Alert archive / California / Severe Thunderstorm Warnings in 2002

Severe Thunderstorm Warning 2, NWS Sacramento, CA

March 7, 2002Calaveras County, Stanislaus County, California

NWS Sacramento, CA issued this severe thunderstorm warning at Mar 7, 2002, 1:45 PM PST for Calaveras County, Stanislaus County, California. It was in force for 45 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Mar 7, 2002, 1:45 PM PST (21:45 UTC)
Expired
Mar 7, 2002, 2:30 PM PST
In force
45 min
Issued by
NWS Sacramento, CA
Area
Counties, with a storm outline in the text

Counties Calaveras County, CA, Stanislaus County, CA

The radar

The Sacramento radar (KDAX), 92 km from the middle of the area, began a volume at 21:49 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.

Did it verify

Not verified. The Iowa Environmental Mesonet's Cow found no qualifying storm report inside this severe thunderstorm warning while it was in force. That is not proof nothing happened: reports are thin where few people live.

Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.

The nearest sounding before it

Oakland, CA (KOAK), launched 12:00Z, 9.8 hours before the alert went out and 132 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-pSkew-T log-p diagram, Oakland, CA at 12:00Z on 2002-03-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 72 joules per kilogram.LCLEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Oakland, CA at 12:00Z on 2002-03-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 43 square meters per square second.1939587897Sfc1 km3 km6 km9 kmRMLM
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
72 J/kg
Mixed-layer CIN
-2 J/kg
Mixed-layer LCL
684 m above ground
0-6 km bulk shear
33 kt
0-1 km storm-relative helicity
43 m²/s²
0-3 km storm-relative helicity
111 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 
WUUS56 KSTO 072151
SVRSAC
CAC009-099-072230-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING...CORRECTED
NATIONAL WEATHER SERVICE SACRAMENTO CA
144 PM PST THU MAR 7 2002

THE NATIONAL WEATHER SERVICE HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  WESTERN CALAVERAS COUNTY IN CALIFORNIA
  NORTHEASTERN STANISLAUS COUNTY IN CALIFORNIA

* VALID UNTIL 230 PM PST

* AT 131 PM PST...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM 6 MILES SOUTHWEST OF MILTON...MOVING NORTHEAST
  AT 30 MPH.

* SOME LOCATIONS AFFECTED BY THIS WARNING INCLUDE...
  HODSON
  MILTON
  MURPHYS

IF YOU ARE CAUGHT OUTSIDE...SEEK SHELTER FROM THE WEATHER IN A STRONG
BUILDING. DAMAGING WIND...LARGE HAIL...VERY HEAVY RAIN...AND DEADLY
LIGHTNING ARE ALL POSSIBLE IN SEVERE THUNDERSTORMS. STAY INSIDE AWAY
FROM WINDOWS UNTIL THE STORM HAS PASSED.

REPORT SIGNIFICANT WEATHER TO THE NEAREST LAW ENFORCEMENT AGENCY.
THEY WILL RELAY YOUR REPORT TO THE NATIONAL WEATHER SERVICE FORECAST
OFFICE.

LAT...LON 3802 12098 3789 12082 3817 12042 3833 12062

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Sacramento, CA wrote its last area forecast discussion before this severe thunderstorm warning went out at Mar 7, 8:45 AM PST, 5 hours earlier.

Area forecast discussion, Mar 7, 8:45 AM PST, 5 hours before
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
845 AM PST THU MAR 7 2002

MODERATE SNOW IS BEING REPORTED AT BLUE CANYON WITH OTHER REPORTING
STATIONS INDICATING LIGHT RAIN...ALTHOUGH RADAR INDICATES SOME
EMBEDDED PATCHES OF MODERATE PRECIPITATION...MAINLY IN THE FOOTHILLS
AND COASTAL HILLS SOUTH OF THE BAY AREA. EXPECT CONTINUED DEVELOPMENT
THIS MORNING...TAPERING OFF AND BECOMING CONVECTIVE THIS AFTERNOON.
RADAR IS ONLY INDICATING LIMITED RETURNS IN THE COLD AIR OFFSHORE
ALTHOUGH THE CLOUD FIELD IN IR SAT PIX SUGGEST ENOUGH MOISTURE TO
TRIGGER SHOWERS AFTER FRONTAL PASSAGE. THUNDERSTORMS A POSSIBILITY
AGAIN TODAY AS THE AIRMASS BECOMES LESS STABLE. GRIDDED MODEL DATA
DELAYED DUE TO COMMUNICATION PROBLEMS AT GATEWAY. PLAN TO UPDATE
ZONES LATER THIS MORNING AS PRECIPITATION DIMINISHES. NO CHANGE TO
WARNINGS OR ADVISORIES AT THIS TIME. SOUTHERLY SURFACE WINDS HAVE
INCREASED THIS MORNING BUT STILL BELOW ADVISORY CRITERIA.

.STO...WINTER STORM WARNING FOR THE WEST SLOPE OF THE NORTHERN SIERRA
       NEVADA TODAY...
       WINTER STORM WARNING FOR WESTERN PLUMAS COUNTY TODAY THROUGH
       THURSDAY MORNING.
       SNOW ADVISORY TODAY FOR THE SHASTA COUNTY MOUNTAINS AND
       PORTIONS OF THE COASTAL RANGE.

The office that day

Everything else NWS Sacramento, CA issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Mar 6, 4:16 PM PSTSevere Thunderstorm WarningSTOTehama29 min
Mar 7, 1:51 PM PSTSevere Thunderstorm WarningSTOCalaveras, Stanislaus39 min
Mar 7, 2:36 PM PSTSevere Thunderstorm WarningSTOCalaveras, Stanislaus, Tuolumne39 min

Nearby

Severe Thunderstorm Warnings in California, 2002Every severe thunderstorm warning in 2002

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.