Area Forecast Discussion
Issued by NWS Blacksburg, VA-- Highlight Changed Discussion --
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FXUS61 KRNK 211402
Area Forecast Discussion
National Weather Service Blacksburg VA
1002 AM EDT Tue Mar 21 2017
A front extended from North Carolina and Kentucky to across
southeast Missouri this morning. This front will move south today
and tonight and by late Wednesday will trail across the Gulf Coast
states. A large high pressure system builds in over the eastern
United Stated behind this front for Wednesday and Thursday. On
Friday and Saturday a low pressure system will track out of the
Central Plains and into the Ohio Valley.
.NEAR TERM /THROUGH TONIGHT/...
As of 1002 AM EDT Tuesday...Increased sky cover along and west
of the Blue Ridge per recent visible satellite trends and BUFKIT
RH profiles which are clearly higher there than in the
foothills and Piedmont areas. That will lead to more variable
cloud cover through at least the early afternoon, highest for
western areas and least for southern and eastern counties.
Upstream observations indicate a lot of stratus, mist and/or
light ground fog evident across central and western WV. While it
is not clear that fog will advect that far east into our
southeastern West Virginia counties, it probably will heavily
curb temperature rise there. Also used some of the raw guidance
- primarily the most recent RAP hourly temperatures - which
captures the slower warm-up there the best. In the eastern
Piedmont and northern part of North Carolina, temperatures stand
to be significantly warmer. Highs in the VA/NC Piedmont and
foothills areas should reach the lower 70s, looking at mid/upper
60s along and just west of the Blue Ridge, to the mid 50s to
near 60 for much of the Mountain Empire of Virginia into
southeast West Virginia.
Prospects for convection still appear to be mainly confined to
our southeastern third of counties, across the Virginia
Southside, northern North Carolina and into the North Carolina
High Country later today and into tonight. However, reviewing
recent trend in HRRR reveals idea that stronger convection
would lie along and south of a line from Bristol TN to
Asheville NC. More details to come later today.
Previous near-term discussion issued at 430 AM follows...
Isolated showers are expected this morning with the best coverage of
precipitation north of a line from Lewisburg to Lynchburg, similar
the latest HRRR forecasts. Scattered to numerous showers and
thunderstorms will develop afternoon along a south of a cold
front. This will mainly be over southern Virginia and northern
North Carolina. By this evening the front will extend from the
Outer Banks to central Arkansas.
Winds turn to the north and northwest behind the front with the best
push of colder and drier air advecting south after 06Z/2AM. Will
have a dry forecast for late tonight in all but northern North
Enough breaks in the high clouds east of the Blue Ridge this morning
that there will be good heating. Plus winds will be in a downslope
direction so will stay on the warmer side of guidance for afternoon
highs in the east. How long low clouds remain over the west will
have a large influence on maximum temperatures. There will be a
north to south gradient tonight in minimum temperatures from the
lower 20s in part of southeast West Virginia to the mid to upper 40s
in the North Carolina piedmont.
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
As of 300 AM EDT Tuesday...
High pressure over the Great lakes will build south into our region
Wednesday. The high center will build eastward and reach
Pennsylvania by Wednesday night and then slide southeast to the
Virginia coast by Thursday afternoon. A dramatic change in
temperatures is expected Wednesday as cold air pushes south into our
region. High temperatures on Wednesday will range from the upper 30s
in northwest Greenbrier county to around 60 degrees along the
southern Blue Ridge. Cold air Wednesday night will send temperatures
down to around 20 degrees in the northern mountains to near 30
degrees in the Piedmont. Under sunshine, High temperatures Thursday
will warm to the lower 40s in the west to the lower 50s in the east.
Cool wedge of high pressure will move off the Virginia coast
Thursday night. Low temperatures will moderate Thursday night with
readings generally from the the upper 20s to lower 30s.
.LONG TERM /FRIDAY THROUGH MONDAY/...
As of 300 AM EDT Tuesday...
As the high center tracks east into the Atlantic ocean, a warm front
will push moisture over the mountains Friday and Friday night. With
the ECMWF and GFS pushing some moisture into our Northwest,
increased clouds and allowed for a slight chance for showers.
Elsewhere, a bubble high will likely remain east of the Blue Ridge
and over the foothills and piedmont counties into Friday night. Kept
temperatures on the cooler side with readings Friday from the lower
50s in the west to the upper 50s to near 60 degrees in the east. It
should be dry Friday night with low temperatures generally from
around 40 degrees to the upper 40s.
As a cold front approaches from the west, the wedge should be
completely erode out of the region by Saturday afternoon with
temperatures warming into the mid 60s to lower 70s across the
forecast area. An area of low pressure is expected to track from the
Midwest Saturday night towards the Ohio Valley Sunday. A cold front
and its associated convection will move through our area Sunday and
Sunday night. The track of the system and timing of prefrontal
convection into the region will be the biggest influence on the
potential for strong to severe storms. In the wake of the cold
front, drier air should push into our region for Monday.
.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
As of 720 AM EDT Tuesday...
Front extending from northern Arkansas to western Virginia will
be the focus for showers and thunderstorms today. Storms that
develop over Tennessee will move east into North Carolina this
afternoon and evening. The front will continue to move south
overnight and will be well into central and southern North
Carolina by Wednesday morning.
Northwest wind will combine with low level moisture to generate
lower clouds this morning. Ceilings have been dropping but have
not yet reached MVFR. MVFR ceilings are possible at KLWB and
KBLF through 14Z/10AM. Sites east of the Blue Ridge should
become VFR this morning.
MVFR fog in the NRV and locations that had rain overnight will
dissipate by 14Z/10AM.
Extended Aviation Discussion...
High pressure builds in for Wednesday which should improve
ceilings back to VFR.
By Thursday the high will wedge in from the northeast, so will
remain mainly VFR. It is possible that residual lower ceilings
may get trapped especially along and east of the Blue Ridge
Wednesday night into Thursday, resulting in possible MVFR
ceilings. Dry and warmer weather is expected on Friday.