Area Forecast Discussion
Issued by NWS Blacksburg, VA

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FXUS61 KRNK 171735

Area Forecast Discussion
National Weather Service Blacksburg VA
135 PM EDT Sun Sep 17 2017

High pressure will remain over the region into early next week
resulting in mainly dry and mild weather over the next few
days. Jose should track north, off the east coast Monday and
Tuesday, before sliding just east of New England on Wednesday.


As of 910 AM EDT Sunday...

Low level clouds and fog are lifting this morning. Made some
minor adjustments in temperatures and dew points for this
morning into this afternoon, shaping with surface obs, trends
and Glamp. Forecasted high temperatures look good with readings
in the upper 60s in the northwest to the mid 80s in the
piedmont. There appears to be enough lift to support the mention
of isolated shallow convection, especially across the north.
Have a good Sunday !

As of 230 AM EDT Sunday...

Overall forecast remains similar to that of Saturday with the region
under surface high pressure while having a weakness aloft to the
north between upper ridging both offshore and to the southwest. This
while within a weak low level convergence pattern per more northeast
flow east of the mountains and weak west/northwest flow out west.
Short term guidance again attempts to produce enough lift within
this regime to result in isolated shallow convection this afternoon
beneath dry air aloft. Again appears the best shot at showers will
be just north of the region, closer to the core of the weak wave
aloft, and perhaps northeast sections given better northeast
flow under this feature aloft. Latest ensemble Cams and the
HRRR show this along the northern Blue Ridge early this
afternoon with very spotty nature coverage elsewhere mountains
at best. Thus will keep in a mention and adjust coverage a bit
but still no more than 20 pops for now.

Otherwise will again see areas of mid clouds along with patchy
fog early before heating of low level moisture helps trend
toward developing cumulus during this afternoon. Should again
be another very warm afternoon per slight warming aloft and
strong heating within rather light overall easterly flow.
Appears can add on a degree or two to highs from Saturday with
low/mid 80s east and 75-80 west.

May again see residual late day clouds spread out into a leftover
trapped strato-cu layer this evening before clearing out overnight
as any isolated showers quickly fade with loss of heating. With
dewpoints still quite moist to the northwest of Jose, expect
another round of at least patchy fog espcly west where winds
should be lighter. Lows again similar to the past few overnights
with most in the 58-65 range except slightly cooler valleys.


As of 220 AM EDT Sunday...

The overall synoptic pattern will continue to feature an eastern
ridge/western trof through midweek with a subtle influence from
hurricane Jose as it moves northward just off the coast. Circulation
around Jose will push some low level moisture into the region on
northeasterly winds Monday, with enhanced convergence and orographic
affects from the Blue Ridge westward yielding a chance of showers. As
Jose pulls off to the northeast on Tuesday, winds will become
northwesterly and allow some weak shortwave energy upstream to bring
just a slight chance for an isolated shower west of the Ridge. Better
energy will stream in our direction Wednesday with a chance for showers
and thunderstorms west of the Ridge during the afternoon.

With no fronts moving through to change the airmass, expect little
change in temperatures for the next several days. Expect highs
generally in the low to mid 80s east of the Blue Ridge with mid to
upper 70s west. Lows will be in the low to mid 60s east to middle and
upper 50s west with cooler readings in the valleys.


As of 250 PM EDT Saturday...

An upper level trough will move over the east coast states Thursday and
Thursday night. Underneath this trough is a weak surface high that is
expected to wedge south into the Carolinas Thursday night and stay
through next weekend. Warm air gliding over this wedge and increasing
isentropic lift may keep the skies overcast with light rain or drizzle
falling through the day Friday. An upper level ridge moves over the
wedge by Saturday which will help remove moisture and lift over the
area. This upper level ridge will likely play a role in the track of
the next tropical system approaching the southeast US.

Temperatures will remain warmer than normal through the workweek.
Temperatures fall back towards normal over the weekend. Normals for
late September range from the mid 70s to lower 80s.


As of 135 PM EDT Sunday...

SCT-BKN VFR clouds expected this afternoon into tonight. An
isolated shower could form this afternoon across northern
portions of the forecast area.

Expect may see another round of high end strato-cu or mid deck
canopy redevelop overnight as moisture is trapped beneath the
inversion aloft. This may again produce a round of VFR cigs with
added sub-VFR conditions with fog/stratus in the valleys. Any
low clouds and fog should lift quickly by 13z Monday with VFR
conditions returning. Isolated MVFR showers may be possible in
the mountains Monday Afternoon.

Winds will remain light and variable for the TAF period.

High confidence on ceilings, visibilities and winds during the
taf period.

Extended Aviation Discussion...

Overall persistence forecast to prevail for much of next week
with strengthening high pressure remaining in place between Jose
offshore and weak cold fronts 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 each afternoon.




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