Winter Storm Warning 4, NWS Missoula, MT

102 
WWUS45 KMSO 150307
WSWMSO

URGENT - WINTER WEATHER MESSAGE
NATIONAL WEATHER SERVICE MISSOULA MT
907 PM MDT TUE APR 14 2015


MTZ007-151500-
/O.EXP.KMSO.WS.W.0004.000000T0000Z-150415T0300Z/
/O.CON.KMSO.WW.Y.0029.000000T0000Z-150415T1500Z/
BUTTE/BLACKFOOT REGION-
907 PM MDT TUE APR 14 2015

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 9 AM MDT
WEDNESDAY...
...WINTER STORM WARNING HAS EXPIRED...

THE WINTER STORM WARNING IS NO LONGER IN EFFECT. A WINTER WEATHER
ADVISORY REMAINS IN EFFECT UNTIL 9 AM MDT WEDNESDAY. 

* IMPACTS/TIMING: MINOR SNOW ACCUMULATIONS AND SLICK ROADS WILL
  PERSIST AND CREATE DIFFICULT DRIVING AT TIMES.

* SNOW ACCUMULATIONS: 1-3 INCHES.

* LOCATIONS IMPACTED INCLUDE...BUTTE...GEORGETOWN LAKE...HIGHWAY
  12 GARRISON TO ELLISTON...HOMESTAKE PASS...MACDONALD PASS

&&


$$

IDZ010-MTZ006-151500-
/O.CON.KMSO.WW.Y.0029.000000T0000Z-150415T1500Z/
EASTERN LEMHI COUNTY-BITTERROOT/SAPPHIRE MOUNTAINS-
907 PM MDT TUE APR 14 2015

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 9 AM MDT
WEDNESDAY...

A WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 9 AM MDT
WEDNESDAY. 

* IMPACTS/TIMING: SNOW WILL BE POSSIBLE IN ALL AREAS THROUGH THIS
  EVENING...INCLUDING SALMON. CONDITIONS OVER MOUNTAIN PASSES AND
  THROUGHOUT THE HIGHER TERRAIN...INCLUDING GEORGETOWN LAKE...
  WILL CONTINUE TO BE POOR INTO THE EVENING AND LIKELY REMAIN
  CHALLENGING IN PERSISTENT SHOWERY CONDITIONS OVERNIGHT.

* SNOW ACCUMULATIONS: UP TO 2 INCHES OF SLUSHY SNOW ARE LIKELY 
  ACROSS THE LOWER ELEVATIONS...INCLUDING BUTTE AND SALMON. 
  HIGHER ELEVATION LOCATIONS...INCLUDING MOUNTAIN PASSES AND THE 
  GEORGETOWN LAKE AREA...SHOULD PREPARE FOR AN ADDITIONAL 1- 2 
  INCHES ACCUMULATION THROUGH WEDNESDAY MORNING. 

* LOCATIONS IMPACTED INCLUDE...BANNOCK PASS...HIGHWAY 28 TENDOY 
  TO LONE PINE...HIGHWAY 93 LOST TRAIL PASS TO GIBBONSVILLE...
  LEMHI PASS...SALMON...HIGHWAY 93 SULA TO LOST TRAIL PASS...
  LOLO PASS

$$

Area Forecast Discussion...UPDATED
National Weather Service Missoula MT
403 PM MDT TUE APR 14 2015

.UPDATE...Issued a winter storm warning for Interstate 90
crossing Homestake Pass in Silver Bow county, Montana.

&&

.DISCUSSION...Web cams and observations from around the Butte area
show inclement, snowy, windy conditions...hazardous for those
traveling over Homestake Pass, at least for the next several hours
this evening. Therefore, a winter storm warning has been issued
for I-90 over Homestake Pass.

&&

.AVIATION...The cold Pacific trough will continue to track across
the Northern Rockies tonight through Wednesday morning. Expect
numerous snow showers(with ceiling and visibility reductions) and
gusty northerly winds from Lemhi County to southwest Montana
including KBTM and along the Continental Divide during this
period. A period of heavy snow with visibility less than one half
mile is expected across Silver Bow & Deer Lodge Counties
including KBTM between through around 14/2300z. An upper level
ridge will begin to build in from the northwest bringing drier and
more stable conditions with it during the day on Wednesday and
Thursday. Patchy fog is possible in the Flathead Valley Wednesday
morning. Noble

&&

.PREV DISCUSSION... /ISSUED 310 PM MDT TUE APR 14 2015/

DISCUSSION...An area of enhanced precipitation will continue to
impact much of southwest Montana and parts of eastern Lemhi County
through the rest of this afternoon and into the evening hours.
The heaviest snowfall at present extends from the Sapphire
Mountains east towards the Continental Divide. Icy, snow covered
conditions are already present on Montana Highway 1 at Georgetown
Lake as well as over MacDonald and Homestake Passes. And
challenging travel over these higher elevation locations is likely
to continue into at least this evening. Meanwhile Butte and other
lower elevation locations can also expect to see conditions worsen
as we move towards the evening commute. Although snow may be
initially resistant to accumulate on many roadways, the
anticipated increase in intensity of the next few hours should
lead to at least some slushy spots which may prove dangerous to
commuters. As such Winter Weather Advisories remain in effect
through tonight. The rate of precipitation should start to
diminish after 6 or 7pm MDT, but snow showers will continue
throughout the night which may lead to challenging roadways into
the morning commute.

Showers will diminish across western Montana tomorrow morning,
with partial clearing by the afternoon across the Northern
Rockies. Some patchy morning fog is possible over northwest
Montana, mostly in areas that received precipitation today.

Thursday will see a cool start to the day as skies clear and winds
become calm overnight. A few locations in northwest Montana may
see patchy fog again. Some valley locations, particularly the
Bitterroot Valley, could see temperatures approaching 20 degrees.
Not expecting widespread impacts since those same temperatures
occurred just a few days ago, but some sensitive vegetation which
has just recently budded/sprouted could be affected.

Friday will be a warm day, with widespread 60s/70s in western
Montana and central Idaho. Another disturbance then looks on track
to quickly swing through the Northern Rockies Saturday. Most of
the activity should remain east of the Continental Divide, but
model variability hints that it could deepen and have more impact
for our area. Currently, it appears the main affect would be
showers with a bit of wind, though a deeper trough would bring
more of both. Drier weather and a warming trend is expected under
northwesterly flow aloft for the second half of the week and into
early next week.

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...WINTER WEATHER ADVISORY until 9 AM MDT Wednesday
     Bitterroot/Sapphire Mountains...Butte/Blackfoot Region.

     WINTER STORM WARNING until 9 PM MDT this evening for Homestake
     Pass in the Butte/Blackfoot Region.

ID...WINTER WEATHER ADVISORY until 9 AM MDT Wednesday Eastern Lemhi
     County.

&&

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE MISSOULA MT
1037 AM MDT TUE APR 14 2015

...TIME...  ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
...DATE...  ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0834 AM     HEAVY SNOW       6 WSW SYRINGA           46.10N 115.83W
04/14/2015  M1.1 INCH        IDAHO              ID   TRAINED SPOTTER

            REPORTED THAT IT SNOWED 1.1" BETWEEN 8 AND 9
            AM PDT.

&&

NWS MISSOULA MT
IRIS SYSTEM