Alert archive / Montana / Lake Wind Advisories in 2021

Lake Wind Advisory 4, NWS Missoula, MT

May 17, 2021Flathead County, Lake County, Sanders County, Montana

NWS Missoula, MT issued this lake wind advisory at May 17, 2021, 2:36 PM MDT for Flathead County, Lake County, Sanders County, Montana. It took effect at May 18, 2021, 3:00 PM MDT. It was in force for 6 hr.

The area

The counties it named.

The facts

Issued
May 17, 2021, 2:36 PM MDT (20:36 UTC)
In effect from
May 18, 2021, 3:00 PM MDT
Expired
May 18, 2021, 9:00 PM MDT
In force
6 hr
Issued by
NWS Missoula, MT

Counties Flathead County, MT, Lake County, MT, Sanders County, MT

The radar

The Missoula radar (KMSX), 98 km from the middle of the area, began a volume at 20:38 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 12:00Z, 8.6 hours before the alert went out and 149 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 2021-05-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 29 joules per kilogram.LCLLFCEL10008507005003002001001 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 2021-05-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 90 square meters per square second.193958Sfc1 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
29 J/kg
Mixed-layer CIN
-894 J/kg
Mixed-layer LCL
2689 m above ground
0-6 km bulk shear
27 kt
0-1 km storm-relative helicity
90 m²/s²
0-3 km storm-relative helicity
78 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

417 
WWUS75 KMSO 172036
NPWMSO

URGENT - WEATHER MESSAGE
National Weather Service Missoula MT
236 PM MDT Mon May 17 2021

MTZ003-182045-
/O.NEW.KMSO.LW.Y.0004.210518T2100Z-210519T0300Z/
Flathead/Mission Valleys-
236 PM MDT Mon May 17 2021

...LAKE WIND ADVISORY IN EFFECT FROM 3 PM TO 9 PM MDT TUESDAY FOR
FLATHEAD LAKE...

* WHAT...Waves 1 to 3 feet with west winds 20 to 25 mph with 
  gusts up to 35 mph expected on Flathead Lake.

* WHERE...Flathead/Mission Valleys.

* WHEN...From 3 PM to 9 PM MDT Tuesday.

* IMPACTS...Strong winds and rough waves will create hazardous 
  conditions for small craft.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Boaters on area lakes should use extra caution since strong winds
and rough waves can overturn small craft.

&&

$$
1 follow-up statement
791 
WWUS75 KMSO 190246
NPWMSO

URGENT - WEATHER MESSAGE
National Weather Service Missoula MT
846 PM MDT Tue May 18 2021

MTZ003-190400-
/O.EXP.KMSO.LW.Y.0004.000000T0000Z-210519T0300Z/
Flathead/Mission Valleys-
846 PM MDT Tue May 18 2021

...LAKE WIND ADVISORY WILL EXPIRE AT 9 PM MDT THIS EVENING FOR
FLATHEAD LAKE...



$$

The office that day

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

IssuedProductOfficeCountiesLasted
May 17, 2:40 PM MDTWinter Storm WatchMSOFlathead, Lake24 hr

Nearby

Lake Wind Advisories in Montana, 2021Every lake wind advisory 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.