U.S. Severe Weather Forecast (Convective Outlook)

Day Three

acus02 kwns 180656 
Storm Prediction Center ac 180655 

Day 2 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
1255 am CST sun Feb 18 2018 

Valid 191200z - 201200z 

..no severe thunderstorm areas forecast... 

showers -- possibly with occasional/embedded lightning -- will be 
possible over parts of the intermountain west Monday. More numerous 
thunderstorms are expected from the Oklahoma vicinity 
north-northeast toward the upper Great Lakes region. 

Highly amplified upper flow is forecast across the U.S. Monday, with 
a large/long-wave trough encompassing the western 2/3 of the country 
while a Stout Ridge remains in place off the southeastern U.S. 
Coast. As shorter-wavelength troughing -- within the larger-scale 
cyclonic flow field -- shifts slowly east across the intermountain 
west, polar air is forecast to continue spreading south/southeast 
across the north-central and western portions of the country. A 
cold front -- demarcating the leading edge of this cold surge -- 
should extend from the upper Great Lakes region southwest across the 
southern High Plains, with a broad zone of low-level warm advection 
affecting a broad swath of the country from the Southern Plains 
northeast to the Great Lakes. 

Showers -- and possibly some occasional/embedded lightning -- will 
affect portions of the interior west, steep lapse rates/cold 
mid-level air associated with upper troughing spread across the 
area. More numerous/elevated showers and thunderstorms are expected 
-- particularly during the second half of the period -- across 
portions of the central U.S., In conjunction with the aforementioned 
area of low-level warm advection. Although some small hail may 
occur with a few stronger cells, severe weather is not expected. 

.Goss.. 02/18/2018