

517 

WWUS20 KWNS 082204

SEL1

SPC WW 082204

MTZ000-SDZ000-WYZ000-090500-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 401

NWS STORM PREDICTION CENTER NORMAN OK

400 PM MDT MON JUL 8 2013



THE NWS STORM PREDICTION CENTER HAS ISSUED A



* SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

  SOUTHEAST MONTANA

  WESTERN SOUTH DAKOTA

  NORTHEAST WYOMING



* EFFECTIVE THIS MONDAY AFTERNOON AND EVENING FROM 400 PM UNTIL

  1100 PM MDT.



* PRIMARY THREATS INCLUDE...

  SEVERAL VERY LARGE HAIL EVENTS TO 4 INCHES IN DIAMETER POSSIBLE

  SEVERAL DAMAGING WIND GUSTS WITH A FEW SIGNIFICANT GUSTS TO 75

    MPH POSSIBLE

  A FEW TORNADOES POSSIBLE



THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 95

STATUTE MILES EAST AND WEST OF A LINE FROM 25 MILES NORTH OF

MILES CITY MONTANA TO 75 MILES SOUTH SOUTHEAST OF GILLETTE

WYOMING.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU1).



PRECAUTIONARY/PREPAREDNESS ACTIONS...



REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE

FAVORABLE FOR SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH

AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR

THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS

AND POSSIBLE WARNINGS. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY

DO PRODUCE TORNADOES.



&&



OTHER WATCH INFORMATION...CONTINUE...WW 398...WW 399...WW 400...



DISCUSSION...WIDESPREAD THUNDERSTORMS INCLUDING EMBEDDED SUPERCELLS

ARE ONGOING ATTM ACROSS THE NRN INTERMOUNTAIN REGION AND ADJACENT

NORTHERN HIGH PLAINS...WITH THE MOST INTENSE STORMS OVER CENTRAL AND

EASTERN MONTANA.  WITH THE AXIS OF GREATEST INSTABILITY EXTENDING

SSEWD ACROSS SOUTHEASTERN MT/NORTHEASTERN WY AND INTO PARTS OF

WESTERN SOUTH DAKOTA...EXPECT STORMS TO CONTINUE MOVING

EASTWARD/EAST-SOUTHEASTWARD ACROSS THIS AREA.  SHEAR REMAINS

SUPPORTIVE OF SEVERE/SUPERCELL STORMS...AND MAY INCREASE WITH TIME

AS A MID-LEVEL JET STREAK SHIFTS EWD ACROSS THE NORTHERN

INTERMOUNTAIN REGION.  GIVEN THE FAVORABLE SHEAR AND MODERATE

INSTABILITY...VERY LARGE HAIL AND STRONG/DAMAGING WIND GUSTS ARE

EXPECTED WITH THE MOST INTENSE STORMS OVER THE NEXT SEVERAL HOURS.



AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT

TO 4 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 65

KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 550. MEAN STORM

MOTION VECTOR 28035.





...GOSS

