498 
FXUS63 KMPX 281155
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
555 AM CST SAT DEC 28 2013

.UPDATED FOR 12Z AVIATION DISCUSSION... 
ISSUED AT 544 AM CST SAT DEC 28 2013

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 421 AM CST SAT DEC 28 2013

POWERFUL ARCTIC BLAST REMAINS ON TRACK TO MOVE ACROSS THE REGION 
LATER TODAY. THIS WILL PRODUCE BLIZZARD CONDITIONS IN WESTERN MN. 
FARTHER EAST THE WINDS WONT BE QUITE AS SEVERE...BUT BY SUNDAY 
MORNING THE SUBZERO TEMPS WILL BE SPREADING ACROSS THE REGION AS THE 
COLDEST AIR OF THE SEASON BECOMES ENTRENCHED OVER THE UPPER MIDWEST.

THE DRIVING FORCE BEHIND THIS INCREDIBLE STORM SYSTEM STEMS FROM A 
SHORTWAVE THAT AS OF THIS MORNING WAS LOCATED OVER MONTANA. FARTHER 
UPSTREAM ANOTHER PV ANOMALY WAS LOCATED OVER NORTHERN ALBERTA ON THE 
PERIPHERY OF THE POLAR VORTEX. CONTINUOUS LEE SIDE WARMING ACROSS 
THE NORTHERN US...COMBINED WITH COLD AIR ADVECTION FROM THE NORTH 
IN CANADA LED TO AN IMPRESSIVE EAST/WEST TEMPERATURE GRADIENT 
EVIDENT BY THE 28.00Z RAOB MEASUREMENTS OF +11C AND +10C H850
TEMPS AT GREAT FALLS AND GLASGOW MT...WITH -11C JUST UP THE ROAD
IN EDMONTON CANADA. AT THE SURFACE A 1006MB LOW WAS LOCATED ALONG
THE ND/MT BORDER...WITH A COLD FRONT EXTENDING SOUTHWEST...AND AN
AREA OF HIGH PRESSURE BUILDING OVER ALBERTA. THE COMBINATION OF
THE TIGHT PRESSURE GRADIENT BETWEEN THE LOW AND HIGH...TOGETHER
WITH THE TREMENDOUS COLD AIR ADVECTION ALONG THE AFOREMENTIONED
TEMPERATURE GRADIENT IS THE REASON THAT SITES IN SOUTHERN CANADA
HAD GUSTED AS HIGH AS 53KTS AS OF 4AM SATURDAY MORNING.

THIS POTENT SYSTEM WILL TAKE THE CLASSIC ALBERTA CLIPPER TRACK...AND 
SLIDE SOUTHEASTWARD TODAY BEFORE CURVING NORTHEAST TOWARD THE GREAT 
LAKES LATER TONIGHT. ALTHOUGH THE SURFACE PRESSURE WILL NEVER GO 
BELOW 1005MB...THE IMPACTS FROM THIS ARGUABLY INNOCUOUS SURFACE LOW 
WILL BE FAR FROM UNNOTICEABLE. THE 28.00 500M MIXED LAYER WINDS OFF
THE GFS/ECMWF/NAM ARE IN EXCELLENT AGREEMENT THAT A CORE OF +35KT
MIXED LAYER WINDS WILL DIVE ALONG THE SOUTHWEST SIDE OF THE
MINNESOTA RIVER VALLEY THIS EVENING. BUFR FORECAST SOUNDINGS OF
THE NAM SHOW 6-8HRS OF 40KTS ATOP THE MIXED LAYER. THE COMBINATION
OF THE STRONG SYNOPTIC FORCING VIA THE PRESSURE RISE/FALL
COUPLET...TOGETHER WITH THE THERMODYNAMIC SUPPORT OF COLD AIR
ADVECTION AND CONTINUAL BOUNDARY LAYER DESTABILIZATION...SHOULD
ALLOW THE SURFACE TO REALIZE THESE STRONG WINDS ALOFT. DESPITE THE
RELATIVE WARM UP THESE LAST 48HRS...BOTH THE MAGNITUDE AND
DURATION OF THESE STRONG WINDS SHOULD LEAD TO CONSIDERABLE BLOWING
AND DRIFTING WITH ANYWHERE FROM 6-10 INCHES OF SNOWDEPTH IN PLACE
ACROSS THE REGION. ALSO...DESPITE THE LACK OF NEW
SNOWFALL...BLIZZARD CONDITIONS SHOULD LEAD TO ROAD CLOSURES
OVERNIGHT ACROSS WEST CENTRAL MN. THE BOUNDARIES OF THE BLIZZARD
WARNING WERE GOVERNED BY THE WEAKER WINDS TO THE EAST...AND THE
WARMER TEMPERATURES...LESSER SNOWPACK...AND LOWER SNOWFALL
POTENTIAL TO THE SOUTH. WINDS WILL BE EQUALLY AS STRONG ALONG THE
I-90 CORRIDOR...WHICH WILL MAKE TRAVEL DIFFICULT. SPEAKING OF
SNOWFALL POTENTIAL...MID-LEVEL FGEN TOGETHER WITH 500MB
HEIGHTFALLS WILL SUPPORT UPWARD VERTICAL MOTION. ALTHOUGH WEAK IN
NATURE...AS THE TEMPERATURE PROFILE COOLS...DEEP SATURATION IN THE
DENDRITIC GROWTH ZONE SHOULD LEAD TO EFFICIENT ICE CRYSTAL
GROWTH...SO EXPECT A FEW SNOW SHOWERS TO COMPOUND THE EFFECT OF
THE BLOWING SNOW. IF ONE WOULD BE ABLE TO MEASURE THE SNOW...THE
LIKELY WOULD NOT MEASURE MORE THAN A HALF INCH. THE WINDS WILL
TAPER OFF ON SUNDAY AFTERNOON TO AROUND 15-20KTS...BUT THE COLD
AIR WILL CONTINUE INTO EARLY NEXT WEEK.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 421 AM CST SAT DEC 28 2013

LONGER TERM HAS THE AREA IN THE DEEP FREEZE LINGERING THROUGH
THURSDAY IT APPEARS. MODELS HAVING DIFFICULTY IN TIMING OF ANY
REAL WEAK CLIPPER SYSTEMS IN THE NORTHWEST FLOW ACROSS THE AREA
DURING THIS PERIOD. THE GFS AND ECMWF DID COME BACK WITH A DECENT
SIGNAL FOR A CLIPPER MOVING THROUGH THE AREA MONDAY/MONDAY NIGHT.
COLLABORATION DID YIELD AN INCREASE IN POPS TO LIKELIES FOR THIS
ACROSS THE SOUTHERN CWA FOR NOW. THIS SHOULD PRODUCE AT LEAST SOME
LIGHT ACCUMULATION WITH HIGH SLR'S OF AT LEAST 20:1 INDICATED. THE
COLDEST STRETCH OF WEATHER APPEARS TO BE MONDAY NIGHT INTO TUESDAY
NIGHT. MUCH OF THE AREA SHOULD REMAIN BELOW ZERO AS THE COLD HIGH
DROPS SOUTHEAST.  OF COURSE OVERNIGHT LOW TEMPERATURES WILL BE
DEPENDENT ON SKY COVER. IT DOES APPEAR THE NORTHEAST CWA WILL BE
IN THE MOST FAVORABLE ARE FOR THE EXTREME COLD DURING THIS PERIOD.

MODELS CONTINUE TO TREND OVERALL MODERATION IN THE COLD AFTER
WEDNESDAY. UPPER FLOW BECOME MORE PROGRESSIVE WITH SOME RIDING
ALOFT AS THE EASTERN CONUS TROUGH EXITS TO THE EAST.  WILL HAVE TO
MONITOR THIS FOR OVERALL DEVELOPMENT. INCREASE THREAT OF A
STRONGER CLIPPER SYSTEM POSSIBLE LATE IN THE WEAK AS THE WARMER AIR
TRIES TO RETURN TO THE AREA.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 544 AM CST SAT DEC 28 2013

AREA OF LIVR/VLIFR FOG CONTINUES TO FESTER ALONG AND NORTH OF
I-94. CONDITIONS WILL BE SLOW TO IMPROVE AT THE WISCONSIN
LOCATIONS. LATER TODAY A POWERFUL COLD FRONT WILL MOVE THROUGH THE
REGION...WITH NORTHWESTERLY WINDS GUSTING NEAR 40KTS AT
TIMES...ESPECIALLY AT KAXN AND KRWF. BLOWING SNOW WILL CAUSE VISBYS
WILL DROP DOWN OVERNIGHT...BUT WINDS WILL LIGHTEN UP ON SUNDAY.

KMSP...
ANOTHER LOW CONFIDENCE FORECAST IN REGARDS TO THE FOG THIS
MORNING. CONDITIONS SEEM TO BE IMPROVING SOUTH AND EAST OF THE
METRO...BUT WILL HOLD ON TO THE LOWER VISBYS FOR A COUPLE MORE
HOURS. A BRIEF WINDOW OF LIGHT FREEZING DRIZZLE IS POSSIBLE AS THE
COLD FRONT MOVES THROUGH. BEHIND THIS FRONT WINDS WILL
INCREASE...AND TEMPERATURES WILL FALL SHARPLY WHICH WILL QUICKLY
FREEZE ANY PUDDLES OR WET SURFACES. CIGS SHOULD BE ABOVE 1700FT BY
SUNDAY MORNING. 

/OUTLOOK FOR KMSP/
SUN...MVFR EARLY...THEN VFR. WINDS NW AT 15G20KTS. TEMPS NEAR ZERO.
MON...VFR WITH MVFR/IFR -SN POSSIBLE LATE. WINDS SSE AT 10G15KTS. 
TUE...VFR WITH MVFR AND -SN POSSIBLE. WINDS NE AT 10KTS.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 PM CST 
     SUNDAY FOR MNZ042>045-049>053-058>063-066>070-075>078-
     083>085-091>093.

     BLIZZARD WARNING FROM 3 PM THIS AFTERNOON TO NOON CST SUNDAY FOR 
     MNZ041-047-048-054>057-064-065-073-074-082.

     DENSE FOG ADVISORY UNTIL 10 AM CST THIS MORNING FOR MNZ049-
     051>053-058>063-066-068>070.

WI...DENSE FOG ADVISORY UNTIL 10 AM CST THIS MORNING FOR WIZ014>016-
     023>028.

&&

$$

SHORT TERM...JRB
LONG TERM...DWE
AVIATION...JRB