Alert archive / Idaho / Severe Thunderstorm Warnings in 2018

Severe Thunderstorm Warning 47, NWS Pocatello, ID

June 21, 2018Fremont County, Idaho

NWS Pocatello, ID issued this severe thunderstorm warning at Jun 21, 2018, 3:49 PM MDT for Fremont County, Idaho. It was in force for 15 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Jun 21, 2018, 3:49 PM MDT (21:49 UTC)
Expired: Jun 21, 2018, 4:04 PM MDT
In force: 15 min
Issued by: NWS Pocatello, ID
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

County Fremont County, ID

The radar

The Pocatello radar (KSFX), 158 km from the middle of the area, began a volume at 21:49 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, 9.8 hours before the alert went out and 279 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: 1457 m above ground
0-6 km bulk shear: 42 kt
0-1 km storm-relative helicity: -22 m²/s²
0-3 km storm-relative helicity: 59 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Pocatello, ID wrote its last area forecast discussion before this severe thunderstorm warning went out at Jun 21, 1:08 PM MDT, 2 hours 41 minutes earlier.

Area forecast discussion, Jun 21, 1:08 PM MDT, 2 hours 41 minutes before

Area Forecast Discussion
National Weather Service Pocatello ID
108 PM MDT Thu Jun 21 2018

.DISCUSSION...A fairly vigorous disturbance moving from Northern
Idaho to Montana this afternoon/evening with thunderstorms expected
as far south as Idaho Falls. These storms could produce some hail
and strong gusty winds, and may be marginally severe near the
Idaho/Montana line. Isolated showers and thunderstorms will ling i
the Upper Snake Highlands around Driggs and Island Park on Friday,
otherwise high pressure and mostly sunny skies builds in from the
west. A disturbance on Saturday will drop further south into this
area, bringing scattered showers to the central mountains and
eastern highlands. Temperatures will be about 5 degrees cooler and
winds in the Snake Plain on the breezy side. Expect this
disturbance will move slowly east on Sunday, leaving a chance of
showers in the eastern highlands. Monday through Wednesday look
pretty dry, but the storm track is not very far north of here and
there is room for another passing disturbance to affect this area. RS

&&

.AVIATION...Main focus today will be on winds at the Snake Plain
terminals due to a cold front. Thunder will also be a threat across
the northern portion of the forecast area. KDIJ is best positioned
to see some isolated thunderstorms this afternoon, so have included
VCTS. Would not rule out seeing some outflows at KIDA and KPIH, but
gradient west/southwest winds will prevail. Another wave coming out
of western Montana tomorrow morning will bring showers mainly over
our eastern terminals: KIDA and KDIJ. MET Guidance suggests KDIJ may
dip to MVFR briefly tomorrow morning. Just keeping a scattered deck
at 2000 ft for now.  Hinsberger

&&

.FIRE WEATHER...A cold front passed through the area today. Breezy
conditions will continue into the evening. Thunderstorms will also
continue across Lemhi County and the Island Park area. Outflows from
these storms may extend to Idaho Falls this evening, but should be
mitigated by gradient winds. A short wave will help trigger more
thunderstorms tomorrow afternoon over the Eastern Highlands while
the rest of the area will be a bit less breezy than today. We should
see another cold front advance into the area on Saturday morning.
This will bring another round of strong winds to the area as well as
some isolated thunderstorms. Things look to be a bit drier on
Sunday, though some showers/isolated thunderstorms may pop up near
the Wyoming border. On Tuesday morning, another cold front pushes
through, but models are keeping this fairly dry except for northern
Lemhi county. This front will also bring breezy conditions to the
Snake Plain. Hinsberger

&&

.HYDROLOGY...Waters continue to recede on local rivers. The Snake
River near Menan remains above flood stage, but may fall below
that level in a few hours. A Flood Advisory also remains in effect
for the Snake River at Blackfoot. Even as waters recede, slippery
muddy banks and debris continue to pose a hazard for anyone
venturing close to the rivers. RS

&&

.PIH WATCHES/WARNINGS/ADVISORIES...None.

&&

In the hours before

Local storm report, Jun 21, 2:30 PM MDT, 1 hour 19 minutes before

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Local storm report, Jun 21, 2:40 PM MDT, 1 hour 9 minutes before

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Local storm report, Jun 21, 2:59 PM MDT, 50 minutes before

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Special weather statement, Jun 21, 3:25 PM MDT, 24 minutes before

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Local storm report, Jun 21, 3:41 PM MDT, 8 minutes before

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Special weather statement, Jun 21, 3:41 PM MDT, 8 minutes before

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The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 21, 1:13 PM MDT	Special Weather Statement	PIH	Butte	32 min
Jun 21, 1:24 PM MDT	Severe Thunderstorm Warning	PIH	Butte, Custer	51 min
Jun 21, 2:28 PM MDT	Special Weather Statement	PIH	Clark	47 min
Jun 21, 3:25 PM MDT	Special Weather Statement	PIH	Fremont	35 min
Jun 21, 3:41 PM MDT	Special Weather Statement	PIH	Fremont	49 min

Nearby

Severe Thunderstorm Warnings in Idaho, 2018 Every severe thunderstorm 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.