be about 5-10 m higher compared to today, favoring high temperatures in the upper- 80s to lower-90s. Fortunately, Friday afternoon humidity levels will again remain relatively low in the 40s percent courtesy of dewpoints mixing out to the lower-to-mid-60s. Still, the NWS Experimental HeatRisk is forecast to be Moderate across most of the region, meaning those who are sensitive to heat, especially those without cooling/hydration, are affected. Lows will also be above normal, in the lower-to-mid-60s tonight and in the mid-60s to 70 on Friday night. KEY MESSAGE 3... Cloudy, much cooler, and periods of wet conditions will develop in cold air damming later Sat through the weekend. Not a whole lot of change from the previous forecast. Still expect a positively-tilted srn stream trough/shear axis to progress slowly across the Southeast and Carolinas this weekend, just downstream and equatorward of a series of prominent shortwaves that will progress through a broad trough that will become centered over ern Canada. One nrn stream s/w will amplify as it tracks ewd across the nrn Plains and upper MS Valley on Sat and across the Great Lakes and the nrn mid-Atlantic/Northeast US Sat night and Sun. Expect a period of enhanced lift as the s/w energy interacts with the trough/shear axis over the region. The upper trough should amplify swd over the Eastern Seaboard on Mon before shifting ewd and offshore Mon night. At the surface, a front will settle swd across central NC Fri night/Sat, becoming quasi-stationary across SC and southeastern NC Sat night. A weak frontal wave is expected to lift newd along the boundary on Sun/Sun night, which may help the front retreat north and west a bit. Cool, strengthening high pressure will ridge swd into the area in the wake of the front Sat/Sat night as it progresses ewd from the Great Lakes to the Canadian Maritimes. A brief period of CAD may develop over the region Sat night, possibly lingering through Sun, especially with the expected rainfall acting to lock in the wedge across the NW Sun/Sun night. With all of the above in mind, expect rain to start Sat afternoon as isentropic lift increases within the trough/shear axis and ahead of the aforementioned s/w aloft and atop surface ridging, which will help lock in a CAD airmass. Rain should continue through Sun eve/night when the frontal wave finally moves away from the Carolina coast. There is still some uncertainty wrt overall rainfall totals, but generally expect 1-2 inches across central NC from Sat aft to Sun night. The WPC has central NC in a Marginal Risk for excessive rainfall on Sunday. If the CAD does indeed lock in, and with the expected rainfall, temperatures over the weekend will need to be adjusted downward further. A reinforcing cold front will move across the area Mon eve/night, with cool Canadian high pressure building in behind it and dry weather expected through mid-week. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/... As of 230 PM Thursday... 24 hour TAF period: VFR conditions will prevail across central NC through this evening. Model guidance is in pretty good agreement that areas of fog/mist will develop over the Coastal Plain and eastern Sandhills (including FAY and RWI) late tonight after 07z, lasting into early Friday morning. MVFR/IFR visibilities are likely, and isolated LIFR visibilities can`t be ruled out. Also can`t rule out patchy IFR/LIFR ceilings from very low stratus. The other TAF sites should stay VFR, and VFR will return everywhere by mid- morning. Winds will stay fairly light (less than 10 kts) and from the SW through the period, going calm in many spots tonight. Outlook: VFR conditions and dry weather will hold through Friday night. Widespread rain and associated sub-VFR conditions are expected across the entire region from Saturday into Sunday night. A cold front will sweep across the area on Monday, bringing a return to dry weather and VFR conditions for early next week. && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Danco/10/MWS AVIATION...Danco