Alert archive / Idaho / Special Weather Statements in 2021

Special Weather Statement, NWS Pocatello, ID

February 20, 20214 counties in Idaho

NWS Pocatello, ID issued this special weather statement at Feb 20, 2021, 10:08 AM MST for 4 counties in Idaho. 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 outline as issued.

The facts

Issued
Feb 20, 2021, 10:08 AM MST (17:08 UTC)
Expired
Feb 20, 2021, 1:00 PM MST
In force
3 hr
Issued by
NWS Pocatello, ID

Counties Bonneville County, ID, Fremont County, ID, Madison County, ID, Teton County, ID

The radar

The Pocatello radar (KSFX), 132 km from the middle of the area, began a volume at 17:11 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

Riverton, WY (KRIW), launched 12:00Z, 5.1 hours before the alert went out and 263 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-pSkew-T log-p diagram, Riverton, WY at 12:00Z on 2021-02-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Riverton, WY at 12:00Z on 2021-02-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 74 square meters per square second.1939587897117136Sfc1 km3 km6 km9 kmRMLM
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
1674 m above ground
0-6 km bulk shear
84 kt
0-1 km storm-relative helicity
74 m²/s²
0-3 km storm-relative helicity
129 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

461 
WWUS85 KPIH 201708
SPSPIH

Special Weather Statement
National Weather Service Pocatello ID
1008 AM MST Sat Feb 20 2021
 
IDZ053-054-058-062>066-202000-
Centennial Mountains/Island Park ID-Big Hole Mountains ID-
Upper Snake River Plain ID-Marsh and Arbon Highlands ID-
Teton Valley ID-Caribou Range ID-Blackfoot Mountains ID-
Lower Snake River Plain ID-
1008 AM MST Sat Feb 20 2021

...ENHANCED BAND OF SNOW WORKING THROUGH IDAHO FALLS, REXBURG, AND 
ASHTON ADVANCING TOWARD SWAN VALLEY AND DRIGGS THROUGH NOON... 

At 1002 AM MST, an enhanced band of snow extended from Idaho Falls 
through Ashton and was advancing into the eastern highlands. 
Individuals in Swan Valley and the Teton Valley should be prepared 
for winter weather through noon. Reduced visibility with blowing and 
drifting snow, slick road conditions, and accumulating snowfall are 
anticipated. If you have travel plans that will take you into the 
eastern highlands on Highway 33 or 26, be sure to check road 
conditions before venturing out as temporary road closures are 
possible. 

Locations impacted include...
Idaho Falls, Rexburg, Rigby, Driggs, Ashton, Swan Valley, Felt, Ririe
Reservoir, Goshen, Wayan, Marysville, Lorenzo, Palisades Reservoir,
Blackfoot Reservoir, Ammon, Shelley, Victor, Iona, Sugar City and
Ucon.

LAT...LON 4332 11255 4455 11117 4453 11113 4449 11109
      4413 11109 4412 11105 4268 11104
TIME...MOT...LOC 1702Z 180DEG 0KT 4278 11205 

$$

Huston

Nearby

Special Weather Statements in Idaho, 2021Every special weather statement in 2021

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.