Alert archive / Colorado / Tornado Warnings in 2017
Tornado Warning 11, NWS Denver/Boulder, CO
NWS Denver/Boulder, CO issued this tornado warning at Jun 12, 2017, 3:46 PM MDT for Weld County, Colorado. It was in force for 29 min. 2 reports came from inside the area while it was in force.
The area
The outline as issued, with what was reported inside it.
The facts
- Issued
- Jun 12, 2017, 3:46 PM MDT (21:46 UTC)
- Expired
- Jun 12, 2017, 4:15 PM MDT
- In force
- 29 min
- Issued by
- NWS Denver/Boulder, CO
- Area
- Storm-based polygon
- Tornado
- Radar indicated
- Hail
- 2.5 in
County Weld County, CO
The radar
The Cheyenne radar (KCYS), 53 km from the middle of the area, began a volume at 21:46 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.
What was reported inside it
| Time | Report | Where | Remark |
|---|---|---|---|
| Jun 12, 3:59 PM MDT | HAIL 1.25 | 5 E Nunn, CO | |
| Jun 12, 4:01 PM MDT | HAIL 1.75 | 10 E Nunn, CO |
Local storm reports filed while the alert was in force, from inside its polygon or its counties.
The watch it was issued in
The SPC watch in force over the same counties when this warning went out.
| Issued | Product | Office | Lasted |
|---|---|---|---|
| Jun 12, 1:11 PM MDT | Tornado Watch | SPC | 8 hr |
The nearest sounding before it
Denver, CO (KDEN), launched 12:00Z, 9.8 hours before the alert went out and 149 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
- 697 J/kg
- Mixed-layer CIN
- -160 J/kg
- Mixed-layer LCL
- 1130 m above ground
- 0-6 km bulk shear
- 24 kt
- 0-1 km storm-relative helicity
- 50 m²/s²
- 0-3 km storm-relative helicity
- 153 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
554
WFUS55 KBOU 122146
TORBOU
COC123-122215-
/O.NEW.KBOU.TO.W.0011.170612T2146Z-170612T2215Z/
BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Denver CO
346 PM MDT MON JUN 12 2017
The National Weather Service in Denver Colorado has issued a
* Tornado Warning for...
Northwestern Weld County in northeastern Colorado...
* Until 415 PM MDT
* At 344 PM MDT, a severe thunderstorm capable of producing a tornado
was located 5 miles northwest of Purcell, or 19 miles north of
Greeley, moving northeast at 35 mph.
HAZARD...Tornado and tennis ball size hail.
SOURCE...Radar indicated rotation.
IMPACT...Flying debris will be dangerous to those caught without
shelter. Mobile homes will be damaged or destroyed.
Damage to roofs, windows, and vehicles will occur. Tree
damage is likely.
* Locations impacted include...
Pierce, Nunn and Purcell.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.
&&
LAT...LON 4057 10470 4076 10484 4089 10448 4070 10432
TIME...MOT...LOC 2144Z 239DEG 33KT 4069 10463
TORNADO...RADAR INDICATED
HAIL...2.50IN
$$
rpk1 follow-up statement
868
WWUS55 KBOU 122200
SVSBOU
Severe Weather Statement
National Weather Service Denver CO
400 PM MDT MON JUN 12 2017
COC123-122215-
/O.CON.KBOU.TO.W.0011.000000T0000Z-170612T2215Z/
Weld CO-
400 PM MDT MON JUN 12 2017
...A TORNADO WARNING REMAINS IN EFFECT UNTIL 415 PM MDT FOR
NORTHWESTERN WELD COUNTY...
At 359 PM MDT, a severe thunderstorm capable of producing a tornado
was located 10 miles north of Purcell, or 27 miles northeast of
Greeley, moving northeast at 35 mph.
HAZARD...Tornado and tennis ball size hail.
SOURCE...Radar indicated rotation.
IMPACT...Flying debris will be dangerous to those caught without
shelter. Mobile homes will be damaged or destroyed. Damage
to roofs, windows, and vehicles will occur. Tree damage is
likely.
This tornadic thunderstorm will remain over mainly rural areas of
northwestern Weld County.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.
&&
LAT...LON 4062 10469 4077 10480 4089 10448 4071 10434
TIME...MOT...LOC 2159Z 213DEG 29KT 4078 10453
TORNADO...RADAR INDICATED
HAIL...2.50IN
$$
RpkThe office that day
Everything else NWS Denver/Boulder, CO issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 11, 9:09 PM MDT | Severe Thunderstorm Warning | BOU | Phillips | 51 min |
| Jun 11, 9:13 PM MDT | Severe Thunderstorm Warning | BOU | Logan | 28 min |
| Jun 12, 11:07 AM MDT | Areal Flood Advisory | BOU | Grand | 24 hr |
| Jun 12, 2:29 PM MDT | Severe Thunderstorm Warning | BOU | Larimer, Weld | 46 min |
| Jun 12, 2:36 PM MDT | Severe Thunderstorm Warning | BOU | Larimer | 39 min |
| Jun 12, 3:08 PM MDT | Severe Thunderstorm Warning | BOU | Larimer | 26 min |
| Jun 12, 3:15 PM MDT | Tornado Warning | BOU | Weld | 30 min |
| Jun 12, 3:26 PM MDT | Severe Thunderstorm Warning | BOU | Weld | 36 min |
| Jun 12, 3:45 PM MDT | Tornado Warning | BOU | Weld | 30 min |
| Jun 12, 4:13 PM MDT | Tornado Warning | BOU | Weld | 32 min |
| Jun 12, 4:35 PM MDT | Tornado Warning | BOU | Weld | 25 min |
Nearby
Tornado Warnings in Colorado, 2017Every tornado warning in 2017Tornadoes in 2017
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.