Alert archive / Colorado / Severe Thunderstorm Warnings in 1990

Severe Thunderstorm Warning 30, NWS Denver/Boulder, CO

July 9, 1990Denver County, Jefferson County, Colorado

NWS Denver/Boulder, CO issued this severe thunderstorm warning at Jul 9, 1990, 7:58 PM MDT for Denver County, Jefferson County, Colorado. It was in force for 32 min.

The area

The counties it named.

The facts

Issued: Jul 9, 1990, 7:58 PM MDT (01:58 UTC)
Expired: Jul 9, 1990, 8:30 PM MDT
In force: 32 min
Issued by: NWS Denver/Boulder, CO
Area: Whole counties

Counties Denver County, CO, Jefferson County, CO

The radar

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

The nearest sounding before it

Denver, CO (KDEN), launched 00:00Z, 2.0 hours before the alert went out and 158 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 2289 J/kg
Mixed-layer CIN: -19 J/kg
Mixed-layer LCL: 1419 m above ground
0-6 km bulk shear: 49 kt
0-1 km storm-relative helicity: 29 m²/s²
0-3 km storm-relative helicity: 54 m²/s²
Significant tornado parameter: 0.2
Supercell composite: 1.8

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

000 
TTAA00 KDEN 100159
SVRDEN
COC059-031-001-123-100240-

BULLETIN...IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE DENVER CO
758 PM MDT MON JUL 09 1990

THE NATIONAL WEATHER SERVICE HAS ISSUED A SEVERE THUNDERSTORM
WARNING EFFECTIVE UNTIL 840 PM  MDT FOR PEOPLE IN THE
FOLLOWING COUNTIES OF NORTHEAST COLORADO:

     NORTHEASTERN JEFFERSON
     EXTREME NORTHERN DENVER
     WESTERN ADAMS
     SOUTHERN WELD

INCLUDING THE FOLLOWING TOWNS/CITIES:

     ARVADA..COMMERCE CITY..GOLDEN..LAKEWOOD..MOUNTAIN VIEW..
     NORTHGLENN..PLEASANT VIEW..THORNTON..WESTMINSTER..
     AND WHEAT RIDGE

AT 750 PM MDT...SEVERE THUNDERSTORMS WITH LARGE HAIL...STRONG WINDS
AND HEAVY RAIN WERE LOCATED FROM WESTERN ADAMS COUNTY TO NORTHEAST 
JEFFERSON COUNTY AND EXTENDED INTO EXTREME SOUTHERN WELD COUNTY.

THE STRONGEST ACTIVITY WAS INDICATED OVER WESTMINISTER...WHERE 3/4
INCH HAIL WAS REPORTED...AND FROM BRIGHTON TO 20 MILES EAST OF
BRIGHTON.  MOVEMENT WAS TOWARDS THE EAST ABOUT 15 MPH.

FUNNEL CLOUDS WERE REPORTED ABOUT 745 PM IN EXTREME SOUTHWEST WELD
COUNTY AND NORTHWEST ADAMS COUNTY.

IF SEVERE WEATHER APPROACHES YOUR AREA..GO TO A STURDY
SHELTER AWAY FROM CREEK BEDS AND OTHER FLOOD PRONE AREAS.
REMEMBER..A SEVERE THUNDERSTORM CAN PRODUCE LARGE DAMAGING
HAIL..DAMAGING WINDS OF OVER 60 MPH..DEADLY LIGHTNING..AND
HEAVY RAINS THAT CAN QUICKLY FLOOD A LOW LYING AREA.

DULONG

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.

In the hours before

Special weather statement, Jul 9, 6:47 PM MDT, 1 hour 11 minutes before

COZ011-012-100130-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
640 PM MDT MON JUL 9 1990

...RAPIDLY DEVELOPING THUNDERSTORMS IN DENVER AREA...

AT 640 PM MDT...RADAR INDICATED RAPID-GROWING THUNDERSTORMS IN THE
EASTERN DENVER METRO-AREA.  THESE WERE LOCATED BETWEEN WATKINS AND
BARR LAKE...AND IN THE GREENWOOD VILLAGE-SOUTHEAST AURORA AREA.

THESE STORMS SHOULD MOVE EASTWARD AT A MODERATE PACE...BUT COULD
PRODUCE BRIEF HEAVY DOW4NPOURS DURING THE NEXT 30 TO 45 MINUTES.

ANOTHER CLUSTER OF THUNDERSTORMS WILL MOVE ACROSS THE SOUTHERN
METRO-AREA...AFFECTING THE AREAS OF HIGHLANDS RANCH...ENGLEWOOD...
AND SOUTH DENVER IN THE NEXT HOUR.

DULONG

The office that day

Everything else NWS Denver/Boulder, CO issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 9, 6:57 PM MDT	Tornado Warning	BOU	Adams, Arapahoe, Denver	45 min
Jul 9, 7:58 PM MDT	Severe Thunderstorm Warning	BOU	Adams, Weld	42 min
Jul 9, 9:10 PM MDT	Tornado Warning	BOU	Washington	43 min
Jul 9, 9:10 PM MDT	Tornado Warning	BOU	Morgan, Weld	43 min
Jul 9, 10:00 PM MDT	Tornado Warning	BOU	Logan, Morgan, Washington	45 min
Jul 9, 10:52 PM MDT	Severe Thunderstorm Warning	BOU	Washington	38 min

Nearby

Severe Thunderstorm Warnings in Colorado, 1990 Every severe thunderstorm warning 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; the sounding from the Mesonet's radiosonde archive.