SPC AC 182000

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0300 PM CDT Tue Jun 18 2019

   Valid 182000Z - 191200Z

   ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM WEST TX
   INTO KS...

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
   THE PLAINS AND MIDDLE ATLANTIC...

   ...SUMMARY...
   Scattered severe thunderstorms are likely across parts of the
   central and southern Great Plains in multiple rounds this afternoon
   through tonight. Other severe thunderstorms are expected across the
   Mid-Atlantic region and parts of the Southeast.

   ...20z Update...

   Remnants of long-lived MCS are progressing along the I-70 corridor
   across KS. Leading edge of this activity is beginning to intensify
   over northeast KS which may propagate a bit farther downstream than
   earlier anticipated. Will expand higher severe probs across portions
   of TOP CWA to account for these trends.

   Strong boundary-layer heating across the High Plains has contributed
   to near-dry adiabatic low-level lapse rates from southeast CO into
   west TX. Convection will gradually expand in areal coverage along
   this corridor over the next few hours before spreading into the ENH
   Risk region.

   ..Darrow.. 06/18/2019

   .PREV DISCUSSION... /ISSUED 1152 AM CDT Tue Jun 18 2019/

   ...Kansas...
   An MCV will continue to drift generally eastward across
   western/central Kansas through the afternoon and evening. A trend of
   thinning/increasingly scattered cloud cover should occur through the
   afternoon, aided by a modest MCV-peripheral dry slot. Expectations
   are for more of a southeasterly low-level wind component to
   materialize across central Kansas by mid/late afternoon, while
   enhanced mid-level winds otherwise spread eastward across the
   southern half of Kansas. Thunderstorms should initially intensify
   across central/south-central Kansas by mid-afternoon, with moderate
   buoyancy and sufficient deep-layer shear/modest overall forcing
   likely being conducive for semi-discrete supercells, at least for a
   few hours duration. A few tornadoes will be possible aside from
   severe hail/wind as storms spread east-southeastward toward and
   across the I-35/I-135 corridor through late afternoon and
   early/mid-evening.

   ...Oklahoma/Texas Panhandle to west/southwest Texas...
   Timing of the peak/most-certain severe risk is a bit questionable
   across parts of this region, but the potential exists for a
   sub-regional corridor to be impacted by multiple rounds of severe
   thunderstorms. At the very least, a conditional severe/supercell
   risk will exist as early as mid/late afternoon across the Texas
   Panhandle/Low Rolling Plains and western Oklahoma within a very
   unstable environment. However, modest convergence and a tendency for
   mid-level warming casts some uncertainty. At the very least, storms
   are likely to move into/across the region later this evening with an
   appreciable damaging wind/hail risk via one or more well-organized
   clusters.

   Farther south, a couple supercells should form over the higher
   terrain of the TX Trans-Pecos with a primary risk of large hail.
   Minor mid-level height rises suggest robust MLCIN will hold east of
   the Pecos River, limiting the spatial extent of this threat. A
   separate area of thunderstorms may form near the intersection of the
   dryline and residual outflow boundary trailing from the central
   Texas MCS. A deeply mixed boundary layer should support a few
   supercells that might organize into a cluster this evening. Large
   hail and severe wind should be the primary threats.

   ...CO Front Range/south-central High Plains...
   Scattered thunderstorm development is likely over the Raton Mesa and
   other parts of Southeast Colorado by peak heating as a minor
   mid-level impulse in Utah crosses the southern Rockies. Amid 30-40
   kt 500-mb westerlies, this activity should spread east and impinge
   on richer boundary-layer moisture in the Texas Panhandle this
   evening. At least on an isolated basis, supercells capable of large
   hail and possibly some tornado/damaging wind risk can be expected as
   storms spread east/southeastward.

   ...Mid-Atlantic States/Delmarva...
   An area of organized severe potential is apparent across southeast 
   PA, NJ, northern MD, and DE ahead of an MCV/weak surface cyclone
   currently over western PA. Here, some enlargement to low-level
   hodographs in conjunction with moderate boundary-layer heating of
   low 70s dew points should support a risk for a few supercells
   capable of a tornado or two and damaging winds/some hail. Refer to
   Mesoscale Discussion 1115 for additional short-term details.

   ...Central Gulf Coast to Carolinas...
   A belt of 20-30 kt west-southwesterly flow will persist amid
   afternoon MLCAPE of 1000-2000 J/kg. This should again foster a
   threat for mainly locally damaging wind as numerous multicells occur
   through this afternoon.

   ...Montana/Northern High Plains...
   Isolated strong to severe semi-low-topped thunderstorms will be
   possible this afternoon into evening within a modestly
   moist/unstable environment ahead of an
   amplifying/southeastward-moving mid-level shortwave trough.
   Well-mixed boundary layers could yield severe-caliber wind gusts
   along with some localized/marginal hail potential.

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