Skip Navigation Links 
NOAA logo-Select to go to the NOAA homepage NOAA's National Weather Service   Select to go to the NWS homepage
Storm Prediction Center
navigation bar left  
  navigation bar end cap is the U.S. Government's official Web portal to all Federal, state and local government Web resources and services.

Mesoscale Discussion 1013
< Previous MD         Next MD >
MD 1013 graphic

   Mesoscale Discussion 1013
   NWS Storm Prediction Center Norman OK
   0232 PM CDT Tue Jun 13 2017

   Areas affected...North-central Nebraksa...East-central South
   Dakota...Southeast North Dakota

   Concerning...Severe potential...Watch likely 

   Valid 131932Z - 132030Z

   Probability of Watch Issuance...95 percent

   SUMMARY...A severe threat is likely to develop this afternoon from
   central Nebraska north northeastward into southeastern North Dakota
   and west-central Minnesota. Large hail and wind damage will be
   possible after cells initiate but a tornado threat should also
   develop as cells mature. A weather watch will likely be needed
   across the region by 20Z.

   DISCUSSION...The latest surface analysis shows a 999 mb low over
   north-central Nebraska with a cold front extending
   south-southwestward from the low. Surface winds are backed across
   much of eastern South Dakota where low-level moisture is maximized
   with surface dewpoints in the lower to mid 70s F. This is
   contributing to a pocket of strong instability in eastern South
   Dakota and northeastern Nebraska where the RAP is estimating MLCAPE
   values in the 3000 to 4000 J/kg range. In addition, water vapor
   imagery shows a shortwave trough over the central and northern
   Rockies. A vorticity maxima associated with the shortwave trough is
   analyzed by the RAP across western Nebraska. As this feature moves
   across the central and northern Plains this afternoon, large-scale
   ascent will support the development of numerous thunderstorms along
   the cold front and to the northeast of the surface low into
   southeastern North Dakota and west-central Minnesota.

   Forecast soundings along this corridor show favorable wind profiles
   for supercells with strong speed shear in the low to mid-levels with
   0-6 km shear forecast to be in the 35 to 45 kt range. This combined
   with very steep mid-level lapse rates exceeding 8.5 C/km across
   parts of the MCD area will be favorable for large hail with
   supercells. Hailstones of greater than 2 inches in diameter will be
   possible within the strongest cores. Cells that do not form into
   supercells may still be severe with a threat for hail and wind
   damage. As the low-level jet increases in strength late this
   afternoon and as the storms become mature, a tornado threat will
   also be possible across the MCD area. The most favorable area for
   tornado development could be across northeastern South Dakota,
   southeastern North Dakota and west-central Minnesota.

   ..Broyles/Hart.. 06/13/2017

   ...Please see for graphic product...


   LAT...LON   44779673 43899777 42009819 41229878 40989984 41040067
               41620126 42560114 44610060 45909999 46979834 47239723
               47129619 46629560 45949546 45129631 44779673 

Top/All Mesoscale Discussions/Forecast Products/Home
Weather Topics:
Watches, Mesoscale Discussions, Outlooks, Fire Weather, All Products, Contact Us

NOAA / National Weather Service
National Centers for Environmental Prediction
Storm Prediction Center
120 David L. Boren Blvd.
Norman, OK 73072 U.S.A.
Page last modified: June 13, 2017
Information Quality
Privacy Policy
Freedom of Information Act (FOIA)
About Us
Career Opportunities