Forecast Discussion:

With a front draped nearby and a small ripple in the upper atmosphere interacting with it, we do have light snow showers in the mountains (yes again) and some sprinkles coming out on the Plains/I-25 Monday evening. This is a very small scale system hitting areas around town this evening. It is nice that the weather is somewhat unpredictable (ripples in the upper atmosphere like to do this in northwest flow). You can barely make out the streak of showers around and east of the pink dot north of the low and front in northern Colorado (Figure 1) currently (Monday PM).

Tuesday, the convergence zone with the front sags south leaving us in cool air for another day (Figure 2). Light mountain snow showers continue.

After this system clears, we warm to the 50’s F Wednesday (Figure 3).

The longer range forecast:

A trough digs into the western US later in the week and a big cutoff low forms to our west and drifts slowly eastward. We end up in a moist, cloudy and showery (but still warm) period of time Friday through Monday (Figure 3).

Water amounts will be light through this period – the next 5 days of snow show nothing in town (the heavier snow totals are in the southwestern mountains again (Figure 4). Rainfall is the story with this system. Most of Longmont should see around 1/10th an inch of water over the next 5 days.

Figure 1: The current surface map from Monday PM and the Weather Channel.
Figure 2: The forecast surface map for Tuesday PM from NCEP.
Figure 3: the graphical forecast for the next 10 days for Longmont, CO from
Figure 4 : the forecast accumulated snow map from the GFS and for Colorado, through Saturday midday.
Figure 5 : the forecast accumulated precipitation map from the GFS and for Colorado, through Saturday midday.

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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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