Area Forecast Discussion
Issued by NWS Twin Cities, MN

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000
FXUS63 KMPX 022322
AFDMPX

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

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 323 PM CST TUE FEB 2 2016

HEAVIER SNOW BANDS THAT DEVELOPED ACROSS IOWA EARLIER TODAY HAVE SET
UP ACROSS THE SW TO THE NE ACROSS SOUTHERN MN WHICH AFFECTED THE
TWIN CITIES METRO AREA SHORTLY AFTER 12 PM.  LOCALLY 3-5 INCHES OF
SNOW FELL IN THESE HEAVIER SNOWFALL BANDS...WITH HIGHER AMTS NEAR
THE IOWA BORDER AS OF 3 PM. SEVERAL FACTORS LED TO THE EXPANSION OF
THE HEAVIER SNOWFALL FURTHER TO THE NW THAN PREVIOUSLY THOUGH IN THE
INITIAL WINTER STORM. FIRST...A DRY SLOT WHICH WAS FORECAST TO MOVE
ACROSS IOWA...HAD MOVED AS FAR NORTH AS SC MN WHICH LED TO LOWER
AMTS SOUTH OF THE IOWA BORDER...AND LOCALLY HEAVIER AMTS NORTH OF
THE BORDER. STRONGER FRONTOGENESIS WAS EVIDENT IN THE 85-70H
LAYER...PLUS THE ADDED AFFECT OF A VERY DEEP DENDRITIC ZONE.

AS OF 3 PM...REGIONAL RADAR HAS SEEN A VERY STRONG SIGNAL THAT THE
HEAVIER SNOWFALL MAYBE A BIT FURTHER TO THE NW ACROSS SW TO EC MN.
HAVE ALREADY EXPANDED THE WINTER STORM WARNING TO ACCOMPANY THE
HEAVIER SNOWFALL AMOUNTS TO THE NW OF THE TWIN CITIES METRO AREA.
NOT UNTIL THE MAIN UPPER LOW MOVES INTO SOUTHERN WI LATER TONIGHT
DOES THESE HEAVIER BANDS OF SNOW BEGIN TO LESSEN...OR AT LEAST
DECREASE IN INTENSITY AS COLDER AIR MOVES IN AND THE DEPTH OF THE
DENDRITIC LAYER DECREASES. THERE MAYBE A SMALL AREA OF 12-18 INCHES
OF SNOW SOMEWHERE IN SOUTHERN MN WHERE THESE HEAVIER SNOWFALL
BANDS SET UP IN THE NEXT FEW HRS.

THE NEXT WINTER STORM PLAYER IS THE WIND SPEEDS WHICH ARE FORECAST
TO INCREASE BETWEEN NOW AND MIDNIGHT. THIS WILL SET THE STAGE FOR
WIDESPREAD BLOWING SNOW...ESPECIALLY IN OPEN COUNTIES SOUTH AND WEST
OF THE TWIN CITIES. EXPECT A SHARP DECREASE IN THE SNOWFALL AFTER
MIDNIGHT AS THE MAIN UPPER FORCING MOVES OUT OF THE REGION. LEFTOVER
LIGHT SNOW/FLURRIES WILL LIKELY CONTINUE THROUGH WEDNESDAY MORNING
FOR EC MN AND WC WI...BUT SNOWFALL AMOUNTS WILL BE MINIMAL. NO OTHER
CHANGES EXPECTED THRU WEDNESDAY AFTN...WITH A SLOW DECREASE IN THE
WIND SPEED TOWARD SUNSET.

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 323 PM CST TUE FEB 2 2016

MAIN CONCERN IN THE EXTENDED PERIOD IS THE ARCTIC FRONT THAT IS
FORECAST TO MOVE THROUGH THE REGION LATER THIS WEEKEND. THIS FRONT
WILL BRING VERY STRONG NORTHWEST WINDS...AND DEPENDING ON THE SNOW
PACK COULD LEAD TO SIGNIFICANT BLOWING AND DRIFTING IN WESTERN AND
SOUTHERN MN SUNDAY NIGHT INTO MONDAY. IN ADDITION...COLD TEMPERATURES
WILL FOLLOW FOR EARLY NEXT WEEK. MEANWHILE...A FEW WEAK DISTURBANCES
WILL BRING PERIODIC CHANCES FOR LIGHT PRECIPITATION. TEMPERATURES
ARE COLD ENOUGH WHERE THE MAJORITY OF IT SHOULD FALL AS SNOW...BUT
COULD SEE A WINTRY MIX ON THE SOUTHERN EDGE OF THE
PRECIPITATION...ESPECIALLY SATURDAY NIGHT INTO SUNDAY AHEAD OF THE
FRONT.

PRECIPITATION CHANCES ARE CENTERED AROUND THURSDAY
AFTERNOON...FRIDAY NIGHT...AND SATURDAY NIGHT THROUGH MONDAY. THIS
IS DO TO SEVERAL PV ANOMALIES EMBEDDED IN NORTHWEST FLOW MOVING
THROUGH THE REGION. QPF AMOUNTS WILL BE LIGHT. FORECAST SOUNDINGS
SHOW A POTENTIAL FOR A WINTRY MIX ON SATURDAY NIGHT INTO SUNDAY.

THE MOST SIGNIFICANT IMPACT POTENTIAL LIES AT THE END OF THE
FORECAST PERIOD. A SURGE OF ARCTIC AIR IS EXPECTED TO MOVE SOUTHWARD
ACROSS THE REGION. FORECAST SOUNDINGS OFF THE GFS SHOW WINDS 30 TO
40 MPH...WITH GUSTS NEAR 50 MPG BEGINNING SUNDAY AFTERNOON AND
LASTING OVERNIGHT. IN ADDITION...THE THERMAL PROFILE BECOMES
SATURATED IN THE DENDRITIC GROWTH ZONE...AND ALTHOUGH THERE IS NOT
MUCH OMEGA THIS WOULD STILL FAVOR LIGHT SNOW...AND THE POTENTIAL FOR
WHITEOUT CONDITIONS GIVEN THE AFOREMENTIONED WINDS. THE EXTEND OF
THE BLOWING SNOW WILL DEPEND MOST HEAVILY ON THE CONDITION OF THE
SNOW PACK.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 515 PM CST TUE FEB 2 2016

INCREASING CONFIDENCE THAT A NARROW BAND /25NM WIDE/ OF MODERATE
TO OCCASIONALLY HEAVY SNOW WILL OCCUR FROM A SW TO NE LINE FROM NEAR
KULM TO KLVN TO KRNH IN THE NEXT 2 TO 3 HRS.

DUE TO THE PERSISTENT SLOW MOVEMENT OF THE UPPER LOW MOVING NE
ACROSS FAR SW IOWA...THIS SHOULD CONTINUE TO ENHANCE THE NARROW
BAND OF SNOW IN SOUTHERN MN/WC WI EARLY THIS EVENING BEFORE THE
MAIN UPPER LOW MOVES OFF INTO SOUTHERN WISCONSIN LATER TONIGHT.
OUTSIDE THIS NARROW BAND OF HEAVIER SNOW...SFC OBS ACROSS
SOUTHERN MN HAVE AVERAGED BETWEEN 3/4SM TO 3 SM IN -SN OR
BLSN....WHICH SHOULD CONTINUE THRU 6Z. VSBYS AS LOW AS 1/4SM WILL
OCCUR UNDER THE BAND MENTIONED FOR THE NEXT 2-3 HRS.
OTHERWISE...WINDS WILL INCREASE THIS EVENING FROM THE N/NE WITH
GUSTS OVER 30 KTS IN SW/SC AND PARTS OF EC MN. THESE WINDS WILL
ALSO CONTINUE TO GUST...AT LEAST ABV 25 KTS ON WEDNESDAY LEADING
TO ADDITIONAL BLSN AT TIMES.

KMSP...

HIGH CONFIDENCE THAT AT LEAST FOR THE NEXT 2-3 HRS...VSBYS WILL
AVERAGE NEAR 3/4SM TO 1SM IN -SN/BLSN. AFT 3Z...CONFIDENCE
DECREASES AS TO WHETHER ANOTHER BAND OF HEAVIER SNOWFALL MOVES
ACROSS THE AIRPORT GROUNDS. WIND SPEEDS WILL ALSO INCREASE...WITH
SUSTAINED WINDS OF 20-25 KTS...AND GUSTS ABV 30 KTS AT TIMES UNTIL
6Z. EXPECT A GRADUAL DECREASE IN THE -SN BY 6Z...WITH MAINLY BLSN
AFFECTING VSBY FOR THE REMAINDER OF THE TAF PERIOD. LIFR/IFR CIGS
WILL RISE TO MVFR OVERNIGHT AND BECOME VFR WEDNESDAY AFTN.

/OUTLOOK FOR KMSP/

THU...MAINLY VFR. SLGT CHC MVFR/-SN. WIND SW 5-10 KTS BCMG WNW.
FRI...MAINLY VFR. SLGT CHC MVFR/-SN. WIND SW 5-10 KTS.
SAT...MAINLY VFR. WIND SW/S 5 TO 10 KTS.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
WI...WINTER STORM WARNING UNTIL 6 AM CST WEDNESDAY FOR WIZ014>016-
     023>028.

MN...WINTER STORM WARNING UNTIL 6 AM CST WEDNESDAY FOR MNZ053-059>063-
     065>070-075>078.

     WINTER WEATHER ADVISORY UNTIL 6 AM CST WEDNESDAY FOR MNZ044-045-
     049>052-054>058-064.

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

&&

$$

SHORT TERM...JLT
LONG TERM...JRB
AVIATION...JLT


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