SPC AC 021920

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0220 PM CDT Mon May 02 2022

   Valid 022000Z - 031200Z

   ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS MUCH OF
   NORTHERN OKLAHOMA...

   ...SUMMARY...
   Intense severe thunderstorms are expected across portions of
   northern Oklahoma and far southern Kansas this afternoon and
   evening. Tornadoes and damaging winds, and large hail are all
   likely.

   ...Discussion...
   A shortwave trough is currently moving east across KS, with midlevel
   temperature gradient into far northern OK. A cold front is now
   surging southeast across the TX Panhandle and into western OK, with
   a dryline extending from southwest OK into northwest TX. Meanwhile,
   a warm front, reinforced by earlier precipitation, is currently
   draped from northwest into central and eastern OK. The cap is
   currently weak across the warm sector, and continued heating as well
   as warm advection should allow the warm front to mix northward
   through the evening.

   Shear is already favorable for supercells and tornadoes, with
   effective SRH in excess of 300 m2/s2 near the warm front. Storm mode
   will continue to play a pivotal role regarding tornado potential,
   with threat maximized with supercells that can either 1) keep up
   with the surging cold front or 2) develop ahead of the front and/or
   expected squall line. Even if storm mode becomes linear, strong
   instability and shear will favor QLCS tornadoes, especially with any
   segments of the line that can become more north-south oriented,
   rather than east-west (which may maximized undercutting outflow).
   Otherwise, significant damaging wind gusts are expected with storms
   that travel eastward across northern and northeast OK through
   evening.

   For more information, reference mesoscale discussion 620, 621, 622
   and tornado watch 171.

   ..Jewell.. 05/02/2022

   .PREV DISCUSSION... /ISSUED 1126 AM CDT Mon May 02 2022/

   ...KS/OK...
   Morning water vapor imagery shows a fast-moving compact upper trough
   moving across the Rockies, with an associated 60+ knot mid-level
   speed max tracking quickly into KS/OK.  At the nose of this jet, a
   rather deep surface low is over southwest KS.  Strong southerly low
   level winds are present in the warm sector of the low, but moisture
   return is complicated by multiple clusters of remnant convection and
   outflow boundaries.  Rich moisture has returned to southern OK to
   the south of the outflow boundaries, and is still expected to make a
   rapid northward return this afternoon.

   Present indications are that multiple convective scenarios will play
   out in close areal/temporal proximity today over northwest OK. 
   Initial storms may be along the bent-back portion of the low-level
   moisture plume over southwest KS.  These storms will be in a very
   favorable low-level shear environment for supercell structures and
   possibly tornadoes, but early initiation (around 18z) may be before
   sufficient low-level destabilization can fully occur.  Nevertheless,
   a few severe storms are expected in this regime that track
   east-northeastward into south-central KS this afternoon and evening.

   Just to the south and east of this setup, intense discrete
   supercells are expected to form by mid-afternoon along the dryline
   near or just south of the triple-point along the KS/OK border. 
   These storms will have the greatest risk of significant tornadoes
   and very large hail, assuming they can persist ahead of the
   approaching cold front. This threat area is depicted in the 15%
   tornado risk area. Several CAM solutions suggest that convection
   will attempt to form farther south along the dryline this afternoon,
   but few are able to sustain this activity.  While this risk of
   thunderstorm development is lower than farther north, it is non-zero
   and any storm that can mature would pose similar risks of
   significant severe weather including tornadoes.

   A strong cold front will surge into central OK by late afternoon,
   undercutting existing storms and becoming a focus for the
   development of a squall line.  These storms will also pose a risk of
   rather widespread damaging wind gusts, very large hail, and a few
   tornadoes through the evening.  Storms may persist well into the
   night into the Red River valley.

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