Alert archive / Colorado / Tornado Warnings in 2015

Tornado Warning 7, NWS Denver/Boulder, CO

May 7, 2015Weld County, Colorado

NWS Denver/Boulder, CO issued this tornado warning at May 7, 2015, 6:41 PM MDT for Weld County, Colorado. It was in force for 34 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: May 7, 2015, 6:41 PM MDT (00:41 UTC)
Expired: May 7, 2015, 7:15 PM MDT
In force: 34 min
Issued by: NWS Denver/Boulder, CO
Area: Storm-based polygon
Tornado: Observed
Hail: 0.75 in

County Weld County, CO

The radar

The Denver radar (KFTG), 38 km from the middle of the area, began a volume at 00:44 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

Denver, CO (KDEN), launched 00:00Z, 0.7 hours before the alert went out and 135 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1286 m above ground
0-6 km bulk shear: 30 kt
0-1 km storm-relative helicity: 35 m²/s²
0-3 km storm-relative helicity: 98 m²/s²
Significant tornado parameter: -0.0
Supercell composite: -0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

707 
WFUS55 KBOU 080041
TORBOU
COC123-080115-
/O.NEW.KBOU.TO.W.0007.150508T0041Z-150508T0115Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE DENVER CO
641 PM MDT THU MAY 7 2015

THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A

* TORNADO WARNING FOR...
  SOUTHERN WELD COUNTY IN NORTHEASTERN COLORADO...

* UNTIL 715 PM MDT

* AT 640 PM MDT...A CONFIRMED WEAK TORNADO WAS LOCATED NEAR FORT 
  LUPTON... OR 23 MILES NORTH OF DENVER...AND IS NEARLY STATIONARY.

  HAZARD...DAMAGING TORNADO. 

  SOURCE...PUBLIC CONFIRMED TORNADO. 

  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...
  FORT LUPTON.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TO REPEAT...A WEAK TORNADO IS ON THE GROUND. TAKE COVER NOW! MOVE TO 
A BASEMENT OR AN INTERIOR ROOM ON THE LOWEST FLOOR OF A STURDY 
BUILDING. AVOID WINDOWS. IF YOU ARE IN A MOBILE HOME...A VEHICLE OR 
OUTDOORS...MOVE TO THE CLOSEST SUBSTANTIAL SHELTER AND PROTECT 
YOURSELF FROM FLYING DEBRIS.

&&

LAT...LON 4002 10484 4009 10485 4016 10473 4005 10471
TIME...MOT...LOC 0040Z 255DEG 0KT 4004 10480 

TORNADO...OBSERVED
HAIL...<.75IN

$$

KRIEDERMAN

2 follow-up statements

986 
WWUS55 KBOU 080056
SVSBOU

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
656 PM MDT THU MAY 7 2015

COC123-080115-
/O.CON.KBOU.TO.W.0007.000000T0000Z-150508T0115Z/
WELD CO-
656 PM MDT THU MAY 7 2015

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 715 PM MDT FOR SOUTHERN
WELD COUNTY...
    
AT 654 PM MDT...A CONFIRMED WEAK LANDSPOUT TORNADO LOCATED NEAR FORT 
LUPTON...OR 23 MILES NORTH OF DENVER...HAS SINCE RETREATED BACK UP 
INTO A FUNNEL CLOUD...BUT THERE IS STILL A CHANCE IT COULD DROP BACK 
DOWN AGAIN. 

HAZARD...WEAK TORNADO. 

SOURCE...PUBLIC CONFIRMED WEAK TORNADO. 

IMPACT...EXPECT DAMAGE TO MOBILE HOMES...ROOFS AND VEHICLES. 

LOCATIONS IMPACTED INCLUDE...
FORT LUPTON.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TO REPEAT...A TORNADO IS ON THE GROUND. TAKE COVER NOW! MOVE TO A
BASEMENT OR AN INTERIOR ROOM ON THE LOWEST FLOOR OF A STURDY
BUILDING. AVOID WINDOWS. IF IN A MOBILE HOME...A VEHICLE OR
OUTDOORS...MOVE TO THE CLOSEST SUBSTANTIAL SHELTER AND PROTECT
YOURSELF FROM FLYING DEBRIS.

&&

LAT...LON 4002 10484 4009 10485 4016 10473 4005 10471
TIME...MOT...LOC 0054Z 255DEG 0KT 4004 10479 

TORNADO...OBSERVED
HAIL...<.75IN

$$

KRIEDERMAN

424 
WWUS55 KBOU 080106
SVSBOU

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE DENVER CO
706 PM MDT THU MAY 7 2015

COC123-080116-
/O.EXP.KBOU.TO.W.0007.000000T0000Z-150508T0115Z/
WELD CO-
706 PM MDT THU MAY 7 2015

...THE TORNADO WARNING FOR SOUTHERN WELD COUNTY WILL EXPIRE AT 715 PM
MDT...
                
THE STORM WHICH PROMPTED THE WARNING HAS WEAKENED BELOW SEVERE
LIMITS...AND NO LONGER APPEARS CAPABLE OF PRODUCING A TORNADO.
THEREFORE THE WARNING WILL BE ALLOWED TO EXPIRE.  HOWEVER HEAVY RAIN
IS STILL POSSIBLE WITH THIS THUNDERSTORM.

LAT...LON 4002 10484 4009 10485 4016 10473 4005 10471
TIME...MOT...LOC 0102Z 255DEG 0KT 4004 10479 

$$

KRIEDERMAN

The office that day

Everything else NWS Denver/Boulder, CO issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 8, 11:08 AM MDT	Areal Flood Advisory	BOU	Adams, Arapahoe, Boulder, Broomfield, Clear Creek, Denver and 10 more	60 hr
May 8, 11:50 AM MDT	Special Weather Statement	BOU	Elbert	55 min
May 8, 1:13 PM MDT	Special Weather Statement	BOU	Douglas, Jefferson	47 min
May 8, 2:16 PM MDT	Areal Flood Advisory	BOU	Jefferson	89 min

Nearby

Tornado Warnings in Colorado, 2015 Every tornado warning in 2015 Tornadoes in 2015

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.