July 2005 Archives

To no one’s surprise, July ended up to be warmer and drier than normal in Chicago. Though severe thunderstorms brought some much-needed rain to scattered localities, the overall drought worsened across the area during the month. The hot summer continued with seven 90° days at O’Hare and 10 at Midway during the month, highlighted by the region’s first 100º day in six years on July 24 when O’Hare soared to 102º and Midway to 104º.
August’s opening days promise a continuation of this hot, dry pattern with four consecutive days in the 90s expected through Thursday, along with little chance of significant rainfall.
Rain is falling in other parts of the nation. Up to 4 inches of rain flooded the streets of Sylvania in east-central Georgia Sunday, while vehicles were stranded in up to 3 feet of water in east-central North Carolina near Greenville after heavy thunderstorms passed through the area.

After a short respite, heat and humidity will return to Chicago this week for what appears to be a lengthy stay.
Afternoon maximum temperatures should climb into the 90s today—an event that promises to repeat itself each afternoon through Thursday.
For the most part, prospects for precipitation remain bleak, though an isolated thunderstorm could develop on a hot and increasingly humid Monday afternoon. The week’s best chances for rain will occur Thursday night as a cold frontal passage brings the city another refreshing break after a week of hot weather.
With the recent demise of Tropical Storm Franklin, the Atlantic Basin is currently tropical cyclone-free, but things could change quickly in the next day or two if a strengthening tropical wave approaching the Windward Islands becomes the eighth storm of the season: Harvey.

More heat’s on the way. Temperatures and humidities will remain comfortable Saturday, thanks in part to easterly winds off Lake Michigan. But, with the ninth weekend of meteorological summer 2005 underway, the area is bracing for a new round of hot weather. A huge, rain-free dome of hot air continues to develop across the nation’s mid-section. Readings soared above 100° in parts of the Plains Friday, and this hot air is to begin building eastward.
Though daytime highs here won’t be as extreme as last Sunday’s 102°, surging humidities promise to make the five days of 90s predicted Sunday through Thursday rather uncomfortable: Gulf Coast-level dew points near 70° on the hottest of those days may send heat indexes near 100°.
Six of eight summer weekends this season have posted temperature surpluses, averaging nearly 5 degrees above normal. It’s likely this weekend will become the seventh to finish above normal.

Chicagoans are treated to another day of comfortable temperatures and humidities Friday. The day’s strengthening NE winds off Lake Michigan—and of Canadian origin—limit highs in all but far west and south suburban areas to levels below the normal high of 84°.
For a second consecutive day Thursday, the afternoon high (79°) here failed to reach 80°. In a summer with temperature stats which have so consistently been on the high end of the spectrum, it’s little surprise this summer’s tally of just 11 days in the 70s (26 is the long-term average since 1871 by this date) is so rare. Only two of the past 135 years—1944 and 1949, with 10 and nine days of 70s respectively—have produced fewer “cool” daytime summer highs.
The chill was more evident in the upper Midwest early Thursday. There, morning lows dipped to 38° at Tower and 44° at Embarrass—both in Minnesota.

It was the East Coast rather than sections of the Midwest which baked in record triple-digit heat Wednesday. For the first time in weeks, temperatures backed away from the 90s and 100s across the nation’s heartland. The dramatic pullback included Chicago’s September-level 74° high at O’Hare—the city’s lowest daytime high in nearly six weeks. It hasn’t been cooler here since 71° on June 18. The retreat was especially noticeable in a summer over which daily highs have finished, by a margin of nearly 6 to 1, above rather than below normal. The nearly two-month period since June 1 now ranks 6th warmest of all comparable periods on record here since 1871. It is also the 7th driest June 1-July 28 period in that 135 year span—and that’s with Tuesday’s beneficial rains included.
The heat was intense to the east Wednesday. Record highs included 100° at New York’s La Guardia Airport, 101° at Newark, N.J., and 102° at Raleigh, N.C.

Had they happened just weeks ago, Tuesday evening’s drenching downpours would have constituted a “million-dollar rain” for northern and central Illinois corn farmers, who have watched four months of drought ravage the region’s corn plants. But, while the rains are too late for the area’s decimated 2005 corn crop, WGN Radio agriculture broadcaster Max Armstrong says soybeans may be another story. Soybean pods are reaching a critical stage in the days and weeks immediately ahead, says Armstrong—setting and filling out. Rain is essential for success in this process and will play a major role in determining the ultimate soybean yield at harvest time. Precisely how much Tuesday’s rains have helped will become clearer in the weeks ahead.
Unusual by summer standards because of its uniform distribution, the rain was the heaviest to fall in the city in two months (since 1.26” on May 19).

SEVERE THUNDERSTORM STRIKES ARLINGTON HEIGHTS MONDAY EVENING

Monday evening a severe thunderstorm packing winds to about 60 m.p.h., torrential rainfall and lots of thunder and lightning raced through the northeast portion of Arlington Heights. Rainfall totaled .92" which fell in blinding torrents in a span of just 15 minutes. This morning the streets are littered with twigs, leaves and small branches which succumbed to the storm's strong, gusty winds. The lightning during the storm was intense with many cloud to ground strikes. One clap of thunder was so loud that our whole house shook. I was sure that it had hit close by and this morning I discovered what had happened. A large tree in nearby Wildwood Park had been struck with a large limb split open and nearly severed from the tree.

A tree in Wildwood Park struck by lightning in Monday evening's storm.

Burn marks where lightning bolt hit

Another close-up view of burn marks

Summer’s never been hotter at Midway Airport. The 77.2° average temperature at the site since June 1 is the hottest on the books since observations began there in 1928. The reading is 4.7 degrees above the 77-year average and more than 6 degrees warmer than last year.
Some active clusters of thunderstorms combined with winds off the lake spared Chicago the brutal heat through which downstate residents suffered Monday. Moisture levels there were more typical of a tropical rain forest than the Midwest. In combination with triple-digit air temperatures, heat indexes soared into dangerous territory, reaching 110° or more in locations as close as Bloomington (111°) and Pontiac (116°).
Chicago’s relatively restrained 89° high at O’Hare was offset by the year’s muggiest dew points. At 3 a.m. Monday, O’Hare’s dew point hit 76°, while Northerly Island on the city’s lakefront soared to 79° around 9 p.m. Monday.

From shortly after noon until early evening Sunday, temperatures hovered at or over 100° across the Chicago metro area. Strong westerly winds drove a warm tongue of low-level heat from the mid-Mississippi Valley across northern Illinois, but these strong winds did alleviate the potentially deadly effects of a higher heat index by mixing drier air aloft to the surface.
As a result, dew points dropped from the mid 70s into the lower 60s—in effect cutting the potential 115°-120° heat index values back into the 103°-107° degree range. For example, veteran weather observer Frank Wachowski reported at Midway Airport that the dew point at 8 a.m. was 75°—the highest of the summer—but as the strong winds mixed in drier air from aloft, the dew point slowly but steadily fell, reaching 63° by mid-afternoon. This diluting of moisture near the ground significantly reduced reported heat index values by approximately 15 degrees.

At 2:52 p.m. this afternoon the thermometer at O'Hare Airport reached 102º making today the hottest day in the city since the mercury peaked at 104º on July 13, 1995 during Chicago's tragic killer heat wave. That same day Midway Airport broiled at 106º. Midway observer Frank Wachowski reports a high so far today of 104º recorded at 2:40 p.m. equalling the 104º high reached there on July 30, 1999.

Steve Kahn WGN-TV/Chicago Tribune Meteorologist

IT'S OFFICIAL-- FIRST CHICAGO 100S IN SIX YEARS--TEMPS STILL CLIMBING

At 1:08 p.m. this afternoon the city's official thermometer at O'Hare Airport reached 100º. This is Chicago's 61st official 100º day on the books and the city's first since the high of 101º reached on July 30, 1999.

Midway Airport observer Frank Wachowski reported a high of 103º
so far this afternoon that was recorded at 1:45 p.m. CDT. With brisk west southwest winds, there is also no lake cooling with Northerly Island also reaching a high temperature of 100º. With several hours of peak heating ahead, it is likely that readings will surge even higher.

The record high temperature for today is 105º recorded in 1934 and is also Chicago's all-time official record high.

Seventy one years ago today, on July 24, 1934, Chicago established its all-time official high temperature of 105º, and today’s triple-digit maximums should not be far behind. A hot air dome that sent temperatures soaring to as high as 110º in eastern South Dakota Saturday will surge into the Midwest today, bringing Chicago its first 100º weather in six years.
A long-lasting line of thunderstorms called a derecho that packed winds as high as 85 m.p.h. formed just north of the area of heat and humidity Saturday, sweeping out a swath of wind damage from northeast South Dakota to southeast Wisconsin. The storms dissipated just before reaching northeast Illinois, depriving this region of much needed rain, but sparing the area from power outages just before the intense heat moves in.
Hot weather will last into Monday before northeast winds bring much more comfortable conditions for the remainder of the week.

Chicago hasn’t recorded a triple-digit high since July of 1999. That changes Sunday as SW winds whisk intensely hot air into the area, a development which may well produce only the 61st official high at or above 100° here since records began in 1871. (Note: The heat-enhancing “urban heat island” effect has led to a greater number of 100s at the Midway Airport observation site, which has logged 83 days of triple-digit readings since 1928). Advisories for heat have been posted by the National Weather Service across 18 states this weekend from South Carolina west to Texas.
The effects of hot weather led to the hospitalization of 18 people in Paducah, Mayfield and Fulton, Ky. Heat indexes there ranged from 105°-115°. Drought conditions continue to make news. Rainfall at the Quad Cities so far this year is the driest since records began—drier than the Dust Bowl years of the 1930s. And Duluth, Minn., has experienced the driest July in the past 57 years.

Downstate Illinois and Indiana are in the grip of one of the hottest air masses in years and there’s no relief in sight until the middle of next week. It’s the same intensely hot air mass expected to sweep into Chicago Sunday and Monday. Even as clusters of downpour-generating thunderstorms whacked Chicago’s northwest and southeast suburbs Thursday, afternoon heat indexes soared above 100° for a second day as close as Kankakee (102°) and Bloomington (112°). Dewpoints, a measure of atmospheric moisture—considered uncomfortable at 70°—surged to 80° downstate. The atmosphere rarely holds more moisture in the Midwest.
Thursday’s powerful storms drenched Lafayette, Indiana with 1.59” while 0.60” fell at Valparaiso. By contrast, South Bend received only 0.20”, underscoring the selective nature of summer rainfall.

WHAT IS A GUSTNADO?

A possible gustnado caused considerable damage in portions of Lake County Illinois early Wednesday afternoon near the town of Wildwood as a line of severe thunderstorms raced through the area. The gustnado typically forms along the leading edge of a thunderstorm outflow boundary called a gust front. Below is a feature from the Chicago Tribune weather page archives done several years ago explaining this unusual meteorological occurrence.

Wednesday’s thunderstorms unexpectedly held together after crossing the Mississippi and surged into Chicago with the most rain in nearly 5 weeks. The price to pay was scattered severe weather, including widespread tree damage and a gustnado (a mini tornado at the leading edge of a thunderstorm) in Lake county, Ill., and 69 m.p.h. winds at Coal City southwest of Joliet. The reward was 0.60 in. of rain at O’Hare, the heaviest rain there in two months. Statewide the drought has crippled the corn crop, with 55 percent in poor to very poor condition. Last year at this time, only 2 percent of the crop suffered.
Meanwhile, heat in the West continues to build into the Plains. 100°+ temperatures were common across Kansas and Nebraska, and reached as far east as Quincy, Ill. A weak cold front inches into the area Friday, delaying the onset of scorching heat here until Sunday and Monday. Significant heat relief finally settles in next Wednesday.

Even with the passage of a cold front Monday and the shift to northwest winds that followed, both O’Hare and Midway managed to reach 90° or higher on Tuesday, the fourth consecutive day of 90°+. Once again, low dew points made the heat tolerable, this time due to a fresh change of air mass rather than drought-induced dry air of days past.
Cooler air in the 80s wedged south into Minnesota and Iowa with this cold front, but west of that especially hot air continues to build in the high Plains and Rockies. Las Vegas broke six high temperature records Tuesday, including 117° which tied their all-time high set July 24, 1942.
This heat continues its unstoppable march eastward in upcoming days, reaching Chicago on the weekend. The first relief from these torrid temperatures finally arrives next Tuesday, along with a chance for meaningful rain.

A weak cold front swept through Chicago during the lunch hour Monday, but once again, significant rain failed to materialize until the system was south and east of the city. O’Hare received no rain, while Midway collected only .08". Already the driest summer on record to date, a scant 0.2" of rain has fallen at O’Hare in the 7+ weeks since June 10. Meanwhile, heat statistics are adding up. O’Hare’s 91° and Midway’s 92° are the 13th and 19th days respectively of 90° days in Chicago this summer, more than the last two summers combined.
Monday’s cold front provides one day of relief from the ongoing heat. Another brief cold frontal passage is likely again on Thursday, with oppressive heat to follow over the weekend and into next week. Rain with frontal passage is likely on Thursday, but the computer models have not distinguished themselves and have consistently under forecast temperature and over forecast rain all summer.

O’Hare’s 97° on Sunday was the hottest day since 101° on July 31, 1999. Again, the heat was made more tolerable by low dew points. The heat should break on Monday with the passage of a cold front and a gradual shift to northwest winds—but the front is weak, and temperatures will remain above normal Tuesday.
Today, Chicago enters the warmest period of normal temperatures for the year, 10 days with an average a high of 84° and a low of 64°. After the brief heat relief, temperatures turn back up on Wednesday, climbing each day to follow and peaking around 100° next weekend.
Meanwhile, the extreme drought retains its grip on the area. Rain with Monday’s cold front will be scattered, and even the computer models are backing off on totals, predicting only a scant few hundredths of an inch. Thursday now looks like a better bet for rain as another weak cold front approaches from the northwest.

MCDONALD CREEK- BONE DRY

The drought of 2005 is taking its toll. Since May 1, I have measured only 1.5 inches of rain at my house, and more than half of that fell in just 30 minutes during one heavy thunderstorm on the 4th of July. Area soils are parched and cracked and unwatered area vegetation is severely stressed and in some cases dying.

Having lived in the northeast part of Arlington Heights for more than 35 years and frequently crossing and viewing nearby McDonald Creek, I have never ever seen it bone dry like I did today on my daily walk around Lake Arlington. After a torrential rain McDonald Creek can be a raging torrent, but usually it is a lazy, low flow creek. However, today for the first time in my memory, McDonald Creek is totally dry, another casualty of the increasingly severe Drought of 2005.

A view of McDonald Creek

McDonald Creek as seen from the west bridge leading to Lake Arlington

Saturday’s 93° at O’Hare—the highest so far this July—brought the 2005 total of 90° days to 11, with 17 days at Midway. Fortunately, afternoon dew points dropped to the low 60s and upper 50s, making the heat more tolerable. Low and fluctuating dew points are often a characteristic of drought summers. Sunday should reach the mid 90s for all areas but the lakefront, while light southwest winds pump in enough low level moisture to keep dew points in the uncomfortable range.
After a muggy night, Monday starts out warm. Clouds move in from the west with the best chance of widespread rain in weeks. The caveat is drought; it’s not unusual to see a good chance of rain in computer models dissipate before reaching a drought area.
Meanwhile, major hurricane Emily crosses the Yucatan late Sunday into Monday with a steady northwest track into the Mexican mainland. There’s little chance that any hurricane moisture eventually reaches Chicago.

Across drought-stricken northeast Illinois, Friday’s “hit and miss” thunderstorms were mostly a miss. The day’s muggy air managed to generate only a single thunderstorm of consequence, but what an event it was. An early afternoon deluge put down 2 3/4 inches of water just to the northeast of Kankakee. In the immediate Chicago area, however, showers were so brief and light that they went practically unnoticed.
The world’s heaviest one-month rain total, an incredible 366.14 inches, happens to be a July event. That rain, ten times Chicago’s average annual total, all came down in July, 1861, at Cherrapunji, India, and it’s a record that survives to the present.
At the U.S. South Pole Station in Antarctica, temperatures in July of 1997 averaged 86.8ºF below zero, thereby establishing a new record for the world’s coldest month.

That’s the word from Max Mayfield, Director of the National Hurricane Center in Miami. And now that the 2005 hurricane season has gotten off to a record fast start, his admonition is especially relevant.
Dr. Mayfield is referring to the tendency of the public to focus its attention on the narrow line defining the predicted movement of a hurricane core rather than the “cone” of possible movement of the storm system.
Mayfield also emphasizes that tropical storms and hurricanes are not discrete points on a map. Rather, they are sprawling weather systems that produce dangerous and damaging weather conditions in a belt sometimes 300 miles on either side of the center path.
A hurricane’s arsenal of potentially deadly weapons includes high winds, coastal storm surge, isolated tornadoes and inland river and flash flooding.

Popularly, “the Dog Days of Summer” refer to the hottest and most humid portion of the summer season—the period extending from early July into mid August. It’s a time of relative inactivity and stagnation, and even the weather seems to slow down. That’s certainly the case right now.
Jet stream winds, important because they steer air masses and storm systems and, broadly speaking, keep weather systems moving along, have shifted north into Canada. Computer models say that’s not likely to change significantly in upcoming days.
Locally, the atmosphere has become lethargic. The remnant remains of Hurricane Dennis have stalled over the Ohio Valley and are gradually fading away. Lingering showers, too, are dissipating. Hazy, warm and humid air now in residence will stick around, and grow even warmer this week as the hot July sun works on it.

“Everybody talks about the weather but nobody does anything about it.” That familiar assertion, usually credited to Mark Twain, was most likely written by his brother-in-law, Charles Warner, in an editorial in the Hartford Courant.
“But,” as former Chicagoan, Dr. Keith (“The Weather Doctor”) Heidorn has said, “it’s moot, because someone actually did something about the weather back in 1902. His name is Willis H. Carrier and he invented air conditioning.”
Air conditioners, humming in the warmth and humidity of recent days, will soon be humming more vigorously. It’s a testament to the warmth of air now in residence that afternoon temperatures are having no trouble climbing well into the 80s even under the clouds and showers associated with the remains of Hurricane Dennis.
The return of sunny days later this week spells more 90° weather for the city.

Today the WGN crew spent the day on the Glacier Bay Boat Tour, with fellow travelers at the Glacier Bay Lodge and the dedicated staff aboard our vessel, including National Park Service interpreter Mary Lou and native Chicagoan Joe Seebacher, who grew up just a few blocks from the WGN studios.

In the few days that we have been here, the most common denominator is just how friendly and welcoming everyone is here. Regardless of your origins, Alaska brings out the best in people.

The boat tour departed from Glacier Bay Lodge in Bartlett Cove and in one of the last truly wild areas of our country, we were able to see boundless amounts of native wildless right before our eyes. From the playful sea otters eating kelp to the cinnamon brown bear and her cubs taking a leisurely bath along the beach to the magnificent orca whales swimming alongside our boat.

However, the towering tidal glaciers proved the most awe-inspiring scene of the day as the thunderous sounds of calving pieces of ice hit the sea and the precipitous peaks of the glacier appeared as an entrance to a mighty fortress. It is indeed a force of nature to be reckoned with.

As we have discovered already at Lituya Bay, Alaska is full of examples of rejuvenation. It little more than 100 years ago, much of Glacier Bay was under ice. Now, it is teeming with wildlife and vegetation, undisturbed by the advancing world around it. It truly is one of the best kept secrets in Alaska.

Tomorrow, we will be traveling by train to the town of Seward on the Kenai peninsula where we will be talking to survivors of the 1964 tsunami and visiting Exit Glacier in the Kenai Fjords National Park.

Note: Due to limited internet access, photos and videos of our daily adventures will be delayed.

90º is the benchmark definition of a hot day for most of us, and that was the temperature logged at Midway Airport yesterday. It was the city’s 16th 90° occurrence this summer. While not a record (that distinction belongs to the sweltering Dust Bowl summer of 1934, which had 24 90° days through July 12), it is significant in that it equals the combined number of hot days logged here in all of 2004 and 2003.
Clouds spinning out of the dissipating remnants of Hurricane Dennis, now a sprawling but weak area of low pressure over southern Illinois, have put a temporary hold on hot temperatures locally. That’s a consolation, but what we really need is the system’s rain. Unfortunately, metropolitan Chicago finds itself on the extreme northern flank of the
rain area and any showers that do find their way to the area will a tease but nothing more.

After making landfall at Pensacola, Fla., Sunday afternoon with winds between 115 to 120 m.p.h., Hurricane Dennis quickly weakened as it moved inland. By noon today the remnant low center is expected to be in northern Mississippi and headed for the junction of the Ohio and Mississippi rivers Tuesday. A broad area of heavy rain is forecast to accompany and precede the low center. With the jet stream far to the north in Canada, upper-level steering winds are very light, enabling the low to meander through southern Illinois into Indiana—perhaps dumping copious rains along its path. Preliminary estimates call for as much as 8 to 10 inches of rain in that area by Thursday.
The longer this pattern takes to shift the low east, the better the chance significant rain will reach northern Illinois, where interaction with an approaching cool front could trigger a prolonged period of showers and thunderstorms in the Chicago area.

Roxane from Chicago had an encounter with a dust devil on Saturday July 9 in the Des Plaines area. As the dust devil passed over, her car shook and everything inside the car was flying about. Once it passed, Roxane was able to take this spectacular picture.

Photo by Roxane

Dust devils can occur on sunny, warm days when winds are light. An archived Ask Tom Why question will help explain how they form.

October 19, 1998

Dear Tom,
What are dust devils? When and where do they occur the most? Do they ever cause damage?
Nancy Morton Grove, Ill.

Dear Nancy,
Dust devils are small, vigorous whirlwinds that are seen moving slowly across the countryside. They form on sunny summer days when winds are light, and occur in open areas, over sandy or rocky fields, even large parking lots — where the sun has strongly heated the ground. Dust devils can be up to 100 feet in diameter, though most are much smaller, and they extend from the ground upward several hundred feet into clear air. Air within dust devils swirls around in a tight circle, clockwise or counterclockwise, and rises in corkscrew fashion, carrying aloft dust that enables us to see the wind circulation. They are not related to tornadoes (which extend downward from thunderstorm clouds) and their winds, 20-40 m.p.h., are too weak to inflict damage.

Copyright © 2005, WGN-TV

Steve Kahn WGN-TV/Chicago Tribune Meteorologist

The Chicago area is now classified as being in an extreme drought and the parched soils and lack of rainfall are taking a toll on area vegetation. Many thanks to viewer Bonny Goldberg of Park City, Illinois who sent this picture of a corn field located just north of Gurnee Mills. In her own words, the moisture starved corn field looks more like a "pineapple field."

Photo by Bonny Goldberg

Steve Kahn WGN-TV/Chicago Tribune Meteorologist

July 9, 2005 Sitka

The WGN crew including Chief Meteorologist Tom Skilling, producer Pam Grimes, web producer Amy Mowery and photographer Steve Scheuer begin our travels to Alaska today with a short stop over in Sitka, where we had the opportunity to interview Howard Ulrich, a survivor of the 1958 tsunami in Lituya Bay, near Glacier National Park.



47 years ago today, the father and his 7-year-old son survived the largest wave ever recorded, nearly 800 feet high, with a splash nearly 1,800 feet. It was so destructive that it literally stripped all vegetation off of the surrounding foothills near shore.



We then had the wonderful opportunity to meet with John Litten, who helped found the Alaska Raptor Rehabilitation Center. This amazing facility is the only one of its kind in Alaska and birds from all over the state are flown here to recuperate from various life threatening accidents and are either reintroduced into the wild or spend the rest of their life in this safe, yet native habitat. Not only do bald eagles reside here, but also red tail hawks and owls to name a few.



The center takes in more than 200 birds a year and has an indoor flight training facility that allows the rehab center volunteers to monitor a bird's progress and if its ready to be released into the wild. This is truly a must see facility in Sitka. For more information, go to www.alaskaraptor.org



Tomorrow the WGN crew heads out to Lituya Bay to see for ourselves the site of the 1958 tsunami and how the area continues to leave footprints of this tremendous natural disaster.

With dangerous killer Hurricane Dennis picking up energy from the warm seas of the Gulf of Mexico, latest forecasts Saturday evening called for a gradual strengthening of the storm with Catagory 4 winds well in excess of 130 m.p.h. a distict possibility when it makes landfall somewhere along the Gulf coast from the Florida panhandle to Louisiana later today. Storm surge waves as it hits could be as high as 12 to 14 feet. Four to 8" rains should touch the west coast of Florida and spread inland ahead of and with the storm center. Flooding rainfall will probably precede the weakening low as it moves north into the Middle Mississippi and lower Ohio River valleys Monday and Tuesday. Moisture associated with the remnants of Dennis could make its way as far north as Chicago later Tuesday and Wednesday just as a cool front moves through from the NW giving NE Illinois its best and probably only chance of rain this coming week.

Hurricane Dennis works its way north through the eastern Gulf of Mexico, dumping up to 10 inches of rain along the west Florida coast today and then is projected to move inland later Sunday, preceded and accompanied by additional heavy rains over Mississippi and Alabama. Once over land, Dennis is expected to weaken to a tropical storm Monday and become a broad low pressure system as it moves into the lower Ohio Valley Tuesday. As the low pressure area drifts east the following few days, Chicago is expected to lie on the northern fringe of the associated showers as they spread into southern and central Illinois midweek. The passage of a cool front Wednesday could produce scattered showers over northeast Illinois, but no significant relief to the now “extreme” drought is in sight. Daytime highs around 90° next week with generous periods of sunshine will mean continued significant evaporation and loss of water for stressed vegetation.

The Chicago area’s drought severity has moved from “severe” to “extreme” in the latest U.S. Drought Monitor report issued Thursday. The only category of severity which remains is “exceptional”—and the region may be headed in that direction unless much needed rains arrive soon. With slowly rising temperatures expected to build into real heat by early next week, conditions are sure to deteriorate. Officially, measurable rain has fallen only 38 days since March 1. That’s only two days more by this date than in the infamous 1988 drought. The long term average for measurable rain days since 1871 is 48.
Though drought is in full bloom across Illinois and northern Indiana, lake breeze thunderstorms erupted downstate Thursday afternoon. Doppler radar scans put cloud tops in several of the storms at 45,000 ft. and estimated rainfall over a small section of Livingston County at 4 and 5 inches.

A handful of small thunderstorms developed away from Lake Michigan Wednesday afternoon—and a few isolated storms may swipe locations west and south of the city again Thursday. The brief rains they produce fall far short of relieving this area’s drought. Besides affecting less than 10% of the area, these thunderstorms are fleeting—here one moment and gone the next. The downpours they produce are brief and highly localized. Prospects for an extended round of heat begin this weekend, suggesting the current dry pattern has legs and is likely to get worse as the mercury rises.
The weather is anything but dry in the South and Northeast.
Boston, chilled by NE winds off the Atlantic Wednesday evening, was drenched by more than 2" of rain. And, Tropical Storm Cindy’s remnants whipped New Orleans with 70 m.p.h. gusts spawning at least seven twisters in Alabama.

Drought

Dry weather that is withering Chicago and Illinois has prompted increasing mention of a word not often heard in this area - drought.

What is drought? In the United States the mention of drought brings to mind scorched lawns, parched fields and withered crops, dusty rural roads, dry wells, sluggish rivers, shrinking reservoirs, water restrictions and failing water supplies. In its extremes in some countries, drought means hunger, starvation and famine, human emaciation, mass migrations of peoples, even death. Sometimes drought has led to war.

There is no single definition of drought that is satisfactory for all situations. We may say truthfully that we scarcely know a drought when we see one. We welcome the first clear day after a rainy spell. Rainless days continue for a time and we are pleased to have a long spell of such fine weather. Dry weather continues and we become a little worried. Only when the dry spell stretches into weeks and months do we realize we are in trouble.

The first rainless day in a spell of fair weather contributes as much to a drought as the last, but no one knows how serious it will be until the last dry day is gone and the rains have come again.

In that sense, drought is a retrospective phenomenon. We cannot recognize that we are experiencing it until well after it has begun, and we cannot identify its end until after normal precipitation patterns have returned.

Drought is the deficit that results when the amount of water available in the soil is not sufficient to meet the demands of evaporation and plant usage for an extended period of time and over a large area.

What causes drought? Meteorologists and climatologists do not have satisfactory answers. Until the massive and costly drought of 1988, most textbooks on weather and climate mentioned drought only briefly. However, the economic impact of the 1988 event was so great that its effects were not forgotten, and serious inquiry into the causes of drought began.

Research continues, but answers are still not at hand.

The occurrence of drought seems to violate all the rules. Drought violates the law of averages in that it is a major and persistent departure from average precipitation. Drought seems to violate the theory of probability because consecutive weeks and months of far sub-normal precipitation is extremely unlikely in otherwise well-watered regions.

We cannot even explain drought in terms of climatic change because the rains always return -- eventually. The evidence is that drought has always been only a temporary condition.

Many definitions of drought are possible, and many schemes exist for classifying drought. Here's a classification that fits well for the United States:

Permanent drought: This is drought associated with arid climates. Adequate moisture is permanently lacking and vegetation is sparse. Permanent drought is a feature of the southwestern deserts of the United States and much of the intermountain west.

Seasonal drought: This occurs in climates with distinct, well-defined rainy and dry seasons. Vegetation, adapted to that climate, grows during the rainy season and becomes dormant during the drought period. Coastal California experiences seasonal drought -- its winters are wet and its summers are rainless.

Contingent drought: This is drought that results from the occasional failure of precipitation in areas that are otherwise well-watered. It occurs because, over time, rainfall is irregular and variable everywhere, even in moist climates. It is the kind of drought that Chicago and most of the United States experience, though rarely.

Richard Koeneman WGN-TV/Chicago Tribune Meteorologist

Never in 135 years of weather observations has the period from May 20 through July 6 seen less rain in Chicago. The past 47 days—a period over which 5.72” has fallen (on average) since 1871—hasn’t even managed an inch of rain. The 0.97” on the books is just 17% of the long term average and the least rain to fall in that period since records began.
It’s little wonder the percent of the Illinois corn crop categorized as “poor” or “very poor” rose in just a week’s time from 28% to 37% according to the latest USDA report. (A year ago, only 4% of the state’s corn was listed in similar condition.)
Tropical Storm Cindy crashed into the Louisiana coast overnight near Grand Isle. The storm’s 70 m.p.h. sustained were near hurricane force (74+ m.p.h.) at the point of landfall. Gusts clocked at the 150 ft. level of an offshore oil rig Tuesday afternoon reached 99 m.p.h.

Viewer Charlie Mellos from Arlington Heights was kind enough to send in these tree damage pictures from Monday afternoon's severe thunderstorm.

Photo by Charlie Mellos

Photo by Charlie Mellos

WELCOME RAIN COMES AT A PRICE

A severe thunderstorm struck the Arlington Heights area just before 1:30 p.m. on a warm and humid 4th of July afternoon. The quick hitting storm brought substantial rainfall to the area with .83" falling in a short period of time. Monday's rain was more than the .61" that fell here in the entire month of June in this parched area hard hit by this year's drought.

Though the rain will help plants in the short-term, the long term moisture outlook remains dim, with dry weather expected the rest of the week and the specter of more 90º-plus heat looming for the weekend.

The severe thunderstorm was accompanied by wind gusts estimated at between 50 and 65 m.p.h. Minor tree damage was scattered throughout the area, but some substantial tree damage occurred in the Scarsdale section of Arlington Heights.

4th of July tree damage in Arlington Heights

More damage from Monday afternoon's storm

Until brief thundery downpours hit Monday afternoon, north suburban Lake Villa—40 miles north of Chicago’s Loop—hadn’t recorded measurable rain for 28 days. The rain there accompanied a fast-moving cluster of thunderstorms responsible for 70 m.p.h. winds in DeKalb, lightning which flattened a tree in nearby Sycamore and tree-limb downing gusts from northern Kane County east to Wheeling and Libertyville. But, the corridor of half inch or greater rainfall was narrow—generally only 10-15 miles wide. The downpours within it forced drivers off roads and highways briefly in southern Lake County. But, when all was said and done, soaking rains evaded most of the Chicago metro area. Midway Airport recorded just 0.05”, and the official 0.10” at O’Hare barely nudged the area’s growing season rain tally (the rain since March 1) higher—to 5.85”. The total is less than the 6.47” tallied over the same period in the infamous 1988 drought.

The Chicago area appears to have a decent shot at getting some much needed rain today, but other than disrupting holiday festivities, the rain should have little effect in improving the area’s severe drought status. Today’s rain threat appears to be the only one this week, as high pressure builds into the Midwest following this afternoon’s cold frontal passage. With plenty of sunshine and low humidity midweek, followed by more 90s by next weekend, the area’s drought conditions are likely to hold steady at best, but probably worsen.
In contrast, substantial rainfall is expected to fall across Mexico’s Yucatan peninsula today as a tropical depression moves across that region. Hurricane forecasters are concerned that the system will strengthen into Tropical Storm Cindy as it crosses the Yucatan and moves into the warm waters of the Gulf of Mexico on Tuesday.

After a two day respite from recent hot weather, area temperatures will be on the rise once again as southerly winds send another surge of heat toward the city. Highs should top out in the upper 80s today and reach the lower 90s on Independence Day. Northeast winds will provide another refreshing heat break midweek, but more 90s are on tap by next weekend.
Despite the frontal passages associated with the advancing and retreating hot weather, prospects for a wide coverage, significant rainfall here remain slim; not a favorable scenario for an area locked in severe drought. And even though Nature may provide some thundery fireworks Sunday night and Monday, most of the remaining holiday period should be dry.
In contrast, violent thunderstorms packing heavy rain and 80 m.p.h. winds swept across portions of east Texas and Louisiana Saturday downing trees and power lines and damaging numerous homes.

The Independence Day weekend is off to a spectacular start. Sunshine and unlimited visibilities return for a second day. Friday’s highs held in the 70s for the first time in nearly two weeks—readings 20 degrees below the steamy 90° levels of the past week. But, the transition to beautiful weather occurred with comparatively low coverage rainfall. Midwest lawns and farm fields still languish after four months of drought.
The pattern couldn’t be more different in the Southeast. Waves of rain have swept the area with great regularity since spring, sending the region’s rainfall totals soaring. Sections of Florida have been especially hard hit. Naples was swamped in June by a record 21.28” of rain, more than 2.5 times the normal 8.18”, and 60 percent of Chicago’s annual rainfall.
Powerful storms prompted weather watches in the Plains. A twister touched down in North Dakota, and another was reported in Canada’s Manitoba Province.