Meso Low

[Willh]

Could you possibly explain what on earth this spinning low is in the middle of Superior? It's been sitting there n radar for over a day and now they're talking about it coming ashore in the same manner you discuss a hurricane. What on earth is this? I can deduce from the term meso low the basic term...but I've never heard of this.

From MQT:

Strong mesolow is located near Michipicoten Island on eastern Lk
Superior and this is expected to surge southwest toward south
central Lk Superior this morning. Heavy snow and very strong winds
are expected. 3 hr pressure rises of at least 10 mb are expected so
enhancement to gradient winds will result in wind gusts of 40-50 mph
from the north to northeast just in wake of the mesolow. Strongest
winds expected at Copper Harbor this morning and around Marquette
very late this morning into early this afternoon. Given the strength
of lake effect over eastern Lk Superior with radar echoes over 15kft
AGL and higher resolution nighttime satellite showing higher cloud
tops, expect very heavy snow to move in with the mesolow. The heavy
snow along with the 1-2 hour period of 40-45 mph wind gusts will
lead to blizzard conditions. Attm, expect the main impact from
blizzard conditions to be over Marquette. Have messaged this in
the latest winter storm warning statement. However, mesolows can
be highly unpredicable and deliver surprises so the exact location
where most severe conditions occur late this morning into early
aftn may very well need to be refined. Due to the snow/wind this
will produce higher impact. This will turn into more of a nowcast
type situation as we progress through the day.

 

[jd]

Meso lows are small areas of low pressure that form with rising air. Think of it as sort of a hybrid of a regular low and a dust devil or water spout. Much bigger than a water spout or dust devil, but not as bit as your average run of the mill mid-latitude cyclone (low pressure system).

They for when the atmospheric conditions are right for lake effect to occur, but also need the regional winds to be fairly light, so they can create their own circulation. The air converges into the low, many times in bands and within those bands, the snowfall rates are extreme. Usually not less than 1-2" per hour, but can be as high as 5-7" per hour. I have been fortunate enough to experience a few of these and the snowfall is almost surreal it is so heavy. One time I had to cover my mouth to breathe, as the air was so full of flakes, I was choking on the snow just trying to breathe normally!

The low was out in the east-central lake overnight and has drifted south, southwest and is currently hammering the Marquette area and it looks like a feeder band into the low will impact locations from Marquette to Pictured Rocks as well.

You should tune into my radio segment on 93.5 in the mornings around 6:50, as I will talk about such features on air. I did that yesterday, as in yesterday's forecast, it looked like the meso low would hit the Keweenaw and not MQT.

-John

 

[Willh]

Meso lows are small areas of low pressure that form with rising air. Think of it as sort of a hybrid of a regular low and a dust devil or water spout. Much bigger than a water spout or dust devil, but not as bit as your average run of the mill mid-latitude cyclone (low pressure system).

They for when the atmospheric conditions are right for lake effect to occur, but also need the regional winds to be fairly light, so they can create their own circulation. The air converges into the low, many times in bands and within those bands, the snowfall rates are extreme. Usually not less than 1-2" per hour, but can be as high as 5-7" per hour. I have been fortunate enough to experience a few of these and the snowfall is almost surreal it is so heavy. One time I had to cover my mouth to breathe, as the air was so full of flakes, I was choking on the snow just trying to breathe normally!

The low was out in the east-central lake overnight and has drifted south, southwest and is currently hammering the Marquette area and it looks like a feeder band into the low will impact locations from Marquette to Pictured Rocks as well.

You should tune into my radio segment on 93.5 in the mornings around 6:50, as I will talk about such features on air. I did that yesterday, as in yesterday's forecast, it looked like the meso low would hit the Keweenaw and not MQT.

-John

Oh, awesome. I didn't know you did a regular forecast on the radio. I'll definitely be listening to that, then.

What caused all the heavy snow this morning in the Keweenaw (at least Calumet, idk about further north/south)? Went from the moderate like snow we had all night to complete white out. The winds kicked up and everything. I actually took this picture in the parking lot of Pat's in Calumet about an hour ago:

 

[jd]

That was some enhanced snowfall due to enhanced lift caused by converging winds at the surface associated with a shift in the winds from NNW to NNE. Was there around the same time and enjoyed the little burst.

-John

 

[Skylar]

Cool.

 

[Willh]

Ah ok. Thanks for the answer - really cleared it up for me.