000 FXUS63 KMPX 270554 AAB AFDMPX Area Forecast Discussion...UPDATED National Weather Service Twin Cities/Chanhassen MN 1154 PM CST Sat Jan 26 2019 .SHORT TERM...(This evening through early Sunday) Issued at 300 PM CST Sat Jan 26 2019 Light snow has lingered over southern Minnesota and western Wisconsin as a shortwave passes over the region. Have seen some overachieving in snowfall amounts as the Arctic airmass has allowed the DGZ to lower close enough to the surface to tap into the shallow moisture. Behind this shortwave a narrow area of high pressure will slide overhead tonight. Clearing skies and relatively calm wind with the high will again allow for lows to drop to -20 degrees across parts of central Minnesota, and -10 to -20 across the rest of the area outside of the Twin Cities Metro. The lack of wind should keep apparent temperatures fairly close to the air temperature, but if wind speeds end up a few mph higher than forecast a few areas with wind chills of -25 to -30 degrees are not out of the question tomorrow morning. High pressure tonight will be short lived as a potent clipper dives out of the northern plains overnight. Accumulating is expected to begin as early as sunrise across far-western Minnesota, and overspread the area as the day goes on .LONG TERM...(Sunday through Saturday) Issued at 300 PM CST Sat Jan 26 2019 Accumulating snow followed by dangerously cold air. These ideas have not changed with the models today and have in fact been reinforced. The synoptic idea remains generally the same. A potent clipper low over western Saskatchewan province early Sunday morning will drop into the western Dakotas Sunday evening then into Iowa Monday morning before shifting into the Great Lakes by midday Monday. Strong lift plus multiple sources of moisture available to the system will effectively produce at least 6" of snow from Sunday afternoon through midday Monday over nearly the entire WFO MPX coverage area. Liquid QPF looks to be in the 0.40" to 0.50" range for the entire coverage area. Working with snow ratios in the 16:1 to 20:1, snowfall amounts of 5" to 9" should be fairly simple to be realized. With little shift in the models thru this morning and the start of the snow roughly 24 hours out, confidence has increased among our neighbors and us to upgrade the watches already in place to warnings for all but a handful of southwestern counties. If anything, snow amounts are marginally warning-worth in our far northern tier of counties in central MN but would not at all be surprised to see several 6+" amounts from Douglas over to Kanabec counties while confidence is much higher in 6-9" amounts over much of central thru east and southern MN into western WI with this system. This system will then eject out to the east during the day Monday. On its heels is a roughly 1044mb high pressure area which will also contain H85 air in the -35C to -40C range. Air this cold has not been seen in nearly 20 years. This airmass will shift into the Upper Mississippi River Valley Tuesday afternoon and remain in place through Thursday before some relative "warming" takes place for the end of the week. Wednesday morning lows and afternoon highs continue to be the coldest in the forecast. Morning lows for the WFO MPX area are still ranging -25F to -30F while highs run -10F to -20F. This is not factoring in wind chills. With NW winds in the 10-20mph range, wind chills will easily drop to -40F to -50F with some -50F to -60F possible even into central MN. Wind chills during the day on Wednesday will run -35F to -45F, dangerously cold no matter the time of day. The high pressure airmass will then slide off to the east which will allow highs to climb into the positive single digits on Friday then into the double digits above zero on Saturday. && .AVIATION...(For the 06Z TAFS through 06Z Sunday night) Issued at 1154 PM CST Sat Jan 26 2019 VFR tonight. Cigs will lower Sunday morning and snow will build in from the west Sunday afternoon. Expect a rapid deterioration of cigs and visibilities to IFR/LIFR shortly after the onset of the snow. KMSP...No concerns until mid afternoon Sunday with the arrival of the snow. Snow rates of an inch per hour are possible Sunday evening. /OUTLOOK FOR KMSP/ MON...MVFR/IFR with -SN early. Wind NE bcmg NW 10-15kts. TUE...VFR. Chc MVFR/BLSN. Wind NW 15G30kts. WED...VFR. Wind NW 10G20kts. && .MPX WATCHES/WARNINGS/ADVISORIES... WI...Winter Storm Warning from 3 PM Sunday to noon CST Monday for WIZ014>016-023>028. MN...Winter Storm Warning from 3 PM Sunday to 6 AM CST Monday for MNZ042>045-049>053-058>063-066>070-075>077-083>085-093. Winter Storm Warning from noon Sunday to 6 AM CST Monday for MNZ041-047-048-054>057-065. Winter Weather Advisory from noon Sunday to 6 AM CST Monday for MNZ064-073-074-082-091-092. Winter Storm Warning from 3 PM Sunday to noon CST Monday for MNZ078. && $$ SHORT TERM...ETA LONG TERM...JPC AVIATION...BORGHOFF