Matt Makens

February’s weather pattern has a chance to deliver lots of moisture for the
Front Range and Plains. If you reread that sentence, you’ll see, “chance.” This
El Niño winter has had moments of delivering lots of snow to the state – think
back to the epic two weeks of snow for our Colorado resorts, especially 
Steamboat Resort [https://www.steamboat.com/] (third snowiest January since
08/09 season)
[https://www.instagram.com/p/C2is1jEgfMv/?utm_source=ig_embed&ig_rid=0846d993-9761-4a7a-9e95-14e308dee168&img_index=1] 
but we’ve come short of what I would call an exciting winter along the Front
Range. This may change in the weeks ahead, or at least there are moments when it
looks like it wants to make the change.

As we near the first weekend of February, there will be a buzz about a pattern
change, and from time to time, you’ll even see some massive-looking snowfall
totals floating on your various feeds. Internally, we have been chatting about
an elongated trough supporting good upslope from this Friday through Sunday.
This same trough that put down an inch and a half of liquid on Colorado Springs
and the Front Range, dries up in the subsequent model update. However, the
pattern is what it is, and there are chances for something to materialize.

Let’s get to the basics. The MJO is ending one of its strongest events of the
season. Still, as it tends toward neutrality, it will leave an energized
Jetstream screaming from near Hawaii to the Southern U.S. This will encourage
troughing across the Western and Southern U.S.

From a basic standpoint, we can see that evidence is in a strongly positive PNA
phase for the month ahead (a strongly positive PNA supports storms for our neck
of the woods). From a purely historical standpoint, here is an analysis that
shows the wetness frequency of the previous +PNA Februarys.

Of these connections, the PNA has the strongest “signal” for this February. With
that, we expect to see significant troughing enter the picture, and using the
Euro Ensembles, we can see that troughing. The weekly average for the first week
of February shows a significant focus on active weather, potentially from coast
to coast. 

The blocking ridge over Canada may also come into play in the ultimate speed and
path of any storm that decides to visit Colorado. Should it slow things down,
all the better for metro area snow lovers.

Modeling has had a lower correlation skill score beyond day 10 and has a wide
uncertainly at even longer ranges. Still, assuming the PNA remains strongly
positive, as it appears it will, we have more than just the first week of the
month for potential moisture.

If we combine some of the bigger climate drivers for February together, we can
get an analog-based idea of what the month in total may be. Here is that in
terms of moisture frequency and temperatures. Since the MJO is trending toward
neutral, it isn’t considered here, but if models struggle with that projection
and we see another spike in the MJO, that could change things later in the month
by reinforcing that screaming Jetstream across the Southern U.S.

For now, let’s focus on the first week of February, and yes, we have seen the
potential for a very wet system to hit the state, especially along the Front
Range and Plains. Before we jump on every model run that shows epic snow, let’s
keep in mind that we are a way away and we all know how things will change.
We’ll have plenty more updates on this next potential system for next weekend in
future posts.

Insiders: February's potential to slam the Front Range, or merely graze