Mesoscale Discussion 1329

Issued

Jun 30, 2012, 7:33 PM PDT (02:33 UTC)

Expired

Jun 30, 2012, 10:00 PM PDT

In force

2 hr

Issued by

the Storm Prediction Center

Chance of a watch

5%

The Spokane radar (KOTX), 64 km from the middle of the area, began a volume at 02:36 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.

871 
ACUS11 KWNS 010234
SWOMCD
SPC MCD 010233
MTZ000-IDZ000-ORZ000-WAZ000-010500-

MESOSCALE DISCUSSION 1329
NWS STORM PREDICTION CENTER NORMAN OK
0933 PM CDT SAT JUN 30 2012

AREAS AFFECTED...ERN WA...NERN ORE...NRN ID...NWRN MT

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 010233Z - 010500Z

PROBABILITY OF WATCH ISSUANCE...5 PERCENT

SUMMARY...A VERY ISOLATED SVR THREAT WILL EXIST INTO THE OVERNIGHT
HOURS...AND A WW IS NOT NEEDED.

DISCUSSION...WITHIN THE OVERLAPPING ZONE OF THE NWRN PERIPHERY OF A
GREAT BASIN ELEVATED MIXED LAYER AND THE ERN FRINGES OF A
TROPOSPHERIC MOIST PLUME LEADING AN APPROACHING PACIFIC SHORTWAVE
TROUGH...MUCAPE VALUES IN EXCESS OF 1000 J/KG COVER PARTS OF THE
INTERIOR NORTHWEST. MARGINAL MIXED-LAYER BUOYANCY IS BEING
MAINTAINED BY SFC DEWPOINTS IN THE 50S AMIDST MODEST LOW-LEVEL LAPSE
RATES...THOUGH GROWING INHIBITION OWING TO NOCTURNAL COOLING WILL
RESULT IN INCREASING INHIBITION DURING THE NEXT SEVERAL HOURS.
REGARDLESS...SUFFICIENT DEEP FORCING FOR ASCENT ATTENDANT TO THE
AFOREMENTIONED SHORTWAVE TROUGH WILL BE SUFFICIENT FOR ISOLATED
STORMS TO CONTINUE INTO THE OVERNIGHT HOURS AS WEAK MID-LEVEL HEIGHT
FALLS OVERSPREAD THE AREA.

AN INTENSE STORM OVER NRN WALLOWA COUNTY HAS RECENTLY EXPERIENCED
RIGHTWARD DEVIANT MOTION RELATIVE TO SSWLY FLOW OF 20-40 KT FROM 2-7
KFT AGL PER PENDLETON VWP DATA...WHILE DEVELOPING A REAR INFLOW
NOTCH. A SVR THREAT WILL LIKELY ACCOMPANY THIS STORM AS IT TRACKS
INTO PARTS OF ASOTIN/NEZ PERCE/LEWIS COUNTIES DURING THE NEXT HOUR.
ALSO...7-KM CAPPI DATA INDICATE AN UPTICK IN CONVECTION FARTHER NW
INTO ERN WA.

GIVEN 30-50 KT OF EFFECTIVE BULK SHEAR JUXTAPOSED WITH THE
AFOREMENTIONED BUOYANCY...A VERY ISOLATED SVR THREAT WILL EXIST
TONIGHT. STORMS MAY APPROACH NWRN MT AFTER 04Z AS THE SHORTWAVE
TROUGH MAKES ADDITIONAL PROGRESS INLAND. HOWEVER...IN THE ABSENCE OF
GREATER BUOYANCY/STRONGER FORCING FOR ASCENT...THE SVR THREAT IS
FORECAST TO REMAIN VERY ISOLATED.

..COHEN/HART.. 07/01/2012

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

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

LAT...LON   48791410 47201365 45641532 44781817 45011997 46292075
            48031985 48871843 49041631 48791410

Mesoscale Discussions in Washington, 2012Mesoscale Discussions in Idaho, 2012Mesoscale Discussions in Montana, 2012Every mesoscale discussion in 2012

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.