We’ve been talking for a while now about the chance to get a “nice” snowstorm by the end of the work week.  As it stands now the area will be affected by a large storm that will contain all snow for a change.  Some other details such as accumulation range are a bit hazy because of the environment the eventual surface low will track.  I’m going to break down the things we are watching as things start to come together in the next couple of days.

First off we are going to take a look at the storm itself.  Yep, you are looking at her.  This dip, outlined by the blue arrows is the key for everything coming together.  The Water Vapor Imagery shows us how much moisture is in the mid levels of the atmosphere, and with that, we can see how the atmosphere is moving.  The dip, meaning there is a pocket of cold air a loft in the atmosphere, will move down the west coast of the United States.   (The land mass directly above the “U” shape is Alaska.)

Wednesday, a Surface low will develop in the four corners region of the United States.  The next few graphics will show how the storm will evolve by the end of the week.  Southern Minnesota and north Iowa will likely see a brief period of heavy snow initially Thursday evening that could last into early Friday morning.  Snow has the chance to continue to fall into early Saturday morning.  The snow, however will be much lighter going forward with the event, and the heaviest snow should fall as the storm starts on Thursday.  We will take a look at why this will happen after the sequence of graphics.

Notice the center of low pressure doesn’t move much from Thursday night to Friday night.  That is because, the atmosphere is in a blocking pattern so the pipeline will be clogged up.  That will in turn make a long duration snow event, but it will also tend to give us lighter precip during the event since the storm will be battling a ridge of high pressure that is blocking things up.  A change in this pattern could cause significant changes to the storm and therefore the forecast over the next couple of days.   The picture below shows the dip that is currently (as of 2/17) near Alaska, now in the four corners and heading towards a ridge of high pressure.  That ridge will act to weaken the low a little bit, but also cause it to stall close to the area, keeping us in the light snow for a long period of time.

As things become a little more clear, we will fine tune tune the details!

Posted under winter, winter weather

As advertised another winter storm is coming this way, but like the last one, it will feature ice.  We will be on the “warm” side of the system that will feature a number of different precipitation types.  Precip should start out as freezing rain for most as the precipitation moves north through Iowa, eventually crossing into southern Minnesota.

Like with the storm a couple of weeks ago, even with the changing precip types, ice will be the biggest factor.  It will likely impact travel through the first half of Sunday, if not even longer.  Salt has issues with freezing rain since the rain washes the salt off the roads before freezing on contact to all surfaces that are below freezing.  The graphic below shows ice accumulations approaching a tenth of an inch of ice, but amounts could be a little higher thanks to road surfaces staying below freezing even when the air temperature is above freezing.

By the mid to late afternoon there will be a better shot to see just plain rain, but take note that untreated road surfaces could still have patchy icy spots through the entire day.  Even though the air temperature may read above freezing Sunday, road surfaces have the potential to be below freezing for much if not all of the day.  The rain, potentially with a few rumbles of thunder will then change back over to snow as colder air enters the storm.  We could pick up an inch or so by early Monday morning.  In case you were wondering, if this was all snow, we would probably pick up around 5-10 inches give or take.  One can dream right?  Out west and north in the warning areas could pick up over a foot in spots.

Posted under winter, winter weather

 While we’re finally enjoying a dry day with a little sunshine in the area today, two commodities that have been lacking in our weather for just about the entire month so far, we’re still looking ahead toward a weekend storm system that may cause some more headaches for us.  Ahead of its arrival late Saturday night, we’ll enjoy a peaceful, seasonably cool Friday with a little more wind and some low 30s for Saturday…basically the calm before the storm.  However, things will begin to get more difficult for us around midnight Saturday night when a little freezing rain is expected to develop ahead of the center of low pressure to our southwest.  We may stick with freezing rain and sleet for the night, possibly until mid morning before warmer air allows us to transition to light rain as temps will be in the mid 30s.  There will still be a chance for some snow at the tail end of the storm system for us by late Sunday evening.  Accumulations may reach three or four inches in some spots locally by Monday morning when things are expected to dry out, but until the system gets a little closer, we won’t be able to pin down exactly who will get what. As you can see below, the heavier snow is expected to be to our northwest as Winter Storm Watches have been issued for a huge chunk of the Upper Midwest in advance of the system. The Twin Cities area is looking at anywhere from four or five inches to seven or eight inches, depending on the eventual track of the storm while areas to the northwest will see higher amounts, possibly as much as a foot in some locations.

Winter Storm Watches are in effect for Sunday to our north and a Blizzard Watch is in effect for western Minnesota and part of South Dakota as heavy snow and strong winds will make travel very difficult in those areas.

Posted under winter weather

If it were colder outside on Sunday afternoon, we’d be dealing with a typical late January snow storm.  Unfortunately things are going to warm up quite a bit, and that will lead to all types of precipitation during the day.  We have the potential to get more ice than snow during the day on Sunday and that will make driving extremely hazardous all day, more so than if it was just straight snow since it doesn’t really matter how good your tires are.  Everything slides on ice.

So here is the breakdown storm wise.  Early tomorrow morning in northern Iowa we will watch for freezing rain to start.  By later on in the morning that precip will move north crossing the Minnesota/Iowa border.  As it is a touch colder to the north,  things may initially start out as snow closer to the border and north before a change over to complete freezing rain.  By about the lunch hour mixed precipitation looks to be falling area wide.

While there may be a period of snow to start, it looks like much of it will fall as a mix or freezing rain.  That will cut down on any snow totals.  The better chance to see accumulating snow will be the farther north you are of highway 14.  With that said, we are still expecting ice accumulations and that is the main reason for the Warnings that are in effect.  Some will see more ice accumulations than others.  Here’s a look at how much can fall.  This will no doubt impact travel significantly, but may also cause spotty power outages across our area thanks to lines and tree limbs being weighted down and falling.

Here’s the mechanism to how freezing rain is created.  On the left side on the picture below there is a picture of a plane, helicopter, and tree.  They are there for height references.  To get freezing rain, you need precip to be occurring.  That precip will start as snow way up in the sky, getting close to where airplanes fly.  Getting closer to the Surface in a freezing rain event,  there is an intrusion of a nice wedge of warm air.  This happens just above the ground, closer to where you would see a helicopter fly.  That warm air will melt the snow flakes into rain drops.  And now the last part of freezing rain.  Below that warm wedge of air lies another cold layer of air.  that cold layer is very shallow and the rain drops don’t have time to refreeze into a snow flake or ice pellet so it hits the ground as a rain drop.  The only problem is, the ground surface is below freezing so that rain drop freezes on contact and you get ice.  You may be wondering how that warm wedge gets above the cold air in the first place.  Well I’m glad you asked.   Warm air is less dense than cold air so the warm air being brought up by a storm system will glide up over the cold air at the surface, since the warm air really can’t move the cold air out of the way.  And that’s how we get freezing rain.

In all seriousness, driving is not recommended at all tomorrow since we will likely be dealing with more ice than snow which will cause extremely dangerous travel.  Be safe and as always send us what you’re seeing on our facebook page or email us at weather@kttc.com

Keep it tuned to KTTC, KTTC.com and like our facebook page facebook.com/KTTCWeather for the latest update and potential forecast changes,  Download our new app for Android and Iphone as well to track the storm.  Search KTTC in the app store.

Posted under winter, winter weather

Here’s the latest on the potent winter storm that is expected to reach our area for tomorrow and Wednesday:

While there are several things that may change in the next day or so, possibly resulting in an altogether different outcome in our local weather, the current forecast outlook for the next major storm system in our region is looking a little warmer and wetter for us.  The latest forecast data suggests that the storm system moving in for tomorrow and hanging around for most of Wednesday will take a fairly northerly track, keeping us in the “warm sector” where rain, sleet, and freezing rain will be the primary concerns while the heavy snow potential will be confined to weather and northwestern Minnesota and for the eastern Dakotas.  Incidentally, some locations in that part of the region will deal with blizzard conditions tomorrow afternoon through early Wednesday as winds will then be reaching 40 miles per hour at times.

Right now, we’re expecting light snow or a mixture of freezing rain and snow to develop in the mid morning hours across the area tomorrow, making for a slippery Tuesday.  Snowfall amounts will be generally light tomorrow with little accumulation if any expected.  The freezing rain concerns will last through the afternoon and into the evening when warmer air aloft will allow for soaking cold rains to spread across the area, making it feel more like April than the last full night of February.  The rain is expected to transition to a wintry mixture or some light, wet snow for Wednesday morning and early afternoon on the back side of the storm system, possibly adding up to an inch or so of accumulation before things dry out Wednesday evening.  The greatest threat for extensive icing in this upcoming storm will be through Tuesday and into Tuesday evening when not only will things be hazardous on the roads, but power outages will be possible.  Overall snowfall totals locally, meanwhile, look to be in more of one to three inch range on theMinnesotaside of the border if in fact snow develops long enough for accumulations to occur.  The Twin Cities will likely see slightly higher amounts of snow, depending on the exact storm track and may end up with as much as six inches and as little as a couple of inches.

The current forecast thinking is for a wetter scenario where our area has lower snowfall totals and more rain and possibly ice accretion in store for Tuesday and Wednesday.

Posted under winter weather

This morning’s latest model data is not looking good for snow in the Rochester and Austin area. At all. There are still watches and advisories in place, and I’m going to assume the NWS will adjust those headlines appropriately after all of this morning’s data arrives, but our first early season snow forecast is looking to be a bust. It hurts. The graphic below is the precipitation forecast from Midnight to 6am Wednesday from this morning’s NAM/WRF model run. It digests its data beginning at 6am Central Standard Time (12 UTC). We call it the “12Z run.” “Z” standing for Zulu time, and the UTC for Universal Coordinated Time.

You can see, at least from this model’s perspective, that snow may clip extreme southeast MN but very little if any would be expected in Rochester, Austin, and Rochester. After 6am Wednesday, the bulk of the precipitation still stays just to our south and east. The following graphic is the precipitation output from another model, one of two primary models we use to forecast out to 7 days. It’s the GFS model, which typically widens the swath of precipitation a bit beyond reality. It would keep us in a bit of light snow Wednesday morning in Rochester and Austin, but would most definitely not indicate amounts over 3″ except for maybe eastern Fillmore, Winona, and Houston counties. At this short of range, I’m less confident in the accuracy of this model over the one in the previous graphic.

Understandably, with all the excitement and anticipation of the season’s first snow, there is bound to be a good share of disappointment in the changing forecast. Snow storms are the most fickle and difficult to forecast, and add that to snow having a more significant impact on more people’s lives than other storm systems, it’s painful to have to pull back the reigns on these snow forecasts.

-Randy

Posted under Uncategorized, winter weather

The final totals, tallies, and thingamajigs are in from the Feb 20-21 winter storm. Here’s a bunch of stuff for you to munch on.

An area of low pressure moved from the southern Rockies into the upper Midwest on Sunday. This system pulled up copious amounts of moisture from the south, and also warmer air aloft and at the surface. The low tracked across Iowa, putting most of Iowa in the rain zone, northern Iowa/southwestern Wisconsin in the freezing precip zone, and much of southern Minnesota in the snow zone. While northern Iowa & southwestern Wisconsin saw mostly freezing drizzle/sleet/rain fall, southern Minnesota saw snow until the midday hours on Sunday, when we lost ice crystals in clouds, leading to the formation of freezing drizzle and sleet. This persisted well into the evening hours before transitioning over to light snow again. By this time, the heaviest band of snow had set up just north of our viewing area, roughly from the Twin Cities west to Aberdeen, SD and east to Green Bay, WI. There, convectice snow led to snowfall rates in excess of 1-2″ per hour. Winds also increased, gusting over 30mph locally, which caused considerable blowing drifting, and, at times, near white-out conditions.

As the main low passed on Sunday night, a lingering wave kept light freezing drizzle and eventually snow falling on Monday, as colder air wrapped in. This allowed most of the area to pick up another 1-3″ of snow…and a crusty glazing of ice.

The following is courtesy of the National Weather Service in La Crosse.

Final totals from the NWS La Crosse warning area – includes sleet, freezing rain, and snow reports. (Note: takes some time to load…not recommended for slow computers…)

Map of snowfall across Minnesota/Iowa/Wisconsin. Note the heaviest fell (bright blues/purples) over central Minnesota into central Wisconsin. These locations saw snowfall rates, at times, in excess of 2″ and hour – they also had some good thundersnow (which produces higher snowfall rates per hour).

 With temperatures close to freezing in our neck of the woods, we saw snow, freezing rain, sleet, more snow, more freezing drizzle, and then more snow. For northern Iowa, most of this came in the form of freezing rain and drizzle, lending to ice accumulations.

Courtesy of the National Weather Service - La Crosse

Courtesy of the National Weather Service - La Crosse

 The freezing drizzle and light snow lingered on Monday, and as colder air wrapped into a lingering wave passing through, our light snow turned extra fluffy. Here are 24-hour reported snowfall totals (just from Monday morning to Tuesday morning – not entire storm):

And here are reported snowfall totals from Sunday AM – Monday AM

And finally, final totals from the NWS Chanhassen office – some spots inched close to two feet of snow!

Posted under snowfall amounts, winter, winter weather

Here are the latest reported snowfall totals to the National Weather Service in La Crosse and Chanhassen.

Some light freezing drizzle will continue today, with some light snow/sleet mixed in at times. Accumulations will be an inch or so. A Winter Weather Advisory remains in effect until 6pm Monday for that wintry mix and light snow that will still cause travel difficulties.

Posted under snowfall amounts, winter, winter weather

Projected final snowfall by Monday PM

9:00pm update: Some light snow and freezing drizzle will take us through the overnight. Totals will be minor for snow, about an inch or so, with up to another inch on Monday. Blowing snow will be common tonight and into Monday. Be safe! The latest snowfall reports are below.

Recently reported snowfall:

3:00pm update:

Warmer air is wrapping into this system, and the heaviest band of snow has shifted north- roughly from Aberdeen to Minneapolis. We will be seeing sleet/freezing rain mix in for south central Minnesota, with some showers for north central Iowa for the remainder of the afternoon and evening. As colder air works back in overnight, it will change over to snow. 1-3″ snow expected tonight, another 1-2″ possible on Monday.

Recently reported snowfall (as of 3 PM)

1:00 pm update : Recently reported snowfall totals

Morning update (updated snowfall predictions below)

- Snow and freezing rain have begun. I’ll try to keep reports updated throughout the day. So far, Owatonna, Albert Lea, and Ellendale are reporting 1-3″ of snow (8 AM hour). Northern Iowa & West Wisconsin (Calmar, De Soto, Oelwein, Osage) are reported a thin glazing of ice from freezing rain (7 – 8 AM hour).

- Winter Storm Warning has been extended to Noon Monday.

- The dreaded freezing line is wreaking havoc on our forecast. It appears the heaviest axis of snow will set up north of Rochester, falling from roughly Mankato to the Twin Cities and into NW Wisconsin (12-16″+ possible there). Lesser amounts south of there. This means more of a mix/ice event, especially along I-90 south into northern Iowa. Snowfall totals, as a result, will be less.

-Snow/freezing rain/sleet today, with more snow than anything tonight as cold air wraps in. Snow continues through Monday morning. The worst of this storm will come today into tonight. Winds will blow around some of the snow.

- Updated snowfall predictions:
North of I-90: 8-12″; Ice: Trace to .10″
Along I-90/ South to MN/IA Border: 4-8″; Ice: .10″ to .30″
IA border south: 2-4″; Ice: .10″ to .50″

Send your pics, reports to our Facebook page, to one of us on Twitter, or to weather@kttc.com!

Posted under winter, winter weather

After a fairly long stretch of spring-like days, we’ve fallen back to more winter-like weather for our Friday with typical February temperatures and wind chills in our area.  The cold front that swept through the region yesterday afternoon scoured out our clouds and fog, but in its wake we have some raw and gusty west winds pulling in this more seasonable air mass today.  With bright blue skies overhead, we’ll likely manage to climb back into the 30s for highs today, but that’s a far cry from the 40s and 50s we enjoyed on Thursday, especially when you factor in those wind chills.  Because of those brisk winds, it’ll feel like the teens and 20s and sometimes even worse when those 30 or 40 mile per hour gusts kick in.  Look for those winds to remain rather blustery through late afternoon when the cold front moves farther away to the east and we lose some of our daytime heating. 

Local high temperatures Thursday afternoon were around 20 to 30 degrees warmer than normal for this time of the year. Areas to the south and west enjoyed the most sun and had the least snow cover, allowing them to see the warmest readings.

Temperatures have fallen off quite a bit today from even the morning readings Thursday that were running mainly in the 40 to 45 degree range. Most spots are 15 to 20 degrees colder this morning than Thursday morning.

We’ll stick with the cooler, more seasonable temperatures for the weekend with dry weather Friday and Saturday before a potent storm system from the west spreads a wintry mixture across the area late Saturday evening, possibly beginning a stretch of 36 hours or so of messy weather in our region.  There will be a chance for freezing rain, sleet, and snow Saturday night with snow and a little freezing rain possible Sunday.  At this time, we’re still trying to determine how warm temperatures will be aloft so we know what type of precipitation types will be occurring and also monitoring the track of the storm, so it’s a little early to say how much snow and ice we’ll be getting from this upcoming storm.  Stay tuned!

Posted under winter weather