- Day Three
acus01 kwns 161632
Storm Prediction Center ac 161630
Day 1 convective outlook
National Weather Service Storm Prediction Center Norman OK
1130 am CDT sun Jun 16 2019
Valid 161630z - 171200z
..there is an enhanced risk of severe thunderstorms across central
..there is a slight risk of severe thunderstorms from the Ohio
Valley to the Middle-Atlantic States...
Severe thunderstorms are most likely across a large part of central
Texas during the late afternoon and evening, including a few
tornadoes aside from more prevalent large hail and damaging winds.
Other severe storms are expected from the Ohio Valley to the
Although more progressive across east-central Texas, multifaceted
outflow (and other wavelike features) continues to generally
decelerate across north-central Texas south of the metroplex
west-southwestward into the Big Country/Concho Valley, where it
loosely connects to a surface low in vicinity of the Pecos River
across southwest Texas. Some northward recovery may occur as these
features otherwise gradually decay. Regardless, a strongly to
extremely unstable air mass will otherwise develop through the
afternoon near/south of these remnant boundaries with ample moisture
beneath a residual elevated-mixed layer (reference 12z Midland and
del Rio observed soundings) that extends into
Surface-based storms are expected to initially develop and quickly
intensify this afternoon near aforementioned (albeit modified)
outflow, and also along the dryline bulge near the Concho Valley.
Given the degree of instability, a belt of modest mid-level
westerlies (20-30 kt at 500 mb) will be adequate for supercells and
multicell clusters amid the large buoyancy Reservoir.
All severe risks are possible, including damaging winds and
destructive wind-driven large hail, especially ss storms consolidate
into a potentially massive south/southeastward-moving mesoscale convective system this
evening with embedded bows and supercells. A severe threat may
persist tonight southeast towards the Gulf Coast despite increasing
..Ohio River valley to mid-Atlantic states/Delmarva...
Multiple rounds of prior convection/related outflow across the Ohio
Valley has effectively established a west/east corridor of preferred
storm redevelopment/destabilization through the afternoon. A
decaying band of convection and mesoscale convective vortex across the middle Ohio River
valley toward the central Appalachians will influence downstream
development later today into the mid-Atlantic region/Delmarva
vicinity, although the movement of the mesoscale convective vortex may outrun more
appreciable influx of low-level moisture and peak destabilization.
Farther to the west, warm front-resembling modification continues to
occur with prior outflow across the lower Ohio Valley vicinity
(southern portions of Illinois/in and western ky) ahead of an mesoscale convective vortex across
southern Missouri. With near 70f surface dewpoints and ample
early-day insolation (south of early convection), moderate to
locally strong destabilization is expected to quickly occur this
afternoon, supporting an intensification and areal increase in
Overall, across these regions where storms develop/intensify,
modest-strength westerlies will support eastward-moving multicell
clusters/evolving linear segments, with the more intense storms
capable of wind damage, some hail, and a non-zero tornado risk.
..north-Central High plains...
Weak convergence/upslope and differential heating near higher
terrain will contribute to isolated/widely scattered thunderstorm
development this afternoon. While the ambient air mass is not overly
moist (generally 40s to lower 50s f surface dewpoints), adequate
moisture and steep lapse rates will yield minimal inhibition and
modest buoyancy (500-750 j/kg mlcape) by peak heating. Buoyancy and
effective shear should be regionally maximized across the southern
Nebraska Panhandle/southwest Nebraska and far northeast Colorado,
although the potential for isolated strong to severe thunderstorms
capable of hail/wind will exist across a broader part of the region
mainly late this afternoon through mid-evening.
acus11 kwns 161731
sels mesoscale discussion
Storm Prediction Center mesoscale discussion 161731
Mesoscale discussion 1091
National Weather Service Storm Prediction Center Norman OK
1231 PM CDT sun Jun 16 2019
Areas affected...Texas Big Country into north central Texas
Concerning...severe potential...watch likely
Valid 161731z - 161830z
Probability of watch issuance...80 percent
Summary...thunderstorms are in the process of initiating, with rapid
intensification and an increase in coverage probable through 3-4 PM.
This is expected to be accompanied by the risk for severe hail,
perhaps a tornado, and a gradual increase in risk for potentially
damaging wind gusts.
Discussion...thunderstorm activity appears to be in the process of
initiating northwest through northeast of Abilene, toward the
Mineral Wells area. This may be supported by lift associated with
an area of enhanced lower/mid tropospheric warm advection, on the
northern periphery of the plume of warm and capping elevated
mixed-layer air (around 700 mb). This is also just ahead of the
leading edge of mid-level cooling now advancing south/southeast of
the Panhandle into the South Plains.
While activity may be initially rooted above the boundary layer, its
proximity to an area of enhanced low-level convergence near
intersecting outflow boundaries may contribute to a transition to
boundary-layer based storms. Once this occurs, large mixed-layer
cape (already on the order of 3000-4000 j/kg), will allow for rapid
intensification. Deep-layer mean ambient westerly flow may only be
on the order of 15-20 kt, but shear may be marginally sufficient for
supercell structures initially, with perhaps some early potential
for a tornado. Otherwise, thermodynamic profiles likely are
supportive of large to very large hail, with a gradual increase in
potential for damaging downbursts through 20-21z.
..please see www.Spc.NOAA.Gov for graphic product...
Latitude...Lon 33180034 33409947 33519762 32719695 32219816 32180034