650 
FXUS63 KMPX 311126
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
525 AM CST TUE DEC 31 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 342 AM CST TUE DEC 31 2013

FORECAST CONCERN NEAR TERM IS SNOW THREAT OVER THE FAR SOUTH DURING 
THE DAY...AND WIND CHILLS THIS MORNING. PATCHWORK OF CLOUDS 
AFFECTING TEMPERATURES THIS MORNING.  

SOME MID CLOUD WORKING TO THE EAST...BUT APPEARS TO BE A SMALL 
AREA...AND CLEARING AGAIN TO THE NORTHWEST.  TEMPERATURES 15-20 
BELOW IN THE CLEAR AREA WITH WIND CHILLS FLIRTING WITH 35 BELOW.  
WILL LEAVE WIND CHILL ADV ALONE FOR NOW.  IT EXPIRES AT NOON WHICH 
IS OK.  

THE NEXT SHOT OF SNOW WILL WORK ACROSS FAR SOUTHERN MN DURING THE 
DAY.  SNOW TOTALS OF 2-3 INCHES A LIKELIHOOD ALONG INTERSTATE 
90.  WILL MENTION ADV HERE DURING THE DAY.  COLLABORATED WITH 
ARX/FSD/DMX FOR LOCATION/TIMING.  CLOUDS WILL BE A THREAT INTO 
TONIGHT AS WELL...AS THIS SYSTEM EXITS TO THE SOUTHEAST.  BOUNDARY 
LAYER REMAINS NEARLY SATURATED INTO TONIGHT ACROSS THE SOUTHWEST CWA 
AS WELL...AND MAY CONTINUE FLURRIES OVERNIGHT.  WILL HOLD ONTO 
CHANCE POPS FOR THIS THREAT FOR NOW. CLOUDS APPEAR THINNEST TO THE 
FAR NORTHEAST CWA OVERNIGHT...AND WILL LIKELY SEE LOWS 15-20 BELOW 
THERE ONCE AGAIN.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 342 AM CST TUE DEC 31 2013

THE NEW YEAR LOOKS TO RING IN AS 2013 ENDED...WITH SEASONABLY COLD 
AIR AND STRONG NORTHWEST WINDS BRINGING WINTER WEATHER FOR THE FIRST 
WEEKEND OF 2014. THE MAIN CONCERN IS THE STRENGTH OF THE WIND 
SATURDAY MORNING...AS WELL AT THE POTENTIAL FOR ADDITIONAL FALLING 
SNOW. ANOTHER SURGE OF ARCTIC AIR CONSUMES THE UPPER MIDWEST EARLY 
NEXT WEEK...WITH LOW TEMPS FALLING BELOW -20F. 

AT THE START OF THE PERIOD A BAND OF FRONTOGENETICALLY DRIVEN 
SNOWFALL SHOULD BE ONGOING TO THE SOUTH ACROSS IOWA...BUT HAVE 
FLURRIES FOR THE CWA SINCE A FEW FLAKES MAY BE FALLING OUT OF THE 
SKY. HIGH PRESSURE WILL BUILD IN ON THURSDAY KEEPING THE REGION DRY. 
THE NEXT CHANCE FOR SNOW WILL BE THURSDAY NIGHT INTO FRIDAY MORNING 
AS H850 THETA_E ADVECTION SPREADS ACROSS THE UPPER MIDWEST AHEAD OF 
THE NEXT UPPER LEVEL SHORTWAVE. FORECAST SOUNDINGS SHOW TREMENDOUS LOW 
LEVEL DRY AIR...AND HENCE THE MODELS FAIL TO GENERATE MUCH IN THE 
WAY OF QPF. HOWEVER OVER TIME THIS DRY AIR WILL SATURATE...SO FEEL 
THAT AT LEAST 20 TO 30 PERCENT CHANCE OF POPS IS WARRANTED AT THIS 
TIME. 

THE REAL CHALLENGE IS THE WEEKEND FORECAST. MONDAYS SNOWFALL DROPPED 
1-2 INCHES OF LIGHT FLUFFY SNOW ACROSS THE REGION. THIS SNOW IS NOT 
EXPECTED TO MELT OR SETTLE WITH TEMPERATURES CONTINUING ON THE COOL 
SIDE. ANOTHER ROUND OF LIGHT SNOW IS EXPECTED ALONG THE I-90 
CORRIDOR TODAY. THE 31.00Z GFS AND EC ARE IN GOOD AGREEMENT WITH THE 
PLACEMENT OF THE AFOREMENTIONED SHORTWAVE OVER PUGET SOUND BY 06Z 
FRIDAY. HOWEVER...BY 06Z SATURDAY THE EC BREAKS OFF A NORTHERN 
SHORTWAVE AND RACES IT ACROSS NORTHERN MINNESOTA. MEANWHILE THE GFS 
IS SLOWER AND FARTHER SOUTH WITH THE SHORTWAVE...SO IT LAGS THE MAIN
PV ANOMALY ACROSS THE DAKOTAS. AT THIS TIME IN THE FORECAST...THE
EC HAS A 990 LOW OVER THE BOUNDARY WATERS...WHILE THE HAS MORE
OF A BROAD 1004MB TROUGH ACROSS THE STATE OF MINNESOTA. 

WITH THE UPPER LEVEL FORCING OF THE SHORTWAVE STILL UPSTREAM IN
THE GFS SOLUTION...IT IS ABLE TO GENERATE 4-6 INCHES OF SNOW FROM
CANBY MN UP THROUGH DULUTH...BUT THE EC IS NEARLY VERTICALLY
STACKED...SO IT ONLY MANAGES TO PRODUCE JUST A DUSTING OF SNOW.
HOWEVER...THE EC IS MORE COMPACT WITH STRONGER COLD AIR
ADVECTION...WHICH MEANS VERY STRONG NORTHWEST WINDS AND POTENTIAL
BLIZZARD CONDITIONS ACROSS THE MINNESOTA RIVER VALLEY. THE 0-500M
MIXED LAYER WINDS OFF THE EC VALID AT 12Z SATURDAY HAS A BROAD
AREA OF 35KTS...WITH A SMALL AREA OF 40TS. THIS IS SIMILAR TO WHAT
THE EC WAS SHOWING WITH THIS PAST WEEKENDS SURGE OF ARCTIC AIR
THAT MANAGED TO PRODUCE WIDESPREAD 40-45MPH GUSTS...WITH ISOLATED
50MPH GUSTS. HOWEVER THIS TIME THERE WILL BE PLENTY OF FLUFFY
SNOW TO BLOW AROUND. JUMPING BACK TO THE GFS...IT HAS A SMALLER
AREA OF 35KT MIXED LAYER WINDS POSITIONED FARTHER WEST...AND
FAILS TO PRODUCE AND 40KT MIXED LAYER WINDS. BUT REMEMBER THE GFS
WAS GENERATING SIGNIFICANTLY MORE PRECIP...WHICH WOULD AID IN
BLOWING SNOW POTENTIAL.

LONG STORY SHORT...THERE WILL BE BLOWING SNOW THIS COMING WEEKEND 
ACROSS WESTERN MINNESOTA. TO WHAT DEGREE REMAINS UNCERTAIN DUE TO 
1)THE STRENGTH OF THE WINDS...AND 2)THE EXPECTED SNOWFALL. IT WILL 
BECOME MORE CLEAR WHEN THIS EVENT FALLS INTO THE FORECAST WINDOW OF 
THE NAM...WHICH OFTEN DOES VERY WILL WITH MODELING THE BOUNDARY 
LAYER WINDS IN THESE COLD AIR ADVECTION REGIMES. SPEAKING OF COLD 
AIR...WENT WELL BELOW GUIDANCE WITH -20 TO -25 FOR LOWS SUNDAY NIGHT 
AND MONDAY NIGHT. THE RAW MODEL OUTPUT OFF THE EC HAS H850 TEMPS OF 
-30 ACROSS THE BOARD. OF COURSE THIS DEPENDS ON IF THE EC IS ACCURATE 
WITH THE RAPID INTENSIFICATION OF THE STORM ALONG THE EAST 
COAST...BUT GIVEN THE RECENT LOW TEMPERATURE TRENDS FEEL CONFIDENT 
THAT THESE OVERNIGHT LOWS ARE WELL WITHIN THE REALM OF POSSIBILITY.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 509 AM CST TUE DEC 31 2013

SOME MID CLOUD MOVING IN RAPIDLY FROM THE WEST THIS MORNING...AHEAD
OF SHORT WAVE WHICH WILL SPREAD SOME LOW CIGS/VSBSYS ACROSS THE
KRWF AREA TODAY. THE REMAINDER OF THE AREA WILL REMAIN VFR...WITH
CIGS DROPPING TO 4-5 K FEET ALONG RIDGE AXIS BY MIDDAY OVER MN
AREA. CLOUDS SHOULD REMAIN THROUGH THE NIGHT WITH SOME THREAT OF
LIGHT SNOW OF FLURRIES MOVING BACK INTO WESTERN AREAS AFTER
06Z.01. WILL LEAVE VFR FOR NOW. LIGHT NORTHWEST TO NORTHWEST WINDS
AHEAD OF HIGH PRESSURE RIDGE TODAY...BECOMING MORE NORTHEAST
TONIGHT.

KMSP...MID CLOUDS MOVING IN EARLY. MAY LOWER TO 5-6 K FEET LATER
THIS MORNING BUT WILL REMAIN DRY. SOME THREAT OF IC EARLY WITH
COLD AIR AROUND...BUT STILL BELIEVE IT WILL REMAIN VFR. ANOTHER
SHOT OF LOWER CIGS POSSIBLE LATER TONIGHT INTO WED MORNING BUT
MEDIUM CONFIDENCE IT WILL REMAIN VFR. LIGHT WEST/NORTHWEST WIND
BECOMING NORTH/NORTHEAST THIS AFTERNOON/TONIGHT.

/OUTLOOK FOR KMSP/ 
WED...VFR. CHC MVFR/-SN. WINDS NE 5 TO 10 KTS. 
THU...VFR. WINDS NW 5 KTS. 
FRI...VFR. WINDS SSE 10-20 KTS.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WIND CHILL ADVISORY UNTIL NOON CST TODAY FOR MNZ047>053-055>063-
     065>070-075>078-083>085.

     WIND CHILL WARNING UNTIL NOON CST TODAY FOR MNZ041>045.

     WINTER WEATHER ADVISORY UNTIL 7 PM CST THIS EVENING FOR 
     MNZ082>084-091>093.

WI...WIND CHILL ADVISORY UNTIL NOON CST TODAY FOR WIZ014>016-023>028.

&&

$$

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