Do thunderstorms cause milk to spoil?

Posted on August 5, 2024 by WeatherGuys Editor

No, but it was once widely thought that summertime thunderstorms could cause fresh milk to curdle.

This thinking was based on observations that raw milk would spoil during lightning and thunderstorms. But it was neither the thunderstorms nor lightning that caused the spoiling; rather it was the atmospheric conditions. The conditions that are optimum for thunderstorm development are the same as those that would cause milk to spoil.

Milk curdles because of bacteria, not because of thunderstorms. Microbes in milk consume the milk’s natural sugars and produce lactic acid as a waste product. This coagulates the milk’s proteins, resulting in lumps in the milk and making the milk taste sour. Bacteria thrive in warm, humid conditions, so hot and humid days were particularly troublesome to early dairy farmers. These same atmospheric conditions are also favorable for summertime thunderstorms.

Thunderstorms require warm moist air that rises, so the environmental conditions that support thunderstorm development are like those in which milk can spoil. This similarity led to the observed correlation of milk spoiling during thunderstorms. But the conclusion that the thunderstorm caused the milk to spoil was incorrect.

An article in the journal Science in 1891 by A.L. Treadwell may be the first to suggest that milk spoils because of bacteria. In 1927, E.H. Farrington published an article that summarized his experiments and noted that “sultry atmosphere usually precedes thunder showers and provides favorable conditions for the growth of milk-souring bacteria.” Part of his career included a professorship at the University of Wisconsin, where the paper was published. “Sultry” is typically used to describe summer stretches of warm days and nights with high dew points.

Pasteurization and refrigeration prevent the milk from spoiling, as they make environments that are too hot or cold for bacteria to thrive. We have not developed the technologies to prevent thunderstorms from developing.

Steve Ackerman and Jonathan Martin, professors in the UW-Madison department of atmospheric and oceanic sciences, are guests on WHA radio (970 AM) at noon the last Monday of each month. send them your questions at stevea@ssec.wisc.edu or jemarti1@wisc.edu.

Category: Meteorology, Severe Weather

Comments Off on Do thunderstorms cause milk to spoil?

Are thunderstorm rain amounts hard to predict?

Posted on July 29, 2024 by WeatherGuys Editor

Meteorologists would generally agree that summer is the most challenging time of year for making accurate rain forecasts.

Neither scattered nor isolated stroms give any indication of whether the storm is severe or when it’s happening. These two terms only refer to how much of an area it is expected to cover. (Image credit: Weather Station Advisor)

During summer, there generally is enough moisture and atmospheric instability to help fuel the development of rain showers. Scattered thunderstorms are one of the most difficult weather events to forecast.

Thunderstorm development also is difficult to pinpoint in the summer. Summer thunderstorms sometimes develop from subtle outflow boundaries from previous thunderstorms, sea-breeze fronts, higher terrain or localized solar heating.

Numerical weather prediction models help define areas where conditions will be right for the development of thunderstorms.

These models are designed to calculate atmospheric conditions over a large area but cannot pinpoint the locations of a particular thunderstorm development. Summer thunderstorm forecasts are often broad, using terms like “isolated” and “scattered.”

“Isolated” corresponds with a 10% chance of measurable precipitation (0.01 inches or greater). “Scattered” indicates that there will be 30% to 50% coverage of convective weather, such as thunderstorms, in the forecast zone. “Widely scattered” is used for a forecast of 20% coverage. If you are planning outdoor activities and the chances of rain are 10% to 20%, it is a good idea to have backup plans for moving indoors.

Along with numerical models, satellites and ground based radars contribute a significant amount of additional information for forecasters as the storms develop. It is wise to have a weather radar app on your smartphone to see whether any thunderstorms are nearby.

The National Weather Service issues a severe thunderstorm warning when a thunderstorm is producing wind gusts of at least 58 miles per hour or hail of at least 1 inch in diameter.

If a tornado is detected, a tornado warning will be issued either in replacement of or concurrently with the existing severe thunderstorm warning. Severe thunderstorm warnings should not be ignored, as severe thunderstorms are dangerous and occasionally deadly.

Steve Ackerman and Jonathan Martin, professors in the UW-Madison Department of Atmospheric and Oceanic Sciences, are guests on WHA radio (970 AM) at noon the last Monday of each month. Send them your questions at stevea@ssec.wisc.edu or jemarti1@wisc.edu.

Category: Meteorology, Severe Weather

Comments Off on Are thunderstorm rain amounts hard to predict?

How does our late spring/early summer precipitation stack up historically?

Posted on July 22, 2024 by WeatherGuys Editor

If you think the first half of the summer has been unusually wet, it is not merely your impression — it is a measured fact.

Between May 1 and July 15, Madison received 21.85 inches of precipitation, punctuated by the 18th-wettest day in Madison history (3.3 inches on July 14) — which is 10.16 inches above normal.

In other words, since May 1 we have received nearly twice the normal rainfall in the wettest part of the year. In fact, this amount is the all-time record for May 1 to July 15 in Madison and one of only two such periods (the other was in 2000) during which 20 inches of rain or more has fallen. Perhaps unsurprisingly, in the 76 days of this interval, we have had only 30 completely dry days — well less than half. Consistent with this incredible total, only one time in this period have we had as many as five consecutive days during which not even a trace of precipitation fell — May 14-18.

Yet another interesting fact regarding this remarkable wet period is that over the same interval the daily average temperature has been 2.54 degrees Fahrenheit above normal. Historically, rainy late spring/early summers have been closer to average or even a bit cooler than normal as a result of the persistent cloud cover that usually accompanies such prolonged rainy periods. The four other rainiest May 1 through July 15 periods, for instance, averaged 0.55 degrees below average (2000), 0.44 degrees above average (2013), 1.76 degrees below average (2008) and 0.30 degrees below average (1993) — nothing at all like this year.

Since warmer air has a greater capacity for water vapor which is then available for conversion into precipitation, the combination of unusual precipitation amounts and higher than average temperatures is clearly suggestive of global warming.

Steve Ackerman and Jonathan Martin, professors in the UW-Madison department of atmospheric and oceanic sciences, are guests on WHA radio (970 AM) at noon the last Monday of each month. send them your questions at stevea@ssec.wisc.edu or jemarti1@wisc.edu.

Category: History, Seasons

Comments Off on How does our late spring/early summer precipitation stack up historically?

What happens to the wintertime cold pool in summertime?

Posted on July 16, 2024 by WeatherGuys Editor

We have commented a number of times in the past few years about the areal extent of the hemispheric cold pool of air at 850 millibars (about a mile above the surface) during the winter. As one might expect, that pool expands dramatically from October through February and then begins to contract as we move toward spring and summer.

People cool off in misters along the las Vegas strip last week. the northern Hemisphere’s cold pool of air about a mile above the earth, which extends 27 million square miles in winter, often disappears entirely during the summer. (Photo credit: John Locher, Associated Press)

Our analysis uses the minus 5 Celsius isotherm (line of constant temperature) and has shown that the average winter cold pool area has systematically shrunk for at least the past 76 years. One might reasonably wonder if this cold pool survives at all during the height of Northern Hemisphere summer. As it turns out, some summers have a number of days in mid-July on which there is absolutely no air at 850 mb that is as cold as minus 5 Celsius. Roughly half of the last 76 years have had such a “vanishing” cold pool, with the pool getting very close to vanishing many of the other years.

The calendar date on which the smallest areal extent is observed in a given summer varies from around July 4 to as late as July 23. Thus, later this week we will likely be close to the day of the minimum area for the year.

With no intention to distract from the pleasant summer we are all currently enjoying, reaching the annual minimum this week means that by the beginning of next week the cold pool will begin its slow, inevitable expansion again — culminating in the coldest week of the year in late January when the cold pool will cover nearly 27 million square miles.

Enjoy the summer — it can’t last!

Steve Ackerman and Jonathan Martin, professors in the UW-Madison department of atmospheric and oceanic sciences, are guests on WHA radio (970 AM) at noon the last Monday of each month. send them your questions at stevea@ssec.wisc.edu or jemarti1@wisc.edu.

Category: Climate, Seasons

Comments Off on What happens to the wintertime cold pool in summertime?

Was Hurricane Beryl a special storm?

Posted on July 8, 2024 by WeatherGuys Editor

All hurricanes are special, given the extensive damage they can cause when they make landfall. Beryl was considered extra special because it was a record-breaking storm.

Hurricane Beryl gained 95 mph in less than two days, a process known as rapid intensification. (Image credit: NOAA)

Beryl rapidly intensified from a tropical storm to a major hurricane (Category 3 or higher) with wind speeds that increased to 95 mph in less than two days. Category 3 storms have sustained winds between 111 mph and 129 mph. Only six other Atlantic Basin storms have intensified this quickly and those storms all happened after August, the typical time of year with conditions favorable for hurricanes.

Beryl is the earliest Category 4 or 5 hurricane on record. It set the record for the earliest Category 4 (sustained winds of 130 mph to 156 mph) by more than a week, breaking the record set by Hurricane Dennis on July 8, 2005. It is the easternmost major hurricane to form in the month of June. Beryl is the only Category 4 hurricane in the Atlantic Basin to occur in June and only the third Category 3 Atlantic Basin hurricane to occur in June.

Beryl also broke the record for the earliest Category 5 hurricane by more than two weeks. Category 5 hurricanes have sustained winds of 157 mph or higher. Hurricane Beryl was deemed Category 5 on July 1, breaking the record set by Hurricane Emily on July 17, 2005. Beryl is the strongest July Atlantic hurricane ever measured.

Forecasters expect the 2024 hurricane season to be one of the busiest seasons on record. This is due to the ocean water temperatures being so warm at this time of year. Warmer waters support stronger hurricanes. A La Niña pattern is predicted to develop later in the season, which makes the atmosphere more supportive for hurricanes and could also steer more storms toward the U.S.

Steve Ackerman and Jonathan Martin, professors in the UW-Madison department of atmospheric and oceanic sciences, are guests on WHA radio (970 AM) at noon the last Monday of each month. Send them your questions at stevea@ssec.wisc.edu or jemarti1@wisc.edu.

Category: History, Tropical

Comments Off on Was Hurricane Beryl a special storm?