Winter Storm Watch 4, NWS Missoula, MT

210 
WWUS45 KMSO 061113
WSWMSO

URGENT - WINTER WEATHER MESSAGE
NATIONAL WEATHER SERVICE MISSOULA MT
413 AM MST SUN FEB 6 2011

MTZ002-062200-
/O.UPG.KMSO.WS.A.0004.110206T1800Z-110208T0000Z/
/O.NEW.KMSO.WS.W.0005.110207T0000Z-110208T0000Z/
WEST GLACIER REGION-
413 AM MST SUN FEB 6 2011

...WINTER STORM WARNING IN EFFECT FROM 5 PM THIS AFTERNOON TO
5 PM MST MONDAY...

THE NATIONAL WEATHER SERVICE IN MISSOULA HAS ISSUED A WINTER
STORM WARNING FOR SNOW AND BLOWING SNOW...WHICH IS IN EFFECT
FROM 5 PM THIS AFTERNOON TO 5 PM MST MONDAY. THE WINTER STORM
WATCH IS NO LONGER IN EFFECT. 

* IMPACTS/TIMING: SNOW WILL BEGIN TO FALL LATE THIS AFTERNOON AND
  CONTINUE THROUGH MONDAY. SNOWFALL IS EXPECTED TO INTENSIFY
  OVERNIGHT TONIGHT...BECOMING MODERATE TO HEAVY AT TIMES. ARCTIC
  AIR WILL BEGIN TO SPILL OVER THE CONTINENTAL DIVIDE MONDAY
  MORNING...PRODUCING GUSTY NORTHEAST WINDS AND BLOWING/DRIFTING
  OF SNOW. THE COMBINATION OF SNOW AND BLOWING SNOW COULD QUICKLY
  REDUCE VISIBILITIES AT TIMES THROUGH MONDAY. HAZARDOUS DRIVING
  CONDITIONS SHOULD BE ANTICIPATED DUE TO SNOW...BLOWING SNOW AND
  SLICK SNOW-COVERED ROADWAYS.

* SNOW ACCUMULATIONS: 5 TO 10 INCHES AT LOWER ELEVATIONS WITH UP 
  TO 15 INCHES OVER MOUNTAIN PASSES/HIGHER ELEVATIONS. 

* WINDS: WINDS WILL BEGIN TO INCREASE MONDAY MORNING BECOMING
  NORTHEAST SUSTAINED AT 15 TO 25 MPH WITH GUSTS TO 35 MPH THROUGH
  MONDAY AFTERNOON...MAINLY ALONG THE HIGHWAY 2 TRAVEL CORRIDOR.

* LOCATIONS IMPACTED INCLUDE...BAD ROCK CANYON...ESSEX...HIGHWAY 
  83 BIGFORK TO SWAN LAKE...MARIAS PASS...POLEBRIDGE

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A WINTER STORM WARNING MEANS SIGNIFICANT AMOUNTS OF SNOW OR BLOWING
SNOW ARE EXPECTED OR OCCURRING. STRONG WINDS ARE ALSO EXPECTED.
THIS WILL MAKE TRAVEL VERY HAZARDOUS OR IMPOSSIBLE.

&&

$$

MTZ043-062200-
/O.UPG.KMSO.WS.A.0004.110206T1800Z-110208T0000Z/
/O.NEW.KMSO.WS.W.0005.110207T0000Z-110208T0600Z/
POTOMAC/SEELEY LAKE REGION-
413 AM MST SUN FEB 6 2011

...WINTER STORM WARNING IN EFFECT FROM 5 PM THIS AFTERNOON TO
11 PM MST MONDAY...

THE NATIONAL WEATHER SERVICE IN MISSOULA HAS ISSUED A WINTER
STORM WARNING FOR SNOW AND BLOWING SNOW...WHICH IS IN EFFECT
FROM 5 PM THIS AFTERNOON TO 11 PM MST MONDAY. THE WINTER STORM
WATCH IS NO LONGER IN EFFECT. 

* IMPACTS/TIMING: SNOW WILL BEGIN TO FALL LATE THIS AFTERNOON AND
  CONTINUE THROUGH MONDAY EVENING. SNOWFALL IS EXPECTED TO
  INTENSIFY OVERNIGHT TONIGHT...BECOMING MODERATE TO HEAVY AT
  TIMES. ARCTIC AIR WILL BEGIN TO SPILL OVER THE CONTINENTAL
  DIVIDE MONDAY MORNING...PRODUCING GUSTY NORTHEAST WINDS AND
  BLOWING/DRIFTING OF SNOW. THE COMBINATION OF SNOW AND BLOWING
  SNOW COULD QUICKLY REDUCE VISIBILITIES AT TIMES THROUGH MONDAY.
  HAZARDOUS DRIVING CONDITIONS SHOULD BE ANTICIPATED DUE TO
  SNOW...BLOWING SNOW AND SLICK SNOW-COVERED ROADWAYS.

* SNOW ACCUMULATIONS: 5 TO 10 INCHES AT LOWER ELEVATIONS WITH UP
  TO 15 INCHES OVER THE HIGHER ELEVATIONS.

* WINDS: WINDS WILL BEGIN TO INCREASE MONDAY MORNING...BECOMING
  NORTHEAST SUSTAINED AT 15 TO 25 MPH WITH GUSTS TO 35 MPH THROUGH
  MONDAY AFTERNOON...MAINLY ALONG THE HIGHWAY 200 TRAVEL CORRIDOR.

* LOCATIONS IMPACTED INCLUDE...HIGHWAY 200 BONNER TO GREENOUGH...HIGHWAY
  83 SEELEY LAKE TO CONDON...I-90 EAST MISSOULA TO BEARMOUTH

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A WINTER STORM WARNING MEANS SIGNIFICANT AMOUNTS OF SNOW OR BLOWING
SNOW ARE EXPECTED OR OCCURRING. STRONG WINDS ARE ALSO EXPECTED.
THIS WILL MAKE TRAVEL VERY HAZARDOUS OR IMPOSSIBLE.

&&

$$

MTZ003-062200-
/O.NEW.KMSO.WS.W.0005.110207T0700Z-110208T0000Z/
FLATHEAD/MISSION VALLEYS-
413 AM MST SUN FEB 6 2011

...WINTER STORM WARNING IN EFFECT FROM MIDNIGHT TONIGHT TO 5 PM
MST MONDAY FOR THE FLATHEAD VALLEY...

THE NATIONAL WEATHER SERVICE IN MISSOULA HAS ISSUED A WINTER
STORM WARNING FOR SNOW AND BLOWING SNOW FOR THE FLATHEAD
VALLEY...WHICH IS IN EFFECT FROM MIDNIGHT TONIGHT TO 5 PM MST
MONDAY.


* IMPACTS/TIMING: SNOW WILL BEGIN TO FALL THIS EVENING AND
  CONTINUE THROUGH MONDAY. SNOWFALL IS EXPECTED TO INTENSIFY
  MONDAY MORNING...BECOMING MODERATE TO HEAVY AT TIMES. ARCTIC AIR
  WILL BEGIN TO SPILL OVER THE CONTINENTAL DIVIDE MONDAY MORNING
  AS WELL...PRODUCING GUSTY NORTHEAST WINDS AND BLOWING/DRIFTING
  OF SNOW. THE COMBINATION OF SNOW AND BLOWING SNOW COULD QUICKLY
  REDUCE VISIBILITIES AT TIMES THROUGH MONDAY...PARTICULARLY
  DURING THE MORNING COMMUTE. HAZARDOUS DRIVING CONDITIONS SHOULD
  BE ANTICIPATED DUE TO SNOW...BLOWING SNOW AND SLICK SNOW-COVERED
  ROADWAYS. LOCATIONS SOUTH OF FLATHEAD LAKE WILL SEE SNOW BY
  MONDAY AFTERNOON...BUT IMPACTS DUE TO SNOW AND WIND ARE EXPECTED
  TO BE MINIMAL.

* SNOW ACCUMULATIONS: 2 TO 5 INCHES IN THE FLATHEAD VALLEY...LOCALLY
  UP TO 7 IN WHITEFISH AND COLUMBIA FALLS. SNOW ACCUMULATIONS MAY
  BE DIFFICULT TO MEASURE DUE TO BLOWING AND DRIFTING. 1 TO 2
  INCHES CAN BE EXPECTED SOUTH OF FLATHEAD LAKE.

* WINDS: WINDS WILL BEGIN TO INCREASE MONDAY MORNING BECOMING
  NORTHEAST SUSTAINED AT 15 TO 25 MPH WITH GUSTS TO 40 MPH THROUGH
  MONDAY AFTERNOON...MAINLY IN THE NORTHERN FLATHEAD VALLEY.


PRECAUTIONARY/PREPAREDNESS ACTIONS...

A WINTER STORM WARNING MEANS SIGNIFICANT AMOUNTS OF SNOW OR BLOWING
SNOW ARE EXPECTED OR OCCURRING. STRONG WINDS ARE ALSO POSSIBLE.
THIS WILL MAKE TRAVEL VERY HAZARDOUS OR IMPOSSIBLE.

&&

$$

MTZ007-062200-
/O.NEW.KMSO.WW.Y.0016.110207T1800Z-110208T0600Z/
BUTTE/BLACKFOOT REGION-
413 AM MST SUN FEB 6 2011

...WINTER WEATHER ADVISORY IN EFFECT FROM 11 AM TO 11 PM MST
MONDAY...

THE NATIONAL WEATHER SERVICE IN MISSOULA HAS ISSUED A WINTER
WEATHER ADVISORY FOR SNOW AND BLOWING SNOW...WHICH IS IN EFFECT
FROM 11 AM TO 11 PM MST MONDAY. 

* IMPACTS/TIMING: SNOW WILL BEGIN TO FALL THIS EVENING AND
  CONTINUE THROUGH MONDAY EVENING. SNOWFALL IS EXPECTED TO
  INTENSIFY MONDAY MORNING...BECOMING MODERATE TO HEAVY AT TIMES.
  ARCTIC AIR WILL BEGIN TO SPILL OVER THE CONTINENTAL DIVIDE
  MONDAY MORNING AS WELL...PRODUCING GUSTY EAST WINDS AND
  BLOWING/DRIFTING OF SNOW. THE COMBINATION OF SNOW AND BLOWING
  SNOW COULD QUICKLY REDUCE VISIBILITIES AT TIMES THROUGH MONDAY
  EVENING. HAZARDOUS DRIVING CONDITIONS SHOULD BE ANTICIPATED DUE
  TO SNOW...BLOWING SNOW AND SLICK SNOW-COVERED ROADWAYS.
  LOCATIONS SOUTH OF HIGHWAY 12 WILL SEE SNOW BY MONDAY AFTERNOON...BUT
  IMPACTS DUE TO SNOW AND WIND ARE EXPECTED TO BE MINIMAL.

* SNOW ACCUMULATIONS: 2 TO 5 INCHES NORTH OF HIGHWAY 12. SNOW
  ACCUMULATIONS MAY BE DIFFICULT TO MEASURE DUE TO BLOWING AND
  DRIFTING. 1 TO 2 INCHES CAN BE EXPECTED SOUTH OF HIGHWAY 12.

* WINDS: WINDS WILL BEGIN TO INCREASE LATE MONDAY MORNING BECOMING
  EAST SUSTAINED AT 15 TO 25 MPH WITH GUSTS TO 35 MPH THROUGH
  MONDAY EVENING...MAINLY ALONG THE HIGHWAY 200 AND HIGHWAY 12
  TRAVEL CORRIDORS.

* LOCATIONS IMPACTED INCLUDE...HIGHWAY 12 GARRISON TO
  ELLISTON...MACDONALD PASS...HIGHWAY 200 THROUGH OVANDO

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A WINTER WEATHER ADVISORY MEANS THAT PERIODS OF SNOW OR BLOWING
SNOW WILL CAUSE TRAVEL DIFFICULTIES. BE PREPARED FOR SLIPPERY
ROADS AND LIMITED VISIBILITIES...AND USE CAUTION WHILE DRIVING.


&&

$$

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
300 PM MST SAT FEB 5 2011

.DISCUSSION...UNSETTLED NORTHWEST FLOW ALOFT AND MOISTURE
STREAMING AROUND A HIGH PRESSURE RIDGE OFF THE WEST COAST HAVE
SUPPORTED A FEW MOUNTAIN SNOW SHOWERS THIS AFTERNOON. ALTHOUGH
SHOWERS ARE EXPECTED TO TAPER OFF THROUGH THE EVENING...ANOTHER
SURGE OF MOISTURE WILL KEEP PRECIPITATION CHANCES GOING THROUGH
THE OVERNIGHT HOURS. ICY ROAD CONDITIONS COULD BECOME A NUISANCE
TO TRAVELERS ONCE AGAIN AS WET ROADWAYS RE-FREEZE OVERNIGHT
THROUGH MID TO LATE SUNDAY MORNING.

A MORE ENERGETIC PACIFIC SYSTEM WILL BEGIN TO IMPACT THE NORTHERN
ROCKIES SUNDAY AFTERNOON THROUGH MONDAY. MOUNTAINS AND PASSES
SHOULD BEAR THE BRUNT OF THE STORM WITH MODERATE TO HEAVY SNOW
ACCUMULATIONS ANTICIPATED AS THE SURFACE LOW TRACKS NORTHWEST TO
SOUTHEAST. ALL BUT THE LOWEST VALLEYS OF NORTH CENTRAL IDAHO
SHOULD PICK UP LIGHT TO MODERATE SNOW ACCUMULATIONS. AS THE LOW
DEEPENS OVER WESTERN MONTANA LATE SUNDAY NIGHT...A TIGHTENING
SURFACE PRESSURE GRADIENT WILL DEVELOP AND PRODUCE GUSTY WINDS
ACROSS NORTH CENTRAL IDAHO AND WEST CENTRAL/SOUTHWEST MONTANA. THE
LOWER HELLS CANYON/GRANGEVILLE AREAS WILL LIKELY SEE WIND GUSTS OF
40 MPH LATE SUNDAY NIGHT THROUGH MONDAY MORNING...WHILE THE
BITTERROOT VALLEY AND INTERSTATE 90 CORRIDOR FROM ANACONDA TO DEER
LODGE SHOULD EXPERIENCE WIND GUSTS TO AROUND 35 MPH DURING THE
SAME TIME-FRAME. THE GUSTY WINDS WILL LIKELY DOWNSLOPE SOME OF THE
WIDER VALLEYS OF WEST CENTRAL/SOUTHWEST MONTANA...KEEPING THE
ATMOSPHERE WELL-MIXED AND LOW TEMPERATURES WELL ABOVE NORMAL. A
WINTER STORM WATCH HAS BEEN ISSUED FOR SNOW ALONG THE NORTHERN
DIVIDE AND A WIND ADVISORY HAS BEEN ISSUED FOR THE LOWER HELLS
CANYON/GRANGEVILLE AREAS. PLEASE SEE WWW.WEATHER.GOV/MISSOULA FOR
THE MOST CURRENT INFORMATION.

MONDAY AND MONDAY NIGHT...
THE UPPER FLOW PATTERN WILL BECOME MORE NORTHERLY AS A PACIFIC
NORTHWEST TROUGH OF LOW PRESSURE DIGS TOWARDS CALIFORNIA. THIS
TREND WILL DRAW MUCH COLDER INTO WESTERN MONTANA AND NORTHERN
IDAHO. SNOW IS EXPECTED TO CONTINUE MONDAY WITH EVENING LOWER
ELEVATIONS SEEING A CHANGE OVER TO SNOW ON MONDAY. ARCTIC AIR
(ALTHOUGH NOT AS COLD AS THE PREVIOUS CANADIAN SURGE) WILL BE
USHERED THROUGH THE GAPS OF THE CONTINENTAL DIVIDE BY STRONG EAST
TO NORTHEAST WINDS. EXIT POINTS THROUGH THESE GAPS...LIKE HELLGATE
CANYON (EAST MISSOULA) AND BADROCK CANYON (NORTH OF KALISPELL)
WILL ONCE AGAIN TAKE THE BRUNT OF THE WINDS MONDAY INTO MONDAY
EVENING...BEFORE DECREASING MONDAY NIGHT. EXPECT ACCUMULATING
SNOWFALL ACROSS MUCH OF WESTERN MONTANA AND NORTHERN IDAHO DURING
THIS PERIOD. THE INFLUX OF ARCTIC AIR WILL TAKE PLACE EARLY MONDAY
MONDAY THROUGH THE GLACIER PARK REGION AND NORTHERN FLATHEAD
VALLEY. TIMING OF COLD AIR INTO THE WEST-CENTRAL MONTANA
(INCLUDING THE MISSOULA AREA) BY LATE AFTERNOON/EARLY MONDAY
EVENING. A WINTER STORM WATCH HAS BEEN ISSUED FOR THE WEST GLACIER
AND SEELEY LAKE/POTOMAC REGIONS.

TUESDAY...DRIER...BUT STILL VERY COLD AIR WILL FILTER INTO THE
NORTHERN ROCKIES REGION AS A NORTHERLY FLOW MAINTAINS THE COLD
INFLUX. THE SURFACE PRESSURE GRADIENT WILL BE RELAXING WITH
DECREASING WINDS. SKIES WILL ALSO SEE SOME CLEARING ACROSS
NORTHWEST MONTANA.

WEDNESDAY MORNING WILL LIKELY BE THE COLDEST DAY WITH ALL MODELS
SHOWING STABLE CONDITIONS WITH LITTLE WIND OVER THE NORTHERN
ROCKIES. THE TEMPERATURES IN FAVORED LOCATIONS FOR COLD WILL LIKELY
PLUMMET OVERNIGHT AS LONG AS THE MODEL FORECAST OF CLEARING
CONDITIONS HOLDS TRUE. HOWEVER THE POTENTIAL CLEARING APPEARS SHORT
LIVED AS ANOTHER SWATH OF MOISTURE DROPS OUT OF CANADA WEDNESDAY
AFTERNOON INTO THURSDAY EVENING. BOTH THE GFS AND ECMWF ARE SHOWING
A BIT OF ENHANCED LIFTING POSSIBLE AS THE EXITING REGION OF AN
UPPER LEVEL JET STREAK NOSES OVER WESTERN MONTANA. THIS COULD RESULT
IN A PERIOD OF LIGHT SNOWFALL CONSIDERING THAT THE TEMPERATURES
FROM THE SURFACE TO ABOVE THE MOUNTAINS ARE WELL BELOW FREEZING AND
FALL WITHIN THE SNOW GROWTH REGION. BUT AT THIS TIME MOISTURE
APPEARS TO BE LIMITED SO HAVE CAUTIOUSLY INCREASED CHANCES FOR
PRECIPITATION MAINLY FOR LOCATIONS NORTH OF INTERSTATE 90.

THERE IS STILL A GOOD DEAL OF UNCERTAINTY REGARDING THE FORECAST
PATTERN FROM THURSDAY THROUGH NEXT WEEKEND. HOWEVER THERE IS
INCREASING CONFIDENCE THAT THERE WILL BE A PATTERN SHIFT OCCURRING
NEXT WEEKEND. THIS PATTERN WOULD LIKELY BRING MODERATING
TEMPERATURES AS THE AMPLIFIED RIDGE WHICH HAS BEEN PRESENT OVER THE
PACIFIC COASTLINE FOR SOME TIME NOW BREAKS DOWN LEADING TO MORE
TROUGHING UNDER AN APPARENT INCREASINGLY MOIST...WESTERLY FLOW. THUS
THE FORECAST WAS ADJUSTED BY KEEPING GOOD CHANCES FOR PRECIPITATION
NEXT WEEKEND WHILE INCREASING SNOW LEVELS AS WELL AS TEMPERATURES.
OVERALL CONDITIONS DO NOT APPEAR TO WARM SIGNIFICANTLY AND SHOULD
REMAIN NEAR TO SLIGHTLY ABOVE NORMAL.

&&

.AVIATION...VERY PLEASANT FLYING CONDITIONS ARE EXPECTED THROUGH THE
NIGHTTIME HOURS AS DRIER AIR SETTLES OVER THE NORTHERN ROCKIES.
BUT BY MORNING...CLOUDS AND MOISTURE WILL BE ON THE INCREASE WITH
THE POTENTIAL FOR LIGHT SNOW BEGINNING AT KGPI EARLY IN THE
MORNING AND CONTINUING THROUGHOUT THE DAY. SNOW WILL SPREAD
SOUTH...IMPACTING KMSO BY MID MORNING WITH LOWER CEILINGS AND
THE POTENTIAL FOR REDUCTIONS IN VISIBILITY. INCREASING AND
LOWERING CLOUDS ARE FORECAST FOR KBTM AND KSMN BUT AT THIS TIME IT
DOES NOT APPEAR AS THOUGH PRECIPITATION WILL AFFECT VISIBILITY
OVER THE NEXT TWENTY-FOUR HOURS.

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...WINTER STORM WATCH FROM SUNDAY MORNING THROUGH MONDAY AFTERNOON
     POTOMAC/SEELEY LAKE REGION...WEST GLACIER REGION.

ID...WIND ADVISORY FROM 10 PM SUNDAY TO 10 AM PST MONDAY FOR
     GRANGEVILLE AND VICINITY.

&&

SHORT TERM...DEROSA
LONG TERM....MSJ
AVIATION...DICKERSON