Alert archive / Colorado / Severe Thunderstorm Warnings in 2010

Severe Thunderstorm Warning 138, NWS Denver/Boulder, CO

July 21, 2010Logan County, Colorado

NWS Denver/Boulder, CO issued this severe thunderstorm warning at Jul 21, 2010, 5:00 PM MDT for Logan County, Colorado. It was in force for 19 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Jul 21, 2010, 5:00 PM MDT (23:00 UTC)
Expired
Jul 21, 2010, 5:19 PM MDT
In force
19 min
Issued by
NWS Denver/Boulder, CO
Area
Storm-based polygon
Hail
1.25 in
Wind
50.0 mph

County Logan County, CO

The radar

The Cheyenne radar (KCYS), 150 km from the middle of the area, began a volume at 23:03 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Jul 21, 4:04 PM MDTSevere Thunderstorm WatchSPC7 hr

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.

NWS Denver/Boulder, CO wrote its last area forecast discussion before this severe thunderstorm warning went out at Jul 21, 2:30 PM MDT, 2 hours 30 minutes earlier.

Area forecast discussion, Jul 21, 2:30 PM MDT, 2 hours 30 minutes before
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Hazardous weather outlook, Jul 21, 10:51 AM MDT, 6 hours 9 minutes before
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE DENVER CO
1051 AM MDT WED JUL 21 2010

COZ030>051-221200-
JACKSON COUNTY BELOW 9000 FEET-WEST JACKSON AND WEST GRAND
COUNTIES ABOVE 9000 FEET-GRAND AND SUMMIT COUNTIES BELOW 9000
FEET-SOUTH AND EAST JACKSON/LARIMER/NORTH AND NORTHEAST GRAND/
NORTHWEST BOULDER COUNTIES ABOVE 9000 FEET-SOUTH AND SOUTHEAST
GRAND/WEST CENTRAL AND SOUTHWEST BOULDER/GILPIN/CLEAR CREEK/
SUMMIT/NORTH AND WEST PARK COUNTIES ABOVE 9000 FEET-LARIMER AND
BOULDER COUNTIES BETWEEN 6000 AND 9000 FEET-JEFFERSON AND WEST
DOUGLAS COUNTIES ABOVE 6000 FEET/GILPIN/CLEAR CREEK/NORTHEAST PARK
COUNTIES BELOW 9000 FEET-CENTRAL AND SOUTHEAST PARK COUNTY-LARIMER
COUNTY BELOW 6000 FEET/NORTHWEST WELD COUNTY-BOULDER AND JEFFERSON
COUNTIES BELOW 6000 FEET/WEST BROOMFIELD COUNTY-NORTH DOUGLAS
COUNTY BELOW 6000 FEET/DENVER/WEST ADAMS AND ARAPAHOE COUNTIES/
EAST BROOMFIELD COUNTY-ELBERT/CENTRAL AND EAST DOUGLAS COUNTIES
ABOVE 6000 FEET-NORTHEAST WELD COUNTY-CENTRAL AND SOUTH WELD
COUNTY-MORGAN COUNTY-CENTRAL AND EAST ADAMS AND ARAPAHOE COUNTIES-
NORTH AND NORTHEAST ELBERT COUNTY BELOW 6000 FEET/NORTH LINCOLN
COUNTY-SOUTHEAST ELBERT COUNTY BELOW 6000 FEET/SOUTH LINCOLN
COUNTY-LOGAN COUNTY-WASHINGTON COUNTY-SEDGWICK COUNTY-PHILLIPS
COUNTY-
1051 AM MDT WED JUL 21 2010

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHEAST AND NORTH CENTRAL
COLORADO.

.DAY ONE...TODAY AND TONIGHT

THUNDERSTORMS WILL BECOME STRONGER AND MORE NUMEROUS THIS AFTERNOON
AS DAYTIME HEATING DESTABILIZES THE AIRMASS.  ABUNDANT MOISTURE IS
IN PLACE ACROSS THE FORECAST AREA...SO THUNDERSTORMS WILL BE CAPABLE
OF PRODUCING HEAVY RAINFALL TODAY.  RAINFALL RATES UP TO 2 INCHES
PER HOUR CAN BE ANTICIPATED WITH THE STRONGER STORMS.  THIS WOULD BE
ENOUGH TO CAUSE LOCALIZED FLOODING OF STREETS AND LOW LYING AREAS...
BUT THE STORMS WILL BE MOVING FAST ENOUGH THAT THE THREAT OF
SIGNIFICANT FLASH FLOODING APPEARS LOW.

IN ADDITION TO HEAVY RAINFALL...ONE OR TWO STORMS ACROSS THE PLAINS
MAY BECOME SEVERE WITH HAIL AROUND 1 INCH IN DIAMETER AND DAMAGING
WINDS IN EXCESS OF 60 MPH THE PRIMARY THREATS.

THE STORMS ARE EXPECTED TO DECREASE FROM WEST TO EAST ACROSS THE
AREA TONIGHT.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

DRIER WEATHER AND WARMER TEMPERATURES WILL SPREAD ACROSS THE REGION
THURSDAY AND FRIDAY WITH JUST A SLIGHT CHANCE OF THUNDERSTORMS IN
THE AFTERNOON AND EVENING.  WITH THE FLOW ALOFT WEAKENING...THE
POTENTIAL FOR SLOWER MOVING THUNDERSTORMS WILL EXIST...MAKING
LOCALLY HEAVY RAINFALL A POSSIBILITY.

FOR THE REST OF THE PERIOD...TEMPERATURES WILL BE CLOSER TO SEASONAL
NORMALS...WITH AT LEAST A SLIGHT CHANCE OF THUNDERSTORMS EXPECTED
EACH AFTERNOON AND EVENING.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT ANTICIPATED...BUT REPORTS OF HEAVY
RAINFALL OR FLOODING WOULD BE APPRECIATED.

GIMMESTAD/COOPER

In the hours before

Local storm report, Jul 21, 1:55 PM MDT, 3 hours 5 minutes before
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The office that day

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

IssuedProductOfficeCountiesLasted
Jul 20, 7:41 PM MDTSpecial Weather StatementBOUPark34 min
Jul 21, 1:47 PM MDTFlash Flood WarningBOULarimer65 min
Jul 21, 3:15 PM MDTAreal Flood AdvisoryBOUDouglas, Elbert90 min
Jul 21, 3:32 PM MDTSevere Thunderstorm WarningBOUArapahoe, Elbert43 min
Jul 21, 4:20 PM MDTAreal Flood AdvisoryBOUArapahoe, Elbert85 min
Jul 21, 4:29 PM MDTSevere Thunderstorm WarningBOULogan, Washington46 min
Jul 21, 5:42 PM MDTAreal Flood AdvisoryBOULogan, Phillips, Sedgwick, Washington78 min

Nearby

Severe Thunderstorm Warnings in Colorado, 2010Every severe thunderstorm warning in 2010

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; radar from the NEXRAD Level II archive.