Alert archive / Colorado / Flash Flood Warnings in 2018
Flash Flood Warning 27, NWS Grand Junction, CO
NWS Grand Junction, CO issued this flash flood warning at Aug 21, 2018, 3:41 PM MDT for Mesa County, Montrose County, Colorado. It was in force for 3 hr. No storm report in the archive falls inside the area while it was in force.
The area
The counties it named.
The facts
- Issued
- Aug 21, 2018, 3:41 PM MDT (21:41 UTC)
- Expired
- Aug 21, 2018, 6:45 PM MDT
- In force
- 3 hr
- Issued by
- NWS Grand Junction, CO
- Area
- Storm-based polygon
- Flood severity
- None
Counties Mesa County, CO, Montrose County, CO
The radar
The Grand Junction radar (KGJX), 41 km from the middle of the area, began a volume at 21:41 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, 9.7 hours before the alert went out and 48 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
- 11 J/kg
- Mixed-layer CIN
- -403 J/kg
- Mixed-layer LCL
- 2499 m above ground
- 0-6 km bulk shear
- 37 kt
- 0-1 km storm-relative helicity
- 11 m²/s²
- 0-3 km storm-relative helicity
- 121 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 warning 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 warning went out at Aug 21, 3:16 PM MDT, 25 minutes earlier.
Area forecast discussion, Aug 21, 3:16 PM MDT, 25 minutes before
<!doctype html>
<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>
<p class="small" id="detail">
If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
</p>
</section>
</main>
<script src="index.js"></script>
</body>
</html>Hazardous weather outlook, Aug 21, 5:47 AM MDT, 9 hours 54 minutes before
Hazardous Weather Outlook National Weather Service Grand Junction CO 547 AM MDT Tue Aug 21 2018 COZ001>014-017>023-UTZ022>025-027>029-221200- 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- 547 AM MDT Tue Aug 21 2018 This hazardous weather outlook is for eastern Utah and western Colorado. .DAY ONE...Today and Tonight Showers and thunderstorms will be common across the entire forecast area today as monsoonal moisture has returned. Some of the convection will be heavy. A flash flood watch has been issued for the burn scars across the area as low amounts of rainfall can create flash flooding, mud slides, and debris flows. Rainfall will continue overnight. .DAYS TWO THROUGH SEVEN...Wednesday through Monday Shower and storms will continue into Wednesday bringing more precipitation to the area. Drying conditions will kick in Thursday and Friday before another round of showers and storms moves in for the weekend. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be needed.
In the hours before
Local storm report, Aug 21, 2:58 PM MDT, 43 minutes before
<!doctype html>
<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>
<p class="small" id="detail">
If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
</p>
</section>
</main>
<script src="index.js"></script>
</body>
</html>Local storm report, Aug 21, 3:10 PM MDT, 31 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
310 PM MDT TUE AUG 21 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0256 PM TSTM WND GST CANYONLANDS FIELD AIRPO 38.76N 109.75W
08/21/2018 M59 MPH GRAND UT ASOS
ASOS STATION CNY, CANYONLANDS FIELD AIRPORT.
&&Special weather statement, Aug 21, 3:14 PM MDT, 27 minutes before
Special Weather Statement
National Weather Service Grand Junction CO
314 PM MDT TUE AUG 21 2018
UTZ027-212200-
Arches/Grand Flat UT-
314 PM MDT TUE AUG 21 2018
...SIGNIFICANT WEATHER ADVISORY FOR CENTRAL GRAND COUNTY UNTIL 400 PM
MDT...
At 313 PM MDT, Doppler radar was tracking a strong thunderstorm 20
miles northwest of Castle Valley, moving east at 30 mph.
Half inch hail and wind gusts of 50 to 55 mph will be possible with
this storm.
Locations impacted include...
Cisco and the northern end of Arches National Park.
This includes the following highways...
Interstate 70 in Utah between mile markers 195 and 212.
Utah 128 between mile markers 31 and 44.
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 3879 10970 3888 10973 3906 10935 3895 10926
3882 10925
TIME...MOT...LOC 2113Z 253DEG 25KT 3886 10963
CharnickLocal storm report, Aug 21, 3:20 PM MDT, 21 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
320 PM MDT TUE AUG 21 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0315 PM TSTM WND GST HOPKINS FIELD AP, NUCLA 38.24N 108.56W
08/21/2018 M55 MPH MONTROSE CO MESONET
MESONET STATION AIB, HOPKINS FIELD AP,
NUCLA.
&&Special weather statement, Aug 21, 3:25 PM MDT, 16 minutes before
Special Weather Statement
National Weather Service Grand Junction CO
325 PM MDT TUE AUG 21 2018
COZ011-017-018-020-UTZ028-212215-
Uncompahgre Plateau/Dallas Divide CO-
Central Gunnison and Uncompahgre River Basin CO-
Paradox Valley/Lower Dolores River CO-
Northwestern San Juan Mountains CO-La Sal and Abajo Mountains UT-
325 PM MDT TUE AUG 21 2018
...SIGNIFICANT WEATHER ADVISORY FOR NORTHWESTERN OURAY...NORTH
CENTRAL SAN MIGUEL...SOUTHWESTERN MESA AND WESTERN MONTROSE COUNTIES
UNTIL 415 PM MDT...
At 324 PM MDT, Doppler radar was tracking a line of strong winds and
embedded thunderstorms along a line extending from 11 miles east of
La Sal to near Nucla to 10 miles west of Sawpit. Movement of this
line was northeast at 35 mph.
Wind gusts of 50 to 55 mph will be possible with these storms and
along this line of stronger winds.
Locations impacted include...
Nucla, Naturita, Norwood, Escalante Forks, Paradox, Redvale,
Vancorum, Bedrock and Uravan.
This includes the following highways...
Colorado 90 between mile markers 1 and 29, and near mile marker 33.
Colorado 141 between mile markers 53 and 109, and between mile
markers 113 and 115.
Colorado 145 between mile markers 88 and 116.
LAT...LON 3873 10894 3861 10829 3831 10792 3789 10822
3820 10851 3829 10907
TIME...MOT...LOC 2124Z 204DEG 30KT 3834 10896 3826 10848 3799 10819
15Special weather statement, Aug 21, 3:26 PM MDT, 15 minutes before
Special Weather Statement
National Weather Service Grand Junction CO
326 PM MDT TUE AUG 21 2018
UTZ027>029-212200-
La Sal and Abajo Mountains UT-Arches/Grand Flat UT-
Canyonlands/Natural Bridges UT-
326 PM MDT TUE AUG 21 2018
...SIGNIFICANT WEATHER ADVISORY FOR NORTHEASTERN SAN JUAN COUNTY
UNTIL 400 PM MDT...
At 325 PM MDT, Doppler radar was tracking a strong thunderstorm 12
miles southwest of Spanish Valley, or 14 miles south of Moab, moving
northeast at 35 mph.
Dime size hail and wind gusts of 50 to 55 mph will be possible with
this storm.
Locations impacted include...
Spanish Valley and Grand Co Arpt.
This includes U.S. Highway 191 in Utah between mile markers 108 and
123.
LAT...LON 3828 10959 3839 10972 3858 10950 3854 10935
3842 10930
TIME...MOT...LOC 2125Z 229DEG 30KT 3836 10961
CharnickThe office that day
Everything else NWS Grand Junction, CO issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 20, 8:35 PM MDT | Special Weather Statement | GJT | 40 min | |
| Aug 21, 4:02 AM MDT | Flash Flood Watch | GJT | Archuleta, Delta, Dolores, Eagle, Garfield, Hinsdale and 11 more | 44 hr |
| Aug 21, 10:50 AM MDT | Special Weather Statement | GJT | Mesa | 25 min |
| Aug 21, 11:08 AM MDT | Special Weather Statement | GJT | Mesa | 52 min |
| Aug 21, 11:19 AM MDT | Special Weather Statement | GJT | Mesa | 26 min |
| Aug 21, 11:36 AM MDT | Severe Thunderstorm Warning | GJT | Mesa | 24 min |
| Aug 21, 11:53 AM MDT | Severe Thunderstorm Warning | GJT | Garfield, Mesa | 37 min |
| Aug 21, 12:00 PM MDT | Severe Thunderstorm Warning | GJT | Mesa | 16 min |
| Aug 21, 12:29 PM MDT | Severe Thunderstorm Warning | GJT | Garfield, Mesa | 46 min |
| Aug 21, 12:57 PM MDT | Special Weather Statement | GJT | Mesa | 33 min |
| Aug 21, 1:09 PM MDT | Severe Thunderstorm Warning | GJT | Garfield, Mesa | 36 min |
| Aug 21, 1:26 PM MDT | Special Weather Statement | GJT | Pitkin | 34 min |
| Aug 21, 1:48 PM MDT | Special Weather Statement | GJT | Garfield | 42 min |
| Aug 21, 2:18 PM MDT | Special Weather Statement | GJT | Dolores | 42 min |
| Aug 21, 2:33 PM MDT | Special Weather Statement | GJT | 27 min | |
| Aug 21, 3:25 PM MDT | Special Weather Statement | GJT | Montrose | 50 min |
| Aug 21, 3:26 PM MDT | Special Weather Statement | GJT | 34 min | |
| Aug 21, 5:19 PM MDT | Areal Flood Advisory | GJT | Mesa | 3 hr |
| Aug 21, 10:59 AM MDT | Special Weather Statement | GJT | Grand | 46 min |
| Aug 21, 11:14 AM MDT | Severe Thunderstorm Warning | GJT | Grand, Uintah | 46 min |
| Aug 21, 1:27 PM MDT | Special Weather Statement | GJT | Grand | 48 min |
| Aug 21, 2:14 PM MDT | Special Weather Statement | GJT | San Juan | 46 min |
| Aug 21, 2:38 PM MDT | Special Weather Statement | GJT | Grand | 52 min |
| Aug 21, 2:47 PM MDT | Special Weather Statement | GJT | Grand | 28 min |
| Aug 21, 3:14 PM MDT | Special Weather Statement | GJT | Grand | 46 min |
Nearby
Flash Flood Warnings in Colorado, 2018Every flash flood warning in 2018
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.