Alert archive / California / Severe Thunderstorm Warnings in 2002
Severe Thunderstorm Warning 4, NWS Hanford, CA
NWS Hanford, CA issued this severe thunderstorm warning at May 20, 2002, 4:31 PM PDT for Fresno County, California. It was in force for 29 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
- May 20, 2002, 4:31 PM PDT (23:31 UTC)
- Expired
- May 20, 2002, 5:00 PM PDT
- In force
- 29 min
- Issued by
- NWS Hanford, CA
- Area
- Counties, with a storm outline in the text
County Fresno County, CA
The radar
The San Joaquin Valley radar (KHNX), 61 km from the middle of the area, began a volume at 23:35 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
Vandenberg AFB, CA (KVBG), launched 12:00Z, 11.5 hours before the alert went out and 254 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.
- Mixed-layer CAPE
- 94 J/kg
- Mixed-layer CIN
- -2 J/kg
- Mixed-layer LCL
- 494 m above ground
- 0-6 km bulk shear
- 90 kt
- 0-1 km storm-relative helicity
- -17 m²/s²
- 0-3 km storm-relative helicity
- 87 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
000 WUUS56 KHNX 202331 SVRFAT CAC019-210015- BULLETIN - EAS ACTIVATION REQUESTED SEVERE THUNDERSTORM WARNING NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY CA 430 PM PDT MON MAY 20 2002 THE NATIONAL WEATHER SERVICE IN HANFORD CA HAS ISSUED A * SEVERE THUNDERSTORM WARNING FOR... CENTRAL FRESNO COUNTY IN CENTRAL CALIFORNIA * UNTIL 500 PM PDT * AT 420 PM PDT...DOPPLER RADAR SHOWED A SEVERE THUNDERSTORM OVER CENTRAL FRESNO COUNTY...OR ABOUT 14 MILES EAST OF CLOVIS...MOVING EAST AT 35 MPH. * THE SEVERE THUNDERSTORM WILL BE NEAR PINE FLAT RESERVOIR THROUGH 515 PM PDT REPORT SEVERE WEATHER TO THE NEAREST LAW ENFORCEMENT AGENCY. THEY WILL RELAY YOUR REPORT TO THE NATIONAL WEATHER SERVICE FORECAST OFFICE IN HANFORD CA. LAT...LON 3686 11950 3668 11946 3674 11916 3694 11917
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 Hanford, CA wrote its last area forecast discussion before this severe thunderstorm warning went out at May 20, 3:05 PM PDT, 1 hour 26 minutes earlier.
Area forecast discussion, May 20, 3:05 PM PDT, 1 hour 26 minutes before
INTERIOR CENTRAL CALIFORNIA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY - HANFORD CA
305 PM PDT MON MAY 20 2002
WATER VAPOR IMAGES SHOW A LARGE CUTOFF UPPER LEVEL LOW CENTER OFF
THE NORTH CALIFORNIA COAST. COLDER MORE UNSTABLE AIR OVER
NORTHWESTERN CA. A FEW SHOWERS AND THUNDERSTORMS AFFECTED THE
CENTRAL SAN JOAQUIN VALLEY AND YOSEMITE OVERNIGHT. THE THREAT OF
SHOWERS AND THUNDERSTORMS WILL BE HIGH TODAY AS THE UPPER LOW MOVES
EAST ACROSS CALIFORNIA. THE COLDER AIR ALOFT WILL FURTHER
DESTABILIZE THE ATMOSPHERE AND THE SAN JOAQUIN VALLEY WILL BE UNDER
THE FAVORABLE LEFT FRONT QUAD OF A STRONG 130 KNOT JET. HODOGRAPH
SHOWS STRONG STRAIGHT LINE SHEAR FAVORABLE FOR RIGHT SPLITTING
CELLS. LOW WETBULB ZERO TEMPERATURE INDICATES STORMS MAY BE
ACCOMPANIED WITH SMALL HAIL. SOUTHWEST MID LEVEL WIND AT 40-50 MPH
WILL PROVIDE FAVORABLE OROGRAPHIC LIFT OVER THE SIERRA. WILL POST A
WINTER STORM WARNING FOR THE SIERRA NORTH OF KINGS CANYON FOR
POSSIBLE SNOW ACCUMULATIONS OF 6-12 INCHES...AND A WINTER WEATHER
ADVISORY FOR THE TULARE COUNTY MOUNTAINS FOR SNOW ACCUMULATIONS OF
3-8 INCHES. ALSO WILL HOIST A WIND ADVISORY FOR KERN COUNTY
MOUNTAINS AND DESERTS FOR THIS AFTERNOON AND EVENING WITH UPPER JET
MOVING OVER THE TEHACHAPI MNTS AND MODELS PROG LOCAL PRESSURE
GRADIENTS TO INCREASE 10-12MB. BEST DYNAMICS WILL BE ACROSS THE
CENTRAL SAN JOAQUIN VALLEY AND SIERRA AND WILL CARRY
LIKELY-CATEGORICAL POPS AND CHANCE IN THE SOUTHERN SAN JOAQUIN AND
KERN COUNTY MOUNTAINS. WIND FLOW TURNS NORTHWEST AS THROUGH AXIS
MOVES THROUGH AROUND 06Z MONDAY NIGHT. EXPECT LOTS OF LOW LEVEL
CLOUDINESS TUESDAY MORNING WITH SOME LINGERING SHOWERS ALONG THE
MOUNTAINS WITH NW LOW LEVEL FLOW MAY BANKING MOISTURE ALONG
FOOTHILLS AND SOUTH SIDE OF THE VALLEY. 500MB HEIGHTS RISE BY 50M
AND TEMPERATURES SHOULD RECOVER WEDNESDAY. A HIGH PRESSURE RIDGE
BUILDS OVER THE AREA FOR THE EXTENDED PERIOD AND WARM DRY WEATHER
SHOULD RETURN CA.
.HNX...WINTER STORM WATCH MONDAY AND MONDAY NIGHT FOR THE SOUTHERN
SIERRA FROM YOSEMITE TO KINGS CANYON.
...WIND ADVISORY FOR KERN COUNTY MOUNTAINS AND
DESERTS THIS AFTERNOON THROUGH 9:00 PM...
MVThe office that day
Everything else NWS Hanford, CA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 20, 2:18 PM PDT | Severe Thunderstorm Warning | HNX | Fresno, Madera | 42 min |
| May 20, 3:02 PM PDT | Severe Thunderstorm Warning | HNX | Fresno | 43 min |
| May 20, 3:36 PM PDT | Severe Thunderstorm Warning | HNX | Fresno | 44 min |
| May 20, 4:01 PM PDT | Tornado Warning | HNX | Madera, Mariposa, Merced | 44 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.