Skip to content

The Next Storm/Next Snow Forecast Discussion from the Cherrywood Observatory - Sunday July 30, 2017

By John Ensworth Discussion: Too much of a good thing. We got moisture jammed up under the upper level ridge rotating around a lower level high pressure circulation in the NW Texas area.
2

This content was originally published by the Longmont Observer and is licensed under a Creative Commons license.

By John Ensworth

Discussion:

Too much of a good thing.  We got moisture jammed up under the upper level ridge rotating around a lower level high pressure circulation in the NW Texas area.  Figure 1 shows the circulation of dry air near the High center, and moisture around the perimeter.

Figure 1:  The water vapor satellite image for Saturday night.

The saturday evening radar (Figure 2) shows where the rain and thunderstorms formed. They came together where the healthy moisture flow met the drier air. Southern and eastern Colorado was close enough to the high and the dry air to get some clear skies and warming of the lower, but moister atmosphere.  Up here in  Longmont, it stayed too cool and stable for much more than light showers to form.

Figure 2: Saturday PM southwest U.S. radar.

The precipitatable water has climbed with a return of lower level winds favorably tapping the monsoon moisture.  This next image is the Denver Sounding for Saturday night. We’ll go into detail, in future columns, about all the interesting information in this plot, but at its core, it is the temperature (red line) and moisture content (green line) measured by a weather balloon released from DIA at 6PM Saturday.  This is the tool that tells us what the precipitatable water value is – and it is just a touch over an inch now.  Oh if only the sun had come out today along the Front Range.

Figure 3: The 500mb map – current conditions Friday PM.

In a look at the longer range: The low level moisture sticks around into middle to late next week, but the ridge heads back west, eventually as far as California early next week (see Figure 4).  The moisture getting in under the ridge will ebb and flow giving us a chance of afternoon thunderstorms just about every day. Figure 4 also shows how far north the ridge builds on the west coast by mid-week.  This will allow weak cool fronts to travel down over the state keeping highs in the 80’s most of the period.  Somewhat moist and not too hot… that is a good way to run a summer.

Figure 4 The 500mb map for Thursday morning.  The northerly flow over Colorado is marked in dark blue and the ridge axis in a slightly lighter blue.

*** This feature will run as close to daily as possible in this location on the Longmont Observer. ***

This article will provide a brief discussion concerning the ‘why’ behind the weather with a focus on severe weather, unusual weather, and snow (especially trying to predict snow depth and its human impact in Longmont).

Bio:

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.