In Brief:

Nearly perfect weather continues through Monday midday. Drop mic.

A cold front and deep upper air trough move in Monday afternoon and a long period starting with thunderstorms continuing with rain and nighttime snow at times runs Tuesday through next Monday and beyond.

Forecast Discussion:

High pressure (with some clouds) continues today. The ridge will build a bit more overhead – so temperatures will warm a touch more. West winds at the surface will warm things a bit to the upper 70’sF.

The Longer Range Forecast:

With the next trough coming in just a bit sooner, and with clouds increasing, we will probably only see the lower 70’sF on Monday. The front should slide down the front range increasing our chances of rain and thunderstorms around sunset (big blue line Figure 2). We probably won’t see severe thunderstorms along I-25 and westward, but we may see a marginal or slight risk out on the eastern plains. I’ll update you on that as we get closer.

A quick check on the GFS 10-day total water has us in, what is probably, a down slope notch again, but we do get 1 to 1.25 inches of water. The bullseyes of heaver precipitation are staying consistent to our west and east (Figure 3). The GFS has no Longmont snow but the GEM (Figure 4) does give us 1-2 inches (or a touch more) snow over the next 10 days. If anything accumulates, it should ‘wash’ away in the daytime rain and temperatures that follow.

Figure 1: The forecast surface map for Friday PM from NCEP.
Figure 2: the graphical forecast for the next 10 days for Longmont, CO from weatherunderground.com
Figure 3: the forecast accumulated precipitation map from the GFS and weather5280.com for Colorado,over the next 10 days.
Figure 4: the forecast accumulated snow map from the GEM and tropicaltidbits.com for Colorado, through the next 10 days.
SHARE
Previous articleInterview: Ellen Burnes–Candidate for U.S. Senate 2020
Next article2018 Drinking Water Quality Report Available Online
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.

Leave a Reply