Probabilistic Heavy Snow and Icing Discussion NWS Weather Prediction Center College Park MD 420 AM EDT Thu Apr 14 2022 Valid 12Z Thu Apr 14 2022 - 12Z Sun Apr 17 2022 ...Northern Plains/Upper Midwest... Day 1 The blizzard that has been hammering North Dakota over the past couple of days will continue to abate on Thursday as the core of the surface low and its associated deformation zone becomes more elongated and lifts northward across south-central Canada. However, impactful conditions will remain in place as the pressure gradient remains tight and strong, gusty northwest winds will result in considerable blowing and drifting snow from far eastern Montana to far northwestern Minnesota. There will also be some additional mainly light snow accumulations for many of these same areas through about 6Z Friday as wrap-around moisture lingers in place. There will likely be a few inches of additional snow across northern North Dakota and into northern Minnesota. There is also the chance for a few snow squalls amid steepening lapse rates south of the main low pressure center on Thursday from the Dakotas across southern Minnesota and into northern Wisconsin. Snow will continue to wane and winds subside Thursday night and especially by 12Z Friday as the low lifts farther northeast across Ontario, and very cold high pressure settles into the northern Plains to conclude the week. ...Central West Coast region to the Northern Rockies... Days 1-3... An upper level low will continue to have staying power over the Pacific Northwest through early Friday, followed by a reinforcing trough reaching the West Coast Saturday morning. This will maintain a cold and unsettled pattern across the region through the upcoming weekend. The first of two disturbances will be ongoing at the beginning of the forecast period across northern California, with moderate accumulations expected for northern portions of the Sierra and the Siskiyou Mountains through about 6Z Friday. Following a brief lull, a slightly stronger disturbance reaches northern California Friday evening and brings a heavier round of snow that will likely affect the southern Oregon Cascades as well as the northern California ranges and the Sierra. The low-mid level moisture plume will track eastward across the Northern Rockies through the day Saturday, and potentially reaching the western Dakotas by 12Z Sunday as a 850-700mb frontogenesis band develops ahead of the main surface low. ...Northeast states... Day 3... A reinforcing cold front is progged to settle southward from the Ohio Valley to the interior Northeast Friday night and into Saturday morning. Although the air mass in general along and ahead of the front should be warm enough to support mainly rain, there is some signal in the guidance for a change-over to wet snow for several hours across the higher terrain of Upstate New York during the day Saturday as mid-level height falls move across the region, and then reaching central portions of New England by Saturday night. The greatest accumulation would be favored across the Adirondacks, where several inches of accumulation will be possible. For Days 1-3, the probability of 0.10 inch or more of ice is less than 10 percent. Hamrick ~~~Key Messages for April 13-14 Blizzard~~~ --Conditions will slowly improve across North Dakota on Thursday as snowfall intensity wanes. Some snow squalls are also possible across portions of central Minnesota and into northern Wisconsin Thursday afternoon. --The combination of light to moderate snow and strong wind gusts will produce areas of low visibilities, with significant blowing and drifting of snow. --Travel will remain very hazardous through Thursday afternoon, with some additional power outages possible. Road conditions should improve by Friday. --Snowfall intensity will diminish by Thursday afternoon for most areas, with additional accumulations up to 4 inches possible.