Alert archive / Montana / Winter Storm Warnings in 2018

Winter Storm Warning 13, NWS Missoula, MT

October 1, 2018Flathead County, Lake County, Montana

NWS Missoula, MT issued this winter storm warning at Oct 1, 2018, 2:49 PM MDT for Flathead County, Lake County, Montana. It took effect at Oct 2, 2018, 3:00 AM MDT. It was in force for 30 hr. 2 reports came from inside the area while it was in force.

The area

The counties it named, with what was reported inside it.

The facts

Issued
Oct 1, 2018, 2:49 PM MDT (20:49 UTC)
In effect from
Oct 2, 2018, 3:00 AM MDT
Expired
Oct 3, 2018, 8:59 AM MDT
In force
30 hr
Issued by
NWS Missoula, MT

Counties Flathead County, MT, Lake County, MT

The radar

The Missoula radar (KMSX), 104 km from the middle of the area, began a volume at 20:53 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

TimeReportWhereRemark
Oct 2, 1:00 PM MDTSNOW 65 Ene Blacktail, MTSNOW BEGAN BETWEEN 5-6 AM MDT.
Oct 3, 8:00 AM MDTSNOW 1.59 Wnw Apgar, MTBIG CREEK ALONG THE NORTH FORK ROAD.

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

The nearest sounding before it

Spokane, WA (KOTX), launched 12:00Z, 8.8 hours before the alert went out and 177 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 12:00Z on 2018-10-01Temperature 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°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Spokane, WA at 12:00Z on 2018-10-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 180 square meters per square second.19395878Sfc1 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
1475 m above ground
0-6 km bulk shear
50 kt
0-1 km storm-relative helicity
180 m²/s²
0-3 km storm-relative helicity
243 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

920 
WWUS45 KMSO 012049
WSWMSO

URGENT - WINTER WEATHER MESSAGE
National Weather Service Missoula MT
249 PM MDT Mon Oct 1 2018

MTZ002-031100-
/O.NEW.KMSO.WS.W.0013.181002T0900Z-181003T1800Z/
West Glacier Region-
249 PM MDT Mon Oct 1 2018

...WINTER STORM WARNING IN EFFECT FROM 3 AM TUESDAY TO NOON MDT
WEDNESDAY ABOVE 5000 FEET...

* WHAT...Heavy snow expected. Total snow accumulations below 4000
  feet 1 to 3 inches, above 5000 feet 5 to 8 inches, with
  localized amounts up to 18-22 inches above 6500 feet, are 
  expected.

* WHERE...West Glacier Region.

* WHEN...From 3 AM Tuesday to noon MDT Wednesday.

* ADDITIONAL DETAILS...Plan on difficult travel conditions. Be 
  prepared for significant reductions in visibility at times.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Storm Warning for snow means severe winter weather
conditions will make travel very hazardous or impossible. If you
must travel, keep an extra flashlight, food and water in your
vehicle in case of an emergency. The latest road conditions for
the state you are calling from can be obtained by calling 5 1 1.

&&

$$
2 follow-up statements
344 
WWUS45 KMSO 022033
WSWMSO

URGENT - WINTER WEATHER MESSAGE
National Weather Service Missoula MT
233 PM MDT Tue Oct 2 2018

MTZ002-031800-
/O.CON.KMSO.WS.W.0013.000000T0000Z-181003T1800Z/
West Glacier Region-
233 PM MDT Tue Oct 2 2018

...WINTER STORM WARNING REMAINS IN EFFECT UNTIL NOON MDT
WEDNESDAY ABOVE 4000 FEET...

* WHAT...Heavy snow above 4000 feet. Total snow accumulations
  below 4000: feet 1 to 3 inches, above 5000 feet: around 6 inches
  has already fallen, with an additional 4 to 7 inches expected by
  early morning. Localized amounts up to 18-22 inches above 6500
  feet are expected.

* WHERE...West Glacier Region including Marias Pass.

* WHEN...Until noon MDT Wednesday.

* ADDITIONAL DETAILS...Travel could be very difficult. Gusty winds
  could bring down tree branches and create very low visibilities.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Storm Warning for snow means severe winter weather
conditions will make travel very hazardous or impossible. If you
must travel, keep an extra flashlight, food and water in your
vehicle in case of an emergency. 

The latest road conditions for the state you are calling from can
be obtained by calling 5 1 1.

&&

$$
797 
WWUS45 KMSO 031459
WSWMSO

URGENT - WINTER WEATHER MESSAGE
National Weather Service Missoula MT
859 AM MDT Wed Oct 3 2018

MTZ002-031600-
/O.CAN.KMSO.WS.W.0013.000000T0000Z-181003T1800Z/
West Glacier Region-
859 AM MDT Wed Oct 3 2018

...WINTER STORM WARNING IS CANCELLED...

Higher elevations of Glacier National Park could pick up an 
additional half to one inch of snow. Generally across the area 
however there will be no further accumulation. 

$$

Nearby

Winter Storm Warnings in Montana, 2018Every winter storm 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.