Alert archive / Idaho / Mesoscale Discussions in 2010

Mesoscale Discussion 1521

July 31, 20104 states

The Storm Prediction Center issued this mesoscale discussion at Jul 31, 2010, 4:13 PM PDT for 4 states. It was in force for 92 min.

The area

The outline as issued.

The facts

Issued: Jul 31, 2010, 4:13 PM PDT (23:13 UTC)
Expired: Jul 31, 2010, 5:45 PM PDT
In force: 92 min
Issued by: the Storm Prediction Center

Counties Benewah County, ID, Clearwater County, ID, Idaho County, ID, Latah County, ID, Lewis County, ID, Nez Perce County, ID, Shoshone County, ID, Mineral County, MT, Baker County, OR, Union County, OR, Wallowa County, OR, Asotin County, WA, Garfield County, WA

The radar

The Pendleton radar (KPDT), 151 km from the middle of the area, began a volume at 23:17 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

Spokane, WA (KOTX), launched 12:00Z, 11.2 hours before the alert went out and 231 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: 69 J/kg
Mixed-layer CIN: -264 J/kg
Mixed-layer LCL: 2380 m above ground
0-6 km bulk shear: 28 kt
0-1 km storm-relative helicity: -17 m²/s²
0-3 km storm-relative helicity: 34 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.

595 
ACUS11 KWNS 312313
SWOMCD
SPC MCD 312313 
IDZ000-MTZ000-ORZ000-WAZ000-010045-

MESOSCALE DISCUSSION 1521
NWS STORM PREDICTION CENTER NORMAN OK
0613 PM CDT SAT JUL 31 2010

AREAS AFFECTED...NERN OREGON/SERN WA/PARTS OF NRN ID

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

VALID 312313Z - 010045Z

AN INCREASE IN CONVECTION IS NOTED ACROSS NERN OREGON AND INTO PART
OF NRN ID.  WHILE CONVECTION REMAINS ISOLATED ATTM...WE WILL
CONTINUE TO MONITOR THIS AREA FOR SIGNS OF INCREASING DEVELOPMENT
WHICH COULD WARRANT WW ISSUANCE.

MODEST INSTABILITY /500 TO 1000 J/KG MIXED-LAYER CAPE/ IS EVIDENT
ACROSS THE DISCUSSION AREA...WHICH IS SUPPORTING ISOLATED BUT FAIRLY
VIGOROUS CONVECTION ALONG THE SERN FRINGE OF THE MAIN UPPER
CIRCULATION CENTER OVER WRN WA.  WHILE FLOW ALOFT ACROSS MOST OF WA
AND NRN OREGON REMAINS WEAK GIVEN PROXIMITY OF THE UPPER LOW...THE
WRN FRINGE OF THE STRONGER BELT OF MID-LEVEL SWLYS EXTENDS WWD INTO
ERN WA/ERN OREGON.  THUS...A SMALL ZONE OF ENHANCED SEVERE THREAT
HAS EVOLVED W OF WW 554.

ATTM...EXPECT COVERAGE OF STRONGER STORMS TO REMAIN LIMITED -- WHICH
MAY PRECLUDE THE NEED FOR A WW.  FURTHER
DEVELOPMENT...HOWEVER...COULD NECESSITATE WW ISSUANCE.

..GOSS.. 07/31/2010

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

ATTN...WFO...MSO...BOI...OTX...PDT...

LAT...LON   44751711 44621772 44721818 45041867 46641758 47551615
            47071482 45701485 44751711

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 31, 3:27 AM PDT	Mesoscale Discussion	SPC	Benewah, Kootenai, Latah	93 min
Jul 31, 11:53 AM PDT	Mesoscale Discussion	SPC	Adams, Bingham, Blaine, Boise, Bonneville, Butte and 13 more	67 min
Jul 31, 4:02 PM PDT	Mesoscale Discussion	SPC	Clark, Fremont, Madison, Teton	118 min
Jul 31, 11:01 AM PDT	Mesoscale Discussion	SPC	Carter, Custer, Dawson, Fallon, McCone, Prairie and 4 more	89 min
Jul 31, 12:19 PM PDT	Severe Thunderstorm Watch	SPC	Beaverhead, Big Horn, Blaine, Broadwater, Carbon, Cascade and 24 more	9 hr
Jul 31, 3:38 PM PDT	Mesoscale Discussion	SPC	Sheridan	97 min

Nearby

Mesoscale Discussions in Idaho, 2010 Mesoscale Discussions in Oregon, 2010 Mesoscale Discussions in Washington, 2010 Every mesoscale discussion in 2010

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.