Weekend travel outlook

After a quiet stretch of weather here in Chicago, a more active pattern will evolve this weekend that will last into the early part of next week.   For the very latest advisories, watches and warnings on what could be a significant snow maker for portions of the Midwest, check out the WGN Severe Weather Blog.

http://weblogs.wgntv.com/chicago-weather/severe-weather/

Or you can always google “WGN Severe Weather Blog”.

Weekend travel outlook

There are two systems we are watching closely that have the potential to affect weekend travel here in Chicago and across the Midwest.  

Tonight and Saturday: The first system is expected to bring two to six inches of snow to sections of Iowa, Nebraska and Missouri Friday night and Saturday.  A Winter Weather Advisory has been posted for these areas (see map below).   As this first storm approaches Illinois, it is expected to weaken considerably. Snowfall totals here in the Chicago area should be in the one inch range. With temperatures on Saturday close to the freezing mark, local travel should not be adversely affected.  So far this storm has dropped up to 4 inches of snow across sections of southwest Iowa.   

Sunday night and Monday:  A much more dynamic storm enters the Midwest and this storm has the potential to be a big snow maker (new computer model guidance suggests up to a foot of snow) for some areas.   As of Friday morning, it is too early to tell just who will end up in the heavy snow band, but the scenario will come into a clearer focus as we head into the first part of the weekend.

Check back with the WGN Severe Weather Blog throughout the weekend for updated information on these storms. 

 

Tim's Weather World: Hurricanes & Droughts

Changes have been made to the hurricane wind scale.  The original Saffir-Simpson scale was named after the men who developed it.  Herbert Saffir was a consulting engineer and Robert Simpson was the director of the National Hurricane center from 1967 through 1973.  The updated scale now takes into account the fact that storm surge values and the flooding attributed to them, depend on the size, intensity, and motion of each storm.  Meteorologists have found storm surge values don’t always stay within the ranges given in the original scale.  

In an article from NOAA, Hurricane Ike in 2008 and Hurricane Charley in 2004 are cited as good examples of this.  Ike was a very large Category 2 storm that struck the upper coast of Texas with a storm surge between 15 and 20 feet.  On the other hand, Charley was a Category 4 storm that hit Southwest Florida but only produced a 6 to 7 foot storm surge.  So the end result is that the National Weather Service has dropped the storm surge criteria from the Saffir-Simpson scale.  The scale will no longer couple the hurricane category with a specific storm surge.  However, storm surge forecasts will still be included in advisories issued by the National Hurricane Center and local weather service offices.

 

NOAAHurricane.jpgSpeaking of tropical weather…

It was a tropical storm that helped first break an extreme drought over the south.  Tropical storm Fay brought much needed rain to the region back in 2008.  That storm and other wet systems along with an El Nino weather pattern and other factors, has effectively ended a drought that affected nearly half the country at its peak.  Almost 50% of the country was experiencing drought conditions in 2007 but that number has dropped to just 7% today.  Climate scientists are calling it an extraordinary comeback.

Chance of major snow after Feb. 18

Dear Tom,
Chicago’s winter is drawing to a close, but I know plenty of snow is still possible. Can you provide some hard evidence? What is the likelihood of major storms? Despite the inconvenience, I enjoy big snows.
–William Wroblinski, Chicago

Dear William,
Your desire for “major storms” is far from hopeless. As of Friday, an average of 28.4 inches of snow (73 percent) of Chicago’s full-season snowfall of 39.0 inches has come down and 10.6 inches is yet to fall (Midway Airport data).
But weatherwise Chicagoans understand that averages rarely tell the real weather story. Our day-to-day weather often consists of wide swings above and below the climatological averages, and so it is with snowfall. Midway has logged 35 snowstorms of 10 inches or more accumulation since 1928, and 10 of them (28 percent) occurred after Feb. 18. And that includes a whopper: 22.3 inches on March 25-26,1930.