Alert archive / Colorado / Severe Thunderstorm Warnings in 1987
Severe Thunderstorm Warning 56, NWS Denver/Boulder, CO
NWS Denver/Boulder, CO issued this severe thunderstorm warning at Jul 8, 1987, 6:59 PM MDT for Weld County, Colorado. It was in force for 61 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
- 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
County Weld 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 8, 7:18 PM MDT | Hail 1.5 | Weld, 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 00:00Z, 1.0 hours before the alert went out and 125 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.
- 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
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.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 8, 6:59 PM MDT | Severe Thunderstorm Warning | BOU | Adams, Arapahoe | 61 min |
| Jul 9, 4:08 PM MDT | Severe Thunderstorm Warning | BOU | Sedgwick | 42 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; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive.