2/20/2005 Winter Storm: Midwest

Well, it looks like another winter storm is possible. Models have been all over the place with strength and location, so pinning down any accumulations of ice or snow is pretty much impossible at this point.

GFS is the farthest north model... The canadian GEM is along the lines of the GFS, with the Regional GEM being pretty strong. The NAM is the farthest south, along with the ECMWF - But, the NAM has been trending northward. Given all of that, the potential for a winter storm appears somewhat elevated.

NCEP's HPC has a low risk for >8 inch accumulations for portions of MI, with a widespread 4-8 inch area from MN to MI and points eastward. Though, I wouldn't put too much faith into any accumulation forecasts at this point.

Our local TV stations have been playing things up for the past several days, and I am at a loss as to why (ratings?). One of the mets stated "This is going to be a really strong storm with the potential for high winds as well as significant snow accumulation"... And that was two or three days ago... I was looking at the NAM and GFS thinking huh?
 
Re: 2/21/2005 Winter Storm: Midwest

Originally posted by rdewey
Our local TV stations have been playing things up for the past several days, and I am at a loss as to why (ratings?). One of the mets stated \"This is going to be a really strong storm with the potential for high winds as well as significant snow accumulation\"... And that was two or three days ago... I was looking at the NAM and GFS thinking huh?

Remember that TV stations have their own definitions of significant snowfall. I grew up in Ohio where a TV station inch was actually a centimeter. Since growing up with that, I've learned to take TV stations with a grain (inch) of salt.
 
RE: Midwest winter storm - Eastern IA forecast

Winter weather forecast for east-central Iowa:

A light rain and snow mixture will start in the Iowa City area around 5 PM Saturday and in Cedar Rapids by 7 PM. Precipitation will increase in intensity throughout the Saturday night and Sunday. About 0.5 inches of snow/slush will accumulate in Iowa City by Sunday morning before the precipitation changes over to all rain by 8 AM, melting the snow. Cedar Rapids will see 1-2 inches of the white stuff before precipitation changes over to all rain by 9 AM Sunday. Areas to the north, along US-20, will see about 3 inches of snow before a changeover to rain by 10 AM. Rain will end or change over to flurries by 5 PM Sunday, with liquid totals of around 0.4 - 0.5 inches.

- bill
 
Re: 2/21/2005 Winter Storm: Midwest

Originally posted by Tony Laubach+--><div class='quotetop'>QUOTE(Tony Laubach)</div>
<!--QuoteBegin-rdewey
Our local TV stations have been playing things up for the past several days, and I am at a loss as to why (ratings?). One of the mets stated \"This is going to be a really strong storm with the potential for high winds as well as significant snow accumulation\"... And that was two or three days ago... I was looking at the NAM and GFS thinking huh?

Remember that TV stations have their own definitions of significant snowfall. I grew up in Ohio where a TV station inch was actually a centimeter. Since growing up with that, I've learned to take TV stations with a grain (inch) of salt.[/b]

I was just listening to the local radio station (950 WWJ), and they said more than 6 inches is possible (They have an Accuweather met do the forecast). At this point, I'm not even understanding why they are forecasting amounts. The models have been all over with strength and location. Latest GFS has nearly 1.25 inches liquid equivalent in some areas where all snow is expected (southern WI), meanwhile the NAM only has 1/4 of the amounts the GFS does.

A few more runs should definately help things out a bit...
 
Wow... Had a few rumbles of thunder in the past 30 minutes, with visibility below 200 feet. I can't even see the neighbors house... This is the most intense synoptic scale snowfall rates that I can remember witnessing (lake effect doesn't count)...
 
It wouldn't be synoptic snow if falling during convection. Picked up about 3-4" around here, on the bottom edge of my forecast range but I'll take it. Didn't want to be lumped in with the 5-9" busters from earlier this week ;>

- Rob
 
We got a whole half inch here last night. Our total for the season is fast approaching 13"!!! Wow, what an impressive year for snow this has been!! :x
 
It would be great if those of you experiencing thunder snow could make a report with all the details to help assist with our convective snowfall forecast verification on the following website.

http://solberg.snr.missouri.edu/ROCS/particip.html

Details on the ROCS (Research On Convective Snows) can be found on the website as well if you are interested in the project.

Thanks,
Dan Hinch
 
Originally posted by rdale
It wouldn't be synoptic snow if falling during convection. Picked up about 3-4\" around here, on the bottom edge of my forecast range but I'll take it. Didn't want to be lumped in with the 5-9\" busters from earlier this week ;>

- Rob

Well, my intention was to show that I have seen heavier snowfall rates, but only when other mesoscale factors (lake induced) are at play. What I meant by synoptic was that the system is basically driven by warm advection, isentropic ascent, etc.. Granted, lake effect snow is convective as well - So I guess technically they could both fall into the same catagory?

We have about 6 inches on the ground here. The very heavy snow, with thunder, lasted about 15 minutes. It would have been great if we could have had that during the night, for a solid 6-12 hours :lol: (nor'easter style).

Radar looks interesting... L2 data is showing a very cellular look to precip, so my guess is that isn't snow, more likely sleet and freezing rain - Which is headed my way.
 
I ended up with a 1/2 inch of snow, to go along with a nice hazardous glazing of ice that occured late last night. Most of the snow has no melted and we are left being very soggy. Not to much to be greatful for, waiting for the spring storm season seems better and better... ;)
 
"Well, my intention was to show that I have seen heavier snowfall rates, but only when other mesoscale factors (lake induced) are at play"

I see - I've never experienced anything worse than the whiteouts in our blizzardish thunderstorms while I wouldn't refer to that as synoptic snow. We're primarily rain right now, a bit too warm for any freezing issues.

Incredible how the dbZ resolution with L2 showed a much better picture than L3 today with the banding!

- Rob
 
some of the highest totals came from alma and mount pleasent both with 14 inches and some spots near 15. Seems a little high, but i guess it could happen with the type of setup we had. picked up around 6-7 here, maybe another inch yet to go before its done.
 
I had a hard time believing those numbers (fortunately I made my snowfall map before they came out so I didn't talk about them much on-air ;> ) but in reviewing the Level II imagery there were some impressive bands going on for a while up that way.

- Rob
 
Originally posted by rdale
I had a hard time believing those numbers (fortunately I made my snowfall map before they came out so I didn't talk about them much on-air ;> ) but in reviewing the Level II imagery there were some impressive bands going on for a while up that way.

- Rob

Yeah, I was watching those bands all afternoon. It does appear that some areas remained within heavy snow bands for quite some time, and as the old bands drifted off, new bands formed. I wouldn't quite say 14 or 15 inches, more like a 10-12 inch snowfall. Given the low snow to liquid ratio and compaction - If 15 inch amounts were actually realized, liquid equivalents would have likely exceeded 1.50 inches :shock:

This was a very good overrunning situation though... I did some isentropic analysis with the ETA 212 data, and the low level jet (850-700mb) intersected the pressure surfaces at a right angle, which is perfect. Lift was very impressive (omega's off very high)... Also of interest to me, was this system had a very strong TROWAL between 700-500mb, right over the area of heaviest snow - While this alone isn't impressive, when combined with very intense vertical motion, weak stability, and high moisture, historically leads to significant snowfall events. Within that region, theta-e cross sections showed the atmosphere to be convectively unstable, which was obviously realized...

Even though I didn't wind up with a ton of snow (6 inches), it was very interesting watching the situation pan out...
 
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