Alert archive / Idaho / Special Weather Statements in 2016

Special Weather Statement, NWS Missoula, MT

May 21, 2016Lewis County, Idaho

NWS Missoula, MT issued this special weather statement at May 21, 2016, 5:36 PM PDT for Lewis County, Idaho. It was in force for 24 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 21, 2016, 5:36 PM PDT (00:36 UTC)
Expired
May 21, 2016, 6:00 PM PDT
In force
24 min
Issued by
NWS Missoula, MT

County Lewis County, ID

The radar

The Missoula radar (KMSX), 198 km from the middle of the area, began a volume at 00:36 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

Spokane, WA (KOTX), launched 00:00Z, 0.6 hours before the alert went out and 196 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, Spokane, WA at 00:00Z on 2016-05-22Temperature 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 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Spokane, WA at 00:00Z on 2016-05-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 34 square meters per square second.1939587897Sfc1 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
815 m above ground
0-6 km bulk shear
9 kt
0-1 km storm-relative helicity
34 m²/s²
0-3 km storm-relative helicity
151 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

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What forecasters said that day

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

NWS Missoula, MT wrote its last area forecast discussion before this special weather statement went out at May 21, 1:11 PM PDT, 4 hours 25 minutes earlier.

Area forecast discussion, May 21, 1:11 PM PDT, 4 hours 25 minutes before
Area Forecast Discussion
National Weather Service Missoula MT
211 PM MDT SAT MAY 21 2016

...SNOW ABOVE 5500 FEET IN NORTHWEST MONTANA TONIGHT-MONDAY...

.DISCUSSION...Rain continues to expand into the region from the
south with a broad low pressure system just to the west. This low
pressure system is forecast to move northeast during today and
tonight which will cause precipitation to decrease south of I-90
and Highway 12 this evening and overnight, while high chances for
rain will remain in northwest Montana. Snow levels are also
expected to lower with this weather system so accumulations are
looking more likely above around 6000 feet. Snow accumulations in
the Glacier region, above 6000 feet could range between 1-2 feet
for Sunday through Monday. Winds are also expected to increase
through Sunday with valley locations to see wind gusts 25-35 mph,
while the high terrain will see winds 35-50 mph with higher gusts.

The closed low in southern Alberta will continue to bring wrap
around moisture to Northwest Montana Monday and Tuesday. It may
seem ominous with the main impact snow in the higher elevations along
the continental divide and Glacier NP. Outdoor activities may be
limited above 6000 feet due to the snowy and raw conditions.

Otherwise from midweek through Memorial weekend continues to look
wet with afternoon/evening scattered showers and perhaps a
thunderstorm. A more organized system may bring a better chance
for widespread precipitation next weekend. Expect temperatures to
recover to near normal readings by mid to late next week. Normal
highs by then are in the low 70s.

&&

.AVIATION...Showers and isolated thunderstorms continue to expand
through north central and western Montana this afternoon in
association with a low pressure systems centered in Oregon.
Specific locations of any thunderstorms will be tough to
determine due to their isolated nature this afternoon. Model
guidance agree that precipitation will focus through northwest
Montana by late this evening so low clouds and rain will be
common. Some clearing south of I-90 and Highway 12 may lead to
morning fog. Snow levels will also lower tonight to around
5500-6000 feet with high elevation snow accumulations through
Monday. Winds will also become westerly and gusty on Sunday as
the low moves northward into southern Alberta.

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...Winter Weather Advisory from midnight tonight to noon MDT Monday
     ABOVE 5500 FEET for the West Glacier Region.

ID...None.
&&

In the hours before

Special weather statement, May 21, 5:15 PM PDT, 21 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MISSOULA MT
615 PM MDT SAT MAY 21 2016

MTZ007-220045-
BUTTE/BLACKFOOT REGION MT-
615 PM MDT SAT MAY 21 2016

...SIGNIFICANT WEATHER ADVISORY FOR SOUTH CENTRAL POWELL COUNTY UNTIL
645 PM MDT...

AT 615 PM MDT...DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM NEAR
DEER LODGE...MOVING NORTHEAST AT 20 MPH.

HALF INCH HAIL AND WINDS IN EXCESS OF 30 MPH WILL BE POSSIBLE WITH
THIS STORM.

LOCATIONS IMPACTED INCLUDE...
DEER LODGE.

LAT...LON 4628 11283 4638 11290 4656 11260 4638 11246
TIME...MOT...LOC 0015Z 236DEG 15KT 4637 11278
Special weather statement, May 21, 5:36 PM PDT, 0 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MISSOULA MT
536 PM PDT SAT MAY 21 2016

IDZ006-007-220100-
SOUTHERN CLEARWATER MOUNTAINS ID-OROFINO/GRANGEVILLE REGION ID-
536 PM PDT SAT MAY 21 2016

...SIGNIFICANT WEATHER ADVISORY FOR CENTRAL IDAHO COUNTY UNTIL 600 PM
PDT...

AT 536 PM PDT...DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM NEAR
GRANGEVILLE...MOVING NORTH AT 15 MPH.

PEA SIZE HAIL AND WINDS IN EXCESS OF 30 MPH WILL BE POSSIBLE WITH
THIS STORM.

LOCATIONS IMPACTED INCLUDE...
GRANGEVILLE...STITES AND HARPSTER.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

FREQUENT CLOUD TO GROUND LIGHTNING IS OCCURRING WITH THIS STORM.
LIGHTNING CAN STRIKE 10 MILES AWAY FROM A THUNDERSTORM. SEEK A SAFE
SHELTER INSIDE A BUILDING OR VEHICLE.

&&

LAT...LON 4587 11595 4586 11615 4609 11621 4610 11590
TIME...MOT...LOC 0036Z 185DEG 12KT 4592 11604

The office that day

Everything else NWS Missoula, MT issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 21, 5:15 PM PDTSpecial Weather StatementMSODeer Lodge30 min
May 21, 5:52 PM PDTSpecial Weather StatementMSOPowell23 min
May 21, 6:49 PM PDTSpecial Weather StatementMSO26 min
May 22, 3:08 AM PDTLake Wind AdvisoryMSOFlathead, Lake, Sanders17 hr
May 21, 7:33 PM PDTSpecial Weather StatementMSOLewis42 min

Nearby

Special Weather Statements in Idaho, 2016Every special weather statement in 2016

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.