Flood in Idaho, January 8 to 12, 2010

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
1058 AM MST FRI JAN 8 2010

.UPDATE...

WIND CHILL ADVISORY EXTEND FOR INTERSTATE 90 CORRIDOR FROM
DOWNTOWN MISSOULA TO THE BEARMOUTH EXIT.

&&

.DISCUSSION...

COLD AND WINDS CONTINUE TO BE AN IMPACT IN THE CANYON AREA OF
INTERSTATE 90 EAST OF MISSOULA. THEREFORE..THE WIND CHILL ADVISORY
HAS BEEN EXTENDED THROUGH EARLY THIS AFTERNOON.

&&

.AVIATION...A RIDGE OF HIGH PRESSURE WILL REMAIN ANCHORED OVER
THE NORTHERN ROCKIES FRIDAY. SOME MOISTURE IS EXPECTED TO PASS
THROUGH THE RIDGE TODAY...CREATING SOME CLOUD COVER WHICH MAY
OBSCURE THE MOUNTAINS AND PASSES PERIODICALLY. IN ADDITION...A LOW
STRATUS DECK HAS FORMED OVER FLATHEAD LAKE AND IS EXPECTED TO
PERSIST INTO THE AFTERNOON HOURS. IN ADDITION TO OBSCURING THE
TERRAIN...LIGHT SNOW MAY PERIODICALLY CREATE LOWERED VISIBILITY.
AN APPROACHING STORM SYSTEM WILL BEGIN TO SPREAD LIGHT
PRECIPITATION INTO NORTHWEST MONTANA AND NORTH CENTRAL IDAHO AFTER
09/0600. INCREASING TERRAIN OBSCURATIONS AND VISIBILITY REDUCTIONS
CAN BE EXPECTED DUE TO RAIN AND SNOW SHOWERS INTO SATURDAY
MORNING.

&&

.PREV DISCUSSION... /ISSUED 934 AM MST FRI JAN 8 2010/

UPDATE...

WIND CHILL ADVISORY EXPANDED ALONG INTERSTATE 90 CORRIDOR EAST OF
MISSOULA FOR THIS MORNING.

DISCUSSION...

COLD AIR WILL CONTINUE TO BE PRESENT THROUGHOUT WESTERN MONTANA
AND NORTH CENTRAL IDAHO TODAY...WITH HIGH PRESSURE OVER THE
REGION. SIMILAR TO THURSDAY MORNING...EAST WINDS ALONG THE
INTERSTATE 90 CORRIDOR EAST OF MISSOULA HAVE DEVELOPED...PRODUCING
WIND CHILL BETWEEN 10 AND 20 DEGREES BELOW ZERO. THE PREVIOUSLY
ISSUED WIND CHILL ADVISORY HAS BEEN EXPANDED TO NOW INCLUDE
INTERSTATE 90 FROM DOWNTOWN MISSOULA TO THE BEARMOUTH EXIT.

PREV DISCUSSION... /ISSUED 351 AM MST FRI JAN 8 2010/

DISCUSSION...A RIDGE OF HIGH PRESSURE WILL REMAIN ANCHORED OVER
THE NORTHERN ROCKIES TODAY. WITH STRONG VALLEY INVERSIONS AND COLD
TEMPERATURES OVERNIGHT...TEMPERATURES WILL BE SLOW TO WARM THIS AFTERNOON.
A WIND CHILL ADVISORY WILL REMAIN IN EFFECT FOR DOWNTOWN MISSOULA
AND HELLGATE CANYON THROUGH THIS MORNING AS STEADY EAST WINDS
CONTINUE TO PRODUCE DANGEROUSLY COLD WIND CHILLS. WINDS ARE
EXPECTED TO RELAX HERE BY LATE MORNING. IN ADDITION...A LOW
STRATUS DECK OVER FLATHEAD LAKE WILL CONTINUE TO HAVE THE
POTENTIAL TO PRODUCE LIGHT SNOW SHOWERS ALONG THE LAKE TODAY.
LITTLE TO NO ACCUMULATION IS EXPECTED.

A PACIFIC WEATHER SYSTEM IS EXPECTED TO PUSH THROUGH THE NORTHERN
ROCKIES AFTER MIDNIGHT TONIGHT. WITH THIS FEATURE...THE UPPER
LEVEL FLOW WILL BECOME MORE SOUTHWESTERLY WHICH WILL BRING A
MILDER AIR MASS OVER THE REGION. FORECAST MODELS HAVE CONTINUED TO
WEAKEN THE INCOMING SYSTEM WITH THE LATEST RUNS...SO ALTHOUGH THE
CHANCE OF PRECIPITATION IS FAIRLY HIGH IN THE FORECAST...PRECIPITATION
AMOUNT ARE EXPECTED TO BE LIGHT. WITH WARMING AIR ALOFT AND COLD
AIR TRAPPED IN THE VALLEYS OF NORTH CENTRAL IDAHO AND WEST CENTRAL
MONTANA...A SLIGHT CHANCE OF LIGHT FREEZING RAIN REMAINS IN PLAY
FOR LATE FRIDAY NIGHT INTO SATURDAY MORNING. HIGHER ELEVATIONS AND
LOCATIONS ACROSS NORTHWEST MONTANA SHOULD REMAIN MOSTLY SNOW
THROUGH THIS EVENT. ACCUMULATIONS WILL BE LIGHT WITH ONLY AN INCH
OR TWO EXPECTED BY SATURDAY NIGHT.

SUNDAY THROUGH NEXT WEEK...MODELS CONTINUE TO DEPICT THE RIDGE OF
HIGH PRESSURE REBUILDING ACROSS THE NORTHERN ROCKIES. THIS RIDGE
WILL ALLOW FOR A MORE MILD AND DRIER TREND THROUGH MIDWEEK. BY
WEDNESDAY THE RIDGE WILL START TO BREAK DOWN IN ADVANCE OF THE
NEXT WEATHER SYSTEM. SINCE THERE ARE STILL TIMING ISSUES TO BE DEALT
WITH IN REGARDS TO THIS DISTURBANCE...ONLY MINOR CHANGES WERE
MADE TO THE FORECAST FROM WEDNESDAY ONWARD.

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...WIND CHILL ADVISORY UNTIL 1 PM MST THIS AFTERNOON FOR
     MISSOULA/BITTERROOT VALLEYS-POTOMAC/SEELEY LAKE REGION.

ID...NONE.
&&

UPDATE...ZUMPFE
SHORT TERM...PALLISTER
LONG TERM....ALLEGRETTO
AVIATION...PALLISTER