U.S. Severe Weather Forecast (Convective Outlook)

Day Three

acus01 kwns 010504 
Storm Prediction Center ac 010502 

Day 1 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
1202 am CDT Wednesday Oct 01 2014 

Valid 011200z - 021200z 

..there is a slight risk of severe thunderstorms across eastern and northern Kansas...Southern and 
eastern Nebraska...western and central MO...far northestern OK... 

Severe thunderstorms capable of very large hail...localized damaging 
winds and a tornado or two are likely across much of eastern Kansas 
into western Missouri and far northeastern Oklahoma during the day. 
Other strong to severe storms with hail and wind will be possible 
across central Nebraska during the late afternoon...as well as from 
eastern Colorado into northern Kansas and southern Nebraska 

A large area of cyclonic flow aloft will extend from The Rockies 
into the plains with a broad area of low pressure from southwestern Kansas into 
northwestern Texas. A leading shortwave trough will affect much of eastern Kansas into 
MO early in the day and will result in ongoing areas of storms which 
will complicate the forecast later on. 

Behind this disturbance...southwesterly flow aloft will strengthen although 
height tendencies will be neutral. Still...cool temperatures aloft 
and the presence of dewpoints well into the 60s east of a dryline will 
result in ample instability for strong to severe storms with 
multiple potential areas extending from Colorado into MO through the 

..ern Kansas into western MO...Northestern OK... 
scattered thunderstorms will be ongoing across eastern Kansas into MO in 
association with the leading shortwave trough and in a zone of 
persistent low-level warm air advection. Some hail is possible with 
this early activity. However...the greatest threat will be during 
the afternoon and early evening when heating near the western fringe of 
the outflow/differential heating zone results in strong instability. 
The strongest shear profiles will also exist in these areas with 
20-25 knots 850 mb flow atop S/southeasterly surface winds near the boundary 
resulting in effective srh potentially on the order of 200-300 
m2/s2. Supercells capable of very large hail are likely...and a 
couple tornadoes may also occur depending on how the low-level 
boundary situation develops during the day. 

Farther east across central MO...early storms that form over eastern Kansas/western 
MO may increase in intensity and evolve into a damaging wind threat. 
Veering low-level winds further suggest that even if the storm Mode 
is linear...embedded areas of rotation may exist. 

..cntrl/eastern Nebraska during the day... 
A weak low-pressure trough will be nearly stationary across central 
Nebraska during the day. Strong heating and steep lapse rate profiles 
will lead to an uncapped atmosphere with isolated storms likely. 
Low-level winds will be weak but deep layer shear will be sufficient 
for a few supercells capable of large hail. 

..ern Colorado late afternoon into Kansas and Nebraska overnight... 
High-based thunderstorms are expected to form along a surging cold 
front across central Colorado by early afternoon...then are expected to 
gradually grow upscale as the front emerges into the plains. Strong 
wind gusts and/or small hail will be likely initially...with a 
severe threat possibly developing during the evening and overnight 
as the strong forcing interacts with stronger instability and 
moisture over Nebraska and Kansas. Damaging winds and hail will be possible 
with only a shallow surface stable layer in place. 

..wrn OK into northwestern Texas... 
A conditional threat of hail will exist during the late afternoon 
near a retreating dryline. Heating will be strong...and a narrow 
zone near the dryline should become uncapped. While convergence is 
weak...isolated storms cannot be ruled out. If they form...they will 
likely be cellular with a hail threat. 

.Jewell/Rogers.. 10/01/2014 

Mesoscale Discussion

acus11 kwns 302222 
sels mesoscale discussion 
Storm Prediction Center mesoscale discussion 302221 

Mesoscale discussion 1781 
National Weather Service Storm Prediction Center Norman OK 
0521 PM CDT Tuesday Sep 30 2014 

Areas affected...parts of central Kansas 

Concerning...severe potential...watch unlikely 

Valid 302221z - 302315z 

Probability of watch issuance...20 percent 

Summary...scattered thunderstorms are developing along and east of a 
weak surface trough/dryline...but poor midlevel lapse rates and 
modest low-level moisture will limit cape and any associated 
hail/wind risk. 

Discussion...surface heating/mixing has removed convective 
inhibition and scattered thunderstorms are forming along the zone of 
diffuse low-level convergence from the NE Texas Panhandle to near the 
intersection with a diffuse outflow boundary near hys. Deep-layer 
vertical shear is at least marginally favorable for 
supercells...with somewhat stronger vertical shear near the outflow 
boundary close to I-70. The storms will slowly strengthen while 
spreading northeastward...but only middle-upper 50s boundary layer dewpoints and 
midlevel lapse rates at or below 6 c/km in the warm sector will limit MLCAPE 
to around 1000 j/kg. Thus...the hail/wind risk will be marginal at 
best in the warm sector...with the strongest storms possible where 
warm sector convection encounters a little Richer moisture and 
stronger low-level shear while interacting with the outflow 
boundary. The overall severe risk appears too marginal to warrant a 
watch at this time. 

.Thompson.. 09/30/2014 

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


Latitude...Lon 39179900 39519768 39739680 39639654 39369652 38689724 
38089790 37619842 37249894 37089947 37309973 38149943 
38849936 39179900