Next Storm/Next Snow Forecast Discussion from the Cherrywood Observatory – June 15, 2019

Figure 1: The forecast surface map for Saturday night from NCEP.

In Brief:

We enter a 4-5 day period of warmish weather with daily weak cool fronts that will kick off showers and thunderstorms around midday and into the afternoons. Severe weather is not expected over this period (at this time). This site will be updated if changes. Our five day rainfall total will probably remain below 1 inch.

Forecast Discussion:

Our first not-so-cold front came through today (Friday) and will still be draped down the front range Saturday afternoon (Figure 1). Widespread showers will peak between mid-morning and mid-afternoon Saturday.

Temperatures are a bit cooler Saturday: in the mid 70’s F. Diminished rain chances continue into the the night. Most likely about 1/10th of an inch of rainfall will hit the area Saturday, more under a thundershower cell (Figure 2).

The Longer Range Forecast:

Each midday you can see a pressure dip, the winds increase, a dip in the temperatures and increase in rain chances for a few hours (Figure 2) through Tuesday. Most seem to time with max daytime heating (to increase instability). This is all driven by a trough-y pattern in the west with many short waves drifting through the overall upper air pattern (chaotic red dashes in Figure 3). Over the next 5 days, from the GFS, Longmont receives (in this particular run of the model) around 3/4th of an inch of water. Like our longer range glimpse yesterday – cooler than normal and wetter than normal. We are on track with that forecast already.

Figure 1: The forecast surface map for Saturday night from NCEP.
Figure 2: the graphical forecast for the next 10 days for Longmont, CO from
Figure 4: The 500mb forecast upper air analysis for Monday AM. Pink dot is Longmont. Red lines are troughs, blue lines are ridges.
Figure 4: the forecast accumulated precipitation map from the GFS and for Colorado,over 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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