163 FXUS63 KMQT 151001 AFDMQT Area Forecast Discussion National Weather Service Marquette MI 501 AM EST Wed Jan 15 2020 .SHORT TERM...(Today and tonight) Issued at 442 AM EST WED JAN 15 2020 Regional radar this morning shows plenty of returns across MN into northern WI as surface observations and webcams indicate little if any precipitation is reaching the ground so far. Latest RAP soundings show saturation and lift through the DGZ; however, indications of a rather deep subsidence inversion is present. Through the rest of the early morning, RAP suggests these soundings to saturate from above as -SN continues to fall through this layer. Even most of the returns along the WI border this morning are being seen from the DLH and GRB radar, approx 10kft above the ground. Lowest returns seen by MQT radar mirror the same thing so far. For today, a shortwave trough is progged to pass through Upper Michigan and bring widespread snow across the UP from west to east through the day. Aloft, this shortwave coincides with weak height falls, PVA, and a brief period of isentropic ascent. Further up, divergence from the exit region of a passing jet stream will assist in lift with weak FGEN setting up in the circulation below. The result will be widespread 1 to 2 inches, locally up to 3 inches by 00Z tonight, with the greatest amounts expected in Gogebic and Ontonagon counties and along the WI border. Behind the shortwave tonight, winds slowly become NW as 850mb temps fall into the teens blo zero. This will bring LES to the NW wind snow belts tonight. Early on, sfc and 925 winds don't quite line up with 850 winds, as 850 winds retain a more westerly component. Models suggest these winds to begin to align a few hours after 00Z tonight as influence from the passing shortwave exits east. As LES snow picks up, some CAMs suggest a few stronger bands to set up across the Keweenaw and then another across the east in Alger county after 6Z. With this, have trended slightly higher in QPF amounts, thus snow amounts for tonight by including the HREF and WRF models before smoothing out to account for spatial differences. The result is an additional 2 to 4 inches, locally up to 5 inches, of snow tonight across the NW wind LES belts. The highest amounts will be seen across the west with 2 to 3 inches expected east of Marquette as influence from the shortwave takes slightly longer to exit. .LONG TERM...(Thursday through Tuesday) Issued at 459 AM EST WED JAN 15 2020 Models suggest that a progressive pattern will prevail into next week with a gradual trend toward milder weather after this weekend. After a period of LES Thursday into Thursday night, the main story will be the impacts from the mid/upper level trough moving through the region, including the potential for moderate to heavy snow followed by signficant LES. Thursday, ongoing nw flow LES will continue with the potential for a heavier band developing near or just to the east of Marquette where land breezes will help to focus low level conv, per high res models. The band should then gradually shift toward Munising. With inversion heights near 6k ft with, and lake induced CAPE of around 500 J/Kg a period of heavier snow may be possible in the morning. However, confidence in the band(s) location/duration is low. As sfc ridging moves into the area, the LES will diminish during the afternoon as winds gradually back and inversion heights lower to around 4k ft. Overall amounts in the 2 to 4 inch range of fluffy snow will be possible as the DGZ remains positioned in the convective layer. Lighter LES will also continue over the west but with amounts of an inch or less. Thursday night, any remaining LES will diminish and end as the ridge builds into the area. Some clearing will allow temps to drop off quickly inland where temps should fall toward the lower end of guidance, at least to near -10F. More lingering clouds north and east should keep readings at or above zero. Friday into Saturday, The models have been very consistent in bringing widespread snow through the Upper Mississippi Valley and western Great Lakes as a mid level trough and inverted sfc trough move through the region. Although the focus for heavier bands is less likely, broad isentropic lift ahead of the sfc trough with favorable/efficient moisture transport from the Gulf will likely bring signficant snowfall to the area. 290k-295 layer mixing ratio amounts of around 3 g/kg was consistent with the snow potential to near 6 inches. The forecast models blend was closer to the lower end GFS with QPF in the 0.30-0.60 inch range as GEFS plumes show most ensemble members with higher amounts. The ECMWF and GEM also showed higher amounts. Although there may be some eventual upward adjustments to amounts, the overall impacts from the relatively longer duration event are not expected to approach the storms from earlier this season. Saturday night into Sunday, With the passage of the surface trough nw flow LES is expected to develop. The ECMWF, with a more defined mid level trough, cyclonic low level flow and deeper moisture through Lake Superior and Upper Michigan, would be more favorable for heavy LES(especially for n flow belts) compared to the GFS. In either case, gust winds with plenty of blowing snow is also likely as the system slowly departs. Monday through Wednesday, Some nw flow LES may linger into Monday but with a trend toward a low amplitude pattern with more zonal flow, milder/dry weather will gradually spread through the northern CONUS. && .AVIATION...(For the 06Z TAFS through 06Z Wednesday night) Issued at 1149 PM EST TUE JAN 14 2020 Snow moving into Upper Michigan still looks on track for a later this morning arrival, approaching KIWD in the pre-dawn hours, then into KSAW and KCMX shortly thereafter. There could be lower visbys embedded in the main snow band, but should be adequately covered with TEMPO groups or the like in the next TAF issuance as things come into better view. Ceilings will remain on the low side through the period, with perhaps some teetering right on the IFR/LIFR edge later Wednesday into Wednesday evening. Westerly winds tonight will become northerly as time progresses. && .MARINE...(For the 4 AM Lake Superior forecast issuance) Issued at 451 AM EST WED JAN 15 2020 Northwest winds this morning will veer to the northeast briefly before becoming northwest again this evening as a trough passes over Lake Superior. Behind this trough, winds pick up tonight with a few gale force gusts to 35 knots from the NW possible. Winds will calm down from west to east through the day on Thursday as high pressure builds in over the Upper Midwest. Winds increase up to 35 knots from the south on Friday evening as a low pressure system moves across Lower Michigan from the Central Plains. Behind this low pressure system, winds become NW by Saturday afternoon and will bring a chance at gales up to 35 knots through Sunday morning. Northerly winds relax through the day Sunday and into Monday as high pressure builds over the Upper Midwest again. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...JAW LONG TERM...JLB AVIATION...lg MARINE...JAW