Mesoscale Discussion 855

Issued

Jun 9, 2016, 6:05 PM MDT (00:05 UTC)

Expired

Jun 9, 2016, 7:30 PM MDT

In force

85 min

Issued by

the Storm Prediction Center

The Glasgow radar (KGGW), 129 km from the middle of the area, began a volume at 00:09 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

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• Severe Thunderstorm Watch 240Jun 9, 6:45 PM MDT

235 
ACUS11 KWNS 100006
SWOMCD
SPC MCD 100005 
NDZ000-SDZ000-MTZ000-100130-

MESOSCALE DISCUSSION 0855
NWS STORM PREDICTION CENTER NORMAN OK
0705 PM CDT THU JUN 09 2016

AREAS AFFECTED...CNTRL/ERN MT...WRN ND

CONCERNING...SEVERE THUNDERSTORM WATCH 239...

VALID 100005Z - 100130Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 239
CONTINUES.

SUMMARY...THE SEVERE THREAT SHOULD DIMINISH FROM WEST TO EAST ACROSS
THE REMAINING PART OF WW 239 THROUGH THE EVENING. CONVECTIVE TRENDS
WILL BE MONITORED FOR POSSIBLE DOWNSTREAM WW ISSUANCE INTO WESTERN
NORTH DAKOTA.

DISCUSSION...AT 00Z...A LONG-LIVED INTENSE SUPERCELL WAS MOVING
QUICKLY EWD INTO PRAIRIE AND MCCONE COUNTIES IN MONTANA.
STRONG/POTENTIALLY SEVERE TSTMS ARE ALSO ONGOING TO THE SOUTHWEST
AND NORTH OF THAT CELL. THE SURFACE PATTERN IS BECOMING INCREASINGLY
COMPLEX ACROSS THE AREA...WITH A WEAK COLD FRONT DRAPED ACROSS CNTRL
MT/NWRN ND...OUTFLOW SURGING NWD OUT OF CONVECTION IN N-CNTRL
WY...AND A WEAK SFC TROUGH IN PLACE ACROSS FAR ERN MT INTO WRN ND.
STRONG SWLY MIDLEVEL FLOW WILL CONTINUE TO SUPPORT SUFFICIENT
DEEP-LAYER SHEAR FOR ORGANIZED CONVECTIVE STRUCTURES WHERE
SURFACE-BASED BUOYANCY CAN BE MAINTAINED. NEW INITIATION IS POSSIBLE
ON THE VARIOUS BOUNDARIES FOR THE NEXT 1-2 HRS...SUCH AS THE RECENT
DEVELOPMENT IN YELLOWSTONE COUNTY MT. 

SUPERCELLS WILL CONTINUE TO BE POSSIBLE FOR THE NEXT 1-2 HRS WITH AN
ATTENDANT LARGE HAIL AND ISOLATED DAMAGING WIND RISK. THE LEAD
SUPERCELL WILL ALSO POSE SOME RISK OF A TORNADO AS IT MOVES INTO A
REGION WITH SOMEWHAT RICHER LOW-LEVEL MOISTURE ON THE COOL SIDE OF
THE FRONT. WHILE ONLY A MODEST INCREASE IN THE LOW-LEVEL JET IS
FORECAST THIS EVENING...SOME UPSCALE GROWTH IS POSSIBLE AS COLD
POOLS CONGLOMERATE...WITH AN ATTENDANT DAMAGING WIND RISK.  

SOME INCREASE IN CONVECTION HAS BEEN NOTED RECENTLY ACROSS SWRN ND
INTO NWRN SD...WHILE ONGOING CONVECTION IN MONTANA/WYOMING MAY BEGIN
TO SPREAD INTO WRN ND/NWRN SD BY 01-02Z. DOWNSTREAM WATCH ISSUANCE
INTO THESE AREAS IS POSSIBLE IF CONVECTIVE TRENDS INDICATE A THREAT
OF MULTIPLE SEVERE STORMS LASTING INTO THE EVENING.

..DEAN/CORFIDI.. 06/10/2016

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...BIS...UNR...BYZ...GGW...TFX...

LAT...LON   45571150 46511147 47880877 48850704 49010590 49000288
            48760175 48330163 47450178 46460205 44930272 45060658
            45571150

Mesoscale Discussions in Montana, 2016Mesoscale Discussions in North Dakota, 2016Mesoscale Discussions in South Dakota, 2016Every mesoscale discussion in 2016

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.