Alert archive / Colorado / Tornado Warnings in 1987

Tornado Warning 12, NWS Denver/Boulder, CO

July 2, 1987Adams County, Colorado

NWS Denver/Boulder, CO issued this tornado warning at Jul 2, 1987, 3:34 PM MDT for Adams County, Colorado. It was in force for 26 min. 2 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: Jul 2, 1987, 3:34 PM MDT (21:34 UTC)
Expired: Jul 2, 1987, 4:00 PM MDT
In force: 26 min
Issued by: NWS Denver/Boulder, CO
Area: Whole counties

County Adams County, CO

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

Time	Report	Where	Remark
Jul 2, 3:35 PM MDT	Tornado F1	Adams, CO
Jul 2, 3:38 PM MDT	Hail 1.75	Adams, CO

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

Denver, CO (KDEN), launched 12:00Z, 9.6 hours before the alert went out and 95 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: 51 J/kg
Mixed-layer CIN: -313 J/kg
Mixed-layer LCL: 1747 m above ground
0-6 km bulk shear: 30 kt
0-1 km storm-relative helicity: -8 m²/s²
0-3 km storm-relative helicity: 55 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 KDEN 022134
TORDEN
COC001-022200-

BULLETIN - IMMEDIATE BROADCAST REQUESTED/EBS ACTIVATION REQUESTED 
TORNADO WARNING
NATIONAL WEATHER SERVICE DENVER CO
334 PM MDT THU JUL 2 1987

THE NATIONAL WEATHER SERVICE HAS ISSUED A TORNADO WARNING 
EFFECTIVE UNTIL 400 PM MDT FOR PEOPLE IN THE FOLLOWING COUNTY OF

NORTHEAST COLORADO...WEST CENTRAL ADAMS

THIS WARNING INCLUDES THE FOLLOWING TOWNS AND CITIES... NORTHEAST
DENVER METRO AREA.

TORNADO ON THE GROUND JUST EAST OF ROCKY MOUNTAIN ARSENAL.
  REMEMBERING TO PLACE THE STORM IN RELATION TO A LARGE CITY

IN HOMES GO TO THE BASEMENT OR INTO A CLOSET OR BATHROOM.  IN SCHOOLS
..HIGH RISES AND HOSPITALS GO TO AN INTERIOR HALLWAY ON THE LOWEST
FLOOR.  IF IN MOBILE HOMES OR VEHICLES..EVACUATE THEM AND GO TO A
SUBSTANTIAL SHELTER.  IF NO SHELTER IS AVAILABLE..LIE FLAT IN THE
NEAREST DITCH..GULLY OR LOW SPOT.

IN ALL CASES..STAY AWAY FROM WINDOWS..DOORS AND OUTSIDE WALLS.
PROTECT YOUR HEAD AND FACE.  TRY TO GET UNDER SOMETHING STURDY.

TO REPORT SEVERE WEATHER HAVE THE NEAREST LAW ENFORCEMENT AGENCY
RELAY YOUR REPORT TO THE NATIONAL WEATHER SERVICE IN DENVER..OR CALL
YOUR REPORT TO THE NATIONAL WEATHER SERVICE IN DENVER AT 361-0663.
DO NOT CALL THIS NUMBER FOR INFORMATION.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT FOR MOST OF EASTERN
COLORADO

E.T.

What forecasters said that day

The local office's own words before this tornado 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 2, 2:59 PM MDT, 35 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
300 PM MDT THU JUL 2 1987

   ...STRONG THUNDERSTORMS DEVELOPING ALONG THE FRONT RANGE...

AT 255 PM MDT RADAR INDICATED THUNDERSTORMS DEVELOPING ALONG THE FRONT
RANGE.  THE STRONGEST STORMS WERE OVER LITTLETON IN WESTERN ARAPAHOE
COUNTY.. AND ABOUT 10 MILES NORTHWEST OF BOULDER IN BOULDER COUNTY.
THE STORMS ARE MOVING TOWARD THE EAST AT 10 TO 20 MPH.

THE LITTLETON STORM HAS PRODUCED HAIL HALF AN INCH IN DIAMETER.

THESE TWO STORMS MAY PRODUCE LOCAL BRIEF HEAVY RAIN..HAIL..AND STRONG
GUSTY WINDS THIS AFTERNOON..AND OTHER THUNDERSTORMS ARE LIKELY TO
DEVELOP.

MARKKANEN

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 1, 7:13 PM MDT	Severe Thunderstorm Warning	BOU	Phillips, Sedgwick	42 min
Jul 1, 9:09 PM MDT	Severe Thunderstorm Warning	BOU	Larimer	51 min
Jul 2, 3:02 PM MDT	Severe Thunderstorm Warning	BOU	Arapahoe, Douglas	53 min
Jul 2, 4:02 PM MDT	Severe Thunderstorm Warning	BOU	Adams, Arapahoe, Weld	63 min
Jul 2, 4:46 PM MDT	Severe Thunderstorm Warning	BOU	Adams, Morgan, Washington	59 min
Jul 2, 5:45 PM MDT	Severe Thunderstorm Warning	BOU	Douglas	60 min

Nearby

Tornado Warnings in Colorado, 1987 Every tornado warning in 1987 Tornadoes 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; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive.