Alert archive / Colorado / Special Weather Statements in 2021

Special Weather Statement, NWS Grand Junction, CO

July 30, 2021Routt County, Colorado

NWS Grand Junction, CO issued this special weather statement at Jul 30, 2021, 2:09 PM MDT for Routt County, Colorado. It was in force for 36 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
Jul 30, 2021, 2:09 PM MDT (20:09 UTC)
Expired
Jul 30, 2021, 2:45 PM MDT
In force
36 min
Issued by
NWS Grand Junction, CO

County Routt County, CO

The radar

The Grand Junction radar (KGJX), 166 km from the middle of the area, began a volume at 20:10 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, 8.2 hours before the alert went out and 175 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 2021-07-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 28 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 2021-07-30The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 16 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
28 J/kg
Mixed-layer CIN
-252 J/kg
Mixed-layer LCL
1537 m above ground
0-6 km bulk shear
15 kt
0-1 km storm-relative helicity
16 m²/s²
0-3 km storm-relative helicity
101 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 Jul 30, 11:48 AM MDT, 2 hours 21 minutes earlier.

Area forecast discussion, Jul 30, 11:48 AM MDT, 2 hours 21 minutes before
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Hazardous weather outlook, Jul 30, 4:53 AM MDT, 9 hours 16 minutes before
Hazardous Weather Outlook
National Weather Service Grand Junction CO
453 AM MDT Fri Jul 30 2021

COZ001>014-017>023-UTZ022>025-027>029-311100-
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-
453 AM MDT Fri Jul 30 2021

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

.DAY ONE...Today and Tonight

Another round of widespread showers and thunderstorms expected
today with the focus shifting more over western Colorado for the
best potential for heavy rain and flash flooding. Monsoon moisture
will remain entrenched over the region with storm activity
continuing into the overnight hours. Expect heavy rain, frequent
lightning, gusty outflow winds to 40 kts and small hail with
stronger storms.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday

Daily widespread to numerous showers and thunderstorms can be
expected each day through early next week, with monsoon moisture
entrenched across the area. Moderate to heavy rain, gusty winds
and lightning will be the primary threats with storms. A downturn
is possible mid to late next week.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed.

In the hours before

Local storm report, Jul 30, 10:15 AM MDT, 3 hours 54 minutes before
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Local storm report, Jul 30, 11:59 AM MDT, 2 hours 10 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
1159 AM MDT FRI JUL 30 2021

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

1230 AM     HEAVY RAIN       8 NW MAESER             40.56N 109.69W
07/30/2021  M1.50 INCH       UINTAH             UT   PUBLIC

            RAIN FELL IN AROUND 20 MINUTES.

&&

NL
Special weather statement, Jul 30, 2:09 PM MDT, 0 minutes before
Special Weather Statement
National Weather Service Grand Junction CO
209 PM MDT Fri Jul 30 2021

COZ002-005-013-302045-
Flat Tops CO-Upper Yampa River Basin CO-Central Yampa River Basin CO-
209 PM MDT Fri Jul 30 2021

...SIGNIFICANT WEATHER ADVISORY FOR WEST CENTRAL ROUTT COUNTY UNTIL
245 PM MDT...

At 209 PM MDT, Doppler radar was tracking a strong thunderstorm 9
miles west of Oak Creek moving northeast at 10 mph.

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

This storm will remain over mainly rural areas of west central Routt
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 4022 10711 4024 10718 4032 10728 4048 10722
      4034 10695
TIME...MOT...LOC 2009Z 211DEG 10KT 4031 10712

ERW

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 29, 6:14 PM MDTSpecial Weather StatementGJTGarfield46 min
Jul 29, 6:27 PM MDTSpecial Weather StatementGJTArchuleta48 min
Jul 29, 6:32 PM MDTFlash Flood WarningGJTMontezuma3 hr
Jul 29, 6:38 PM MDTSpecial Weather StatementGJTGarfield52 min
Jul 29, 6:55 PM MDTAreal Flood AdvisoryGJTLa Plata, Montezuma3 hr
Jul 29, 7:00 PM MDTSpecial Weather StatementGJTMoffat45 min
Jul 29, 7:11 PM MDTAreal Flood AdvisoryGJTGarfield2 hr
Jul 29, 7:39 PM MDTSpecial Weather StatementGJTRio Blanco51 min
Jul 29, 7:48 PM MDTSpecial Weather StatementGJTLa Plata42 min
Jul 29, 7:50 PM MDTSevere Thunderstorm WarningGJTMoffat, Rio Blanco25 min
Jul 29, 7:56 PM MDTSpecial Weather StatementGJTRoutt49 min
Jul 29, 8:25 PM MDTSevere Thunderstorm WarningGJTGarfield, Rio Blanco35 min
Jul 29, 8:41 PM MDTSpecial Weather StatementGJTMontezuma49 min
Jul 29, 8:45 PM MDTFlash Flood Warning EmergencyConsiderable damage threatGJTEagle, Garfield4 hr
Jul 29, 9:42 PM MDTSpecial Weather StatementGJTMoffat48 min
Jul 29, 9:43 PM MDTSpecial Weather StatementGJTMoffat47 min
Jul 29, 9:46 PM MDTAreal Flood AdvisoryGJTMoffat3 hr
Jul 29, 10:20 PM MDTSpecial Weather StatementGJTDelta40 min
Jul 29, 10:28 PM MDTAreal Flood AdvisoryGJTMoffat3 hr
Jul 29, 10:45 PM MDTFlash Flood Warning Considerable damage threatGJTGarfield, Mesa4 hr
Jul 30, 3:44 AM MDTFlash Flood WatchGJTArchuleta, Delta, Dolores, Eagle, Garfield, Gunnison and 12 more43 hr
Jul 30, 2:22 PM MDTSpecial Weather StatementGJTRoutt38 min
Jul 30, 3:46 PM MDTFlash Flood WarningGJTEagle3 hr
Jul 30, 3:48 PM MDTSpecial Weather StatementGJTPitkin42 min
Jul 30, 3:57 PM MDTSpecial Weather StatementGJTRio Blanco48 min
Jul 30, 3:59 PM MDTSevere Thunderstorm WarningGJTPitkin46 min
Jul 30, 4:34 PM MDTAreal Flood AdvisoryGJTGunnison100 min
Jul 30, 4:43 PM MDTAreal Flood AdvisoryGJTRio Blanco2 hr
Jul 30, 4:45 PM MDTSpecial Weather StatementGJTRio Blanco45 min
Jul 30, 4:53 PM MDTSpecial Weather StatementGJTEagle52 min
Jul 30, 5:02 PM MDTAreal Flood AdvisoryGJTRio Blanco102 min
Jul 30, 5:22 PM MDTAreal Flood AdvisoryGJTEagle97 min
Jul 29, 6:17 PM MDTFlash Flood WarningGJTSan Juan3 hr
Jul 29, 6:31 PM MDTSpecial Weather StatementGJTGrand44 min
Jul 29, 6:34 PM MDTAreal Flood AdvisoryGJTSan Juan3 hr
Jul 29, 6:53 PM MDTAreal Flood AdvisoryGJTSan Juan3 hr
Jul 29, 7:41 PM MDTAreal Flood AdvisoryGJTGrand, San Juan3 hr
Jul 29, 7:44 PM MDTAreal Flood AdvisoryGJTSan Juan3 hr
Jul 29, 11:49 PM MDTSpecial Weather StatementGJTUintah41 min
Jul 30, 2:23 PM MDTSpecial Weather StatementGJTUintah52 min

Nearby

Special Weather Statements in Colorado, 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.