Area Forecast Discussion
Issued by NWS Blacksburg, VA

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FXUS61 KRNK 291724

Area Forecast Discussion
National Weather Service Blacksburg VA
124 PM EDT Mon Aug 29 2016

A weak frontal boundary slides to the mid-Atlantic coast by
Tuesday morning, while a tropical depression closes in toward the
Outer Banks of North Carolina. The front then steers the tropical
system off the northeast midweek. A stronger front arrives


As 0f 847 AM EDT Monday...

Made some adjustments in cloud cover for this morning. In general
increase clouds in the southeast portions of forecast area.
Adjusted temperatures and dew points with sfc obs and trends for
late morning into this afternoon, then shaped towards the lav
guidance for this afternoon. The Hiresw-arw east, RNK WRFARW and
HRRR support isolated to scattered convection in the northwest
portions of the forecast area, mainly after 19z. More changes
later this morning....

As of 238 AM EDT Monday...

Surface high situated from the Ohio Valley into the Mid-Atlantic to
stay in place today. Meanwhile, tropical depression eight resides
east of the Outer Banks. Models show this system shifting west-
northwest toward Cape Hatteras by 12z Tuesday. Actually could see
some mid and high clouds from it today in the eastern half of the
forecast area. Pattern seems similar to yesterday over the mountains
and models favor an area of convergence into Southeast WV and far
Southwest Virginia this afternoon, so kept chance pops there with
slight chance into portions of the New River Valley.

With a light northeast to east wind at the surface with upper ridge
overhead still expect a warmer than normal day but humidity should
not be stifling. Highs will range from around 90 in the Piedmont, to
mid to upper 80s in the west, but cooler on the ridges. Models
subside any convection this evening but GFS showing some increase in
8h moisture overnight. This may seem overdone but could see some
strato-cu/stratus somewhat across the Blue Ridge and east late. Will
mainly stay mostly clear to partly cloudy but something to watch.
Low temperatures will be in the 60s most areas.


As of 145 AM EDT Monday...

A weak frontal boundary will enter the region on Tuesday and stall
through Wednesday fueled partly by weak shortwave troughs moving
eastward along the U.S./Canadian border. The presence of the front
will help be the focus for isolated to scattered showers across the
region. A more substantial cold front will enter the area on
Thursday and be southeast of the region by Thursday night as a
strong longwave trough develops across the eastern U.S.

Temperatures during this portion of the forecast will trend slightly
cooler each day. However, readings will still average about five
degrees above normal for highs on Tuesday and Wednesday with lows
both of those days close to ten degrees above normal. Thursday will
be slightly cooler with highs around normal and lows about five
degrees above normal.


As of 400 PM EDT Sunday...

Models continue to advertise a much sharper upper level long wave
trough developing from Ontario Canada to the Mid Atlantic by the
end of the week. A transition to a cooler drier airmass expected by
Friday. In spite of the cooling and drying progged for our CWA,
the tropics are forecast to be busy, with potential impacts to
Florida and nearby states. The upper trough which sets up over the
eastern US will likely play a large role in steering the near
CONUS tropical systems during this period. Please refer to The
National Hurricane Center for the latest information


As of 124 PM EDT Monday...

Surface high pressure situated from the Ohio Valley into the Mid-
Atlantic will remain in place this afternoon into tonight. The
combination of heating and low level convergence will generate
isolated to scattered MVFR convection, mainly in the northwest
portion of forecast area. The taf site with the best chance for
convection is KLWB. Any convection that develops will tape off
quickly this evening into tonight. Light winds with low level
moisture will create areas of low clouds and fog tonight into
Tuesday morning.  VLIFR conditions are possible at KLWB. While the
valley like KBCB may see MVFR fog.

Morning fog will burn off by 14z with VFR expected at all sites
Tuesday morning. Isolated diurnally driven MVFR convection will be
possible Tuesday afternoon. Coverage will be limited in duration and
area, thus holding off on mention at taf sites.

Medium confidence in ceilings,visibilities and winds during the taf

Extended aviation discussion...

Another front will move into the region Wednesday into Thursday with
a better chance for MVFR/IFR showers/thunderstorms, followed by
cooler and drier air for Friday. Most of the period looks VFR at
this point, outside of the usual late night/early morning fog/low
clouds. At this time, it does not appear that any tropical systems
will impact the county warning area.




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