887 FXUS63 KDLH 201151 AFDDLH Area Forecast Discussion National Weather Service Duluth MN 551 AM CST Sat Jan 20 2018 .UPDATE... Issued at 540 AM CST Sat Jan 20 2018 Updated for the 12z Aviation Discussion below. && .SHORT TERM...(Today through Sunday) Issued at 341 AM CST Sat Jan 20 2018 The short-term forecast is looking mostly dry through the day Sunday. This morning, a cold front was draped along the International Border, which has brought some low clouds over our northern counties. However, very little, if any, precipitation was observed on DLH radar. In fact, very little in the way of radar returns were seen in southwest Ontario Canada. There were some returns seen up by Dryden, Ontario Canada, but that was about all that was observed. There may be some flurries near International Falls and Kabetogama before sunrise this morning. The main highlight for this morning will be fog, especially from the Brainerd Lakes, east towards Hibbing and Hayward. As of 09z this morning, visibilities in these areas have already dropped to as low as 1/4 miles at BRD and 3/4 miles at HYR. Trapped moisture in the boundary layer due to recent melting snow, underneath a strong inversion, appears to have led to this morning fog, and the latest high-res guidance indicates this fog could continue through the morning hours, and even expand, before temperatures start to increase this afternoon. Skies will be partly to mostly cloudy as low level clouds remain in place across the north, and some mid-level clouds will move across the south. Highs today will range from the lower 30s over the Arrowhead region to the middle to upper 30s elsewhere. Due to another day of above freezing temperatures for much of the Northland today, more fog will be possible tonight. The most robust potential for precipitation, albeit a small chance, will come tonight, and through the day Sunday, over northwest Wisconsin when some 850-700 mb layer warm air advection ahead of the next winter storm system will bring some light precipitation chances. Soundings indicate some fairly decent amount of dry air in the low-levels, so any precipitation that forms will have a tough time reaching the surface, but the RAP soundings indicate plenty of ice production aloft, so some ice crystals may melt through the warm layer on the way down. This could pave the way to snow early, transitioning to a rain/snow mix by the afternoon. Again, very little in the way of accumulations are expected. The more impactful weather will be Monday as the aforementioned winter storm approaches. More details below. .LONG TERM...(Sunday night through Friday) Issued at 341 AM CST Sat Jan 20 2018 The focus in the extended period remains on the winter storm that is still expected to impact much of northern Wisconsin into adjacent northeast/east central Minnesota Sunday night into Monday night. The models are in pretty good agreement on the mass fields but still differ on some of the details. The ECMWF has made a slight northward shift in track/QPF compared to the 12Z Friday model run. Surface low pressure is expected to move roughly from central Kansas Sunday evening to the eastern Iowa/southern Wisconsin/northern Illinois vicinity by Monday evening, then into Michigan by 12Z Tuesday. We used a blended approach to timing and QPF which mostly keeps the forecast on track. The precipitation is expected to move in slower Sunday night so we did delay the start time of the Winter Storm Watch to midnight Monday. As the low moves northeast Sunday night, light precipitation is expected to develop over portions of northern Wisconsin possibly into the Twin Ports and I-35 corridor. Saturation will be developing Sunday night so there may be a period of freezing drizzle that occurs before the better lift/deeper saturation develops late Sunday night into Monday. Snow will increase in intensity and coverage during the day Monday as the low pressure system lifts further north and FGEN continues over central/northern Wisconsin. The differences among the models deals mostly with how much and where the heaviest precipitation occurs. The GFS is highest with snow/QPF which is typical and the ECMWF is lighter but also has trended up some since its last run. As mentioned, we went with a blended approach and still have a swath of snowfall late Sunday night through Monday night of 6 to 10 inches from Burnett County northeast toward Hurley in Iron County. Snowfall tapers off quite rapidly north and west of a line from Pine City to Bayfield with the Twin Ports region expected to get 1 to 3 inches. There will likely be lake enhanced snowfall along much of the South Shore thanks to east to northeast winds that are expected to back to north late Monday night. An absence of colder air around 850mb will keep the lake contribution from becoming too high though. In addition to the snowfall will be gusty winds, which will cause some blowing and drifting. The wind will be strongest close to Lake Superior where gusts over 35 mph will be possible late Sunday night into Monday evening. Some adjustments in where the heaviest snow occurs and snow totals remain likely over the next 24-36 hours. Stay tuned for updates. The rest of the extended will feature a couple weaker systems that may bring a chance for precipitation, with the best chance occurring late in the week toward next weekend. Colder temperatures will move over the area behind the low Tuesday and Wednesday, with highs in the teens to lower twenties. Highs will then warm into the upper twenties to middle thirties by Friday. && .AVIATION...(For the 12Z TAFS through 12Z Sunday morning) Issued at 551 AM CST Sat Jan 20 2018 A complex aviation forecast on tap for today and tonight, with flight categories ranging from VFR, down to LIFR in some spots. A cold front has been draped across the International Border this morning, supporting MVFR stratus. Across our south, mid- to upper-level cirrus is building in. Between all of this, visibilities have plummeted due to fog where skies have cleared. Vsbys have dropped as low as 1/4 SM at KBRD and KHYR. Moisture trapped in the boundary layer underneath an inversion has led to this fog. The high-resolution model guidance has finally started to resolve this fog, having MVFR/IFR vsbys last through the morning hours, and generally improving through the afternoon. However, another night of fog will be possible again tonight, but some uncertainty does exist for just how low these visibilities will be. For now, tried to hint at the vsby reductions with some MVFR values, although some of the high-res guidance goes even lower than this in some spots. Confidence is just not there yet to go that low. MVFR cigs will also be possible in spots, especially overnight tonight. && .PRELIMINARY POINT TEMPS/POPS... DLH 35 23 31 21 / 0 10 10 30 INL 34 15 27 13 / 0 10 10 0 BRD 37 22 33 23 / 10 10 10 20 HYR 38 24 37 27 / 10 20 20 60 ASX 39 24 34 25 / 10 10 10 40 && .DLH WATCHES/WARNINGS/ADVISORIES... WI...Winter Storm Watch from late Sunday night through Monday evening for WIZ002>004-006>009. MN...None. LS...None. && $$ UPDATE...JTS SHORT TERM...JTS LONG TERM...Melde AVIATION...JTS