SPC AC 211729

   Day 2 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1229 PM CDT Thu Mar 21 2019

   Valid 221200Z - 231200Z

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE
   SOUTHERN HIGH PLAINS FRIDAY AFTERNOON AND EVENING...

   ...SUMMARY...
   Isolated severe thunderstorms are possible across the southern High
   Plains from Friday afternoon through early evening.

   ...Southern High Plains Vicinity...

   A shortwave trough will shift eastward across the southern Rockies
   to the Plains on Friday. Ahead of this feature, modest boundary
   layer moisture will be transported north/northwest from the western
   Gulf of Mexico. Surface dewpoints in the low 50s are forecast across
   much of west TX into far eastern NM with decreasing values further
   north toward southeast CO and southwest KS. Ongoing showers and
   cloud cover will initially limit destabilization, but with as the
   shortwave shifts eastward, cooling aloft will result in steepening
   midlevel lapse rates and MLCAPE peaking around 1000 J/kg is possible
   in a narrow corridor across the Marginal risk area. Strong height
   falls during the afternoon and evening will result in a weak lee
   trough across eastern CO/NM with a Pacific cold front shifting east
   across the southern High Plains during the evening and overnight
   hours. 

   Shear profiles will be strongest/most favorable for
   organized/rotating convection further north where backed low level
   flow closer to the weak lee low will exist. However, moisture will
   be marginal across this area and storms may be higher-based.
   Additionally, hi-res guidance suggests line segments are most likely
   as the Pacific front quickly shifts eastward and weak instability
   limits stronger updraft potential. Convection may be able to remain
   cellular a bit longer further south where forcing mechanisms will be
   more subtle and instability/moisture modestly better. However, shear
   profiles become weaker in the low levels. As a result, storms may
   also be fewer with southward extent. Overall, steep midlevel lapse
   rates coupled with modest instability/shear will result in at least
   a marginal threat for hail and wind, and a tornado can not be ruled
   out. 

   As convection shifts eastward across the OK/TX Panhandles/TX South
   Plains toward western OK overnight, severe threat should wane as
   convection becomes elevated with time as the boundary layer
   stabilizes with loss of heating. While steeper lapse rates do
   overspread the Panhandles and western OK overnight, instability is
   very weak and even small hail from elevated convection appears
   unlikely.

   ...MAXIMUM RISK BY HAZARD...
   Tornado:   2%     - Marginal
   Wind:      5%     - Marginal
   Hail:      5%     - Marginal

   ..Leitman.. 03/21/2019

   CLICK TO GET WUUS02 PTSDY2 PRODUCT

   NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 0600Z