High Wind in Montana, January 13, 2009

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
1026 AM MST TUE JAN 13 2009

.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH THURSDAY...
UPDATE THIS MORNING MAINLY TO ADJUST TEMPERATURES AND
PRECIPITATION TYPES FOR TODAY. WARM AIR HAS INVADED THE SOUTHWEST
ZONES WHILE THE NORTHEAST REMAINS COLD. SURFACE LOW OVER SOUTHERN
SASKATCHEWAN EXPECTED TO SLIDE SOUTH ALONG FRONT OVER EASTERN
MONTANA TODAY. BEST CHANCE OF PRECIPITATION WILL BE JUST TO THE
EAST OF THE FRONT WHICH EXTENDS FROM SWIFT CURRENT TO SCOBEY TO
JUST WEST OF SIDNEY. WHILE WARMER AIR IS TO THE WEST OF THE
FRONT...SHALLOW INVERSION KEEPING COLDER AIR IN THE MILK/MISSOURI
VALLEYS. ADJUSTED TEMPERATURES TO REFLECT WHERE THE COLD AIR WILL
LINGER. SPREAD MIX OF PRECIPITATION FURTHER EAST TO REFLECT THE
WARMER AIR ALOFT...LEFT JUST SNOW IN FAR NORTHEAST TO THE LEFT OF
THE TRACK OF THE LOW.

AS LOW MOVES ACROSS NORTHEAST MONTANA THIS AFTERNOON...WINDS WILL
INCREASE BEHIND IT...AND CONTINUE INTO THE EVENING. WINDS EXPECTED
TO BE STRONG ENOUGH TO PRODUCE SOME BLOWING SNOW THIS EVENING
ALTHOUGH LITTLE LOOSE SNOW EXCEPT IN THE NORTHEAST. HAVE THUS
TRIMMED BACK THE MENTION OF BLOWING SNOW TO AREAS WHERE STRONGEST
WINDS ARE EXPECTED. EBERT

PREVIOUS SHORT TERM DISCUSSION...LARGE SCALE PATTERN REMAINS VERY
AMPLIFIED...WITH A LARGE HIGH PRESSURE ALOFT OVER THE PACIFIC
COAST STATES...CENTERED OVER CA COAST. NE MT IS IN A VERY STRONG
NW FLOW AROUND THIS HIGH...UP TO 150 KT AS SHOWN ON 00Z KGGW
SOUNDING. SATELLITE CHANNELS HAVE BEEN SHOWING QUITE A BIT OF
MOISTURE/CLOUDS MOVING OUR WAY IN THIS FLOW OVERNIGHT...BUT ONLY
WEAK SHORTWAVE ACTIVITY. WARM FRONT MOVING E ACROSS OUR W MOST
ZONES IS PROVIDING SOME LIFT FOR LIGHT SNOW IN OUR E...BUT
CONTINUING TO LOOK RATHER SPOTTY AND LIGHT AND LESS THAN
PREVIOUSLY EXPECTED. THE MAIN SHORTWAVE IN NW FLOW MOVES OFF INTO
ND AND WITH LESSENING OVERRUNNING...EXPECT ONLY SCATTERED LIGHT
ACCUMULATIONS TODAY. THE WARM FRONT HAS ALREADY CAUSED TEMPS TO
CLIMB WELL ABOVE FREEZING IN OUR SW. THIS WILL SPREAD E ACROSS THE
ENTIRE AREA TODAY AS THICKNESSES CLIMB TO THE 530S DM. MUCH OF THE
AREA WILL CLIMB TO THE 30S AND LOWER 40S FOR HIGHS.

THE LAST IN THE CURRENT STRING OF ARCTIC HIGHS IS QUICKLY
INTENSIFYING OVER NW CANADA THIS MORN. THIS WILL CONTINUE TO
INTENSIFY...TO A 1045-1050 MB CENTER...AS IT MOVES INTO W ND WED.
THIS SIMILAR TO THE PATTERN OF 2 DAYS AGO...WITH A SHARP ARCTIC
FRONTAL PASSAGE FOR NE NT TONIGHT...BUT COLDER AIR FOLLOWING THIS
FRONT. 850 MB WINDS ARE UP TO 50 KT...JUST A LITTLE LESS THAN THE
PREVIOUS FRONT THAT PRODUCED OVER 70 MPH WINDS...BUT NOT AS WELL
LINKED WITH THE STRONGER COLD ADVECTION. EVEN SO...MODELS SHOW UP
TO 40 KT WINDS AT 850 MB DURING THE MOST FAVORABLE LAPSE RATE
TIMES...WHICH ALSO SHOW SUPER ADIABATIC LAPSE RATES
AGAIN...INDICATIVE OF THE LOWER LEVEL TURBULENCE...AND SO WILL
HAVE WIDESPREAD BLOWING AND DRIFTING OF SNOW AGAIN. SIMILAR TO
LAST SYSTEM MODELS INDICATE ONLY LIGHT QPF...AND A PAIR OF RATHER
WEAK VORTICITY CENTERS JUST BRUSHING OUR NE. WILL LEAVE ANY
ADVISORY CONSIDERATIONS FOR THE DAY SHIFT...WHICH LOOK MOST
FAVORABLE AGAIN IN OUR N DUE TO THE POTENTIAL OF BLOWING SNOW AS
WELL AS WIND CHILL.

WARM FRONT MOVES BACK ACROSS THE AREA THU IN A PATTERN SIMILAR TO
YESTERDAY...BUT WITH LESS FAVORABLE LIFT/UPPER SUPPORT AND AIRMASS
DEPTH...SO KEEPING POPS VERY LOW.

.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...
MODELS REMAIN IN GOOD AGREEMENT FOR THE MOST PART THRU THE
EXTENDED PERIOD. IT APPEARS THAT THE END OF THIS WEEK THRU EARLY
NEXT WEEK WILL BE ONE OF THE NICEST STRETCHES WE HAVE HAD FOR SOME
TIME AS WE WILL BE UNDER THE EFFECTS A BIG UPPER RIDGE. THE
BEGINNING OF THE PERIOD ON THURSDAY NIGHT HAS THE WESTERN UPPER
RIDGE AXIS FAR ENUF EAST TO PUSH THE ARCTIC AIR INTO THE DAKOTAS
AND GIVE US 850 MB TEMPERATURES ABOVE ZERO CELSIUS. THE WARM AIR
ADVECTION THEN CONTINUES THRU THE WEEKEND AND EARLY NEXT WEEK AS
THE RIDGE AXIS MOVES EAST. ONLY REAL WRINKLE AMONGST THE MODELS IS
THE HANDLING OF A FAST-MOVING UPPER DISTURBANCE IN THE NORTHWEST
FLOW FRIDAY NIGHT INTO SATURDAY. OPERATIONAL GFS IS THE ODD MODEL
OUT WITH THIS FEATURE WITH RESPECT TO IT BEING MOIST ENUF HERE TO
GENERATE SOME LIGHT PRECIPITATION AS IT MOVES DIRECTLY OVERHEAD.
REMAINING OPERATIONAL MODELS TAKE THIS FEATURE FARTHER EAST INTO
THE DAKOTAS AND LEAVE THE LOWER LEVELS OF THE ATMOSPHERE HERE ON
THE DRY SIDE. SO FOR NOW WILL KEEP THINGS DRY AND SIMPLY ADD IN
SOME CLOUDS TO ACCOUNT FOR THE PASSAGE OF THIS WAVE. OTHERWISE NOT
EXPECTING MUCH IN THE WAY OF CLOUDS THRU MOST OF THE EXTENDED
PERIOD. TEMPERATURES WILL DEFINITELY BE WARMER THAN WE HAVE HAD
FOR SOME TIME. BIG QUESTION IS THE AMOUNT OF MIXING TO GET THE
WARM AIR DOWN TO THE SURFACE...AS OTHERWISE THE SNOW COVER WILL
AID IN KEEPING TEMPERATURES ON THE COOL SIDE DESPITE THE MILD AIR
ALOFT. FOR NOW WILL KEEP THE WARMING TEMPERED...ESPECIALLY AT
NIGHT AND FOR THE NORTHEAST HALF OR SO OF THE CWA. BUT IT WILL
STILL BE RELATIVELY MILD NONETHELESS. AS THE WEEK UNFOLDS
EXPECTING THAT A BETTER DETERMINATION OF EXPECTED WIND AND MIXING
CAN BE MADE.

&&

.AVIATION...
ANOTHER SYSTEM SLATED TO MOVE ACROSS THE AREA TODAY. SO SOME LOWER
CEILINGS ARE EXPECTED AS WELL AS SOME LIGHT SNOW WHICH MAY REDUCE
VISIBILITY AT TIMES. IN GENERAL VFR CONDITIONS EARLY THIS MORNING
WILL BE GIVING WAY TO MVFR WITH SOME OCCASIONAL IFR. A COLD FRONT
WILL MOVE THRU LATE THIS AFTERNOON OR EARLY EVENING AND BRING A
WIND SHIFT TO NORTHWEST AND SPEEDS WILL INCREASE TO 15-25 KT.
TONIGHT ANY SNOW WILL BE ENDING AND CEILINGS ARE EXPECTED TO RISE
TO VFR. NORTHWEST WIND BECOMES NORTH AND GRADUALLY DECREASES TO
NEAR 10 KT BY WEDNESDAY MORNING. VFR CONDITIONS EXPECTED WEDNESDAY
WITH LIGHT WIND UNDER SURFACE HIGH PRESSURE.

&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

WEATHER.GOV/GLASGOW

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE GLASGOW MT
642 AM MST TUE JAN 13 2009

MTZ018-019-061-062-141200-
DANIELS-SHERIDAN-NORTHERN VALLEY-EASTERN ROOSEVELT-
642 AM MST TUE JAN 13 2009

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHEAST
MONTANA.

.DAY ONE...TODAY AND TONIGHT

WINDS SHIFTING TO NORTH AND INCREASING TO 15 TO 30 MPH WILL CAUSE
BLOWING AND DRIFTING OF SNOW ALONG WITH POOR VISIBILITIES AGAIN
TONIGHT. BRIEF GUSTS TO OVER 40 MPH ARE ALSO EXPECTED. THERE IS A
CHANCE OF NEW SNOWFALL...BUT AMOUNTS SHOULD BE LIGHT...WELL UNDER
AN INCH. EXPECT STEADILY FALLING TEMPERATURES OVERNIGHT TO BELOW
ZERO BY WEDNESDAY MORNING ALONG WITH WIND CHILL READINGS DROPPING
TO 20 TO 30 BELOW ZERO.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.

MTZ016-017-020>027-059-060-141200-
CENTRAL AND SOUTHEAST PHILLIPS-CENTRAL AND SOUTHERN VALLEY-
WESTERN ROOSEVELT-PETROLEUM-GARFIELD-MCCONE-RICHLAND-DAWSON-
PRAIRIE-WIBAUX-NORTHERN PHILLIPS-SOUTHWEST PHILLIPS-
642 AM MST TUE JAN 13 2009

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHEAST
MONTANA.

.DAY ONE...TODAY AND TONIGHT

NORTHWEST WINDS SHIFTING TO NORTH AND INCREASING TO 15 TO 30 MPH
WILL CAUSE AREAS OF BLOWING AND DRIFTING SNOW...AND REDUCED
VISIBILITIES AT TIMES AGAIN TONIGHT. BRIEF GUSTS TO OVER 40 MPH
ARE ALSO EXPECTED. THERE IS A CHANCE OF NEW SNOWFALL...BUT AMOUNTS
SHOULD BE LIGHT...WELL UNDER AN INCH. TEMPERATURES TONIGHT WILL
BE SIGNIFICANTLY COLDER THAN MONDAY NIGHT.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.