Alert archive / Colorado / Severe Thunderstorm Warnings in 2019

Severe Thunderstorm Warning 93, NWS Denver/Boulder, CO

June 20, 2019Adams County, Arapahoe County, Denver County, Colorado

NWS Denver/Boulder, CO issued this severe thunderstorm warning at Jun 20, 2019, 2:47 PM MDT for Adams County, Arapahoe County, Denver County, Colorado. It was in force for 43 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
Jun 20, 2019, 2:47 PM MDT (20:47 UTC)
Expired
Jun 20, 2019, 3:30 PM MDT
In force
43 min
Issued by
NWS Denver/Boulder, CO
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

Counties Adams County, CO, Arapahoe County, CO, Denver County, CO

The radar

The Denver radar (KFTG), 4 km from the middle of the area, began a volume at 20:46 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 nearest sounding before it

Denver, CO (KDNR), launched 12:00Z, 8.8 hours before the alert went out and 111 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 12:00Z on 2019-06-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 12:00Z on 2019-06-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 2 square meters per square second.19395878Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
2431 m above ground
0-6 km bulk shear
56 kt
0-1 km storm-relative helicity
2 m²/s²
0-3 km storm-relative helicity
260 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

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 Jun 20, 10:57 AM MDT, 3 hours 50 minutes earlier.

Area forecast discussion, Jun 20, 10:57 AM MDT, 3 hours 50 minutes before
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Hazardous weather outlook, Jun 20, 10:44 AM MDT, 4 hours 3 minutes before
Hazardous Weather Outlook
National Weather Service Denver/Boulder CO
1044 AM MDT Thu Jun 20 2019

COZ030>051-211645-
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-
1044 AM MDT Thu Jun 20 2019

...STRONG STORMS POSSIBLE FOR THE EASTERN PLAINS TODAY AND
TOMORROW...

This hazardous weather outlook is for northeast and north central
Colorado.

.DAY ONE...Today and Tonight

Windy conditions are expected in the mountains and foothills with
gusts to 50 mph today. Scattered showers and thunderstorms can be
expected this afternoon and evening, with a few strong to
potentially severe thunderstorms over the east plains. Best chance
will be along and east of a line from the Colorado-Wyoming-
Nebraska border down to Hugo, south of Limon. Storms in this area
will be able to produce large hail up to 1.5 inches in diameter
and damaging outflow winds to 60 mph. Elsewhere, west of the
aforementioned area, storms will be capable of producing gusty
winds to 50 mph.

Storm activity is expected to last into the late night hours as a
jet is nearby and a cold front will be approaching from the north.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday

A cold front will move over northeast Colorado Friday morning,
ushering in a cooler and unsettled weekend. The surface cold front
will combine with southwesterly flow aloft to make it possible for
some strong to possibly severe thunderstorms to develop on the
plains Friday afternoon. The area will be further south, mainly
south of Interstate 76 down toward the Palmer Divide. Large hail
and damaging winds would be the primary threats from the strong
thunderstorms. The weekend will be even cooler than Friday, with
rain showers and thunderstorms possible through the period. An
upper level low will be moving over the northern half of the state
late Friday with temperatures possibly getting cold enough for
snow to fall over the north central mountains, including Rocky
Mountain National Park late Friday night and Saturday night.

Drier and warmer conditions are expected to return Monday through
Wednesday as the upper low moves out and an upper ridge begins
building over the southern Great Plains.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed today or tonight.

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 19, 9:14 PM MDTSpecial Weather StatementBOUBoulder31 min
Jun 20, 3:16 PM MDTSpecial Weather StatementBOUArapahoe29 min
Jun 20, 3:30 PM MDTSpecial Weather StatementBOUAdams30 min
Jun 20, 3:59 PM MDTSpecial Weather StatementBOUAdams31 min
Jun 20, 4:36 PM MDTSpecial Weather StatementBOULarimer24 min
Jun 20, 4:56 PM MDTSevere Thunderstorm WarningBOUAdams, Washington49 min
Jun 20, 5:01 PM MDTSevere Thunderstorm WarningBOULarimer, Weld44 min
Jun 20, 5:13 PM MDTSevere Thunderstorm WarningBOUArapahoe, Elbert, Lincoln, Washington32 min
Jun 20, 5:36 PM MDTSevere Thunderstorm WarningBOUWeld39 min
Jun 20, 5:44 PM MDTSpecial Weather StatementBOUWashington46 min

Nearby

Severe Thunderstorm Warnings in Colorado, 2019Every severe thunderstorm warning in 2019

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; radar from the NEXRAD Level II archive.