Forecast Discussion:

Things are quiet locally with a big warm up in store for us over the weekend. A ridge is moving overhead and a stationary front will push east as a warm front early today (Figure 1). The monster storm, now down in Texas, is headed to meet the cold air associated with the high pressure centered over Missouri and Illinois right now. Enjoy this wonderful weekend!

Figure 1: The current surface analysis map from Friday PM and from

The longer range forecast:

By Sunday, we’ll see a ripple and weak cool front kick up mountain snows to our west, but in town, we’ll be high and dry. The monster storm is really dumping rain, ice, sleet and snow on the southeastern U.S. states by the end of the weekend (Figure 2).

Our next chance of snow comes with a cold front and upper air trough coming in on Wednesday night (Figure 3). The upper air trough looks pretty significant (Figure 4 – red line on top of us and cutoff isopleth overhead) with a good blob of surface precipitation over the region (Figure 5). Figure 3 still only forecasts about an inch of snow then. We’ll keep watching it, as always.

Long Range (fantasy) Christmas Forecast:

There still is no hint of a major snow storm between now and Christmas Day for Longmont. Christmas Eve and Day look to be in the 30’s F for highs and around 10°F for lows. Christmas Eve is cloudy while Christmas Day is clear. We’ll watch that too as the weeks pass.

Figure 2: The forecast surface map for Saturday night. From NCEP.
Figure 3: the graphical forecast for the next 10 days forecast for Longmont, CO from
Figure 4: The 500mb forecast upper air analysis for Thursday AM. Pink dot is Longmont. Red lines are troughs, blue lines are ridges.
Figure 5: The surface forecast analysis for Thursday AM. Pink dot is Longmont.


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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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