Stories tagged weather

Feb
01
2016

Long before computers, the Weather Channel and the internet, humans needed weather forecasts. Farmers and sailors particularly needed to know if storms were approaching. Over time, various folklore forecasts, often in the form of short rhymes, were devised and passed down through the generations. Although memorable, the folklore forecasts are of uneven quality—some good, others bad.

Groundhog Day is an example of predicting the weather based on folklore. If the groundhog comes out of its hole and sees its shadow, we are in store for forty more days of winter. Of course, after February 2, there are only 47 days left of astronomical winter – which ends on or about March 21!

The roots of Groundhog Day go back to the 6th century. February 2 is forty days after Christmas and is known as Candlemas. On this day, candles that are used for the rest of the year are blessed. This is also about the mid-point in winter, in meteorological not astronomical terms. The forecast rhyme goes:

"If Candlemas Day is bright and clear
There’ll be two winters in that year;
But if Candlemas Day is mild or brings rain,
Winter is gone and will not come again."

If the day is bright and clear, the groundhog “sees” his shadow and we have more winter. Of course, the weather conditions on February 2 at single locations like Punxsutawney, PA or Sun Prairie, WI tells us nothing about the weather for the rest of the winter season. As for accuracy - the “predictions” made by the various rodents involved in this annual event are correct about 40% of the time – vastly inferior to what is delivered by modern science. Right or wrong, they are fun community celebrations.

Every summer, we get to see incredible photos of massive mayfly hatchings somewhere along the Mississippi River. This year, however, a huge sudden hatching was captured on the National Weather Service radar based in LaCrosse, Wisc. Click through the link to see this incredible phenomenon.

Jan
07
2014

Dude, what's the wind chill?: The first wind chill calculations were made in Antarctica, but not by penguins.
Dude, what's the wind chill?: The first wind chill calculations were made in Antarctica, but not by penguins.Courtesy Frank Hurley
As we're nearing the end of this polar vortex-driven, bone-chilling weather, it's a good time to review exactly what is wind chill and how the wind chill index is calculated.

Q: What is wind chill?
A:
It's the term used to describe the rate of heat loss on the human body resulting from the combined effect of low temperature and wind. As winds increase, heat is carried away from the body at a faster rate, driving down both the skin temperature and eventually the internal body temperature. Wind does not change the temperature of the air. If a thermometer is placed outside, it will read the same temperature regardless of whether it's a windy day or a calm day. It simply "feels" colder because the heat that we give off is immediately blown away.

Q: Has this always been calculated the same way?
A:
No. And it's good to keep that in mind as we've gone through some record-breaking cold temps. Old records for wind chills might not be the records we once thought they were.

Q: Why is that?
A:
In 2001, the National Weather Service implemented a new wind chill Temperature Index. The new index will usually be warmer than what you would have expected with the old index. The new wind chill temperature Index uses updated science and technology and new forms of computer modeling to provide a more accurate indication of the impact of wind on how it feels outside.

Q: Can I figure conversions between the new and old wind chill formulas?
A:
Yes you can. Click here to get to an online wind chill calculator. You'll need to know the air temperature and wind speed of the place you want to figure the wind chill for. This web link also has
charts that show the differences between the old and new calculations.

Q: How can I protect myself when there are high wind chills?
A:
Here are some good tips courtesy of the Weather Chennal
• Wear layers of loose-fitting, lightweight, warm clothing. Trapped air between the layers will insulate you. Outer garments should be tightly woven, water repellent, and hooded.
• Wear a hat, because 40 percent of your body heat can be lost from your head.
• Cover your mouth to protect your lungs from extreme cold.
• Mittens, snug at the wrist, are better than gloves.
• Try to stay dry and out of the wind.

Yes, it's really cold in Minnesota today. As I write this mid Monday afternoon, the outside temp is -14 degrees. Schools are closed, many people are working from home, there is great despair in general. Unless you are an ash tree. This cold snap might just wipe out a great share of the Emerald Ash Borer larvae. Of course, it's not good news if you're Emerald Ash Borer larvae.

Well, it seems someplace has beat Minnesota's Record of -60 degrees Fahrenheit set on February 2nd, 1996. Admittedly that place is Antarctica. Tuesday this week it was announced that a satellite detected a temperature of -135.8 degrees Fahrenheit on the continent of Antarctica. Just to give you an idea of how cold that is, Dry Ice is -109.3 degrees Fahrenheit. That means that Dry Ice might naturally form at the SOUTH POLE!

Do you like hot weather? Do you like playing with graphs? Combine those two interests in at this interactive website that charts the fluxuation in global temperature over your own personal lifetime.

May
21
2013

More details are starting to emerge from the enormous tornado to rip through Oklahoma yesterday. Wind speeds were measured over 200 miles per hour. As of Tuesday morning, authorities had put the death toll at 24 but rescue crews were continuing to sort through the rubble looking for more casualties.

Here are a couple YouTube posts from storm chasers who were on the scene for yesterday's devastating tornado in Moore, Oklahoma. Listening to their voices, you can really get a feel for the huge magnitude of this tornado.

Oklahoma tornado paths: Three tornadoes have taken vary similar courses near Oklahoma City in the past 15 years.
Oklahoma tornado paths: Three tornadoes have taken vary similar courses near Oklahoma City in the past 15 years.Courtesy Oklahomanick
This map shows that three major tornadoes have taken very similar paths through this section of Oklahoma in the past 15 years, all occurring in May. The May 3, 1999 tornado killed 36 people and was rated EF-5, the strongest ranking on the tornado scale. The May 8, 2003 tornado was rated EF-4, but no one was killed. It is almost a certainty that the 2013 tornado will also be rated EF-5.

Click here to access an interactive slider graphic showing before and after aerial views of the destroyed Plaza Towers Elementary School building.

Satellite view: This satellite image shows the storm system that spawned the deadly tornado.
Satellite view: This satellite image shows the storm system that spawned the deadly tornado.Courtesy NOAA
NOAA (National Oceanic and Atmospheric Administration) captured this image of the storm system that spawned the tornado that hit Moore, Oklahoma. The storms’ violent updrafts sucked in air that shot up 40,000-50,000 feet or more into the atmosphere. The bubbly white structures you see in the image are known as overshooting cloud tops and are textbook features of violent thunderstorms.

A couple months ago, USA Today reported on global climate change's impact on tornadoes. You can read it here. Trying to draw conclusions about the impacts to this type of weather is twisted, to say the least.

Weather.com's Greg Forbes surveys the damage and gives his insights on the strength of the Oklahoma tornado.

Minnesota-based meteorologist Paul Douglas today gives some great analysis, and some amazing radar images, in the Start Tribune today on why this storm turned out to be so big and powerful. He also reviews the good and the better weather apps to have on your phone or mobile device to help you know when bad weather is coming.

Storm shelter: This commercially made storm shelter made of steel can hold up to six people.
Storm shelter: This commercially made storm shelter made of steel can hold up to six people.Courtesy Survive-a-storm
National Geographic shares information about how uncommon it is for tornadoes to hit developed, populated areas along with some of the basic science on what makes tornadoes occur.

USA Today reports that the phone is ringing off the hook for this tornado shelter sales company. A 4-by-6 steel shelter that can hold up to six people runs about $4,000. The demand is highest in the southern states where most homes are built without basements.

And here's the link to MDR's earlier post on the tornado, showing its movement in time lapse photography.

I tried posting a similar clip to this a couple weeks ago and the YouTube clip was pulled down. Now this weird combination of wind, long-lasting lake ice and warming temperatures are causing these ice spikes to surge out of lakes.

Apr
22
2013

People from all walks of life are fascinated by weather and make routine measurements. The “Cooperative Network” operated by the National Weather Service (or NWS) is a network of several thousand volunteers from across the country that routinely make and report weather observations. This Coop has operated continuously since 1890. The group includes about 9,000 weather observes who systematically measure high and low temperatures, rainfall and snow accumulation every day. These observations are archived at the National Climatic Data Center and are a large part of the historical weather record of the country.

Another group, the Community Collaborative Rain, Hail and Snow networks, or CoCoRaHS, includes 15,000 volunteers who help measure and report precipitation type and amounts every day. Observations of precipitation by a large group of volunteers are critical to understanding storms as precipitation varies widely from place to place even in a single storm. Such observations are useful for assessing flooding hazards and rapid snow melting. You can join CoCoRaHS at http://www.cocorahs.org.

There are also tens of thousands of citizens that serve as NWS severe weather spotters. The NWS relies on these storm spotters, along with radars, satellites and other data to supply observations that help in NWS’ decision making process of issuing and verifying severe weather warnings. The NWS is always looking for volunteers to help get the word out about severe storms. You can find out more about this group and sign up for classes and become a trained spotter at http://www.crh.noaa.gov/mkx/?n=spotters. It is a good class to take as we approach severe weather season.

So, if you enjoy making weather observations, join one of these groups and be one of the nation's weather observers!