Alert archive / Colorado / Flash Flood Watches in 2021
Flash Flood Watch 25, NWS Grand Junction, CO
NWS Grand Junction, CO issued this flash flood watch at Jul 30, 2021, 3:44 AM MDT for 18 counties in Colorado. It took effect at Jul 31, 2021, 11:00 AM MDT. It was in force for 12 hr.
The area
The counties it named.
The facts
- Issued
- Jul 30, 2021, 3:44 AM MDT (09:44 UTC)
- In effect from
- Jul 31, 2021, 11:00 AM MDT
- Expired
- Jul 31, 2021, 10:36 PM MDT
- In force
- 12 hr
- Issued by
- NWS Grand Junction, CO
- Flood severity
- None
Counties Archuleta County, CO, Delta County, CO, Dolores County, CO, Eagle County, CO, Garfield County, CO, Gunnison County, CO, Hinsdale County, CO, La Plata County, CO, Mesa County, CO, Moffat County, CO, Montezuma County, CO, Montrose County, CO, Ouray County, CO, Pitkin County, CO, Rio Blanco County, CO, Routt County, CO, San Juan County, CO, San Miguel County, CO
The radar
The Grand Junction radar (KGJX), 60 km from the middle of the area, began a volume at 09:43 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 00:00Z, 9.7 hours before the alert went out and 83 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.
- Mixed-layer CAPE
- 407 J/kg
- Mixed-layer CIN
- -168 J/kg
- Mixed-layer LCL
- 2854 m above ground
- 0-6 km bulk shear
- 19 kt
- 0-1 km storm-relative helicity
- -17 m²/s²
- 0-3 km storm-relative helicity
- 43 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
What forecasters said that day
The local office's own words before this flash flood watch 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 flash flood watch went out at Jul 29, 11:43 PM MDT, 4 hours 1 minute earlier.
Area forecast discussion, Jul 29, 11:43 PM MDT, 4 hours 1 minute before
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</html>Hazardous weather outlook, Jul 29, 4:57 AM MDT, 22 hours 47 minutes before
Hazardous Weather Outlook National Weather Service Grand Junction CO 457 AM MDT Thu Jul 29 2021 COZ001>014-017>023-UTZ022>025-027>029-301100- 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- 457 AM MDT Thu Jul 29 2021 This hazardous weather outlook is for eastern Utah and western Colorado. .DAY ONE...Today and Tonight Showers and thunderstorms will become more widespread today, beginning over the high terrain by late morning and drifting into lower elevations late afternoon into the evening. Lightning and heavy rainfall will be the main threats along with gusty outflow winds and hail in the stronger storms. Flash flooding is possible with heavy rainfall over portions of southwest Colorado and southeast Utah. Storms will continue into the overnight hours. .DAYS TWO THROUGH SEVEN...Friday through Wednesday Daily scattered to numerous showers and thunderstorms can be expected each day with monsoon moisture entrenched across the area. Storm activity and coverage looks to increase late this week into the weekend with better potential for storms to last through the overnight hours. Moderate to heavy rain, gusty winds and lightning will be the primary threats with storms. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be needed.
In the hours before
Special weather statement, Jul 29, 10:20 PM MDT, 5 hours 24 minutes before
Special Weather Statement National Weather Service Grand Junction CO 1020 PM MDT Thu Jul 29 2021 COZ009-011-014-017-300500- Upper Gunnison River Valley CO-Grand and Battlement Mesas CO- Uncompahgre Plateau/Dallas Divide CO- Central Gunnison and Uncompahgre River Basin CO- 1020 PM MDT Thu Jul 29 2021 ...SIGNIFICANT WEATHER ADVISORY FOR SOUTHWESTERN DELTA AND NORTH CENTRAL MONTROSE COUNTIES UNTIL 1100 PM MDT... At 1019 PM MDT, Doppler radar was tracking strong thunderstorms along a line extending from near Olathe to 11 miles southwest of Delta. Movement was northwest at 20 mph. Wind gusts of 50 to 55 mph will be possible with these storms. Locations impacted include... Delta, Orchard City, Olathe, Cory and Austin. This includes the following highways... U.S. Highway 50 in Colorado between mile markers 59 and 81. Colorado 65 between mile markers 1 and 4. Colorado 92 between mile markers 1 and 8. PRECAUTIONARY/PREPAREDNESS ACTIONS... Heavy rainfall is also occurring with these storms, and may lead to localized flooding. Do not drive your vehicle through flooded roadways. && LAT...LON 3891 10805 3876 10833 3859 10816 3864 10780 TIME...MOT...LOC 0419Z 139DEG 17KT 3867 10792 3860 10817 15
Local storm report, Jul 29, 11:30 PM MDT, 4 hours 14 minutes before
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</html>Local storm report, Jul 29, 11:34 PM MDT, 4 hours 10 minutes before
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</html>Special weather statement, Jul 29, 11:49 PM MDT, 3 hours 55 minutes before
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</html>The office that day
Everything else NWS Grand Junction, CO issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 29, 6:14 PM MDT | Special Weather Statement | GJT | Garfield | 46 min |
| Jul 29, 6:27 PM MDT | Special Weather Statement | GJT | Archuleta | 48 min |
| Jul 29, 6:32 PM MDT | Flash Flood Warning | GJT | Montezuma | 3 hr |
| Jul 29, 6:38 PM MDT | Special Weather Statement | GJT | Garfield | 52 min |
| Jul 29, 6:55 PM MDT | Areal Flood Advisory | GJT | La Plata, Montezuma | 3 hr |
| Jul 29, 7:00 PM MDT | Special Weather Statement | GJT | Moffat | 45 min |
| Jul 29, 7:11 PM MDT | Areal Flood Advisory | GJT | Garfield | 2 hr |
| Jul 29, 7:39 PM MDT | Special Weather Statement | GJT | Rio Blanco | 51 min |
| Jul 29, 7:48 PM MDT | Special Weather Statement | GJT | La Plata | 42 min |
| Jul 29, 7:50 PM MDT | Severe Thunderstorm Warning | GJT | Moffat, Rio Blanco | 25 min |
| Jul 29, 7:56 PM MDT | Special Weather Statement | GJT | Routt | 49 min |
| Jul 29, 8:25 PM MDT | Severe Thunderstorm Warning | GJT | Garfield, Rio Blanco | 35 min |
| Jul 29, 8:41 PM MDT | Special Weather Statement | GJT | Montezuma | 49 min |
| Jul 29, 8:45 PM MDT | Flash Flood Warning | GJT | Eagle, Garfield | 4 hr |
| Jul 29, 9:42 PM MDT | Special Weather Statement | GJT | Moffat | 48 min |
| Jul 29, 9:43 PM MDT | Special Weather Statement | GJT | Moffat | 47 min |
| Jul 29, 9:46 PM MDT | Areal Flood Advisory | GJT | Moffat | 3 hr |
| Jul 29, 10:20 PM MDT | Special Weather Statement | GJT | Delta | 40 min |
| Jul 29, 10:28 PM MDT | Areal Flood Advisory | GJT | Moffat | 3 hr |
| Jul 29, 10:45 PM MDT | Flash Flood Warning | GJT | Garfield, Mesa | 4 hr |
| Jul 30, 2:09 PM MDT | Special Weather Statement | GJT | Routt | 36 min |
| Jul 30, 2:22 PM MDT | Special Weather Statement | GJT | Routt | 38 min |
| Jul 30, 3:46 PM MDT | Flash Flood Warning | GJT | Eagle | 3 hr |
| Jul 30, 3:48 PM MDT | Special Weather Statement | GJT | Pitkin | 42 min |
| Jul 30, 3:57 PM MDT | Special Weather Statement | GJT | Rio Blanco | 48 min |
| Jul 30, 3:59 PM MDT | Severe Thunderstorm Warning | GJT | Pitkin | 46 min |
| Jul 30, 4:34 PM MDT | Areal Flood Advisory | GJT | Gunnison | 100 min |
| Jul 30, 4:43 PM MDT | Areal Flood Advisory | GJT | Rio Blanco | 2 hr |
| Jul 30, 4:45 PM MDT | Special Weather Statement | GJT | Rio Blanco | 45 min |
| Jul 30, 4:53 PM MDT | Special Weather Statement | GJT | Eagle | 52 min |
| Jul 30, 5:02 PM MDT | Areal Flood Advisory | GJT | Rio Blanco | 102 min |
| Jul 30, 5:22 PM MDT | Areal Flood Advisory | GJT | Eagle | 97 min |
| Jul 29, 6:17 PM MDT | Flash Flood Warning | GJT | San Juan | 3 hr |
| Jul 29, 6:31 PM MDT | Special Weather Statement | GJT | Grand | 44 min |
| Jul 29, 6:34 PM MDT | Areal Flood Advisory | GJT | San Juan | 3 hr |
| Jul 29, 6:53 PM MDT | Areal Flood Advisory | GJT | San Juan | 3 hr |
| Jul 29, 7:41 PM MDT | Areal Flood Advisory | GJT | Grand, San Juan | 3 hr |
| Jul 29, 7:44 PM MDT | Areal Flood Advisory | GJT | San Juan | 3 hr |
| Jul 29, 11:49 PM MDT | Special Weather Statement | GJT | Uintah | 41 min |
| Jul 30, 2:23 PM MDT | Special Weather Statement | GJT | Uintah | 52 min |
Nearby
Flash Flood Watches in Colorado, 2021Every flash flood watch 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.