The Next Storm/Next Snow Forecast Discussion from the Cherrywood Observatory – August 12th, 2018

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Figure 4: the 3 month temperature anomaly outlook for N. America (Longmont is the pink dot) issued July 19th.

Forecast Discussion:

Amazingly, we move another notch drier today. There is only 1/2 inch of precipitatable water in the atmosphere as of Saturday morning (we get excited about rainfall as it approaches an inch or more). We have orange and red colors painted overhead on the water vapor satellite image (Figure 1). The thicker smoke is a few counties closer to us than it was yesterday as that next trough begins to dig into the Pacific Northwest (it is a very sharp clean cut into the smoke in Washington State and Oregon on Figure 2!).

The precipitation for the next 3 days is extremely close to zero on the GFS outlook (Figure 3).  A touch of monsoon moisture may wet the Western Slopes over the next few days.  That would be nice.

Figure 1: the water vapor satellite image from Saturday AM. Reds/Oranges are dry air, greys/whites are moist air regions.
Figure 2: The HRRR (high resolution rapid refresh) model forecast of smoke at all levels for Sunday midday.
Figure 3: The total accumulated precipitation for the next 3 days between Saturday AM and Tuesday AM from the GFS and

The longer range forecast:

Our rain forecast is pegged at zero until Tuesday afternoon. A bit of moisture returns then, with a deeper surge showing up on Friday (Figure 4). We might be seeing our last 90’sF this weekend and Monday.

Since the weather is very quiet, let’s look at some really long range trends.  Based on the longer range models and sea surface temperature trends, NOAA has painted us (Figure 5) as having better than average chances of being warmer than normal for the end of the Summer into the Fall (September, October, November or “SON” in the legend).  Similarly, the precipitation outlook for this time (Figure 6) has us at near normal precipitation with above average amounts in the desert southwest of the U.S.

Figure 4: the next 10 days of the graphical forecast for Longmont, CO from
Figure 5: the 3 month temperature anomaly outlook for N. America (Longmont is the pink dot) issued July 19th.
Figure 6: the 3 month precipitation anomaly outlook for N. America (Longmont is the pink dot) issued July 19th.
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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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