Alert archive / Idaho / Mesoscale Discussions in 2016

Mesoscale Discussion 1749

October 2, 201615 counties in Idaho; 10 counties in Utah; 4 counties in Wyoming

The Storm Prediction Center issued this mesoscale discussion at Oct 2, 2016, 12:38 PM MDT for 15 counties in Idaho; 10 counties in Utah; 4 counties in Wyoming. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued: Oct 2, 2016, 12:38 PM MDT (18:38 UTC)
Expired: Oct 2, 2016, 3:15 PM MDT
In force: 3 hr
Issued by: the Storm Prediction Center
Chance of a watch: 20%

All 29 counties

Bannock County, ID, Bear Lake County, ID, Bingham County, ID, Bonneville County, ID, Butte County, ID, Caribou County, ID, Clark County, ID, Franklin County, ID, Fremont County, ID, Jefferson County, ID, Madison County, ID, Minidoka County, ID, Oneida County, ID, Power County, ID, Teton County, ID, Box Elder County, UT, Cache County, UT, Davis County, UT, Morgan County, UT, Rich County, UT, Salt Lake County, UT, Summit County, UT, Utah County, UT, Wasatch County, UT, Weber County, UT, Lincoln County, WY, Sublette County, WY, Teton County, WY, Uinta County, WY

The radar

The Pocatello radar (KSFX), 113 km from the middle of the area, began a volume at 18:39 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

Salt Lake City I, UT (KSLC), launched 12:00Z, 6.6 hours before the alert went out and 178 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: 83 J/kg
Mixed-layer CIN: -99 J/kg
Mixed-layer LCL: 2290 m above ground
0-6 km bulk shear: 49 kt
0-1 km storm-relative helicity: 153 m²/s²
0-3 km storm-relative helicity: 153 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

005 
ACUS11 KWNS 021839
SWOMCD
SPC MCD 021838 
WYZ000-UTZ000-MTZ000-IDZ000-022115-

MESOSCALE DISCUSSION 1749
NWS STORM PREDICTION CENTER NORMAN OK
0138 PM CDT SUN OCT 02 2016

AREAS AFFECTED...PORTIONS OF NRN UT...SERN ID...WRN WY...AND FAR SRN
MT

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 021838Z - 022115Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...ISOLATED STRONG TO SEVERE WIND GUSTS AND MARGINALLY SEVERE
HAIL WILL BE POSSIBLE THROUGH THE AFTERNOON/EVENING. WW ISSUANCE IS
UNLIKELY AT THIS TIME...BUT CONVECTIVE TRENDS WILL CONTINUE TO BE
MONITORED.

DISCUSSION...A MID TO UPPER JET EMBEDDED WITHIN AN UPPER TROUGH/LOW
LOCATED OVER THE PACIFIC NORTHWEST WILL CONTINUE TO OVERSPREAD THE
NRN/CNTRL GREAT BASIN THIS AFTERNOON AND EVENING. ASSOCIATED
LARGE-SCALE ASCENT ALONG WITH OROGRAPHIC CIRCULATIONS WILL ENCOURAGE
ISOLATED TO SCATTERED CONVECTIVE DEVELOPMENT ACROSS THE MCD AREA
AHEAD OF A SFC LOW LOCATED OVER NERN NV/NWRN UT. 40-50 KT OF SWLY
WINDS AT 500 MB SHOULD MANIFEST AT THE SFC AS STRONG TO LOCALLY
SEVERE WIND GUSTS EMBEDDED WITHIN THUNDERSTORM CORES. STEEP
MID-LEVEL /700-500 MB/ LAPSE RATES AROUND 7.5 TO 8.0 DEG C/KM WILL
ENCOURAGE EFFICIENT DOWNWARD MOMENTUM TRANSPORT IN CONVECTIVE
DOWNDRAFTS. PRIMARY LIMITING FACTOR THAT SHOULD PRECLUDE A MORE
ROBUST/WIDESPREAD SEVERE THREAT IS MARGINAL LOW-LEVEL MOISTURE
AVAILABILITY...AS EVIDENCED BY SFC DEWPOINTS GENERALLY IN THE MID
40S TO LOWER 50S. EVEN WITH STEEP LAPSE RATES...RESULTANT MLCAPE
SHOULD REMAIN AOB 1000 J/KG THROUGH PEAK DIURNAL HEATING. MARGINALLY
SEVERE HAIL MAY ALSO BE POSSIBLE IN THE STRONGEST CORES. THIS
ISOLATED SEVERE WIND/HAIL THREAT SHOULD CONTINUE THROUGH THE EARLY
EVENING HOURS...BEFORE LOW-LEVEL COOLING REDUCES THE ALREADY
MARGINAL INSTABILITY.

..GLEASON/HART.. 10/02/2016

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

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

LAT...LON   39941271 41861324 42901385 44021353 44841257 44941097
            44840972 42980945 41820963 40531061 39891167 39941271

Nearby

Mesoscale Discussions in Idaho, 2016 Mesoscale Discussions in Utah, 2016 Mesoscale Discussions in Wyoming, 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.