Alert archive / California / Severe Thunderstorm Warnings in 2002
Severe Thunderstorm Warning 1, NWS Hanford, CA
NWS Hanford, CA issued this severe thunderstorm warning at May 20, 2002, 2:18 PM PDT for Fresno County, Madera County, California. It was in force for 42 min. 3 reports came from inside the area while it was in force.
The area
The counties it named, with what was reported inside it.
The facts
- Issued
- May 20, 2002, 2:18 PM PDT (21:18 UTC)
- Expired
- May 20, 2002, 3:00 PM PDT
- In force
- 42 min
- Issued by
- NWS Hanford, CA
- Area
- Counties, with a storm outline in the text
Counties Fresno County, CA, Madera County, CA
The radar
The San Joaquin Valley radar (KHNX), 75 km from the middle of the area, began a volume at 21:20 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.
What was reported inside it
| Time | Report | Where | Remark |
|---|---|---|---|
| May 20, 2:25 PM PDT | Thunderstorm Wind 50 E | Chowchilla, CA | Several hundred trees were downed in an orchard east of Chowchilla due to strong wind accompanying approximately 1" of rain with the event. |
| May 20, 2:40 PM PDT | Hail 1 | (Fat) Air Terminal, CA | |
| May 20, 3:00 PM PDT | Hail 1 | Clovis, CA |
NCEI Storm Data entries that began inside the alert's area while it was in force. Before 2003 the local storm report archive is thin, so this is the record of what happened rather than what was phoned in.
The nearest sounding before it
Oakland, CA (KOAK), launched 12:00Z, 9.3 hours before the alert went out and 235 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
- 4 J/kg
- Mixed-layer CIN
- -206 J/kg
- Mixed-layer LCL
- 592 m above ground
- 0-6 km bulk shear
- 37 kt
- 0-1 km storm-relative helicity
- -46 m²/s²
- 0-3 km storm-relative helicity
- -31 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
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, 2:00 PM PDT, 18 minutes earlier.
Area forecast discussion, May 20, 2:00 PM PDT, 18 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 office that day
Everything else NWS Hanford, CA issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| 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 |
| May 20, 4:31 PM PDT | Severe Thunderstorm Warning | HNX | Fresno | 29 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; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.