U.S. Severe Weather Forecast (Convective Outlook)

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. 

.Guyer/Broyles.. 05/26/2019 


Mesoscale Discussion

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 
western Ohio. 

.Broyles/guyer.. 05/26/2019 

..please see www.Spc.NOAA.Gov for graphic product... 


Latitude...Lon 39558427 39538628 39678671 40118689 40808681 40998634 
40938414 40168404 39868407 39558427