Alert archive / Oregon / Mesoscale Discussions in 2007

Mesoscale Discussion 992

June 3, 200711 counties in Oregon; 9 counties in Washington

The Storm Prediction Center issued this mesoscale discussion at Jun 3, 2007, 4:22 PM PDT for 11 counties in Oregon; 9 counties in Washington. It was in force for 113 min.

The area

The outline as issued.

The facts

Issued: Jun 3, 2007, 4:22 PM PDT (23:22 UTC)
Expired: Jun 3, 2007, 6:15 PM PDT
In force: 113 min
Issued by: the Storm Prediction Center

Counties Deschutes County, OR, Gilliam County, OR, Hood River County, OR, Jefferson County, OR, Morrow County, OR, Sherman County, OR, Umatilla County, OR, Union County, OR, Wallowa County, OR, Wasco County, OR, Wheeler County, OR, Asotin County, WA, Benton County, WA, Chelan County, WA, Columbia County, WA, Garfield County, WA, Kittitas County, WA, Klickitat County, WA, Walla Walla County, WA, Yakima County, WA

The radar

The Pendleton radar (KPDT), 118 km from the middle of the area, began a volume at 23:26 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

Salem/Mcnary, OR (KSLE), launched 12:00Z, 11.4 hours before the alert went out and 249 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: 1246 m above ground
0-6 km bulk shear: 23 kt
0-1 km storm-relative helicity: -2 m²/s²
0-3 km storm-relative helicity: 65 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.

000 
ACUS11 KWNS 032322
SWOMCD
SPC MCD 032322 
ORZ000-WAZ000-040115-

MESOSCALE DISCUSSION 0992
NWS STORM PREDICTION CENTER NORMAN OK
0622 PM CDT SUN JUN 03 2007

AREAS AFFECTED...ORE...WA

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 032322Z - 040115Z

STRONG HEATING AND RELATIVELY HIGH MOISTURE CONTENT HAVE CONTRIBUTED
TO MODERATE INSTABILITY ACROSS THE CASCADE MOUNTAINS THIS AFTERNOON.
SCATTERED SEVERE STORMS ARE POSSIBLE OVER THE NEXT FEW HOURS BUT
OVERALL COVERAGE/DURATION OF THE THREAT DOES NOT APPEAR SUFFICIENT
FOR A WATCH AT THIS TIME.

OROGRAPHIC UPLIFT ACROSS THE CASCADES AND THE BLUE MOUNTAINS HAS
RESULTED DEEP CONVECTIVE INITIATION OVER THE PAST COUPLE OF HOURS.
ACTIVITY WILL CONTINUE TO TAP INTO STRONGLY UNSTABLE AIR MASS ACROSS
THE REGION WITH STOUT UPDRAFTS APPARENT ON SATELLITE AND RADAR
IMAGERY ACROSS YAKIMA COUNTY IN WA...AND JEFFERSON AND WALLOWA
COUNTIES IN ORE. VERY HOT WELL-MIXED BOUNDARY LAYER IN THE LOWER
ELEVATIONS WAS CONTRIBUTING TO DCAPE VALUES WELL IN EXCESS OF 1000
J/KG. THUS ANY ACTIVITY DRIFTING NWD/NEWD OFF THE HIGHER TERRAIN
WILL POSE A RISK OF POTENTIALLY DAMAGING DOWNBURST WINDS.

ENTIRE REGION LIES TO THE EAST OF STRONGER MID LEVEL SLY FLOW
ASSOCIATED WITH AN APPROACHING LARGE SCALE PACIFIC TROUGH. WHILE
ASCENT AHEAD OF THIS SYSTEM MAY AID ADDITIONAL STORM DEVELOPMENT
OVER THE NEXT FEW HOURS...WEAK DEEP-LAYER SLY FLOW ACROSS THE AREA
WAS RESULTING IN ONLY LIMITED EFFECTIVE SHEAR AND THIS IS EXPECTED
TO INHIBIT GREATER STORM ORGANIZATION/PERSISTENCE. HOWEVER...GIVEN
MAGNITUDE OF AVAILABLE INSTABILITY...COUPLED WITH TERRAIN AND STORM
SCALE ENHANCEMENTS...A FEW SEVERE HAIL/WIND EVENTS APPEAR POSSIBLE
OVER THE NEXT FEW HOURS.

..CARBIN.. 06/03/2007

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

ATTN...WFO...BOI...OTX...PDT...MFR...SEW...PQR...

45651699 45251733 44421982 44342081 43222174 43662215
44872193 45542191 47102172 47532178 48182169 48472173
48952093 47332044 46362018 46231946 46711731

Nearby

Mesoscale Discussions in Oregon, 2007 Mesoscale Discussions in Washington, 2007 Every mesoscale discussion in 2007

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.