wind

Tuesday weather: Sunny and 51, but rain expected later

Forecasters expect Tuesday to be sunny throughout the mid-valley, with highs around 51. But rain is expected later Tuesday night and Wednesday, with lows Tuesday in the mid-30s and highs Wednesday in the mid-40s.

Monday weather: Morning fog, then sun and highs around 47

Forecasters expect mostly sunny skies throughout the mid-valley on Monday, at least after patches of morning freezing fog burn off. Highs Monday will be around 47. Freezing fog is expected Monday night, as temperatures dip to the lower 20s. More sunshine and highs around 51 are expected on Tuesday.

Monday weather: Patchy morning fog, then sunny

Here’s a pattern to get used to for this week’s weather: Forecasters say to expect patchy fog in the morning, but when that clears, we’ll be seeing sunny skies. Monday’s forecast follows that formula; Patchy fog, then sun, with highs in the mid-50s. Monday night will be mostly cloudy, with lows around 40.

“The Answer My Friend Is Blowin’ In The Wind.”

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That is the title of one of Bob Dylan’s most famous songs and the wind is my topic this week. Dylan wrote the song in 1962 and it was released in 1963. The song became a protest theme for the anti Vietnam War protests and other protests that followed. Just in case you don’t remember the song his Bob Dylan singing it as recorded on Youtube.

Now to center more on the topic of wind. Here in the Pacific Northwest we can see some very strong winds as storms move inland from over the Pacific Ocean. According to The National Center for Atmospheric Research (NCAR) and the University Corporation for Atmospheric Research (UCAR) wind is defined as “moving air and is caused by differences in air pressure within our atmosphere. Air under high pressure moves toward areas of low pressure. The greater the difference in pressure, the faster the air flows.”

Wind Flow High To Low Pressure | Image by NOAA
Wind Flow High To Low Pressure | Image by NOAA

That explains how our wind storms develop as a strong surface low pressure center along with a warm front and a cold front race toward the Pacific coast. Strong high pressure is at the surface and aloft either over the Gulf of Alaska or the Pacific Ocean and a strong upper level low is usually along the coast or actually over the Pacific Northwest. The wind moves from the high pressure and rockets toward the low pressure centers. (See right side of the above graphic where surface storm approaches the Pacific coast) These storms have produced winds upward of 100 mph, particularly at the coast.

Tree Blown Down In Corvallis | The Corvallis Gazette-Times Amanda Cowan -kval.com
Tree Blown Down In Corvallis December 2014| The Corvallis Gazette-Times Amanda Cowan -kval.com

We’ve seen how dangerous strong winds can be, but we also know the wind can be a useful tool for propelling boats on the water, clearing out smoke and other pollutants from the air, and even producing energy.

NSSL
National Severe Storms Laboratory (NSSL) | Image cimms.ou.edu

The National Severe Storms Laboratory (NSSL) in Norman, Oklahoma has been a center for wind research. NSSL scientists have defined the types of damaging wind events that can occur. Quoting their web research page: “We are working on simulations of derecho events, long-lived windstorms that are associated with bands of rapidly moving showers or thunderstorms. Derechos can produce widespread straight-line winds up to 100 mph over long periods of time. Our simulations allow us to dissect the storms that produce derechos to better understand how to forecast and warn for them.”

How A Downburst Forms | Image by scijinks.jp..nasa.gov
How A Downburst Forms | Image by scijinks.jp..nasa.gov

We need to define a couple of terms now. A downburst is a strong downdraft which induces an outburst of damaging winds on or near the ground. A microburst is a small but powerful downburst. The scientists have been working to determine which storm will produce a microburst because they can form rapidly and cause serious problems for aircraft. The NSSL’s Dual- Polarized Mobile Radar is an important tool used to collect data on microbursts and dust storms. They compare their data with data collected by the Phoenix National Weather Service (NWS) dual-polarized Doppler Radar. There is also a special test field set up for research. They use the National Radar Testbed Phased Array Radar to follow the development, growth and evolution of damaging wind mechanisms when thunderstorms are within the range of their radar.

Bow Echo
Bow Echo & Derecho | Image by slideplayer.com

Here are some of the research projects organized to study damaging winds. The Bow Echo and Mesoscale Convective Vortices (MCV) experiment (BAMEX) was set up to gather data to better understand bow echoes and the high-damaging winds that are created. They used aircraft and mobile ground-based equipment to map the structure of thunderstorm complexes and mature mesoscale convective vortices. A bow echo is a curved shape shown on radar that indicates the possibility of severe weather and the possible formation of a tornado.

Mesovorticies
Mesovortices | Image by wunderground.com

Quoting the NSSL “An NSSL scientist studied low-altitude “mesovortices,” (atmospheric spin on the scale of a few km to several hundred km) and learned that they may be one of the causes of damaging straight-line winds. These results helped motivate the objectives for the BAMEX program defined above.”

DDPDA
DDDPA | Image by allacronyms.com

The final wind project listed was developed to help weather forecasters. The Damaging Downburst Prediction and Detection Algorithm (DDPDA), developed at the NSSL, uses radar-detectable features to predict the genesis of damaging downburst winds from high-reflectivity storm cells that develop in an environment of weak vertical shear. An Algorithm, as defined by Wikipedia, ” is a self-contained step-by-step set of operations to be performed. Algorithms exist that perform calculation, data processing and automated reasoning.” In short it is a computer program made for a specific task.

So the next time we have a windstorm remember that there are scientists at the NSSL and all over the world studying wind and its effects so that we might be better able to protect ourselves from its potential devastation.

Oh, just an aside. I wrote the title of this article before I found out that Bob Dylan is coming to the Cuthbert Amphitheater June 7th. It’s just a lucky coincidence I guess.

If you have an idea for a future topic let me know what you would like me to talk about or explain. You can comment below or email me at: [email protected].

Storm Uproots, Topples Tree

EUGENE, Ore. — Utility crews were on standby Monday night in preparation for potential outages and downed trees from a high wind advisory in the Willamette Valley.

The storm was already showing its strength at a home in the 2500 block of McMillan Street in South Eugene.

Strong winds uprooted and toppled a tree in a homeowner’s yard.

He says he heard a creaking noise, thought it was just a branch, looked outside and realized it was the entire tree.

It’s a sight not uncommon for some Southeast Eugene residents.

KEZI 9 News Reporter Sarah Hurwitz spoke with a man who’s tree came down in the last wind storm and the Eugene Water and Electric Board on their preparations for the storm.

Wind Damages Power Lines

10-26 stormMEDFORD, Ore. — Wind knocked out power for tens of thousands of people in Oregon and Northern California.

Fire crews and Pacific Power teams had to deal with downed trees crushing power lines and damaging property. Representatives with Pacific Power say they had every single crew available working to restore power throughout the day.

The Rogue Valley was mostly spared from power outages, but 25,000 homes lost power throughout Northern California and all of Oregon. Meanwhile the Douglas County Sheriff’s Office actually lost their 9-1-1 lines in the northern parts of the county.

Pacific Power says their crews are still on call if further need arises.

Kites Need It And So Do Sail boats.

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What I am talking about is wind. The National Weather Service defines wind as “the horizontal motion of air past a given point. Pressure that’s higher at one place than another sets up a force pushing from the high toward the low pressure. The greater the difference in pressures, the stronger the force. The distance between the area of high pressure and the area of low pressure also determines how fast the moving air is accelerated.”

Pressure Gradient Force | Image by myweb,cwpost.liu.edu
Pressure Gradient Force | Image by myweb,cwpost.liu.edu

That force is called the “pressure gradient force.” There are no set numbers for what constitutes high or low pressure. They are relative to each other. The pressure falls in one area and rises in another area and the wind flows from the high to the low. When wind speed and direction are reported the direction listed is where the wind is coming from, such as SW 10-15 mph, meaning the wind is moving from the southwest heading to the  northeast at 10 to 15 miles per hour. Wind speeds are reported in miles per hour or in knots per hour (particularly on the water or in the air). To convert knots per hour to miles per hour multiply the knots by 1.15.

Cup Anemometer On Right, Weathervane On Left | Photo by www.stormdebris.net
Cup Anemometer On Right, Weathervane On Left | Photo by www.stormdebris.net

The device used to measure the wind speed is called an “anemometer” which in its standard form is small cups aimed in the same direction on a rotating pole. As the cups catch the wind, the pole to which they are attached spins, at the speed of the wind which can be measured. The wind direction is shown by a “weathervane.”

Beaufort Scale For Wind Speed | Image by www.ggrgroup.com
Beaufort Scale For Wind Speed | Image by www.ggrgroup.com

There are other ways to measure the speed of the wind without the use of expensive equipment. The most notable of these methods is the “Beaufort Wind Scale” which uses the effects of the wind for a visual measurement of the wind speed. Examples go from 0 (calm) to 10-11 Storm Force winds causing widespread damage. There are various weather products for winds available including a global view of winds and a U.S. view.

Saffir-Simpson Hurricane Wind Scale | Image by www.earlyalert.com
Saffir-Simpson Hurricane Wind Scale | Image by www.earlyalert.com

We also talk about the sustained wind speeds in hurricanes. This one is called the Saffir-Simpson Hurricane Wind Scale. It has 5 categories from 1) 74-95 mph to 5) above 156 mph. These winds and other data are measured by an instrument package called a “Dropsonde” which is dropped into a hurricane from a “Hurricane Hunter” aircraft which is a specially outfitted WC-130J wide-body plane.

Air Force WC-130J Hurricane Hunter | Image by commons.wikimedia.org
Air Force WC-130J Hurricane Hunter | Image by commons.wikimedia.org

If you are wondering why they use a bulky, old, prop-driven airplane instead of a jet aircraft the answer is simple. The C-130J is very stable, even in hurricane force winds, because of its bulk  and those four propeller-driven engines. They also have to be able to fly a steady slow course back and forth over a grid to take those measurements. The dropsonde is literally dropped from the plane into various parts of the hurricane, including the eye itself, so the instrument package can relay its radio signals back to the plane with the data collected.

California Wildfires | Photo by pictzz.blogspot.com
California Wildfires | Photo by pictzz.blogspot.com

There is a particular wind that has been in the news lately called the “Santa Ana Wind.” It is defined by the National Weather Service as “a weather condition in southern California in which strong, hot, dust-bearing winds descend down to the Pacific Coast around Los Angeles from inland desert regions.” These winds along with dry weather conditions set up the perfect scenario for wind-driven wildfires to build and thrive. That’s been the case recently with many wildfires occurring at the same time in southern California. So we have wind that cools us on a hot day, wind that makes the winter cold temperatures feel even colder, winds that generate electricity on a wind farm, and the winds that spread wildfires among others.

Let me know what you would like me to talk about or explain. You can comment below or email me at: [email protected].