Seasonal Totals (Fall 2019 – Spring 2020):
- Measured: 123.5″
- Estimated: 5.1″
Continue reading “Snow Measurements (Fall 2019 – Spring 2020)”
NOTE: Entries are in reverse chronological order. This page does not automatically update.
- 4/13/20 3:50 PM
Winds continue drifting westward, shutting down lake-effect snow production. We’ve had no measurable snow since 12 PM. Humidity has dropped to around 65%. This should spell the end of our snow storm. I see that the National Weather Service has pulled down the Winter Storm Warning that was supposed to last through tomorrow morning. Gusty winds should subside over time, especially after sunset. But do mind the lakeshore flood warning and stay clear of Lake Superior as it takes some time to settle down after winds abate. Anyway, that ought to do it for our live blog. Again, our storm total was 17.2″ as measured 1 block north of the Jacobetti Veteran’s Home near downtown Marquette.
- 4/13/20 2:45 PM
Some light flakes continue to fly but nothing significant. The focus now is on the wind. Even as the trough of low pressure crosses into Quebec, it continues to deepen, drawing air from areas of higher pressure, such as Marquette, toward it. How big is this system? Well, it has 5 frontal boundaries extending from it, including 2 cold fronts stretching down into the Gulf of Mexico!
- 4/13/20 1:15 PM
After declining for about 4 hours, winds have kicked back up in the last hour as the surface low exits the region. Gusts nearing 35 mph have been observed here. Snowfall has tapered off to light snow showers as winds have turned solidly to the northwest.
- 4/13/20 12:20 PM
Light snowfall. Latest measurement (10 AM – 12 PM): 2.1″. Event total: 17.2″
- 4/13/20 10:00 AM
Moderate snowfall. Visibility 1/4 – 1/2 mile. Snowfall measurement (7 AM – 10 AM): 1.2″. Event total: 15.1″
- 4/13/20 9:30 AM
Some lake-enhanced snowfall could set up soon, lasting at least into the early afternoon hours. Conditions are somewhat marginal, so not expecting too much additional if the lake gets involved. Knock on wood because this is spring in the U.P. and Mother Nature likes to take a shot at us this time of year. Currently less than 1/4 mile visibility due to blowing snow.
- 4/13/20 8:55 AM
Looks like we’ve bottomed out in surface pressure. Our gauge recorded 998.7 mb (29.49″) MSLP at ~ 7 AM EDT. The center of the low is located near Sault Saint Marie. It should slowly march NE into Quebec this afternoon. We should be nearing the top of the mountain in terms of winds within the next hour or two (if we haven’t arrived already).
- 4/13/20 8:25 AM
Moderate snowfall continues. Visibility is generally 1/4 – 1/2 mile but localized blowing snow creates near whiteout conditions at times. Gusty northerly winds (30-35 mph gusts) continue to buffet the city.
- 4/13/20 7:30 AM
Winds continue to ramp up over the last several hours. The peak wind gust measured so far here is 34 mph but 40 mph does not seem not out of reach by later this morning. Fortunately, the moderate to strong winds throughout this storm have kept power lines free of snow.
- 4/13/20 7:00 AM
Moderate snowfall. 1/4 – 1/2 mile visibility. Snowfall measurement (9 PM – 7 AM): 8.2″. Event total: 13.9″
- 4/12/20 9:00 PM
Moderate snowfall. 1/4 – 1/2 mile visibility. Snowfall measurement (6 – 9 PM): 3.6″. Event total: 5.7″
- 4/12/20 7:45 PM
Heavy snowfall continues. Visibility between 1/8th – 1/4 mile. Next snowfall measurement at approximately 9 PM.
- 4/12/20 6:05 PM
Visibility has dropped to approximately 1/8 mile due to heavy snowfall. 2.1″ measured so far.
- 4/12/20 5:30 PM
Snow is beginning to stick to roadways too now. Visibility is just over 1/4 mile.
- 4/12/20 4:05 PM
Snow is beginning to stick to grassy areas around our property now. Cement is wet but free of snow.
- 4/12/20 3:25 PM
Initial snowfall this afternoon has been melting on contact due to the relatively warm ground, but temperatures have been falling over the past couple hours.
- 4/12/20 9:00 AM
Expect the snow to start flying by mid afternoon. Heaviest snowfall after 8 PM. Winds should stay light to moderate until daybreak Monday. Winds will build after that point reaching a peak in the afternoon. Blizzard-like conditions are likely as it will be snowing all day Monday. As per usual, I will report periodic measurements & observations here throughout the event. Keep checking back.
You may wonder, “How can it snow & drizzle at the same time?”
Short answer: when clouds aren’t cold enough to produce snow (exclusively or at all) drizzle can form.
Longer answer: If the air is sufficiently cold and wet, only snowfall is possible. But when precipitating cloud top temperatures are above -10° C (14° F) but still below freezing, the ice nucleation process requires help. Unstable, rising air can induce the formation of snowfall. Failing that, with only slightly below freezing temperatures, snow crystallization needs smoke, dust, pollution or any other tiny airborne surface upon which to bond. Otherwise precipitation can fall as drizzle/mist.
Why today? We’ve had a shallow layer of moist, sub-freezing air (< 5,000 ft) “capped” by warmer, drier air above since Sunday evening (1/26/20). Cloud tops have been just below -10° C. The moist air from sublimating snow/ice and weak low pressure has combined with onshore, upslope winds to induce some lift in the lower atmosphere. This, along with whatever particulates were aloft, produced snowfall. The remaining moisture has fallen as drizzle which froze upon contact depending on the surface composition. Most surfaces weren’t cold enough to allow much, if any, ice accumulation. A light glaze has been observed in places around our property — just enough to increase stopping distances on untreated pavement.
Normally this time of year clouds are much colder. But we have been running well above normal throughout the atmosphere recently. That’s why we’ve had several wet snow events in December & January.
I normally don’t allow “Winter Weather Advisories” (WWA) to post on the City page (home page), because too often those end with unremarkable snow totals here. Also, people tune out after a certain point if they are constantly barraged with alerts, which can happen during the winter here. When you see an alert posted on our main page, you can generally place confidence in its importance and relevance to the city. Note that the detailed forecast will always specify accumulating precipitation within the next couple days regardless of alert status.
When I saw the Winter Weather Advisory hoisted on Friday (1/17/20), I decided to post it. I could see that just the front-end of the incoming storm was forecast to deliver 4-7″ in about 12 hours. I could also see that conditions were right for a decent amount of lake effect over the following 24 hours. The $64,000 question, as always, was “how much?”
Continue reading “Revising Alert Policy”