Scientific Forecaster Discussion
fxus61 krnk 251953
Area forecast discussion
National Weather Service Blacksburg Virginia
353 PM EDT Tue Jun 25 2019
high pressure will settle across the region through Friday
morning. The next chance for widespread rainfall will be
associated with a cold front that approaches the area during the
day Friday and lingers over the area into the weekend.
Near term /through Wednesday/...
as of 210 PM EDT Tuesday...
The cold front has moved to the coast with high pressure
building over the mountains this evening. This ridge is not
deep, but with wet soils some Mountain Valley fog is possible
during the early morning hours Wednesday. With high pressure at
the surface and zonal flow aloft, Wednesday will be rain-free
with afternoon temperatures ranging from the 80s across the west
and near 90f east of the Blue Ridge.
Short term /Wednesday night through Friday night/...
as of 330 PM EDT Tuesday...
An upper level ridge and surface high pressure will support
northwest windflow across the area, which is expected to cap the
atmosphere during the middle of this week. This will make
getting a shower or thunderstorm to develop on Thursday quite
difficult, with best chances of very isolated activity occuring
along the crest of the Blue Ridge with afternoon heating.
Better coverage of showers/storms is expected on Friday upper
level ridging develops across the central United States, while
surface high pressure pushes east, allowing winds to swing more
southerly. May see showers and storms fire along the crest of
the Blue Ridge with afternoon heating, followed later in the day
possibly by more organized thunderstorm activity moving into
the area from the northwest associated with a strong upper level
disturbance. Will keep an eye on the development of this
scenario in the coming days.
Long term /Saturday through Tuesday/...
as of 345 PM EDT Tuesday...
Expect upper level ridging across the central United States
toward the end of the week, resulting in northwest windflow
aloft across the mid-Atlantic. Given strong heating on Saturday
and Sunday, will have to keep an eye on any disturbances
approaching from the Great Lakes region, which could trigger a
line of strong thunderstorms. Confidence on timing, track and
even development of these storms is low that far into the
future. Chances for thunderstorm activity do increase Sunday
night however as a cold front is expected to approach from the
north, with the front possibly entering and stalling across our
area on Monday.
Aviation /20z Tuesday through Sunday/...
as of 120 PM EDT Tuesday...
Widespread VFR conditions will persist through the taf forecast
period at all sites. Through the afternoon, gusty winds can be
expected at most of the mountain taf sites, including kroa, but
gusts are forecast to be 25kts or less. These winds will subside
Late tonight, IFR cigs and visibilities are expected, especially at
the Mountain Valley taf sites (klwb and kbcb) as light winds and a
moist ground help generate fog and stratus in some places.
The combination of a weak surface ridge and zonal flow aloft will
keep the area rain-free Wednesday. Some scattered to broken clouds
are possible along and south of the Virginia/NC border, but VFR none the
Confidence in the above portion of the forecast is very high.
Extended aviation discussion...
High pressure is expected to take up residency over the region
through Friday. For the most part, VFR conditions are expected
outside of late night/early morning fog. Also, as we approach the
weekend showers and storms will be on the increase, and these too
may bring some temporary reductions to visibility and ceilings.
Late Friday into Saturday, the chances of sub-VFR conditions
increase with the passage of a backdoor cold front and an increase
in coverage of showers and storms.
Confidence in the above aviation forecast discussion is moderate.