Alert archive / Colorado / Flash Flood Warnings in 2018
Flash Flood Warning 20, NWS Grand Junction, CO
NWS Grand Junction, CO issued this flash flood warning at Jul 24, 2018, 1:41 PM MDT for La Plata County, Colorado. It was in force for 4 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
- Jul 24, 2018, 1:41 PM MDT (19:41 UTC)
- Expired
- Jul 24, 2018, 5:15 PM MDT
- In force
- 4 hr
- Issued by
- NWS Grand Junction, CO
- Area
- Storm-based polygon
- Flood severity
- None
County La Plata County, CO
The radar
The Grand Junction radar (KGJX), 200 km from the middle of the area, began a volume at 19:43 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
Albuquerq/Krtlnd, NM (KABQ), launched 12:00Z, 7.7 hours before the alert went out and 273 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 1766 m above ground
- 0-6 km bulk shear
- 19 kt
- 0-1 km storm-relative helicity
- -3 m²/s²
- 0-3 km storm-relative helicity
- 24 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 Jul 24, 11:52 AM MDT, 1 hour 49 minutes earlier.
Area forecast discussion, Jul 24, 11:52 AM MDT, 1 hour 49 minutes before
Area Forecast Discussion National Weather Service Grand Junction CO 1152 AM MDT Tue Jul 24 2018 .SHORT TERM...(Today through Wednesday) Issued at 303 AM MDT Tue Jul 24 2018 The center of broad high pressure will shift from western New Mexico to Arizona today through Wednesday, signaling the interruption of another weak and unsatisfying monsoonal surge of the past few days. This afternoon and evening will still see monsoonal moisture flowing into southern CO producing showers and thunderstorms but that flow should be interrupted by Wed. Also, a shortwave trough in the westerlies over the Northern Rockies will increase drying from the west and north and continue forcing the remnants of the monsoonal moisture plume to curve to the east over central CO. This will leave northeast UT and the northern half of CO drier today through Wed. Wednesday will see the flow aloft becoming more northwesterly as the high moves further west and low pressure deepens over the midwest. There will still be showers and thunderstorms fueled by daytime heating acting on the moisture trapped within the high, with highest coverage over southern CO. .LONG TERM...(Wednesday night through Monday) Issued at 303 AM MDT Tue Jul 24 2018 Once the high pressure center migrates west it remains quasi- stationary, centered over northwestern Arizona and southern Nevada according to a consensus of the medium range models. In this position moisture will slowly erode across the area as drier air to the northwest infiltrates the region. In response, eastern Utah and western Colorado will experience a decrease in areal coverage of thunderstorms during the remainder of the week, through the weekend and into early next week. Not only will showers and thunderstorms become more scarce, they will become higher based, producing strong outflow winds but little measurable precipitation. Afternoon highs during this period will remain hot with little day to day variability, while overnight lows cool slightly as the atmosphere dries. && .AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon) Issued at 1152 AM MDT Tue Jul 24 2018 Convection today started with an MCV across the Paradox valley which has since weakened, but a few thunderstorms have developed with one heading toward KTEX. Most activity should develop south of I-70, but outflow boundaries may develop later to trigger isolated showers and thunderstorms elsewhere. Convective activity may continue past 06z tonight for some nocturnal activity. Gusty outflow winds of 30 to 45 mph will be possible with thunderstorms. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...None. UT...None. && SHORT TERM...CC LONG TERM...NL AVIATION...JAM
Hazardous weather outlook, Jul 24, 2:23 AM MDT, 11 hours 18 minutes before
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</html>In the hours before
Special weather statement, Jul 24, 1:07 PM MDT, 34 minutes before
Special Weather Statement National Weather Service Grand Junction CO 107 PM MDT TUE JUL 24 2018 COZ019-241945- Southwest San Juan Mountains CO- 107 PM MDT TUE JUL 24 2018 ...SIGNIFICANT WEATHER ADVISORY FOR SOUTHWESTERN HINSDALE... SOUTHEASTERN SAN JUAN AND NORTHEASTERN LA PLATA COUNTIES UNTIL 145 PM MDT... At 107 PM MDT, Doppler radar was tracking a strong thunderstorm 10 miles south of Silverton, or 27 miles north of Durango, moving southeast at 20 mph. Dime size hail and winds in excess of 40 mph will be possible with this storm. Locations impacted include... Elk Park. This includes U.S. Highway 550 in Colorado between mile markers 48 and 66. 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. Frequent cloud to ground lightning is occurring with this storm. Lightning can strike 10 miles away from a thunderstorm. Seek a safe shelter inside a building or vehicle. && LAT...LON 3763 10785 3778 10773 3760 10727 3737 10744 TIME...MOT...LOC 1907Z 301DEG 19KT 3767 10772 MDA
The office that day
Everything else NWS Grand Junction, CO issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 23, 6:00 PM MDT | Special Weather Statement | GJT | 45 min | |
| Jul 24, 1:07 PM MDT | Special Weather Statement | GJT | San Juan | 38 min |
| Jul 24, 2:28 PM MDT | Flash Flood Watch | GJT | Archuleta, Dolores, Hinsdale, La Plata, Montezuma, San Juan and 1 more | 32 hr |
| Jul 24, 2:32 PM MDT | Areal Flood Advisory | GJT | Archuleta, Hinsdale | 3 hr |
| Jul 24, 2:51 PM MDT | Areal Flood Advisory | GJT | Dolores, La Plata, Montezuma | 3 hr |
| Jul 24, 4:25 PM MDT | Areal Flood Advisory | GJT | San Juan | 3 hr |
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.