May 2006 Archives

Powerful thunderstorms erupted in downstate Indiana and Illinois Wednesday unleashing half a dozen twisters—five of which touched down in the area surrounding Monticello, Indiana. It's fortunate most of these touchdowns occurred in fields, reports WGN-TV weather observer Mary Anne Best of Remington, Indiana, because they did little damage. Our thanks to Mary Anne for forwarding these pictures to us of one twister—the photos provided to Mary Ann by Mike Prangley, Chief Meteorologist at WLVI in West Lafayette, IN. Mary Anne notes that Monticello was one of the communities severely damaged in the infamous "Super Outbreak" of 1974--the country's biggest single outbreak of tornadoes.
- Tom Skilling

The same front responsible for Chicago’s temperature downturn Wednesday produced powerful thunderstorms downstate, including a half dozen tornadoes and thundery downpours which flooded fields. Initial reports indicate four twisters touched down around 2:40 p.m. Wednesday afternoon near Monticello, Indiana, 100 miles southeast of Chicago. Two other tornadoes occurred in central Illinois—one in Champaign County and the other south in Douglas County. Spotters monitoring the storms indicated no damage, saying the twisters’ paths remained away from most structures, traveling the area’s open fields.
Dust thrown into the air by the tornadic winds lent the storms a dramatic appearance. Torrential rainfall, including 5.50” in less than 2 hours near Pesotum, Illinois—15 miles south of Champaign—produced pools of standing water 2 feet deep.
-Tom Skilling

Powerful thunderstorms erupted in downstate Indiana and Illinois Wednesday unleashing half a dozen twisters—five of which touched down in the area surrounding Monticello, Indiana. It's fortunate most of the touchdowns occurred in fields, reports WGN-TV weather observer Mary Anne Best of Remington, Indiana who forwarded these pictures of one twister taken by a friend. Mary Anne notes that Monticello was one of the communities severely damaged in the infamous "Super Outbreak" of 1974—the country's biggest single outbreak of tornadoes.
-Tom Skilling

The powerful thunderstorms which swept sections of the Chicago area
Tuesday are captured blowing into the heart of the city in these images
relayed to us by Nick Liveris.
-Tom Skilling

A barrage of cloud-to-ground lightning strokes accompanied clusters of downpour-generating thunderstorms Tuesday. At the storms’ peak in the late afternoon and evening, AM radio broadcasts included a nearly continuous chorus of thunderstorm sferics—the unmistakeable crackling which pours from radio receivers as lightning occurs. The generation of lightning produces electromagnetic pulses responsible for the radio crackles. Cloud-to-ground lightning from all the thunderstorms within a 150 mile radius of Chicago was measured at a rate of more than 900 strokes every ten minutes late Tuesday afternoon and evening. The day’s heat and humidity produced t-storms—some 52,000 ft. high. Thundery downpours swamped localized areas with as much as 1-2” of rain, covering some roads in McHenry, Lake and Grundy counties—among others—with as much as 4-6” of water.
-Tom Skilling

Monday's powerful Memorial Day storms were captured as they bore down on the west suburban Naperville area in these shots from Scott Sanborn. The storms generated 1" diameter hail near Elgin and produced rainfalls approaching 0.80" in under an hour's time near St. Charles and Arlington Heights. Kankakee County was drenched by rains estimated by Doppler Radar at a few locations to have topped 4" Monday.

Monday’s muggy, moisture-saturated atmosphere destabilized explosively as temperatures surged. Destabilization is the term applied by meteorologists when temperatures decline more rapidly than usual with height. It encourages air to ascend vigorously, a process which on Monday converted the 1.5”-2” of water which permeated the lower 3.5 miles of the steamy Memorial Day atmosphere in vapor form into banks of towering thunderstorms—some up to altitudes of 55,000 feet. At that height (though it was hot at ground level) readings dropped below -80° F. Much of the day’s t-storm clouds were below freezing, fostering the growth of huge hailstones—some as large as 1”—which crashed to Earth in driving downpours and wind gusts to 75 m.p.h. like those in Crete, Ill., and Schererville, Ind.
Kankakee County was the epicenter of the area’s heaviest rain. Doppler radar estimates topped 4” in parts of the county. Water stood 2-3 feet deep in Bourbonnais.
--Tom Skilling, WGN-TV Meteorologist

Memorial Day for Chicago will start out sunny and mild, but humidity is expected to rise as clouds increase during the day. Temperatures should reach well into the 80s, perhaps reaching the 90° level—some 15 degrees above the normal (75°) for this date. Showers and thunderstorms in southern and central Illinois will be pushing north, possibly reaching the metro area later this afternoon. Yesterday was hot with the 94° at Midway Airport establishing a new record high for May 28 at that site, while the 92° at O’Hare just missed the old record by a single degree. Humidity remained just low enough to hold area heat index values in the middle 90s.
However, dermatologist Dr. Bryan Schultz, who provides sunburn times for the weather page, indicated Sunday’s almost unlimited sunshine resulted in the highest ultraviolet radiation readings to date in 2006.
Record highs were set Sunday in at least six states from the Plains to the western Great Lakes.
--By Paul Dailey, WGN-TV Weather Center Meteorologist

With the upper jet stream flow pattern favoring the advance of warm humid air from the south and west into northern Illinois, temperatures are expected to climb through the 80s into the 90s today. The air mass will carry dew points in the lower 70s which when combined with the season’s first official 90° high could result in a triple-digit heat index. A pocket of unstable air prompted a severe thunderstorm watch just to Chicago’s west and north yesterday and produced scattered t-storms a few of which brought damaging winds and 3/4-inch hail. Weakened storms passed through Chicago, and the weather system is moving east into Lower Michigan today.
An upper air pattern shift is forecast mid-week with a cold front expected to produce a period of potentially severe t-storms and heavy rains. Subsequent northerly flow out of Canada will usher in significantly cooler and less humid air to NE Illinois the latter half of this week.
-Paul Dailey, WGN-TV Meteorologist

Friday’s 83°, the warmest of 2006 and the highest temperature logged here since Oct. 5, is just the beginning if cloud cover and winds behave as predicted. The Chicago area and much of the Midwest is headed for the region’s first string of 90° highs Sunday through Tuesday. The heat is expected to arrive in the midst of the most humid weather in nine months. Dew points, the preferred measure of atmospheric moisture by meteorologists, are to hit the low 70s Sunday afternoon. That implies a level of mugginess not unlike that found regularly on this nation’s Gulf Coast and in the tropics.
The incoming round of summerlike weather, tempered in lakeshore areas Saturday by southeast winds off still-chilly lake waters, will put the Memorial Day holiday on track to become the warmest weekend of the past 37 weeks overall. Not since Sept. 10-11 has a weekend produced higher temperatures in Chicago.
—By Tom Skilling, WGN-TV Meteorologist

It may feel more like the 4th of July instead of Memorial day in Chicago this weekend, as the city prepares for the arrival of the season’s first 90º days and muggy 70º dew points. Lingering clouds and light showers should depart later today setting the stage for weekend sunshine that will send the mercury soaring.
Chicago’s heat will arrive in force Sunday as winds lose their lake trajectory, blowing in from the southern Plains, where numerous record highs were established Thursday, including 92º at Joplin, Missouri and 96º at both Tulsa and Oklahoma City.
The severe thunderstorms that raked Chicago late Wednesday moved east to blast areas from Michigan to Kentucky on Thursday, with nearly 220 reports of severe weather. After reviewing damage from Wednesday evening’s storms, the National Weather Service determined that an F1 tornado struck southeast of Kankakee near Aroma Park.
-Steve Kahn, WGNTV Meteorologist

Thunderstorms hit the area in a series of powerful waves Wednesday, prompting severe weather watches and warnings and targeting a multi-county east/west corridor to Chicago’s south for the meanest meteorological assault. The wild weather followed Chicago’s first official May 80°. By late evening, sections of Iroquois, Kankakee, and Livingston counties—east into Indiana’s Jasper and Newton counties had suffered storm damage ranging from downed trees to snapped utility poles. Thundery downpours swamped sections of Kankakee County stranding cars in high water. 2.60” fell at Bonfield while 2.80” was reported just northwest.
The strongest of Wednesday’s storms towered into the stratosphere—an atmospheric layer through which temperatures warm with height rather than cool—a situation which checks the vertical cloud development of all but the most powerful storms.
-Tom Skilling

Strong, potentially severe thunderstorms threaten to erupt in parts of the Chicago area later Wednesday. The storm threat is to follow only the third 80° high to date this year—the first daytime reading to surge above 80° in the nearly five weeks since April 14 when an 81° high occurred.
Humid air and the rich supply of stored energy it delivers in the form of latent heat, may interact with strong jet stream winds to produce clusters of rotating supercell thunderstorms capable of generating high winds, hail and even a few twisters in sections of the Midwest later today. Additional thunderstorms could fire Thursday as a pool of cold air positions itself above the warm, moderately humid air predicted here. A comparable set-up produced 10-mile high t-storms in the Plains late Tuesday, including one which blasted Hastings, Neb. with 81 m.p.h. gusts.
-Tom Skilling

Big weather changes, including the city’s first 80° high in 5 weeks are getting underway. Temperatures surge back into the 70s Tuesday afternoon with the first 80° of May due Wednesday. But, warming really gathers steam this weekend, offering Chicago its first shot at a 90° Memorial Day high for the first time in the 12 years since 1994.
Monday’s cloud-free skies produced only the second day this month with 100% of its possible sunshine, but the sun’s rays were unable to overcome lake cooling. Monday was the 12th straight day to produce a temperature deficit. The period’s average 61.1° daily high is the 2nd lowest May 11-22 on the books since the start of weather observations at O’Hare in 1959.
The story in the Plains couldn’t have been more different. Temperatures sizzled with new records at Chadron (93°), Alliance (92°) and Imperial (94°)—all in Nebraska.
-Tom Skilling

It turned chilly in Chicago Sunday as brisk northeast winds blowing down the entire length of Lake Michigan allowed highs to only reach the lower 50s near the lake and the lower 60s inland—a sharp decline from Saturday’s mild 70s. The chill was prevalent throughout the Great Lakes region with late-season snow falling at Marquette, Mich., Sunday and frost or freeze conditions expected Monday morning across a broad area from Minnesota to Ohio.
However, a change is under way as a northward shift in the jet stream will allow summer-strength heat that has been building for weeks over the South and West to shift north into Chicago later this week. The city should record this month’s first 80º day by Wednesday and possibly the season’s first 90º by the upcoming Memorial Day weekend.
Today marks the 151st anniversary of Chicago’s earliest recorded tornado that killed three and injured six in the Norwood Park area on May 22, 1855.
--By Steve Kahn, WGN-TV Weather Center Meteorologist

Chicago has been mired in a cool and showery funk this May, devoid of any hint of warmth from the fast approaching summer season. With two-thirds of the month already gone, the highest May temperature on the books here has been a paltry 74º, and the city has been peppered with measurable showers on 11 days. All that is about to change, as a dome of heat that has been setting records across the West and South appears ready to make a move toward the Midwest.
Saturday afternoon highs reached the 90s across the nation’s southern tier with triple digit heat common in the Desert Southwest and western Texas. Record highs were established at Lubbock (101°), San Angelo (102°) and Midland (103°), all in Texas.
The heat here will arrive in stages. After today’s brief cool down, highs should stair-step through the 70s and 80s, possibly reaching the 90º mark for the first time this year, just in time for the Memorial Day weekend.
-Steve Kahn WGN-TV Meteorologist

Temperatures surge back into the 70s Saturday afternoon and may become May 2006’s highest to date if a bit of compressional warming—the heating which results as air sinks and compresses—materializes as predicted. Low 70s are assured with or without any enhanced warming. But, with the Chicago area predicted to sit beneath a pocket of especially strong jet stream winds (the jet streak), a region where air sinks and warms on a large scale, a 75° high appears within reach later Saturday. It’s a reading one degree warmer than May’s previous warmest temperature of 74° back on the 10th.
The passage of a wind-shifting cold front, predicted to occur here between 8-10 p.m. Saturday, may generate several gusty thunderstorms and introduce cooler air for Sunday—especially near the lake with NNE winds locking in during the afternoon.
Heat to the west broke records Friday and produced 100° highs in parts of Kansas and Oklahoma.
--Tom Skilling, WGN-TV Meteorologist

This week certainly had its share of active weather moments—especially on Wednesday when storms raked the area. Here are a few pictures that highlight the events of the past few days:

Here's a close up of some hail stones—the dime shown gives you an idea of their size (photo courtesy of J. Crocker, Uptown-Chicago)

Here are a few snapshots of some heavy hail that fell in Norwood Park (photo courtesy of Thomas Nava)

Here's a look at the late-afternoon cumulus clouds near Algonquin on Wednesday (photo courtesy of Matt Hoelter of Cary, Ill.)

It’s been nearly 5 weeks since Chicagoans have enjoyed 80°. Since 1928, only 13 Mays have failed to produce at least one 80° in the month’s opening 19 days. Even more remarkable, May 2006—averaging 1.2° below normal—hasn’t even managed a 75° high. That hasn’t happened since 1948.
Small hail within several scattered thunderstorms pelted parts of the Chicago area for a second day Thursday. With cloud tops Thursday morning at 29,000 ft. and freezing temperatures just 5,000 ft. above the ground, the majority of Thursday’s shower clouds were below freezing—a situation which fostered hailstone development and growth.
Thursday’s 0.03” of rain marked the 9th consecutive day this month with measurable precipitation. Only three other Mays—including 1949 (with 11 straight days of measurable rain), 1945 and 2001—have hosted as many consecutive days with measurable rain.
-Tom Skilling

What started out as a beautiful Wednesday with sunny skies and temperatures reaching the lower 70s, took an abrupt downward spiral in the afternoon as waves of showers and thunderstorms spread into the area from the northwest. The storms turned severe with hail peppering much of the area, some of it as large as golf balls. Winds shifted to the north reaching speeds as high as 40 m.p.h. as the mercury plunged 20º into the lower 50s erasing all memories of the delightful morning. The Chicago area was not alone in Wednesday’s storminess with hail and strong winds reported throughout the Great Lakes region.
The weather will continue on the cool side into this weekend, but longer-range computer forecasts hint at a substantial warm-up by the first of next week with readings headed for the 80s, uncharted territory for Chicago temperatures so far this May.
-Steve Kahn, WGN-TV Meteorologist

Chicago’s temperatures pop into the lower 70s today, the first time that has happened since the city logged a 74° reading one week ago.
Normally, we would expect four 70° days in that period. And should measurable rain (that is, at least 0.01”) fall today, it will be the eighth consecutive day of rainfall. Total rain in those days has been 1.30”.
Let’s put that into perspective: 10.45” has drenched Boston in a comparable period—eight times as much water as has fallen on Chicago.
After today’s 73° reading (only slightly above the day’s normal high of 70º), cooler air locks in yet again and temperatures are forecast to run below normal through the weekend.
By next Monday, however, computer models indicate a major weather pattern change that suggests readings well into the 80s.
-Richard Koeneman, WGN-TV Meteorologist

Chicago’s string of sub-normal days extends to six with today’s reading in the lower 60s, but cool air will briefly relax its grip on the city Wednesday with temperatures expected to top 70º.
Elsewhere, national weather has taken some harsh turns. The same storm system responsible for Chicago’s cool temperatures has simultaneously delivered a multi-day deluge of rain to New England. Rainfall records have toppled in Massachusetts, hardest hit of that region’s states.
At only 15 days into the month, Salisbury, Mass., has logged 18.82 inches of rain, blowing away the state’s previous full-month May record of 15.60”.
The opposite end of the nation, meanwhile, is simmering in unprecedented early-season heat. Some Oregon records established on Monday: Portland, 95º (old record 81º); Astoria, 90º (76º); Medford, 96º (92º). Stockton, Calif., 97º (89º).

Sometimes the atmosphere settles into a rut, and this is one of those times. In terms of the weather, it’s as if the U.S. is two completely different countries. Chilly temperatures, widespread cloudiness and rain prevail from the Midwest to New England, whereas it’s hot and dry across the West.
The big story is serious flooding in the Northeast. Record rainfall and resultant river flooding have swamped portions of New England. Boston established two consecutive rainfall records with 3.84” on Saturday and 3.36” through 7 p.m. Sunday, with rain continuing.
Chicago’s scattered showers and sub-normal temperatures through Tuesday are inconsequential by comparison.
It’s all due to a large and stubbornly slow-moving storm system—meteorologists call it a “closed upper low”—that will not relax its influence on Midwestern and Eastern weather until Thursday.
-Richard Koeneman-WGN-TV Meteorologist

The last Mother’s Day with a high temperature in the 50s was just four years ago, and that fits Chicago’s climatology, which says in one out of every four years the second Sunday in May will have a high temperature in the 50s. Records also show that just as often on the second Sunday in May, highs warm into the 70s. The “average” high for Mother’s day is 66°, but there is a tremendous 50° range from a high of 39° observed in 1981 to an 89° recorded in 1986 and again in 1956. With a low pressure system stymied over the western Great Lakes the last four days forecast to continue to slowly drift east, Chicago’s string of days with high temperatures below 60° may well reach five before readings hit the mid 60s Tuesday. 70° is possible Wednesday before a change back to cooler conditions the remainder of this week. Latest computer models hint at development of a band of heavy rain early the following week, centering on NE Illinois May 23.

It may be Wednesday before the Chicago area is treated to anything resembling normal late-May temperatures. If the passage of a southbound cold front holds off until Wednesday night, the day may well host the first 70° reading in a week. Until then, the region remains mired in an unseasonably chilly weather regime. By Monday, it will have produced five straight days here with readings in the 50s or lower.
O’Hare’s 47° high Friday fell 3 degrees shy of the official site’s coolest on record for the date (44° in 1882). However, it was a different story at Midway Airport where Friday’s 45° peak reading was one for the books—a record breaker that eclipsed the 46° high back in 1966. Never has a May 12 been any colder since records began there in 1928.
The Chicago area wasn’t alone in setting records. Among other record low daytime highs Friday were 44° at LaCrosse, Wis., and 43° at South Bend, Ind.
--Tom Skilling, WGN-TV Meteorologist

A 124 year old record for the chilliest daytime May 14 high—44° set in 1882—appears vulnerable Friday. The thick overcast predicted to linger through much of the coming weekend promises to eliminate sunshine capable of boosting readings during the day. As a result, temperature levels rise no higher than the 40s Friday—levels more typical of early March and 24° below normal. Another half inch of rainfall is predicted by Saturday bringing this storm’s total to 1.50” at many locations.
NW winds, though hardly as strong as those which whipped the area yesterday with gusts to 44 m.p.h. at O’Hare and 48 m.p.h. at DeKalb, have forced chilly air into the metro area. By late Thursday, light snow was reported as far south as Madison, Wisc. Though light rain is predicted here at times Friday, several ice pellets or flurries can’t be ruled out in a few sections of the Chicago area—especially Friday morning.
-Tom Skilling

It’s rained measurably during May a total of 1,060 times since weather records began here in 1871. But, in only 42 May storms during that period has rainfall reached or exceeded 1.80”. With a consensus of 14 computer model projections putting this storm’s rain near 1.84” by Friday’s close, it appears a 43rd is on the way. It’s rained comparably hard (or harder) only 375 times in 135 years, suggesting totals of that magnitude can be expected to occur an average of three times annually. The last time this much rain fell here was the 1.80” logged August 27-28, 2004.
The storm responsible for Thursday’s wind-driven downpours has intensified rapidly over the eastern Midwest overnight. Central air pressures have plummeted a stunning 20 mb—the equivalent of 0.60” of an inch of mercury. Barometer observers will appreciate such a drop—a change which is converting the system into a giant wind machine.
-Tom Skilling

Wednesday’s comparatively tranquil daytime weather--including an 18th daytime temperature at or above 70° this year--belies a series of important meteorological changes which are on the way. The Chicago area appears poised to experience its most prolonged spell of consecutive 50s beyond May 10 since five occurred back to back between May 17-21 in 2002. Weather records reveal strings of three of more 50s occur here this time of year an average of one May in five. The longest such string occurred in 1917, a period in which the city’s official weather observations were taken closer to the lake than today. A spell of 13 consecutive 40 and 50° days was logged that year between May 1-13.
A powerful storm initiates the Chicago area’s transition to markedly cooler temperatures beginning in Thursday’s pre-dawn hours. By Thursday afternoon, readings will have plunged more than 20°.
-Tom Skilling

Not since 2001 have the opening nine days of May been milder across the Chicago area. Tuesday’s predicted 73° high marks the 17th time in 2006 a daytime high has surged past 70°—nearly 1.5 times the long-term average by this date since 1871. May, 2006’s average of 57.1° exceeds the area’s 135 year long-term average by 2.1°.
The temperature downturn predicted to begin Thursday threatens to produce an extended series of daytime 50s. The average date of the Chicago area’s last three-day string of 50s has been May 1-3 at the city’s South Side Midway Airport observation site—making the predicted cool spell later this week fairly impressive by historical standards. Any sunshine through breaks in the clouds could produce localized heating, forcing temperatures out of the 50s. The city’s latest three-day string of 50s occurred June 4, 5 and 6, 1928 when readings peaked at 59, 54 and 58°.
-Tom Skilling

Chicago skies were cloudless Sunday as the city experienced a nearly perfect day with highs in the lower 70s. It marked only the fifth time in more than a month that the city recorded a day with 100 percent of possible sunshine. Temperatures will remain mild through Wednesday, though sunshine will fade as clouds increase, leading to a period of showers and thunderstorms Tuesday and Wednesday. Beyond that, the mercury will plunge as a low pressure system anchors itself over the upper Midwest, funneling cloudy and chilly air into the area.
While the Chicago area has emerged from drought, Florida is rapidly drying out. Orlando has recorded less than 4” of rain so far this year, the driest January-April period on record. More than 2,200 wildfires have occurred in Florida this year. Meanwhile, torrential rainfall has returned to Hawaii. Since Friday, Hilo has recorded nearly a foot of rain—more than the 11.24” Chicago has received in all of 2006.
-- Steve Kahn, WGN Weather Center Meteorologist

Temperature wise, the upcoming week will start off in a delightful spring mode with the potential for four straight days of inland highs of 70º or higher, though onshore breezes will restrict readings in areas near the lake to the 60s at least for today and Monday. However, the mildness will not last as a midweek cold front passage will shift winds into the northwest marking the start of a sharp cool down that should drop afternoon highs by nearly 20º by Friday.
The transition to cooler weather will begin with a period or two of showers and thunderstorms that should arrive by Tuesday evening. Beyond that, precipitation should be light and scattered, limited to a few showers or sprinkles the rest of the week—days that are expected to be cloudy, blustery and cool.
On a more positive note, the long distance look ahead to Mother’s Day weekend gives hope for sunny days with temperatures rebounding at least into the 60s.
-Steve Kahn, WGNTV Meteorologist

A bit of late-season frost greets early risers in some northwest suburban locations Saturday—but not for long. Sunshine returns with gusto and wastes little time going to work on the cool air mass in place at daybreak. With just 31 percent of this area’s possible sun reported over the past week, this weekend’s generous allotment will be welcome.
Chilly air tightened its grip on the Chicago area Friday, delivering the coolest afternoon readings here in 10 days. Temperatures, which peaked at 58° at 2:06 p.m., had pulled back to the low 50s by the evening rush hour. The 6 degree slide occurred as north winds took on enough of an easterly component to slice ashore off Lake Michigan’s cool waters. May 5 has produced cooler readings than Friday’s 58° only three times since 1970—the coolest among them being 43° in 1978.
Thunderstorms pounded west Texas Friday, producing eight twisters and 4.2”-diameter hail (grapefruit size) near Seminole.
--Tom Skilling, WGN-TV Meteorologist

The Chicago area’s most impressive early May stretch of mild days in six years yields to the chilliest air mass in 10 days Friday. The temperature downturn is temporary and comes on the heels of four consecutive above normal days—the most in early May here since 2000. A 4,000+ mile long band of north/northeast winds, extending from northern Greenland south to Texas, is a major factor in delivering Friday’s late season chill.
Sun-obscuring clouds and a wind trajectory off Lake Michigan preserve the lower temperatures by inhibiting warming. That there’s an easterly component to the wind is little surprise. Some form of easterly wind blows here 53% of the time in May, more than in any other month of the year.
The cool air’s arrival Thursday in the Deep South contributed to violent thunderstorms. Hail 4.25” in diameter pounded Mertzon and Baird—both in Texas.
-Tom Skilling

The Chicago area’s third 80° high of the year turned out to be elusive Wednesday thanks to thunderstorms which flared to the west and dissipated before reaching the city. But before that happened, their towering clouds, dubbed cumulonimbus by meteorologists, managed to mix cold air from the upper reaches of the storms down to earth’s surface producing what amounted to a natural air-conditioning effect. Wednesday’s surge in temperatures—which had reached 76° at Northerly Island by midday—halted when the storms’ rain-cooled outflow and leftover debris clouds cut into the supply of warming sunlight.
Even so, readings officially peaked at 73° at both O’Hare and Midway, marking the 14th time this year the mercury’s exceeded 70°. Nine such occurrences have been the average here since 1871—and only 11 had occurred by this time a year ago.

The 80° high predicted Wednesday brings to three the number of 80s on the books here in 2006. Only 12 of the 36 years since 1970 have logged as many or more 80s by May 3. The month is running 20° warmer than a year ago and is likely to add to the surplus this afternoon into Thursday before a sharp, two-day temperature downturn hits Friday and Saturday.
But, it’s on the precipitation front where truly significant differences appear over a year ago. Rainfall since March 1 at the area’s National Weather Service COOP observer stations is running two to three times—or even more—the levels recorded a year ago as the area plunged into a drought it’s been unable to shake until recent months. Measurable precipitation fell for the 30th time this meteorological spring Tuesday, far ahead of last springs 18 and the most here in 13 years (since 1993) when 33 days of measurable rain had occurred by this date.
-Tom Skilling

Recent rains are having an impact on the moisture shortage so much a part of the region’s weather for more than a year. The drought threat hasn’t been eliminated. But, the area finds itself in much better shape than at the same point in the meteorological spring season a year ago.
April’s 3.60”—the 49th wettest of the past 135 years—was the heaviest monthly precipitation tally here in 15 months. Not since the 4.00” which fell in January, 2005 has a single month hosted more rain.
The beneficial moisture wasn’t limited to the Chicago area. Illinois state climatologist Dr. Jim Angel reports statewide precipitation amounted to 4.60” in March and 4.08” in April—well above the 1.65” and 2.59” recorded a year ago.
A tornado touched down Monday evening within a mile of Williamsfield in west-central Illinois, 20 miles east-southeast of Galesburg.
-Tom Skillling