3:50 PM (Monday) | **Two big storms to have major impact this week on much of the nation**
Paul Dorian
Overview
Two big storms will impact much of the nation this week in a week that features the busiest travel day of the year and, of course, the Thanksgiving Day holiday. The first system will bring about another “Denver-to-Minneapolis” snowstorm over the next couple of days – similar to a storm back in October. This system will then drag a cold front across the Mid-Atlantic/NE US later Wednesday and the winds will become quite strong – too strong for any balloons to be used in the Thursday parade in New York City. The second storm of note will become a powerhouse system in the hours before it makes landfall later tomorrow night near the Oregon/California border region. In fact, this Pacific Storm will intensify dramatically in the 24 hours preceding landfall – perhaps to what meteorologists call “bombogenesis” levels which requires a drop of 24 millibars in a 24-hour period. This second storm will bring damaging winds and heavy rain to coastal sections of Oregon/California and tremendous snows to inland higher elevation locations such as the Sierra Nevada Mountains. The second storm will trek all the way across the nation and likely result in ice and snow for the Mid-Atlantic/NE US during the upcoming weekend.
Initial storm
Deep upper-level low is already sliding towards the Rocky Mountain States and this initial system to affect the US in coming days will intensify rapidly over the next 24 hours. Snow will break out this evening across the Denver, Colorado region and it’ll snow heavily in the overnight hours and on Tuesday. In fact, this could turn out to be one of the biggest storms in many years for parts of Colorado with 1-2 feet possible by late tomorrow in many spots in and around Denver. The storm will then take a turn to the northeast and bring significant accumulating snow across the central Plains and to the Upper Midwest by the mid-week time frame.
After that, the upper-level low will travel across the Great Lakes and drag a strong cold front across the Mid-Atlantic/NE US on Wednesday evening. Winds will pick up noticeably in this region on Wednesday ahead of the front from a southwesterly direction and then will shift to northwest for Wednesday night and Thursday and will continue to be quite strong - gusts past 40 mph. In fact, winds are expected to be so strong on Thursday that the NYC Thanksgiving Day parade has already cancelled plans to have balloons at this year’s event. There will be a few showers associated with this frontal system later Wednesday, but the winds will be the bigger story.
Second storm
A major storm will form in the eastern Pacific over the next 24 hours or so and make a likely landfall near the Oregon/California border late Tuesday night. This system will intensify so rapidly, in fact, it’ll perhaps classify as a “bombogenesis” case whereby the central pressure drops by at least 24 millibars in a 24-hour period. This ocean storm will produce significant rain and wind for coastal sections of Oregon and California with hurricane-force gusts on the table. Heavy mountain snows are likely inland across, for example, the higher elevations of the Sierra Nevada where snow will be measured by the foot.
The upper-level feature associated with this storm will then take a trek to the Northern Plains, but at that point, it’ll kind of run into a “atmospheric roadblock” in the atmosphere as high pressure ridging builds across southern Canada and this will force a slide to the southeast. This drop to the southeast is an important track change as it’ll allow cold air to extend southward into the Mid-Atlantic/NE US this weekend before the system arrives and this could result in significant ice and/or snow for some interior locations in the late Saturday/Sunday time frame. Following the passage of this weekend storm, a cold air mass will flood into the Mid-Atlantic/NE US as we begin the new work week and the new month of December.
Stay tuned…a very active pattern is developing for much of the nation.
Meteorologist Paul Dorian
Perspecta, Inc.
perspectaweather.com
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