Several Pacific disturbances are set to move across eastern Utah and western Colorado through the rest of the work week and into the weekend. The first wave will continue through this morning with the northern and central mountains favored for the most accumulation. The second storm will arrive this late afternoon and continue through early Friday. An abundance of moisture associated with an atmospheric river (AR) event will result in widespread shower coverage with this system. However, the mild nature of the AR will allow snow levels to rise to 6000 to 6500 feet across the north and between 7500 and 8500 feet across the south. As a result, many of the lower elevations will primarily receive rain. The core of the Atmospheric River moves over the Four Corners early this evening and this is when rain and snow rates will be at their greatest. Precipitable water values will peak at around 4 standard deviations above the mean- a true testament to the astounding moisture content with this system. After midnight, things will wind down fairly quickly. The moisture stream sags south and east and dry air moves in from the west by mid-morning Friday. Snow will linger the longest in the central and northern mountains, however any shower activity will end by noon even in the highest terrain.
WXD Alert: Active Discussion, Tracking, Observations
Lake effect snow is common across the Great Lakes region during the late fall and winter. Lake Effect snow occurs when cold air, often originating from Canada, moves across the open waters of the Great Lakes. As the cold air passes over the unfrozen and relatively warm waters of the Great Lakes, warmth and moisture are transferred into the lowest portion of the atmosphere. The air rises, clouds form and grow into narrow band that produces 2 to 3 inches of snow per hour or more.
A developing winter storm will bring widespread moderate to heavy snow to much of the Northeast by Tuesday night and early Wednesday. The potential exists for 6 to 12 inches of snow from northern Wisconsin to northern Michigan, and even higher amounts across upstate New York and northern New England with 12 to 18 inches possible. A corridor of freezing rain is likely to the south of the heavy snow axis, extending from the central Appalachians to southern New England, and also across southern Michigan. Significant travel impacts are anticipated through Wednesday.
...A stronger upper trough rotating out of the broader western CONUS trough from the Great Basin will quickly lift into central plains and Upper MS Valley on Sunday. Deep QG forcing with this system will bring widespread light snow to the area. There are still some subtleties to figure out with variation in the models with the highest QPF, especially if precip is enhanced in narrow fgen bands.
An area of freezing rain is expected to move over Southwestern Ontario Wednesday morning. The freezing rain could persist for much of Wednesday before ending Wednesday evening or overnight. The Wednesday morning commute will likely be affected due to the potential for untreated surfaces to become icy Surfaces such as highways, roads, walkways and parking lots may become icy and slippery. Be prepared to adjust your driving with changing road conditions. Ice build-up may cause tree branches to break.
A system will form on the lee of the Rockies around February 3 and cut through the Great Lakes, perhaps making for a small risk for severe weather. However, it looks like the cold front will stall out within this region before another system forms off the Rockies as the longwave trough pushes east. By the time the final cold front pushes through, the areas south of where the cold front stalled out will have been under 150 hours, or almost 7 days of southerly winds.
...The beginning of a heavy rain/flooding pattern is setting up across the mid-Mississippi and Ohio Valleys... As the Pacific storm system mentioned above moves east Wednesday into Thursday, moisture from the Gulf of Mexico together with strong upper-level dynamics will begin to bring an increasing chance of rain for the mid-Mississippi and Ohio Valleys. Total rainfall through Thursday could range between 3 to 5 inches for portions of the Ohio Valley which may cause flooding
... Arctic cold settling into the region this evening... Canadian high pressure system builds over the region into Sunday, possible lowest temperatures of season for the northeast, as the cold air that impacted the midwest slowly pushes into the northeast. Wind chills will be painfully low on Thursday morning to close January.
An Alberta Clipper that will cross the area and result in snowfall with total amounts of about 15 to 20 centimeters is expected. Snow at times heavy is expected to develop Monday morning or early afternoon and persist into Monday night. Some areas may see snowfall totals near 15 cm by Tuesday morning, although locally higher amounts are possible closer to the Great Lakes. very cold polar air will add to the dangers as extreme cold warnings are out for the entire area.