Apr 22, 2019 2000 UTC Day 1 Convective Outlook

Categorical Graphic 20190422 2000 UTC Day 1 Outlook Graphic
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SLIGHT 33,158 596,356 Lubbock, TX…Roswell, NM…Hobbs, NM…Levelland, TX…Vernon, TX…
MARGINAL 95,834 7,913,323 Milwaukee, WI…Madison, WI…Rockford, IL…Cedar Rapids, IA…Norman, OK…
Probabilistic Tornado Graphic 20190422 2000 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 % 65,163 5,795,894 Madison, WI…Lubbock, TX…Rockford, IL…Cedar Rapids, IA…Davenport, IA…
Probabilistic Damaging Wind Graphic 20190422 2000 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 % 32,875 610,844 Lubbock, TX…Roswell, NM…Hobbs, NM…Levelland, TX…Vernon, TX…
5 % 95,169 7,903,440 Milwaukee, WI…Madison, WI…Rockford, IL…Cedar Rapids, IA…Norman, OK…
Probabilistic Large Hail Graphic 20190422 2000 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 % 26,908 577,783 Lubbock, TX…Roswell, NM…Hobbs, NM…Plainview, TX…Levelland, TX…
5 % 98,501 6,308,801 Madison, WI…Rockford, IL…Cedar Rapids, IA…Norman, OK…Wichita Falls, TX…
   SPC AC 221947

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0247 PM CDT Mon Apr 22 2019

   Valid 222000Z - 231200Z


   Scattered severe thunderstorms capable of mainly hail and damaging
   winds are possible from southeast New Mexico into parts of west
   Texas and southwest Oklahoma late this afternoon and evening.
   Isolated severe storms will also be possible across parts of
   southern Wisconsin, eastern Iowa, and northern Illinois through the
   evening hours.


   Convection has begun to increase in intensity across eastern IA
   where strong heating and modest increases in boundary layer moisture
   has resulted in weak destabilization. An 18z RAOB from DVN indicated
   some weak capping around 850mb but this should be overcome by
   increased ascent spreading over the tri-state region currently. 
   Steep midlevel lapse rates and deep boundary layer mixing will
   support a few strong to severe storms capable of marginal hail and
   some locally damaging wind gusts.  No changes have been made to the
   previous outlook. For more info, see recently issued MCD 419.


   Stronger ascent associated with southeastward progressing upper low
   over the lower CO Valley will continue to spread northeast into the
   southern Rockies/High Plains vicinity late this afternoon into this
   evening. Towering CU over higher terrain in NM and northern Mexico
   indicate environment is becoming more favorable for thunderstorm
   development in the next few hours. A corridor of storms from
   southeast NM into southwest OK ahead of a surface front still
   appears favorable for isolated to scattered severe storms through
   this evening. Large hail and damaging wind will be the main concerns
   with this threat. Ongoing forecast remains on track and no changes
   have been made.

   ..Leitman.. 04/22/2019

   .PREV DISCUSSION... /ISSUED 1116 AM CDT Mon Apr 22 2019/

   A couple of mid-level waves will provide impetus for potential
   severe weather later today - one currently centered over western
   Iowa that will migrate northeastward toward Lower Michigan and
   another centered over the Lower Colorado River Valley that will
   migrate southeastward into northwestern Mexico.  At the surface, a
   low over northeastern Iowa will migrate eastward across southern
   Wisconsin and into northern Lower Michigan today - generally along a
   WSW-ENE oriented surface warm front.  A cold front will extend
   south-southwest from this low across Missouri and Oklahoma,
   ultimately transitioning into a stationary boundary across the Texas
   South Plains and vicinity.  Lee surface troughing will extend from
   south-central New Mexico into far west Texas throughout the forecast

   ...Eastern New Mexico eastward through central Oklahoma...
   Morning satellite/observations indicate limited solar insolation
   beneath a widespread cirrus shield.  However, gradual low-level
   moistening was occurring across portions of southeastern NM and far
   west Texas near the surface trough axis.  Surface flow was beginning
   to take on a more easterly component north of the front across the
   Texas South Plains, and these trends should continue throughout the

   Later today, a shortwave trough currently over northern Mexico will
   eject northeastward toward west Texas.  Ascent associated with that
   feature, lift along the stationary front, and low-level upslope will
   result in scattered to numerous thunderstorm development.  Though
   low-level wind fields should be weak, steep mid-level lapse rates
   and strong deep shear will result in organized storms capable of
   hail and damaging wind gusts.  Storms should grow upscale into one
   or two linear complexes and forward-propagate eastward along/near
   the surface boundary especially within the Slight Risk area.  A few
   storms will also develop into portions of southwestern Oklahoma and
   pose a hail risk.  The threat should mostly be diurnally driven,
   although some hail/wind risk may persist overnight given forecast
   strengthening of a low-level jet across west Texas.

   ...Wisconsin, Illinois, and far eastern Iowa...
   Continued surface heating along and ahead of the surface low and
   mid-level wave will result in a few thunderstorms this afternoon
   that will spread eastward across the Marginal Risk area.  Modest
   mid-level lapse rates and mid-50s F dewpoints will tend to limit
   buoyancy.  However, the deepening low will foster slightly backed
   low-level flow later today, which may result in a few supercellular
   structures.  Damaging winds and perhaps a tornado or two are
   possible with this activity - especially with any updrafts that can
   favorably interact with the warm front over central Wisconsin.

   Later tonight, forcing associated with the amplifying mid-level wave
   may result in a very isolated damaging wind threat in northern Lower
   Michigan, although it is unclear if surface-based convective
   updrafts will persist across cold waters of Lake Michigan.