Do April showers bring May flowers?

Do April showers bring May flowers?
For most plants the first flowering is more
tied to the temperature than to rain.
(Photo credit: State Journal archives)

George Latimer Apperson’s “Dictionary of Proverbs,” traces the phrase “April showers bring May flowers” to the late 1880s and may even go back to the early 15th century.

Weather forecasts based on weather wisdom in folklore are based on careful observations of nature and the skies and correlating those observations with weather events. Some sayings are grounded in atmospheric physics and some seem a bit silly.

In general, rain would have a positive effect on the abundance of flowers provided too much didn’t lead to flooding. A geographic region with a rainy season would certainly start plants to flower after a good soaking of the soil.

A long-term drought would have a negative impact on plants and when they flower. However, for most plants the first flowering is more tied to the temperature than to rain. The development of plants depends on the accumulation of heat.

Recent research

There was a research study in 2013 that examined the first flowering time for 23 native species in Wisconsin based on flowering records initiated by Aldo Leopold in 1935. The scientists considered two time periods, 1935 to 1945 and 1977 to 2012. May 7 was the mean flowering date for the earlier period, while for the latter time period the mean flowering date was May 1.

This is consistent with the observations that the last frost has been occurring earlier in the year in Wisconsin. The change is not much for Dane County, but in northwestern Wisconsin, the last frost date now occurs about two weeks earlier than it did in 1950.

Should we change the saying to “Warm temperatures in March bring April flowers”?

It doesn’t have the same ring to it as the current, and thus is not likely to endure. The revised saying may also not be true as many plants need a dormant period of colder temperatures to thrive.

Category: Climate, Meteorology, Seasons

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How do I prepare for severe weather?

Lightning crackles over the Root River just west of downtown Racine as a storm front moves over the area. The National Weather Service advises: When thunder roars, go indoors. (Photo credit: Racine Journal Times Archives)

Severe summer weather can happen at any time and anywhere. The three biggest severe weather killers in the United States today are tornadoes, lightning and flash floods. Your best protection is to be prepared.

First, you need access to reliable weather information so you remain alert for potential weather hazards. Get a NOAA weather radio for weather updates. Subscribe to wireless emergency alerts, or WEAs, that provide free messages to your cell phone that will alert you about severe weather in your area. For more information on WEA Alerts, go to www.ready.gov/warning-systems-signals.

Tune in to local forecasters on radio or television to get additional information. Local forecasters are experts on regional weather and can interpret observations and conditions for you.

In the case of tornado, go into a tornado shelter or the basement or into a small interior room on the lowest floor of a building, such as a bathroom or closet. Protect yourself from flying debris and stay away from windows. If you are in a mobile home or car, leave it and go to a strong building.

As for lightning, the National Weather Service, or NWS, advocates the simple rule: “When thunder roars, go indoors!” Avoid flagpoles, metal fences, golf carts, baseball dugouts and farm equipment. If you are in a forest, seek shelter in a low area under a thick growth of bushes or small trees.

Move to high ground when threatened by flooding. Stay out of flooded areas. Never drive your car across a flooded road, even if you think the water is shallow. As the NWS says, “Turn around, don’t drown.”

The NWS provides information and ideas for preparing for severe weather and you can learn more safety tips, available at www.ready.gov/severe-weather.

Category: Severe Weather, Weather Dangers

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When does spring begin?

The 2018 vernal equinox occurs Tuesday March 20th at 11:15 a.m.

Civilizations throughout the long span of human history in our hemisphere have celebrated this day as it marks the beginning of a continuous six-month period during which the daytime is longer than the nighttime.

The consequences of this dramatic change are many. Of course, the weather begins to noticeably warm around this time of year, reaching an annual maximum approximately four months from now before slipping, at first slowly, back toward the coolness of fall.

Since the weather-producing jet stream is located on the warm edge of the cold air that caps the high latitudes of our hemisphere, this warming drives the jet stream poleward, resulting in a reduction in the frequency of large-scale cyclones across North America as we head into spring and summer.

As the sun continues to climb higher into the sky after the equinox, melting begins in the ice-choked Arctic and increases its pace throughout the summer before finally experiencing the first freezes of the next cold season in mid-September. So, though the occasional cold morning or dreary, raw day may yet remind us of the wisdom of the old saying, “The first day of spring is one thing, but the first spring day is quite another,” take heart in the fact that, as of March 20th, we have turned the page to an entirely different, more benevolent meteorological reality.

Steve Ackerman and Jonathan Martin, professors in the UW-Madison department of atmospheric and oceanic sciences, are guests on WHA radio (970 AM) at 11:45 a.m. the last Monday of each month.
Category: Seasons

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How severe was our just-completed meteorological winter?

Employing data from the last 70 winter seasons (December, January and February) we have been examining the extent of air colder than 23 degrees over the Northern Hemisphere. This year’s winter season was the 23rd warmest of the last 70. Not particularly impressive considering that just three years ago we had the very warmest winter season in seven decades.

Using the same data, we have recently been attempting to develop a reasonable measure of the duration of the winter over a region encompassing the Great Lakes.

We divided the 70-year data set into two 30-year periods, 1948/49 to 1977/78 and 1980/81 to 2009/10. We then determined, for each 30-year period, the calendar days on which there was, on average, a 90 percent chance that the coldest day of the year was still yet to come. For instance, no winter in all those years recorded its coldest day as early as Dec. 1. Thus, on that day, the chance that a colder day is still to come is 100 percent.

In the older data set, the 90 percent day is Dec. 16 while the 10 percent day is March 3. Thus, one could make an argument that, on average, our winter extended from Dec. 16 to March 3 in that earlier period.

In the more recent period, the 90 percent-10 percent interval extends from Dec. 30 to Feb. 18 — nearly four weeks shorter than the prior period. This preliminary result suggests that as the Earth continues to warm, not only is winter less extreme, but it may also be substantially shorter.

Steve Ackerman and Jonathan Martin, professors in the UW-Madison department of atmospheric and oceanic sciences, are guests on WHA radio (970 AM) at 11:45 a.m. the last Monday of each month.
Category: Uncategorized

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Does the U.S. have a new weather satellite?

March 1st GOES-S satellite launch from
Kennedy Space Center. Photo credit: M. Deep

Yes! The U.S. launched a new weather satellite on Thursday March 1st.

This is the second in a series of four next-generation weather satellites now in orbit 22,300 miles above the Earth. It will reach its final orbit location in approximately two weeks, and will be referred to as GOES-17 (Geostationary Operational Environmental Satellite, number 17).

It will orbit above the western part of North America and will provide faster, more accurate observations for tracking wildfires, fog and storm systems and hazards that threaten the western United States, including Hawaii and Alaska.

Satellite data help forecast the weather in two ways: Expert forecasters interpret the images, and numerical weather-prediction models assimilate observations. Image analysis plays an important role in short-term forecasts, those that predict the weather one to three hours into the future. Numerical weather predictions are more useful in 12-hour to three-day forecasts.

While weather forecasters routinely analyze current satellite observations, most data never reaches forecasters’ eyes. Most satellite observations go directly into numerical weather-prediction models. In fact, today’s weather forecast models rely on satellite data more than any other weather observation. These data include the vertical distribution of temperature and humidity, cloud distributions, land and sea surface temperatures, location of volcanic ash and wind speeds and directions.

Today, more than 120 U.S. space-based instruments observe our planet.

Other nations have just as much interest in observing weather from space as does the U.S. International collaborations organized through the World Meteorological Organization offer a powerful way to understand weather on a global scale.

Steve Ackerman and Jonathan Martin, professors in the UW-Madison department of atmospheric and oceanic sciences, are guests on WHA radio (970 AM) at 11:45 a.m. the last Monday of each month.
Category: Uncategorized

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