- 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.