Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 190523 AFDRNK Area Forecast Discussion National Weather Service Blacksburg VA 123 AM EDT Tue Sep 19 2017 .SYNOPSIS... High pressure will remain over the region this week resulting in mainly dry and mild weather during the next few days. Jose should track north, off the east coast today through Tuesday, before sliding just east of New England on Wednesday. && .NEAR TERM /THROUGH TODAY/... As of 250 PM EDT Monday... An upper-level ridge will remain over the Eastern United States this afternoon into Tuesday. Surface high pressure will control our weather into Tuesday. At 15 UTC, Hurricane Jose was located near 33.9 North and 71.1 West. Jose is moving toward the north near 9 mph and will continue this motion trough Tuesday. On the forecast track, the center of Jose is forecast to pass well offshore of the Outer Banks of North Carolina this evening, pass well east of the Delmarva peninsula tonight and Tuesday. A blend 12z GFS, 12z NAM, 12z ECMWF, 12z UKMET and 12z Canadian is reasonably close to the 15Z NHC Track for Jose. See latest NHC advisory for more information. Any shallow afternoon convection will diminish quickly with the loss of solar heating this evening. Strato-cu will linger during the evening before better subsidence starts to result in clearing overnight. The combination of low level moisture and light winds will result in fog and stratus especially in the western valleys overnight. The coverage of fog will be less in the east with more mixing expected. Low temperatures tonight will range from around 50 in the cooler mountain valleys to the lower 60s in the piedmont. The upper ridge will amplified Tuesday as a closed low digs into the northwest. Low level convergence, orographic lift and heating may generate some isolated shallow convection Tuesday afternoon. High temperatures will vary from the lower 70s in the mountains to the mid 80s in the Piedmont. && .SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/... As of 330 PM EDT Monday... The forecast area will remain sandwiched between tropical activity to the east and first signs of winter in the west with little significant weather in our neighborhood. Jose is forecast to be either a Category 1 hurricane of a strong tropical storm by tomorrow evening and continuing to move north toward New York and New England. Effects locally will be nil except for some subsidence along the western periphery. That may be offset somewhat by weak shortwave energy moving through the Ohio Valley and generating some clouds mainly across the mountains Tuesday night into Wednesday, Precipitation chances will be slight with widely scattered showers and mainly confined to the mountains in association with differential heating due to terrain. Meanwhile a strong upper trough over western Canada will be digging southward into the Pacific northwest and northern Rockies during this period helping to amplify the ridge building across the eastern CONUS. 550 mb heights will be rising to near 590 dm across the Mid- Mississippi Valley by late Thursday and through the weekend with unseasonable warmth pushing eastward. Highs Wed/Thu will run upper 70s west to mid-80s east with lows upper 50s to mid-60s, also well above normal. && .LONG TERM /FRIDAY THROUGH MONDAY/... As of 330 PM EDT Monday... Upper ridge becomes even more dominant in the extended period with a large a dome of high pressure covering the eastern CONUS and extending north into southern Canada right through the weekend. The upper low out west digs even further south into the Great Basin as short-wave energy continues to drop into the long-wave trough. At the same time whatever is left of Jose may be lingering in the western Atlantic with models continuing to struggle with how blocking to the north may affect future movements. At the same time tropical system Maria, likely still a hurricane, will be entering the picture but still well off the southeast coast. Temperatures thought the extended period will remain at about 5F to 10F above mid- to late September climatology and chances for significant precipitation will remain low beneath the strong and persistent ridge. && .AVIATION /05Z TUESDAY THROUGH SATURDAY/...
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As of 115 AM EDT Tuesday... Bands of low clouds remain mostly along and west of the Blue Ridge late tonight associated with onshore flow and spreading out of residual cumulus from this afternoon. This likely to produce areas of MVFR cigs over the next few hours before diminishing late as the flow starts to turn more north/northwest toward daybreak. Degree of clearing the key for another round of widespread dense fog across the valleys by morning as appears a little more of a gradient out east may preclude to just patchy fog there. Since clouds again look slow to go, have delayed the onset of most fog mountains with more in the way of MVFR developing a couple hours prior to dawn followed by local IFR/LIFR through sunrise. Given a bit more uncertainty plan to include mostly TEMPO groups for the lower cigs/vsbys west while including more MVFR nature in patchy fog east. Some guidance even showing more of a MVFR strato-cu layer expanding overnight before lowering to stratus/fog but iffy. Fog/stratus should burn off around 14z/10A Tuesday, with all sites VFR going into the afternoon under a SCT-BKN cumulus field similar to the past few days. A few isolated showers may develop late in the afternoon, but none should deter flight plans. A weak upper disturbance approaches from the west Tuesday evening which could bring more clouds and added showers and even an isolated storm to far western sections early Tuesday night. Otherwise expecting another round of fog/stratus to redevelop late once any shallow convection ends and clouds diminish by daybreak Wednesday. Extended Aviation Discussion... Overall persistence forecast to prevail for the rest of the upcoming week into the weekend with strengthening high pressure remaining in place between exiting Jose offshore and a weak cold front approaching from the west. This should maintain good flying weather outside of early morning fog/stratus through late next week, with only isolated diurnal showers possible mainly Wednesday and Thursday afternoons as upper level energy slides across.
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&& .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...JH NEAR TERM...KK SHORT TERM...PC LONG TERM...PC AVIATION...JH/KK/RCS

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