Alert archive / Colorado / Special Weather Statements in 2021

Special Weather Statement, NWS Denver/Boulder, CO

August 19, 2021Logan County, Colorado

NWS Denver/Boulder, CO issued this special weather statement at Aug 19, 2021, 1:23 PM MDT for Logan County, Colorado. It was in force for 22 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 19, 2021, 1:23 PM MDT (19:23 UTC)
Expired: Aug 19, 2021, 1:45 PM MDT
In force: 22 min
Issued by: NWS Denver/Boulder, CO
Hail: 0.88 in
Wind: 50

County Logan County, CO

The radar

The Goodland radar (KGLD), 165 km from the middle of the area, began a volume at 19:24 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, 7.4 hours before the alert went out and 89 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 246 J/kg
Mixed-layer CIN: -241 J/kg
Mixed-layer LCL: 927 m above ground
0-6 km bulk shear: 40 kt
0-1 km storm-relative helicity: -59 m²/s²
0-3 km storm-relative helicity: 35 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.2

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 19, 9:41 AM MDT, 3 hours 42 minutes earlier.

Area forecast discussion, Aug 19, 9:41 AM MDT, 3 hours 42 minutes before

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</head>
<body>
  <main class="wrap">
    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
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        The site you requested is temporarily down for maintenance or an unexpected outage.
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        Please try again in a few minutes.
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Hazardous weather outlook, Aug 19, 9:55 AM MDT, 3 hours 28 minutes before

Hazardous Weather Outlook
National Weather Service Denver/Boulder CO
955 AM MDT Thu Aug 19 2021

COZ030>051-201600-
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-
955 AM MDT Thu Aug 19 2021

...SEVERE STORMS POSSIBLE ACROSS NORTHEAST PLAINS...

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

.DAY ONE...Today and Tonight

Showers and thunderstorms will increase in areal coverage over
the northern mountains through early this afternoon, then followed
by several rounds of showers and storms during the afternoon.
Some of these storms will produce brief heavy rain and wind gusts
up to 60 mph. There is an increasing flash flood threat mainly across
the burn scars from late morning through late afternoon, especially
over Cameron Peak and Calwood burn scars.

Over the plains, scattered storms will develop this afternoon.
Some of the storms could be severe with wind gusts to 60 mph and
hail up to two inches in diameter. The threat of severe storms is
greatest north of a line from Denver to Akron between 3 PM and 9
PM. An isolated tornado is possible, most likely over the northeast
corner of Colorado after 4 PM. Showers and thunderstorms will
decrease overnight, but it will remain windy over the mountains
and higher east slopes of the Front Range.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday

Gusty west to northwest winds will prevail Friday behind the
exiting storm system. Over far northern Colorado and in the
foothills, wind gusts up to 40 mph are expected. A few gusts to
60 mph will be possible Friday in the wind prone areas of the
foothills.

It will be windy at times through the weekend. There is only a
slight chance for showers and thunderstorms over the mountains and
foothills Saturday, otherwise dry conditions are expected into
Monday.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed after 1 PM, especially along and
north of a line from Denver to Akron.

In the hours before

Special weather statement, Aug 19, 1:23 PM MDT, 0 minutes before

Special Weather Statement
National Weather Service Denver CO
123 PM MDT Thu Aug 19 2021

COZ048-191945-
Logan County CO-
123 PM MDT Thu Aug 19 2021

...A strong thunderstorm will impact portions of southeastern Logan
County through 145 PM MDT...

At 122 PM MDT, Doppler radar was tracking a strong thunderstorm 7
miles southwest of St Petersburg, or 18 miles southeast of Sterling,
moving north at 35 mph.

HAZARD...Wind gusts up to 50 mph and nickel size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Fleming and St Petersburg.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

A Severe Thunderstorm Watch remains in effect until 800 PM MDT for
northeastern Colorado.

&&

LAT...LON 4067 10267 4066 10267 4044 10276 4044 10303
      4071 10292
TIME...MOT...LOC 1922Z 197DEG 30KT 4047 10290

MAX HAIL SIZE...0.88 IN
MAX WIND GUST...50 MPH

RPK

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 19, 2:01 PM MDT	Special Weather Statement	BOU	Logan	29 min
Aug 19, 2:13 PM MDT	Special Weather Statement	BOU	Broomfield	17 min
Aug 19, 2:17 PM MDT	Special Weather Statement	BOU	Broomfield	28 min
Aug 19, 2:24 PM MDT	Severe Thunderstorm Warning Considerable damage threat	BOU	Boulder, Broomfield, Jefferson	36 min
Aug 19, 2:30 PM MDT	Severe Thunderstorm Warning	BOU	Douglas	30 min
Aug 19, 2:39 PM MDT	Tornado Warning	BOU	Adams, Broomfield, Jefferson	36 min
Aug 19, 2:46 PM MDT	Severe Thunderstorm Warning	BOU	Adams, Weld	29 min
Aug 19, 2:59 PM MDT	Areal Flood Advisory	BOU	Adams	61 min
Aug 19, 3:05 PM MDT	Tornado Warning	BOU	Adams, Weld	25 min
Aug 19, 3:12 PM MDT	Tornado Warning	BOU	Douglas	18 min
Aug 19, 3:14 PM MDT	Severe Thunderstorm Warning	BOU	Weld	31 min
Aug 19, 3:35 PM MDT	Severe Thunderstorm Warning	BOU	Douglas, Elbert	25 min
Aug 19, 3:42 PM MDT	Severe Thunderstorm Warning Considerable damage threat	BOU	Weld	33 min
Aug 19, 3:44 PM MDT	Severe Thunderstorm Warning	BOU	Adams, Arapahoe	31 min
Aug 19, 3:46 PM MDT	Tornado Warning	BOU	Douglas, Elbert	14 min
Aug 19, 3:49 PM MDT	Severe Thunderstorm Warning	BOU	Phillips	41 min
Aug 19, 3:51 PM MDT	Severe Thunderstorm Warning	BOU	Sedgwick	24 min
Aug 19, 3:55 PM MDT	Areal Flood Advisory	BOU	Arapahoe, Denver, Douglas	22 min
Aug 19, 3:58 PM MDT	Areal Flood Advisory	BOU	Weld	30 min
Aug 19, 4:04 PM MDT	Severe Thunderstorm Warning	BOU	Arapahoe, Elbert	41 min
Aug 19, 4:06 PM MDT	Areal Flood Advisory	BOU	Logan	54 min
Aug 19, 4:07 PM MDT	Severe Thunderstorm Warning Considerable damage threat	BOU	Morgan	32 min
Aug 19, 4:10 PM MDT	Areal Flood Advisory	BOU	Phillips	95 min
Aug 19, 4:17 PM MDT	Severe Thunderstorm Warning	BOU	Adams	43 min
Aug 19, 4:18 PM MDT	Severe Thunderstorm Warning	BOU	Elbert	42 min
Aug 19, 4:25 PM MDT	Severe Thunderstorm Warning Considerable damage threat	BOU	Phillips	35 min
Aug 19, 4:32 PM MDT	Severe Thunderstorm Warning Considerable damage threat	BOU	Arapahoe	28 min
Aug 19, 4:34 PM MDT	Tornado Warning	BOU	Phillips	26 min
Aug 19, 4:52 PM MDT	Severe Thunderstorm Warning Considerable damage threat	BOU	Arapahoe, Elbert	23 min
Aug 19, 4:57 PM MDT	Areal Flood Advisory	BOU	Logan	50 min
Aug 19, 4:57 PM MDT	Tornado Warning	BOU	Phillips	33 min
Aug 19, 5:00 PM MDT	Severe Thunderstorm Warning	BOU	Adams, Morgan	30 min
Aug 19, 5:04 PM MDT	Severe Thunderstorm Warning	BOU	Logan	25 min
Aug 19, 5:09 PM MDT	Flash Flood Warning	BOU	Phillips	3 hr
Aug 19, 5:34 PM MDT	Severe Thunderstorm Warning	BOU	Phillips	26 min

Nearby

Special Weather Statements in Colorado, 2021 Every special weather statement in 2021

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.