Storm Prediction Center Mesoscale Discussion 498

   Mesoscale Discussion 0498
   NWS Storm Prediction Center Norman OK
   0122 AM CDT Sun Apr 20 2025

   Areas affected...Eastern Oklahoma...Northwest Arkansas...Far
   Southwest Missouri

   Concerning...Tornado Watch 152...

   Valid 200622Z - 200715Z

   The severe weather threat for Tornado Watch 152 continues.

   SUMMARY...A threat for severe wind gusts and tornadoes will move
   across eastern Oklahoma and into northwest Arkansas over the next
   few hours. The threat is expected to eventually affect far southwest
   Missouri, where weather watch issuance is possible.

   DISCUSSION...The latest hi-resolution radar imagery from Tulsa shows
   a north-to-south oriented severe line segment across eastern
   Oklahoma. Ahead of the line, surface dewpoints are in the 60s F.
   Near the moist axis, an axis of instability is analyzed by the RAP
   with MLCAPE around 1000 J/kg range. Co-located with the instability
   axis, the RAP is analyzing a 50 to 60 knot 700 mb jet from northeast
   Texas into southeast Oklahoma. This line of storms is located near
   the nose of this jet max. Short-term model forecasts strengthen the
   jet max and move it into eastern Oklahoma over the next few hours.
   This will provide lift and strong shear favorable for severe
   maintenance.

   The latest WSR-88D VWP from Fort Smith has 0-6 km shear around 65
   knots, with 0-3 km storm-relative helicity near 550 m2/s2. This will
   continue to support a QLCS with embedded rotating elements. These
   stronger storms will be associated with severe wind gusts, and
   potentially tornadoes. The threat is expected to persist for several
   more hours. The line should eventually move into northwest Arkansas
   and far southwest Missouri where instability will be more limited.

   ..Broyles.. 04/20/2025

   ...Please see www.spc.noaa.gov for graphic product...

   ATTN...WFO...LZK...SGF...SHV...TSA...OUN...

   LAT...LON   36759496 36469540 36109556 35429576 34399591 34119581
               34019538 34419453 35089380 35649329 35999305 36279305
               36629323 36809384 36759496 

   MOST PROBABLE PEAK TORNADO INTENSITY...120-150 MPH
   MOST PROBABLE PEAK WIND GUST...55-70 MPH
   MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN