Area Forecast Discussion
Issued by NWS Twin Cities, MN

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563
FXUS63 KMPX 121745
AFDMPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1145 AM CST FRI FEB 12 2016

.UPDATE...
ISSUED AT 1139 AM CST FRI FEB 12 2016

AVIATION DISCUSSION BELOW UPDATED FOR 18Z TAF ISSUANCE.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 415 AM CST FRI FEB 12 2016

THE SHORT TERM CONCERNS ARE CLOUD AND TEMPERATURE TRENDS TODAY
AND THE WIND CHILL THREAT TONIGHT.

WATER VAPOR IMAGERY SHOWING SHEARED VORTICITY WITH SOME DRYING NOTED
ACROSS NORTHERN MN INTO NORTHWEST WISCONSIN.  THIS APPEARS TO BE THE
LEADING EDGE OF THE CLEARING OVER THE NORTH/CENTRAL.  THERE DOES
APPEAR TO BE SOME LOWER STRATUS INTO CENTRAL MN THAT MAY YET
CONTAIN A FLURRY OR TWO.  WE SHOULD SEE CLEARING INTO THE EARLY
MORNING OVER THE ENTIRE REGION.  WINDS ARE EXPECTED TO PICK UP OVER
THE SOUTH AS WELL..AS THE COLDER ARCTIC AIR ARRIVES. WITH THE
LIGHT...FLUFFY SNOW OVER THE LAST COUPLE OF DAYS...WE SHOULD SEE AT
LEAST SOME PATCHY BLOWING SNOW.  IF WINDS GET STRONGER THAN
FORECAST...COULD SEE LOWER VSBYS INTO FAR SOUTH CENTRAL MN INTO THE
AFTERNOON.

THE WIND WILL GRADUALLY DIMINISH FROM WEST TO EAST TONIGHT AS THE
HIGH SETTLES IN OVER THE WEST.  TEMPERATURES SHOULD TUMBLE TO 15
BELOW TO 20 BELOW OVER A GOOD PORTION OF THE AREA.  THE WIND WILL
HOLD ON LONG ENOUGH TO WARRANT WIND CHILL ADVISORIES FOR READINGS
OF 25 BELOW TO 30 BELOW...MAINLY OVER WEST CENTRAL WISCONSIN AND
SOUTHERN MN.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 415 AM CST FRI FEB 12 2016

MAIN CONCERN FOR THE LONG TERM IS THE SYSTEM ARRIVING SATURDAY
NIGHT AND SUNDAY. TWO DISTURBANCES...ONE ALONG THE CANADIAN BORDER
AND THE OTHER TRACKING ALONG THE SODAK/NEB BORDER WILL GENERATE
WIDESPREAD SNOW ACROSS THE NORTHERN PLAINS BY SATURDAY AFTERNOON.
THIS SNOW WILL PROPAGATE EASTWARD INTO WEST CENTRAL MN BETWEEN
00-03Z SUNDAY AND TO THE WI BORDER BETWEEN 09-12Z SUNDAY. THE
SNOW WILL ENCOMPASS THE ENTIRE CWA SUNDAY MORNING BEFORE TAPERING
OFF SUNDAY AFTERNOON AS THE SOUTHERN DISTURBANCE ACCELERATES TO
THE SOUTHEAST AND FORCING WEAKENS QUICKLY.

BIGGEST CHANGE WAS A SLIGHT NORTHEASTWARD SHIFT IN THE HEAVIEST
SNOW AXIS WHICH ESSENTIALLY EXPANDED THE NORTHERN END OF THE 4-6
INCH RANGE NORTHEASTWARD TO ABOUT THE I-94 CORRIDOR. THIS SHIFT
LIKELY RESULTED FROM THE NORTHERN AND SOUTHERN DISTURBANCES
MAINTAINING A CONSTRUCTIVE RELATIONSHIP A BIT LONGER. IF THE
SOUTHERN WAVE ACCELERATES AND THE TWO BECOME DISJOINTED A BIT
QUICKER AMOUNTS MAY BE A BIT OVERDONE NORTHEAST OF I-94...SIMILAR
TO WHAT THE NAM IS ADVERTISING.

THERE MAY BE A PERIOD OF HEAVIER SNOW RATES FROM WEST CENTRAL TO
SOUTH CENTRAL MN LATE SATURDAY NIGHT WHEN THE BEST FORCING AND
DEEPEST MOISTURE COINCIDE. GFS AND ECMWF HAVE AS MUCH AS 1/4 INCH
QPF IN A 6 HOUR PERIOD WHICH WOULD EQUATE TO ABOUT 3 OR 4 INCHES
OF SNOW WITH A 15-20:1 SNOW RATIO. RATES SHOULD GRADUALLY SUBSIDE
AS FORCING WANES LATER SUNDAY MORNING.

TOTAL ACCUMULATIONS ARE NOW KNOCKING ON THE DOOR OF WARNING
CRITERIA IN PARTS OF MINNESOTA...PARTICULARLY ALONG THE MN RIVER.
HOWEVER...THIS SNOW SHOULD BE FALLING DURING A LOW IMPACT TRAVEL
TIME AND THERE ARE CURRENTLY NO MODEL SOLUTIONS THAT ARE
FORECASTING 6+ INCHES. THEREFORE...FEEL THERE IS NOT A NEED FOR A
WINTER STORM WATCH ATTM AND THIS EVENT WILL LIKELY BE HANDLED WELL
WITH AN ADVISORY. CANNOT SAY THERE IS ZERO CHANCE FOR 6+ INCH
TOTALS IN PLACES WITH THE POTENTIAL FOR BANDING TO PERSIST IN
AREAS...BUT THAT ASSESSMENT IS BEST DONE AS HIGHER RES GUIDANCE
BEGINS TO CAPTURE THE EVENT.

BEYOND SUNDAY THE ACTIVE NORTHWEST FLOW WILL CONTINUE THROUGH THE
REST OF THE PERIOD. MODELS HAVE NOT BEEN CONSISTENT WITH THE
STRENGTH NOR TIMING OF EACH OF THESE WEAK WAVES...SO CHC POPS
CONTINUE FOR SEVERAL PERIODS NEXT WEEK.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1139 AM CST FRI FEB 12 2016

GENERALLY CLEAR SKIES FOR THE PERIOD. WINDS NW 10-15 GUSTING OVER
20 KNOTS THROUGH SUNSET...THEN DIMINISHING AND BECOMING LIGHT AND
VARIABLE OVERNIGHT...WHEN TEMPERATURES FALL WELL BELOW ZERO. WINDS
EVENTUALLY DEVELOP A SE COMPONENT LATE IN THE PERIOD
TOMORROW.

KMSP...NO CHANGE FROM MAIN DISCUSSION.

/OUTLOOK FOR KMSP/
SUN...MVFR/IFR WITH -SN LIKELY. WIND SSE 15 KT.
MON...MVFR/VFR CIGS. WIND W 10 KT.
TUE...MVFR/VFR WITH -SN POSSIBLE.  WIND NW 10 KT.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
WI...WIND CHILL ADVISORY FROM 6 PM THIS EVENING TO 8 AM CST SATURDAY
     FOR WIZ014>016-023>028.

MN...WIND CHILL ADVISORY FROM 6 PM THIS EVENING TO 8 AM CST SATURDAY
     FOR MNZ074>078-082>085-091>093.

&&

$$

UPDATE...SPD
SHORT TERM...DWE
LONG TERM...BORGHOFF
AVIATION...SPD



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