In Brief:

With hit after hit of snow past us now, we have a quiet and warm (overall) weekend ahead of us. Our next stormy period runs from Monday morning to Wednesday morning when we may pick up an couple inches or a bit more of snow. Then we return to quiet conditions again beyond that!

Update 2/16 9pm:

The chilly weather returns as does more moisture. This doesn’t look like a LOT of snow coming, but some rain showers early Monday will change to snow later on. Accumulations of 1-2 inches is most likely in town with a possible 2-3 inches nearby to the west. Things will remain unsettled Monday morning through late Wednesday night. There are a couple of better snow chances in the blue box time frames in Figure 2 update. The GFS still gives us only a coating to 1 inch across town (Figure 3 update). More to come tomorrow!

Figure 2 update: the snippet of the graphical forecast for the next 10 days for Longmont, CO from weatherunderground.com
Figure 3: 10:1 (snow to liquid) snowfall totals through Thursday morning from the GFS and weather5280com for Colorado made Monday afternoon.

End update 2/16 9pm.

Update 2/15 5pm:

We are still on track for temperatures around 50F for Sunday and 2-3 inches of snow for Monday/Tuesday. I’m posting the weekend video forecast discussion in Figure 1 update.

Figure 1 update: Forecast Discussion video for the weekend.

End update 2/15 5pm.

Forecast Discussion:

A warm front drifts past us on Friday taking us back to the 50’sF (Figure 1). Watch out for falling icicles. This warm up is brought on by more westerly air flow across the state giving us some down slope warming. There are shallow ridges (and a trough for Saturday) that will also help with the warming (Figure 2).

Oh, and Happy Valentines Day! (I almost forgot!)

The Longer Range Forecast:

Our next storm doesn’t roll in until very early Monday (Figure 3). Hurray, another potentially icy Monday commute. Right now it looks like 2-3 inches spread out over 2 1/2 days. Temperatures will be above normal Friday and Sunday and below normal Saturday then Monday through Thursday (blue and orange boxes). The GFS (Figure 4) gives us about 1-2 inches from this storm, but SW Denver and the foothills down I-25 to the south may see up to 10 inches in places. The mountains- again- get another foot or more in spots.

Just for fun, I thought we’d check in on the state of El Nino (or ENSO – El Nino Southern Oscillation – Figure 5). The ENSO index is trending towards neutral right now. The southern Pacific isn’t perturbing our weather currently.

Figure 1: The forecast surface map for Friday am from NCEP.
Figure 2: The 500mb forecast upper air analysis for early Sunday morning. Pink dot is Longmont. Red lines are troughs, blue lines are ridges.
Figure 3: the graphical forecast for the next 10 days for Longmont, CO from weatherunderground.com
Figure 4: 10:1 (snow to liquid) snowfall totals through Thursday morning from the GFS and weather5280com for Colorado made Monday afternoon.
Figure 5: the model predictions of the ENSO index from the IRI.
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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 – 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.

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