Archive for August, 2010

Rounds of rain on the way
August 31, 2010

Happy Tuesday. Another hot one with Milwaukee making it to 90 for the 10th time this year. Dew points have been in the low 70s all day. Thankfully, there is a breeze to blow around the hot air.

A line of storms has been holding together all day across Minnesota and western Wisconsin. These are not severe and our well ahead of the cold front, but will still bring rain to much of our area. This will be round one.

You can see there are only a few areas of red on the radar screen at 3:30 PM. These are the only areas with thunderstorms. The rest is a general rainfall. The rain is moving NNE at 25mph with the entire line gradually shifting to the east. I suspect that this line will make it through much of our area, but chances of severe storms is very small. The greater instability (lift from the cold front and jet stream position) is well to our west. The cold front will not arrive until about dawn on Wednesday. Another round of storms may move in at that time, but again this is not expected to be severe due to overnight/early morning stability keeping the storms in check. Here is how it looks on the RPM computer model. We’ll start with 7pm.

The RPM really diminishes the first line. I’m not completely taken with this result. I think that some of the storms will make it to the metro in the middle of the evening.

By 3AM, the next line tries to move into the area. This line is associated with the cold front. Some storms may have heavy rain, but the line should be moving along nicely.

By 5:30 AM, the cold front is just about on top of Milwaukee. The rain showers may hold on early on Wednesday, but the rest of the day should be dry. Thursday is a different story. The cold front will retreat north as a very slow-moving warm front/stationary front. This, along with a strong low pressure center, deep trough, and strong  jet stream will bring another round of storms to the area. Severe weather is possible. The position of the front will make a big difference. If it is able to make it through much of the area and we warm up significantly on Thursday, our weather will have to be monitored quite closely. Furthermore, heavy rain is a possibility on Thursday. Take a look at the forecast rainfall from now-Thursday on the RPM.

If this holds true, parts of the state could pick up 4″ of rain. We will be watching closely. Please stay tuned and have a great day.



Summer Hangs On
August 30, 2010

Please forgive the late post. We hit 90 again today. That makes number 9 for 2010. The warmest has been 92 on Sunday but we have another chance at the low 90s for tomorrow. The breakdown of the 90 degree days goes like this. May: 1. June: 0. July: 4. August: 4.

With the heat and humidity in place and a cold front pushing in late on Tuesday, strong storms are likely in our area on Tuesday night. The timing of the storms may help keep our severe weather chances lower due to the front arriving late at night. The storm prediction center has included parts of our area under slight risk.

There will likely be a line of strong to severe storms that pushes out of Minnesota and Iowa in the late afternoon heading our way. The better chances of severe weather will be in our western counties before the atmosphere becomes a little more stable with nightfall. Take a look at the RPM model of the storms as they arrive tomorrow night.

The above picture is a forecast for 10pm Tuesday night. Note the line of storms to our west.

By 1am, the storms are weaker in SE Wisconsin but still fairly strong to our southwest.

By 4am, the storms are mostly pushing past the area. I would have greater concern for severe weather if the line was arriving in the early evening. However, make sure you keep a close eye on the forecast on Tuesday.

Have a great night and stay cool tomorrow.


Night Sky & Rainy Day(s) Ahead
August 29, 2010

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

Thank you for stopping by the Weather Watch 12 Blog!  As advertised here and on WISN 12 News the weekend ended with highs around 90 degrees.  Sunday was the hottest day so far this year in Milwaukee with a high of 92 degrees!  The late August heat wave will continue early this week.

We’ll get back to the heat and humidity in a moment, but I wanted to spend just a moment on another topic.  Over the past couple of weeks I’ve received some calls and emails about bright objects in the night sky, and what they are.  90% of the time the if the bright object is in the western sky, the answer is the planet Venus.  Recently though, a few other stars/planets have been visible without a telescope.  The planets Venus, Mars, and even a faint Saturn have been visible!

The website Sky and Telescope has some great viewing maps to help out those wondering what they may be looking at in the sky.  Below is one of those maps.  This is the sky coming up on August 31, but for the most part the sky will look very close to this a couple of days before and after the 31st.

If skies are clear any of the next several nights, you may want to look toward the western horizon!

While skies may be clear at times the next few nights, it will be hazy with lots of humidity hanging in the air.  The soupy air arrived in full force on Sunday and will stick around into early Wednesday.  Highs the next couple of days will be around 90, with Tuesday being the hottest day early this week.

Some relief in the form of cooler air and also a chance of rain arrives late Tuesday and Wednesday.  A cold front will slip into our area.  This should produce a good chance of showers and t-storms. Below is the surface map and position of the front on Wednesday morning.  This FORECAST map is valid at 7 a.m. and is from the HPC.  Notice on the far lower right part of the map Hurricane Earl beginning to show up.

With the rainfall deficit at over 2.00″ so far in August in Milwaukee, a little rain will be welcome.  I think anything around 1″ or less should cause few to no problems.  Below is a rainfall forecast thru Wednesday from the 18Z NAM.  The violet and purple shades in southern Wisconsin represent totals of 1.50″ to 2.00″, while the blue and green shades closer to Milwaukee (marked with a ‘*’) are totals of 1″ or less.

Remember, this is just one computer model and one snapshot of the possible rain ahead.  Other models I’ve seen have quite a bit less rain.  I think we will have some showers and t-storms around from very late Tuesday through parts of Thursday.  After that, another comfortably cool airmass will return for the Labor Day weekend!

If you have any questions or comments about the weather, please leave your thoughts in the comments section of the blog!  And make sure to watch WISN 12 News for the latest data! 

Jeremy Nelson

Late Summer Sizzler & Tropical Update
August 28, 2010

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

Thank you for stopping by the Weather Watch 12 Blog!  In today’s entry the focus will be on a developing late August heat wave.  When it arrives, how high dew points will climb, and when rain will drop temperatures.  We will close the blog with a look at a hurricane which may come very close to parts of the U.S. by later in the week.

First, you may hear me use the term 100% sunshine from time to time.  The past several days have fallen into this category with not a cloud in the sky.  Below is a visible satellite image from 4 p.m. Saturday afternoon.  Notice that no clouds were present over the state of Wisconsin.  Safe to say we were enjoying 100% sunshine and a fantastic start to the weekend!

The comfortable 80s with low dew points that covered our area on Saturday, will be replaced by a more humid and much warmer airmass on Sunday, Monday, and Tuesday.  Daytime highs each day will be in the 86-90 degree range.  So don’t be surprised to see a few low 90s sprinkled across southeast Wisconsin in the coming days.

Below is a forecast temperature map for Sunday at 1 p.m.  This map is from the 12Z NAM computer model.  Notice that at 1 p.m. temperatures will already be in the 85-89 degree range for our area!  As long as a slight southeast wind does NOT develop, Milwaukee could touch 90 on Sunday!  Just click on the map to enlarge.

The record high in Milwaukee on Sunday and Monday is 96 degrees.  I don’t think we’ll get that warm, but we will be at least 10 degrees above our average high for the next several days!  And when you throw in dew points of 65-70 degrees, it will feel like the 90s across our region!  Hang in there, September begins on Wednesday!  And remember, by the end of September the average high falls to 67 in Milwaukee!

Our mini heat wave should end on Wednesday as a front will bring a chance of showers and t-storms to the area.

Finally, I want to update you on a tropical system – Earl.  Earl will likely become a hurricane on Sunday as it progresses toward the Leeward Islands.  Any interests along the East Coast of the U.S. will need to keep a close eye on Earl this week.  Just a slight shift to the west, and Earl could bring some nasty weather to the Carolinas!

Below is the forecas path from the National Hurricane Center.  Keep in mind the forecast accuracy greatly decreases past 3 days.  That is why you see a forecast ‘fan’ below.  The hurricane could track anywhere within the white outlined area.  And notice how close this gets to the Southeast Coast of the U.S.!  We will continue to keep you posted on Earl in the coming days in the blog and also on WISN 12 News.

Have a great Sunday and check back here for updates along with our Facebook page at WeatherWatch 12 and on Twitter at WISN12News  Also, stayed tuned to WISN 12 News for the latest data throughout the weekend!

Jeremy Nelson

Rain Stats & Possible 90s?
August 27, 2010

***Watch WISN 12 News at 5, 6, & 10 p.m. for Milwaukee most accurate forecast!***

Thank you for stopping by the Weather Watch 12 blog!  Ever since the July 22 flood that devasted Milwaukee and surrounding areas, it has been almost taboo to wish for rain.  I think we are reaching the point where rain is needed across southeast Wisconsin, and a good half to one inch rain would be welcomed.

So far in August, Milwaukee has only picked up 1.42″ of rain, and there is a good chance this number will not change before the end of the month.  If that is the case, the month of August will end almost 2.50″ below average!

It does seem odd to want rain considering this will go down was one of the wettest summer’s in the city’s history!  Here some numbers I came across from the NWS regarding our wet summer and year.  The first set of numbers is the rank of total rainfall from June-August.  Barring anymore rain, this will be the 2nd wettest summer in recorded weather history!


       Rain      Summer (Jun-Aug)
  1   19.48     1986
 2  19.28   2010
  3   18.11     1885
  4   17.52    1997
  5   17.27    1954
  6   16.35    2008

The next set of numbers is total rainfall this year.  I think before 2010 is over, Milwaukee should easily make it into the top 5 wettest all-time!

     Rain     Year (Jan-Aug)
  1   37.45    1876
  2   32.18    2008
  3   31.93    1960
  4   31.75    2000
  5   31.52    1938
  6   30.82    1999
  7   30.75    1986
  8   30.32    1877
  9   30.12     1990
 10   29.81     1993
 11   28.46     1974
12  28.29   2010

The next chance to add to these numbers will occur very late Tuesday, but more likely on Wednesday.  Remember, I discussed yesterday in the blog how the Atlantic hurricanes may impact the timing of the rain for next week.  To find out how just read yesterday’s entry.

So no rain is in the weekend  forecast, that’s the good news.  The bad news(for some) is that the heat and humidity will creep back.  The first half of the weekend will see dew points in the 50s to around 60, which is still okay.  By Sunday afternoon the sticky air will again surge north and it looks like the weekend will close with dew points close to 70 degrees!

Below is a dew point forecast from the 12Z NAM computer model.  This is valid for 7 p.m. Sunday.  Notice the orange shades over southeast Wisconsin?  That represents dew points around 70. 

So not only will it be increasingly humid, but temperatures will also begin to climb.  Saturday will have a slight wind off the lake, so highs near the lakeshore will stay in the low to mid 80s, with inland areas a touch warmer.

Sunday and Monday are days that could make a run toward 90 degrees.  With dew points not increasing until later Sunday, the dry air will heat up quickly with sunshine and a southwest wind working on it.  I could see a hot end to the weekend with low 90s in spots!  Make sure to watch WISN 12 News to see if I bump highs up to 90 for Sunday or Monday.

One thing is certain, summer is not giving up easily this year!

Have a great weekend!

Jeremy Nelson

Free Air Conditioning & Warm-up Ahead
August 26, 2010

***Watch WISN 12 News at 5, 6, & 10 p.m. for the latest weather information!***

Thank you for stopping by the Weather Watch 12 blog!  Weather conditions the past several days have been almost perfect across southeast Wisconsin.  In Milwaukee highs have been in the 70s, with nighttime lows in the 50s and low 60s.  Combining this with very low humidity, I would say this qualifies as ‘Free Air Conditioning’!

Morning lows were very Fall-like across the state on Thursday morning.  Some spots even dipped into the 30s across northern Wisconsin!  Here is a list of morning lows:

  • Land O’ Lakes  36
  • Burlington  44
  • Fond du Lac  46
  • West Bend  47
  • Sheboygan  48
  • Kenosha  50
  • Milwaukee  56

The low of 56 in Milwaukee was the coolest overnight low since July 1(53 degrees)…almost 2 months!  While the dew points will stay low thru at least Saturday, temperatures are going to begin climbing.

Highs should touch 80 on Friday in Milwaukee, with mid-80s expected for the weekend.  The sunshine will also hang around into early next week, so all-in-all, a nice end to August is on the way.

By Monday and Tuesday, the humidity will once again get your attention, and temperatures may do the same.  Highs are expected to be in the 85-88 degree range both days.  Below is a forecast temperature map from the GFS computer model.  That is valid at 7 p.m. Monday.  Notice that temperatures will still be close to 84 or 85 degrees well after peak daytime heating!  Sunset times by then will be around 7:30 p.m. 

A question mark as to how long the warm weather will last may be tied to something occurring in the tropics!  We are now about in the peak of hurricane season.  And as of this writing, 2 named storms are traveling in the Atlantic.  Hurricane Danielle and Tropical Storm Earl(soon to be a hurricane).  Below is an infrared satellite picture of the storms as of late Thursday afternoon.  An infrared satellite measures the temperature of the clouds, the yellow and red colors represent colder cloud tops, and generally that means they are higher and associated with thunderstorms in this case.  Just click on the image to enlarge.

Both storms in the Atlantic…believe it or not…may impact our weather next week.  The question of how long will our warm-up last, and the timing of a mid-week cold front can be tied to these storms are their paths.  By early next week, a ridge, or area of high pressure will be located over the East.  Since hurricanes are very large, they can act to put the brakes on the overall weather trying to move from west to east.  The storm to watch for next week is Earl.  It will likely become a major hurricane, and could get somewhat close to the U.S.  

Since Earl stands a much better chance of taking a track closer to the U.S. than Danielle, there is a chance the ridge in the East will not move, and the result could be a longer stretch of dry and warm weather for southeast Wisconsin.  So the mid-week forecast for next week will likely change in the coming days to reflect the timing of a cold front. 

Make sure to watch WISN 12 News for the latest data on the weekend and our next chance of rain.

Have a great day!

Jeremy Nelson

Lows In The 40s & 100% Sunshine!
August 25, 2010

***Watch WISN 12 News for Milwaukee’s most accurate forecast!***

Thank you for stopping by the Weather Watch 12 Blog!  If you missed yesterday’s blog showing pictures of VOLLEYBALL size hail, make sure to check it out below this entry.

Today we focus on the refreshing airmass that slid into the area early Wednesday.  Dew points dropped into the low 50s, and air temperatures will be a touch below average the next several days.  Daytime highs will be in the 70s, with nighttime lows in the 40s and 50s.  Yes the 40s! 

Overnight lows in the 40s are not unheard of in August, but only once in the last 5 years has Milwaukee seen an August with lows in the 40s…and that was last year.  On August 31, 2009 we closed the month with a low of 46 at Milwaukee’s Mitchell Airport.

With clear skies and winds easing up tonight, lows will drop into the 40s for inland locations.  Areas closer to Lake Michigan will stay in the 50s.  Below is the temperature forecast for 7 a.m. Thursday morning.  This forecast is from the NAM computer model.  Notice the light green shade over southern Wisconsin, this represents temperatures in the 45-50 degree range.


The cool, comfortable and sunny weather for the next few days is courtesy of high pressure.  Remember high pressure creates a sinking motion in the atmosphere, so this should translate into lots of sunshine. 

On Thursday afternoon, the high should be right on top of Wisconsin.  This should lead to lighter winds and also nearly 100% sunshine!  Below is a forecast satellite map for Thursday afternoon.  The forecast is from our in-house computer model.  The high pressure area is labeled ‘H’.

The dry and sunny days should continue through this weekend.  Highs will gradually climb back into the 80s by Saturday.  Warmer and more humid weather will surge back from Sunday-Tuesday.  Until then enjoy what should be a quick Fall preview!

Remember, new forecast models arrives about every 3-6 hours, and the best way to see the latest data is to tune into WISN 12 News.

Have a great day!

Jeremy Nelson

Record Hailstone & Comfy Days Ahead
August 24, 2010

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

Thank you for stopping by the Weather Watch 12 Blog!  Before we discuss the big weather change headed for Wisconsin, I want to update a story we first brought you in the blog back in late July.

On July 23, a severe thunderstorm pounded Vivian, South Dakota with huge hailstones.  The hailstones were the biggest that many in the community of 200 had ever seen.  It turns out, one hailstone from that storm measuring 8″ in diameter, and 18.62″ in circumference was just verified as the biggest ever recorded in the United States!

The hailstone, the size of a VOLLEYBALL, is shown below.  The picture is from the NWS, and was taken by Les Scott.

The picture below shows the circumference of the hailstone.  Incredible!

While these massive hailstones struck a rural area of South Dakota, there was still extensive damage.  This lady(not sure her name) holds a piece of her roof that one of the large hailstones smashed through that day.  The picture is courtesy of the NWS.

The largest hailstone I’ve ever seen was the size of a baseball while storm chasing in Salina, KS, and that was pretty scary!  Good news for southeast Wisconsin, after a very active summer with flooding, numerous tornadoes reports and endless muggy days, a prolonged stretch of dry and comfortable weather is headed our way.

A cold will sweep across the state today(Tuesday).  As the front moves into southeast Wisconsin late in the day, a few showers will be possible.  No severe weather or heavy rain is expected, but I wouldn’t be surprised to hear a clap or two of thunder.  The timing looks to be mid afternoon to early evening, depending on where you live.

Below is a forecast surface map for 7 p.m.  The cold front will be located near Kenosha, and just east of Milwaukee.  Just click on the image to enlarge.

Once the front clears the area, cooler and less humid will settle in.  I think by Thursday and Friday morning, some inland areas could see overnight lows in the upper 40s!  The dry weather should stick around for the upcoming weekend.  Good news if you are heading to Mexican Fiesta at Maier Festival Park!

That’s it for today, and feel free to share this blog with your friends…I’m sure they’d love to see some Volleyball sized hail!  Watch WISN 12 News for the latest updates!

Have a great day!

Jeremy Nelson

Taste of Fall and a new hurricane
August 23, 2010

A very pleasant Monday to everyone. Another great day in SE Wisconsin. Plenty of sunshine and dew points running in the middle 60s. That is not too bad for this time of the year, but those dew points are about to get much lower. A cold front arrives on Tuesday afternoon. The cold front will have very little convergence so chances for showers and storms are minimal. The cold front will bring a nice refreshing air mass with lows dropping into the 50s and possibly the 40s on Thursday and Friday morning. It will almost feel fall-like for a short time. The rest of the forecast through the weekend and next week looks very nice. An area of high pressure will park itself to our east and that will allow sunshine and beautiful weather.

Take a look at the current conditions.

Click on the above image to make it full size. Note the lower dew points in Montana and Wyoming. For a better look at the dew point temperatures take a look at the contour map.

The cold front will bring the driest air that we have had in our area since May. We have not had lows in the 40s since May and that is likely inland.

On a separate note, a new hurricane has formed in the Atlantic.

The good news is that even though Danielle is expected to become a major hurricane, it should stay away from the United States.

Enjoy our beautiful week of weather. Thanks for reading.


Cooler Weather Awaits
August 22, 2010

What a beautiful Sunday! I hope everyone has had a chance to get outside and enjoy it. Still a little sticky with dew points in the middle sixties, but plenty of sunshine. The northeast wind keeping it a little cooler near the lake, but with the Lake Michigan water temperatures in the 70s, the lake breeze is not like a lake breeze in May when the water temperatures are around 50 degrees. Take a look at the current lake temperatures.

Monday will be a carbon copy of Sunday. Tuesday brings a cold front which will tap into cooler and drier air from Canada. For those of you who are tired of the heat and humidity you will be very happy on Wednesday and Thursday. Dew points will be down to 40s. Almost fall-like. Take a look at the forecast temperatures for Wednesday and Thursday afternoon.

Temperatures in the upper 60s and low 70s around the state for Wednesday.

Thursday morning will likely start near 50 degrees before sunshine warms us back into the low 70s. Enjoy. Thanks for reading and have a great day.