Area Forecast Discussion
Issued by NWS Twin Cities, MN

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632
FXUS63 KMPX 021010
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
410 AM CST TUE FEB 2 2016

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 410 AM CST TUE FEB 2 2016

SIGNIFICANT SNOW AND WIND ON TRACK TO IMPACT EASTERN AND SOUTHERN
AREAS OF THE FA TODAY AND TONIGHT. THE CULPRIT IS A LOW PRESSURE
STORM SYSTEM OVER THE SOUTHERN PLAINS EARLY THIS MORNING. THE
SURFACE LOW WILL HEAD NORTHEAST TODAY...REACHING EASTERN IA
TONIGHT AND THE WESTERN GREAT LAKES BY WEDNESDAY MORNING.

THE LEADING EDGE OF THE SNOW WAS JUST SOUTH OF MN EARLY THIS
MORNING. A STRONG BAND OF MID LEVEL FRONTOGENESIS WILL LIFT
NORTHEAST ACROSS THE EASTERN FA DURING THE LATE MORNING AND
AFTERNOON HOURS ACCOMPANIED BY LOW LEVEL WAA AND VERY IMPRESSIVE
DIFFERENTIAL DIVERGENCE. THIS WILL RESULT IN A BAND OF HEAVY
SNOW...WITH ACCUMULATIONS OF 1-2 INCHES PER HOUR...SPREADING FROM
SOUTH CENTRAL MN BY MID MORNING ON NORTHWARD THROUGH THE TWIN
CITIES AND WESTERN WI THIS AFTERNOON. THIS BAND OF HEAVY SNOW IS
WHERE TWO-THIRDS OF OUR TOTAL SNOW ACCUMULATION COMES FROM. THE
EVENING COMMUTE WILL BE A MESS. WHILE THIS IS OCCURRING...NORTHERLY
WINDS WILL BE ON THE INCREASE...WITH SPEEDS NEAR 30 MPH SUSTAINED
ACROSS SOUTH CENTRAL MN FROM LATE MORNING ONWARD. BUFKIT PROFILE
DATA CONTINUES TO SUPPORT GUSTS TO 45 MPH DURING THE LATE
AFTERNOON AND EVENING ACROSS SOUTH CENTRAL MN. SPEEDS FARTHER
NORTH WILL BE MORE IN THE 20 TO 25 MPH ALONG WITH CONSIDERABLE
BLOWING AND DRIFTING SNOW. THE SNOW WILL BEGIN TO DIMINISH AFTER
MIDNIGHT AND LIKELY BE OVER BEFORE DAYBREAK WEDNESDAY.

THE MAIN STICKING POINT WITH THIS SYSTEM REMAINS THE SNOW RATIOS.
THERE IS QUITE A DIFFERENCE BETWEEN COBB AND THE AIR FORCE METHOD.
USED VALUES CLOSER TO CLIMATOLOGY (13:1) WHICH WAS MORE OF A
MIDDLE GROUND BETWEEN THE TWO EXTREMES. IN THE END...VERY LITTLE
CHANGE WAS NOTED TO THE OVERALL TOTAL SNOWFALL FORECAST FROM THE
DAY SHIFT . WE STILL EXPECT BETWEEN 6 AND 12 INCHES IN THE
WARNING AREAS...WITH THE HIGH END AMOUNTS FROM FAIRMONT AND ALBERT
LEA ON NORTHEAST THROUGH RED WING TO NEAR EAU CLAIRE. THE TWIN
CITIES METRO IS IN THE 6 TO 8 INCH RANGE FROM NORTHWEST TO
SOUTHEAST. DUE TO A SLIGHT SHIFT NORTHWEST WITH THE QPF
OVERNIGHT...WE DID ADD ANOKA AND POLK COUNTIES TO THE WINTER STORM
WARNING AREA. IN ADDITION...WITH MORE SNOW EXPECTED FROM WEST
CENTRAL INTO CENTRAL MN...COUNTIES FROM LAC QUI PARLE THROUGH
STEARNS TO MILLE LACS AND KANABEC WERE ADDED TO THE WINTER
WEATHER ADVISORY. ALTHOUGH SNOW IN THESE AREAS WILL BE IN THE 2 TO
4 INCH RANGE...ITS THE WIND WITH BLOWING AND DRIFTING SNOW THAT
PROMPTED THE EXPANSION WESTWARD.

IN THE TEMPERATURE DEPARTMENT...YET ANOTHER MILD DAY ON TAP WITH
HIGHS IN THE UPPER 20S TO LOWER 30S. EVEN TONIGHT...LOWS ARE WELL
ABOVE SEASONAL VALUES WITH READINGS IN THE MIDDLE TEENS TO LOWER
20S FORECAST.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 410 AM CST TUE FEB 2 2016

THE HIGHLIGHTS OF THE LONG TERM PERIOD INCLUDE TWO WEAK SHORTWAVES
MOVING THROUGH LATER THIS WEEK...ZONAL FLOW ALLOWING TEMPERATURES TO
WARM THIS WEEKEND...AND THE ARCTIC AIR INTRUSION FOR EARLY NEXT WEEK
THAT THE GUIDANCE HAS CONSISTENTLY INDICATED.

BY DAYBREAK WEDNESDAY...THE SURFACE LOW WILL BE NEAR MILWAUKEE...AND
THE SYSTEM DECAYING AS IT MOVES NORTHEAST.  CYCLONIC CIRCULATION ON
THE BACK SIDE OF THE SYSTEM WILL PRODUCE LIGHT SNOW LINGERING AS FAR
WEST AS EASTERN MN.  NOTHING MORE THAN A DUSTING TO A FEW TENTHS OF
AN INCH WOULD COME OF ANY LINGERING SNOW AT THAT POINT.  WITH THE
SYSTEM EXITING THE REGION A TAD SLOWER...THE POPS WERE PULLED BACK
TO THE WEST 30 TO 50 MILES. WITH WINDS TURNING NORTHWESTERLY AND A
FRESH SNOW COVER ACROSS SOUTHERN MN THROUGH WEST CENTRAL WI...WENT
ON THE COOL SIDE OF THE GUIDANCE FOR TEMPERATURES TOMORROW AND
TOMORROW NIGHT.  WIDESPREAD SINGLE DIGIT LOWS ARE EXPECTED BY
THURSDAY MORNING...WITH SOME SUB-ZERO LOWS POSSIBLE ESPECIALLY IN
THE AREAS THAT RECEIVE THE MOST SNOW ON TUESDAY.

THURSDAY AND THURSDAY NIGHT...THE GFS AND THE ECMWF ARE IN GOOD
AGREEMENT ON A SHORTWAVE RACING SOUTHEAST THROUGH CANADA AND BRINING
LIGHT SNOW TO OUR REGION ON THURSDAY.  A DUSTING...TO A FEW TENTHS
OF SNOW LOOKS TO BE ALL THIS WAVE WOULD PRODUCE AS IT QUICKLY MOVES
THROUGH OUR AREA.

FOR FRIDAY...A STRONGER PV ANOMALY WILL FOLLOW A SIMILAR PATH
THROUGH CANADA AND MOVE THROUGH THE UPPER MIDWEST. THERE WONT BE A
LOT OF MOISTURE TO WORK WITH...BUT THIS WAVE COULD PRODUCE AN INCH
OF SNOW ACROSS A PORTION OF THE UPPER MIDWEST...EXACTLY WHERE IS
DIFFICULT TO SAY THIS FAR OUT IN TIME. CONTINUED TO INCLUDE LOW
END POPS ACROSS THE FORECAST AREA FOR THIS WAVE ON FRIDAY THROUGH
FRIDAY NIGHT.

AS FOR THE WEEKEND...THE GFS AND ECMWF ARE IN GOOD AGREEMENT ON THE
UPPER FLOW BECOMING ZONAL WHICH WILL ALLOW TEMEPRATURES TO RISE INTO
THE 30S FOR MUCH OF THE AREA...AS A LOW PRESSURE SYSTEM WORKS
ACROSS SOUTH CENTRAL CANADA...ENCOURAGING WARM AIR ADVECTION IN THE
LOW LEVELS ACROSS OUR AREA...WHICH IS WHY POPS COME BACK INTO THE
FORECAST FOR SUNDAY NIGHT INTO MONDAY MORNING.

ONCE THAT SYSTEM PASSES BY...THE UPPER PATTER QUICKLY BECOMES HIGHLY
AMPLIFIED WITH A DEEP LONGWAVE TROUGH OVERHEAD...AND STRONG
NORTHERLY FLOW...ALLOWING ARCTIC AIR TO POUR SOUTH INTO OUR REGION.
EXPECT NEXT WEEK TO BE COLDER THAN NORMAL GIVEN THE ARCTIC AIR
INTRUSION.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1100 PM CST MON FEB 1 2016

FOG AND LOW CEILINGS WILL MAKE FOR IFR-OR-WORSE CONDITIONS
OVERNIGHT INTO TOMORROW MORNING...IN ADVANCE OF THE SN/BLSN
EXPECTED FOR MUCH OF THE AREA TMRW INTO TMRW NIGHT. ONLY KAXN
LOOKS TO ESCAPE THE -SN...BEING TOO FAR DISPLACED FROM THE CURRENT
LOW PRES TRACK. HOWEVER...DID INCLUDE A PROB30 MENTION TO ACCOUNT
FOR A SMALL CHANCE OF -SN SHIFTING THAT FAR N LATE AFTN INTO THE
EVE...ALONG THE LINES OF THE WAY THE MODELS HAVE BEEN TRENDING
SINCE YESTERDAY. CEILINGS WILL LIKELY BE BOUNCING BETWEEN IFR AND
LOWER-END MVFR BEFORE THE -SN BEGINS. ONCE THE SNOW MOVES IN FROM
THE S...VSBYS WILL LIKELY DROP TO 1SM OR LESS IN SN/BLSN WHILE
CEILINGS DROP TO IFR LEVELS. WINDS FROM THE NE AND N WILL INCREASE
TO THE 15G25KT AREA BY MIDDAY TMRW...AND POTENTIALLY TO 20G30KT BY
TMRW EVE.

KMSP...SMALL VFR POCKETS HAVE EVOLVED AROUND KMSP LATE THIS
EVE...BUT THIS IS EXPECTED TO BE SHORT-LIVED AFTER 02/06Z
INITIALIZATION. LOWER-END MVFR CEILINGS /MAINLY BETWEEN 010-015
HEIGHTS/ WILL PREVAIL OVERNIGHT THEN SLIGHTLY RISE ABOVE 1700 FT
BY LATE TMRW MRNG AS THE -SN COMMENCES. CONDITIONS ARE EXPECTED TO
DETERIORATE RAPIDLY BY MIDDAY...WITH SOLID IFR CONDS LIKELY AND
POTENTIALLY INTO LIFR OR VLIFR SHOULD HEAVIER BANDS OF SNOW
DEVELOP AND/OR CEILINGS DROP FURTHER THAN CURRENTLY ADVERTISED.
SNOWFALL RATES OF 1 IN/HR CANNOT BE RULED OUT...ESPECIALLY DURG
THE AFTN HOURS AND POTENTIALLY HAVING SIGNIFICANT IMPACTS TO THE
AFTN/EVE PUSH.

/OUTLOOK FOR KMSP/
WED...VFR. WIND NW 10-15 KTS.
THU...VFR. WIND SW 5-10 KTS.
FRI...MAINLY VFR. SLGT CHC MVFR/-SN. WIND S 5-10 KTS.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
WI...WINTER STORM WARNING FROM 9 AM THIS MORNING TO 6 AM CST
     WEDNESDAY FOR WIZ014>016-023>028.

MN...WINTER STORM WARNING FROM 9 AM THIS MORNING TO 6 AM CST
     WEDNESDAY FOR MNZ060>063-067>070-075>078.

     WINTER WEATHER ADVISORY FROM 9 AM THIS MORNING TO 6 AM CST
     WEDNESDAY FOR MNZ044-045-049>059-064>066.

     BLIZZARD WARNING UNTIL 6 AM CST WEDNESDAY FOR MNZ073-074-082>085-
     091>093.

&&

$$

SHORT TERM...RAH
LONG TERM...SPD
AVIATION...JPC



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