Subj : HVYSNOW: Probabilistic Heavy Snow And Icing Discussion To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Wed Feb 08 2023 08:19:32 FOUS11 KWBC 080819 QPFHSD Probabilistic Heavy Snow and Icing Discussion NWS Weather Prediction Center College Park MD 318 AM EST Wed Feb 08 2023 Valid 12Z Wed Feb 08 2023 - 12Z Sat Feb 11 2023 ....Northern to Central Rockies... Day 1.. A strong arctic cold front, associated with an amplifying shortwave diving southeast from the Pacific Northwest, will continue to push from the northern Rockies to the central Rockies today. While widespread heavy snow accumulations are not expected, sufficient low level moisture, instability, and wind will continue to raise the threat for brief but intense snowfall and reduced visibility. See the key messages below for additional information. ....Mid Mississippi Valley to the Upper Midwest and Northeast... Days 1-2... An upper low moving into the southern High Plains this morning is expected to lift northeast ahead of the previously noted shortwave diving southeast across the Rockies today. As the two systems interact and the leading wave begins to assume a negative tilt, an intensifying surface low is forecast to track northeast across the lower Missouri and mid Mississippi valleys tonight. Warm air ahead of the system will support mostly rain at the onset, however increasing ascent is expected to encourage the development of heavier precipitation and a changeover to snow within the associated deformation band as it lifts across the lower Missouri and mid Mississippi overnight into early tomorrow. While widespread heavy amounts are not expected, a slushy inch or two of snow is possible by early Thursday across northern Missouri into central Iowa. As the system continues to intensify and track northeast into the upper Great Lakes, a changeover to predominately snow is expected to occur within the comma-head. A coupled upper jet along with strong low-to-mid level frontogenesis is expected to support moderate to heavy rates on the northwest side of the low. The overnight guidance shifted a little farther southeast with the track of the low, moving the higher probabilities for snow accumulations of four inches or more a little farther southeast across northeast Iowa, southern Wisconsin, and northern Michigan. WPC guidance indicates that snow accumulations of 4 inches or more are likely across this region, with a good chance for amounts of 8 inches along a corridor extending from southwestern Wisconsin toward Green Bay. Ahead of the low, warm air moving across the top of retreating cold air will support a wintry mix advancing across the Northeast on Thursday into Thursday night. Before changing over to rain, areas of accumulating ice are expected from Pennsylvania to northern New England, with sheltered locations within the Adirondacks and northern New England mountains mostly likely to be impacted by a period of prolonged icing. At least a few inches or snow is expected across northern Maine, where the precipitation type is most likely to remain snow through the event. Pereira ....Key Messages for Northern and Central Rockies Snow Squall threat today... --Snow Squalls in Northern and Central Rockies A cold front pushing south from the northern Rockies to the central Rockies on today will bring snow squalls and scattered snow showers. --Gusty Winds Also Expected in the Region Widespread wind gusts in excess of 50 MPH, with gusts as high as 65 MPH, will lead to difficult travel conditions, especially to high profile vehicles in strong crosswinds. --Bursts of Heavy Snow and Low Visibility Snow squalls and snow showers will produce brief bursts of heavy snow. This will lead to sudden reductions in visibility, especially in areas of strong wind gusts. --Expect Rapidly Changing Conditions Anyone traveling on roads through the northern and central Rockies should be prepared for rapidly changing conditions, potentially going from sunny skies to near whiteouts in a matter of minutes. Use caution if traveling. $$ = = = To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM. --- SBBSecho 3.14-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .