Winter Storm Watch 9, NWS Grand Forks, ND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND FORKS ND
336 AM CST FRI DEC 12 2008

.DISCUSSION...
THE MAIN CHALLENGE CONTINUES TO BE THE MAJOR STORM THAT WILL
IMPACT THE REGION SAT NIGHT THROUGH SUNDAY NIGHT. BEFORE I GET TO
THE DETAILS...WE WILL BE HOISTING A BLIZZARD WATCH FOR ALL BUT THE
FAR EAST (WHERE A WINTER STORM WATCH WILL BE ISSUED) FOR 00Z SUN-
12Z MONDAY. MODELS CONTINUE IN VERY GOOD AGREEMENT AND LITTLE
OVERALL DIFFERENCE NOTED...SO WILL USE A BLEND THIS MORNING.

FOR TODAY...A SHORTWAVE AND MID LEVEL WARM ADVECTION WILL MOVE
FROM NW TO SE THROUGH THE DAY INTO TONIGHT. THERE WILL BE A BAND
OF LIGHT SNOW...WITH GENERALLY LIGHT ACCUMULATIONS. TEMPS WILL BE
WARMER THAN RECENT DAYS.

ON SATURDAY/SAT NIGHT...A STRONG BAROCLINIC ZONE WILL CONTINUE TO
TIGHTEN AS THE FLOW ALOFT TURNS TO THE SW. STRONG LIFTING PER
OMEGA/Q VECTOR AND ISENTRIPIC FIELDS WILL INCREASE AND SATURATION
WILL OCCUR BY SATURDAY AFTERNOON IN THE NORTH AND TOWARDS SUNSET
IN THE FAR SOUTH. SNOW WILL BEGIN AND BECOME HEAVY SATURDAY NIGHT
IN ALL AREAS...AS A LEAD SHORTWAVE MOVES THROUGH THE REGION. WINDS
WILL TURN NORTHERLY IN THE VALLEY AND INCREASE AND GUST OVER 40
MPH...WITH CONSIDERABLE BLOWING AND DRIFTING SNOW FROM THE FINE
POWDER SNOW THAT WILL FALL. STRONG LOW LEVEL COLD AIR ADVECTION
WILL BEGIN BY 06Z SUNDAY...WITH ABOUT 40KT TO MIX...SO EXPECT
GUSTS OVER 40 MPH TO DEVELOP.

FOR SUN-SUN NIGHT...THE MAIN LOW PRESSURE AREA WILL MOVE INTO
NORTHWEST WISCONSIN. THERE WILL BE PLENTY OF FORCING FOR ASCENT
OVER OUR REGION THOUGH AS 700MB LOW MOVES ABOUT OVER GFK. THIS
WILL COUPLE WITH A CONTINUED TIGHTENING PRESSURE GRADIENT TO
CONTINUE THE BLOWING/DRIFTING SNOW AS WELL AS HEAVY SNOW AT TIMES
WITH A SFC INVERTED TROUGH. TEMPS WILL FALL BELOW ZERO ON
SUNDAY...ALONG WITH WIND CHILLS FALLING TO NEAR 40 BELOW BY SUNDAY
NIGHT.

THIS WILL BE A VERY DANGEROUS STORM...WITH ZERO VISIBILITY
POSSIBLE SAT NIGHT THROUGH SUN NIGHT. TRAVEL MAY BECOME IMPOSSIBLE
ON SUNDAY/SUN NIGHT WITH ROADS POSSIBLY DRIFTING SHUT...AND THIS MAY
BE A BLIZZARD THAT HASN/T BEEN SEEN IN THIS AREA SINCE THE
1996-1997 WINTER.

THIS SYSTEM WILL HAVE A TREMENDOUS BAROCLINIC ZONE WITH A STRONG
WARM CONVEYOR BELT MOVING OVER A LOW LEVEL COLD CONVEYOR BELT.
THERE WILL BE 0.5 INCH PWATS FOR THIS STORM AS WELL...AND
DEEP/SUSTAINED LIFT AND SATURATION WILL MEAN HEAVY SNOW RATES AT
TIMES. IT WILL BE DIFFICULT TO MEASURE SNOW...BUT ALL MODEL/HPC
AND SREF PLUME DIAGRAM GUIDANCE INDICATES THAT THE HEAVIEST SNOW
BAND WILL FALL FROM NEAR JMS-GFK-WASKISH...WHERE A BAND OF 9-16 INCHES
IS POSSIBLE. TO THE NORTH AND SOUTH OF THIS...EXPECT THE POTENTIAL
FOR 5-8 INCHES. LOCALLY HIGHER AMOUNTS MAY OCCUR IF BANDING OF SNOW
GETS GOING SUNDAY...WHICH IS POSSIBLE WITH A MID LEVEL DEFORMATION
BAND DEVELOPING NEAR THE 700MB LOW. THE ONLY THING THAT MAY CUT
DOWN ON SNOW AMOUNTS IN THE NORTH WOULD BE DRIER AIR ADVECTING
IN...BUT GIVEN THE LARGE AREA OF MID LEVEL WARM ADVECTION EVEN IN
THE NORTH...WE FEEL THIS WILL NOT BE THE CASE.

THE STORM WILL WIND DOWN MONDAY...BUT THERE WILL STILL BE BLOWING
AND DRIFTING EVEN MONDAY MORNING AND BITTERLY COLD WIND CHILLS.
SOME SORT OF HEADLINES WILL LIKELY BE NEEDED ON MONDAY MORNING AT
LEAST.

BY TUESDAY...THE BITTERLY COLD WEATHER WILL CONTINUE WITH A FRESH
SNOW PACK...AND LOWS COULD DROP TO 25-30 BELOW TUE MORNING.

&&

.AVIATION...
MAINLY VFR CIGS COULD FALL INTO THE MVFR RANGE ALONG WITH SOME
LIGHT SNOW IN THE NORTH TODAY.

&&

.FGF WATCHES/WARNINGS/ADVISORIES...
ND...BLIZZARD WATCH FROM SATURDAY EVENING THROUGH LATE SUNDAY NIGHT
     FOR NDZ006>008-014>016-024-026>030-038-039-049-052>054.

MN...BLIZZARD WATCH FROM SATURDAY EVENING THROUGH LATE SUNDAY NIGHT
     FOR MNZ001>005-007-008-013>015-022-027-029-030-040.

     WINTER STORM WATCH FROM SATURDAY EVENING THROUGH LATE SUNDAY
     NIGHT FOR MNZ006-009-016-017-023-024-028-031-032.

&&

DK

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GRAND FORKS ND
433 AM CST THU DEC 11 2008

MNZ001>009-013>017-022>024-027>032-040-NDZ006>008-014>016-024-
026>030-038-039-049-052>054-121045-
WEST POLK-NORMAN-CLAY-KITTSON-ROSEAU-LAKE OF THE WOODS-
WEST MARSHALL-EAST MARSHALL-NORTH BELTRAMI-PENNINGTON-RED LAKE-
EAST POLK-NORTH CLEARWATER-SOUTH BELTRAMI-MAHNOMEN-
SOUTH CLEARWATER-HUBBARD-WEST BECKER-EAST BECKER-WILKIN-
WEST OTTER TAIL-EAST OTTER TAIL-WADENA-GRANT-TOWNER-CAVALIER-
PEMBINA-BENSON-RAMSEY-EASTERN WALSH COUNTY-EDDY-NELSON-
GRAND FORKS-GRIGGS-STEELE-TRAILL-BARNES-CASS-RANSOM-SARGENT-
RICHLAND-WESTERN WALSH COUNTY-
433 AM CST THU DEC 11 2008

...MAJOR WINTER STORM EXPECTED THIS WEEKEND...

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EASTERN NORTH
DAKOTA...WEST CENTRAL AND NORTHWEST MINNESOTA.

.DAY ONE...TODAY AND TONIGHT

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

A POWERFUL STORM SYSTEM WILL DEVELOP IN THE CENTRAL PLAINS ON
SATURDAY...THEN TRACK INTO THE NORTHERN PLAINS ON SUNDAY. SNOW IS
LIKELY ACROSS ALL OF EASTERN NORTH DAKOTA AND WESTERN MINNESOTA
SATURDAY NIGHT AND SUNDAY. SNOW MAY BECOME HEAVY AT TIMES LATE
SATURDAY NIGHT THROUGH SUNDAY. IN ADDITION...STRONG NORTHERLY
WINDS MAY GUST OVER 40 MPH ON SUNDAY AND MAY PRODUCE BLIZZARD
CONDITIONS AT TIMES LATE SATURDAY NIGHT THROUGH SUNDAY NIGHT.
SIGNIFICANT SNOW ACCUMULATIONS ARE ALSO POSSIBLE...AND ROADS MAY
BECOME DRIFTED SHUT AND TRAVEL MAY BECOME IMPOSSIBLE LATE SATURDAY
NIGHT THROUGH SUNDAY NIGHT.

TEMPERATURES WILL ALSO FALL WELL BELOW ZERO BY SUNDAY NIGHT...AND
DANGEROUS WIND CHILLS FROM 25 TO 45 BELOW WILL RESULT. HIGH
TEMPERATURES ON MONDAY WILL REMAIN WELL BELOW ZERO...AND THE COLD
WEATHER WILL PERSIST NEXT WEEK.

THIS STORM HAS THE POTENTIAL TO SIGNIFICANTLY IMPACT TRAVEL ACROSS
ALL OF EASTERN NORTH DAKOTA...NORTHWEST AND WEST CENTRAL MINNESOTA
SATURDAY NIGHT THROUGH SUNDAY NIGHT. WHILE THE EXACT TRACK AND
EVOLUTION OF THIS STORM IS STILL SOMEWHAT UNCERTAIN...IT APPEARS
LIKELY THAT THE REGION WILL EXPERIENCE A POTENTIALLY LIFE THREATENING
STORM SATURDAY NIGHT THROUGH SUNDAY NIGHT.

PREPARE FOR THIS POTENTIALLY DANGEROUS STORM NOW AND TAKE THE
NECESSARY PRECAUTIONS TO PROTECT LIFE AND PROPERTY. STAY TUNED TO
LATER STATEMENTS ON THIS MAJOR WINTER STORM.

.SPOTTER INFORMATION STATEMENT...

SPOTTER REPORTS OF SNOWFALL AND VISIBILITY WILL BE APPRECIATED THIS
WEEKEND.

DK