Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 271722 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA 122 PM EDT Thu Oct 27 2016 .SYNOPSIS... A weak cold front will approach the region from the west this morning before passing across the area later today into this evening. High pressure follows the front Friday bringing a return to drier and milder weather into Saturday. Another weak cold front will dip south through the Mid-Atlantic region later Sunday into Sunday night. && .NEAR TERM /THROUGH TONIGHT/... As of 300 AM EDT Thursday... Surface wave passing to the north will gradually propel a weak cold front into the mountains later this afternoon and across the Blue Ridge this evening. Moisture ahead of the boundary remains quite limited with dewpoints in the 30s/40s under westerly flow aloft. This again spells concern for coverage of showers with the front later today as best dynamics pass north while much of any initial lift will go to basically moisten the column. Models remain quite limited in producing much QPF outside of the far north/northwest with the GFS wetter with a pre- frontal convergence axis this afternoon before the actual front arrives this evening. This tied to a stronger lead shortwave rounding the base of the upper trough which looks overdone. Latest ECMWF on the other hand quite spotty with showers in having only a few hundredths mainly east of I-81 and a tenth or two to the west. However despite limited deep return moisture with only subtle backing seen aloft today, lapse rates look rather steep and with progged theta-e ridging and weak diffluence aloft, still appears a couple bands of broken showers possible. This mainly within a possible pre- frontal band over the west that will attempt to shift into southeast sections late, and with the actual front crossing the western ridges by early evening. Isolated thunder cant be totally ruled out mainly far north per upper support, and over the far south where guidance shows some weak late day instability, but quite iffy given limited moisture recovery at this point. Thus keeping pops mainly chance while cutting back on thunder and allowing some sunny breaks espcly east this morning and perhaps at times over the west if showers are slower to develop. Also leaned a little more toward the milder Met mos today given warmth aloft and westerly flow which with some breaks could allow readings to jump well into the 60s to near 70 southeast. Front should finally clear the area overnight allowing drying aloft to kick in as northwest flow aloft increases. This should shut off most lingering shower chances during the evening with downslope clearing taking shape out east. However low level moisture within the northwest trajectory likely to aid low clouds and possibly spotty drizzle western slopes after midnight with low clouds likely spilling out toward the Blue Ridge overnight. Thus becoming mostly clear east to partly cloudy Blue Ridge to remaining mainly cloudy far west. Cool advection bleeding into the west should allow lows to drop off into the 40s west of the Blue Ridge with overall low/mid 50s east given best cooling aloft to the north and west. && .SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/... As of 330 AM EDT Thursday... After a vigorous short wave exits New England on Friday, the upper level pattern will trend to a progressive quasi-zonal regime through the weekend. Anything resembling cold air will remain bottled up to our north and with high pressure at the surface taking up a position over the southeast we will have a steady warming trend with temperatures well above normal through the weekend. By Sunday a low will be sliding by to our north and slowly pushing a weak frontal boundary into the region. This may bring a shower to the far north from Greenbrier county WV through the Alleghany Highlands and down the western slopes of the Appalachians later on Sunday into Sunday night, but any precipitation looks to be meager and the majority of the area will see no precipitation at all. It also looks to be a bit breezy mainly Saturday night and Sunday. High temperatures on Friday will generally be in the upper 60s/lower 70s east of the Blue Ridge to low/mid 60s west. However by Sunday highs will be close to 80 for some locations east of the Ridge with low/mid 70s west, which will be a solid 10 degrees above normal. && .LONG TERM /MONDAY THROUGH WEDNESDAY/... As of 300 PM EDT Wednesday... Above normal temperatures will continue into the medium range with Southeast ridging. Several shortwaves will rotate across the northern Tier of the CONUS in the fast upper flow. High pressure will build south into our region for Monday into Wednesday. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/... As of 125 PM EDT Thursday... Some showers and cloud cover is in place over the region associated with an upper level disturbance. A weak cold front is also expected to cross the area during the TAF period. Winds are expected to be relatively light with the exception of some gusts at BLF. For the short term, conditions will remain VFR with some low to mid level cigs. Areas east of the mountains can expect to remain VFR through the forecast. Those locations at elevation can expect at the minimum MVFR conditions overnight. BLF should see a lower cloud deck moving overhead this evening which will cause vis restrictions. This will persist until after sunrise until enough heating takes place to burn the deck off. Some guidance suggests that visibility at LWB could become IFR late tonight, however, enough uncertainty exists as to just as far the temp will drop this evening that it was left as a tempo group. Any chances for fog will diminish shortly after sunrise. Afterward, high pressure will dominate the region and VFR conditions will prevail. Extended aviation discussion... VFR conditions should persist through the next several days as high pressure becomes the dominant feature for the region. Some possibilities for MVFR and perhaps a shower exist for Sunday ahead of another weak front, but models seem to be in disagreement with placement and this feature may very well miss the region to the north. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...JH NEAR TERM...JH SHORT TERM...MBS LONG TERM...KK/MBS AVIATION...JH/JR is the U.S. government's official web portal to all federal, state and local government web resources and services.