Outlook for Spring and Summer from NWS

The new outlooks for March, Spring, and Summer from the National Weather Service’s Climate Prediction Center are out.  You can click on any map to see the larger version.

Overview: The NWS says that La Nina conditions continued through January and into early February across the equatorial Pacific Ocean, as indicated by oceanic and atmospheric observations. The CPC/IRI consensus ENSO forecast indicates that La Nina conditions are expected to decay rapidly and transition to ENSO-neutral conditions during Spring. ENSO-neutral conditions are favored to persist through at least the summer.

March

Parts of Illinois shaded in blue have an increased chance of colder than normal conditions. This is part of a larger area of expected colder conditions that extend from the Midwest westward and is a classic La Nina signal for this region. Current climate conditions do not favor colder or warmer than normal conditions in the rest of Illinois. Current climate conditions do not favor wetter or drier than normal conditions in Illinois in March.

March-April-May

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NWS Outlook for First Half of 2018

The NWS released their new outlooks for the first half of 2018. First of all, the NWS notes that La Niña conditions continue across the Pacific Ocean and will likely persist through the rest of winter. It will likely fade this spring, leading to so-called “ENSO-neutral” conditions, which will continue through summer. “ENSO-neutral” just means that we are between La Niña and El Niño conditions, in other words, neutral.

January

The shorter-range forecasts out to 14 days indicate a shift in the weather pattern bringing warmer and wetter than normal conditions across Illinois. By this Sunday we could be in the 40s and 50s in Illinois (left panel, below) while the prospects of rainfall are high with potential totals of 1/2 to 1 inch over the next 7 days (right panel).

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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.

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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.

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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.

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Temperature

Precipitation

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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.

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More on the seasonal forecast

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