Alert archive / Colorado / Severe Thunderstorm Warnings in 1987

Severe Thunderstorm Warning 55, NWS Denver/Boulder, CO

July 8, 1987Adams County, Arapahoe County, Colorado

NWS Denver/Boulder, CO issued this severe thunderstorm warning at Jul 8, 1987, 6:59 PM MDT for Adams County, Arapahoe County, Colorado. It was in force for 61 min.

The area

The counties it named.

The facts

Issued
Jul 8, 1987, 6:59 PM MDT (00:59 UTC)
Expired
Jul 8, 1987, 8:00 PM MDT
In force
61 min
Issued by
NWS Denver/Boulder, CO
Area
Whole counties

Counties Adams County, CO, Arapahoe 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, 1.0 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-pSkew-T log-p diagram, Denver, CO at 00:00Z on 1987-07-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 695 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Denver, CO at 00:00Z on 1987-07-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 30 square meters per square second.1939Sfc1 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
695 J/kg
Mixed-layer CIN
-63 J/kg
Mixed-layer LCL
2416 m above ground
0-6 km bulk shear
11 kt
0-1 km storm-relative helicity
30 m²/s²
0-3 km storm-relative helicity
14 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

The text of this product is not in the archive. The NWS text archive before 2002 is incomplete.

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 8, 1:40 PM MDT, 5 hours 19 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
140 PM MDT WED JUL 8 1987

A STRONG THUNDERSTORM HAS DEVELOPED RAPIDLY IN SOUTHEAST DOUGLAS COUNTY
THIS AFTERNOON.  AT 135 PM THE STORM WAS LOCATED ABOUT 5 MILES TO THE
SOUTHEAST OF CASTLE ROCK...MOVING TO THE EAST AT AROUND 10 TO 15 MPH.

THE STORM SHOULD PRODUCE HEAVY RAIN...HAIL AND STRONG GUSTY WINDS AS
WELL AS LIGHTNING.  THE STORM MAY EVEN BECOME SEVERE BUT WILL LIKELY
BE OUT OF DOUGLAS COUNTY BY THE TIME IT DOES SO.

PERSONS IN SOUTHEAST DOUGLAS COUNTY SHOULD KEEP AN EYE ON THE SKY AND
BE PREPARED TO SEEK SAFE SHELTER SHOULD THREATENING WEATHER APPROACH.
E.T.
AFTERNOON AND EVENING IN NORTHEAST COLORADO.
E.T.
Special weather statement, Jul 8, 4:08 PM MDT, 2 hours 51 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
409 PM MDT WED JUL 8 1987

A STRONG THUNDERSTORM HAS DEVELOPED 5 MILES SOUTHEAST OF BYERS IN
CENTRAL ARAPAHOE COUNTY AND IS MOVING TO THE EAST AT ABOUT 10 MPH.
STRONG GUSTY WINDS...HAIL...HEAVY RAIN AND LIGHTNING CAN BE EXPECTED
WITH THIS STORM.

PERSONS IN CENTRAL AND EASTERN ARAPAHOE COUNTY...INCLUDING THE TOWNS OF
BYERS AND DEER TRAIL SHOULD BE ON THE LOOKOUT AND BE READY TO MOVE TO A
PLACE OF SAFETY SHOULD THREATENING WEATHER APPROACH.  WEATHER SPOTTERS
REPORTED HAIL ONE HALF INCH IN DIAMETER FALLING BETWEEN BYERS AND DEER
TRAIL AT 404 PM MDT.

OTHER THUNDERSTORMS CONTINUE TO DEVELOP IN MANY SECTIONS OF NORTHEAST
COLYORADO...BEING MOST NUMEROUS IN WASHINGTON COUNTY SOUTH OF AKRON.
E.T.
Special weather statement, Jul 8, 5:13 PM MDT, 1 hour 46 minutes before
SPECIAL WEATHER STATEMENT/SHORT RANGE FORECAST
NATIONAL WEATHER SERVICE DENVER CO
512 PM MDT WED JUL 8 1987

STRONG THUNDERSTORMS ARE DEVELOPING IN EASTERN CLEAR CREEK COUNTY
AND ARE MOVING TO THE EAST AT ABOUT 10 MPH.  THESE STORMS SHOULD BEGIN
AFFECTING THE DENVER METROPOLITAN AREA WITHIN THE NEXT HOUR OR TWO.
STRONG GUSTY WINDS APPEAR TO BE THE MAIN EFFECT THESE STORMS WILL HAVE
ON THE DENVER AREA ALTHOUGH RAIN AND HAIL ARE A POSSIBILITY AS THESE
STORMS MOVE OFF THE MOUNTAINS.

EARLIER THUNDERSTORMS WEST OF DENVER HAVE PRODUCED GUSTY WINDS WITH ONE
GUST OF ABOUT 25 MPH CLOCKED AT THE NATIONAL WEATHER SERVICE OFFICE NEAR
STAPLETON FIELD.

CLOUDS ARE BEGINNING TO BUILD OVER THE EASTERN SECTIONS OF THE DENVER
AREA AT THIS TIME AND SHOULD DEVELOP INTO THUNDERSTORMS WITHIN THE
NEXT HOUR OR TWO.  THESE STORMS...SHOULD THEY DEVELOP...MAY BE STRONGER
THAN THE ONES MOVING OFF THE MOUNTAINS AND ARE MORE LIKELY TO PRODUCE
HAIL AND HEAVY RAIN.

IN ADDITION...THUNDERSTORMS CONTINUE TO DEVELOP AND DISSIPATE IN
CENTRAL AND EASTERN ADAMS AND ARAPAHOE COUNTIES AS WELL AS SOUTHERN
WASHINGTON AND SOUTHWEST YUMA COUNTIES AT THIS HOUR AND SHOULD CONTINUE
TO DO SO FOR THE NEXT COUPLE OF HOURS.  HAIL AS LARGE AS ONE INCH IN
DIAMETER HAS OCCURRED IN OPEN COUNTRY NORTH OF DEER TRAIL WITHIN THE
LAST HOUR.  MORE LARGE HAIL MAY BE ANTICIPATED FROM THESE STORMS.
E.T.

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 8, 6:59 PM MDTSevere Thunderstorm WarningBOUWeld61 min
Jul 9, 4:08 PM MDTSevere Thunderstorm WarningBOUSedgwick42 min

Nearby

Severe Thunderstorm Warnings in Colorado, 1987Every 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.