Forecast Discussion:

Groundhog update! To quote the CNN headline: “Groundhog predicts an early spring. Don’t get too excited, he’s usually wrong.

Locally, it was sunny and abnormally warm in Longmont. Today, a Pacific cold/cool front sweeps in with precipitation all across the west, but we’ll see down-slope winds and not much of a cool down and no precipitation (Figure 1). You can see the pressure drop Sunday midday in the black line stretching across the middle of the graphic of Figure 2.

The harbinger of change is up in Canada right now. Figure 3 shows the next blast of fantastic cold much further west than the one that hit Chicago and the Midwest. I’ve drawn in a cold front (pretty bad artwork) on the margin of this invasion.

The longer range forecast:

In Figure 4, the cold air (not as extreme as what we saw the last week out east of us) is flowing over us and invading New Mexico, Texas and Oklahoma on Wednesday/Thursday.  We’ll be some 20 to 25° F below normal. With that invasion, we’ll have a period of cold up-slope flow and snow, then colder temperatures for a while. Weatherunderground (Figure 2) gives us 1-3 inches. The GFS (Figure 5) gives us a coating to 1 inch. It is too soon to really say. You’ll have to come back for more!

Figure 1: The forecast surface map for Sunday night. From NCEP.
Figure 2: the graphical forecast for the next 10 days for Longmont, CO from weatherunderground.com
Figure 3: The forecast temperature departure from normal map from the GFS and weather5280.com for Colorado, Sunday noon.
Figure 4: The forecast temperature departure from normal map from the GFS and weather5280.com for Colorado, Thursday noon.
Figure 5: the forecast accumulated snow map from the GFS and weather5280.com for Colorado, through Thursday morning.
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John Ensworth works from Longmont as the Principle Investigator for the NASA Science Mission Directorate Earth and space science education product review through the IGES (The Institute for Global Environmental Strategies – www.strategies.org) . He is in his 14th year running this review. He is an astronomer (from the 2nd grade onward) and became a meteorologist (in the 5th grade) when a thunderstorm in Arizona rained on his telescope when the weather service had only forecasted a 10% chance of rain. He has college degrees in physics and astronomy and climatology and a graduate degree in meteorology and earth science. He lectures at the Little Thompson Observatory in Berthoud, the Estes Park Memorial Observatory in Estes Park, and for a number of online universities. He built and runs a backyard observatory near Pace and 17th in northeast Longmont where he has lived for 8 years with his wife, daughter, son, and two cats. Invitations to open house nights at this observatory, LTO, and EPMO will be posted with future discussions when they are scheduled. Forecasting severe weather and snow amounts via text lead to this column. He began texting friends about the weather right after the September 2013 flood. The readers of this column will, hopefully, keep him honest in what he ‘thought’ he had forecasted for ‘the most recent’ storm.

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