Archive for July, 2011

Hot Weekend Forecast and Haboob Explained
July 8, 2011

Sorry for no post the last few days. We continue to work on switching our blog to the new format.
Our great July weather continues. Day after day of sunshine. We have earned it after our pretty crummy spring. Some of you are hoping for some rain and you may be in luck on Sunday. What is certain is the return of more humidity and warmer temperatures. It will be sticky all weekend. If you are travelling around the state, here is what you can expect. Saturday will be warm, but dry for much of the state. A slight chance of storms late in the day in the western part of the state.

Sunday will bring a better chance of rain across the state. It will not be as sunny as Saturday. The best chance for storms in Southeast Wisconsin will be late in the day. Don’t change your plans on Sunday because I think most of the day will be dry.

I’m sure most of you have had a chance to see the dust storm that slammed Phoenix last Tuesday evening. This was an incredible storm with winds above 60 miles per hour. Of course, Phoenix is surrounded by desert so those strong winds picked up the dust and sand. The Phoenix area has been very dry, which is typical. This time of year, the monsoon season begins. That means that the desert southwest can get these storms to blow up, especially late in the day. The dust storms are officially known as a “haboob.” The term comes from the arabic word “habb” which means wind. Typically these types of dust storms occur along the Sahara desert. Take a look at this video of someone driving into the haboob on Tuesday evening.

http://www.youtube.com/watch?v=8vQMuwRjI6s

Driving into a haboob can actually be quite dangerous. Visibilities can be near zero. The dust actually rose to over a mile in the air. Here is a picture from ABC News as the storm hit downtown.

Thankfully, we don’t have to worry about haboobs in Wisconsin. It has been dry, but we are way too far away from any deserts. Have a great weekend and stay cool.

Mark

 

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Great 4th, Lake Warming, And Storm Chances
July 4, 2011

Happy 4th of July from Weather Watch 12.  It was a wonderful 3-day weekend of weather. Highs in the 80s all three days. I hope you all enjoyed the great weather.

Jeremy mentioned it yesterday, but we are in our longest streak of the year without measurable rainfall. Today makes 11 days. After many cloudy, snowy, and rainy days for the first half of 2011, this streak has been nice. It is amazing how fast the surface soil dries. We could actually use some rain. We have a chance late tomorrow, but not a great chance. A cold front will move through Wisconsin on Tuesday arriving in our area late in the afternoon. A few storms are possible along the front. We will monitor for a slight chance of severe weather. Here is our high-resolution model for tomorrow afternoon at 5pm.

The RPM model is more liberal in putting in storms than the other models. For those of you hoping for rain, I hope the RPM verifies. I have mentioned this before, but the RPM has a very good track record for a 24 hour forecast. It is my model of choice for a one-day forecast. Here are the NAM and GFS models for Tuesday evening.

I would not count on getting rainfall, but a few locations in our area will likely at least get some rain. The rest of the week looks dry and sunny. Cooler and less humid air will be around Wednesday-Friday.

The sunny skies, light winds, and warm temperatures the last few days have dramatically warmed Lake Michigan. The surface water has warmed more than 10 degrees in one week. When there is light winds, upwelling does not occur. Upwelling is when the cooler waters in the deeper sections of the lake are transported to the surface. This happens when wind pushes the surface water and allows the cooler waters to move upward. Take a look at the lake surface temperature as measured from space.

Keep in mind this is the surface. It is much cooler just a few feet down. Here are temperatures of Lake Michigan for the last five years.

Most of this spring and early summer have been below the temperatures of the last few years. If we continue to have light winds, that could change.

Have a great week.

Mark

Dry Spell Continues, Sprinklers on Standby
July 3, 2011

***Happy 4th of July from the entire Weather Watch 12 team!***

Thank you for stopping by the Weather Watch 12 blog!  Anytime the word ‘dry spell’ and a holiday weekend are mentioned in the same sentence it can only mean good news!

Sunday marked the 10th consecutive day with no rain at Milwaukee’s Mitchell Airport.  That streak will get extended to at least 11 days after the 4th of July.  So we are in the middle of the longest dry spell so far in 2011!

The dry weather on Sunday was accompanied by some high clouds.  The clouds were blown off showers and t-storms over Iowa and Missouri.  Any rain stayed well to our south.  Below is the visible satellite image from Sunday afternoon.  The high clouds are labeled, and so is an area in Minnesota and Wisconsin where skies were sunny. 

Visible Satellite Sunday July 3

The sunshine will spread over all of southern Wisconsin for the 4th of July, and with dew points around 60, and highs in the low 80s, it looks fantastic!  One way to forecast cloud cover is to use the NAM computer model’s water/ice forecast in all levels of the atmosphere.  Keep in mind that clouds are made of water(low/mid level clouds…like cumulus clouds) and ice(high clouds…think cirrus).  When no moisture is forecast in our area as shown by the map below, that should mean a sunny 4th!

NAM Forecast Clouds July 4

With the dry weather and highs recently 80 or warmer, we are beginning to dry out at the surface.  Some rain would be nice this week, but the chances are looking low at this point.  A weak front will near the area later Tuesday and into Wednesday.  An isolated shower or t-storm is possible, but not probably at this point.

The RPM computer model rainfall forecast through Wednesday at 1pm is shown below.  The main thing to take away from this image is that even if it does rain, it may not be much.  Milwaukee is labeled with an ‘*’ on the map.

RPM Rainfall July 6

Overall a quiet stretch of weather ahead, and one that I’m sure most will enjoy.  For now you may want to keep the sprinkler on standby as gardens and lawns may need a drink very soon.

If you have any thoughts or questions please share them in the comments section of the blog.  Have a happy and safe 4th of July!

Jeremy Nelson

Number Crunching & Great Fireworks Forecast
July 2, 2011

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

Thank you for stopping by the Weather Watch 12 blog!  I hope you and your family are having a great holiday weekend!  Weatherwise we lose the humidity for Sunday, but keep most of our sunshine around. 

The good news is there are no storms in the forecast through Monday.  We continue to receive pictures from the storm that hit eastern Racine and Kenosha counties last Thursday.  Tony, one of our bloggers from Pleasant Prairie sent this picture in of the sky as the wind approached at 8:18pm on June 30.

Pleasant Prairie June 30

We’ll talk plenty about the forecast for the holiday weekend in a moment.

First, I wanted to pass along some numbers that I thought were fascinating.  Overall temperatures have been below average in Milwaukee so far in 2011.  But something I noticed really stood out in my mind…the lack of days at or above 80 degrees.  In looking at January through June, there were only 10 days with highs of 80 or warmer.

I discussed this with someone at the NWS in Milwaukee, and found that in the past 37 years, the first 6 months of the year have produced 10 or fewer highs of 80+ only 3 times!  Here are the years…

  • 2011
  • 1992
  • 1974
  • Since 1800s this has occurred 23 times in Milwaukee

That was interesting stat number one.  The second stat relates to the ‘signature’ storm which just impacted our area again in the past couple of days.  This time through the main energy with the low was to our north, but severe weather occurred late on June 30, and then windy conditions both June 30 and July 1.  If you are wondering what is this ‘signature’ storm I’m talking about.  Just click on the link below to find out more about the weather pattern and a review of the summer forecast.

Summer Forecast & LRC Explainer

One result of the ‘signature’ storm almost every time through the cycle has been gusty winds.  The ‘signature’ storm first appeared in late October, and has cycled back 5 more times in the repeating weather pattern.  From late October to July 1 that is a span of roughly 250 days.

In those 250 days, Milwaukee recorded wind gusts of 40mph or greater on 24 different days.  Of those 24 days, 10 of them were during one of the ‘signature’ storms!  This means that about 42% of the wind gusts of 40mph or greater occurred with a storm system that appeared 6 times between October 26 and July 1!  

The ‘signature’ storm will always be the feature that defined the LRC of 2010-2011, but the pattern isn’t done quite yet.  Let’s see if July 19 brings some hot weather back to southeast Wisconsin!

No hot weather in the forecast for the rest of the holiday weekend, but certainly warm.  High pressure is dropping into the western Great Lakes for the next 2 days and with it a lot less in the way of humidity, and also slightly cooler temperatures.

Below is the surface forecast map for Sunday at 1pm.  The big ‘H’ will deliver a nice Sunday.

Surface Sunday July 3

The comfortable weather should hang on into the 4th of July.  The dew points may increase a bit later in the day, but overall dew points should be in the 50s to low 60s…which is hard to beat this time of year.  Below is the dew point forecast map from the NAM computer model for Monday.  Dry weather should prevail in southeast Wisconsin through Monday too.

Dew Point 4th July

With great weather have a blast at the fireworks celebrations in our area!  Make sure to watch WISN 12 News for the updates all weekend long.

Have a great day!

Jeremy Nelson

 

 

Where did the heat go? And More On The Storms
July 1, 2011

A heat advisory was in effect for much of the day, but we never reached heat advisory criteria here. So what happened? We never even made it to 90 and our heat index stayed under 95. The heat advisory was cancelled for most of our counties, but continues in Fond du Lac, Jefferson, and Dodge counties until 9pm.

The reason for missing the heat had to do with thunderstorms that rumbled north to south across Lake Michigan this morning and early afternoon. That brought us some cloud cover, but also kept the wind southeast until later in the day. That kept our temperatures a little cooler and dewpoints stayed in the low to mid 60s. Tonight the dew points are much higher hovering around 70 degrees. Our lows tonight will be warm, staying in the 70s and it will be sticky.

The holiday weekend forecast is a good one. All three days look to have plenty of sunshine. It will be hot and sticky on Saturday with highs in the upper 80s.  A cold front will move through in the morning, but chances of storms will be very minimal. Cooler air will then arrive on Sunday and Monday. Sunday looks great with highs in the upper 70s near the lake and lower humidity. Independence Day will be sunny and comfortable with a high of 80. The weather will be great for all the fireworks and parade celebrations. For a list of all the parade times and fireworks in your area click here:

http://www.wisn.com/entertainment/28322841/detail.html

I wanted to talk a little more about the crazy storms that hit on Thursday evening in Racine and Kenosha counties. Even though little to no rain fell, the storms brought 60-80 mile per hour winds knocking down hundreds of trees and taking out power to over 20,000 customers. In all my years here, I have never seen a storm over Lake Michigan create a downdraft that moved east. It was a very unusual storm. I wanted to show you what the storm looked like in 3 dimensions. It was a very powerful storm.

The storm was over 50,000 feet tall and had a hail shaft that rose to 30,000 feet. That is really incredible for around here.  A big thank you to the National Weather Service for providing the image above. There were some amazing pictures of huge 50-100 year old trees knocked to the ground from the straight-line wind damage. The first one is from Vick Frederick on 13th Street in Racine.

Vick was rather fortunate this did not hit the house directly. The next image was sent to my Facebook page from Amada Aude of Racine. 

The clean up will take a long time. I have talked to quite a few long-time residents from Racine and Kenosha and many say this is the worst storm that they have ever seen. Always remember to stay away from power lines after a storm like this. Treat all of them as if they were live even if they are not sparking.

Have a safe and happy 4th of July weekend from Weather Watch 12.

Mark