Area Forecast Discussion
Issued by NWS Blacksburg, VA

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FXUS61 KRNK 160636

Area Forecast Discussion
National Weather Service Blacksburg VA
236 AM EDT Sun May 16 2021

A warm front will help to bring scattered showers ad perhaps a
few thunderstorms to the area through Tuesday. High pressure
strengthens over the Mid-Atlantic by mid week and persists
through next weekend, bringing a period of dry and warm weather.


As of 215 AM EDT Sunday...

The CONUS will remain in a split flow regime in the near term,
with an active northern stream over Canada, the northern Great
Lakes, and the northeast, and a southern stream covering the
southern third of the country. WSW flow over Appalachia will
steer weak short wave energy over the area, providing some
chances for showers today and perhaps a few claps of thunder
this afternoon.

A wavy frontal boundary extended from low pressure near the OK
and TX panhandles towards KY/WV/VA. The (warm) front will lift
north today and provide somewhat of a focus for any convection
that can develop. Radar imagery is showing some echoes
developing to our west and southwest already. However, last
night`s KRNK sounding shows we do have some drier air to
overcome before we get any rain this morning, and that will be a
limiting factor in storm total QPF as isentropic lift ramps up
today. Instability will be on the low end due to the extent of
cloud cover...but right along the front there may be enough
convergence for some weak thunderstorms, mainly this afternoon.

Cloud cover will keep temperatures a few degrees cooler than
yesterday despite increasing WAA in light westerly winds. The
warm front remains in the area overnight into early Monday, but
shower coverage will be markedly reduced with the loss of
daytime heating. We`ll remain overcast with lows generally
warmer than tonight and in the upper 40s to lower 50s.

/Confidence Levels in Forecast Parameters/
- High Confidence in Temperatures,
- Moderate Confidence in Precipitation Probabilities,
- High Confidence in Wind Directions and Speeds


As of 230 AM EDT Sunday...

...Unsettled Weather Expected Monday and Tuesday Before Dry High
Pressure Settles In Mid Week...

Low pressure in the west central U.S. strengthens, lifting a warm
front into the Mid-Atlantic Sunday into Monday. This front, combined
with NW flow aloft and mid level disturbances will provide
additional shower and thunder storm chances for both Monday and
Tuesday. The difference between the two days will be available
instability. While the energy is there Monday to fire showers and
maybe an isolated thunder storm or two, overall instability will be
lacking due to ample cloud cover: Tuesday, however, will feature
better instability thanks to clearer skies. That instability should
help drive more thunderstorm activity, with best chances remain west
of the Blue Ridge.

Temperatures wise, ample cloud cover Monday is going to keep
temperatures down, with areas in the east struggling to even reach
70 degrees for the day. Meanwhile areas in the west will sit in the
mid 50s to mid 60s.

After Tuesday, an upper level ridge and its surface high starts to
settle into the Mid-Atlantic: this brings a big change in our
overall weather pattern, ushering in a more summer time like pattern
as temperatures start to swell. Precipitation chances have decreased
Wednesday and into the end of the work week as subsidence looks to
be strong enough to mostly overpower any diurnally driven

Little precipitation over this period may start to become a concern
for starting drought conditions as we are already running behind for
this year.

Forecast confidence is moderate.


As of 230 AM EDT Sunday...

...Dry High Pressure Persist Until Late Weekend...

High pressure remains settled over the Mid-Atlantic through the end
of the work week before it starts to shift southward. Guidance is in
decent agreement that the subtropical high will start to shift
southward going into the start of the weekend. This in turn opens
the area up to a possible backdoor front that could push some rain
chances down into the area, which would not be a bad thing at that
point with several warm days expected with no rainfall. That
mentioned, temperatures going into the long terms look toasty with
areas in the east expected to reach 90s by Saturday as 850
temperatures look to swell to +16 degrees.


As of 225 AM EDT Sunday...

VFR conditions should continue through the period. A warm front
will approach from the west this morning, keeping overcast VFR
skies around for the remainder of the TAF cycle. Ceilings will
hover in the FL050-FL035 range throughout the day. Scattered
showers will shift eastward during the day, so kept VCSH in for
most TAF sites. LYH may not see any showers until the afternoon,
and DAN has the lowest chance of seeing any shower activity. By
the afternoon, ceilings may approach MVFR along and west of the
Blue Ridge with BLF having the highest chance of reaching this
threshold. There will be little if any -TSRA, but a strike or
two is possible. LLWS should not be an issue with winds
increasing to light and westerly after 12Z.

Extended Aviation Discussion...

Ceilings and visibilities could fall toward MVFR and maybe even
lower Monday morning due to low clouds and fog. Prevalent cloud
cover and scattered showers will persist for Monday through
Wednesday as a warm front continues to linger in the area. Even
a few thunderstorms are possible, but confidence is too low to
pinpoint where and when yet. By Thursday, high pressure will
bring warmer and drier weather along with VFR conditions.





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