857 FXUS63 KMPX 032115 AFDMPX Area Forecast Discussion National Weather Service Twin Cities/Chanhassen MN 315 PM CST Sun Feb 3 2019 .SHORT TERM...(This evening through Monday night) Issued at 300 PM CST Sun Feb 3 2019 Tonight's forecast is highly dependent on surface and road temperatures as the predominate weather type tonight will be freezing drizzle or freezing rain. A weak surface low moved across southern Minnesota earlier today, with a subtle feature that led to colder air draining southeast across the Minnesota River Valley. This led to surface temperatures dropping below freezing as far east as south central Minnesota during the early afternoon. However, further to the north across the Twin Cities metro area and in west central Wisconsin, temperatures remained nearly steady as the slightly higher terrain kept the colder air from moving back to the north. In addition, winds were more from the north vs. the west where the colder air drained along the Minnesota River Valley. Further to the south across Iowa, temperatures rose into the 40s and 50s. This boundary to the south will be critical if a weak surface low moves from southeast South Dakota, northeast along the Minnesota/Iowa border. This will lead to the warmer air advecting back northward into southern Minnesota, mainly south of the Minnesota River Valley. Depending upon if the colder air holds in far southern Minnesota, west of I-35, will depend on whether drizzle, or freezing drizzle will start this evening. Confidence is higher near the Minnesota River Valley vs. along the border of Iowa on freezing precipitation developing. Further to the northeast across east central Minnesota, and west central Wisconsin, not until winds become more west/northwest later tonight will temperatures fall below freezing, and lead to freezing drizzle/freezing rain. Too many uncertainties in this forecast to deviate on the current Winter Weather Advisory. The atmospheric moisture will begin to moisten up this evening, and especially after midnight. This means the confidence is much higher on precipitation developing after midnight vs. this evening. The higher precipitation amounts will remain in south central Minnesota, and west central Wisconsin where locally one quarter of an inch is likely. Further to the west, amounts are highly dependent on when the atmosphere moistens up to allow for more rain vs. drizzle. After 12z, much drier/colder air will move across the region with temperatures falling through the morning. Wind chill values drop to near -25F in west central Minnesota during the day, but not enough to warrant a current Wind Chill Advisory. Otherwise, dry conditions will continue through Monday night. .LONG TERM...(Tuesday through Sunday) Issued at 245 PM CST Sun Feb 3 2019 An active weather pattern is expected this week along with below normal temperatures. A deep trough will remain over the Western CONUS through mid week before it begins shifting Eastward toward the Central CONUS Thursday into Friday. A shortwave and associated jet energy will bring chances for snow Tuesday afternoon into Wednesday. Warm air advection ahead of the wave will allow for the possibility of light snow starting Tuesday morning. There is also a slight chance for freezing drizzle as the system departs Wednesday morning with drying air aloft. The ECMWF continues to show less precipitation than the GFS, so kept QPF near the average, near 0.10- 0.15 inches with the possibility of 1-3 inches of snowfall accumulation in Southern MN. If the higher QPF does pan out, than there would be potential for areas of 4+ inches of snowfall. A Colorado Low is expected to develop on Wednesday and eject into the Central Plains and lift into Illinois while remaining vertically tilted. This will bring another round of snowfall for MN/WI, but it is still too early to say exact amounts, especially with continued model discrepancies. The ECMWF brings the surface low to Central IL at 00Z Friday, whereas the GFS has the surface low near Chicago by 12Z Thursday. Consensus indicates potential for near 0.25" of QPF and 4+ inches of snowfall by 00Z Friday. Cold air advection and upper level troughing will follow the Colorado Low with wind chills below -25 forecast for Thursday night and Friday in Western MN. Upper level ridging is progged to encompass the Central CONUS by Saturday, allowing for temperatures to moderate to near normal by Sunday. Both the ECMWF and GFS indicate potential for another Colorado Low-like system developing with potential for precipitation across the Midwest on Sunday. && .AVIATION...(For the 18Z TAFS through 18Z Monday afternoon) Issued at 1130 AM CST Sun Feb 3 2019 Recent airport observations have indicated that they are near or slightly below airport minimums as of 1130 AM, especially in west central Wisconsin where the dense fog continues. Elsewhere, cigs/vsbys will remain in the IFR or LIFR range through 00z, with little chance of precipitation. The best chance of precipitation occurs after 3z, with the most likely time frame between 6z and 15z Monday. KAXN has the best chance of all -SN, with KMKT-KMSP- KRNH having the best chance of -FZRA/-FZDZ during the overnight hours. KEAU should stay above freezing until the change over to -SN. Confidence is still fairly high that freezing precipitation will develop this evening in portions of southern/eastern Minnesota, and into west central Wisconsin. Lower confidence on the amount of freezing precipitation. After 12z, any freezing precipitation will change over to -SN or end. Cigs/Vsbys should begin to rise Monday morning with gusty northwest winds developing. KMSP... Main change to this TAF period is to hold onto the lower cigs/vsbys through the early afternoon, with an introduction of PROB30 after 3z. Confidence still remains high enough to hold onto the FZRA after 6z. /OUTLOOK FOR KMSP/ Mon Aftn...MVFR with -SHSN. Wind NW 15G25 kts. Tue...VFR/MVFR with IFR/-SN likely late. Wind N bcmg E 5 kts. Wed...MVFR chc IFR. Chc -SN in mrng. Wind NW 10G20 kts. && .MPX WATCHES/WARNINGS/ADVISORIES... WI...Winter Weather Advisory from 9 PM this evening to 9 AM CST Monday for WIZ014>016-023>025. MN...Winter Weather Advisory from 9 PM this evening to 9 AM CST Monday for MNZ042>045-049>053-057>063-065>070-073>078- 082>085-091>093. Dense Fog Advisory until midnight CST tonight for MNZ074>077- 082>085-091>093. && $$ SHORT TERM...JLT LONG TERM...AMK AVIATION...JLT