Alert archive / Oregon / Mesoscale Discussions in 2012

Mesoscale Discussion 1439

July 8, 201214 counties in Oregon; 7 counties in Washington

The Storm Prediction Center issued this mesoscale discussion at Jul 8, 2012, 3:21 PM PDT for 14 counties in Oregon; 7 counties in Washington. It was in force for 54 min.

The area

The outline as issued.

The facts

Issued: Jul 8, 2012, 3:21 PM PDT (22:21 UTC)
Expired: Jul 8, 2012, 4:15 PM PDT
In force: 54 min
Issued by: the Storm Prediction Center
Chance of a watch: 20%

All 21 counties

Baker County, OR, Crook County, OR, Deschutes County, OR, Gilliam County, OR, Grant 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, Benton County, WA, Columbia County, WA, Franklin County, WA, Garfield County, WA, Klickitat County, WA, Walla Walla County, WA, Yakima County, WA

The radar

The Pendleton radar (KPDT), 53 km from the middle of the area, began a volume at 22:23 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

Boise Airport, ID (KBOI), launched 12:00Z, 10.4 hours before the alert went out and 291 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: 2827 m above ground
0-6 km bulk shear: 29 kt
0-1 km storm-relative helicity: -18 m²/s²
0-3 km storm-relative helicity: 112 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.

160 
ACUS11 KWNS 082221
SWOMCD
SPC MCD 082221 
ORZ000-WAZ000-082315-

MESOSCALE DISCUSSION 1439
NWS STORM PREDICTION CENTER NORMAN OK
0521 PM CDT SUN JUL 08 2012

AREAS AFFECTED...N-CNTRL/NERN ORE...S-CNTRL/SERN WA

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 082221Z - 082315Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...ISOLATED DMGG WIND/HAIL THREAT MAY DEVELOP THIS AFTERNOON
AND EVENING FROM CNTRL/E-CNTRL ORE NWD INTO S-CNTRL AND SERN WA.
COVERAGE/MAGNITUDE OF THE THREAT APPEARS TO BE TOO MARGINAL TO
WARRANT A WW...BUT CONVECTIVE TRENDS WILL BE MONITORED.

DISCUSSION...VISIBLE SATELLITE LOOP SHOWS INCREASING COVERAGE OF
TOWERING CU AND CB FIELD OVER PARTS OF CNTRL/NERN ORE. THIS APPEARS
TO BE OCCURRING IN RESPONSE TO A WEAK UPPER WAVE TRANSLATING NWD OUT
OF NRN CA...AS STRONG HEATING HAS ALLOWED CONVECTIVE TEMPERATURES TO
BE REACHED. A TREND FOR INCREASING COVERAGE OF CONVECTION IS
EXPECTED TO CONTINUE THROUGH THE NEXT 2-3 HRS...WITH MODERATELY
STRONG MIDLEVEL FLOW /E.G. 30-40 KTS/ ALONG THE ERN PERIPHERY OF A
LARGE-SCALE PACIFIC TROUGH SUPPORTIVE FOR STORM ORGANIZATION. THE
POTENTIAL FOR ISOLATED DMGG WIND GUSTS/LARGE HAIL APPEARS TO BE
MAXIMIZED OVER WRN PORTIONS OF THE HIGHLIGHTED RISK AREA...INCLUDING
AREAS ALONG AND IN THE IMMEDIATE LEE OF THE ERN SLOPES OF THE
CASCADE MTN RANGE. HERE...SLIGHTLY STRONGER MIDLEVEL FLOW/EFFECTIVE
SHEAR WILL BE MORE FAVORABLE FOR ORGANIZED CLUSTERS PROPAGATING NWD
THIS AFTERNOON/EVENING. THE PRIMARY LIMITING FACTOR FOR A MORE
WIDESPREAD SVR THREAT WILL BE MARGINAL MLCAPE VALUES RANGING BETWEEN
500-1000 J/KG /PER RAP OBJECTIVE ANALYSIS/...WHICH WILL LIKELY
PRECLUDE WW ISSUANCE...BUT CONVECTIVE TRENDS WILL CONTINUE TO BE
MONITORED.

..ROGERS/CORFIDI.. 07/08/2012

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

ATTN...WFO...BOI...OTX...PDT...PQR...

LAT...LON   45721700 44971720 44091738 43531807 43611929 43732168
            44092185 45882167 46482118 46791922 46821837 46571757
            45721700

Nearby

Mesoscale Discussions in Oregon, 2012 Mesoscale Discussions in Washington, 2012 Every mesoscale discussion in 2012

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.