FXUS61 KRNK 161145

Area Forecast Discussion
National Weather Service Blacksburg VA
745 AM EDT Sun Jun 16 2019

A wavy front will drift across the Ohio Valley and Mid Atlantic
region today through Monday. Low pressure tracks east along the
front Thursday and Friday. The region will remain in the warm
and humid air on the south side of this boundary through the end
of the week with a daily threat of showers and thunderstorms.


As of 400 AM EDT Sunday...

Band of showers and thunderstorms was crossing southern Ohio
around 4AM in association with a short wave that will track
into northeast Pennsylvania by this evening. The best chance of
precipitation will be north of I-64 this morning then along the
southern Blue Ridge this afternoon where there is some low level
convergence in the surface and low level wind.

The overall mean flow is out of the west through mid levels of
the atmosphere which will limit shower and thunderstorm
development east of the Blue Ridge. Areal coverage will be
isolated to widespread. In general leaned toward HiRes-arw for
location of precipitation today and tonight. 0-6km bulk shear
will be marginal and with the limited coverage of thunderstorms
the threat of any severe storms is not zero but only marginal as

Precipitable water values have climbed to around 1.0 inch as of
the 00Z Sunday sounding and will continue to increase into the
1.25 to 1.75 inch range by the end of the day. Surface dew
points will be well into the 60s today which will aide in
pushing CAPES into the 1000-1500 J/kg range today. The moisture
will also limit drop in temperatures overnight. Stayed closer to
warmer guidance for lows.


As of 300 AM EDT Sunday...

The early half of the workweek will be marked by scattered
convection as a series of disturbances pass along a slow moving cold
front north of the Ohio River. As such, showers and thunderstorms
will be most commonly found from far western Virginia and southeast
West Virginia through the Interstate 64 corridor, where greatest
instability associated with these disturbances will be found.
Elsewhere, convection will be driven mainly by daytime heating,
where showers and storms develops along the mountain ridges during
early afternoon, and drift eastward across the Piedmont during late
afternoon/evening in hit & miss fashion. Lowest coverage of rainfall
will be found across the Piedmont region of north-central North
Carolina, most influenced by ridging across the southeast states.

Looking to Monday, will be keeping an eye on a somewhat strong wave
of low pressure that will pass east across northern West Virginia
and Maryland, which looks sufficiently strong to draw a broken line
of storms across the Virginia Piedmont during the evening. Given
CAPEs in the 1200-1800 J/Kg range and bulk shear in the 25-30 knot
range, we can expect a few storms to be strong and possibly severe,
with damaging winds the primary threat. May also see some locally
heavy downpours given PWATs in the 1.4 to 1.6 inch range, however
storms should remain progressive, not lingering over any location
for extended periods of time.

A similar story exists for Tuesday, though with greater coverage of
rainfall expected given the passage of Monday's wave will nudge the
front closer to our region, likely with outflows from the previous
night's storms lingering across the area. In addition to a few
strong storms packing gusty winds, the Weather Prediction Center has
southeast West Virginia and the Interstate 64 corridor of Virginia
outlined in a marginal risk for excessive rainfall for the slightly
increased potential for training storms.

Wednesday is looking to be the least active day of the period as a
strong wave of low pressure sets up across the Midwest, causing the
front to lift northward, away from our area, as a warm front. Still
quite moist however, so spotty daytime heating-driven showers and
storms will be in play, more so for the mountains.

Temperatures each day across our area will be near normal for mid-


As of 330 AM EDT Sunday...

Expect an active pattern for Thursday as a wave of low pressure
moves across the Ohio Valley during the day, pushing into the mid-
Atlantic Thursday night. Friday appears drier with a west-northwest
flow under a flat ridge, but still cannot rule out a few
showers/storms in the higher elevations in the afternoon. Some
difference lies between the operational GFS/ECM for Saturday with
the ECM showing a strong ridge at 5h across the southeast with a
shortwave moving across the midwest, while the GFS is flatter and
faster with the next system. Ensembles are more of a blend of the
two, and keep the main activity across the Ohio Valley/Midwest, but
allow for a chance of showers/storms Sat afternoon.

Temps/humidity remain elevated, but Friday into Friday night could
see a brief reprieve in the humidity, but not quite as cool as what
we just had.


As of 740 AM EDT Sunday...

VFR conditions are expected across southwest Virginia,
northwest North Carolina and southeast West Virginia through

A short wave over northern West Virginia will track into
northeast Pennsylvania today. The tail of this wave may bring
showers and isolated thunderstorms, along with the associated
MVFR ceilings and visibilities, mainly north of I-64. The most
likely TAF location to have precipitation before 21Z/5PM will
be KLWB so have included VCSH in the forecast. Have included
VCSH at KBCB, KROA and KBLF after 21Z. Areal coverage of showers
and thunderstorms will be isolated and the chance of
precipitation at at specific airport is low. Mid and high
clouds from upstream showers and thunderstorms will cover much
of the area this evening but ceilings will be VFR.

Confidence in ceilings and visibility is above average.
Confidence on timing and location of thunderstorms is average.

Extended Aviation Discussion...

By Monday into the most of the remainder of the week the chance
of afternoon showers and thunderstorms increases as a
stationary front hangs just to the north of the region. Periods
of MVFR will be likely in storms, and depending on degree of
overnight clearing some periods of early morning IFR fog are
possible in any locations that get afternoon/evening rainfall.




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