When will our first snow occur? Enter your prediction for a chance to win! ❄️☃️

5th Annual BoulderCAST First Snow Contest
*CONTEST IS NOW CLOSED TO ENTRIES*

Are you eager for the first snow of the season? Have you already waxed your skis and purchased your Epic Pass? Our first big snow could be right around the corner! We provide a brief overview of Boulder’s first snowfall climatology, discuss the snowfall forecast for the next ten days, and then pose a question…“When will Boulder’s first measurable snow occur this year?” Submit your guess for a chance to win an assortment of prizes. Those who get closest to the date of our first snow win.

First snows of Boulder’s past

September weather is often a bit of a mix bag in the Denver Metro area. Our first snow of the year can and often does occur during the month, but we’ve also seen historic flooding and lengthy heat waves. Hard to believe, right? This is the nature of the business during the transitional months in Colorado. At this point, after nearly eight straight weeks of above normal temperatures, we know you’re tired of the summer heat and just want to jump straight into winter. Let’s briefly review some statistics of Boulder’s annual first snowfall. Hopefully this will give you some context for your contest entry to follow.

Better late than never: A recap of the season's first snow

The chart below shows the date of Boulder’s first measurable snowfall for each year dating back to 1950. Measurable means that officially 0.1″ or more of snow was recorded. As is often the case early in the snow season, a few flakes mix in with rain, or flurries briefly fly, but never stick to the ground. These are instances where a trace of snow has occurred, but wasn’t measurable. For the purposes of the contest, we don’t care about these non-measurable snowflakes.

You can see there is a huge variation from year-to-year in the date of our first measurable snowfall. The earliest was September 12, 2014, with 0.5″ of snow falling. The latest measurable snow was November 26, 1978. That’s a spread of nearly three months! The normal (median) date of our first snow is October 20th.

How about a few percentiles for the gamblers out there? The odds of our first measurable snowfall occurring on or before…

September 20th: 10%
October 1st: 25%
October 20th: 50%
October 31st: 75%
November 10th: 90%

These numbers work out nicely and equate to our first measurable snowfall occurring in September 25% of the time, in October 50% of the time, and in November 25% of the time.

As you might imagine, our first snow event each year is usually a small amount…providing only an introductory taste of winter. The histogram below shows that 37 years since 1950 had an inaugural snowfall less than 2.0″ (54% of the time). Boulder’s first snow only exceeded 6.0″ on 8 occasions (12% of the time). The average amount of Boulder’s first snow is 3.0″, while the median amount is 2.0″.

For the first time ever, Denver International Airport recorded snow before Boulder

Snowfall outlook for early Autumn

With that brief history lesson complete, let’s discuss the possibility of snow in the near-term. How exciting!

This time of year, so early in the season, just about the only way snow can happen on the Front Range Plains is if an epic trough develops across the western United States, spawning a cut-off system that funnels extremely cold air southward east of the Rockies along with some upslope. Taking a look at the last several runs of the GFS and the European models, as well as their ensembles, we’re not seeing much that suggests snow is headed to Boulder through at least the end of next week (Sept 28th). While the wave-train will remain active across the Pacific Northwest and the Rockies, it doesn’t look like Colorado will get much moisture and definitely not enough cold air for snow anytime soon in Boulder. The Mountains above treeline may see light accumulations tonight and/or next week, though.

The Front Range is poised to remain mostly dry with temperatures near or slightly above normal through the middle of next week. While there is a slight chance of showers a few days here and there, chances overall will be slim in the next seven days.

While the next week will be rather quiet and summer-like for our region, things are looking more interesting towards the end of next week. Yes, this eight or more days out and the models are in horrible agreement, but we do see some hints of a pattern shift with the potential for autumn-like temperatures. Both the GFS and European runs and ensembles are showing this potential as a relatively big trough digs across the central Rockies. The below GFS 500 mb height anomaly forecast animation runs through Thursday September 27th. In this particular forecast, the trough near the end of the animation would bring fall-like temperatures and precipitation to the Front Range, but even still would likely be too warm for snow across the lower elevations. Models have been all over the place these last few days in regards to the forecast for next week, so of course nothing yet is carved in stone (or even slightly etched on the surface).

GFS 500mb height anomaly forecast animation for today through Thursday Sept 27th

Looking further down the road, almost all indication from long-range weather and climate model guidance has the next 15 to 60 days being warmer than normal overall across Colorado and much of the United States.

October 2019 temperature (left) and precipitation (right) outlook from the NOAA Climate Prediction Center (updated 9/19/2019)

CFS model forecast anomalies for temperature (left) and precipitation (right) for October 2019

While it only takes one brief shot of unseasonably cold air to give us our first snow, odds are that Boulder’s first flakes may be LATER rather than sooner this year.

Storm Recap: More late May snow in Boulder --- Is it really that rare anymore?

Enter our 2019 First Snow Contest!

Without further adieu, let’s move on to the contest! This is a community poll for the date you think the first MEASURABLE snowfall will occur in Boulder. Those who come closest to the actual date are the winners. For verification, we’ll go off the official Boulder climate station located at the NIST building in south Boulder (FYI, they follow UTC time for date cut-offs).

For prizes, we’re giving away BoulderCAST Premium subscriptions and a $25 Amazon Gift Card.

Among many perks, Premium members get full-access to our daily forecast discussion every morning at 5:00 AM. This is especially useful in the winter, when our meteorologists brain-dump thoughts for days leading up to impactful snowstorms. In case you weren’t with us over the last four winters, we tend to do very well for the entire Denver Metro area (2015-16 Recap / 2016-17 Recap / 2017-2018 Recap / 2018-2019 Recap). Premium members also have admittance to our full suite of weather model graphics, complete 6-day hiking and 6-day ski forecasts, have exclusive access to select content such as video forecasts and weather quizzes.

The prizes for the contest are as follows:

1st place: 12-month Premium subscription + $25 Amazon Gift Card
2nd place: 6-month Premium subscription
Anyone who guesses within 1 day OR 0.1″ correct: 2-month Premium subscription
All other entries: Virtual “pat on the back”

In the event that multiple participants select the same date, the tie-breaker of snowfall amount will be used.

To get things started, here are the dates that some of BoulderCAST Team has placed their bets on:

Ben: October 13th – 1.7″
Andrew: October 19th – 2.0″
Keah: November 1st – 2.0″

Enter you NAME, EMAIL, and guesses for DATE and AMOUNT in the form below on or before Wednesday September 25, 2019. Please only one entry per person.

BOULDERCAST 2019 FIRST SNOW CONTEST ENTRY FORM

*The contest is now closed to entries*

Prizes and recognition will be awarded in the days following our first dumping of snow. Let’s hope it’s a big one!