U.S. Severe Weather Forecast (Convective Outlook)

Day Three

acus01 kwns 290508 
Storm Prediction Center ac 290507 

Day 1 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
1107 PM CST Sat Nov 28 2015 

Valid 291200z - 301200z 

..no thunderstorm areas forecast... 

thunderstorms are unlikely across the United States on Sunday. 

..srn plains through the lower MS and Tennessee Valley... 

Broad southwesterly flow aloft will persist over the central U.S. Downstream 
from an upper low centered over the Great Basin and intermountain 
west. Widespread elevated but shallow convective rain showers will 
persist from Texas through the lower MS and Tennessee valleys within zone of 
isentropic ascent along warm conveyor belt. Though a few lightning 
strikes cannot be ruled out with this activity...instability is 
expected to remain too weak for a 10% or greater coverage of 

..cntrl plains... 

A strong upper jet will move through base of the western U.S. Upper low 
circulation and into the Central Plains Sunday night. Ascent and 
steepening middle-level lapse rates within exit region of this feature 
will promote the development of elevated showers overnight over 
portions of Kansas...Nebraska into the middle MS valley. While a few lightning 
strikes cannot be ruled out...the marginal thermodynamic environment 
should limit overall thunderstorm threat. 

.Dial.. 11/29/2015 


Mesoscale Discussion

acus11 kwns 280214 
sels mesoscale discussion 
Storm Prediction Center mesoscale discussion 280214 

Mesoscale discussion 1999 
National Weather Service Storm Prediction Center Norman OK 
0814 PM CST Friday Nov 27 2015 

Areas affected...northwestern Texas...southwestern through north central OK and southeastern Kansas 

Concerning...freezing rain 

Valid 280214z - 280715z 

Summary...freezing rain with rates locally exceeding .05 inch per 
hour now over northwestern Texas into southwestern and central OK will expand northeastward 
through north central OK and southeastern Kansas this evening into the early morning. 

Discussion...this evening a quasi-stationary SW-NE oriented 
baroclinic zone evident at 850 mb remains situated from southwestern Texas 
through central OK into eastern Kansas. Recent radar trends indicate a 
northeastward-expanding area of precipitation from western Texas through southwestern OK. 
This expansion in precipitation appears to be in association with an 
increase in isentropic ascent within the exit region of a 
progressive upper jet moving into the southern High Plains. The Lubbock 
vwp indicate backing of winds in the 4-6 km layer just ahead of this 
feature during the past hour. Moderate southerly winds above the shallow 
stable layer will maintain a significant warm nose with temperatures 
between 5-10c indicated at 850 mb. This should maintain freezing 
rain as the dominant precipitation type from northwestern Texas through 
central/northern OK into eastern Kansas...and the freezing line may creep a little 
farther south overnight given persistent northerly winds with cold 
advection in the surface layer. Convective enhancement to precipitation 
rates is also occurring...mainly from western Texas into western OK where 
steeper middle-level lapse rates exist...and this is where greater ice 
accumulations are likely...especially given surface temperatures in the 
upper 20s. 

.Dial.. 11/28/2015 

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


Latitude...Lon 34700101 36959834 38359608 37789491 35419704 32860125 
33430222 34700101