Dreary Days & Active Pattern Ahead

***Watch WISN 12 News today at 5, 6, & 10pm for the latest on rain chances!***

Thank you for stopping by the Weather Watch 12 blog!  Make sure to bookmark this link and stop back often…the blog is updated at least once a day and always gives you the inside scoop on the latest weather information.  In today’s blog we are going to look at the active weather pattern ahead for the rest fo this week, and also check out how much rain we are expecting.

After enjoying sunshine and 50 degrees in Milwaukee on Monday…fog, clouds, and rain showers will dominate the forecast for the next 4-5 days!  The reason for the expected dreary weather is a very slow moving upper level storm system.  Since there is really nothing to push this storm out of the Midwest…its effects will be with us into the coming weekend.

The rain showers with this storm could arrive later Tuesday and then continue on and off into the coming weekend.  You can track the rain at anytime right down to your home or office with our interactive radar.  Here is a link…give it a try!

www.wisn.com/irad

Let’s move on and talk about the storm that is headed our way.  The map below shows the 12Z GFS 500mb forecast map.  This is a forecast map showing the position of the storm in the middle of the atmosphere on Friday evening at 6pm.  Notice the large circular rings around this storm…this storm is clearly cut-off from the main flow.  As a result, it will linger for a long time!

 

Now wouldn’t it be nice if this storm could have been forecast weeks ago?  The fact is right here in the blog the March forecast clearly highlighted this timeframe as an active period of weather.  Here is the statement regarding this storm that was part of the March forecast that was issued in the blog on February 26.

March 1-15

The month should get off to a cool start with high temperatures generally between 30-35 degrees for the first several days. Depending on nighttime lows the first few days may be a little bit below average temperature-wise. Closer to the end of the first week highs may be around 40.

The biggest storms during the first week of March should stay closer to the Gulf Coast and also the East Coast.  Another decent snow is possible for parts of the mid-Atlantic or Northeast in the first week.  For Southeast Wisconsin the most active part of the first half of March should occur between March 7-12. If we are going to see a snow of 3″ or more or see some rain/sleet around it would be in this time window.

The good news is that temperatures will be warm enough that snow should not be a concern for our area.  Instead will see several rounds of rain showers.

If you are new to the blog I want to explain something quickly regarding how I am able to make accurate long range forecasts.  Forecasting long range can be very difficult…but the forecasts that I make are based on a weather pattern theory called the LRC.  Here’s more info.

I have been very excited to introduce this theory to viewers here in Southeast Wisconsin. I first learned about the theory 4 years ago while working in Kansas City. 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. Determining the cycle length each Fall really holds the key in using the LRC to forecast into the future. A very good idea of the cycle length is usually determined anywhere from late November thru December. Once the pattern goes thru its second cycle a period of days can be placed on the cycle length.

Now let’s use this theory to do a quick map comparison back to November.  This was the first time through the cycle and also when the jet stream strength was closer to what we are experiencing right now in early March.  Below is an archived 500mb map from November 17.  Comparing this map to the map above clearly shows an almost identical weather pattern at the 500mb level. 

If you are wondering this upper low also formed in January…but did not hang around as long due to the stronger jet stream.

Now that you know how the active part of the pattern was forecast a long time ago…you may be wondering how much rain can be expected.  The models certainly vary on possible rainfall totals with this storm.  But I think almost all areas should see at least a half inch or more of rain this week.

Below is the 12Z GFS forecast from later Wednesday thru Saturday morning.  This timeframe is when the steadiest of the rains may occur.  The map below is color coded.  The light blue shade over Milwaukee indicates 1.00″ to 1.25″.  The purple shade in southwest Wisconsin is closer to 2″ of rain! 

Since this is going to fall over several days I think the threat for flooding should be fairly low.  We will watch this closely because if a quick 1″ of rain would fall there could be some smaller rivers or streams that could see their waters rise quickly.

We will continue to update this forecast throughout the week here on the blog and also on WISN 12 News.  You can also join us on Facebook at WeatherWatch 12   Please feel free to share your thoughts or questions about anything in this blog or about the weather in the comments section.

Have a great day!

Jeremy Nelson

Advertisements

2 Responses

  1. Jeremy, once again the LRC nails it on the head. Indeed this week is active in the weather pattern. Looking at the surface map from November, and then again in March they are almost identical with large areas of low pressure in the Missouri area and another one in Alaska. So because we have such a long stagnating pattern in the atmosphere with mild weather and rain/fog, will this help to thaw the ground out and make future snowfalls melt? Also does this long stretch of midl weather warm up the atmosphere enough to make it less likley that a future storm will be snow? Hopefully these questions make sense. Great job as always.

    • Bryan,

      Snow can stick on the ground all the way into May…at least it has happened before in Milwaukee. The ground warming up will help to get the frost out of the ground. In regards to the atmosphere, the higher sun angle and longer days contribute to the overall warming in the Northern Hemisphere. Snow will be come much less likely the farther we get into April. I’m pretty sure we have not seen our last snowflakes this winter season. Thanks for supporting our blog!

      Jeremy

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: