Forecast Discussion:

The front came through about three hours later than I called for on Friday. We had clouds, winds, and virga (rainfall that evaporates before hitting the ground). Figure 1 shows the position of the front as of Saturday late night (about the time I was setting clocks forward).

Figure 2 is the upper air map for Saturday PM – the red line to our east (pink dot for Longmont) is the upper air feature that brought the front in.  The ridge to the west (big blue line) is growing!

Figure 1: Current Surface map from Saturday PM from the weather channel.
Figure 2: The current 500mb upper air map from Saturday PM from the RAP model.

The longer range forecast:

This week will be quite warm and dry. Monday will see mid 50’sF.  Tuesday upper 60’sF.  Wednesday 70’sF. This is the work of the big ridge.  Figure 3 is the upper air map for Tuesday night, the ridge is almost overhead.

The deep trough over the eastern Pacific ocean in Figure 3 will replace that ridge by the weekend (see Figure 4 – Saturday night). Some models are now bringing in 2/3’s of an inch of rain Saturday PM through Monday next week.  Figure 5 is a zoom-in on the weather for next weekend.  This model has about 1/2 of an inch of rain.  Note temperatures remain too warm for much in the way of snow.  That’s how it looks for now.  Tune in again tomorrow!

Figure 3: The 500mb upper air map for Tuesday PM from the GFS. Troughs in red, ridges in blue.
Figure 4: The 500mb upper air map for Saturday PM from the GFS. Troughs in red, ridges in blue.
Figure 5: the last 3 days of the 10 day graphical forecast from
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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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