Tornado and Hail in California, May 20, 2002

Name: Tornado and Hail in California, May 20, 2002
Start: 2002-05-20T13:13
End: 2002-05-20T15:24
Location: California

May 20, 2002 · NWS HNX · 5 events in 1 county or zone

The thunderstorm that supported a tornado at approximately 1500 PST also brought very large hail and locally heavy rain to areas to the north and north-northeast of Madera and the tornado track area.

Where it happened

Every event with a place to put it; 1 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.

Tornadoes
Tropical storms and surge
Floods
Wind
Hail
Winter weather
Heat and drought
Cold
Fire, smoke and dust
Marine and coastal
Other

Open the live radar over this ground

The toll

Deaths: 0
Injuries: 0
Property damage: $130,000
Crop damage: $256,000
Events: 5

Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.

What happened

The episode as NWS HNX wrote it up.

The thunderstorm that supported a tornado at approximately 1500 PST also brought very large hail and locally heavy rain to areas to the north and north-northeast of Madera and the tornado track area.

What forecasters said that day

The local office's own words before the first event, 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 the first event at May 20, 1:00 PM PST, 13 minutes earlier.

Area forecast discussion, May 20, 1:00 PM PST, 13 minutes before

INTERIOR CENTRAL CALIFORNIA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HANFORD CA
200 PM PDT MON MAY 20 2002

WATER VAPOR LOOPS SHOW COLD CORE LOW MOVING INTO NORCAL EARLY THIS
AFTERNOON. ONE VORT LOPE FROM THIS LOW MOVED OVER CENTRAL CA EARLIER
THIS MORNING AND IS MOVING EAST OF THE SIERRA CREST. SECOND VORT
LOBE IS MOVING ONTO THE CENTRAL COAST NOW...AND WILL PASS THRU THE
AREA LATER THIS AFTERNOON. A THIRD VORT LOBE SEEN OUT AT 125W...AND
THIS WILL MOVE THRU THIS EVE. THESE WILL KEEP SHOWERS AND T-STORMS
PERSISTENT THRU THIS EVE...BEFORE UPPER TROF AXIS SWINGS THRU...AND
DRYING BEGINS FROM THE NW OVERNITE. WINDS IN THE KERN MTNS AND
DESERTS HAVE BEEN SLOW TO PICK UP...BUT STILL THINK THIS WILL OCCUR
LATER THIS AFTERNOON...AND WILL LEAVE WAD UP FOR NOW. ON TUES...MTNS
REMAIN IN A SLIGHT CYCLONIC FLOW...AND WITH LINGERING MOISTURE...
WILL CONT WITH SOME LOW CHANCE POPS THOSE AREAS. VALLEY ZONES MAY
SEE SOME SUN FROM TIME TO TIME...BUT FOR THE MOST PART...MOIST COOL
AIRMASS WILL ALLOW DEVELOPMENT OF A LOT OF SC...BUT SHOULD NOT SEE
ANY PRECIP. HEIGHTS WILL GRADUALLY RISE TUE AND WED...AND TEMPS
SHOULD MODERATE ABOUT 10 DEGREES WED...UNDER MOSUNNY SKIES. FOR
THURS...THE AVN DROPS AN INSIDE SLIDER TYPE SYS INTO THE GREAT BASIN
AND STABILIZES HEIGHTS TEMPORARILY...BUT STILL SHOULD SEE ANOTHER
COUPLE OF DEGS WARMING. AFTER THURS...FLAT RIDGE BUILDS ACROSS THE
REGION...AND TEMPS WILL RISE TO A LITTLE ABOVE NORMAL FOR THE
HOLIDAY WEEKEND.  FAT 7-00 BFL 6-00 YNP +300     BINGHAM

.HNX...WINTER STORM WARNING TONIGHT FROM YOSEMITE TO KINGS CANYON.
    ...WINTER WEATHER ADVISORY TONIGHT FOR THE TULARE COUNTY
       MOUNTAINS.
    ...WIND ADVISORY THIS EVENING FOR THE KERN MOUNTAINS AND
       DESERTS.

The radar

The San Joaquin Valley radar (KHNX), 101 km away, was scanning. The volume nearest the first event began at 21:25 UTC.

Open the radar archive at this moment

Event by event

2 hail, 1 funnel cloud, 1 thunderstorm wind, 1 tornado. Local standard time, as filed.

Funnel Cloud, Madera

When: May 20, 1:13 PM PST to 1:18 PM PST
Where: Madera County, 5 mi WSW of Chowchilla
Reported by: LAW ENFORCEMENT
Coordinates: 37.218, -119.763 (the zone’s center; the record gives no point)

Thunderstorm Wind, Madera

When: May 20, 1:25 PM PST to 1:30 PM PST
Where: Madera County, 7 mi ESE of Chowchilla
Measured: 50 kt (58 mph)
Reported by: GOVT OFFICIAL
Coordinates: 37.083, -120.150

Several hundred trees were downed in an orchard east of Chowchilla due to strong wind accompanying approximately 1" of rain with the event.

Tornado, Madera

When: May 20, 2:59 PM PST to 3:20 PM PST
Where: Madera County, 4 mi S of Madera Muni Arpt
Rating: F1
Path length: 2.7 mi
Path width: 40 yd
Property damage: $130,000
Reported by: NWS STORM SURVEY
Coordinates: 36.933, -120.117

This tornado occurred from the explosive development of a cell along neighboring cells' outflow boundary convergence. The tornado track on the ground was 2.675 miles and mostly F0 in intensity and as wide as 100 yards. It began relatively weak, peeling roofs off from farm structures, downing trees and fencing, but engulfing a well-built structure with minimal damage. However, a 1/4-mile stretch reached F1 intensity as it totally demolished a small farm structure toward the end of its run and was narrowed to a 40-yard path width at that point. The tornado occurred essentially in a rural area of south Madera, tracked west-to-east, but finished with a sweep toward the southeast.

Hail, Madera

When: May 20, 3:15 PM PST to 3:18 PM PST
Where: Madera County, 3 mi NE of Madera Muni Arpt
Measured: 1.75 in hail
Crop damage: $256,000
Reported by: GENERAL PUBLIC
Coordinates: 37.017, -120.083

Much like Fresno and Tulare Counties to the south, various sizes of hail scarred vegetables and fruit within localized rural areas of Madera County. Nonetheless, the largest hail fell generally within a semi-rural area north of the city of Madera.

Hail, Madera

When: May 20, 3:20 PM PST to 3:24 PM PST
Where: Madera County, 6 mi NE of Madera Muni Arpt
Measured: 1.5 in hail
Reported by: GENERAL PUBLIC
Coordinates: 37.050, -120.033

Total rainfall from this event was 2.35" in the area around Madera Golf and Country Club.

What these are

Funnel Cloud: A rotating column of cloud extending from a thunderstorm that did not reach the ground.
Thunderstorm Wind: Winds from a thunderstorm of 50 knots (58 mph) or more, or lower winds that caused damage or casualties. Measured gusts are marked MG, estimated EG.
Tornado: A violently rotating column of air in contact with the ground and extending from a thunderstorm, filed with its path, width and Fujita or Enhanced Fujita rating from the damage survey.
Hail: Hail three-quarters of an inch or larger, or smaller hail that caused damage, filed with the largest stone measured.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

Every storm in California in 2002 Every state in 2002 This day in weather history The tornado archive for California, 2002 Warnings in California, May 2002

Sources

NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 5290951, 5290952, 5290868, 5290949, 5290950.