U.S. Severe Weather Forecast (Convective Outlook)

Day Three

acus01 kwns 230048 
Storm Prediction Center ac 230047 

Day 1 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
0747 PM CDT Friday Aug 22 2014 

Valid 230100z - 231200z 

..there is a slight risk of severe thunderstorms across the Central Plains... 

scattered severe thunderstorms will spread across the Central Plains 
tonight. The primary threats are large hail and damaging winds. 
Isolated tornadoes are also possible. 

..Central Plains... 

Well defined upper vorticity is lifting northeastward across the 4-corners into 
southwestern Colorado. Corridor of stronger flow aloft is now spreading across 
the High Plains and appears to be aiding organization of convection 
over eastern Colorado/western Kansas. Several thunderstorm clusters are evolving 
across this region with one maturing complex over eastern Colorado and a 
notable mesoscale convective vortex over Lincoln County. Another possible mesoscale convective vortex is forming 
along the western end of a complex over southern Decatur County Kansas. Both of 
these complexes are lifting north-northeastward at roughly 35kt and will soon 
spread into southern Nebraska. Lone supercell has also developed along the 
Kansas/Nebraska border within favorably moist/sheared low level airmass. 
Isolated tornadoes remain possible with supercell 
structures...especially north of the boundary for the next few 
hours...as deep layer shear begins to increase. Later tonight low level jet 
will increase across Kansas/Nebraska and warm advection should drive multiple 
thunderstorm clusters across Nebraska into South Dakota. Large hail/damaging 
remain the primary threats. 


Isolated strong storms may linger across eastern Idaho for the next few 
hours...aided in large part by strong upper trough and lingering 
instability. Other isolated storms are possible across a broad 
swath of the middle MS valley/Ohio Valley within weak warm advection 
regime. Large scale forcing will remain negligible across the middle 
MS/Ohio Valley region and do not anticipate sufficient 
coverage/intensity to warrant more than 5 percent severe probs. 

.Darrow.. 08/23/2014 

Mesoscale Discussion

acus11 kwns 230048 
sels mesoscale discussion 
Storm Prediction Center mesoscale discussion 230048 

Mesoscale discussion 1601 
National Weather Service Storm Prediction Center Norman OK 
0748 PM CDT Friday Aug 22 2014 

Areas affected...northestern Colorado...northwestern and north central Kansas...southwestern Nebraska 

Concerning...Severe Thunderstorm Watch 473... 

Valid 230048z - 230245z 

The severe weather threat for Severe Thunderstorm Watch 473 

Summary...damaging winds and hail will remain possible through this 
evening as storms move out of Kansas and Colorado into Nebraska. 

Discussion...severe storms from eastern Colorado into northwestern Kansas continue to 
evolve northward aided by a meridional shortwave-trough. Storms have 
organized into two main lines which should continue to propagate 
north-northeastward into Nebraska later this evening. Other isolated storms were 
ongoing across southwestern Nebraska near the front where hodograph length is 
maximized with northeasterly surface winds. The 00z lbf sounding further 
supports supercells and a hail threat. 

A strengthening low-level jet and continued northward advancement of the 
shortwave trough should help storms remain strong well into the 
evening with mainly a wind and hail threat. 

.Jewell.. 08/23/2014 

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


Latitude...Lon 38990326 39000349 39870373 40480335 40950270 41460158 
42259952 42279857 41929799 41039752 40329755 39929803 
39219871 39019951 39000015 39310053 39270130 39170198