Brendan Heberton

The winter was interesting in a couple of ways: the strength and duration of the
ridging over the West, and the number of stretched polar vortex events impacting
the East.

This pattern does break down a bit in March, but does not appear to change
quickly enough to alter the late-winter pattern as we start spring.

Analog years suggest colder than normal conditions across the West, which spread
onto the plains. Global models have struggled with the placement of coldest
temperatures this winter, but are leaning toward what the analogous years
suggest for march. 

That model image above is from the American GFS. That particular model has been
handling the overall pattern over the Northern Pacific better than it has off
the East Coast – not only this year but much improved over last year.

That model, and others, does have a wet bias. Keep that in mind as we look at
the precipitation for the month.

Modeling has suggested wetness across the Pacific Northwest all winter pretty
much and again we see that is the case despite how hard it has been to actually
receive surplus water here.

What that precipitation image shows is a storm track which favors a Vancouver to
Chicago to Boston track – roughly speaking, of course. Basically, the same areas
that have had moisture this year to date will continue to stay in that pattern.

To test the legitimacy of that model's projection, it does match that of the CFS
and ECMWF in placement of the storm track and highlights the similar dry and wet
areas.

A further check is with analog years, which do give us the normal and drier than
normal conditions across the Pacific Northwest across the northern tier of
states. A moisture-sparse outlook for much of the West.

The drier forecast based on history for the western U.S. makes sense both in
terms of modeling's wet bias here and how the past couple months have progressed
under a similar pattern.

When it comes to Colorado, I don't see us breaking the established pattern since
January. This gives us periodic moisture to the mountains, as well as on the
Front Range.

If a persistence method applies here, we'd see a similar precipitation pattern
for March as we have seen since January 1st. 

One change could be a more favorable pattern for the mountains (vs the image
shown below), especially along and north of I-70. For the Front Range, areas
along and north of I-70 are also likely to be favored for the better
precipitation chances as we head through the remainder of the month. 

The temperature pattern has been cool since January 1st. 

I'd be surprised if southern Colorado can remain cooler than average. Analog
years and model projections also place that region in a normal to warmer than
normal outlook for the month.

March storm track could mean more of the same, favors northern tier of U.S.