Alert archive / Idaho / Mesoscale Discussions in 2015

Mesoscale Discussion 855

June 1, 201514 counties in Idaho; 4 counties in Montana

The Storm Prediction Center issued this mesoscale discussion at Jun 1, 2015, 12:48 PM MDT for 14 counties in Idaho; 4 counties in Montana. It was in force for 117 min.

The area

The outline as issued.

The facts

Issued: Jun 1, 2015, 12:48 PM MDT (18:48 UTC)
Expired: Jun 1, 2015, 2:45 PM MDT
In force: 117 min
Issued by: the Storm Prediction Center
Chance of a watch: 60%

Counties Bannock County, ID, Bingham County, ID, Bonneville County, ID, Butte County, ID, Caribou County, ID, Cassia County, ID, Clark County, ID, Fremont County, ID, Jefferson County, ID, Madison County, ID, Minidoka County, ID, Oneida County, ID, Power County, ID, Teton County, ID, Beaverhead County, MT, Gallatin County, MT, Madison County, MT, Park County, MT

The radar

The Pocatello radar (KSFX), 86 km from the middle of the area, began a volume at 18:51 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

The nearest sounding before it

Boise Airport, ID (KBOI), launched 12:00Z, 6.8 hours before the alert went out and 308 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: 2267 m above ground
0-6 km bulk shear: 43 kt
0-1 km storm-relative helicity: 49 m²/s²
0-3 km storm-relative helicity: 79 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

950 
ACUS11 KWNS 011849
SWOMCD
SPC MCD 011848 
WYZ000-MTZ000-IDZ000-UTZ000-012045-

MESOSCALE DISCUSSION 0855
NWS STORM PREDICTION CENTER NORMAN OK
0148 PM CDT MON JUN 01 2015

AREAS AFFECTED...SERN IDAHO...NWRN WY AND SWRN MT

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

VALID 011848Z - 012045Z

PROBABILITY OF WATCH ISSUANCE...60 PERCENT

SUMMARY...THUNDERSTORMS ARE EXPECTED TO INCREASE IN COVERAGE AND
INTENSITY FROM SERN IDAHO INTO NWRN WY AND SWRN MT AFTER 19-20Z. THE
PRIMARY THREATS WILL BE LARGE HAIL AND DAMAGING WIND GUSTS. TRENDS
ARE BEING MONITORED FOR A WW.

DISCUSSION...MOSTLY SUNNY CONDITIONS ARE DESTABILIZING THE BOUNDARY
LAYER FROM SERN ID INTO NWRN WY AND SWRN MT THIS AFTERNOON. SFC
DEWPOINTS AROUND 50F ALONG WITH STEEP MID-LEVEL LAPSE RATES ARE
SUPPORTING 1000-1500 J/KG MLCAPE. OBSERVED SOUNDINGS AND RUC PFCS
INDICATE CONVECTIVE INHIBITION WILL WEAKEN SUFFICIENTLY TO SUPPORT
MORE ROBUST STORM DEVELOPMENT AS SFC TEMPERATURES APPROACH 80F. SOME
INCREASE IN THUNDERSTORM INTENSITY HAS BEEN RECENTLY OBSERVED NEAR
THE ID/NEV BORDER. ADDITIONAL STORMS SHOULD INCREASE ALONG AND AHEAD
OF PRE-EXISTING CONVECTIVE OUTFLOW BOUNDARY CURRENTLY EXTENDING FROM
SRN IDAHO INTO SWRN MT. WV IMAGERY SHOWS WELL DEFINED VORTICITY
MAXIMUM APPROACHING SWRN ID. FORCING FOR ASCENT ACCOMPANYING THIS
FEATURE SHOULD FURTHER SUPPORT AN INCREASE IN THUNDERSTORMS. A 40 KT
MID-LEVEL JET MOVING THROUGH BASE OF VORT MAX HAS OVERSPREAD THE
UNSTABLE WARM SECTOR...CONTRIBUTING TO 30-40 KT EFFECTIVE BULK SHEAR
WHICH WILL PROMOTE UPDRAFT ROTATION. BOTH BOWING SEGMENTS AND SOME
SUPERCELL STRUCTURES ARE POSSIBLE AS STORMS MATURE LATER THIS
AFTERNOON AND EVENING.

..DIAL/MEAD.. 06/01/2015

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

ATTN...WFO...BYZ...RIW...TFX...SLC...PIH...MSO...BOI...

LAT...LON   41961372 42681405 43531328 44401286 45231290 45871177
            45880995 44631054 42321110 41961372

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jun 1, 1:40 PM MDT	Severe Thunderstorm Watch	SPC	Bannock, Bear Lake, Bingham, Blaine, Bonneville, Butte and 12 more	5 hr
Jun 1, 2:19 PM MDT	Severe Thunderstorm Watch	SPC	Lemhi	7 hr
Jun 1, 3:39 PM MDT	Mesoscale Discussion	SPC	Bannock, Bingham, Bonneville, Butte, Caribou, Cassia and 9 more	66 min
Jun 1, 1:46 PM MDT	Mesoscale Discussion	SPC	Broadwater, Carbon, Cascade, Fergus, Gallatin, Golden Valley and 13 more	89 min
Jun 1, 2:41 PM MDT	Mesoscale Discussion	SPC	Fallon, Wibaux	2 hr
Jun 1, 4:31 PM MDT	Mesoscale Discussion	SPC	Beaverhead, Broadwater, Carbon, Cascade, Fergus, Gallatin and 13 more	59 min

Nearby

Mesoscale Discussions in Idaho, 2015 Mesoscale Discussions in Montana, 2015 Every mesoscale discussion in 2015

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.