SPC AC 251948

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0248 PM CDT Sat May 25 2019

   Valid 252000Z - 261200Z

   ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
   THE SOUTHERN/CENTRAL PLAINS...

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE MID MS
   VALLEY TO THE OH VALLEY...

   ...SUMMARY...
   Severe thunderstorms are likely this afternoon into tonight from the
   Texas and Oklahoma Panhandles into western/northern Oklahoma and
   Kansas. Other severe storms are expected across the upper Ohio River
   Valley and Allegheny Plateau, and possibly other portions of the
   Midwest.

   ...20z Update...

   Minor changes have been made to 1630z outlook, namely to extend
   higher severe probs across northern MO into western IL. While
   short-term subsidence is currently noted across the Midwest in the
   wake of OH Valley short-wave trough, buoyancy is expected to develop
   northeast across MO into IL into the late afternoon. With time
   convection should develop along this corridor, possibly similar to
   latest CAMs. Given the strength of the shear across this region,
   some severe threat is expected with this activity. For these
   reasons, SLGT Risk has been extended into the Mid-MS Valley.

   Elsewhere, expanding cluster of thunderstorms is spreading northeast
   across the TX Panhandle. Other supercells should evolve with time
   and this later activity could pose more of a tornado risk, along
   with very large hail.

   ..Darrow.. 05/25/2019

   .PREV DISCUSSION... /ISSUED 1128 AM CDT Sat May 25 2019/

   ...OH Valley...
   Morning satellite imagery shows a well-defined shortwave trough
   moving rapidly eastward across IL.  Strong heating is occurring
   ahead of this feature across much of IN/OH.  Surface dewpoints in
   the upper 60s and afternoon high temperatures well into the 80s will
   yield a corridor of MLCAPE values around 1500 J/kg.  Present
   indications are that thunderstorms will intensify this afternoon
   across central IN and track into much of OH.  Meanwhile, more
   isolated strong storms will form across parts of western NY/PA. 
   Strong flow aloft and steep low-level lapse rates suggest a risk of
   damaging wind gusts in the strongest cells across this region today.
    A few storms may also become supercells with a risk of hail or
   perhaps a tornado.

   ...Southern/Central Plains...
   Fast southwesterly flow aloft persists across west TX into adjacent
   parts of OK/KS today, with only subtle large-scale forcing
   mechanisms noted.  One such feature is apparent in water vapor
   imagery near the Big Bend region.  This shortwave trough will affect
   west TX by mid afternoon.  Ample low level moisture is in place
   across this area with dewpoints in the mid 60s as far west as
   eastern NM.  Current indications are that storms will initially form
   near the diffuse dryline along the NM/TX border, with other activity
   developing northeastward into parts of southwest KS through the
   afternoon.  Forecast soundings indicate that supercell structures
   will be the prominent mode - at least initially.  Very large hail
   and damaging wind gusts are the main risks.  This evening, the risk
   of tornadoes is expected to increase as the low level jet
   strengthens somewhat over the eastern TX Panhandle and western OK.

   Storms will spread east-northeastward across much of KS this
   evening, and into parts of MO tonight.  These storms will maintain a
   risk of hail and damaging wind gusts.

   ...Northern Great Basin...
   A strong upper trough is present today over northern CA and western
   NV, with  a shortwave trough rotating northeastward across NV. 
   Rather fast flow aloft extends across much of the Great Basin, with
   scattered afternoon thunderstorms expected.  Several 12z CAM
   solutions indicate a risk of a few stronger updrafts tracking from
   northern UT into parts of southeast ID and western WY.  Forecast
   soundings suggest sufficient CAPE above inverted-v profiles -
   favorable for gusty/damaging wind gusts.  CAM guidance also suggests
   a few bowing structures are possible.

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   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z