Alert archive / Idaho / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 21, NWS Boise, ID

August 30, 2017Ada County, Boise County, Elmore County, Idaho

NWS Boise, ID issued this severe thunderstorm warning at Aug 30, 2017, 4:49 PM MDT for Ada County, Boise County, Elmore County, Idaho. It was in force for 26 min. 1 report 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: Aug 30, 2017, 4:49 PM MDT (22:49 UTC)
Expired: Aug 30, 2017, 5:15 PM MDT
In force: 26 min
Issued by: NWS Boise, ID
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

Counties Ada County, ID, Boise County, ID, Elmore County, ID

The radar

The Boise radar (KCBX), 33 km from the middle of the area, began a volume at 22:50 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
Aug 30, 5:00 PM MDT	TSTM WND DMG	Boise, ID	POWER OUTAGE IN DOWNTOWN BOISE.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Boise Airport, ID (KBOI), launched 12:00Z, 10.8 hours before the alert went out and 28 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: 3532 m above ground
0-6 km bulk shear: 24 kt
0-1 km storm-relative helicity: -61 m²/s²
0-3 km storm-relative helicity: -45 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

480 
WUUS55 KBOI 302249
SVRBOI
IDC001-015-039-302315-
/O.NEW.KBOI.SV.W.0021.170830T2249Z-170830T2315Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Boise ID
449 PM MDT WED AUG 30 2017

The National Weather Service in Boise has issued a

* Severe Thunderstorm Warning for...
  Northeastern Ada County in southwestern Idaho...
  Southwestern Boise County in southwestern Idaho...
  Central Elmore County in southwestern Idaho...

* Until 515 PM MDT.

* At 447 PM MDT, severe thunderstorms were located along a line
  extending from near Aldape Summit to 6 miles east of Boise Stage
  Stop, moving east at 30 mph.

  HAZARD...60 mph wind gusts. 

  SOURCE...Radar indicated. Boise Airport tower reported 67 mph wind 
           gust with this storm.           

  IMPACT...Expect damage to roofs, siding, and trees. 

* Severe thunderstorms will be near...
  Lucky Peak Reservoir and Lucky Peak Spring Shores Marina around 
  500 PM MDT. 
  Prairie, Danskin Peak, Arrowrock Dam and Arrowrock Reservoir 
  around 510 PM MDT. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

If on or near Lucky Peak Reservoir, get away from the water and move 
indoors or inside a vehicle. Remember, lightning can strike out to 
15 miles from the parent thunderstorm. If you can hear thunder, you 
are close enough to be struck by lightning. Move to safe shelter 
now!  Do not be caught on the water in a thunderstorm.

When safe to do so, please relay storm reports to the National
Weather Service in Boise via local law enforcement, or National
Weather Service Boise Facebook and Twitter accounts.

&&

LAT...LON 4382 11590 4339 11531 4331 11590 4363 11627
TIME...MOT...LOC 2247Z 251DEG 25KT 4361 11611 4340 11587 

HAIL...<.75IN
WIND...60MPH
 
$$

KA

1 follow-up statement

553 
WWUS55 KBOI 302307
SVSBOI

Severe Weather Statement
National Weather Service Boise ID
507 PM MDT WED AUG 30 2017

IDC001-015-039-302315-
/O.CON.KBOI.SV.W.0021.000000T0000Z-170830T2315Z/
Ada ID-Boise ID-Elmore ID-
507 PM MDT WED AUG 30 2017

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 515 PM MDT
FOR NORTHEASTERN ADA...SOUTHWESTERN BOISE AND CENTRAL ELMORE
COUNTIES...

At 503 PM MDT, severe thunderstorms were located along a line 
extending from Aldape Summit to 6 miles west of Danskin Peak, or in 
other words over northeast Ada County moving into southern 
Boise and west-central Elmore counties, moving east at 30 mph.

HAZARD...60+ mph wind gusts. 

SOURCE...Radar indicated. Also, Boise tower reported a gust to 67 
         mph at 448 pm MDT.

IMPACT...Expect damage to roofs, siding, and trees. 

These severe storms will be near...
  Prairie, Danskin Peak, Arrowrock Reservoir and Twin Springs around 
  510 PM MDT. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

If on or near Lucky Peak Reservoir, get away from the water and move 
indoors or inside a vehicle. remember, lightning can strike out to 
15 miles from the parent thunderstorm. If you can hear thunder, you 
are close enough to be struck by lightning. Move to safe shelter 
now!  Do not be caught on the water in a thunderstorm.

When safe to do so, please relay storm reports to the National
Weather Service in Boise via local law enforcement, or National
Weather Service Boise Facebook and Twitter accounts.

&&

LAT...LON 4382 11590 4339 11531 4331 11590 4363 11627
TIME...MOT...LOC 2303Z 251DEG 25KT 4363 11603 4342 11579 

HAIL...<.75IN
WIND...60MPH
 
$$

SP

The office that day

Everything else NWS Boise, ID issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 30, 8:26 AM MDT	Red Flag Warning	BOI	Adams, Boise, Camas, Elmore, Gem, Gooding and 7 more	17 hr
Aug 30, 4:09 PM MDT	Special Weather Statement	BOI	Canyon, Gem, Payette	51 min
Aug 30, 4:20 PM MDT	Special Weather Statement	BOI	Ada	40 min
Aug 30, 4:22 PM MDT	Special Weather Statement	BOI	Elmore	53 min
Aug 30, 5:14 PM MDT	Severe Thunderstorm Warning	BOI	Boise, Camas, Elmore	46 min

Nearby

Severe Thunderstorm Warnings in Idaho, 2017 Every severe thunderstorm warning 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.