First Major Snowstorm of 2004/2005

[Tony Laubach]

The Colorado Front Range (mainly the Urban Cooridor) is bracing for a 36 hour snow event which could lead to over a foot, and maybe 2, in areas along the Front Range Urban Cooridor. This includes the Denver Metro Area, Castle Rock, Fort Collins, and areas along and west of I-25.

Last night, snow started falling which has lead to a couple inches at best in these areas, however, NWS thinking that most of the heavy snow will come in later this afternoon and evening.

Chris R and myself PM'd back and forth of our excitement for this storm, and I was even happier to see that my Friday morning forecast of 8 to 12 inches became what NWS started saying later in the day. That morning, they were originally thinking 3 to 6. Here's a quote segment from the discussion I gave in my forecasting lab at school...

The models continue to indicate a decent trough coming in. Taking a quick glance at the 12z ETA, it does show the low further north than previous runs, even as it's still centered over northern New Mexico. The ETA is showing snow over NE Colorado for over 36 hours, and it covers a much bigger area than yesterday's runs. The ETA precip forecast shows over an inch of liquid, which still leads me to believe that the forecasters are underdoing the amounts just a hair. They're thinking upwards of 6 inches; I'm thinking closer to 10 by the time its all said and done. I guess a lot of this will hinge on how long into this storm before it starts to actually accumulate. In any case, I'm thinking DIA will see close to an inch of liquid, which will push up snow amounts for the Metro Area upwards of 10 inches. I'm going to allow the 8 inches to stand for the Metro area as NWS Boulder is saying, but thinking with how the ETA is progressing this, we'll be slightly higher.

The GFS on the other hand really takes its time getting this system in here. Where the ETA is showing the system directly over Northern New Mexico in 72 hours, the GFS still has the system over Northwest Arizona. The GFS shows a tighter low and because of that, has it centered a bit further south than the ETA. The GFS has the biggest area of precip over western Colorado with only about half an inch of liquid. This would correspond with NWS thinking that only 3 to 6 inches are possible.

I'm going to lean toward the ETA with this and say right now that the Metro area will see snow amounts pushing 10 inches, maybe upwards of a foot in some places by Sunday afternoon. This doesn't really take into account any CSI development that could happen in areas; in which case, bump up total accumulations by an inch or so pending the duration of those events. Although the conditions don't warrent direct risk of CSI, it can't be ruled out. I won't bank on any CSI, but if one of those bands does develop, it'll bump up snow accumulations under those bands.

Again, going with 8 to 12 inches for the Metro area; 3 to 6 for the Plains, and upwards of 18 inches for the foothills and mountains. This may change pending the next couple runs, but if nothing else were to be said, this is what I'd go with.

Laubach

I had to post that cause if this verifies, it'll be my first nailed snow storm forecast! This was basically my look at the models. I was also playing around with upslope conditions and all the other stuff. My biggest concern was the position of the low, but that's been a HUGE question all week, and even now, is still slightly foggy, although an agreement looks as if its starting to be made.

I've also stated in this morning's discussion I sent over that I'm going to hold with my snowfall predictions, however, I've also stated that even as I'm thinking 8 to 12 (leaning more toward the 12), I wouldn't rule out higher amounts upwards of 2 feet in places. I'm not going to go out on a limb and say that we'll see 18 to 24 inches, but its something that's possible. Kind of a, I'm not thinking it will, but don't say I didn't warn ya if it does, kind of thing.

Anywoo, feel free to chime in your forecasts on it as many are looking at this system to spawn some severe weather this week. I'd be curious for some input from those more experienced forecasters as I typically enjoy the hell out of forecasting snowstorms and would be thrilled if I nailed this one (on my Birthday none-the-less). 8)

 

[Robert Dewey]

Good potential for snow all the way from your location up through upper MI, which is where I will be. Hopefully I get there in time, before any heavy snow or lake effect snow starts up (which is horrible, the heaviest snowfall rates I have ever witnessesd, sometimes with lightning and muffled thunder). The worst is the wind on the Mackinaw bridge (a 5 mile long suspension bridge going over Lake Huron/Michigan). Winds have been known to gust over 100MPH in intense low pressure systems, but they close the bridge for that. GFS is outputting over 1.25 inches of QPF, which using a 10-1 ration since it's relatively warm, would be a foot of snow. Then as the really cold air pours in over the big lake, that's where accumulations will really pile up. Of course, I am wishcasting for my area, since it's several days out.

Just to let you snow lovers know - Houghton averages over 250 inches of snow per year, which is good for a non-mountanous region.

 

[Robert Dewey]

Happy birthday Tony! I too am kind of bummed out. With the low tracking much further east and being much weaker, the prospects of a good synoptic event over WI/MI area look very slim, and given the rather compact and weaker nature of the low, winds become anti-cyclonic over the snow belts of Superior, and inversions are only marginal at 5K FT... I would say 4-8 inches tops for that area, not the locally two-feet plus that would have likely occured with earlier solutions of the GFS.

 

[Tony Laubach]

Sorry for the late post guys.. and yes, we got robbed here, too! I think I only measured a few meager inches here as well! It kind of sucked.. but hey, at least my forecast went down in flames just like NWS did! :lol: