Upper-Midwest winter storm on Friday

Winter weather forecast:
Light snow will develop along a New Ulm, MN to Prairie Du Chien, IA line by 6AM tomorrow. Little more then a dusting will result from this initial snowfall event. Through 6 PM, more significant snow will develop along a St. Cloud, MN to Eau Claire line. One to two inches of snowfall will be possible tomorrow evening in those areas. Meanwhile, the “main eventâ€￾ will move in from the west. Moderate to heavy snowfall will move into the southern half of MN by 3AM Friday morning. The snowfall will finally exit the area to the north east by 6AM Saturday.

Storm totals for the event between now and Saturday morning:
St. Cloud: 5â€￾-6â€￾
Minneapolis/St. Paul: 4â€￾-5â€￾
Heaviest snowfall axis: Wahpeton, MN through Baxter, MN: 10â€￾-12â€￾

Discussion:
A warm front will develop along the IA/MN border overnight. This feature will be responsible for some light snow starting early in the day tomorrow and lasting through tomorrow night. Friday through Saturday: stacked low pressure (closed all of the way up to 250mb) will track from Sioux Falls, SD to Duluth during this period. The storm will move very slowly and a TROWEL and deformation zone will set up through MN during the last part of Friday, further increasing the duration of this event. The surface system will rapidly weaken Friday evening through Saturday as it lifts off to the NE. Water to snow ratios should range from 1:8 in SERN MN through 15:1 north of a Milbank, MN to Duluth line. This will serve to keep snowfall totals a bit lighter in the south.

Guidance:
Confidence is low as models have not settled on a solution. In fact, the 18Z NAM places the low track 150 mi SE of the 12Z run. This has brought it closer to the 12Z GFS, ECMWF, NGM, and UKMET solutions.

- bill
 
Yeah no kidding! I've already given up on winter storms. Now it's time for spring.

I hope an active spring can make up for an inactive winter.
 
While most folks head for the beaches for spring break, I headed home (MN)... So, instead of the nice warm weather, MPX has 12+ inches of snow for me tomorrow in the southern Twin Cities metro... Atleast it'll be a doozy I suppose...
 
Got a shovel guys? You can come up and help me scoop out in 24 hrs.

THE NATIONAL WEATHER SERVICE IN SIOUX FALLS SD HAS ISSUED A WINTER
STORM WARNING.

LIGHT SNOW WILL DEVELOP AROUND MIDNIGHT AND BECOME HEAVY AFTER
MIDNIGHT. SNOW MAY BE MIXED WITH OR CHANGE TO FREEZING RAIN FOR A
BRIEF PERIOD SOUTH OF HIGHWAY 34 IN SOUTH DAKOTA...AND HIGHWAY 30 IN
MINNESOTA. SNOW WILL CONTINUE THROUGH FRIDAY AFTERNOON...ENDING
EARLY FRIDAY EVENING. IN ADDITION...NORTHEAST WINDS OF 15 TO 30 MPH
WILL RESULT IN BLOWING SNOW ON FRIDAY. SNOWFALL OF 8 TO 12 INCHES IS
EXPECTED WITH THIS STORM...WITH LOCAL AMOUNTS OVER ONE FOOT POSSIBLE
ON THE EAST SIDE OF THE BUFFALO RIDGE...INCLUDING MARSHALL.

SNOWFALL WILL BECOME HEAVY...WITH 6 INCHES OR GREATER EXPECTED .
VISIBILITIES WILL BE REDUCED SUBSTANTIALLY AT TIMES DUE TO HEAVY
FALLING SNOW OR BLOWING SNOW.
 
Once again, Illinois misses out. You know, I think someone put a bubble over this state. The weather here in Central Illinois has been.... boring. Very dull. Even the clouds are boring.

At least we have blue skies with cumulus clouds, instead of stupid stratus clouds. Not to mention its almost 60F outside already. I'll take this over exciting winter weather anyday.
 
I say no one gets 8 inches...small pockets of 6 maybe. It seems like one of those systems that looks good on the model precip output, but once it starts it will be quite clear it is severely starved for moisture. It is already very dry in the area and the flow doesn't start coming off the gulf till pretty late in the system.

http://www.rap.ucar.edu/weather/model/disp...r42hr18hr24hr30

Ok, now someone gets 2' since I said any of that.
 
Well, I'm all for winter weather until the 2005 storm season begins for the midwest. By the time April arrives though, I am pretty much sick of winter, unless theres a monster blizzard throwing +18 inches at us or the occasional ice storm... Right now though, it's cold, sunny, and boring, so I'll take anything!
 
I say no one gets 8 inches...small pockets of 6 maybe. It seems like one of those systems that looks good on the model precip output, but once it starts it will be quite clear it is severely starved for moisture. It is already very dry in the area and the flow doesn't start coming off the gulf till pretty late in the system.

http://www.rap.ucar.edu/weather/model/disp...r42hr18hr24hr30

Ok, now someone gets 2' since I said any of that.

Actually, it's better to look at isentropic fields for winter weather than a static pressure surface. But, good luck finding those on the 'net. Although I haven't checked the isentropic fields, it looks like the theta-e surfaces may ridge northward from the Gulf to just south of the "snow" region (which is the wind moves northward, is ascending along those theta-e surfaces). Not to mention the tight thermal gradient and strong frontogenesis... This looks like a classic thundersnow situation. There's actually a band that develops from southern MN through WI and into lower MI ahead of the main system for a few hours beginnning 00Z/06Z FRI...

I do think the axis of main snow will be very narrow, but also pretty intense...
 
This storm definitely has enough baroclinicy to work on. It's nearly 60° here right now, while an hours drive north to Dubuque it's snowing and 31°!
 
I say no one gets 8 inches...small pockets of 6 maybe. It seems like one of those systems that looks good on the model precip output, but once it starts it will be quite clear it is severely starved for moisture. It is already very dry in the area and the flow doesn't start coming off the gulf till pretty late in the system.

http://www.rap.ucar.edu/weather/model/disp...r42hr18hr24hr30

Ok, now someone gets 2' since I said any of that.

Mike,
LOL Thanks! Parts of southern MN will likely end up in the 20" category now! There's already nearly a foot of a new snow on the ground across southcentral MN, with heavy snow continuing to fall... The MPX morning AFD has a pretty good discussion on the event ( http://kamala.cod.edu/offs/KMPX/0503181148.fxus63.html )... The northern edge of the snowfall has been very sharp overnight, with a very small distance the difference between heavy snow and no snow.
 
Yep, this is similar to how I chase. "That area really looks bad" "On my way there!"
 
I was hoping for maybe a few rumbles of thunder today. With a current Td of 17°(!!) it's going to have to be all dynamics for any chance at any thunder. That's one bad thing about this time of year. Moisture is usually very hard to come by. Even when moisture does get here, it's usually VERY shallow. There's nothing environmental either to help out, like leaves and anything evapotranspirating. We have to rely soley on advection at this point in the game.

There's some very impressive bands of heavy snow on the north side of this system. There has to be some terrific snowfall rates in some of those bands. What's really interesting is the VERY sharp cutoff to the northern edge of the snow near MSP. It would be interesting to drive south into that. It looks like you would just drive into a wall of snow!
 
Satellite animation of the storm

1-km visible animation (NASA site):

http://www.ghcc.msfc.nasa.gov/GOES/goeseastconus.html

Select "animation",
25 images to loop,
quality=100%,
zoom="high",
map="standard",
map color = "black"

Click on the Sioux Falls area. This may take a long time to load on
a slow connection. Once it loads and starts animating, increase the
speed of the animation a few notches, click "faster" a few times.

An animation like this tells a 1000 words. A few noteworthy
features today: in MN the northern extent of the stratus deck (low
clouds) is seen repidly moving to the west, while the cirrus shield
(high clouds) lifts off to the north east. Note the fresh snow in
the wake of the storm in SD. Note the "dry intrusion" now working
into western IA. Note the high cloud tops developing in north-
central IA and lifting NE towards the IA/MN border. This convection
is a result of very strong upward vertical veloticies as a
result the vort max moving in. Juxtaposed with this is a pocket of cooler
temperatures moving in at the mid and upper levels in association with the upper low. Picture in your mind a moisture "conveyer belt" moving northward through eastern IA and then lifting along the isentropic surfaces from northeastern IA into southern MN. This moisture feed rotates counter-clockwise around the upper-low while continuing to rise (the TROWEL). This is the region of the heaviest snowfall.

- bill
 
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