U.S. Severe Weather Forecast (Convective Outlook)

Day Three

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Storm Prediction Center ac 180815 

Day 3 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
0215 am CST sun Feb 18 2018 

Valid 201200z - 211200z 

..no severe thunderstorm areas forecast... 

thunderstorms are forecast to occur from the Southern Plains 
northeast to the Great Lakes. Showers -- and possibly a couple of 
lightning strikes -- may also occur over The Four Corners vicinity. 

A highly amplified flow field aloft will remain over the U.S. This 
period. Long-wave troughing will remain established over the 
western half to two-thirds of the country, as one embedded 
short-wave trough ejects northeast across the plains but a second 
digs southward across the northwestern states toward the Great Basin 
-- thus resulting in quasi-stationary persistence of the long-wave 

At the surface, cold polar air will continue spreading east and 
southeast across western and central portions of the country. A 
cold front at the leading edge of the cold surge will move east 
across the Great Lakes/Midwest, and southeast across the Ozarks and 
Southern Plains through the period. 

While showers -- and possibly a few lightning strikes -- are 
expected over The Four Corners area, greater thunderstorm coverage 
will remain associated with the advancing cold front, within a zone 
from the Southern Plains to the Great Lakes. 

Showers and elevated thunderstorms are expected across much of 
central and eastern Texas during the period. Some convection may be 
ongoing early in the period, with more widespread precipitation 
spreading southeast with time as the front advances. At this time, 
it appears that thunderstorms associated with the advance of the 
front across Texas during the second half of the period will be 
largely -- if not almost entirely -- confined to the cool side of 
the front. Confluent flow aloft, and a lack of mid-level height 
falls, suggest that large-scale ascent should remain modest at best 
through the deeper troposphere atop the warm sector. As such, 
generally weak convection in an anafrontal-type regime is currently 
expected, which should hinder appreciable severe risk. 

.Goss.. 02/18/2018