Heat Wave of July 9-10, 1936

The Dust Bowl years of the 1930s brought on some of the hottest summers on record across much of the United States.   For much of the Upper Mississippi River Valley, the first few weeks of July proved to be the hottest temperatures of that period, including many record setting highs.  The string of hot weather also proved to be a deadly one with around 5,000 deaths nationally.  Temperatures of over 100° were very common across much of the Great Lakes and out East.


There were several factors that led to the deadly heat wave of 1936:
- A series of droughts effected the US during the early 1930s
- Poor land management across the Plains increased the impact of the drought
- Without any of the vegetation and soil moisture, the Plains really heated and almost took on desert qualitites
- A strong ridge of high pressure on the west coast kept the heat streaming in across the Upper Midwest and Great Lakes.

(source: National Weather Service, La Crosse WI)

Urban Heat Islands

While I was making some final touches on tonight's 10:00 show during our first commercial break (just before weather), I noticed that Minneapolis-St. Paul had a 10pm temperature of 78 degrees, while Rockford was down to 76. They were 2 degrees warmer than us despite having some breaks in the overcast (we were cloudy), being almost 3 degrees latitude further north than we are, and having sat in that post-frontal cooler air for as many as 6 hours longer than we have.

So why were they warmer than us? I'm pretty sure it's because of the urban heat island effect. Minneapolis-St. Paul is a much larger metropolitan area than is Rockford. There is a lot more concrete, asphalt, and a lot more buildings to catch and absorb the sun's incoming radiation and then release it at night. Furthermore, the Rockford airport is located on the edge of town while the MSP airport is located in the heart of the Twin Cities metropolitan area.

This urban heat island effect is partially why so many people who live along the east coast with this latest heat wave are suffering. Big cities are generally hotter! Especially at night.  --TS

Tornado touches down in Columbia County Wisconsin

9PM Thursday Update: 
Results of the Columbia County Damage Survey

Strength: EF1
Length: 4 Miles
From 2.5 Miles SW of Cambria to 2.1 Miles ESE of Cambria
Max Width: 125 Yards
Time: 6:27 pm to 6:41 pm - July 7th, 2010
PUBLIC INFORMATION STATEMENT

NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
903 PM CDT WED JUL 7 2010

...TORNADO OVER NORTHEAST COLUMBIA COUNTY...
A QUICK-DEVELOPING THUNDERSTORM SPUN UP A TORNADO IN NORTHEASTERN COLUMBIA COUNTY EARLY WEDNESDAY EVENING...JULY 7TH.

IT STARTED ABOUT 627 PM ABOUT 2 MILES SOUTHWEST OF CAMBRIA WHERE IT DAMAGED OR DESTROYED TWO BARNS. OTHER DAMAGE WAS NOTED IN THE STH 146 AND CEMETERY ROAD AREA SOUTH OF CAMBRIA...BUT THE EXACT NATURE OF IT IS UNKNOWN AT THIS TIME.

BASED ON WSR-88D DOPPLER RADAR....THE TORNADO TRACKED EAST-NORTHEAST THROUGH THE AREA JUST NORTH OF CEMETERY ROAD. HOWEVER THE EXACT ENDING LOCATION IS UNKNOWN. THE CENTER OF ROTATION ON RADAR...KNOWN AS A MESO-CYCLONE...TRACKED TO JUST NORTH OF RANDOLPH BY 652 PM AND THEN TO JUST NORTH OF FOX LAKE IN NORTHWEST DODGE COUNTY BY 710 PM.

NO ADDITIONAL REPORTS OF DAMAGE WERE RECEIVED FROM THE RANDOLPH AREA OVER TO THE FOX LAKE AREA.

A DAMAGE SURVEY WILL BE CONDUCTED BY THE NATIONAL WEATHER SERVICE THURSDAY MORNING AND AFTERNOON IN NORTHEAST COLUMBIA COUNTY AND NORTHWEST DODGE COUNTY IN CONJUNCTION WITH EMERGENCY MANAGEMENT OFFICIALS. THE SURVEY WILL HELP US DETERMINE THE STARTING AND ENDING
TIMES AND LOCATIONS OF THE TORNADO...AND ITS EF-SCALE RATING.
IF YOU HAVE ANY RELATED DAMAGE REPORTS...PLEASE EMAIL THEM TO...
w-mkx.webmaster@noaa.gov

Tropical Depression #2

Several observations indicate that the low level circulation of Tropical Depression #2 is not well organized and is just moving on shore in extreme southern Texas.  Since this system is currently on land, further strengthening is not expected and the primary threat is heavy rainfall.  Unfortunately the rain is forecast to occur on top of already saturated ground and high rivers across parts of southern Texas and northeast Mexico caused by hurricane Alex.

Heavy Rain Potential

So far, the Stateline has been fortunate enough to miss-out on the heaviest rainfall amounts. Some areas in eastern Iowa and southeastern Wisconsin have seen 1-2" of rain today. In fact we did see one total over 3"... 6 miles west of Kenosha, WI, 3.52" of rain fell in about 90 minutes!

Overnight into Thursday morning, our luck may run out. Hopefully, the 3" totals will elude us. But 1-2" totals are definitely within the realm of possibility as a cold front approaches us from the northwest. This front will finally provide more focus for organized rain and thunderstorm development. Thursday afternoon, our rain chances will gradually taper off. Then expect a mostly-dry weekend (with the possible exception of Sunday evening).  --TS

We Want your Feedback!

The weather blog has been up and running for about 6 months and I want to know what you think of it.  What do you like...what don't you like?  What would you want to see more of?  When severe weather moves through, do you find the weather updates and reports informative?  Let us know how we can better improve our weather to bring you the best coverage in the Stateline!

Aphelion - Earth Furthest from the Sun

July 6, 2010, is the date of our annual "aphelion" -- the time of year when the earth is furthest from the sun. That's right... It's the northern hemisphere's summer, and we are FURTHER away from the sun on this date than we are at any other time of the year! We're 94.5 million miles away from the sun, to be exact. On January 3rd, we are "only" 91.4 million miles away from the sun. This time of year is called "perihelion."

The reason we are warmer at this time of year than in January is because the northern hemisphere is tilted towards the sun's direct light at this time of year. In January, the northern hemisphere is tilted away from the sun's direct light. Another way to say it is the sun appears to be higher in the sky in the summer than it does in the winter. This is a much more important factor than the (percentage-wise) small, temporary fluctuation in distance we are away from the sun.  --TS