The Next Storm/Next Snow Forecast Discussion from the Cherrywood Observatory – December 6, 2017

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Figure 3: surface air temperatures 2pm Wednesday forecast.

Forecast Discussion:

The Wednesday front comes racing in today, but things remain dry. Figure 1, the water vapor satellite image, shows that the tropical moisture is far to the south. But this front will bring in strong winds today (Figure 2). This figure has winds sustained around 20mph from the NNW around Longmont (and stronger up north).  Real cold air comes in as well with a high staying in the 30’s today (Figure 3).  Bundle up!

Figure 1: Tuesday PM Water Vapor satellite image (dry air= red/brown, moist air = purple/white)
Figure 2: The surface winds – directions with flags, speed in colors for Wednesday afternoon.
Figure 3: surface air temperatures 2pm Wednesday forecast.

The longer range forecast:

Another front keeps temperatures cold for Thursday (Figure 4). We stay in the 30’s tomorrow as well (with more wind).  There IS a chance of snow flurries around for this storm (but not much). Figure 5 is the total snowfall accumulation through the end of this week, and there is a dusting in the mountains and on spots on the Plains. Longmont probably remains dry.

By Friday (Figure 6) the western ridge finally moves in and we rapidly shoot up to highs in the 50’s and then 60’s on Saturday.  Go get a tan!

(The pure fantasy Christmas forecast, from accuweather.com, has cooled to highs in the upper 40’s, but only partly cloudy skies.)

Figure 4: surface air temperatures 2pm Thursday forecast.
Figure 5: Total snowfall between now and Friday night from the GFS.
Figure 6: The GFS upper air forecast map for Friday PM.
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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.