Alert archive / Wyoming / Mesoscale Discussions in 2016

Mesoscale Discussion 673

May 21, 2016Carter County, Powder River County, Montana; 5 counties in Wyoming

The Storm Prediction Center issued this mesoscale discussion at May 21, 2016, 8:16 PM MDT for Carter County, Powder River County, Montana; 5 counties in Wyoming. It was in force for 89 min.

The area

The outline as issued.

The facts

Issued: May 21, 2016, 8:16 PM MDT (02:16 UTC)
Expired: May 21, 2016, 9:45 PM MDT
In force: 89 min
Issued by: the Storm Prediction Center

Counties Carter County, MT, Powder River County, MT, Campbell County, WY, Converse County, WY, Crook County, WY, Niobrara County, WY, Weston County, WY

The radar

The Rapid City radar (KUDX), 190 km from the middle of the area, began a volume at 02:16 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Rapid City, SD (KRAP), launched 00:00Z, 2.3 hours before the alert went out and 187 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 868 m above ground
0-6 km bulk shear: 24 kt
0-1 km storm-relative helicity: 88 m²/s²
0-3 km storm-relative helicity: 154 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

003 
ACUS11 KWNS 220216
SWOMCD
SPC MCD 220216 
MTZ000-WYZ000-220345-

MESOSCALE DISCUSSION 0673
NWS STORM PREDICTION CENTER NORMAN OK
0916 PM CDT SAT MAY 21 2016

AREAS AFFECTED...ERN WY...SERN MT

CONCERNING...SEVERE THUNDERSTORM WATCH 189...

VALID 220216Z - 220345Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 189
CONTINUES.

SUMMARY...ISOLATED HAIL THREAT AND STRONG WIND THREAT SHOULD
GRADUALLY DECREASE THROUGH LATE EVENING ACROSS ERN WY AND SERN MT.

DISCUSSION...A BROKEN LINE OF TSTMS PERSISTS FROM ERN MT SWD INTO
E-CNTRL WY...WITH MORE RECENT TSTM DEVELOPMENT FOCUSED S OF WW 189
NEAR/N OF THE LARAMIE MTNS OF WY. RADAR TRENDS SUGGEST THESE STORMS
REMAIN CAPABLE OF PRODUCING ISOLATED SVR HAIL. LOW-LEVEL MOISTURE
AXIS REMAINS CENTERED ACROSS ERN WY...BUT WILL GRADUALLY SHIFT EWD
IN CONJUNCTION WITH AN INCREASING NOCTURNAL LLJ OVER WRN NEB AND THE
WRN DAKOTAS. THIS...ALONG WITH CONTINUED BOUNDARY-LAYER COOLING...IS
EXPECTED TO RESULT IN A GRADUAL DECREASE IN BOTH HAIL/WIND POTENTIAL
THROUGH WATCH EXPIRATION TIME OF 06Z...BUT ISOLATED INSTANCES OF SVR
HAIL AND STRONG WIND GUSTS STILL REMAIN POSSIBLE...PARTICULARLY WITH
SUSTAINED DISCRETE STORMS ACROSS SRN PORTIONS OF WW 189 INTO E-CNTRL
WY.

..ROGERS.. 05/22/2016

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

ATTN...WFO...UNR...CYS...BYZ...RIW...

LAT...LON   46280426 43870415 42440425 42080511 42100552 42450586
            43620574 44630629 45660608 46190576 46310506 46280426

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 21, 6:38 PM MDT	Mesoscale Discussion	SPC	Carter, Custer, Daniels, Dawson, Fallon, Garfield and 10 more	67 min

Nearby

Mesoscale Discussions in Wyoming, 2016 Mesoscale Discussions in Montana, 2016 Every mesoscale discussion in 2016

Sources

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.