Area Forecast Discussion
Issued by NWS Blacksburg, VA

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FXUS61 KRNK 230552

Area Forecast Discussion
National Weather Service Blacksburg VA
152 AM EDT Sat Sep 23 2017

High pressure over the eastern United States will continue to
bring warm and dry weather to the region this weekend through
the first part of next week.


As of 840 PM EDT Friday...

Isolated convection has again faded out with loss of heating
after a very warm afternoon for late September. This should
leave the region with quiet weather under weak surface high
pressure overnight. However will continue to see some inland
push of mid/high clouds from the northeast that could result in
cloudy periods espcly north/east early on. Think the residual
canopy including some strato-cu should fade/thin later tonight
as much drier air aloft advects in under stronger mid level
ridging that looks to build in late. Otherwise will again see
patchy to areas of fog where earlier heavy downpours occurred as
well as in the valleys pending late clearing. Clouds may also
tend to keep lows up more in the 60-65 range unless clearing can
coincide with a slight drop in dewpoints toward dawn which
would result in a few cooler 50s espcly west.

Previous discussion as of 300 PM EDT Friday...

No change in the general synoptic pattern as a large ridge of
high pressure dominates the eastern US while tropical systems
over the Atlantic remain too far offshore to impact our weather.
Combination of diurnal instability, orographic effects, and some
weak short wave energy will keep a chance/slight chance for
showers/storms in the forecast from the southern Blue Ridge and
portions of the NRV south into the mountains of NC. Any
precipitation will fade quickly by early this evening with dry
conditions for the overnight period. Expect another round of
patchy fog/stratus development primarily west of the Blue
Ridge. Any fog/low clouds will burn off early Saturday, followed
by pleasant weather for the start of the weekend.

Temperatures will be similar to previous days. Expect lows
tonight in the lower 60s east of the Blue Ridge with mid
50s/around 60 to the west and some cooler readings in the
valleys. Highs Saturday will be in the mid/upper 80s east to
lower 80s west.


As of 250 PM EDT Friday...

A Rather quiet weather pattern through this period, with high
pressure firmly in place near the mason dixon line, and continuing
to build South along the central appalachians. Hurricane Maria is
expected to drift North off of the southeast US coast, but likely
remain far enough out to sea to limit impacts in our area through
Monday. This setup would allow mostly sunny and dry conditions to
remain in place. High Temperatures should remain steadily 5 to 10
degrees above normal during the period, topping out in the mid to
upper 80s east of the Blue Ridge, with upper 70s and low 80s
prevalent across the higher elevations. Low temperatures would fall
into the 50s and 60s, with patchy fog possible each morning,
especially in the mountain valleys.


As of 250 PM EDT Friday...

High pressure will begin to progress north and east into the New
England states by Tuesday, as Maria begins to slow and wobble off of
the Mid Atlantic Seaboard. This will allow surface winds to shift to
out of the East/Northeast, allowing low level atlantic moisture to
build across the area Wednesday and Thursday. With subsidence still
in place, don`t expect much in the way of shower activity, but cloud
cover as a whole should increase, especially for those East of the
Blue Ridge. A Persistence forecast trend in temperatures
will continue through this time period.

A cold front approaches from the north and west on Thursday,
bringing the possibility of isolated to scattered showers across the
area. Timing of the front, at least in the eyes of the GFS, doesn`t
look favorable for significant shower coverage or intensity, but it
should be enough to push the remnants of Maria far enough off shore
to break us free from the easterly flow. Drier and more seasonable
conditions should follow the front, and continue into the weekend.


As of 145 AM EDT Saturday...

Satellite pictures showed mid and high clouds from Maryland into
eastern Tennessee early this morning. MVFR fog was develop south
of this cloud cover over central and southern Virginia and
northern North Carolina. Similar to past few mornings,
expecting the visibility at KBCB to drop to LIFR levels around
sunrise. KBLF and KDAN may also lower to LIFR values but
confidence not as high for those sites. KLWB may have too much
cloud cover for more than a short period of LIFR prior to

Strong high pressure building in from the north on Saturday
should result in widespread VFR once any low clouds/fog fade by
mid morning. Winds should continue mostly easterly at 5-12 kts
overall into Saturday afternoon.

Extended Aviation Discussion...

Overall persistence forecast Sunday into early next week as
strong high pressure aloft builds in from the northwest keeping
tropical moisture offshore. This should also maintain good
flying conditions along with mostly dry weather, outside of any
late night/early morning fog from Sunday through Wednesday.




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