- Day Three
acus01 kwns 182001
Storm Prediction Center ac 182000
Day 1 convective outlook
National Weather Service Storm Prediction Center Norman OK
0300 PM CDT Tue Jun 18 2019
Valid 182000z - 191200z
..there is an enhanced risk of severe thunderstorms from West Texas
..there is a slight risk of severe thunderstorms across portions of
the plains and middle Atlantic...
Scattered severe thunderstorms are likely across parts of the
central and southern Great Plains in multiple rounds this afternoon
through tonight. Other severe thunderstorms are expected across the
mid-Atlantic region and parts of the southeast.
Remnants of long-lived mesoscale convective system are progressing along the I-70 corridor
across Kansas. Leading edge of this activity is beginning to intensify
over northeast Kansas which may propagate a bit farther downstream than
earlier anticipated. Will expand higher severe probs across portions
of top County Warning Area to account for these trends.
Strong boundary-layer heating across the High Plains has contributed
to near-dry adiabatic low-level lapse rates from southeast Colorado into
West Texas. Convection will gradually expand in areal coverage along
this corridor over the next few hours before spreading into the enh
Previous discussion... /issued 1152 am CDT Tue Jun 18 2019/
An mesoscale convective vortex will continue to drift generally eastward across
western/central Kansas through the afternoon and evening. A trend of
thinning/increasingly scattered cloud cover should occur through the
afternoon, aided by a modest mesoscale convective vortex-peripheral dry slot. Expectations
are for more of a southeasterly low-level wind component to
materialize across central Kansas by mid/late afternoon, while
enhanced mid-level winds otherwise spread eastward across the
southern half of Kansas. Thunderstorms should initially intensify
across central/south-central Kansas by mid-afternoon, with moderate
buoyancy and sufficient deep-layer shear/modest overall forcing
likely being conducive for semi-discrete supercells, at least for a
few hours duration. A few tornadoes will be possible aside from
severe hail/wind as storms spread east-southeastward toward and
across the I-35/I-135 corridor through late afternoon and
..Oklahoma/Texas Panhandle to west/southwest Texas...
Timing of the peak/most-certain severe risk is a bit questionable
across parts of this region, but the potential exists for a
sub-regional corridor to be impacted by multiple rounds of severe
thunderstorms. At the very least, a conditional severe/supercell
risk will exist as early as mid/late afternoon across the Texas
Panhandle/Low Rolling Plains and western Oklahoma within a very
unstable environment. However, modest convergence and a tendency for
mid-level warming casts some uncertainty. At the very least, storms
are likely to move into/across the region later this evening with an
appreciable damaging wind/hail risk via one or more well-organized
Farther south, a couple supercells should form over the higher
terrain of the Texas trans-Pecos with a primary risk of large hail.
Minor mid-level height rises suggest robust mlcin will hold east of
the Pecos River, limiting the spatial extent of this threat. A
separate area of thunderstorms may form near the intersection of the
dryline and residual outflow boundary trailing from the central
Texas mesoscale convective system. A deeply mixed boundary layer should support a few
supercells that might organize into a cluster this evening. Large
hail and severe wind should be the primary threats.
..co Front Range/south-Central High plains...
Scattered thunderstorm development is likely over the Raton Mesa and
other parts of southeast Colorado by peak heating as a minor
mid-level impulse in Utah crosses the southern rockies. Amid 30-40
kt 500-mb westerlies, this activity should spread east and impinge
on Richer boundary-layer moisture in the Texas Panhandle this
evening. At least on an isolated basis, supercells capable of large
hail and possibly some tornado/damaging wind risk can be expected as
storms spread east/southeastward.
An area of organized severe potential is apparent across southeast
PA, NJ, northern MD, and Delaware ahead of an mesoscale convective vortex/weak surface cyclone
currently over western PA. Here, some enlargement to low-level
hodographs in conjunction with moderate boundary-layer heating of
low 70s dew points should support a risk for a few supercells
capable of a tornado or two and damaging winds/some hail. Refer to
mesoscale discussion 1115 for additional short-term details.
..central Gulf Coast to Carolinas...
A belt of 20-30 kt west-southwesterly flow will persist amid
afternoon MLCAPE of 1000-2000 j/kg. This should again Foster a
threat for mainly locally damaging wind as numerous multicells occur
through this afternoon.
..Montana/northern High Plains...
Isolated strong to severe semi-low-topped thunderstorms will be
possible this afternoon into evening within a modestly
moist/unstable environment ahead of an
amplifying/southeastward-moving mid-level shortwave trough.
Well-mixed boundary layers could yield severe-caliber wind gusts
along with some localized/marginal hail potential.
acus11 kwns 182149
sels mesoscale discussion
Storm Prediction Center mesoscale discussion 182148
Mesoscale discussion 1124
National Weather Service Storm Prediction Center Norman OK
0448 PM CDT Tue Jun 18 2019
Areas affected...Texas Panhandle and Texas Caprock vicinity
Concerning...severe potential...Severe Thunderstorm Watch likely
Valid 182148z - 182245z
Probability of watch issuance...80 percent
Summary...storms are expected to move east into an area of Richer
low-level moisture over the Texas South Plains and intensify. Large
hail and severe gusts are the primary risks.
Discussion...radar mosaic shows isolated, high-based thunderstorms
over the eastern plains of nm. Surface observations show
temperatures in the lower 90s degrees f over eastern nm with surface
dewpoints mixing into the 40s. Farther east, dewpoints range from
the lower 50s near the nm/Texas border into the lower 60s near the I-27
corridor. As a result, MLCAPE increases from west to east across
Westerly flow aloft strengthens from 30kt around 400mb to 75kt at
200mb. The presence of steep low- to mid-level lapse rates (in
excess of 8 degrees c/km) underlying high-level shear in the -10 to
-30 degrees c layer, suggest large to very large hail is possible
with the strongest updrafts. Upscale growth into storm clusters and
perhaps a linear band will serve as a transition for severe gusts to
become the primary risk late this evening.
..please see www.Spc.NOAA.Gov for graphic product...
Latitude...Lon 35560183 35540054 35220007 34149996 33180028 32980100
33040213 33490269 34600286 35270254 35560183