Alert archive / Montana / Lake Wind Advisories in 2021

Lake Wind Advisory 3, NWS Missoula, MT

April 21, 2021Flathead County, Lake County, Sanders County, Montana

NWS Missoula, MT issued this lake wind advisory at Apr 21, 2021, 12:54 PM MDT for Flathead County, Lake County, Sanders County, Montana. It took effect at Apr 22, 2021, 11:00 AM MDT. It was in force for 3 hr.

The area

The counties it named.

The facts

Issued
Apr 21, 2021, 12:54 PM MDT (18:54 UTC)
In effect from
Apr 22, 2021, 11:00 AM MDT
Expired
Apr 22, 2021, 2:01 PM MDT
In force
3 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 18:55 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, 6.9 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 2021-04-21Temperature 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 2021-04-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 25 square meters per square second.1939Sfc1 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
2403 m above ground
0-6 km bulk shear
23 kt
0-1 km storm-relative helicity
25 m²/s²
0-3 km storm-relative helicity
33 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

904 
WWUS75 KMSO 211854
NPWMSO

URGENT - WEATHER MESSAGE
National Weather Service Missoula MT
1254 PM MDT Wed Apr 21 2021

MTZ003-221900-
/O.NEW.KMSO.LW.Y.0003.210422T1500Z-210423T0000Z/
Flathead/Mission Valleys-
1254 PM MDT Wed Apr 21 2021

...LAKE WIND ADVISORY IN EFFECT FROM 9 AM TO 6 PM MDT THURSDAY
FOR FLATHEAD LAKE...

* WHAT...A strong cold front will bring north to east winds of 15
  to 25 mph with gusts 30 to 40 mph developing by late morning and
  continuing into the afternoon. These winds will generate waves
  between 1 to 2 feet.

* WHERE...Flathead Lake.

* WHEN...From 9 AM to 6 PM MDT Thursday.

* 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.

&&

$$
2 follow-up statements
434 
WWUS75 KMSO 221310
NPWMSO

URGENT - WEATHER MESSAGE
National Weather Service Missoula MT
710 AM MDT Thu Apr 22 2021

MTZ003-230000-
/O.EXT.KMSO.LW.Y.0003.210422T1700Z-210423T0000Z/
Flathead/Mission Valleys-
710 AM MDT Thu Apr 22 2021

...LAKE WIND ADVISORY NOW IN EFFECT FROM 11 AM THIS MORNING TO
6 PM MDT THIS EVENING FOR FLATHEAD LAKE...

* WHAT...A strong cold front will bring north to east winds of 15
  to 25 mph with gusts 30 to 40 mph and continuing into the 
  afternoon. These winds will generate waves between 1 to 2 feet.

* WHERE...Flathead Lake.

* WHEN...From 11 AM this morning to 6 PM MDT this evening.

* 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.

&&

$$
106 
WWUS75 KMSO 222001
NPWMSO

URGENT - WEATHER MESSAGE
National Weather Service Missoula MT
201 PM MDT Thu Apr 22 2021

MTZ003-222115-
/O.CAN.KMSO.LW.Y.0003.000000T0000Z-210423T0000Z/
Flathead/Mission Valleys-
201 PM MDT Thu Apr 22 2021

...LAKE WIND ADVISORY IS CANCELLED...

The constant rain has stabilized the atmosphere, therefore
lessening the wind potential. Northerly winds between 10 and 20
mph are still expected over the lake for the remainder of the
afternoon. 

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 21, 12:54 PM MDTWinter Weather AdvisoryMSOFlathead, Lake29 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.