Alert archive / Colorado / Severe Thunderstorm Warnings in 1987

Severe Thunderstorm Warning 13, NWS Denver/Boulder, CO

June 18, 1987Boulder County, Colorado

NWS Denver/Boulder, CO issued this severe thunderstorm warning at Jun 18, 1987, 4:11 PM MDT for Boulder County, Colorado. It was in force for 59 min.

The area

The counties it named.

The facts

Issued: Jun 18, 1987, 4:11 PM MDT (22:11 UTC)
Expired: Jun 18, 1987, 5:10 PM MDT
In force: 59 min
Issued by: NWS Denver/Boulder, CO
Area: Whole counties

County Boulder 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

Fort Carson/Butt, CO (KFCS), launched 12:00Z, 10.2 hours before the alert went out and 167 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: 295 J/kg
Mixed-layer CIN: -96 J/kg
Mixed-layer LCL: 908 m above ground
0-6 km bulk shear: 23 kt
0-1 km storm-relative helicity: 19 m²/s²
0-3 km storm-relative helicity: 77 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.7

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KDEN 182216
SVRDEN
COC013-001-005-031-059-182310-
 
BULLETIN...IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE DENVER CO
411 PM MDT THU JUN 18 1987
 
THE NATIONAL WEATHER SERVICE HAS ISSUED A SEVERE THUNDERSTORM
WARNING EFFECTIVE UNTIL 510 PM  MDT FOR PEOPLE IN THE
FOLLOWING COUNTIES OF NORTHEAST COLORADO:
 
     SOUTHEAST BOULDER
     WESTERN ADAMS
     DENVER
     NORTHERN JEFFERSON
 
INCLUDING THE FOLLOWING TOWNS/CITIES:
 
     ARVADA..BOULDER..BROOMFIELD..COMMERCE CITY..ELDORADO SPGS..
     ERIE..GOLDEN..LAFAYETTE..LAKEWOOD..LOUISVILLE..NORTHGLENN..
     PLEASANT VIEW..THORNTON..WESTMINSTER..AND WHEAT RIDGE
 
THE STORM IS LOCATED 15 MILES WEST OF DENVER.
 
AT 410 PM NEAR ONE INCH SIZE HAIL WAS REPORTED NEAR
LEWISVILLE 10 MILE TO THE NORTHWEST OF DENVER.

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.
 
A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT FOR MUCH OF EASTERN
COLORADO UNTIL 10 PM THIS EVENING.

TO REPORT SEVERE WEATHER HAVE THE NEAREST LAW ENFORCEMENT
AGENCY RELAY YOUR REPORT TO THE NATIONAL WEATHER SERVICE OFFICE
IN DENVER..OR CALL YOUR REPORT TO THE NATIONAL WEATHER SERVICE
AT 361-0663.  DO NOT CALL THIS NUMBER FOR INFORMATION.
 
BALINT
 
LAT..LON  4009 10539 4007 10492 3969 10487 3970 10538

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, Jun 18, 10:45 AM MDT, 5 hours 26 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
1045 AM MDT THU JUN 18 1987

...SEVERE THUNDERSTORMS POSSIBLE ACROSS EASTERN COLORADO
   THIS AFTERNOON AND EVENING...

SEVERE THUNDERSTORMS WITH LARGE HAIL AND DAMAGING WINDS ARE POSSIBLE
ACROSS ALL OF EASTERN COLORADO THIS AFTERNOON AND EVENING.  LOW LEVEL
UPSLOPE FLOW HAS BROUGHT MOISTURE INTO THE STATE FROM THE EAST AND
PRODUCED AN UNSTABLE AIR MASS OVER THE HIGH PLAINS OF EASTERN COLORADO.
THESE CONDITIONS ARE FAVORABLE FOR THE FORMATION OF SEVERE
THUNDERSTORMS.

HEAVY RAINS ARE ALSO POSSIBLE FROM SOME OF THESE THUNDERSTORMS CAUSING
MINOR FLOODING OF SMALL STREAMS AND LOW LYING AREAS.  WHILE NO MAJOR
STREAM FLOODING IS ANTICIPATED AT THIS TIME...POTENTIAL RAINFALL AMOUNTS
OF 1 TO 2 INCHES MAY PRODUCE BRIEF FLOODING OF HIGHWAYS...STREETS...
UNDERPASSES AND FLOOD PRONE AREAS.

ALL PERSONS IN EASTERN COLORADO...INCLUDING THE GREATER DENVER
METROPOLITAN AREA...SHOULD MONITOR NOAA WEATHER RADIO OR OTHER
MASS MEDIA COMMUNICATIONS FOR THE LATEST WEATHER UPDATES.

GARD...WSFO DENVER

Special weather statement, Jun 18, 1:50 PM MDT, 2 hours 21 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
150PM MDT THU JUN 18 1987

...THUNDERSTORMS OVER THE NORTHEAST COLORADO FOOTHILLS...

THUNDERSTORMS WERE DEVELOPING OVER THE NORTHEAST COLORADO FOOTHILLS
THIS AFTERNOON. THE STONGEST THUNDERSTORM WAS LOCATED IN WESTERN BOULDER
COUNTY...40 MILE NORTHWEST OF DENVER.  THE THUNDERSTORMS WERE MOVING TO
THE NORTHEAST AT 15 MPH.

THE THUNDERSTORMS WILL CONTINUE TO DEVELOP THIS AFTERNOON MOVING OUT
OVER THE PLAINS.  A FEW OF THE THUNDERSTORMS MAY BECOME SEVERE WITH
HAIL...STRONG GUSTY WINDS...LOCALLY HEAVY RAIN AND DANGEROUS LIGHTNING.
THE HEAVY RAINS WITH THE THUNDERSTORMS THIS AFTERNOON CAN CAUSE LOCAL
FLOODING OF SMALL STREAMS AND LOW LYING AREAS...LOCAL FLOODING OF
HIGHWAYS...STREETS AND UNDERPASSES.

ALL PERSONS IN EASTERN COLORADO...INCLUDING THE GREATER DENVER
METROPOLITAN AREA...SHOULD MONITOR NOAA WEATHER RADIO OR OTHER
MASS MEDIA COMMUNICATIONS FOR THE LATEST WEATHER UPDATES.

BALINT...WSFO DENVER

Special weather statement, Jun 18, 2:56 PM MDT, 1 hour 15 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
255 PM MDT THU JUN 18 1987

...THUNDERSTORMS CONTINUE OVER THE NORTHEAST COLORADO FOOTHILLS...

THUNDERSTORMS CONTINUED OVER THE THE NORTHEAST COLORADO FOOTHILLS SOUTH
WEST OF DENVER NORTH TO THE WYOMING BORDER. THE STONGEST THUNDERSTORM
WAS LOCATED NEAR BOULDER IN BOULDER COUNTY...25 MILES NORTHWEST OF
DENVER.  THE THUNDERSTORMS WERE MOVING TO THE NORTHEAST AT 15 MPH.

THE THUNDERSTORMS WILL CONTINUE TO DEVELOP THIS AFTERNOON AND ARE
BEGINNING TO MOVE OUT OVER THE PLAINS.  A FEW OF THE THUNDERSTORMS MAY
BECOME SEVERE WITH HAIL...STRONG GUSTY WINDS...LOCALLY HEAVY RAIN AND
DANGEROUS LIGHTNING.

ALL PERSONS IN EASTERN COLORA`DO...INCLUDING THE GREATER DENVER
METROPOLITAN AREA...SHOULD MONITOR NOAA WEATHER RADIO OR OTHER
MASS MEDIA COMMUNICATIONS FOR THE LATEST WEATHER UPDATES.

BALINT...WSFO DENVER

Special weather statement, Jun 18, 3:55 PM MDT, 16 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
355 PM MDT THU JUN 18 1987

...THUNDERSTORMS CONTINUE ALONG AND NEAR THE NORTHEAST COLORADO
   FOOTHILLS...

THUNDERSTORMS CONTINUED OVER THE THE NORTHEAST COLORADO FOOTHILLS SOUTH
WEST OF DENVER NORTH TO THE WYOMING BORDER. THE STONGEST THUNDERSTORMS
WERE LOCATED NEAR BOULDER IN BOULDER COUNTY...25 MILES NORTHWEST OF
DENVER AND OVER NORTHERN JEFFERSON COUNTY 15 MILES WEST OF DENVER.
THE THUNDERSTORMS WERE MOVING TO THE NORTHEAST AT 10 MPH.

THE THUNDERSTORMS WILL CONTINUE TO DEVELOP THIS AFTERNOON.  A FEW OF THE
THUNDERSTORMS MAY BECOME SEVERE WITH HAIL...STRONG GUSTY WINDS...LOCALLY
HEAVY RAIN AND DANGEROUS LIGHTNING.

PEA SIZED HAIL WAS REPORTED NEAR BOULDER...25 MILS TO THE NORTHWEST OF
DENVER AND NEAR GOLDEN 15 MILES WEST OF DENVER. ABOUT ONE HALF INCH OF
RAIN WAS INDICATED NEAR WARD...35 MILES TO THE NORTHWEST OF DENVER.

ALL PERSONS IN EASTERN COLORADO...INCLUDING THE GREATER DENVER
METROPOLITAN AREA...SHOULD MONITOR NOAA WEATHER RADIO OR OTHER
MASS MEDIA COMMUNICATIONS FOR THE LATEST WEATHER UPDATES.

BALINT...WSFO DENVER

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 17, 6:24 PM MDT	Severe Thunderstorm Warning	BOU	Washington, Yuma	61 min
Jun 18, 4:11 PM MDT	Severe Thunderstorm Warning	BOU	Adams, Denver, Jefferson	59 min
Jun 18, 5:42 PM MDT	Severe Thunderstorm Warning	BOU	Douglas	63 min

Nearby

Severe Thunderstorm Warnings in Colorado, 1987 Every severe thunderstorm warning in 1987

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.