FCST: 12/20-12/21 Midwest

[Mark Sefried]

The European model has been consistant with developing a major winter storm over the eastern Midwest for the last couple of days Saturday night and Sunday. Tonights 12z is somewhat impressive and shows a 1001 mb low over Eastern CO at 12z Saturday and it quickly becomes negativly tilted at 996mb as it is forecasted to move east near Chicago at 12z sunday. With that strong of a pacific jet roaring across the nations midsection, systems tend to go further north and be stronger than what the models indicate 4-5 days away. The 12z GFS is now trying to play catchup to the European and is now showing signs of the storm system also. Very Intersting.......

 

[Joel Wright]

Yes it is very interesting. Finally a good negatively tilted storm system. The Euro has been a great model so far this season, but with some factors yet to be determined like additional snowpack I'm gonna take this longer range forecast with a grain of salt. Certainly very interesting. Definitely looks like there could be a big storm later this weekend. It's track is still subject to change I'm afraid.

 

[A Newcomb]

I've been looking at this one the past couple of days, also. It looks to be interesting. although, I don't thing it looks too promising for the Indy area. (I haven't had much time to look) What do you guys think?

 

[Joel Wright]

The 12z Euro still forecasts a powerful winter storm for this time period. Indications of a strong and closed off H5 low could really rev up (or bomb) a surface low over the lower Lakes. GFS shows a much weaker and less phased system, but since the Euro is dominating this winter in overall credibility a stronger solution should definitely be considered. Luckily this is still quite a ways away so there'll be plenty of time to see how things shake up. Either way this one looks quite interesting. Very cold air will be dumping down out of Canada, so this system will have the potential to tap into that.

 

[Bill Schintler]

Winter storm on Saturday

Another in a series of winter storms will bring snow and strong winds to the Upper Midwest Saturday. In Minnesota, the snow will continue through Sunday morning while in Iowa, the snowfall duration will be only a few hours. The main story with the storm will be gusty northwesterly winds starting Saturday evening, resulting in blowing and drifting snow along with dangerous wind chills. Looking ahead, another winter storm will affect the area on Tuesday. The following are forecasts for specific locations in Minnesota and eastern Iowa for Saturday’s event:

Twin Cities, MN:
Snow will start at 7:30 AM Saturday and accumulate to 7.4 inches before ending early Sunday morning.

St. Cloud, MN:
Snow will start at 5:30 AM Saturday and accumulate to 7.1 inches before ending early Sunday morning.

Duluth, MN:
Snow will start at 9 AM Saturday and accumulate to 9.3 inches before ending early Sunday afternoon.

Cedar Rapids (Eastern IA Airport), IA:
Snow will start at 11:15 AM Saturday and accumulate to 1.4 inches before ending early Saturday evening.

North Linn Co. (Paris and Coggon), IA:
Snow will start at 11:00 AM Saturday and accumulate to 1.7 inches before ending early Saturday evening.

Iowa City, IA:
Snow will start at 11:30 AM Saturday and accumulate to 0.9 inches before ending early Saturday evening.

Marengo, IA:
Snow will start at 11:15 AM Saturday and accumulate to 1.1 inches before ending early Saturday evening.

Union, IA:
Snow will start at 10:15 AM Saturday and accumulate to 1.2 inches before ending Saturday afternoon.

Discussion:
WV imagery shows a well defined SHRTWV diving SE through WY and MT. Radar imagery indicates SNWFL in CNTRL and ERN ND in a zone of WAA. The WRF and SREF are depicting this precipitation well. On Saturday, an H85 low will track from ERN ND into the WRN Great Lakes while a sharp height gradient sets up over MN into IA late Saturday into Sunday. At the SFC, low pressure is progged to track from OK into TN during the day Saturday, with an inverted trough extending N into MN. The trough becomes increasingly negatively-tilted as an arctic AMS surges SE from SWRN MN into IA.

Isentropic lift increases Saturday morning along 275-285K SFCs as a TROWAL translates through SWRN MN into WI and mixing ratios increase to 1.0-1.5 k/kg. The WRF is about three hours slower with precipitation onset in all areas then the GFS and SREF, and a faster onset seems reasonable with rapid top-down saturation of the column so I’ll side with the faster GFS. Regarding snowfall totals, all models indicate storm total QPF is around 0.35 to 0.45 inches over MN, with lesser amounts further S in IA. The latest WRF and SREF have trended significantly higher with QPF in CNTRL MN. Snow to liquid ratios range from around 14:1 in IA along I-80 to more then 18:1 in CNTRL MN and nearly 20:1 in DLH. This yields widespread 7-inch snowfall totals over MN and around an inch in ERN and CNTRL IA. A dendritic growth zone depth of nearly 200mb, centered in the 280-285 K SFC or H7-H75 levels, tracks from CNTRL MN into SRN WI. SNWFL rates peak out at nearly 1 inch/hour W of MPX through 15Z with lower rates as the precipitation pushes E.

Wind is a concern with steep LLVL lapse rates of 7-8 C/km allowing for downward momentum transfer of a 50kt LLJ.

- bill

10:33 PM CST, 12/19/08

 

[Joel Wright]

Got about an inch and a half here. Most interesting part of the storm was the powerful cold front that slammed in a few hours ago. Winds were light easterly all day, and are now westerly gusting over 40mph. Temps have crashed from near 30 to 8 degrees in a little over two hours.

Widespread ground blizzard conditions ongoing over Iowa and southern Minnesota. There have been several reports of visibilities well under 1/4 mile. Quite dangerous weather to be sure with temps well below zero combined with high winds and blowing snow!

 

[Josh Richardson]

Widespread ground blizzard conditions ongoing over Iowa and southern Minnesota. There have been several reports of visibilities well under 1/4 mile. Quite dangerous weather to be sure with temps well below zero combined with high winds and blowing snow!

Yep, here in Cerro Gordo County (North Central IA) we've been seeing winds at or near 30 mph all night with gusts nearing 40 mph, we've also gotten about 9 inches of fresh snow in the last two days so obvious blizzard conditions going right now. On top of that the wind chill is -35 right now and probably dropping a little more yet tonight. Travel not advised on any roadway within this part of the state, many roads obviously drifting over.

 

[Aaron Gerhardt]

We had sustained winds of 30mph for a while here in Cedar Rapids, with some gusts just above 40mph during the early evening, we had some shots outside our studio during the 6pm show, was pretty decent. Snowfall wasn't much more than a couple inches, but the blowing snow really made the snowfall look a bit more.

Went out and streamed for this event for the 9 & 10pm show for our station, blowing snow was a big factor in our area (Linn, Benton, Jones counties, Iowa from what we encountered), with some hill crests creating significant blowing snow, and some spotty streams of blowing snow coming off of fields, but was never consistent. Our morning weather guy was in Fayette county reporting about the same conditions. Had many finger drifts covering across secondary north-south county roads, with many being anywhere from 70% ice covered on pavement, to 100% on gravel. Temps were -1 as of 10pm, with wind chills of -25.

Both of our meteorologists doubted the blizzard warning after a while though, at least for our area. It seemed to build up towards the conditions, then the back end of the system had nothing in terms of snowfall to accompany any sustained winds to create any low visibility.

In fact we didn't even see many obs. showing sustained 30mph winds during the event. Our chief met. asked the DVN office on mesonet if they were going to downgrade some counties to just a blowing snow event, but of course they didn't even get back to him until 10:45pm, and we were all packing up at that point. They even asked us to put our video stream back up to give them a first hand observation, but we had long since taken it down.

 

[Bob Hartig]

Here is the view from my apartment in Caledonia, Michigan, seven miles south of KGRR. Photos were taken at 11:30 a.m. for my blog. Thought I'd share them here as well. The sun is out now, filtering through a mist of lake-effect snow. Latest KGRR METAR shows 10 degree temps and WSW wind at 29 miles an hour, with gusts to 35. Tennis, anyone?

 

[Mike Kovalchick]

Earlier this afternoon, I drove South through a rather impressive ground blizzard between US 27 between "Mt. Pleasant" and St. Johns.
It looked like most rurals routes were blocked by drifts with winds out of the West gusting to 45mph. The scene looked like something you would see in North Dakota with snow drifts up to the roofs of cars. Here in the Lansing area, the scene was much calmer but the drifting is creating some interesting patterns in the snow.