11/15/05: WIND EVENT / WINTER STORM / BOMB

[Robert Dewey]

Figured I would start a thread for those of us interested in the synoptic aspect of this system (wind, snow, meteorological aspects), versus the pure severe weather threat.

Latest 18Z NAM has this thing down around 975MB, while the 18Z NCEP WRF is down to 970MB... The FSL RUC get's into the sub-980MB region, but all of the data isn't in yet. The 12Z GEM and ECMWF also gets us down to 980MB-ish (979MB).

Meanwhile, latest 18Z GFS, UKMET, and NGM (whatever value it has, LOL) are all around 988-990MB...

As of now, it appears the higher-resolution models are deepening this thing quite a bit... I guess only time and real SFC obs will tell... But given the expected track, I would expect a stronger storm system.

With the expected severe weather and high wind event, here are a few things of interest:

My Weather Station - 2 Minute Temporal Resolution

Webcam (it's choppy, I'm hosting it locally)

 

[Chris Allington]

Precip is beginning to break out over central NE and will move east/ change to snow later tonight... were currently sitting at 38/ 33 here in Papillion will at SE breeze at around 15 mph. A tornado watch is in effect farther to the south across Eastern OK and Western AK... A fairly strong line of storms is breaking out in NW AK at this time with no severe warnings yet but initiation is occuring over many areas in OK and AK...

 

[Jeremy Lemanski]

Even with this being the strongest storm of the 4 so far this nov, DTX says this "" SETUP IS MARGINAL FOR A HIGH WIND EVENT""


This will be a very interesting storm, it will be a game of "how low can it go" So far, it has seemed that the models, the NAM has been the worst, have not had deep enough lows with the past few systems up until about a day or less before the event.

 

[rdale]

It looks like the best setup for winds is going to be more to the northwest this time just like the past few...

 

[Joel Wright]

Can you guys believe how amazingly consistant the models have been with each other with this system? Well at least relatively speaking anyway. I wish they were like this with every storm. Of course I guess that'd make it a little less fun lol.

Everything still looks to be in place for a nice little snowstorm for central IA up into SE MN and NW WI. Because this storm will move so fast it looks like amounts won't get too out of hand, especially with the warm ground. There should still be some impressive snowfall rates even with the warm ground however.

The new morning NAM shows 50-60kts at 850 over much of IA tonight so the high winds still look on target. It's quite possible that the areas hit by tornadoes Saturday will be amidst ground blizzard conditions later tonight, depending on just how much snow falls. I think even though the snow will be relatively wet in nature, with that much wind, I imagine it will be blown around quite a bit...

 

[Robert Dewey]

If this pans out, it could be the 3rd consecutive storm to give me >50MPH wind gusts (EDIT: Okay, NOT consecutive LOL).

The main threat appears to be on the eastern side of the state, where 950-925MB winds are in excess of 50-55KNTS through 15Z WED. Also, cross sections and time-heights show mixing layers getting up around 850MB, with a solid 55KNTS within that layer, and 60-65KNTS at the very top (and over) the inversion. The SFC pressure gradient magnitude actually isn't overly strong, but the 3HR pressure rise just behind the front (or squall line?) over southeastern lower MI is pretty impressive at 5MB (versus the 2-3MB over western MI). I'm actually quite surprised that the NAM SFC windfield is so low considering the parameters... Perhaps there is some nocturnal component in the model that "turns winds down" between 00Z and 12Z (just like the CAPE computation using 70-120M, rather than 2M or 10M based parcels).

I supposed the ultimate reason the NWS (DTX) didn't post a high-wind watch is probably because of the severe weather threat later to day, which should get main priority.

 

[Chris Allington]

Very heavy snow falling right now here in Omaha... alot of it is melting on contact because of high surface temps right now but a fairly heavy band is sitting just to our west moving our way... Winds are starting to blow fairly strong out of the north around 20-30 mph... supercell with reported funnel cloud in IN

 

[Jeff Lawson]

Very heavy snow falling right now here in Omaha... alot of it is melting on contact because of high surface temps right now but a fairly heavy band is sitting just to our west moving our way...

I was surprised when I saw OAX's snowfall tally earlier, with totals clustered around 1". Here in Bellevue, I have a good 3" on the ground. It seems a heavy band sat overhead for much of the morning... the snow was already accumulating well before sunrise.

 

[Mike Peregrine]

Big snowflakes falling in between raindrops in KC now as well. Not expecting accumulation here, but it's fun to get our first taste of winter. An attorney just asked me why these dark clouds are trucking so fast from north to south today. Even the backside of this system looks dark and ominous ... it's one scary day out there.

EDIT - thundersnow coming down hard now ... haven't had it for quite a while here ... the looks on folks' faces is great -

EDIT 2 - Someone just emailed me: "I experienced it in Niagara Falls a few years ago. It’s just not natural. It’s like wrath of God kind of stuff, except that, there’s not even mention of it in the Bible. It’s just wrong. I’m scared."

LOLOL

 

[Tim Gonyo]

GFS has low passing SE of me by about 100-120 miles while rapidly deeping this afternoon/evening. NWS has all rain in forecast for me. I won't be surprised, however, if there is a quick changeover to snow and I get some significant accumulations. Only inhibiting factor, however is 850 temps around 0c. Might be a tad too warm until about 0600z when temps drop to -5c at 850. We'll see I guess.

If this was December we'd be getting 12+ from this.

 

[Mike Hollingshead]

Check out the loop of the Des Moines radar. Must be some nice sleet piling up right where those tornadoes went through on Saturday.

http://www.crh.noaa.gov/radar/loop/DS.p19r...0/si.kdmx.shtml

Dang it I wish I didn't drive a Mustang or I'd head over there.

 

[rdale]

Obs say that is rain...

 

[Mike Hollingshead]

Thanks for the correction...

 

[rdale]

No problem. The radar is probably hitting mixed or frozen precip that is melting aloft, so it appears more intense than it actually is. Somewhat related to "bright banding" if you want to google it.

 

[Mike Hollingshead]

Yeah I didn't even think to look at sfc obs. Just knew it was snowing here and saw that reflectivity and assumed sleet.

http://www.rap.ucar.edu/weather/model/ruc1...hr_sfc_wind.gif

Dang! Haven't seen them packed so tight around here for what seems like years. Seems like 1995 had several of these wind makers and not much since then. That is still 10.5 hours out and looks about the worst near the MO river valley here and up towards sc MN. So far there is only 2-3 inches here and it looks about done. The gust about 30 minutes ago had to be pushing severe criteria. Too bad this snow is so wet or it'd really look interesting out there later today.