Apr 22, 2019 0600 UTC Day 1 Convective Outlook
Updated: Mon Apr 22 04:41:55 UTC 2019 (20190422 1200Z Day 1 shapefile | 20190422 1200Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20190422 1200 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SLIGHT 28,347 535,690 Lubbock, TX...Hobbs, NM...Levelland, TX...Snyder, TX...Vernon, TX...
MARGINAL 83,892 5,897,581 Madison, WI...Rockford, IL...Wichita Falls, TX...Midland, TX...Davenport, IA...
Probabilistic Tornado Graphic
20190422 1200 UTC Day 1 Tornado Probabilities Graphic
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.
Day 1 Tornado Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
2 % 60,102 4,708,374 Madison, WI...Lubbock, TX...Rockford, IL...Cedar Rapids, IA...Davenport, IA...
Probabilistic Damaging Wind Graphic
20190422 1200 UTC Day 1 Damaging Wind Probabilities Graphic
Probability of damaging thunderstorm winds or wind gusts of 50 knots or higher within 25 miles of a point.
Hatched Area: 10% of greater probability of wind gusts 65 knots or greater within 25 miles of a point.
Day 1 Wind Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
15 % 29,538 542,362 Lubbock, TX...Hobbs, NM...Levelland, TX...Snyder, TX...Vernon, TX...
5 % 85,276 6,369,155 Milwaukee, WI...Madison, WI...Rockford, IL...Cedar Rapids, IA...Norman, OK...
Probabilistic Large Hail Graphic
20190422 1200 UTC Day 1 Large Hail Probabilities Graphic
Probability of hail 1" or larger within 25 miles of a point.
Hatched Area: 10% or greater probability of hail 2" or larger within 25 miles of a point.
Day 1 Hail Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
15 % 18,371 479,477 Lubbock, TX...Hobbs, NM...Levelland, TX...Snyder, TX...Lovington, NM...
5 % 88,919 5,195,846 Madison, WI...Rockford, IL...Cedar Rapids, IA...Wichita Falls, TX...Midland, TX...
   SPC AC 220441

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

   Valid 221200Z - 231200Z


   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.

   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

   ...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

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