Herb Is Bullish On The Second Half Of This Season.
The past week has been another relatively quiet one over the eastern half of the country in terms of fresh snowfall while the Pacific Northwest and British Columbia have again been targeted with substantial new inches. The lack of snow over the Midwest and East has surprised me to a degree because even though deep cold air has been lacking at times, the jet stream pattern of a ridge over Canada with a trough cutting underneath it in the U.S. that set up shop about ten days ago is one that typically produces storms and snow. As the old weather adage goes “the weather doesn’t happen at the 500 millibar (jet stream) level. Sometimes you can get the pattern right but get the weather wrong”. Last week this first weekend in February looked very promising for snow along the length of the Appalachians, but the northern and southern branches of the jet will remain separate and not phase, which would be necessary for a substantial snowfall. The northern branch feature will slide from the Lakes into the Northeast, producing light snows, but it looks like another case of the big one getting away.
In the Northwest, the onslaught of storms will continue into at least the middle of next week. Initially, snow levels will bounce up to 7-8 thousand feet this weekend before crashing for the second half of the weekend to as low as 1,000 feet in places. The changes in snow level will not be as dramatic next week as colder air from western Canada gets involved in the pattern with time. In the northern Rockies, some light to perhaps moderate snow will fall this weekend as the Pacific system moves further inland. Elsewhere in the West, the central and southern Rockies and Sierra will be dry for the next several days before some early week lighter snow moves in.
The cold air that will flow into the Northwest is an indication that the refrigerator in northwestern North America has been working. If we look at the expected standard deviations of temperatures over Canada for the next ten days, the positive values have dropped quite a bit recently and negative anomalies are building in the Yukon. Here is a look at that map:
Last week I talked about an expected change in the jet stream set up that could deliver some of that cold air, and it looks like it is going to happen. Here is a jet stream forecast for 2/8 that I agree with:
A ridge is forecast to extend northward to Alaska, where a trough sat a week ago. The trough spread mild Pacific air into the pattern but having a ridge in that spot will help deliver air from the newly-minted cold in NW Canada. The multitude of troughs over the lower 48 at this time suggests a snowy pattern for many areas, much of the West, the upper Midwest, and the length of the Appalachians. That might be asking a lot, but once that cold air gets tapped, the pattern is going to get busy, and I believe snowy. I am sticking with my analog years, and I remain bullish on the second half of this season, even in areas where snow clouds have been rather stingy thus far.
Here Are The Regional Details.
Northwest U.S./Western Canada: Highest elevations, above 8,000 feet or so, get tagged every few days until further notice. Snow levels will jump up then crash this weekend in WA and OR Cascades, then stay rather low next week.
Sierra: Light snow far north. Tahoe gets light snow Sunday while southern Sierra watch storms go by to the north for a while as ridge offshore plays defense and deflects Alaskan storms.
Northern Rockies: Light to locally moderate snows Sunday as “leftovers” move inland from WA and OR. Arctic air leads to colder weather on the slopes next week. Another light to moderate snow later in the week.
Central and Southern Rockies: Light snow early next week as weakening Pacific storm limps into the region. Another round at the end of the week.
Midwest: Light snow Saturday northern Lakes. Clipper system produces light to moderate snow Thursday of next week. Arctic invasion on the horizon should produce good snowfall Week Two.
Northeast/QB: Weekend ocean storm misses but northern disturbance brings light snow to upstate NY and northern New England/southern QB. Milder early next week with fresh snow by midweek as cold returns. Pattern change bullish for February and beyond.
