Alert archive / Colorado / Special Weather Statements in 2017

Special Weather Statement, NWS Denver/Boulder, CO

August 14, 2017Washington County, Colorado

NWS Denver/Boulder, CO issued this special weather statement at Aug 14, 2017, 10:02 PM MDT for Washington County, Colorado. It was in force for 58 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Aug 14, 2017, 10:02 PM MDT (04:02 UTC)
Expired
Aug 14, 2017, 11:00 PM MDT
In force
58 min
Issued by
NWS Denver/Boulder, CO

County Washington County, CO

The radar

The Denver radar (KFTG), 110 km from the middle of the area, began a volume at 04:03 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 nearest sounding before it

Denver, CO (KDEN), launched 00:00Z, 4.0 hours before the alert went out and 40 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 2017-08-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 54 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 2017-08-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 6 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
54 J/kg
Mixed-layer CIN
-12 J/kg
Mixed-layer LCL
3288 m above ground
0-6 km bulk shear
23 kt
0-1 km storm-relative helicity
6 m²/s²
0-3 km storm-relative helicity
19 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

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What forecasters said that day

The local office's own words before this special weather statement 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 special weather statement went out at Aug 14, 9:42 PM MDT, 20 minutes earlier.

Area forecast discussion, Aug 14, 9:42 PM MDT, 20 minutes before
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Hazardous weather outlook, Aug 14, 10:15 AM MDT, 11 hours 47 minutes before
Hazardous Weather Outlook
National Weather Service Denver/Boulder CO
1015 AM MDT Mon Aug 14 2017

COZ030>051-151615-
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-
1015 AM MDT Mon Aug 14 2017

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

.DAY ONE...Today and Tonight

Scattered thunderstorms will develop by early afternoon with some
of them spreading across the urban corridor by mid to late
afternoon and across the plains by early evening. The majority of
storms will produce wind gusts to 40 mph, small hail and brief
moderate to heavy rain. A few stronger storms may occur over the
far northeast plains this evening. These storms may produce heavy
rain, winds gusts to 60 mph and nickel size hail.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday

The chance for thunderstorms will increase on Tuesday, especially
across the far northeast plains of Colorado where a few storms
during the late afternoon and early evening hours could turn
severe. Large hail and damaging winds will be the main threat from
these storms. The rest of the week will continue to see a chance
of afternoon and evening thunderstorms moving out of the foothills
and across the plains. Mid and upper level moisture is expected
to keep moving across Colorado through the end of the week, and
daytime heating will be sufficient each day to produce the
showers. Brief rain, gusty winds and small hail will be the main
threats from the showers and thunderstorms.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed today or tonight.

In the hours before

Special weather statement, Aug 14, 7:53 PM MDT, 2 hours 9 minutes before
Special Weather Statement
National Weather Service Denver CO
753 PM MDT MON AUG 14 2017

COZ044-150245-
Morgan County CO-
753 PM MDT MON AUG 14 2017

...SIGNIFICANT WEATHER ADVISORY FOR CENTRAL MORGAN COUNTY UNTIL 845
PM MDT...

At 753 PM MDT, Doppler radar was tracking a strong thunderstorm 6
miles northwest of Adena School, or 8 miles southwest of Fort Morgan,
and also over Fort Morgan, moving northeast at 10 mph.

Nickel size hail and wind gusts up to 50 mph will be possible with
these storms.

Locations impacted include...
Fort Morgan, Brush, Log Lane Village, Snyder and Adena School.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Prepare for sudden gusty winds. Secure loose objects and move to a
safe shelter inside a building or vehicle.

Torrential rainfall is also occurring with this storm, and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

&&

LAT...LON 4008 10390 4019 10398 4042 10377 4033 10357
      4015 10357
TIME...MOT...LOC 0153Z 240DEG 9KT 4017 10390

GIMMESTAD
Local storm report, Aug 14, 9:11 PM MDT, 51 minutes before
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Special weather statement, Aug 14, 10:02 PM MDT, 0 minutes before
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The office that day

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

IssuedProductOfficeCountiesLasted
Aug 14, 7:53 PM MDTSpecial Weather StatementBOUMorgan52 min
Aug 14, 8:15 PM MDTAreal Flood AdvisoryBOUMorgan3 hr
Aug 14, 8:29 PM MDTSevere Thunderstorm WarningBOULogan, Morgan, Washington61 min
Aug 14, 8:47 PM MDTFlash Flood WarningBOUMorgan3 hr
Aug 14, 9:08 PM MDTSevere Thunderstorm WarningBOUMorgan, Washington52 min
Aug 15, 4:01 PM MDTSevere Thunderstorm WarningBOUWeld44 min
Aug 15, 4:02 PM MDTSevere Thunderstorm WarningBOUArapahoe, Douglas, Elbert43 min
Aug 15, 4:08 PM MDTSevere Thunderstorm WarningBOULincoln52 min
Aug 15, 4:44 PM MDTSevere Thunderstorm WarningBOUWeld46 min
Aug 15, 4:53 PM MDTSevere Thunderstorm WarningBOULincoln37 min
Aug 15, 5:07 PM MDTSevere Thunderstorm WarningBOUElbert, Lincoln38 min
Aug 15, 5:12 PM MDTAreal Flood AdvisoryBOUDouglas3 hr
Aug 15, 5:27 PM MDTSevere Thunderstorm WarningBOUMorgan, Weld53 min
Aug 15, 5:34 PM MDTAreal Flood AdvisoryBOUWeld116 min
Aug 15, 5:44 PM MDTSevere Thunderstorm WarningBOUElbert, Lincoln46 min

Nearby

Special Weather Statements in Colorado, 2017Every special weather statement in 2017

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.