Next Storm/Next Snow Forecast Discussion from the Cherrywood Observatory – April 21, 2019

Figure 1: The forecast surface map for Sunday PM from NCEP.

The weather in brief:

I’ve had a request to make these discussions a big shorter – but sometimes I have a lot to say. So I’m going to try a “weather in brief” section up front, then go into more details below in the forecast discussion. If you want it quickly, it’ll be up here. If you want all the messy model stuff, it’ll be below. Tell me how this works for you in the comments section!

In brief, the storm is shaping up to have less moisture and be stronger up in Wyoming – so much less rain is expected from 2pm Sunday to Tuesday. Maybe only 1/4 th inch. We cool to just a bit below normal for a couple days then warm up again all week.

Forecast Discussion:

The Sunrise Forecast for Easteris now looking as:

6:00am, Partly cloudy skies 50F with no rain. Cloud cover at 40%. Winds from the West or Northwest at 3mph. Pretty nice!

The storm has changed its characteristics over the last couple of days. The may dynamical lift of the system will remain north of our area and there is less moisture expected in the atmosphere (maybe only 0.6 inch of precipitatable water). Rather than an inch or more of water, we may only get a few tenths according to some models.

For Sunday afternoon, there is a front draped across the state with rain near and north of the front (Figure 1). The graphical display at is broken but their tabulated data shows rain chances holding off until around 2pm, and much more minimal than we’ve been watching this week (I’m sad – Figure 2).

The GFS gives almost NO rain over the next 3 days (Figure 3). The NAM only gives us about 1/3rd inch of rain (Figure 4). Snowfall over the next 3 days is a mere shadow of what we saw just a day ago in the models – up in the mountains and foothills (Figure 5).

The longer range forecast:

We drop to the 50’s briefly Monday (but remain above freezing at night) – then warm to the 70’s and 80’s (by the end of the week). Things stay dry the rest of the week (Figure 6). Happy Easter all!

Figure 1: The forecast surface map for Sunday PM from NCEP.
Figure 2: the tabulated forecast for the next day for Longmont, CO from
Figure 3: the forecast accumulated precipitation map from the GFS and for Colorado, through Tuesday night.
Figure 4: the forecast accumulated precipitation map from the NAM and for Colorado and areas east and south, through the next 3 days.
Figure 5: the forecast accumulated snowfall map from the GFS and for Colorado, through Tuesday night.
Figure 6: the graphical forecast for the next 10 days for Longmont, CO 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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