Outlook for Summer, Above Normal Temps

The NWS released their outlooks for the month of July and the 3-month period of July-September.

Illinois and much of the US has an increased chance of warmer-than-normal temperatures for both July and July-September (first column in the figure). Illinois has equal chances of being above, below, and near-normal on rainfall – a virtual coin toss. That is not a surprise on the rainfall. Most of our summertime rain is guided by local conditions and fast-changing weather patterns.

page2

Historical Trends for July

Temperatures: Historically in Illinois, daytime temperatures in July have become milder over time (first graph) while nighttime temperatures have become warmer over time (second graph). While the decreased heating during the day may be welcome, the increased warming at night can be problematic for humans, animals, and plants as they rest. The green line is a smoothed curve to help the eye see the underlying pattern of change from the variability of individual years. Continue reading

Above-Average Temperatures Expected to Continue through Fall

The NWS released their latest forecasts for May and beyond. Currently, the Pacific Ocean is in the neutral phase between La Niña and El Niño. There is much debate on if and when El Niño should return. It could happen in late summer.  Meanwhile, the theme running through the outlooks is the increased risk of above-average temperatures through the fall. Illinois has been running warmer than average in the last few years. In 2016, 10 out of 12 months were above-average. So far, every month in 2017 has been above-average.

  • January 2017: 5.7 degrees above average
  • February 2017: 10.1 degrees above average
  • March 2017: 1.9 degrees above average
  • April 1-19, 2017: 6.5 degrees above average

May: eastern portions of Illinois have a slightly increased chance of being warmer than average. I am going out a little farther on the limb and say that all of Illinois has an increased chance of being warmer than average, based on recent trends and the climate models. Meanwhile, most of Illinois and the Great Lakes are expected to have an increased chance of below-average precipitation. Click to enlarge maps. Continue reading

Outlook for March, Spring, and Summer

The National Weather Service just released their outlook for March and spring. We have moved out of the La Niña pattern in the Pacific pattern to something called ENSO-neutral conditions this spring.That means we are between the El Niño and La Niña phases in the Pacific Ocean. Some of the predictive models are indicating a shift towards a weak El Niño by summer. That is actually good news for Illinois since we have a tendency to experience milder summer temperatures under those situations.

For March, they have Illinois in a region called “EC”, meaning that we have equal chances of being above, below, or near-normal on temperature and precipitation. Sometimes I call “EC” a neutral forecast because it does not lean one way or another.

For March-May, Illinois has an increased chance of above-normal temperatures and northern Illinois has an increased chance of above-normal precipitation.

page2

Continue reading

November Trending Warmer, Wetter

Based on historical data for Illinois, the weather in November is trending towards warmer and wetter conditions over time. Based on the latest NWS forecasts, this November is likely to continue that pattern.

Historical Trends

Temperature

The statewide average temperature for November shows a wide variation from year to year – typical of all months in Illinois. However, there is an underlying warming trend of about 2 degrees over the last century.

nov-temp
Temperature

Precipitation

Continue reading

Latest Seasonal Forecasts for Illinois – A Mild Winter?

The NWS Climate Prediction Center released their latest seasonal forecasts today. Here are the results for Illinois. The biggest news is that Illinois has an increased chance of above-average temperatures and below-average precipitation for the winter months of December, January, and February. This forecast is based largely on the developing El Niño in the Pacific Ocean.

While the forecast of a milder winter may sound appealing, I would not leave the winter coat in the closet and throw away the snow shovel just yet. Two things to consider are: 1) this is not a 100% guarantee, other factors come into play in determining our winter weather, and 2) even a mild winter can contain short periods of intense cold and abundant snowfall.

Slide33

More on the seasonal forecast

Continue reading

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 finally arrived and heavily influenced the NWS climate outlooks released this morning. For June (first figure, top row), 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 (first figure, second row), 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 now.

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

NWS Outlook for the Growing Season in Illinois

The NOAA Climate Prediction Center has released their monthly and seasonal outlooks for the growing season.

In the near-future, the 6-10 and 8-14 day forecast indicate that colder-than-average conditions will prevail for the next two weeks. For precipitation, there is an increased chance of drier-than-average conditions in parts of northern Illinois for the next two weeks.

There is not a lot to report for Illinois at the medium range. We are in equal chances (EC) for above-, below-, and near-average temperature and precipitation for both May and the 3-month period of May-July.

page2

Continue reading