Forecast Discussion:

Friday’s storm blew through with mainly rain, wind, and snow under the heaver convection (Figure 1). We had only a few 100th’s of an inch in town. We have a few, somewhat below normal (temperature-wise – Figure 3 ) days ahead of us as the weekend ends and the week starts. Snow continues in the mountains (Figure 2). What’s new?

The longer range forecast:

Our mid-week storm is looking better and bigger (if you think a bigger snow storm is better). Figure 2 shows it beginning with rain as warm southwest flow covers the state. The upper-air pattern, in Figure 4, shows what is called a negatively tilted trough over the state Wednesday (the red line upper left to lower right over Colorado). There is even a closed circle over SE Colorado all describing a strong, classic, spring storm with blizzard potential out on the eastern Plains. This will have lift, jet stream support, and strong up flow over NE Colorado, and a lot of moisture (if it pans out).

We are still too far out to be certain, and not all models are creating this scenario, but more are looking to come in line with this picture.

The model in Figure 3 shows us getting 5-8 inches of snow.

The GFS in Figure 5 also gives us 5-8 inches.

The GEM in Figure 6 is more in the line of 2-4 inches.

Stay tuned!

Figure 1: total new snow totals for Friday/Saturday up to 7am for Boulder county from CoCoRaHS.
Figure 2: The forecast surface map for Sunday PM from NCEP.
Figure 3: the graphical forecast for the next 10 days for Longmont, CO from
Figure 4: The 500mb forecast upper air analysis for Wednesday AM. Pink dot is Longmont. Red lines are troughs, blue lines are ridges.
Figure 5: the forecast accumulated snow map from the GFS and for Colorado, through the next 5 days.
Figure 6: the forecast accumulated snow map from the GEM and for Colorado, through the next 5 days.
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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 – . 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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