Day 2

Categorical Day 1 Outlook

Probability of a tornado within 25 miles of a point.
Hatched Area: 10% or greater probability of EF2 - EF5 tornadoes within 25 miles of a point.

Probability of one inch diameter hail or larger within 25 miles of a point.
Hatched Area: 10% or greater probability of two inch diameter hail or larger within 25 miles of a point.

Probability of damaging thunderstorm winds or wind gusts of 50 knots or higher within 25 miles of a point.
Hatched Area: 10% or greater probability of wind gusts 65 knots or greater within 25 miles of a point.

000
ACUS01 KWNS 220443
SWODY1
SPC AC 220441

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
1141 PM CDT Sun Apr 21 2019

Valid 221200Z - 231200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM SOUTHEAST NM
ACROSS NORTHWEST TX AND INTO FAR SOUTHWEST OK...

...SUMMARY...
Scattered severe thunderstorms capable of mainly hail and damaging
winds are possible from southeast New Mexico across the South Plains
and into parts of northwest Texas and southwest Oklahoma from late
afternoon Monday through evening. Isolated strong to severe storms
are also possible across parts of southern Wisconsin, eastern Iowa,
and northern Illinois. A weak, brief tornado cannot be ruled out in
either area.

...Synopsis...
An upper low will drop south from AZ into northwest Mexico with a
leading shortwave disturbance moving out of northern Mexico across
west TX. At the surface, a stalling front will stretch roughly from
southeast NM into central OK by 00Z, with winds veering to easterly
across the High Plains. Mid to upper level southwesterly winds will
increase to an average of 40-70 kt respectively, enhancing the
potential for scattered severe storms. 

To the north, a shortwave trough will move into the upper MS Valley
during the afternoon, with a surface low moving from IA into MI.
Southerly winds will increase ahead of this low, enhancing low-level
shear, with the low track becoming a favorable corridor for isolated
severe storms.

...Southeast NM...South Plains...Southwest OK...
Scattered storms are expected to form around 21Z from central and
southeast NM into parts of west TX, where heating is strongest south
of the front. Hail is possible with the NM cells, as well as into
the South Plains. A brief tornado cannot be ruled out near peak
heating, near the boundary, and before cells grow upscale into a
possible MCS. The greatest potential for damaging winds will likely
be along the boundary, extending into northwest TX, as storms move
along it, aided by strong east/northeast surface winds just north of
the boundary. A few storms may remain strong to severe into far
southwest OK, before the air mass overturns with more widespread
precipitation.

...Eastern IA...northern IL...southern WI...
Upstream heating of a 50s dewpoint air mass and increasing southerly
winds ahead of the surface low will result in an axis of around 1000
J/kg MLCAPE by afternoon across IA/IL/WI. Forecast soundings show
some capping around 700 mb, but lift near the low track is expected
to support thunderstorm development, which will be centered over the
tri-state area. While winds in the mid and upper levels will not be
particularly strong (short hodographs), low-level veering of the
winds with height may support rotating storms with marginal hail,
wind, or a brief tornado (especially over WI where LCLs will be
lower).

..Jewell/Karstens.. 04/22/2019

$$
        

Day 3

Day 4