Alert archive / California / Mesoscale Discussions in 2006

Mesoscale Discussion 607

April 21, 200618 counties in California

The Storm Prediction Center issued this mesoscale discussion at Apr 21, 2006, 1:57 PM PDT for 18 counties in California. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Apr 21, 2006, 1:57 PM PDT (20:57 UTC)
Expired: Apr 21, 2006, 4:00 PM PDT
In force: 2 hr
Issued by: the Storm Prediction Center

Counties Amador County, CA, Butte County, CA, Calaveras County, CA, Colusa County, CA, Contra Costa County, CA, Fresno County, CA, Glenn County, CA, Madera County, CA, Merced County, CA, Napa County, CA, Sacramento County, CA, San Joaquin County, CA, Solano County, CA, Stanislaus County, CA, Sutter County, CA, Tehama County, CA, Yolo County, CA, Yuba County, CA

The radar

The Sacramento radar (KDAX), 29 km from the middle of the area, began a volume at 21:01 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

Oakland, CA (KOAK), launched 12:00Z, 9.0 hours before the alert went out and 121 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: 986 m above ground
0-6 km bulk shear: 35 kt
0-1 km storm-relative helicity: -7 m²/s²
0-3 km storm-relative helicity: 41 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 212058
SWOMCD
SPC MCD 212057 
CAZ000-212300-

MESOSCALE DISCUSSION 0607
NWS STORM PREDICTION CENTER NORMAN OK
0357 PM CDT FRI APR 21 2006

AREAS AFFECTED...NORTHERN/CENTRAL CA

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 212057Z - 212300Z

THREAT FOR ISOLATED HAIL WILL INCREASE REMAINDER OF THE AFTERNOON
ACROSS INTERIOR PORTIONS OF NORTHERN/CENTRAL CA. A WATCH IS NOT
CURRENTLY ANTICIPATED...HOWEVER WILL CONTINUE TO MONITOR CONVECTIVE
TRENDS.

WATER VAPOR IMAGERY FEATURES UPPER LOW JUST OFF THE CENTRAL CA
COAST. AS THIS LOW NEARS THE COAST...MID LEVEL LAPSE RATES WILL
CONTINUE TO STEEPEN INTO INTERIOR CA. INITIAL THUNDERSTORM
DEVELOPMENT IS ALREADY NOTED EAST OF THE BAY AREA...WITH INCREASING
CONVECTIVE COVERAGE EXPECTED THROUGH LATE AFTERNOON FROM THE COASTAL
AREAS INTO THE SACRAMENTO/SAN JOAQUIN VALLEYS. PROGRESSIVELY COOL
TEMPERATURES ALOFT COUPLED WITH A MILD BOUNDARY LAYER AND UPPER
40S/LOWER 50S DEWPOINTS WILL LEAD TO POTENTIAL FOR MOST UNSTABLE
CAPES IN EXCESS OF 1000 J/KG PER ADJUSTED RUC SOUNDINGS...ESPECIALLY
IN AREAS FROM SACRAMENTO/STOCKTON AND SOUTH. PRIMARY SEVERE HAZARD
IS LIKELY TO BE HAIL THROUGH EARLY EVENING...ALTHOUGH A FEW FUNNELS
MAY BE POSSIBLE AS WELL.

..GUYER.. 04/21/2006

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

ATTN...WFO...HNX...STO...MTR...

40482263 40562202 40142158 39442099 38172048 36791933
36461966 36372013 36902089 37822193 38772268 39342278

Nearby

Mesoscale Discussions in California, 2006 Every mesoscale discussion in 2006

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.