Special Weather Statement, NWS Missoula, MT

Area Forecast Discussion
National Weather Service Missoula MT
400 AM MDT FRI AUG 14 2015

...Potential for Strong to Severe Thunderstorms Today...

.DISCUSSION...A weak disturbance moving northward out of southern
Idaho will cause scattered showers and isolated thunderstorms this
morning. The path of the storms will be across north central Idaho
into west central Montana. These storms will be capable of gusty
and erratic winds, plus a brief period of moderate rain under the
storm cores. This feature is anticipated to exit the region by mid
to late morning.

This afternoon the atmosphere still appears to become fairly
unstable to support the development of widespread thunderstorms
with the potential of a few becoming severe. The location of
greatest threat of strong to severe storms will be east of the
Montana/Idaho border. The severe storms will be capable of
producing damaging winds, large hail and periods of heavy rain. As
a cold front approaches the region, the threat of strong storms
will move to the east through the afternoon and evening.

The approaching cold front is anticipated to cause southerly winds
to steadily increase throughout the afternoon. The front appears
to move into north central Idaho by late afternoon/early evening,
then continue to push through the Northern Rockies throughout the
night. The winds will quickly switch to a westerly component with
widespread gusts potentially reaching speeds of 30 to 40 mph
during the frontal passage.

Saturday will be a much cooler day, with temperatures as much as
20 degrees cooler than Friday, placing many valley locations in
mid 70s to lower 80s. Showers and isolated thunderstorms are
expected across far northwest Montana near the Canadian border,
however areas generally south of Kalispell will remain dry. Winds
will remain breezy Saturday morning, especially across northwest
Montana, but will gradually decrease through the day.

Sunday and Monday will see gradual warming, though temperatures
will not return to nearly the warmth we've seen this week.
Forecast models continue to struggle with the timing of another
trough of low pressure moving through the region, however it looks
like passage will occur roughly in the late Monday to Tuesday time
frame. When this occurs, temperatures will cool again with the
potential for a period of showers. Beyond Tuesday, a seasonal
weather pattern is expected with near normal temperatures and low
chances of precipitation.

&&

.AVIATION....Smoke from area wildfires may locally lower
visibility and obscure the higher terrain today, particularly
across north central Idaho. A wave of energy moving into central
Idaho this morning will allow for the formation of showers and
thunderstorms this morning. KSMN, KMSO and KBTM may all see a
brief period of light rain, gusty winds and lightning this
morning. This initial wave will exit the region by late morning,
but the lull will not last long as instability and lift ahead of
an approaching cold front will allow for thunderstorm development
this afternoon. The strongest storms are expected in western
Montana, potentially impacting KGPI, KMSO and KBTM. Storms this
afternoon will be capable of gusty and erratic winds, possibly up
to 55 kts with the strongest storms, hail, and brief heavy rain
which could significantly lower visibility at times. Another
concern with aviation today will be increasing winds ahead of and
behind the cold front. Cold frontal passage is expected through
Idaho during the late afternoon, and through Montana in the
evening. Gusty southwest winds will give way to west winds behind
the cold front, with potential gusts up to 40kts, especially near
ridge tops.

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...RED FLAG WARNING from Noon today to Midnight MDT tonight
     Bitterroot...East Lolo...Flathead/Glacier Park...Kootenai...
     Salish and Kootenai Reservation...West Lolo.

ID...RED FLAG WARNING from 11 AM this morning to 11 PM PDT this
     evening Clearwater/Nez perce...Palouse/Hells Canyon.

&&

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MISSOULA MT
106 PM MDT FRI AUG 14 2015

MTZ001-004-141930-
KOOTENAI/CABINET REGION MT-LOWER CLARK FORK REGION MT-
106 PM MDT FRI AUG 14 2015

...SIGNIFICANT WEATHER ADVISORY FOR CENTRAL SANDERS AND SOUTHWESTERN
FLATHEAD COUNTIES UNTIL 130 PM MDT...

AT 105 PM MDT...DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM 11
MILES EAST OF THOMPSON FALLS...MOVING NORTHEAST AT 40 MPH.

HALF INCH HAIL AND WINDS IN EXCESS OF 40 MPH WILL BE POSSIBLE WITH
THIS STORM.

LOCATIONS IMPACTED INCLUDE...
SNIDER...EDDY AND BEND.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

FREQUENT CLOUD TO GROUND LIGHTNING IS OCCURRING WITH THIS STORM.
LIGHTNING CAN STRIKE 15 MILES AWAY FROM A THUNDERSTORM. SEEK A SAFE
SHELTER INSIDE A BUILDING OR VEHICLE.

&&

LAT...LON 4782 11474 4752 11506 4761 11528 4796 11510
TIME...MOT...LOC 1905Z 212DEG 34KT 4764 11510

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MISSOULA MT
117 PM PDT FRI AUG 14 2015

IDZ005-006-142045-
SOUTHERN CLEARWATER MOUNTAINS ID-NORTHERN CLEARWATER MOUNTAINS ID-
117 PM PDT FRI AUG 14 2015

...SIGNIFICANT WEATHER ADVISORY FOR NORTH CENTRAL IDAHO AND CENTRAL
CLEARWATER COUNTIES UNTIL 145 PM PDT...

AT 117 PM PDT...DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM 11
MILES EAST OF LOWELL...OR 31 MILES EAST OF KAMIAH...MOVING NORTH AT
40 MPH.

DIME SIZE HAIL AND WIND GUSTS UP TO 50 MPH WILL BE POSSIBLE WITH THIS
STORM.

THIS STORM WILL REMAIN OVER MAINLY RURAL AREAS OF NORTH CENTRAL IDAHO
AND CENTRAL CLEARWATER COUNTIES.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

FREQUENT CLOUD TO GROUND LIGHTNING IS OCCURRING WITH THIS STORM.
LIGHTNING CAN STRIKE 15 MILES AWAY FROM A THUNDERSTORM. SEEK A SAFE
SHELTER INSIDE A BUILDING OR VEHICLE.

&&

LAT...LON 4598 11517 4610 11549 4663 11548 4643 11485
TIME...MOT...LOC 2017Z 193DEG 36KT 4620 11536