Archive for November, 2010

Cold Winds of Change
November 30, 2010

***Watch WISN 12 News for the latest weather information!***

Thank you for stopping by the Weather Watch 12 Blog!  The last day of November 2010 will go down in the weather history of Milwaukee as having a high of 48 degrees, but that certainly will give a poor representation of the day!  A strong cold front but the brakes on temperatures early, and by Tuesday afternoon readings were at or below freezing.

Below is a surface map from around 12:30pm.  The colored in circles that are blue or red represent cloudy skies.  While the ‘*’ symbol is light snow.  Also, the red number is the air temperature, with the green number being the dew point.

On the map below it was 33 degrees in Milwaukee and breezy at this time.  If you look back into Minnesota though, temperatures were only in the teens!

 

 

That cold air is pouring southeast and will not only give us a cold start on Tuesday around 20, but also a chilly afternoon with highs in the upper 20s, and wind chills all day in the teens to low 20s!  So December will start off with some winter-like temps.

I know some may welcome at least a wintry feel, since November didn’t produce anything more than a trace of snow in Milwaukee.  Typically we see the first 1 inch snow around November 30, and the first measurable snow a couple of weeks before that.

There is a chance of snow this weekend.  At the moment it doesn’t look like a major storm, but it may be enough to bring a chance of something sticking.  The models vary in how this little disturbance will play out, but below is the 12Z GFS forecast for Saturday at 6pm.  If this was the case, light snow would be possible, and we can’t rule out the possibility of a mix too.

If you have travel plans on Saturday afternoon into Sunday morning make sure to watch our newscasts for the latest data as the weekend nears.  And look for an update on the weather pattern that was discussed in the winter forecast later this week!

Remember we also post updates on Facebook at WeatherWatch 12 and also on Twitter at WISN12News

Have a great day!

Jeremy Nelson

Rainy November Night…Weekend Storm
November 29, 2010

It may be November, but we are looking at rain and not snow. The heaviest rain will fall this evening with a few light showers/drizzle overnight.  Cold air will wrap in tomorrow, but by that time there will be only a small amount of moisture left. Only flurries are expected. The rain this evening will be moderate to heavy. Rain totals will be between .25″ – .50″. Makes you think it would have been a nice 3-6″ snow if we would have been cold enough. Here is the radar at 7pm.

So far this fall/early winter, the low pressure centers have stayed to our west and north. This has allowed the warm air to bring us rain and not snow. That may change on Saturday. We have our first decent chance for measurable snow this season. The European model and the GFS are now coming into some agreement. This is not a huge storm, but if we have the low track just to our south we could get enough snow to shovel.

Take a look at the two models. Let’s start with the European.

The European model gives us a bulls-eye on Saturday which would mean 3″-6″ of snow. I am not saying this is going to happen. We are still a long way away from Saturday. Now, check out the GFS.

Yesterday’s computer model run of the GFS was not as bullish with the precipitation as today’s. The GFS is much closer to the European solution now. The GFS is also painting our area with accumulating snow. Here is the accumulation product.

The GFS solution would bring about 2″-4″ for us. Stay with weather watch 12 for the latest. The models will be changing as the system gets closer. Thanks for reading.

Mark

Watch out for “black ice” tonight.
November 28, 2010

I hope everyone had a safe and happy holiday. Thankfully, we had great weather for travel across much of the country today and certainly here in Wisconsin. It was a beautiful day with a high of 45 degrees. That was much warmer than the last two days that struggled to reach freezing. The warmer and more moist air may actually cause a problem tonight.

If you have driven on some side roads tonight, you may have noticed a very thin almost invisible layer of moisture/ice on the pavement. You may have even slipped a little walking or in your car. That layer of ice is known as “black ice”. This can be  very hazardous to walking and driving. The thin layer of ice is difficult to see, but can still send your car into a skid or worse. You also must be careful walking because of the slippery conditions as well.

I took a picture of the “black ice” on our parking lot here at WISN-12. Forgive my bad picture-taking with the iphone, but you can see the “ice” parts in the picture surrounded by the areas of just moisture. The areas of biggest concern are areas that were shaded all day. They will be colder than surrounding areas. Watch out on rural roads tonight.

We have the perfect weather conditions that leads to “black ice”. Because of the cold weather the last few days, the ground is now much colder and with the clear skies early tonight, the temperature near the surface cooled quickly. This actually created some condensation to occur as the surface cooled to the dew point which is sitting right around 35 degrees.  As the temperatures cooled a little more, the moisture began to freeze. This is what is creating the slippery conditions. Please use extra caution on the roads tonight and Monday morning.

Once the sun comes out tomorrow, the roads will be fine. Watch out for rain tomorrow night. More on that in tomorrow’s blog and our snow chances for the weekend.

Thanks for reading and be careful.

Mark

Cold Shoppers
November 26, 2010

It was a very chilly start to Friday. Our coldest temperatures of the season arriving on one of the busiest shopping days of the year. I’m not sure if it is dedication or crazy to stand in line for the Black Friday deals. Take a look at the morning lows across the area.

The low in Milwaukee was 18 degrees. This is the first time we have been in the teens since February 26th. The lows don’t tell the whole story. Our wind chills were around or below zero this morning. Our lows tonight will be similar.

The above image is the forecast lows from our high-resolution model. Expect temps to be very similar to this morning. It will thankfully be sunny again on Saturday so that should help make it feel a little warmer. Speaking of warmer, the mild air returns on Sunday. It will be windy again, but the winds will be out of the southwest.  That will help warm us into the low to mid 40s.

The southwest winds will also start to bring in more moisture. This will help lead to a chance of rain showers on Monday. Look for another big cool down on Tuesday. Thanks for reading and have a great weekend.

Mark

From Tornadoes to Teens. What a wild weather week.
November 25, 2010

Happy Thanksgiving from Weather Watch 12. The temps have tumbled today. It is hard to believe that we hit 65 degrees on Monday and highs won’t even get to 30 tomorrow. You have to love Wisconsin weather.

We have not had a chance to talk too much about the tornadoes last Monday, so I want to take an opportunity to recap the rare tornado event.  Two tornadoes hit Wisconsin. One in Walworth county and one in Kenosha and Racine counties. There were only 6 or 7 known November tornadoes to ever hit the state before the tornadoes on Monday. The last time we had a November tornado was November 1st, 1971. We can all be thankful that no injuries were caused by the two tornadoes. I want to show the paths of the tornadoes. The first one hit in Walworth county.

This was an EF1 tornado with a path length of 4 miles with a maximum width of 100 yards. Top winds were estimated at 105mph. Take a look at the doppler radar at the time of the tornado.

The next tornado was the one that hit Union Grove.

The path length was 11.5 miles. The top winds were also estimated to 105 miles per hour. Here is the doppler radar at the time of the tornado.

The image will loop if you put your cursor over the image. The two tornadoes brought our yearly state total of tornadoes to 46. This is the second most tornadoes to ever hit the state in a single calendar year.

Now, on to the cold. Shoppers beware. It is going to be bitterly cold on Friday. Wind chills could be as low at 5 below zero in the morning. Lows will be in the teens overnight and our high will only reach 27 degrees. This is our coldest weather so far this season. Here are the forecast temperatures from our high-resolution model.

I would not be surprised to see single digit lows away from Lake Michigan. The cold lasts through Saturday before we warm back to the low 40s on Sunday.

Have a safe holiday.

Mark

Winter Forecast 2010-2011
November 23, 2010

The most common question that I receive has to be, “What will this winter be like?”.

We will answer that question by using a relatively new weather pattern theory that can help in forecasting our weather out weeks, or months in advance! Let’s start with an introduction to the theory, and then get into this year’s winter forecast!

Back in 2006 I started working at a tv station in Kansas City. The Chief Meteorologist at my station was Gary Lezak. When I started he introduced me to a weather pattern theory he discovered years ago. Once the theory was first explained to me I was the biggest skeptic since it sounded too good to be true and really unbelievable. I was told to follow along for a year, learn, and then form my opinion. I agreed since I was really more curious than anything. After just 3-6 months of watching and studying the pattern, it became very clear that there really was something to this theory.

Back in 2006 the theory was not named, today it is called the ‘LRC’ which stands for Lezak’s Recurring Cycle. Here is what the theory states:

  • A unique weather pattern sets up every year between October 1st and November 10th
  • The weather pattern cycles, repeats, and continues through winter, spring and into summer. Identifying the cycle length helps tremendously when making long range weather predictions.
  • Long term long-wave troughs and ridges become established and also repeat at regular times within the cycle. These dominant repeating features are a clue to where storm systems will reach peak strength, and where they will be their weakest.
  • The LRC is a winter-long pattern! There is a pattern! It isn’t just one long-wave trough, storm system, or ridge. It is a sequence of troughs and ridges that are cycling across the Northern Hemisphere.

To put this in very simple terms, the weather pattern that occurs in October and November repeats thru the Winter, Spring, and into the Summer. The cycle length will vary each year. I’ve seen cycles of 42-46 days, 60-62 days, etc. The easiest way to view the LRC is to look at maps in the middle of the atmosphere, the 500mb level. The 500mb level is really a good spot to analyze the trough(lows) and ridge(highs) positions to help determine the long term longwave ridges and troughs. At the 500mb level you also don’t have to factor in friction or surface moisture. The theory can be translated down to the surface(where we live), which we do in the winter forecast.

After studying this Fall’s overall weather pattern, analyzing countless 500mb maps, and picking out where ridges and troughs reach peak intensity, we were able to put together a comprehensive look at this winter.

A way I like to explain this is to think of a roulette wheel. Once the weather pattern begins to form in early October the wheel begins to spin and the ball is dropped. At this point there is an equal chance of all types of weather, as the pattern is just forming. Once we get to mid-November the ball lands, and our pattern is set and begins to cycle. Where the ball is going to land each year is an unknown. Will it land on a mild and dry winter, how about cold and snowy, or warm and wet?

Let’s start by looking at some of the key features to this year’s pattern. I believe there are 2 dominant features that will drive our weather not only this winter, but through spring and into summer!

Feature #1

The first and likely strongest feature, is a ‘long term’ long-wave trough stretching from Hudson Bay through the Ohio Valley. When this part of the pattern occurs, it will favor fast moving ‘clipper’ systems that will race by bringing Wisconsin light precipitation and shots of frigid arctic air. The cold combined with a northeast wind on the backside of the lows, should give lakeshore areas several chances for quick bursts of lake effect snow. Click to enlarge the map.

This part of the pattern has already occurred in our area. The dominant trough feature showed up on the 500mb map back on November 5 shown below, and other times when we studied the pattern from October into November. This is a feature we expect to see many more times as the pattern repeats.

Feature #2

The second feature produced the massive wind storm that blew through back on October 26. While another storm of that magnitude is unlikely, the position of the ‘long term’ long-wave trough over the Plains and Midwest will support the possibility of stronger and wetter storms. This part of the pattern could bring Wisconsin several chances of precipitation each time through the cycle as storm systems fall into this favored long wave position. This part of the pattern should produce several opportunities for major winter storms!

This feature was revealed during the week of October 26 when a storm system with a record low central pressure slid just to the west of Wisconsin. The result was a major storm, with severe weather, rain, and high winds. As this part of the pattern repeats, I again expect active weather with all types of precipitation possible. The map below is a 500mb chart from October 26 of this year.

As the pattern cycles, there will be other smaller, less dominant features that will provide us our daily weather, but even those are all part of the same cycle.

When putting this forecast together, I also looked at historical data on La Nina winters in Wisconsin, because this will be a La Nina winter. The last La Nina winter was in 2007-08, when Milwaukee picked up nearly 100″ of snow!

La Nina is the cooling of the equatorial Pacific waters. Below is a sea surface temperature and anomaly map from the NCEP site from November 22. This shows the cooler than average waters near the equator in the Pacific Ocean.

While I do believe there may be a La Nina influence to our weather this winter, I firmly believe that the overall weather pattern and cycling of it play a much bigger role than La Nina or El Nino.

Below are snow totals for La Nina winters in Milwaukee. Keep in mind that Milwaukee averages 52.4″ of snow in a typical winter. For our area, La Nina winters have historically produced above average snowfall.  But in the past 60 years, only 6 of 11 La Nina episodes have produced winters with above average snow!

  • 2007-08 99.1″
  • 2000-01 59.3″
  • 1998-99 60.7″
  • 1995-96 51.5″
  • 1988-89 39.9″
  • 1975-76 45.2″
  • 1973-74 83.2″
  • 1970-71 57.3″
  • 1964-65 74.0″
  • 1954-55 39.2″
  • 1949-50 45.2″


After everything we discussed in regards to the LRC, dominant ‘long term’ long-waves, the cycling pattern, and a possible La Nina influence…Here is what we are expecting for temperatures and snowfall this winter!

Temperatures

  • Near Average
  • Multiple below zero readings, something Milwaukee did not record once last winter!
  • A good chance of at least one month having below average temperatures

Snowfall

  • 50 to 60 inches across southeastern Wisconsin
  • 10 to 20 inches more than last winter

Right now the cycle duration(number of days) is still a bit up in the air. Typically we can pin down the cycle length in December. Meaning we should have a very good idea in the next 2 weeks. At this early stage the cycle duration is likely somewhere between 37-45 days. Again, I will narrow this number down in the coming weeks, and begin to make more specific forecasts of when storms may hit our area…weeks in advance!

There are many more aspects to the theory that I’m sure I left out, but that is why this blog is interactive, so you can ask questions and follow along with us. Please feel free to share your thoughts and questions, and I will do my best to provide an answer.

This theory was recently presented at the American Meteorological Society conference, and research continues into proving the theory. While the theory is not perfect, it is the best way I know of to provide accurate long range forecasts weeks, or even months in advance!

I hope you enjoyed the winter forecast!

Jeremy Nelson

The Winter Forecast Tonight On 12 News At 10!
November 23, 2010

The day is finally here!  In just hours the unveiling of our winter forecast for 2010-11!

Here’s a quick sneak peak…

There’s a relatively new weather pattern theory that may unlock the secret of long range weather forecasting.  I first learned of the theory back in 2006 while working in Kansas City.  After a year of seeing how the theory worked, I was hooked!  It allows for the possibility of making accurate long range forecasts weeks, or months in advance! 

Tonight at 10, we will show you what the theory says will happen in southeastern Wisconsin this winter and why!  The best kept secret will then be told, how much snow and cold we are exepcting this winter season!  Once we issue the forecast, we will keep track of the pattern and cycle right here in the blog all winter!

This winter will be fascinating, especially since we are still waiting on our first snowflakes of the season!  It has been an odd Fall with tornadoes in late October, and again in late November!

Below is a picture of a tornado yesterday in Caledonia, Illinois.  This is the same cell that produced a tornado in Walworth County.

What does our warm, dry, and active Fall mean for this winter?  The answers in our winter forecast on WISN 12 News at 10pm!

Jeremy Nelson

From Spring To Winter
November 22, 2010

***Watch the winter forecast Tuesday at 10pm on WISN 12!***

Thank for stopping by the Weather Watch 12 Blog!  We are just one day away from the winter forecast!  We have worked hours on this special piece that will be like no other winter forecast ever shown in Milwaukee!  Here is what you can expect to learn at 10pm Tuesday.

  • A relatively new weather pattern theory is helping to forecast the weather weeks and even months in advance.
  • Find out how the theory works, and hear from its founder.
  • How much snow southeastern Wisconsin is expecting this winter.
  • Whether temperatures will be below average, average, or above average this winter.

Those are just a few of the items that we will highlight during the piece.

For now, the focus is not on winter, but on Spring-like weather in southeast Wisconsin.  Temperatures jumped on Sunday evening to near 60 degrees ahead of low pressure.  Thunderstorms rumbled into the region to kickoff Monday.  And now a second wave of storm could blow through later Monday.

Below is a forecast surface map for 6pm Monday.  A cold front will be slamming into our mild and moist air in southeast Wisconsin.  This should lead to a line of thunderstorms.

With moisture, lift, and shear in the atmosphere, a few storms could be severe.  The Storm Prediction Center has placed our area in the slight risk for severe storms Monday.  Click on the map below to enlarge.

The main threat from the storms would be strong winds, but an isolated tornado(especially in Illinois) can’t be ruled out.  A Tornado Watch covers central and northern Illinois until 6pm Monday.

If severe weather does develop, stay with WISN 12 and Weather Watch 12 for updates!

The surface map from around noon on Monday was incredible!  70s in Illinois, and teens in Minnesota!  The cold air will pour southeast and drive our daytime highs back into the 30s for Tuesday!

Enjoy the mild weather while you can!  Because a taste of winter is only hours away!

Have a great day!

Jeremy Nelson

Thanksgiving Week’s Big Storm
November 21, 2010

Not the prettiest Sunday, but our temperatures were back above average again today. I’m writing this at 6:45 in the evening and our current temperature is 56 degrees. Our average high is 43. We will actually hit 60 tomorrow, but you will have to dodge some raindrops and an isolated thunderstorm can’t be ruled out.

This is one of the busiest travel weeks of the year and of course we have a very active weather pattern this week. Tonight and tomorrow’s rain showers should not cause too many problems. The cold air with this will keep any snow or freezing rain in Minnesota and extreme NW Wisconsin.

Tuesday will be much colder, but quiet weather is expected. The bigger storm arrives late in the day on Wednesday. I have been watching this closely since last week when my cold kept me at home for two days. I’m encouraged by the northward and westward movement of the low pressure with each passing model runs. This would mean more rain for us than snow due to southerly winds drawing in warmer air into Wisconsin. Take a look at three models and there take on the upcoming storm. Let’s start with the NAM.

Note the blue zero line north of our area. That would keep the frozen precipitation north of us. The above image is from midnight Wednesday night.

 

The image above is from the GFS model at the same time as the NAM. Midnight Wednesday night. The zero line is also north of our area.

Finally, the above image is the RPM model. It is from Wednesday afternoon at 3pm. The RPM only is run out to 72 hours. The things to note are the position of the low…well to our west, near Omaha, and the rain area being pushed through much of Wisconsin.

As long as the low stays in this position, and I believe it will, we will have mainly a rainstorm on our hands and not a snowstorm. The cold front will eventually move through cooling us down considerably on Thanksgiving when we could have a few flurries.

Stay tuned. Weather Watch 12 will have updates on this storm all week. Thanks for reading.

Mark

Warmer & Wet(At Times) Sunday
November 20, 2010

***Watch the winter forecast Tuesday at 10pm on WISN 12 News!***

Thank you for stopping by the Weather Watch 12 Blog!  After a cold start to the weekend with highs only in the 30s, a big warm-up is near.  In this entry we’ll look at the first of a series of storms that will hit our area this week. 

The cooler weather was welcomed by deer hunters across the state on Saturday.  That will change today, as a storm will push much milder air into Wisconsin, maybe a little ‘warm’ for hunters.  While it may be a nusiance for hunters, I’m guessing most people will love the warmer weather.  Sunday should be a good day to put up holiday lights/decorations, or finish up some Fall yard work.

Below is the forecast surface map for late Sunday, just click to enlarge.

A warm front will be located just north of our area late in the day.  That means during the afternoon, winds will turn to a more southerly direction, pushing highs into the 50s! While it will be mild, we can’t rule out some patchy drizzle, sprinkles or a few spotty showers.  The periods of damp weather could occur anytime from early Sunday right through Monday!

Another piece of energy will lift northeast on Monday, continuing the chance of showers.  By Monday evening, thunderstorms will line up along a cold front, but it looks like the line may fire right over or just southeast of our area. 

Some rain, or any moisture would be welcomed.  It has been a very dry Fall in Milwaukee.  Here are the updated rainfall totals from Milwaukee’s Mitchell Airport.

Since September 1:  4.37″ (-3.22″)

November 1-20:  0.13″ (-1.76″)

 

Rain totals with the showers on Sunday and Monday do not look heavy, but they may produce anywhere from a few hundredths to over a quarter inch of rain in our area.  Below is a rainfall forecast from our in-house high resolution computer model.

Once we get past Monday, the focus will shift to a potential storm for Wednesday into Thursday.  Still lots of possibilities with that one!  Make sure to watch WISN 12 News for the latest data, and look for additional blog updates.

A quick reminder, we are still working on the winter forecast piece that will air Tuesday at 10pm on WISN 12.  Look for our snowfall and temperature forecasts soon!

Have a great day!

Jeremy Nelson