Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 071127 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 626 AM EST Wed Dec 7 2016 .SYNOPSIS... Weak high pressure will settle over the Carolinas today. An arctic cold front will move through the area Thursday. && .NEAR TERM /THROUGH TONIGHT/... As of 320 AM Wednesday... Broad troughiness over the Central US, associated with the mid-level low traversing eastward across southern/southeastern Canada, will shift eastward into the eastern US by late Thursday. IFR ceilings associated with the lingering wedge airmass will gradually mix out this morning as drier works into the area from the west. Continued energetic SWLY flow aloft with weak high pressure at the surface, will mean central NC will see a brief return of sunshine today. Despite neutral temp advection over the past 24 hours, this sunshine will result in warmer temperatures this afternoon. Highs 55 to 60. Clouds will begin to increase late this afternoon and through the evening with the approach of the upper trough and resultant shallow southerly moist upglide ahead of an Arctic cold front moving into the area from the west. Models have been pretty consistent in showing some isolated showers/sprinkles accompanying the front, with the front expected to approach the Triad right around daybreak Thursday. Uniform lows in the upper 30s to lower 40s. && .SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/... As of 320 AM Wednesday... Shallow moist upglide ahead of the leading edge of the Arctic intrusion spreading west to east through the area on Thursday will support a broken band of very light rain showers/or sprinkles with abrupt clearing in it`s wake owing to the strong cold dry air advection. In fact, we could see temperatures falling across the western piedmont by the afternoon. Highs ranging from lower 50s NW to upper 50s southeast. Strong CAA will continue Thursday as expansive Arctic high begins east into the region. Overnight lows in the mid 20s to upper 20s with a steady wind 7kt breeze resulting in chill values in the teens. && .LONG TERM /FRIDAY THROUGH TUESDAY/... As of 205 AM Wednesday... Expect cold/brisk conditions on Friday with highs in the upper 30s to lower 40s and a brisk NW breeze assoc/w strong cold advection as 1040 mb arctic high pressure builds eastward from the central plains toward the Appalachians in the wake of the cold frontal passage late Thu/Thu night. Expect chilly lows in the upper teens to lower 20s Sat morning as the arctic high settles over the Carolinas from the west Friday night, with highs on Sat similar to Friday albeit a few degrees warmer. Forecast confidence decreases significantly in the Sun-Tue time frame when the GFS/ECMWF differ by as much as ~24 hours with regard to the timing/evolution of the next upper wave/cold front approaching from the west. The GFS indicates a weaker, more progressive wave with an attendant cold front moving offshore Sun night. The ECMWF, however, indicates a more potent upper level wave /attendant sfc low/ and suggests the associated cold front will cross central NC Monday afternoon, exiting offshore late Monday evening into Monday night. With the above uncertainty in mind, will make little change to the prior forecast Sun-Tue. -Vincent && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... As of 0630 AM WEDNESDAY... Drier air will continue to filter into the area from the west, leading to scattering out any lingering IFR ceilings and fog across this morning with VFR conditions expected to be the rule through the afternoon. Outlook: Shallow warm-moist air advection in advance of a strong arctic cold front will result in a good chance of MVFR ceilings within a broken band of isolated showers that will move west to east the area on Thursday. && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...CBL NEAR TERM...CBL SHORT TERM...MLM LONG TERM...Vincent AVIATION...CBL is the U.S. government's official web portal to all federal, state and local government web resources and services.