- Day Three
acus01 kwns 261257
Storm Prediction Center ac 261256
Day 1 convective outlook
National Weather Service Storm Prediction Center Norman OK
0756 am CDT sun may 26 2019
Valid 261300z - 271200z
..there is a moderate risk of severe thunderstorms across eastern
Colorado...western Kansas...and the Oklahoma and Texas panhandles...
..there is a slight risk of severe thunderstorms from the Ohio
Valley to the Middle-Atlantic States...
Severe thunderstorms are likely today into tonight across much of
the Central Plains and southern High Plains, with all aspects of
severe weather expected. Additional severe thunderstorms are
possible across the lower Ohio Valley to the mid-Atlantic coast,
accompanied by a risk for severe wind and hail.
..Central Plains/southern High Plains...
A moderate risk has been introduced for the region with an eastward
expansion of the enhanced risk. Large hail and several tornadoes,
possibly a couple strong, are expected particularly from mid/late
afternoon through early/mid evening, with the damaging wind risk
also increasing this evening as storms progress east-northeastward.
A readily evident shortwave trough/speed Max per water vapor imagery
centered over northern baja Mexico early this morning will quickly
eject northeastward with this lead shortwave trough taking on an
increasingly negative tilt as it reaches the south-Central High
plains by early evening. This will be in tandem with increasingly
strong southwesterly mid-level winds (45-60 kt in the 700-500 mb
layer). After multiple days of semi-extensive convection and
multiple sub-regional areas of more notable overturning,
strengthening southwesterly trajectories via southwest U.S./Northern
Mexico will lead to a reestablishment and broadening of
northeastward-advancing elevated mixed layer across the
central/southern High Plains today.
Moisture return to the deepening surface trough across the Central
High plains is already underway beneath north/northeastward
advecting warm elevated mixed-layer air. Models indicate that this
will contribute to moderate to large cape across much of the High
Plains, and into the warm sector of the developing cyclone across
the Central Plains.
There will likely be a corridor of moderate to strong boundary layer
destabilization across the Texas/Oklahoma panhandles into eastern
Colorado by mid to late afternoon, which will be sufficient to
support propagation of thunderstorm activity off The Rockies into
the High Plains. In the presence of strengthening shear, the
environment is expected to become conducive to intense supercells
with potential for large to very large hail. Although low-level
hodographs may initially be modest in length and curvature, a few
tornadoes appear likely, particularly from the Colorado/Kansas
border area eastward along an effective front across western Kansas,
as well as southward into the Panhandle region.
Low-to-mid-tropospheric winds, particularly within the lowest 3-4 km
agl, are likely to notably increase this evening. Various global
guidance suggests a steady strengthening of 700 mb winds (50+ kt)
from the Texas Panhandle/northwest Oklahoma across much of Kansas.
Pending convective Mode, this could increase the tornado threat
early this evening, while also contributing to upscale growth into
one or more forward-propagating clusters with a heightened damaging
wind risk, most probable across Kansas/southern Nebraska, but
perhaps also the eastern Texas Panhandle into western Oklahoma.
..northern High Plains...
Isolated/widely scattered severe thunderstorms capable of large hail
and locally strong winds are expected across the region particularly
late this afternoon through evening, with upwards of 30-40 kt
effective shear and moderate buoyancy supportive of a combination of
supercells and multicells.
..lower Ohio Valley to the mid-Atlantic coast...
An eastward-moving mesoscale convective system/mesoscale convective vortex will continue to cross the upper Ohio
Valley this morning. This feature may help to focus intensifying
development downstream by afternoon. Otherwise, models indicate that
seasonably high boundary layer moisture content ahead of the
southward advancing front will become characterized by moderate cape
by this afternoon. This will support potential for organizing
clusters of thunderstorm activity, aided by forcing and shear
associated with the perturbations progressing around the northern
periphery of the subtropical ridge. Flow including 30-40+ kt in the
700-500 mb layer may be sufficient to support occasional isolated
supercells, but severe hail and wind appear the primary hazards in
the presence of generally weak low-level hodographs.
acus11 kwns 260807
sels mesoscale discussion
Storm Prediction Center mesoscale discussion 260806
Mesoscale discussion 0807
National Weather Service Storm Prediction Center Norman OK
0306 am CDT sun may 26 2019
Areas affected...central and eastern Indiana...western Ohio
Concerning...Severe Thunderstorm Watch 248...
Valid 260806z - 260930z
The severe weather threat for Severe Thunderstorm Watch 248
Summary...an isolated wind damage threat is expected to continue
through daybreak across eastern Indiana into western Ohio. Weather
watch issuance will likely be needed to the east of ww 248.
Discussion...the latest radar imagery shows an mesoscale convective system located across
central and northern Indiana. The mesoscale convective system has a bowing segment across
the eastern part of ww 248 where wind damage is likely occurring.
MLCAPE values across central Indiana are estimated to be around 1000
j/kg. In addition, regional WSR-88D vwps have 0-6 km shear in the 30
to 40 kt range with unidirectional westerly flow in the low to
mid-levels. This will likely support a continued wind damage threat
for several more hours as the line moves eastward toward and into
..please see www.Spc.NOAA.Gov for graphic product...
Latitude...Lon 39558427 39538628 39678671 40118689 40808681 40998634
40938414 40168404 39868407 39558427