SPC AC 262000

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0300 PM CDT Mon Jun 26 2017

   Valid 262000Z - 271200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PART OF
   NORTHERN AND CENTRAL KANSAS INTO A SMALL PART OF EASTERN COLORADO...

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS SURROUNDING THE
   SLIGHT RISK AREA IN THE CENTRAL TO SOUTHERN PLAINS...

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE
   PACIFIC NORTHWEST AND NORTHERN ROCKIES...

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS NORTHERN
   FL AND SOUTHEAST GA...

   ...SUMMARY...
   Thunderstorms with severe hail and strong wind gusts are possible
   late this afternoon into evening across the Pacific Northwest and
   Northern Rockies in addition to parts of the Great Plains.  Other
   strong storms may occur along the coastal southeast States.

   ...Eastern CO/southwest NE/northern and central KS...
   Trends in visible satellite imagery and mosaic radar imagery showed
   some increase in thunderstorm development across far southern NE
   into northern KS and eastern CO.  Given the presence of moderate
   instability and effective bulk shear of 30-40 kt, additional
   organized storms appear a concern through the afternoon into the
   evening.  Last several runs of the HRRR suggest a greater clustering
   of storms may occur from northern KS to the south-southeast reaching
   the Wichita, KS area this evening.  This outlook has increased the
   severe hail and damaging wind probabilities resulting in a Slight
   risk area in parts of KS to eastern CO.  For additional short-term
   guidance, refer to mesoscale discussion 1152.

   ...Part of south-central WA...
   Given ongoing convection and some thunderstorms developing in lee of
   the southern WA Cascades, steep low-level lapse rates and DCAPE
   exceeding 1000 J/kg suggest locally strong wind gusts will be
   possible.  This outlook has expanded the marginal severe wind threat
   westward some to include more of south-central WA.

   ..Peters.. 06/26/2017

   .PREV DISCUSSION... /ISSUED 1144 AM CDT Mon Jun 26 2017/

   ...Pacific Northwest/northern Rockies...
   Gradually strengthening westerlies aloft are expected over the
   region today. This will be as an upper low just off the coast of
   northern CA continues east-northeastward and a trough amplifies over
   British Columbia, while a convectively related disturbance also
   shifts eastward from southeast WA/northern ID into MT. It seems
   likely that thunderstorms will increase this afternoon especially
   east of the Cascades across central/eastern OR into adjacent
   ID/southeast WA, in addition to parts of west-central MT.
   Strengthening winds aloft/vertical shear will help support some
   sustained east/northeastward-moving storms. Isolated instances of
   locally damaging winds will be possible with the strongest storms
   along with some hail, particularly across parts of OR into ID where
   somewhat greater moisture/destabilization is expected. 

   ...Central Plains/southern High Plains...
   Under the glancing influence of the Upper Midwest/Great Lakes
   upper-level trough, isolated to widely scattered thunderstorms are
   likely to develop by mid/late afternoon within a corridor from
   southern NE southward into KS. Although mid-level lapse rates are
   not particularly steep by late-June standards, gradually returning
   moisture, moderate buoyancy, and supercell-favorable wind profiles
   (in the presence of strong northwesterly flow aloft) should allow
   for isolated severe thunderstorms capable of severe hail/locally
   damaging winds as these storms spread southeastward through the late
   afternoon and evening hours.

   Elsewhere, as a moist upslope flow regime persists, other storms are
   likely to develop/intensify across along the southeast CO/northeast
   NM Raton Mesa vicinity and higher terrain of interior NM. In the
   presence of moderate buoyancy and 30-35 kt of effective shear, some
   of the stronger storms will be capable of hail.

   Farther south, one or more remnant MCVs may refocus afternoon
   redevelopment, including the possibility of a few stronger storms,
   across parts of the TX Edwards Plateau and nearby Transpecos
   vicinity.

   ...North FL/coastal GA...
   As weak height falls spread toward the region today, a moist
   environment and sea breeze circulations in vicinity of a
   stalled/slow-moving front may allow for a few stronger storms this
   afternoon capable of downbursts.

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