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fxus61 krnk 251108 
afdrnk

Area forecast discussion
National Weather Service Blacksburg Virginia
708 am EDT Tue Jul 25 2017

Synopsis...
a weak cold front will stretch the NC west into Tennessee
today then gets pushed further south tonight by high pressure
building in from the northeast. Another cold front approaches
from the northwest Thursday into Friday exiting to our southeast
by Saturday morning.

&&

Near term /through tonight/...
as of 320 am EDT Tuesday...

Have a little fog/low clouds banked up across southern WV into the
mountain Empire where an inverted sfc trough lingers.
Expect these clouds/fog to erode after 8-10am.

High pressure will bring drier airmass/dewpoints to much of the
region today, with models showing deeper moisture shunted south of
our forecast area. Still enough of a gradient plus some return flow
and inverted trough along the southern Appalachians to maybe
generate isolated storms across the NC high country possibly moving
into the NC foothills this afternoon.



Otherwise enough subsidence for overall mostly sunny skies with
highs low/mid 80s mountains to upper 80s to around 90 east of the
Blue Ridge.



Any convection weakens and shifts out of our ares this evening with
skies staying generally clear. High pressure will be over New
England late Tuesday night so some return flow may still generate
lower stratus/fog along the southern Appalachians, but overall
confidence is low and another day of drying should limit this. Lows
running close to normal with upper 50s to lower 60s mountains, to
mid to upper 60s east of the Blue Ridge, but including Roanoke-
Lexington.

&&

Short term /Wednesday through Thursday night/...
as of 330 am EDT Tuesday...

High pressure over New York Wednesday morning will slide east in the
Atlantic Ocean Wednesday night into Thursday. Some weak orographic
lift may combine with solar heating to create isolated to scattered
diurnal showers and thunderstorms mainly along the southern Blue
Ridge. High temperatures Wednesday will range from the the mid 70s
in the mountains to the mid 80s in the Piedmont. Any convection
will taper off quickly Wednesday evening with loss of solar heating.
Under partly cloudy skies, low temperatures Wednesday night will
vary from around 60 degrees in the west to near 70 degrees in the
east. Low pressure with a trailing cold front will move east across
the Ohio Valley Thursday into Thursday night. The timing looks a
little faster than yesterday. Thus, increased pops on Thursday and
bring likely into the western mountains Thursday night. High
temperatures on Thursday will climb to around 80 degrees in the
mountains to about 90 degrees in the Piedmont. Storm Prediction Center has placed most
of the forecast area in a slight risk for severe weather Thursday
afternoon into Thursday evening. The main threat is for fast moving
bands with damaging winds. Also, any thunderstorm could produce
locally heavy rains. With clouds and rain, low temperatures
Thursday night will generally be in the mid 60s in the mountains to
the lower 70s in the Piedmont.

&&

Long term /Friday through Monday/...
as of 1245 PM EDT Monday...

Upper pattern amplifies starting on Friday with the upper ridge over
the western United States slightly retrograding and a trof digging
in the east. An upper low may eventually close off somewhere over
the Tennessee Valley or mid Atlantic region by Sunday or Monday.
This closed low solution was not supported by a majority of the
extended guidance. Probability of showers and thunderstorms will
increase on Friday and Saturday with some vorticity advection and
lowering heights. Air mass ahead of the trough stays in the +16 to
+20 range for temperatures at 850mb and will be a little cooler on
Sunday and Monday.

&&

Aviation /11z Tuesday through Saturday/...
as of 702 am EDT Tuesday...

Only area with sub-VFR conditions is blf and cigs are starting
to rise to MVFR. Should be VFR by 14z, with all sites staying
VFR through the period thanks to high pressure working southward
from the Great Lakes into New York. Any storms this afternoon
will be isolated and stay confined to the mountains south of
hlx-vji. Winds are going to be light, from the northwest most of
the period.

Fog threat late tonight expected to be light, so kept it out of
the tafs for now, with best chance of fog in the typical spots
like lwb. If enough of an east wind arrives, fog forming over
the Greenbrier River could push into lwb after 09z.

Aviation extended discussion...

Should stay VFR under high pressure into Wednesday though some
sct-bkn VFR cigs possible in the mountains (blf-lwb-bcb).

Should start to see front approaching with better threat of
showers/thunderstorms Thursday into Friday. Outside of storms
expect VFR conditions, with possible late night fog by Friday
morning.

Saturday looks drier with northwest flow, but could see
lingering low end VFR/high end MVFR ceilings in southeast WV.

&&

Equipment...
as of 345 am EDT Tuesday...

The temperature sensor on the observing equipment at Lynchburg
has failed, therefore no temperature data will be available
until technicians can replace the defective part later this
week.

&&

Rnk watches/warnings/advisories...
Virginia...none.
NC...none.
WV...none.

&&

$$
Synopsis...jh/wp
near term...wp

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