U.S. Severe Weather Forecast (Convective Outlook)

Day Three

acus01 kwns 240605 
Storm Prediction Center ac 240603 

Day 1 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
0103 am CDT sun Jun 24 2018 

Valid 241200z - 251200z 

..there is an enhanced risk of severe thunderstorms over a portion 
of the central and Southern Plains... 

..there is a slight risk of severe thunderstorms over a portion of 
the central and Southern Plains and the lower Mississippi Valley and 
Tennessee Valley areas... 

Severe storms capable of a significant damaging wind, large hail and 
possibly a few tornadoes are expected from southeast Colorado 
through southwest Kansas, the Texas and Oklahoma panhandles and 
northwest Oklahoma. A few severe storms are also possible from 
northeast Kansas into eastern Nebraska, and from southeast Missouri 
toward Tennessee and Kentucky. 


Shortwave trough currently centered over southwest Montana will advance 
southeast today, reaching the Central High plains this afternoon. A 
cold front from South Dakota through northeast Colorado is advancing south and will 
reach south Colorado later this afternoon. Preceding the cold front an 
outflow boundary associated with ongoing storms is expected to lay 
out across OK and extend west into the Texas Panhandle at the start of 
this period. This boundary may retreat slowly northward as far as 
southwest Kansas during the afternoon. 

..central and southern High Plains region... 

Indications are that the mesoscale convective system currently over northwest OK will still 
be in progress with some threat for damaging wind at the start of 
this period, and this activity will continue east. The storms will 
lay out an expansive outflow boundary that will extend west into the 
Texas Panhandle, and this boundary may retreat slowly northward during 
the day. The atmosphere south of the outflow boundary is expected to 
become strongly unstable with 3000+ j/kg MLCAPE, but with a capping 
inversion resulting from warm air at the base of an elevated mixed 
layer which may limit additional development much of the day. 
However, increasing northeasterly upslope flow over the higher 
terrain of southeast Colorado accompanying the trailing portion of the 
cold front may contribute to thunderstorm initiation later in the 
afternoon. Additional storms may develop along the dryline/outflow 
boundary intersection over the Texas Panhandle. A mid-level jet 
accompanying the mid-latitude shortwave trough will spread through 
the central/southern High Plains above easterly low-level winds 
resulting in sufficient effective bulk shear for some supercells. 
Large hail, and possibly a couple of tornadoes will be the initial 
threats. But storms may eventually grow upscale into an mesoscale convective system and 
continue east in vicinity of the outflow boundary with damaging wind 
becoming the primary threat into the evening across southern Kansas into 
northern and central OK. 

..northeast Kansas through east Nebraska... 

Storms are expected to develop along the cold front where the 
atmosphere will become moderately unstable during the afternoon. 
Wind profiles will undergo some increase with the approach of the 
upper trough with 30-35 kt effective bulk shear supportive of 
multicells and possibly some supercell structures capable of 
damaging wind and large hail through mid evening. 

..northern Arkansas, southern Missouri through west Tennessee and 

Storms will be ongoing over eastern OK and possibly as far east as 
western Arkansas at the start of this period. The downstream atmosphere 
will become moderately unstable, and the remnant progressive mesoscale convective vortex may 
promote the development of additional storms as it advances east. 
Storms may organize into line segments and pose a threat for mainly 
damaging wind through the afternoon. 

.Dial/Wendt.. 06/24/2018 


Mesoscale Discussion

acus11 kwns 240733 
sels mesoscale discussion 
Storm Prediction Center mesoscale discussion 240733 

Mesoscale discussion 0853 
National Weather Service Storm Prediction Center Norman OK 
0233 am CDT sun Jun 24 2018 

Areas affected...east-central Arkansas...southwest Tennessee...and 
northern Mississippi 

Concerning...severe potential...watch unlikely 

Valid 240733z - 240900z 

Probability of watch issuance...20 percent 

Summary...isolated severe thunderstorms capable of large hail will 
be possible through the morning. The limited spatial coverage of 
thunderstorms should preclude the need for a watch. 

Discussion...thunderstorms are developing within a zone of 
850-millibar Theta-E advection. The overall environment in which the 
storms are developing is characterized by most-unstable cape around 
2000 j/kg and is on the southern fringes of a belt of deep-layer 
shear around 30-40 knots. Although the overall environment will be 
supportive of isolated supercell-like structures capable of large 
hail, weak forcing and the overall limited coverage should preclude 
the need for a watch. 

.Marsh/guyer.. 06/24/2018 

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


Latitude...Lon 34659245 35129253 35759185 35829009 35748911 35468851 
34618859 34358964 34429110 34659245