Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 180709 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 309 AM EDT Wed Oct 18 2017 .SYNOPSIS... Surface high pressure over the Mid-atlantic will extend across the region into the weekend. A cold front will approach the area from the west early next week. && .NEAR TERM /THROUGH TONIGHT/... As of 245 AM Wednesday... Recent water vapor imagery shows upper-level ridging across the Mid- Atlantic along with a lingering trough axis off the Southeast coast and a short wave trough across the western Ohio Valley. The latest surface analysis shows a ridge of surface high pressure centered across western Virginia. The air mass across the Carolinas is rather dry with precipitable water values from the Tuesday evening RAOBs ranging around a third of an inch. Quiet weather is expected today with bright sunshine and perhaps a few wisps of cirrus clouds this afternoon across the west as the ridge axis slips east and a weak trough approaches. After a chilly morning, temperatures should jump 20-25 degrees between 8 and 11am this morning as the surface inversion breaks. Statistical guidance is in good agreement indicating highs in the 67 to 73 range. Scattered cirrus clouds will increase from the west overnight as the trough axis approaches from the west. In addition, low-level northeast to easterly flow combined with some weak isentropic lift will result in increasing low-level moisture and shallow weak ascent across the Coast and Coastal Plain late tonight which may result in a few areas of stratus toward daybreak. The return flow will also result in some moderation of minimums with lows tonight ranging from the upper 30s across the northern Piedmont near the VA border to the mid 40s across the southern Coastal Plain. With a moderated air mass and some clouds, the potential for patchy frost should be minimal. -Blaes && .SHORT TERM / THURSDAY THROUGH THURSDAY NIGHT/... As of 300 AM Wednesday... A quiet weather regime continues into Thursday and Thursday night as surface high pressure remains in control. A short wave trough pushes across the Carolinas on Thursday and offshore on Thursday night resulting in some transient and patchy cirrus clouds. Some shallow moisture could result in some patchy fog or stratus across the Coastal Plain toward daybreak Friday. Otherwise, skies should be generally clear. Highs on Thursday will range in the lower to mid 70s with lows Thursday night in the lower to mid 40s. -Blaes && .LONG TERM /FRIDAY THROUGH TUESDAY/...
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As of 305 AM Wednesday... Surface high pressure over the region to start the period late week, will shift offshore this weekend. Meanwhile, mid/upper level ridging will move across the region from west to east late week into the weekend. This will yield quite/dry weather during this time frame, with some increasing moisture by late Saturday into Sunday. Expect highs temps will be above normal during this period, generally ranging from the mid to upper 70s to even some lower 80s. Low temps are expected to range from the mid 40s to mid 50s during this time frame (coldest on Saturday morning). Chances for showers and possibly some thunderstorms will increase early next week as a surface cold front approaches. However, model guidance continues to show very poor run to run continuity, along with a large spread in the ensembles, with regard to the evolution of the mid/upper level flow pattern across the CONUS next week. Strength of the next system along with the timing remains in question. However, chances for some decent precip appear to be increasing for the period of early to mid next week, though which day(s) will have the highest chances is still very much in question (along with temps for the period). For now will generally go with chance pops for early next week, with both pops and temps hedging towards a bit slower frontal passage (which is more in line with the 00Z/18th GFS and 12Z/17th ECMWF and the previous forecast). Thus, will go with highs Monday in the 70s, to lower 80s and highs on Tuesday generally from 70-75.
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&& .AVIATION /07Z WEDNESDAY THROUGH SUNDAY/... As of 140 AM Wednesday... High confidence of VFR conditions through the 24-hour TAF period. Surface high pressure and weak ridging aloft will result in generally clear skies and fair weather. Light northeast to easterly surface winds will range between 4 and 8kts today with very light to calm winds expected early this morning and again tonight. Looking beyond the 24-hour TAF period, surface high pressure will persist across the region into the weekend. Some patchy stratus or fog is possible across the Coastal Plain impacting the KFAY/KRWI around and just prior to daybreak on Thursday and possibly Friday mornings. -Blaes && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...BLAES NEAR TERM...BLAES SHORT TERM...BLAES LONG TERM...BSD AVIATION...BLAES is the U.S. government's official web portal to all federal, state and local government web resources and services.