Special Weather Statement, NWS Missoula, MT

Area Forecast Discussion
National Weather Service Missoula MT
359 AM MDT Sat Aug 6 2016

.DISCUSSION...A plume of moisture continues to stream into the
Northern Rockies this morning causing scattered to numerous
high based convection, especially over north central Idaho and
northwest Montana. An isolated thunderstorm will be embedded
within this band of convection this morning. This plume will
slowly move off to the east throughout the day, but afternoon
instability could allow for the development of strong
thunderstorms across western Montana. The best instability appears
to be over southwest Montana, especially the Butte/Anaconda area.
These storms will be capable of producing gusty winds, small hail
and moderate to heavy rain. The convection should diminish during
the overnight hours.

A more significant disturbance will track across the Northern
Rockies on Sunday and interact with a considerable amount of
atmosphere moisture. Most locations across the region should
receive a decent amount of rain. The afternoon/evening instability
could allow for the development of strong to potentially severe
thunderstorms. Any hefty convection that does develop could
produce heavy rainfall rates, creating hydrological concerns. The
exact track of the heaviest precipitation is a little uncertain,
but general consensus will be across southern Idaho county into
Butte/Anaconda area then up along the Continental Divide to
Glacier Park.

Monday through Wednesday, an upper level low will slowly move
through the Northern Rockies leading to a decent chance of showers
and thunderstorms, especially across Northwest Montana. Daytime
temperatures will be 5-10 degrees below normal with highs in the
70s for many valley locations. The upper low is expected to depart
by late next week which will allow for considerable warming and
drying.

&&

.AVIATION...Monsoonal moisture will continue to track across the
Northern Rockies today. A plume of numerous showers with embedded
thunderstorms is currently tracking across north central Idaho up
into northwest Montana. KGPI and KMSO will be impacted by high
based convection throughout the day. The moisture will shift to
the east throughout day. As the atmosphere destabilizes this
afternoon, expect the convection to become stronger in nature.
Thunderstorms this afternoon and evening could produce gusty and
erratic winds, small hail and moderate to heavy rainfall. The
strongest storms will be across northwest and southwest Montana
with the biggest impact being at KGPI and KBTM. The convection is
anticipated to diminish after sunset tonight.

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...Fire Weather Watch from 3 PM MDT this afternoon through this
     evening Deerlodge/West Beaverhead...East Beaverhead.

ID...&&

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MISSOULA MT
211 PM MDT SAT AUG 6 2016

IDZ006-009-010-MTZ005>007-062100-
EASTERN LEMHI COUNTY ID-SOUTHERN CLEARWATER MOUNTAINS ID-
WESTERN LEMHI COUNTY ID-MISSOULA/BITTERROOT VALLEYS MT-
BITTERROOT/SAPPHIRE MOUNTAINS MT-BUTTE/BLACKFOOT REGION MT-
211 PM MDT SAT AUG 6 2016

...SIGNIFICANT WEATHER ADVISORY FOR EAST CENTRAL IDAHO...NORTHERN
LEMHI...WEST CENTRAL DEER LODGE...CENTRAL RAVALLI AND SOUTHWESTERN
GRANITE COUNTIES UNTIL 300 PM MDT/200 PM PDT/...

AT 210 PM MDT/110 PM PDT/...DOPPLER RADAR WAS TRACKING STRONG
THUNDERSTORMS ALONG A LINE EXTENDING FROM 20 MILES SOUTHWEST OF DARBY
TO NEAR GIBBONSVILLE. MOVEMENT WAS NORTHEAST AT 30 MPH.

PEA SIZE HAIL AND WIND GUSTS UP TO 50 MPH WILL BE POSSIBLE WITH THESE
STORMS.

LOCATIONS IMPACTED INCLUDE...
HAMILTON...DARBY...CONNER...LOST TRAIL PASS...SULA...CHARLOS
HEIGHTS...COMO AND GRANTSDALE.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

FREQUENT CLOUD TO GROUND LIGHTNING IS OCCURRING WITH THESE STORMS.
LIGHTNING CAN STRIKE 10 MILES AWAY FROM A THUNDERSTORM. SEEK A SAFE
SHELTER INSIDE A BUILDING OR VEHICLE.

&&

LAT...LON 4589 11347 4594 11351 4587 11354 4587 11358
      4584 11362 4584 11370 4575 11382 4575 11385
      4578 11387 4576 11390 4570 11391 4568 11394
      4564 11390 4562 11390 4561 11384 4557 11389
      4587 11464 4632 11432 4596 11338
TIME...MOT...LOC 2010Z 217DEG 25KT 4589 11456 4562 11391