Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 170708 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 307 AM EDT MON OCT 17 2016 .SYNOPSIS... Surface high pressure will begin to move offshore today with southerly return flow bringing warm and dry conditions to the area for the next couple of days. && .NEAR TERM /THROUGH TONIGHT/...
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As of 305 AM Monday... Fog will be the forecast problem of the day going into the rest of the morning hours as some locations are starting to register MVFR and even some IFR visibilities. It has not been as quick to develop as yesterday so we will see how prevalent it actually is but models suggest at least the eastern half of the area could see some LIFR visibilities with MVFR likely to be the lowest in the west. Warming trend begins in earnest today as the surface high pressure slips offshore and southerly return flow overtakes the area. This will drive high temperatures up to near 80 degrees for the first time in a while which is 5-10 degrees above normal depending upon location. Mostly clear skies and light winds for much of the day. Low temperatures tonight warmer as well, in the upper 50s to near 60 degrees. A chance for fog/low stratus will be possible during the early morning hours on Tuesday morning.
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As of 305 AM Monday... Increased return flow around the back side of the surface high will bring thickness values up to around 1400 meters and this is suggestive of high temperatures in the low to mid 80s for Thursday afternoon. Another dry day is expected with partly cloudy to mostly clear skies. Low temperatures once again near 60 degrees on Tuesday night into Wednesday morning. A chance for fog/low stratus will once again be possible on early Wednesday morning.
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&& .LONG TERM /Wednesday through Sunday/... As of 300 AM Monday... Wed/Wed night: Bermuda high pressure at the surface extending westward into the Carolinas will be capped by a mid level anticyclone, resulting in deep (850-300 mb) warming and subsidence. Apart from patchy early-morning fog, skies should be generally sunny, with well above normal temps -- highs in the low to mid 80s and lows in the lower 60s -- as thicknesses are expected to be around 30-35 m above climo. Thu-Sun: The mid level ridge gives way to a narrow amplifying trough over the eastern third of the CONUS late in the week. The strengthening SSW steering flow east of the approaching trough will help draw broad low pressure over/east of Cuba/Bahamas northward, potentially as a tropical or subtropical feature, but in general the latest model solutions keep this offshore with little to no impact on NC`s weather. Regarding the approaching longwave trough, the 12z/16 ECMWF ensemble mean is a bit slower than the corresponding operational EC, which is more progressive and a bit less amplified than the GFS/GEFS. The operational GFS, which is very slow and deep and closes off a low over the FL panhandle Sat, is slower and deeper than the GEFS mean. With the EC ensemble and GEFS mean solutions fairly close, it seems prudent to go with these to time the corresponding surface frontal passage. Thicknesses remain warm ahead of the front Thu, so despite increased cloud cover, expect highs to still be in the lower 80s, with perhaps some mid 80s, and lows in the lower 60s again Thu night. Thicknesses dip down to just slightly above normal Fri, favoring highs in the 70-77 range west to east, then the more substantially cooler air arrives Sat with highs around 70, followed by a degree or two warmer Sun as modified high pressure builds in post-front from the SW. Rainfall amounts appear to be quite small with this front, given a limited opportunity for deep moisture return as higher PW values hold down over FL or near the offshore low track. Will keep a chance of showers Fri, just barely above climatology, falling off to slight chances Fri night/Sat to account for unsettled weather with the mid level trough passage. Clearing Sun with dry weather. -GIH && .AVIATION /06Z MONDAY THROUGH FRIDAY/... As of 130 AM Monday... 24 Hour TAF period: Fog will most likely be the forecast problem of the day with the latest run of the HRRR model favoring fog at eastern terminals and possibly at KRDU as well. For now have included TEMPO fog in the TAFs until we see how this develops over the next couple of hours. Otherwise VFR conditions should prevail once fog burns off later this morning. Long term: VFR conditions are largely expected through Friday or so when the next frontal system will approach from the west and bring a chance for sub-VFR aviation conditions. && .HYDROLOGY... As of 300 AM Monday... Moderate river flooding continues on the lower reaches of the Neuse and Tar rivers, with levels continuing to fall today. Minor flooding is expected for several days on the Roanoke River at Roanoke Rapids and Scotland Neck, due to upstream lake releases. For details, see && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Ellis NEAR TERM...Ellis SHORT TERM...Ellis LONG TERM...Hartfield AVIATION...Ellis HYDROLOGY...RAH is the U.S. government's official web portal to all federal, state and local government web resources and services.