Lake Wind Advisory 3, NWS Missoula, MT

030 
WWUS75 KMSO 050937
NPWMSO

URGENT - WEATHER MESSAGE
National Weather Service Missoula MT
337 AM MDT Sat Aug 5 2017

MTZ003-051500-
/O.CON.KMSO.LW.Y.0003.000000T0000Z-170805T1500Z/
Flathead/Mission Valleys-
337 AM MDT Sat Aug 5 2017

...LAKE WIND ADVISORY REMAINS IN EFFECT UNTIL 9 AM MDT THIS
MORNING FOR FLATHEAD LAKE...

The National Weather Service in Missoula has issued a Lake Wind
Advisory for Flathead Lake...which is in effect until 9 AM MDT
Saturday.

* Impacts/Timing: Gusty north and east winds continue due to a
  strong cold front, bringing choppy lake conditions particularly
  to the west and south portions of the lake. Turbulent conditions
  are forecast to persist through the morning as winds slowly
  subside.

* Winds: North and east sustained at 12 to 20 mph with gusts to 
  35 mph.
 
* Wave heights: Two to three foot waves are expected over open
  water over the middle of Flathead Lake and across the south and
  west shores, persisting through the morning. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Lake Wind Advisory indicates that winds will cause rough chop
on area lakes. Small boats will be especially prone to capsizing.

Note...The experimental wave height forecasts are representative
of the mid lake waters and downwind shores. Wave heights may be
significantly less on upwind shores.

&&

$$

588 
WWUS75 KMSO 051431
NPWMSO

URGENT - WEATHER MESSAGE
National Weather Service Missoula MT
831 AM MDT Sat Aug 5 2017

MTZ003-051545-
/O.EXP.KMSO.LW.Y.0003.000000T0000Z-170805T1500Z/
Flathead/Mission Valleys-
831 AM MDT Sat Aug 5 2017

...LAKE WIND ADVISORY WILL EXPIRE AT 9 AM MDT THIS MORNING FOR
FLATHEAD LAKE...


$$

Area Forecast Discussion
National Weather Service Missoula MT
218 PM MDT Fri Aug 4 2017

.DISCUSSION...An unstable atmosphere is developing over north
central Idaho and western Montana late this afternoon, and should
temporarily further help mix out some of the valley smoke. The
atmosphere is becoming moist and unstable enough over western
Montana, mainly north and east of Missoula, to support a few late
afternoon showers but very little precipitation.

A weather disturbance and cold front will cross the Continental
Divide westward and shift south across western Montana this
evening, causing increasing winds. Significant waves are expected
to develop on larger lakes, such as Flathead Lake, into the
evening. This cold front and upper level weather disturbance will
also further moisten the atmosphere, mainly over northwest
Montana (again, mainly north and east of Missoula) and support a
few showers through much of the night.

This same weather disturbance will linger over mainly
southwest Montana on Saturday, with isolated afternoon showers or
even a thunderstorm possible south and east of Missoula to the
Continental Divide.

North Central Idaho and Lemhi County, ID will remain largely
unaffected by the cold front and weather disturbance, so status
quo is generally expected through Saturday.

High pressure will return Sunday into Monday with near normal
temperatures and dry conditions. However, this will also mean that
area fires will again cause an increase in smoke settling into
valleys across the Northern Rockies.

High pressure will generally be the controlling influence into
next week with near normal temperatures. The difference being
that a northwest flow aloft may again direct weak weather
disturbances southeastward across mainly western Montana and
possibly support isolated afternoon and evening showers and
thunderstorms.

&&

.AVIATION...
Starting this afternoon, a Canadian cold front will bring
increasing north winds to area terminals, especially KGPI and
KMSO. Behind the front, the winds will shift to a more easterly
direction overnight. Ahead of this front, a few showers and
isolated thunderstorms will be possible in the late afternoon and
evening, mainly along the Continental Divide and north and east
of KMSO. Winds are expected to start increasing around 05/0000Z
at KGPI, and around 05/0600Z for KMSO. Gusty winds of 20-25 kts
will be associated with this cold front.

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...None.
ID...None.
&&