Alert archive / Idaho / Tornado Warnings in 1990

Tornado Warning 1, NWS Boise, ID

April 20, 1990Jerome County, Twin Falls County, Idaho

NWS Boise, ID issued this tornado warning at Apr 20, 1990, 2:30 PM MDT for Jerome County, Twin Falls County, Idaho. It was in force for 45 min. 1 report 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
Apr 20, 1990, 2:30 PM MDT (20:30 UTC)
Expired
Apr 20, 1990, 3:15 PM MDT
In force
45 min
Issued by
NWS Boise, ID
Area
Whole counties

Counties Jerome County, ID, Twin Falls County, ID

The radar

The WSR-88D network and its archive begin in 1991, so there is no radar volume for this alert.

What was reported inside it

TimeReportWhereRemark
Apr 20, 3:24 PM MDTTornado F0Twin Falls, ID

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. Storm Data before 1996 records only tornadoes, thunderstorm wind and hail.

The nearest sounding before it

Boise Airport, ID (KBOI), launched 12:00Z, 8.5 hours before the alert went out and 183 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, Boise Airport, ID at 12:00Z on 1990-04-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Boise Airport, ID at 12:00Z on 1990-04-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -87 square meters per square second.193958Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1339 m above ground
0-6 km bulk shear
21 kt
0-1 km storm-relative helicity
-87 m²/s²
0-3 km storm-relative helicity
148 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 
TTAA00 KBOI 202044 COR
TORBOI
IDC053-083-202115-

BULLETIN - EBS ACTIVATION REQUESTED
TORNADO WARNING...CORRECTION
NATIONAL WEATHER SERVICE BOISE ID
230 PM MDT FRI APR 20 1990

...CORRECTION TO LOCATION OF TORNADO SIGHTING...

THE NATIONAL WEATHER SERVICE IN BOISE IDAHO HAS ISSUED A
TORNADO WARNING EFFECTIVE UNTIL  315 PM MDT
FOR PEOPLE IN THE FOLLOWING COUNTIES...

IN SOUTH CENTRAL IDAHO
          ...JEROME...NORTHERN TWIN FALLS

A TORNADO WAS SIGHTED EAST OF KIMBERLY IDAHO AT 2:24 PM MDT. THE
TORNADO DISSIPITATED A FEW MINUTES LATER. AN ADDITIONAL FUNNEL CLOUD
WAS SIGHTED NEAR I84 MILEPOST 190 NEAR VALLEY ROAD IN JEROME COUNTY.
<
IF YOU ARE IN THE PATH OF A TORNADO...THE SAFEST PLACE IS A
BASEMENT.  GET UNDER A WORKBENCH OR PIECE OF STURDY FURNITURE.
IF NO BASEMENT IS AVAILABLE...SEEK SHELTER IN AN INTERIOR ROOM
SUCH AS A CLOSET ON THE LOWEST FLOOR.  USE BLANKETS...PILLOWS...
OR CUSHIONS TO COVER YOUR BODY.  AVOID WINDOWS.

END...WSFO BOISE

The office that day

Everything else NWS Boise, ID issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 20, 4:45 PM MDTSevere Thunderstorm WarningBOIAda, Canyon, Owyhee60 min

Nearby

Tornado Warnings in Idaho, 1990Every tornado warning in 1990Tornadoes in 1990

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.