Area Forecast Discussion
Issued by NWS Blacksburg, VA-- Highlight Changed Discussion --
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FXUS61 KRNK 280147
Area Forecast Discussion
National Weather Service Blacksburg VA
847 PM EST Mon Feb 27 2017
High pressure will continue to drift east and offshore overnight.
A warm front is expected to lift northeast into the region
Tuesday, before passing to the north Tuesday night, in advance
of a strong cold front that will arrive late Wednesday. Cold
high pressure will follow the front for the end of the week.
.NEAR TERM /THROUGH TUESDAY/...
As of 840 PM EST Monday...
Weak upper disturbance currently crossing the region per vapor
loop will exit overnight leaving a warm advection pattern
aloft in place around high pressure offshore. This feature may
act to produce a few sprinkles over the north and west early on
before better mid level drying seen to the west edges east.
Some low level moisture will also gradually start to work in
across the far south/west later tonight as southwest flow
deepens, but appears too shallow with limited focus for much
added shower coverage. In addition, evening soundings remain
very dry below 700 mb which supports little rainfall overnight
excluding current sprinkles. Therefore basically removing pops
similar to latest short term solutions as appears the Nam
remains overdone, with added showers over the southeast where
will be to the north of ongoing convection attm.
Clouds remain a bit more tricky with guidance showing enough
drying for some clearing espcly mountains overnight in the wake
of the exiting impulse. This while maintaining more canopy over
the east where weak return moisture advection is expected late.
However latest satellite trends would support some breaks all
sections after midnight as brief subsidence increases. Thus have
adjusted sky cover down enough for becoming partly cloudy most
sections overnight. Low temps quite dependent upon sky cover
given lingering dry dewpoints as more breaks could allow for 30s
valleys with 40s most other locations. Since this scenario
looks on track, only making small adjusts to going forecast low
temps overnight at this point.
Previous discussion as of 330 PM EST Monday...
High pressure will continue to drift to the east this evening,
as a weak upper-level disturbance overspreads mid to upper level
clouds into the region. Weak radar echo returns show up
periodically, resulting in little to no ground-truthing
precipitation. This is made possible by a rather deep SFC to
700mb dry layer, featured well on the KROA/KGSO 12z sounding.
The cloud cover did serve a purpose though, limiting temperature
potential, especially along and west of the Blue Ridge
Mountains. Minor tweaks to the forecast made here, accounting
for cooler temperatures in the west, with warmer conditions in
the Piedmont Counties of VA/NC where the sun made a longer
Expect winds to continue responding to the slipping high
pressure center, shifting to more southerly flow Monday evening.
5 to 10 mph winds with a few periodic gusts may be possible, but
things should settle down quickly after sunset. Expect the cloud
shield to hold strong most of the overnight hours, with the
exception of portions of Southeast West Virginia who may see a
shot of drier air in the mid-levels aiding in their ability to
clear out between midnight and sunrise.
Early Tuesday, a warm front draped across northern GA into
northern SC will begin to inch its way North. Patches of light
rain is expected to spread northward along/southeast of the
Blue Ridge by mid day. Through this portion of the forecast
period, QPF will generally be just a few hundredths of an inch
at best and generally confined to areas south-east of the Blue
Ridge. Higher amounts will be possible later on Tuesday as
convergence and isentropic lift combine along the western
ridges. A few rumbles of thunder aren`t out of the question in
these areas, but conditions won`t be ideal for large scale
development this far east. Convection bleeding over from the
Ohio Valley would be the best bet for late February storm
lovers. For now, have left thunder out of the forecast, with
just isolated/scattered showers and highest accumulations west
of the Blue Ridge. Persistent cloud cover and warm conditions
will remain the top weather story in the afternoon.
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
As of 330 PM EST Monday...
Expect warm front lifting north across us late Tuesday night.
Showers will be situated mainly over the mountains in the evening
and as the warm front continues north look for drying a bit into
Wednesday still looking a bit active with cold front moving from the
Mississippi River Wed morning to the Blue Ridge by evening. Strong
wind fields with this system will lead to threat of showers and
thunderstorms with gusty to damaging winds. SPC still has our area
in a slight risk. Timing is still looking like afternoon/evening
starting by noon-2pm WV to 7-9pm piedmont.
Once the line moves across moisture dissipates quickly so limited
snow shower threat in WV Thursday morning.
Best pressure rises post frontal will be Wednesday evening and again
Thursday. At the moment seems winds should stay just below advisory
levels, but could see some stronger gusts along the Blue Ridge
Some increase in clouds late in the northwest ahead of a southeast
moving front with limited moisture late Thursday night. Will see
lows near normal.
.LONG TERM /FRIDAY THROUGH MONDAY/...
As of 330 PM EST Monday...
Secondary shot of cooler air arrives with a mainly dry front from
the northwest Friday. Appears best lift/moisture stays north across
the Shenandoah Valley, so it will be mainly low chance pops of snow
showers across the mountains of Southeast WV into the Alleghanys.
Winds should speed up behind this system Friday afternoon but 8h
wind stay under 50kts, and pressure rises are marginal, so most
gusts will be under advisory levels.
Expect high pressure overhead Saturday to provide close to normal
highs for early March ranging from the lower to mid 50s over the
area, with some 40s in the mountains.
Keeping it dry Sunday with milder temperatures as high pressure
moves southeast off the Southeast coast. A front enters the northern
tier of the U.S. the slides southeast to the Ohio Valley by Monday.
Will see warmer temperatures Sunday-Monday with shower chances
.AVIATION /01Z TUESDAY THROUGH SATURDAY/...
As of 630 PM EST Monday...
A weak upper-level disturbance producing a rather stubborn mid
to upper level cloud deck will continue to push east of the area
overnight. This will allow for a brief period of drying in the
mid levels of the atmosphere, providing relief for ceilings
prior to the arrival of a slow moving warm front approaching our
from the Carolinas. A transition from a 5K foot BKN/OVC deck to
SCT/FEW layers is expected during the overnight hours Monday
into Tuesday, especially for the northern/western airport
locations. These dry conditions should also limit any fog
development, thus allowing the continuation of VFR conditions
through at least the early morning hours Tuesday.
A warm front arrives on our southern doorstep overnight,
allowing for resaturation of the lower atmospheric levels. This
will act to once ago lower ceilings during the day on Tuesday.
Early indications have sub VFR conditions impacting KDAN/KLYH
as early as mid afternoon, with other sites following suit
rapidly. Precipitation chances also increase late in the TAF
period, but uncertainty remains on aerial coverage and
intensity. For now, have introduced VCSH, but reduction of
visibilities may be needed in future TAF forecast runs. Winds
shouldn`t be much of a factor this period, remaining sustained
below 10KTs, with only localized gusting.
Overall, medium to high confidence of VFR+ conditions through
sunrise, with uncertainty increasing with ceilings + vsbys as
the day continues on Tuesday.
Extended Aviation Discussion...
A warm front across the southeast states will lift northeast
Tuesday before passing to the north of the area on Wednesday.
An increase in low-level moisture will likely result in
MVFR cigs Tuesday evening, especially along and near the Blue
Ridge with moist southeast flow. A few light rain showers may
also accompany the front.
A cold front pushes east into the area Wednesday into Wednesday
night with potential for more widespread MVFR/IFR in showers
and thunderstorms. A west to east moving squall line with strong
to possibly severe thunderstorms, perhaps a QLCS type convective
configuration, will be possible late Wednesday into Wednesday
evening in advance of the front. Strong northwest winds along
with mountain sub-VFR in upslope low clouds and light precip
will likely follow the front for much of Thursday. Expect
downslope drying to return VFR to eastern locations by Thursday
afternoon with this trend lingering across eastern sections
through the end of the week. However another weak clipper area
of low pressure looks to track just north of the region by
Friday with possible mountain MVFR in at least upslope
cloudiness, and possible light precipitation western ridges
later Thursday night into Friday.
As of 330 AM EST Monday...
Record warm Mins for March 1
Roanoke.....52 in 1918
Lynchburg...57 in 1910
Danville....51 in 2012
Blacksburg..45 in 1997
Bluefield...56 in 1997
Record highs for March 1
Roanoke.....76 in 1972
Lynchburg...78 in 1918
Danville....80 in 1972
Blacksburg..72 in 1976
Bluefield...78 in 1997