El Nino and the Latest NWS Outlook for Summer, Fall, and Winter

Summary: According to the NWS Climate Prediction Center, El Niño has arrived and has a 90% chance of staying this summer and an 80% chance of remaining through the end of 2015. In terms of strength, this El Niño is expected to be weak to moderate. Illinois is expected to have an increased chance of cooler-than-average conditions in the late summer and on into fall.

The El Niño event has arrived (finally) and heavily influenced the NWS climate outlooks released this morning. For June (first map below), the Southern Plains are expected to have an increased chance of cooler-than-average temperatures. A large part of the US is expected to have an increased chance of wetter-than-average precipitation, including the southern two-thirds of Illinois.

For the period June-August (second row of maps), the increased chance for cooler-than-average conditions stretches northward and eastward and includes far western Illinois. The  increased chance for wetter-than-average conditions does not cover Illinois. This should not be a concern since no part of Illinois is in drought right now.

Later forecasts for July-September, August-October, and September-November show in increased chance of cooler-than-average across Illinois (see second, larger map below for the July-September temperatures). Continue reading

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Rivers Have No Effect on Tornado Tracks

The Kansas City NWS office posted this image showing that rivers have no measurable effect on tornado tracks.

tornadoes-vs-rivers

Click to enlarge.

The case for St. Louis reminded me that one of the worst tornado disasters in US history occurred when a tornado tracked through St. Louis, jumped the Mississippi River, and continued doing damage in East St. Louis. That was May 27, 1896. Besides busting the myth about rivers, it busted the myth that tornadoes do not hit major cities. At the time, St. Louis had a population close to 500,000.

The St. Louis Public Library has a great collection of photos and newspaper articles on the event. A total of 255 people were killed in both Illinois and Missouri. It was estimated to be an F-4 tornado on the Fujita scale, based on the damage seen in photographs.

Nine days after the event, a book was published based on newspaper accounts with lots of photos. It has recently been reprinted by Southern Illinois University Press and called “The Great Cyclone at St Louis and East St Louis, May 27, 1896″. Besides the incredible amount of detail on the storm’s damage, you are treated to some vivid and lurid prose (which was the newspaper style of the day).

Example of the damage from the 1896 event.

"St Louis Jefferson-Allen Damage" by http://www.photolib.noaa.gov/historic/nws/wea00256.htm "Photo by Strauss". Licensed under Public Domain via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:St_Louis_Jefferson-Allen_Damage.jpg#/media/File:St_Louis_Jefferson-Allen_Damage.jpg

Click to enlarge. “St Louis Jefferson-Allen Damage” by http://www.photolib.noaa.gov/historic/nws/wea00256.htm “Photo by Strauss”. Licensed under Public Domain via Wikimedia Commons – http://commons.wikimedia.org/wiki/File:St_Louis_Jefferson-Allen_Damage.jpg#/media/File:St_Louis_Jefferson-Allen_Damage.jpg

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New Climate Extremes Tool

Someone just pointed out this interesting climate extremes tool from the Southern Regional Climate Center. Here is the URL: http://extremes.srcc.lsu.edu/

From there you can choose the product, which is the type of all-time record – for the month, for the day, or for the year. Then you select your variable: record high, record low, etc. And finally the month of interest.  So far it only does temperatures and is limited to airport data.

Here is a screen shot of the all-time record highs for April in the Midwest. In the tool, instead of this screen shot, when you mouse over one of the records it gives you more details on the record and dates. It is an interesting tool – I just wish it included the longer NWS Cooperative Observer records.

EXTREMES

Source: Southern Regional Climate Center. Click to enlarge.

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7-Day Rainfall for Illinois

Here is the NWS radar/rain gauge product that takes advantage of good spatial coverage of radar with the accuracy of rain gauges for the last 7 days. The oranges, pink, and red, indicate amounts of 2 to 5 inches and covers much of the state. The heaviest amounts of 4 inches or more were east of St. Louis. Meanwhile the lightest amounts were in northwest Illinois were in the range of 0.25 to 0.5 inches.  Continue reading

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Monthly Temperature and Precipitation for 2015 in Illinois

How things are shaping up in 2015? The outstanding features so far are the extremely cold February and the extremely wet conditions in southern Illinois while dry elsewhere.

Monthly Temperature Departures from Average

Blue means colder than average, red means warmer than average. Temperature departures from average tend to cover very large areas, making the statewide average temperature departure a good indicator of conditions around Illinois.

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Monthly Precipitation Departures from Average

Continue reading

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Wet Weather Ahead for Illinois

Here is the Qualitative Precipitation Forecast (QPF) for the next 7 days, according to the National Weather Service. This shows the potential amounts of rainfall, your mileage may vary. The area in shades of violet and purple are 1.5 to 2.5 inches. Shades of blue are 1 to 1.5 inches. Most of this is expected to fall in the next 3 days.

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Here is how much rain has fallen so far in May across the Midwest.

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April Temperatures in Illinois Warm Over the Last Century

According to the National Centers for Environmental Information (NCEI), the average April temperature in Illinois has warmed by 2 degrees over the last century. In addition, the most recent decade of 2006-2015 was the warmest set of Aprils on record. Statewide records go back to 1895.

Here are the statewide average temperatures for April in Illinois plotted by year. The purple line and black dots show the year-to-year variability in April temperatures in Illinois. The blue line shows the upward trend. You can find the original data and graph here.

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