Alert archive / California / Severe Thunderstorm Warnings in 2001
Severe Thunderstorm Warning 4, NWS Hanford, CA
NWS Hanford, CA issued this severe thunderstorm warning at Apr 7, 2001, 4:56 PM PDT for Merced County, California. It was in force for 29 min. 1 report came from inside the area while it was in force.
The area
The outline the Iowa Environmental Mesonet reconstructed for it; the warning itself named whole counties, with what was reported inside it.
The facts
- Issued
- Apr 7, 2001, 4:56 PM PDT (23:56 UTC)
- Expired
- Apr 7, 2001, 5:25 PM PDT
- In force
- 29 min
- Issued by
- NWS Hanford, CA
- Area
- Whole counties; the outline is the Mesonet’s reconstruction
County Merced County, CA
The radar
The San Joaquin Valley radar (KHNX), 124 km from the middle of the area, began a volume at 23:55 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 |
|---|---|---|---|
| Apr 7, 5:21 PM PDT | Hail 0.75 | Merced, 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, 11.9 hours before the alert went out and 165 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
- 8 J/kg
- Mixed-layer CIN
- -24 J/kg
- Mixed-layer LCL
- 627 m above ground
- 0-6 km bulk shear
- 32 kt
- 0-1 km storm-relative helicity
- 15 m²/s²
- 0-3 km storm-relative helicity
- 12 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 072356 SVRFAT CAC039-047-080030- BULLETIN - EAS ACTIVATION REQUESTED SEVERE THUNDERSTORM WARNING NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY CA 456 PM PDT SAT APR 7 2001 THE NATIONAL WEATHER SERVICE IN HANFORD CA HAS ISSUED A * SEVERE THUNDERSTORM WARNING FOR... EAST MERCED COUNTY IN CENTRAL CALIFORNIA * UNTIL 525 PM PDT * AT 456 PM PDT...DOPPLER RADAR SHOWED A SEVERE THUNDERSTORM 5 MILES SOUTH OF MERCED...MOVING SOUTHEAST AT 7 MPH. * THE SEVERE THUNDERSTORM WILL REMAIN OVER... RURAL EASTERN MERCED COUNTY THROUGH 525 PM PDT SEVERE THUNDERSTORMS CAN PRODUCE TORNADOES WITH LITTLE OR NO ADVANCE WARNING. PREPARE TO MOVE TO A PLACE OF SAFETY IN A STURDY STRUCTURE SUCH AS A BASEMENT OR SMALL INTERIOR ROOM IF A TORNADO IS SPOTTED. HAIL UP TO 1 INCH IN DIAMETER IS POSSIBLE WITH THIS STORM. IF YOU ARE IN THE PATH OF THE STORM...PUT YOUR CAR IN A GARAGE AND MOVE TO A SUBSTANTIAL SHELTER. 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 3734 12048 3720 12063 3702 12040 3719 12022 BENTZIEN
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 Apr 7, 3:20 PM PDT, 1 hour 36 minutes earlier.
Area forecast discussion, Apr 7, 3:20 PM PDT, 1 hour 36 minutes before
INTERIOR CENTRAL CALIFORNIA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY - HANFORD CA
320 PM PDT SAT APR 7 2001
A VORTICITY CENTER MOVING THROUGH THE STRONG COLD POOL ALOFT /IN
WAKE OF THIS MORNING/S COLD FRONT/ HAS TRIGGERED WIDESPREAD
SHALLOW CONVECTION ACROSS THE CENTRAL AND SOUTHERN SAN JOAQUIN
VALLEY AND THE FOOTHILLS...AND EVEN SOME THUNDERSNOW OVER THE KERN
COUNTY DESERTS. SEVERAL REPORTS OF FUNNEL CLOUDS AND PEA-SIZE HAIL.
CONVECTION WILL CONTINUE INTO THE EVENING...THEN BEGIN TO DIE OFF
AFTER SUNSET.
SNOW SHOWERS IN THE MOUNTAINS WILL TAPER OFF OVERNIGHT. PER
COORDINATION WITH WFO/S SACRAMENTO AND RENO WILL ALLOW SNOW ADVISORY
FOR THE FOOTHILLS TO EXPIRE...AND DOWNGRADE THE WINTER STORM WARNING
FOR THE SOUTHERN SIERRA NEVADA ABOVE 4000 FEET TO A SNOW ADVISORY
UNTIL 06Z. WILL ALSO LET THE WINTER WEATHER ADVISORY FOR THE KERN
COUNTY MOUNTAINS EXPIRE...BUT ISSUE A WIND ADVISORY UNTIL 06Z. IN
THE KERN COUNTY DESERTS...SOME GUSTS TO 40-50 MPH CONTINUE...SO WIND
ADVISORY THERE ON TRACK.
SOME INSTABILITITY SHOWERS WILL REDEVELOP OVER THE REGION SUNDAY...
BUT DO NOT EXPECT REDEVELOPMENT OF CONVECTION. THE 12Z MODELS DROP
ANOTHER VORTICITY CENTER...ABOUT +30...AROUND THE BASE OF THE TROUGH
AND INTO THE SOUTHLAND MONDAY AFTERNOON. THIS WILL ENHANCE THE
INSTABILITY OVER THE REGION...SO WILL GO WITH A CHANCE OF SHOWERS
OVER THE SAN JOAQUIN VALLEY AND KERN DESERTS...WITH SHOWERSA LIKELY
OVER THE MOUNTAINS.
FOR THE EXTENDED FORECAST PERIOD...ANOTHER SHORT-WAVE DROPS INTO THE
TROUGH MONDAY NIGHT AND ACROSS SOUTHERN CALIFORNIA TUESDAY MORNING.
WILL KEEP MENTION OF TUESDAY MORNING SHOWERS IN THE EXTENDED
FORECAST...THEN DECREASING CLOUDS AND BECOMING PARTLY CLOUDY AND
CONTINUED UNSEASONABLY COOL FOR THE REMAINDER OF THE EXTENDED
FORECAST PERIOD.
POPS FAT 5204 BFL 4204 YNP 7536. SANGER
.HNX...SNOW ADVISORY UNTIL 1100 PM FOR THE SOUTHERN SIERRA NEVADA
ABOVE 4000 FEET FROM YOSEMITE NATIONAL PARK TO THE KERN
COUNTY LINE.
...WIND ADVISORY UNTIL 1100 PM FOR THE KERN COUNTY MOUNTAINS.
...WIND ADVISORY UNTIL 1100 PM FOR THE KERN COUNTY DESERTS.
aNearby
Severe Thunderstorm Warnings in California, 2001Every severe thunderstorm warning in 2001
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.