SPC AC 281619

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1119 AM CDT Mon May 28 2018

   Valid 281630Z - 291200Z

   ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM SOUTHEAST
   WYOMING AND NORTHEAST COLORADO INTO SOUTHWEST NEBRASKA...WESTERN
   KANSAS...INTO THE TEXAS PANHANDLE...

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
   THE CENTRAL PLAINS...AND OVER PORTIONS OF GEORGIA AND EASTERN
   ALABAMA...

   ...SUMMARY...
   Severe thunderstorms with very large hail, wind damage and a few
   tornadoes are expected across parts of the Great Plains.  A few
   tornadoes will also be possible over parts of Georgia and Alabama in
   conjunction with Alberto.

   ...Central Plains...
   A persistent upper low is centered over UT, with a mid-level jet
   wrapping around the low across AZ/NM into CO/NM.  Water vapor
   imagery shows a significant shortwave trough embedded in the
   stronger flow over northeast NM.  This feature will rotate into
   central CO later this afternoon, providing the lift for an active
   severe weather event across parts of the central Plains states.

   ...CO...
   Latest visible satellite imagery and surface analysis shows a
   boundary extending from southwest NE into eastern CO.  Low clouds on
   the north side of this boundary are slowing eroding, and should
   result in a corridor of moderate CAPE later today (dewpoints in the
   upper 50s and steep mid level lapse rates).  12z CAM solutions are
   consistent in the development of thunderstorms along/north of this
   boundary from just southeast of DEN into northeast CO.  Forecast
   soundings suggest a favorable combination of thermodynamics and deep
   layer shear of 50-60 knots, supporting supercells.  Enhanced
   low-level shear will also be favorable of a few tornadoes.  Have
   introduced a small 10% tornado risk area for this threat.  Very
   large hail and damaging winds will also be possible in this area.

   ...Western KS to TX Panhandle...
   Farther east, strong heating and ample CAPE will result in a line of
   thunderstorms roughly along the CO/KS border southward into the TX
   panhandle this afternoon.  These storms will rapidly become severe,
   capable of very large hail and damaging winds.  Isolated tornadoes
   are also possible in more persistent supercells.  These storms are
   expected to merge into a broken line, with an enhanced wind damage
   threat through the evening.

   ...GA/AL...
   The center of Alberto will track across the FL Panhandle and into AL
   today.  Considerable heating is occurring to the east of the center
   across parts of GA and southeast AL, where dewpoints are in the
   low/mid 70s.  CAM guidance suggests that scattered thunderstorms
   will form in this corridor later today, with forecast soundings
   indicating sufficient low level shear/helicity for some risk of
   tornadoes in the more persistent updrafts.  Have therefore upgraded
   this area to SLGT risk.

   ..Hart/Elliott.. 05/28/2018

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