Alert archive / Utah / Special Weather Statements in 2021

Special Weather Statement, NWS Grand Junction, CO

August 2, 2021San Juan County, Utah

NWS Grand Junction, CO issued this special weather statement at Aug 2, 2021, 5:12 PM MDT for San Juan County, Utah. It was in force for 48 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 2, 2021, 5:12 PM MDT (23:12 UTC)
Expired
Aug 2, 2021, 6:00 PM MDT
In force
48 min
Issued by
NWS Grand Junction, CO

County San Juan County, UT

The radar

The Cedar City radar (KICX), 220 km from the middle of the area, began a volume at 23:12 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

Grand Junction, CO (KGJT), launched 12:00Z, 11.2 hours before the alert went out and 255 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, Grand Junction, CO at 12:00Z on 2021-08-02Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 22 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Grand Junction, CO at 12:00Z on 2021-08-02The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -12 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
22 J/kg
Mixed-layer CIN
-62 J/kg
Mixed-layer LCL
1085 m above ground
0-6 km bulk shear
10 kt
0-1 km storm-relative helicity
-12 m²/s²
0-3 km storm-relative helicity
55 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 Grand Junction, CO wrote its last area forecast discussion before this special weather statement went out at Aug 2, 4:00 PM MDT, 1 hour 12 minutes earlier.

Area forecast discussion, Aug 2, 4:00 PM MDT, 1 hour 12 minutes before
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<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Service Notice</title>
  <link rel="stylesheet" href="index.css">
</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>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
      </p>
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        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
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Hazardous weather outlook, Aug 2, 4:34 AM MDT, 12 hours 38 minutes before
Hazardous Weather Outlook
National Weather Service Grand Junction CO
434 AM MDT Mon Aug 2 2021

COZ001>014-017>023-UTZ022>025-027>029-031200-
Lower Yampa River Basin-Central Yampa River Basin-
Roan and Tavaputs Plateaus-Elkhead and Park Mountains-
Upper Yampa River Basin-Grand Valley-Debeque to Silt Corridor-
Central Colorado River Basin-Grand and Battlement Mesas-
Gore and Elk Mountains/Central Mountain Valleys-
Central Gunnison and Uncompahgre River Basin-
West Elk and Sawatch Mountains-Flat Tops-
Upper Gunnison River Valley-Uncompahgre Plateau and Dallas Divide-
Northwest San Juan Mountains-Southwest San Juan Mountains-
Paradox Valley/Lower Dolores River-
Four Corners/Upper Dolores River-Animas River Basin-
San Juan River Basin-Southeast Utah-Eastern Uinta Mountains-
Eastern Uinta Basin-Tavaputs Plateau-Arches/Grand Flat-
La Sal and Abajo Mountains-Canyonlands/Natural Bridges-
434 AM MDT Mon Aug 2 2021

This hazardous weather outlook is for eastern Utah and western
Colorado.

.DAY ONE...Today and Tonight

Widespread showers and thunderstorms are expected today with the
best potential of heavy rain and flash flooding over the higher
terrain of western Colorado and recent burn scars as deep
monsoonal moisture remains in place. Storms will continue into
the overnight hours. Expect heavy rain, frequent lightning, gusty
outflow winds to 40 mph and hail with stronger storms.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday

Scattered showers and thunderstorms can be expected each day.
Moderate to heavy rain, gusty winds and lightning will be the
primary threats with storms.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected today or tonight, however
spotters are encouraged to relay rainfall amounts or any observed
flooding to the National Weather Service in Grand Junction.

In the hours before

Special weather statement, Aug 2, 2:16 PM MDT, 2 hours 56 minutes before
Special Weather Statement
National Weather Service Grand Junction CO
216 PM MDT Mon Aug 2 2021

COZ019>021-UTZ028-022045-
Southwest San Juan Mountains CO-
Paradox Valley/Lower Dolores River CO-
Four Corners/Upper Dolores River CO-La Sal and Abajo Mountains UT-
216 PM MDT Mon Aug 2 2021

...SIGNIFICANT WEATHER ADVISORY FOR NORTHWESTERN DOLORES AND WEST
CENTRAL SAN MIGUEL COUNTIES UNTIL 245 PM MDT...

At 215 PM MDT, Doppler radar was tracking a strong thunderstorm 8
miles north of Dove Creek, moving east at 20 mph.

Half inch hail and winds in excess of 40 mph will be possible with
this storm.

Locations impacted include...
Egnar.

This includes Colorado 141 between mile markers 3 and 12.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3786 10906 3795 10902 3795 10877 3774 10880
TIME...MOT...LOC 2015Z 288DEG 18KT 3788 10896

Miller
Special weather statement, Aug 2, 2:49 PM MDT, 2 hours 23 minutes before
Special Weather Statement
National Weather Service Grand Junction CO
249 PM MDT Mon Aug 2 2021

COZ001-022115-
Lower Yampa River Basin CO-
249 PM MDT Mon Aug 2 2021

...SPECIAL WEATHER STATEMENT...

At 248 PM MDT, Doppler radar was tracking a strong thunderstorm 13
miles southwest of Rangely moving northeast at 15 mph.

Pea size  hail and winds in excess of 30 mph will be possible with
this storm.

Locations impacted include...
Rangely.

This includes the following highways...
 Colorado 64 between mile markers 14 and 16.
 Colorado 139 between mile markers 61 and 70.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3985 10887 3987 10900 3991 10904 4012 10888
      4001 10865
TIME...MOT...LOC 2048Z 214DEG 11KT 3994 10894

ERW
Local storm report, Aug 2, 3:43 PM MDT, 1 hour 29 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
343 PM MDT MON AUG 2 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0300 PM     HEAVY RAIN       2 SSW VERNAL            40.43N 109.55W
08/02/2021  M0.52 INCH       UINTAH             UT   PUBLIC

&&
Special weather statement, Aug 2, 3:55 PM MDT, 1 hour 17 minutes before
Special Weather Statement
National Weather Service Grand Junction CO
355 PM MDT Mon Aug 2 2021

COZ019-022230-
Southwest San Juan Mountains CO-
355 PM MDT Mon Aug 2 2021

...SIGNIFICANT WEATHER ADVISORY FOR CENTRAL DOLORES COUNTY UNTIL 430
PM MDT...

At 354 PM MDT, Doppler radar was tracking a strong thunderstorm 14
miles northeast of Dolores, moving east at 15 mph.

Half inch hail and winds in excess of 40 mph will be possible with
this storm.

This storm will remain over mainly rural areas of central Dolores
County.

This includes Colorado 145 near mile marker 24.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3759 10841 3769 10845 3777 10828 3759 10818
TIME...MOT...LOC 2154Z 249DEG 13KT 3766 10838

Miller
Special weather statement, Aug 2, 4:57 PM MDT, 15 minutes before
Special Weather Statement
National Weather Service Grand Junction CO
457 PM MDT Mon Aug 2 2021

UTZ029-022345-
Canyonlands/Natural Bridges UT-
457 PM MDT Mon Aug 2 2021

...SIGNIFICANT WEATHER ADVISORY FOR NORTHERN SAN JUAN COUNTY UNTIL
545 PM MDT...

At 456 PM MDT, Doppler radar was tracking a strong thunderstorm near
Canyonlands National Park, moving east at 20 mph.

Nickel size  hail and winds in excess of 40 mph will be possible with
this storm.

Locations impacted include...
Canyonlands National Park.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3841 11000 3842 11001 3850 10979 3830 10964
      3833 10996 3835 10994 3836 10995 3834 10996
      3835 10998 3839 10997 3839 10999 3836 11001
      3838 11001 3839 11003
TIME...MOT...LOC 2256Z 252DEG 16KT 3838 10999

Miller
Special weather statement, Aug 2, 5:12 PM MDT, 0 minutes before
Special Weather Statement
National Weather Service Grand Junction CO
512 PM MDT Mon Aug 2 2021

UTZ029-030000-
Canyonlands/Natural Bridges UT-
512 PM MDT Mon Aug 2 2021

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHWESTERN SAN JUAN COUNTY
UNTIL 600 PM MDT...

At 512 PM MDT, Doppler radar was tracking a strong thunderstorm 8
miles east of Halls Crossing, moving southeast at 30 mph.

Half inch hail and wind gusts up to 50 mph will be possible with
this storm.

This storm will remain over mainly rural areas of southwestern San
Juan County.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3745 11053 3757 11053 3735 11010 3733 11009
      3733 11024 3732 11024 3732 11044 3730 11044
      3730 11047 3745 11060
TIME...MOT...LOC 2312Z 309DEG 25KT 3746 11053

Miller

The office that day

Everything else NWS Grand Junction, CO issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 1, 8:37 PM MDTAreal Flood AdvisoryGJTGarfield, Mesa3 hr
Aug 2, 1:17 PM MDTAreal Flood AdvisoryGJTMesa, Montrose118 min
Aug 2, 2:16 PM MDTSpecial Weather StatementGJTDolores29 min
Aug 2, 2:30 PM MDTFlash Flood WatchGJTArchuleta, Delta, Dolores, Eagle, Garfield, Gunnison and 12 more29 hr
Aug 2, 2:49 PM MDTSpecial Weather StatementGJTRio Blanco26 min
Aug 2, 3:55 PM MDTSpecial Weather StatementGJTDolores35 min
Aug 2, 4:57 PM MDTSpecial Weather StatementGJT48 min
Aug 1, 6:35 PM MDTAreal Flood AdvisoryGJTUintah115 min
Aug 1, 6:41 PM MDTSpecial Weather StatementGJTUintah34 min
Aug 1, 7:03 PM MDTAreal Flood AdvisoryGJTGrand3 hr
Aug 1, 8:56 PM MDTFlash Flood Warning Considerable damage threatGJTGrand, San Juan109 min
Aug 1, 11:10 PM MDTFlash Flood Warning Considerable damage threatGJTGrand, San Juan3 hr
Aug 2, 1:29 PM MDTAreal Flood AdvisoryGJTSan Juan2 hr
Aug 2, 4:37 PM MDTAreal Flood AdvisoryGJTUintah2 hr

Nearby

Special Weather Statements in Utah, 2021Every 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.