Skip Navigation Links weather.gov 
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


 
USA.gov is the U.S. Government's official Web portal to all Federal, state and local government Web resources and services.

Mesoscale Discussion 615
< Previous MD         Next MD >
MD 615 graphic

   MESOSCALE DISCUSSION 0615
   NWS STORM PREDICTION CENTER NORMAN OK
   0137 PM CDT SUN MAY 18 2014

   AREAS AFFECTED...PARTS OF MT...NE WY...FAR WRN DAKOTAS

   CONCERNING...SEVERE POTENTIAL...WATCH LIKELY 

   VALID 181837Z - 182000Z

   PROBABILITY OF WATCH ISSUANCE...80 PERCENT

   SUMMARY...THUNDERSTORMS WILL CONTINUE TO DEVELOP OVER THE HIGHER
   TERRAIN FROM SW INTO CENTRAL MT. SOME OF THESE STORMS MAY PRODUCE
   GUSTY WINDS AND SMALL HAIL. FURTHER EAST INTO SE MT...NE WY AND THE
   WRN DAKOTAS...SEVERE STORMS ARE EXPECTED TO EVOLVE LATER THIS
   AFTERNOON AND EVENING WITH DAMAGING WINDS AND HAIL BEING THE MAIN
   THREATS...BUT A TORNADO OR TWO ALSO IS POSSIBLE. A WW WILL LIKELY BE
   NEEDED IN THE NEXT 1-2 HOURS.

   DISCUSSION...THUNDERSTORMS WERE DEVELOPING OVER THE HIGHER TERRAIN
   FROM SW INTO CENTRAL MT EARLY THIS AFTERNOON. LACK OF STRONGER
   INSTABILITY AND LOW LEVEL MOISTURE SHOULD LIMIT THE OVERALL
   INTENSITY OF THESE STORMS...BUT STEEP LAPSE RATES AND FAST STORM
   MOTION COULD YIELD A STRONGER WIND GUST IN ADDITION TO SOME SMALL
   HAIL. 

   THE MAIN SEVERE THREAT IS EXPECTED TO OCCUR FURTHER EAST ACROSS
   PARTS OF SE MT INTO THE WRN DAKOTAS AND NE WY LATER THIS AFTERNOON
   AND EVENING. VIS SATELLITE IMAGERY SHOWED SOME CUMULUS DEVELOPING
   BOTH NEAR HIGHER TERRAIN AND OVER THE HIGH PLAINS. AS THE UPPER
   SHORTWAVE IMPULSE CURRENTLY OVER ERN ORE/WRN ID CONTINUES TO PIVOT
   E/NE...DEEP LAYER FORCING FOR ASCENT WILL INCREASE ACROSS THE
   REGION. FURTHERMORE...AN EWD ADVANCING COLD FRONT AND DEEPENING LEE
   SFC LOW WILL PROVIDE FOCUS FOR STRONG TO SEVERE THUNDERSTORMS
   DEVELOPMENT BY 20-21Z IN THE VICINITY OF LWT TO BIL. LOW LEVEL
   MOISTURE APPEARS TO BE PERHAPS A LITTLE BETTER THAN PREVIOUS MODEL
   INDICATIONS...WITH DEW POINTS CLIMBING INTO THE LOW 50S AT OF 18Z.
   WITH CONTINUED SFC HEATING...SBCAPE VALUES NEAR 1500 J/KG /PERHAPS
   POCKETS APPROACHING 2000 J PER KG/ ARE EXPECTED. STEEP MID LEVEL
   LAPSE RATES AND EFFECTIVE SHEAR GREATER THAN 30 KTS WILL ALLOW FOR
   SOME ROTATING STRUCTURES AND/OR BOWING SEGMENTS. EVEN WITH BETTER
   THAN EXPECTED LOW LEVEL MOISTURE...TEMPERATURE-DEW POINT SPREADS
   WILL STILL BE ON THE ORDER OF 20-30 DEGREES F AND STRONG DOWNBURST
   WINDS WILL BE THE MAIN THREAT. ADDITIONALLY...STEEP MIDLEVEL LAPSE
   RATES NEAR 7.5 DEG C/KM AND COLD TEMPERATURES ALOFT WILL SUPPORT
   SOME INSTANCES OF LARGE HAIL. A TORNADO OR TWO MAY BE POSSIBLE
   TOWARD EVENING WHEN AN INCREASING LOW LEVEL JET WILL MAXIMIZE LOW
   LEVEL SHEAR PROFILES AND LCL HEIGHTS BEGIN TO LOWER.

   ..LEITMAN/HART.. 05/18/2014


   ATTN...WFO...BIS...UNR...CYS...BYZ...GGW...RIW...TFX...PIH...
   MSO...

   LAT...LON   45461363 45831325 47281053 48170871 48500648 48340484
               47970382 47410312 46750274 46110267 45980278 44830282
               43490290 43170353 43450485 44020590 44430806 44480922
               44691188 44781300 45311376 45461363 

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.
spc.feedback@noaa.gov
Page last modified: May 18, 2014
Disclaimer
Information Quality
Help
Glossary
Privacy Policy
Freedom of Information Act (FOIA)
About Us
Career Opportunities