A Gift from August

August, long renowned for its heat, arrived overnight behind a cold front, bringing cool, misty weather to central Missouri.  Ahead of that front, heavy rain fell across Columbia, a welcome dose of moisture during this long, brutal summer.

While we certainly appreciate that a dramatic change in weather has arrived with the new month, there is little doubt that the heat will return as the front heads east.  But, for now, the cool respite will facilitate some much-delayed yard work.

Since it is the last meteorological month of summer, August invites us to look ahead to the glorious season of autumn.  Unfortunately, climate change is pushing back that transition and, before long, August may represent the midpoint of a prolonged summer season. 

Heat-Seeking Raptors

On this hot, humid afternoon in central Missouri, a trio of Mississippi kites soared above our Columbia neighborhood, feasting on insects.  Their energy under such conditions is impressive.

After nesting and summering across the Southern Plains and Lower Mississippi Valley, they will escape to South America for another summer in the Southern Hemisphere, traveling through hot climes along the way.  When you feed primarily on flying insects, it is best to be where they thrive.

While their seasonal movements are instinctual, these kites are certainly unfazed by weather that many, if not most humans, find oppressive.  Then again, they are not subjected to dire heat advisories. 

Return to Humidity

When we left Hays, Kansas, just before dawn this morning, it was already 75 degrees F, down from 99 degrees F the afternoon before.  Fortunately, as we traveled east, cloud cover persisted and the temperature  remained stable.

Even better, by the time we reached Junction City, rain began to fall, persisting throughout our journey across the Flint Hills.  Holding the temperature in the low 70s F, the rain was also psychologically beneficial after almost a month of intense sunshine and dry heat along the Front Range.

Beyond Topeka, however, the sun returned and the temperature gradually climbed into the upper 80s by the time we reached Columbia, augmented by Midwestern humidity as we entered a southerly flow from the Gulf of Mexico.  The moist air will feel good for a few days before I begin to miss the semiarid climate of Colorado. 

Growing without Water

As we left Metro Denver this morning, we observed a fleet of earth movers, clearing a swath of prairie east of the city.  Of course, this is in preparation of a new suburban development, perhaps twenty miles from the downtown area.

Having just experienced a record-low snowpack in the mountains, a nearly snowless winter in Denver and an extremely hot and dry summer to date, one wonders what the developers and city planners are thinking.  Already in a stage-one drought as the work begins, the Metro Area faces severe water shortages in the not-too-distant future.

Cities throughout the American Southwest are experiencing the same problem yet they continue to expand and place even more demand on limited water resources.  As our climate warms, a widespread crisis is bound to occur.  Perhaps a volcanic winter will rescue our species at some point. 

Night Rescue

A month past the summer solstice, our days are noticeably shorter.  As we endure a long period of severe heat, the longer nights cannot arrive soon enough.

Indeed, this astronomical rescue from sunlight will be the ultimate solution to the heat exhaustion that is affecting populations across the Northern Hemisphere.  Though we usually take this annual transition for granted, it will be especially welcome this year (and likely for many years to come).

No doubt, we will complain about the incursions of winter when they arrive but we can more easily prepare for them; besides, as our climate warms, they may disappear altogether.  For now, bring on the darkness!  

An Unfair Monsoon

Following two weeks of bright sunshine and severe heat, the annual Southwest Monsoon finally reached the Front Range urban corridor earlier this week.  Its scattered thunderstorms have dropped flooding rains in some areas while other locations (including our Littleton farm) have received little, if any, precipitation.

Such is the nature of the Monsoon.  Unlike the widespread, upslope rain and snow storms of spring, this river of moisture is less predictable.  Of course, between now and early September, most of us will receive some vital precipitation but the gift will likely be uneven, reflecting the effects of our varied terrain and the mountain wall to our west.  But we'll take what we can get.

Life is not fair, nature is not fair and the Monsoon can be frustratingly unfair. 

Morning Relief

As excessive heat and drought continue to plague the Front Range urban corridor, early mornings offer the only relief.  Due to the elevation and dry air, overnight cooling produces a few hours that invite outdoor activity.

This morning, just before sunrise, I took a walk along the South Platte River.  As low as I have ever seen it, the rock laden stream attracted a mix of waterfowl and waders in addition to a lone raccoon that foraged in the clear shallows.  Songbirds were still rather quiet and inactive, represented by only a couple of chickadees and a northern yellow warbler.

But while the wildlife was limited, a steady, north, cool breeze offered hope that our weather might be finally changing.  Indeed, the first taste of the annual Monsoon is expected over the next few days as afternoon highs dip back into the 80s F and scattered thunderstorms blossom along the Front Range.  We are surely hoping that forecast is accurate. 

Weather History

In the past, we were often informed of significant or record-breaking weather events that occurred on that specific date.  Some of the events were tragic while many were simply nostalgic.

In the present, severe weather seems to occur on a daily basis.  Following recent, deadly heat across most of the country, worsened by ongoing wildfires throughout the drought-plagued West, excessive rain has produced severe flooding throughout the Texas Hill Country over the past 24 hours.  No doubt, other sites of flash flooding will be reported across the South as warm, humid air flows northward from the Gulf of Mexico.  While a strong El Niño and copious African dust have reduced tropical development in the Atlantic Basin to date, we are yet early in the Hurricane Season.

As our climate continues to warm, we will be watching severe Weather History unfold on a daily basis, throughout our country and across the globe.  Lead by an Administration that denies the reality of global warming, we will be unprepared for the onslaught, leading to unnecessary deaths and potential economic catastrophe.  Vote Democratic in November! 

Mother & Destroyer

The Sea is the mother of all life on Earth, which first evolved in her realm about 3.6 billion years ago.  It would not be until 450 million years ago that some species became terrestrial but a fabulous diversity of life still inhabits Mother Sea, much of which has yet to be discovered by humans.

Nourishing and sculpting terrestrial ecosystems with her weather systems, she also destroys habitats and human developments with coastal hurricanes, severe inland storms and flooding rains.  Indeed, as our climate warms, these destructive events will intensify.

Furthermore, as her component oceans open and close, earthquakes, tsunamis and volcanism alter terrestrial landscapes and destroy regional life; the recent earthquakes in Venezuela demonstrate a risk that stretches across the globe.  The Sea, an essential component of Life on Earth is both generous and destructive; we could not live without her but often succumb to her power.  

Thousand-Year Floods

Following episodes of severe flooding, as occurred in southeast Missouri and southern Illinois yesterday, references are made to a "thousand-year flood," indicating that such an event is expected no more often than every thousand years.  Of course, such an expectation is based on meteorological data that has accumulated over the past Century or so.

Unfortunately, we are now in a different atmospheric environment, courtesy of global warming that was triggered by the Industrial Revolution.  Earth's seas and atmosphere are steadily warming, saturating the air that moves above the Continents and archipelagos.  Storms, ignited by atmospheric clashes along an energized jet stream, often drop copious amounts of rain and, should the storms "train" across the same areas, severe flooding occurs.

Such destructive floods are becoming more common and will only increase in frequency as our climate continues to warm.  Efforts to reverse that trend are not currently sufficient, especially in the U.S., and we ignore the risk of living on floodplains and barrier islands.  "Thousand-Year Floods" have become annual events. 

The Drought and Waders

Non-birders may be surprised to learn that a wide variety of herons, ibis and egrets summer in or visit the Front Range urban corridor.  Indeed, great blue herons and black-crowned night herons are common permanent residents while great egrets, snowy egrets, white-faced ibis and cattle egrets are common summer residents and migrants.  Both American and least bitterns are uncommon summer residents and a host of waders are rare summer visitors; the latter include tricolored herons, yellow-crowned night herons and white ibis.

Most of these waders favor shallow mudflats and marshlands along the border of ponds, lakes and rivers and are thus not obvious to those who visit wetland habitats.  This summer, however, the drought has severely lowered the water level in lakes and rivers, drawing herons and egrets out into the open in search of fish and aquatic invertebrates.

As a result, I have encountered far more waders in Littleton than I have seen in past years.  Just this morning, I saw ten snowy egrets, five black-crowned night herons and a few great blue herons along a short stretch of the South Platte River.  Of course, such rewards do not make up for a crippling drought but its effects are worth noting. 

Smoke from Distant Fires

Haze from wildfire smoke has gradually increased along the Colorado Front Range over the past week.  There are at least 7 active fires in Colorado and 6 in Utah, not to mention a couple in New Mexico and many farther west.

Of course, the ongoing Western drought is primarily responsible for the large number of fires, most of which have been ignited by lightning or human carelessness.  So far, the annual Southwest Monsoon has been meager at best, bringing little moisture to the dry terrain.

Due to our local drought and poor air quality from the wildfires, most firework displays have already been cancelled throughout Metro Denver.  Parades, cookouts and festivals will have to suffice. 

A Voice of Promise

As we enter the heart of summer in the midst of a heat wave and bathed in smoke from the Utah fires, it was reassuring to hear the soft hooting of a great horned owl last evening.  Common throughout most of the Western Hemisphere, these large owls are regular visitors to our Littleton farm though, to my knowledge, they have never nested on the property.

The rather muted voice of last evening's visitor suggested it was a young owl, born last winter and now on its own after several months of parental assistance.  The soft hoots, from a large tree near our house, certainly did not match the loud, confident banter of adult owls in late autumn and winter.

Feeding on a wide range of mammals, from mice to opossums, and on snakes, lizards and birds as well, great horned owls tend to be silent loners throughout the warmer months.  Last evening's hoots thus seemed to promise that cool, crisp October nights lie ahead.   

A Ridge of Heat

Following a week of stormy weather along the Colorado Front Range and across the Central Plains, an atmospheric ridge will build in by tomorrow, bringing sunny, hot conditions within its expanding dome.  Here in Metro Denver, we expect highs in the 90s F for the next week.

As the ridge, produced by a northward arc of the jet stream, expands across the Plains and into the Midwest, Pacific storm systems will be directed along its rim, bringing thunderstorms to the Northern Plains and Upper Midwest.  Meanwhile, behind the dome, an atmospheric trough (a dip in the jet stream) will bring cool, moist air to the drought-plagued West; while snow is expected at high elevations, strong winds and lightning may actually increase the risk of wildfires across the dry terrain.

Until the ridge shifts eastward, the Southwest Monsoon, a vital source of moisture throughout the Four Corners Region and the Southern Rockies may be shut down.  Let's hope the ridge does not dally. 

Extreme Weather & Climate Change

Weather extremes have characterized most of the U.S. this year.  This week's flooding across the Southeastern States has been record-breaking as some locations have received almost three feet of rain.  Ironically, some of the deluge has occurred in areas that had been plagued by drought for many months.

Farther north, severe thunderstorms with tornadoes, high winds and large hail have repeatedly raked the Great Plains and Upper Midwest.  This weekend, another round of severe weather will develop across the High Plains, moving through the Ohio Valley and the Mid-Atlantic Region over the following days.

Extreme heat, warm oceans and a powerful, unruly jet stream combine to produce these dangerous weather conditions.  More than typical, seasonal storm systems, we are witnessing the effects of a warming climate.  Though its effects may vary over the years, these extreme weather events will surely become more common and efforts to reduce damage and deaths will be imperative. 

Severe Weather on the Plains

From a weather perspective, it is always an adventure to travel across the Great Plains of North America.  This morning, after creeping through heavy rain and dodging thunderstorms in Missouri, I was greeted by a clear blue sky as I crossed into Kansas.  While such an abrupt change is usually encountered when a strong cold front pushes into warm, humid air, the air in Kansas was hot and dry, indicating that I had entered a dome of high pressure.

Indeed, the skies were nearly cloudless until I reached Junction City; from that location, I could see clouds off to the northwest, likely forming along the northern edge of the dome.  Reaching the southern extent of that cloud mass in Salina, I was more captivated by conditions on the ground; widespread damage to road signs, trees and a few ranch buildings looked as if one or more tornadoes had recently raked that city.

While the heat and sunny skies persisted all the way to Hays (my overnight rest stop), the clouds north of my route continued to expand and most of northeastern Kansas is now under a tornado watch; in addition, a line of thunderstorms has formed from southwestern Kansas to the tornado watch zone (erupting along the western edge of the heat dome).  Another spectacular light show is anticipated.

Addendum:  The damage that I witnessed in Salina was due to 113 mph wind gusts associated with severe thunderstorms on June 8. 

The Central American Gyre

From May to June and from September to November, a large, relatively weak zone of low pressure settles over Central America, coinciding with the rainy seasons in that region.  Of little consequence itself, this gyre may interact with tropical waves arriving from the Caribbean or from the South Pacific.

This interaction may produce tropical depressions which, under the right conditions, may develop into tropical storms.  Of course, if wind shear does not intervene, these storms may then become hurricanes, either in the Gulf of Mexico or along the west coast of Central America.

This meteorological sequence is often responsible for Gulf of Mexico tropical storms and hurricanes that develop early and late in the Atlantic Hurricane Season (June to November).  Typically, a tropical depression develops in the southwest Gulf of Mexico and moves northward; if high pressure has settled over the Gulf, suppressing wind shear, the depression becomes a tropical storm or hurricane as it moves across the warm Gulf waters.  According to current forecasts, such a development may occur later this week.  

Colorado's Severe Weather Month

As if on cue, a swarm of severe thunderstorms ignited along the Front Range yesterday afternoon, dropping torrential rain and large hail and, in one case, spawning a brief tornado.  Fortunately, our Littleton farm was sparred any damage but we also missed out on the rain.

While severe weather usually begins to decline across the Great Plains and Midwest by early June, it is ramping up in northeast Colorado.  Indeed, tornados are most common during this month, primarily affecting the High Plains of the Colorado-Wyoming-Nebraska Tristate.  Of course, the Front Range urban corridor is not immune to these storms and hail damage can be significant.

How global warming will affect this traditional weather pattern and the Southwest Monsoon that follows remains to be seen.  While the moisture is almost always welcomed, we could do without the powerful winds and large hail that June too often delivers.  

Light Show on the Great Plains

Arriving in Hays, Kansas, late yesterday afternoon, I saw a thunderstorm approaching from the south.  After crossing the east side of town, it eventually merged with a large cluster of thunderstorms over Russell, about 25 miles east of Hays.

From my room, I was treated to a broad view of the Great Plains to the northeast and watched as the Russell storms spread northward and eastward.  Once the sun set, the lightning show was spectacular, with some cloud-to-cloud strikes radiating back toward Hays.  Consulting the weather radar, I found that a chain of severe thunderstorms stretched from Wichita, Kansas, to the Black Hills of southwestern South Dakota.  In addition, a mass of storms in northeast Colorado extended the turbulence westward; indeed, as was evident on Flight Aware, cross-country air traffic was funneled north of the Black Hills or south of Wichita.

The light show from this massive band of storms continued late into the evening, well past my usual bedtime.  But one of nature's most awe-inspiring spectacles was well worth a modest loss of sleep. 

 

Waders in the Shallows

Returning to Eagle Bluffs Conservation Area this morning, a friend and I found that the water levels have continued to fall and that vast shallows spread out from the central channel and along the primary drainages of the refuge.  Not surprisingly, these conditions attracted a large number of waders (61 great blue herons and 37 great egrets), perhaps the most I have ever observed at this floodplain preserve.

As summer sets in, waterfowl were limited to the resident Canada geese and a lone, male wood duck.  Killdeer were the only "shorebirds" and turkey vultures were the sole raptors.  Dickcissels, the most abundant songbirds, called from the drier grasslands while many summer residents, hidden in the foliage, were identified by their songs; these included yellow-breasted chats, yellow warblers and common yellowthroats.  More conspicuous were indigo buntings, fish crows and mixed flocks of swallows.  A single cormorant, finding the water too shallow for diving, flew across the refuge, heading for deeper fishing grounds.

Having recovered from a prolonged drought, this wetland refuge must now rely on periods of heavy rain to sustain its rich ecosystem.  Of course, human visitors, ourselves included, hope that summer storms regularly douse the floodplain.