349 FXUS63 KMPX 232216 AFDMPX Area Forecast Discussion National Weather Service Twin Cities/Chanhassen MN 416 PM CST Wed Jan 23 2019 .SHORT TERM...(This evening through Thursday night) Issued at 415 PM CST Wed Jan 23 2019 Forecast still remains on track for ground blizzard conditions to develop late tonight and tomorrow morning across portions of western and southern Minnesota. Our Arctic front is just now crossing the US/Canadian border into western North Dakota where gusts of 35 mph are already being reported. Expect the pressure gradient behind the front to tighten even further and wind speeds to increase as it approaches western Minnesota late tonight. This tightening gradient along with steep low- level lapse rates from intense cold air advection will allow for wind gusts as high as 40 to 45 mph for a few hours as the front passes. Calls to MNDOT officials and county emergency management suggests there is plenty of powdery snow left over from last weekend to blow around, so felt confident in extending the blizzard warning south to the Iowa border. Have included a winter weather advisory for blowing snow further east into portions of central and southeastern Minnesota, where winds will not quite reach blizzard criteria and the snowpack is not as fresh. Expect the worst conditions to begin late tonight across western Minnesota and during the overnight hours across southern Minnesota, with blizzard conditions expected to continue through mid-morning. Winds decrease somewhat into the afternoon, but will still be plenty high enough for visibility concerns to continue, though of lesser impact. Winds diminish Thursday evening into Friday morning along with the threat for blowing snow. Along with the blowing snow, temperatures will plummet behind the Arctic front along with dangerously cold wind chills Thursday morning into Friday. Temperatures will quickly drop below zero as the front passes, which along with the breezy winds will result in wind chill values dropping to -25 to -35 degrees by Thursday night. Temperatures drop even more Friday morning with -20s looking likely across portions of central Minnesota, but despite the frigid temperatures it looks like wind chill values will stay in the -25 to -35 range as wind speeds drop below 6-7 mph. .LONG TERM...(Friday through Wednesday) Issued at 415 PM CST Wed Jan 23 2019 Two concerns in the long term are the potential for a healthy snow Sunday night into Monday followed by just how cold is the arctic outbreak in its wake for next week going to be. This weekend will be cold, no question about that, though the core of the cold air, which comes in Thursday will be sliding off to our east for the weekend. So we'll be cold, but typical winter cold with highs of +5F to +10F and lows 10F to 15F below north of I-94 and 5F to 10F below south of I-94. Our pressure gradient all three days does not look overly strong, so winds will be fairly light through the weekend, which will keep wind chills from getting out of control, with peak cold values in the mornings ranging from around - 15F along the Iowa border, to around -30F in central MN. So we should not need any wind chill warnings, but will likely have some advisories every morning. For Sunday night and Monday, the GFS/ECMWF are in remarkably good agreement on a rather strong clipper impacting the region. This looks to have the potential to be an over achieving clipper, with a health swath of 6-10" of snow possible somewhere over southern MN into southern WI. The reason this has the potential to be a high end clipper is the route it takes. It will come out of northern Alberta Sunday morning, reaching southern/central Iowa Monday morning, where it will make a hard left and head nearly due east toward Detroit. This puts an inflection point over southern MN for the precipitation, resulting in a more prolonged event. Both the GFS/ECMWF lay down a strip of 0.5" to 0.6" of QPF with this system. When looking at the CIPs analogs, there's a similar system from the end of the December of 2000 where MSP got 7.5" of snow out of a mere 0.25" of liquid, so beside the longer duration snow, given how cold it will be, we are certainly looking at the potential for SLRs to be near or even exceeding 20:1, which would allow snow totals to overachieve quite a bit. The one variable that could throw a wrench in this forecast though is the cold and dry arctic high that will be centered just to the north of the Great Lakes that will be the source region for our near surface air parcels, so this dry air could limit how far east significant snow amounts make it. Winds don't look strong enough to meet blizzard criteria, but they will be strong enough to where we will have blowing and drifting issues as well, and with a big arctic high and strong cold advection following this snow, we could be blowing it around quite a bit in the days that follow. As for what comes next week, the ensembles and deterministic models are both pointing to our most significant surge of arctic air coming down for much of the week. Early indications are that this could be something that brings -20F type lows, even to MSP, with highs remaining well below zero. With that said, if you go back 7-10 days ago, the arctic outbreak coming to end this week was forecast to be colder than what we are expecting to see, with models moderating some on the cold as we got closer. Given the 23.12 ECMWF has an arctic outbreak that would end up being historic for next week, I would expect some moderation in the forecasts for next week in the coming days, but it will still be well below normal to end January, that we are confident in. && .AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon) Issued at 1204 PM CST Wed Jan 23 2019 Fog and stratus from this morning in western MN is burning off and it looks like it will not impact any MPX terminals this afternoon. Main issues this TAF period revolves around the powerful arctic front coming in this evening. There may be a brief snow shower with it, especially in eastern MN and western WI, but moisture is lacking and it does not look like we will see much, if any snow out of this. Very strong winds are expected, especially for the 4 hours or so after fropa, where gusts of 40-45 kts will be possible at AXN/RWF/MKT. This will lead to some blowing snow issues as well, but with no falling snow, we'll likely see limited vsby restrictions up at the ASOS vis sensor level. Once we work the post frontal stratocu field thru early Thu morning, should be sunny and windy the rest of the day. KMSP...Do not anticipate any low clouds at MSP until we go post frontal, which will not be until close to 6z. Some flurry/-sn potential between 8z and 12z is possible, but expect nothing worse than maybe a 15 minute burst where vis could get down to 2sm. Expect skies to clear out Thu morning some time between 10z and 16z. /OUTLOOK FOR KMSP/ FRI...VFR. Wind NW 5 kts. SAT...VFR. Wind W 5-10 kts SUN...MVFR/IFR with SN late. ESE at 10G20 kts && .MPX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...Winter Weather Advisory from 9 AM to 3 PM CST Thursday for MNZ041-047-048-054>057-064. Blizzard Warning from 9 PM this evening to 9 AM CST Thursday for MNZ041-047-048-054>057-064. Winter Weather Advisory from 9 PM this evening to 3 PM CST Thursday for MNZ042-049-058-066. Winter Weather Advisory from 9 AM to 6 PM CST Thursday for MNZ065-067-073>075-082-083-091-092. Blizzard Warning from midnight tonight to 9 AM CST Thursday for MNZ065-067-073>075-082-083-091-092. Winter Weather Advisory from midnight tonight to 6 PM CST Thursday for MNZ076>078-084-085-093. && $$ SHORT TERM...ETA LONG TERM...MPG AVIATION...MPG