SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1210 AM CDT Sun Apr 21 2019
Valid 211200Z - 221200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS MAINLY FROM
NORTHERN KANSAS INTO CENTRAL AND EASTERN NEBRASKA...
Marginally severe hail or wind is possible across parts of the
central Plains this afternoon and evening, mainly from northern
Kansas into Nebraska.
An upper low will fill as it remains nearly stationary across the
Mid Atlantic, with high pressure providing stable conditions
generally east of the Mississippi river. Over the Plains, southerly
surface winds will increase as an upper trough amplifies over the
Southwest and low pressure remains over the central Plains. A narrow
plume of mid to upper 50s dewpoints will develop from TX into
southeast NE, resulting in marginal destabilization mainly over KS
Meanwhile, a cold front will develop southward into eastern CO and
western NE during the day, and into the OK and TX Panhandles by
Monday morning. In addition, a weak midlevel disturbance will aid
cooling aloft over CO. The combination of strong heating, sufficient
instability and lift with the front and shortwave trough will result
in scattered afternoon storms, a few of which may produce marginally
severe hail or wind.
Strong heating will lead to a steep lapse rate environment across
the Four Corners states, as well as the central and southern High
Plains. By mid afternoon, showers and weak thunderstorms are likely
to form along the Front Range and into northeastern CO along the
cold front. Wind profiles will be weak, but significant outflow is
likely which will move into northwest KS. Locally gusty winds,
perhaps a severe wind gust, will be possible.
To the east, better low-level moisture will exist, supporting
potentially strong storms capable of hail as well as wind. Some of
this activity will form near the front, but may also evolve out of
leading outflow surging east out of CO. Shear profiles will not be
particularly favorable for any sustained severe threat, but a few
reports of hail and wind are anticipated.