Another snow storm headed towards Iowa??

I will certainly tell you that some clippers do dish out tons of snow. The most I go from a clipper was last year, around 12 inches :shock: The system was VERY strong (and very compact), and the angle at which the energy slide through allowed a narrow band (50 miles wide) of 8-12 inch snows, rapidly decreasing outwards.

The way it was handled was interesting. QPF all along was predicted to be around 0.30 inches or so by the models... And since the air was already very cold and the system was coming from a high snow ratio area, I expected a 30:1 ratio or higher... NWS put 2-4 inches in their morning forecast... This was rapidly updated at 11AM as snow was falling heavily (with 3 inches already on the ground) to increase amounts to 3-6 inches with a snow advisory... Another couple hours later, there was 6 inches now on the ground, and the advisory was upgraded to a warning for 8-10 inches or so -- We ended up with 12 inches total. It was the strongest Clipper I can ever remember... Before that, I would have said the max was 4-6 inches...
 
Significant snowfall FCST for NERN IA and SRN MN

For amusement, look at the COD Eta 500mb vorticity loop (US view, 3hr frames). Note how a "ribbon" of positive vorticity is currently approaching the Pacific NW, and later tracks towards the upper-Midwest in NWRLY upper-flow during the next 24 hours. Meanwhile, a strong but compact vorticity center comes crashing SSE out of Canada and merges with the Pacific NW energy over the upper-Midwest between 0Z and 12Z Sat. It looks like the other models (GFS, UKMET) also have a decent handle on this feature too - bill
 
Looks like we well be getting some ice and at least 4 inches of snow tommorow. Actually looking at the data the environment looks a lot like the one that caused the thundersnow two weeks ago in SE SD. Not as much WAA but still promoting a weakly stable environment. There hasn't been to much significant snowfall here so this is welcome.
 
We had an inch of snow here this evening, I took a sample and got a 30 to 1 ratio. Most NWS offices are saying the liquid to snow ratio with this upcoming event will be around 12-15:1, but I don't see them being that low with temperatures barely making 20F...
 
Snow

I'm now hearing that winds could be blowing at 25 to 30mph with gusts to 50mph Friday night and Saturday!, wonder if this could put us in a Blizzard warning situation? Should be interesting.
 
My immediate area is getting screwed again. We're going to get a tiny taste of the storm as usual while our close neighbors get the storm. We haven't even had 10" of snow for the season yet and January's almost over. This is an asinine excuse for a winter here locally.. :roll:
 
Most NWS offices are saying the liquid to snow ratio with this upcoming event will be around 12-15:1, but I don't see them being that low with temperatures barely making 20F...

Although I agree with you that snow ratios will be higher for this system, I don't agree with your reasoning on surface temperatures alone. There are numerous factors contributing to snow densities. The question for extreme eastern WI is how much lake enhancement? Consequently, what effect will Lake Michigan have on snow densities. On an average winter, Milwaukee has a couple of events at most that experience eastern flow during the entire period of favorable synoptic ascent. Should be interesting.
 
Most NWS offices are saying the liquid to snow ratio with this upcoming event will be around 12-15:1, but I don't see them being that low with temperatures barely making 20F...

Although I agree with you that snow ratios will be higher for this system, I don't agree with your reasoning on surface temperatures alone. There are numerous factors contributing to snow densities. The question for extreme eastern WI is how much lake enhancement? Consequently, what effect will Lake Michigan have on snow densities. On an average winter, Milwaukee has a couple of events at most that experience eastern flow during the entire period of favorable synoptic ascent. Should be interesting.

I've always based it on temperatures at the SFC and aloft... But generally, since temperatures decrease with height, the colder it is at the SFC, the colder it is aloft. Storm origin and seeding also play a big role, with southern stream storms averaging a 10-12:1 ratio, while most clippers average 20-30:1 ratios...
 
Upper-Midwest Winter Storm Forecast

Snowfall amounts:
St. Cloud, MN: 5â€-6â€
Minneapolis/St. Paul: 5â€-6â€
Rochester, MN: 6â€-9â€
Waterloo, IA: 2â€-3â€
Cedar Rapids, IA: 2â€, With some sleet mixing in with the snow early
Iowa City, IA: 1â€, With some freezing rain mixing in with the snow early

Timing – onset of precipitation.
St. Cloud, MN: 10 AM CDT, Friday
Minneapolis/St. Paul: 11 AM
Rochester, MN: 12 PM
Waterloo, IA: 2 PM
Cedar Rapids, IA: 4 PM
Iowa City, IA: 5 PM

Discussion:
00Z analysis showed a longwave ridge in the WRN CONUS and trough in the east. Two S/WV’s were embedded in this upper flow – one entering the PAC NW/BC CAN, and the other diving S tough Alberta, CAN. At the surface, a sharp baroclinic zone was noted along from WRN ND through WRN IA to CNTRL IL; with developing low pressure in SERN Alberta. The sharpest pressure falls were occurring in ERN MT, where 3-hr falls of –2.0MB were noted. The 00Z Eta has initialized well to the surface and UA features, and takes a surface solution roughly 40 mi S of the 12Z Eta solution. This is still slightly NWRD and faster then the (12Z) GFS, NGM and UKMET solutions. Eta and GFS are remarkably close with regard to QPF, and I will use a blend of those two for surface and QPF.

Surface low pressure will continue to develop and move to the SE along the baroclinic zone, primarily under the influence of the first S/WV now lifting through SERN BC. It will track through SWRN MN then along the IA/MN border through 00Z Sat. The second S/WV will dive SSE through CAN into MN and then IA early on Saturday. This will serve to enhance QG forcing and UVV’s through SERN MN though 18Z Saturday.

Two methods used for snowfall forecast: PQF and Garcia Method. Use 10:1 snow/water ratio along I-80 for the duration of the event – in fact, there will be a region between 900MB and 850MB above freezing through 06Z, roughly along I-380 in ERN IA. Use 1:15 along the IA/MN border through 00Z, increasing to 1:20 through 06Z, then 1:25 by 12Z Saturday as 850 MB temperatures drop from between –2C and –4C to –20C at the end of the period; and surface tempertures drop from 20-25F to 5F-10F early Saturday. Temperatures between -12 to -16°C through the 900MB – 750MB layer, along with high RH values, are strongly correlated with heavy snowfall – even though amounts in excess of 6†are unusual for clipper systems in the upper-Midwest. Crystal growth rates and aggregation are maximized in these dendrite growth zones. Upward vertical motion in regions of high RH replenishes the supply of supercooled liquid water droplets and thus enables rapid dendrite growth to continue. Finally, Application of the Garcia Method (295K surface, and using 6G/Kg S and 3G/kG N) yields a similar snowfall amount for this storm.

- bill
 
According to GRB we may be looking at 5 inches or more by tomorrow, with gusty winds as well. Winter storm warnings are up...and I have to run errands. :roll:
 
It's sleeting here now. We are going to get about a half inch of snow here, before we get dry slotted very quickly later this evening. A half hour drive to the north and they're going to get about 10". This @##$# sucks man. :twisted:
 
Re: Upper-Midwest Winter Storm Forecast - Storm Recap

Forecast snowfall amounts:
St. Cloud, MN: 5”-6”
Minneapolis/St. Paul: 5”-6”
Rochester, MN: 6”-9”
Waterloo, IA: 2”-3”
Cedar Rapids, IA: 2”, With some sleet mixing in with the snow early
Iowa City, IA: 1”, With some freezing rain mixing in with the snow early
- bill

Snowfall has ended in the upper-Midwest. Some storm totals:

St. Cloud (airport): 5.4"
St. Cloud (State University): 7.0"
Minneapolis/St. Paul (Airport): 5.5"
Rochester, MN: 7" (10+" amounts found within 20mi of this location).

East-Central IA totals: amounts generally around 0.5" along I-80 (Iowa City, where much of the precip. fell as sleet and freezing rain), increasing to around 3.5" along US-20 (Waterloo, Independence).

Cedar Rapids, IA: 1.7"

NWS MPX
http://www.crh.noaa.gov/product.php?site=m...&product=PNSMPX
MWS ARX
http://www.crh.noaa.gov/arx/events/images/jan2205.gif
NWS DMX
http://www.crh.noaa.gov/dmx/coop-plot/Coop...ype=snow&coop=0
NWS DVN - Note also the wind reports here!
http://www.crh.noaa.gov/dvn/ifps/SnowMap/index.shtml

- bill
 
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