City basks in warmest weekend since mid-November

It’s been a while since Chicagoans have been able to enjoy a mild weekend. This weekend’s highs of 51 and 57 were the city’s warmest since November 16-17 when the mercury peaked at 61 and 69. However, that weekend’s warmth was overshadowed by the major late-season tornado outbreak in portions of central and northeast Illinois that included the deadly EF-4 twister that devastated Washington.

Cloudy and chilly weather will return to the city Monday and Tuesday accompanied scattered showers and blustery northeast- north winds, but a burst of warmth delivered by gusty southwest winds will send the mercury soaring to near 70 degrees by Wednesday, a level of warmth not seen in the city in six month since mid-October.

More showers and are possible by next weekend as the next weather system approaches from the Plains.

April means greater tornado threat to Midwest

By Meteorologist Paul Merzlock

Climatologically, the month of April produces the area’s largest tornado events. Thursday marked the 40th anniversary of one of the nation’s most devastating tornado outbreaks. On April 3, 1974, at 1:10 p.m., a weak tornado touched down 10 miles north of Morris. It was the beginning of an 18-hour rampage that produced 148 tornadoes across 13 states. Thirty of those were particularly violent, EF4- and EF5-intensity twisters. By the morning of April 4, a total of 330 people had lost their lives, with over 6,000 injured. Damage totaled $4.5 billion in current U.S. dollars, and 10 states were declared federal disaster areas. From this tragic event, a silver lining emerged. Funding and research that followed produced the modern Doppler radar system now used by the National Weather Service.

Latest storm system spares the area its worst weather

Springtime weather across the Midwest can be notoriously fickle. The latest storm system to pass across the area was a good example. Temperatures in the low 40s, combined with wind gusts over 40 mph made for a less-than-pleasant April 4th. Highest winds were reported SW of the city, with Minooka registering a 55 mph gust. Though not the best baseball weather, conditions could have been much worse. The storm produced heavy snow across the upper Midwest, with 18” accumulations reported over northeast Minnesota and northern Wisconsin. To the south, flooding rains, damaging hail and tornadoes occurred from Missouri to Texas, and eastward through the Tennessee valley. Tranquil weather is forecast this weekend, with sunshine, light winds and seasonable temps expected.

Big rains move on leaving a classic high wind set-up in their wake; sprinkles may ride the day’s 50 mph gusts

By Meteorologist Tom Skilling

Powerful winds sweep the Chicago area Friday gusting to 40 and 50 mph at times. It’s a classic high wind set-up and it’s occurring as  strong winds wrap around the Wisconsin-based storm center.  Southwesterly winds Friday are literally stacked vertically tens of thousands of feet through the atmosphere, a set-up which rarely fails to generate the area’s strongest gusts.

Winds aren’t alone in wrapping around Friday’s latest spring storm. “Wrap-around” clouds are slated to shroud Chicago area skies well into Friday night before giving way to far sunnier skies over the coming weekend.

Cubs home opener more than 20-degree colder than a year ago—and windier too!

April’s finicky temperatures and weather are well known to Cubs fans. The team’s 1:20 p.m. opening pitch is to take place at Wrigley Field amid strong winds which will be effectively blowing from home plate out to center field. But a pullback in Friday temperatures, from a brief rendezvous with mid and upper 40s as the day gets underway, to the low 40s at game time means that Opening Day 2014 is to run 21-degrees chillier than last year’s 64-degree high.

Thursday’s 1.40” rainfall at Midway establishes a new record for April 3; heavier totals occurred south of  the city

The thundery downpours which hit early Friday ended up producing 1.40” of rain at Midway Airport but just 0.53” at O’Hare.

By comparison, it was the southern suburbs which chalked up the heaviest rain tallies. Hebron, Indiana was hit by 2.47”; Kankakee 2.28”, and 2.11” at Flossmoor.

Powerful spring storm—the 3rd in a week to impact the nation’s Heartland—delivering big snows to the North Woods, sporadically thundery downpours here and a severe weather outbreak south

By Meteorologist Tom Skilling 

A classic spring storm dominates the Midwest landscape, threatening quite a range in weather—-and over a huge swath of terrain.

A snowstorm is in progress across the northern Midwest while rain—some of it thundery —drenches the Chicago area. The precipitation is to hit in “waves”. As that occurs, an outbreak of potentially severe thunderstorms looms for areas downstate and in the southern and central Midwest.

Storm’s powerhouse backside winds to hit Friday for the Cubs home opener

The big rains expected to drench the Chicago area Thursday/Thurs. night will be followed by howling west to southwest winds Friday—the so-called “backwash” circulation. This could mean wind gusts as high as 50 mph  Friday as the Cubs take to Wrigley Field in their home opener.

Sunshine’s back for the weekend but a new storm could sweep into the Midwest early next week

Rains could top 1.50” in coming days–the Chicago area’s heaviest since late October

By Meteorologist Tom Skilling

Waves of rainfall associated with the third spring storm to sweep the Midwest and Chicago metro areas in under a week could generate the region’s biggest rain tally since  late October.

A suite of computer-generated rain forecasts is placing Chicago area rain tallies in the 0.98” to 2.42” range. That’s quite a rain!  An amount of more than 1.17 inches would exceed 2014’s highest tally to-date —the 1.16″ which fell on Feb. 20. It would become the heaviest total recorded here since 1.59” fell Oct. 30-31.

Heaviest rains to hit in two waves—the first overnight into Thursday morning; a 2nd Thursday night

The incoming storm system is to produce rainfall in a series of waves beginning Wednesday night.

The two heaviest periods of precipitation appear likely to occur Wednesday night into Thursday morning and again Thursday night.

The manner in which a storm system generates and distributes its precipitation is often extremely complex. Rainfall rarely falls homogeneously, occurring instead in bursts, the intensity of which can be dictated by features such as thunderstorms. Thundery downpours can concentrate heavy rainfall over the swaths of terrain they travel. These areas may receive considerably more moisture than surrounding areas.

Flood of warmth and moisture up and over chilly air here predicted to generate embedded thunderstorms

Thunderstorms are likely to occur with this developing weather system. The moisture fueling the storm is riding northward through 80-degree and warmer air within its southern flank.

Such warmth not only assures quite a supply of moisture, it also  “destabilizes” (i.e. increases the rate at which temperatures fall with height), encouraging air to rise, producing towering thunderstorm clouds within the storm system’s precipitation shield.

Storm threatens to spawn major severe weather outbreak from Plains to areas downstate next 2 days; wind-driven snowstorm to lambaste corridor from Iowa to Minnesota, western Wisconsin and Upper Michigan

Outbreaks of severe thunderstorms are predicted within this storm’s warm sector while howling (and cold) northeast winds to the north of the storm center are to produce significant snows through areas from north-central Iowa north across the Twin Cities and into Michigan’s U.P.

Wet pattern looms beyond Tuesday’s sunshine

By Meteorologist Tom Skilling

One huge spring storm—responsible for the powerful southerly winds Monday which sent temps soaring well into the 60s for the first time this year, is to be followed by another even wetter system the middle and end of this week.

The first system’s roaring front-side southerly winds produced a 68-degree peak reading here in Chicago–the highest temp which has occurred here in the 134 days  since last Nov. 17.

It brought Sox fans an opening day which was 27-degrees warmer than its predecessor in 2013.

But, the story was quite a different one for residents of the northern Plains. There, on the cold side of Monday’s sprawling, windy system, blizzard conditions, including wind gusts topping 60 mph and local 12”+ accumulations, rendered travel all but impossible.

Waves of rainfall-some thundery—may generate in coming days some of the biggest Chicago area rain totals in  in 5 months  

A second storm assembles over the Plains in the days to come. All indicators suggest this system will be wetter than to first. Its rains are likely to commence in Chicago  Wednesday afternoon and continue Wednesday night. A suite of computer rainfall projections generates an average rainfall of 1.20 inches.

Temps to peak Monday, before April showers arrive

High temperatures Sunday afternoon soared into the 60s and 70s from the central plains, eastward across the Mississippi valley. Similar warmth is expected Monday, even as a strong cold front settles into the upper Midwest. This scenario will establish a large temperature contrast, setting the stage for storm development. Deepening low pressure west of Chicago is then forecast to produce gusty south winds that will bring the city its warmest day in over 4 months. Unlike Sunday, which started with daybreak temps in the mid 20s, readings Monday morning will be much milder, making 60-degree temps likely in the afternoon. The flow of mild air will be short-lived. By Tuesday night, cold northeast winds are expected to develop, and continue the remainder of the work week.

Year’s first 60-degree weather to finally arrive

Chicagoans have endured a cold and snowy winter, and a transition to spring that has been anything but balmy.  Aside from 2014, only nine other years since 1928, have failed to record a 60-degree reading at Midway airport by March 29th. The average date for the first occurrence of a 60-degree temp is March 2nd.  On Sunday, temps are expected to approach 60 degrees. Increasing south to southwest winds will deliver mild air to the region. Highs on Saturday reached 60 degrees or higher as far north as the Dakotas. It will be even warmer Monday, as temps reach the mid and upper 60s, just in time for the White Sox home opener. Chilly, unsettled weather is to return as April arrives. The Cubs home opener on Friday looks chilly, with brief showers possible, and highs in the low 40s.

Northeast winds on north side of intensifying spring storm to produce a chilly start to the weekend

The easterly winds, which blow off Lake Michigan’s notoriously cold spring waters with irritating frequency, have few fans among the winter weary in and around Chicago. It’s obvious why. Their “warmth-extinguishing” nature is hardly what a population which has been shoveling snow for months wants to see.

Saturday’s gusty northeast winds offer a perfect, real-life example. An intensifying storm to Chicago’s south is combining forces with a sprawling Canadian high pressure to the north to produce gusty northeast winds likely to prevent temperatures from getting anywhere close to the normal high of 51-degrees.

Thankfully the easterly flow isn’t likely to last.

Warming temps likely to establish 2014 highs in coming days; daytime readings by Monday are likely to register a near 30-degree increase

The good news is that the vigorous warming, predicted to send temps to 60-degrees and higher for the first time this year Sunday and to 68-degrees Monday—appear on track.

The warm-up means Sox fans, who suffered through a 41-degree chill at last year’s home opener, may this year enjoy a temp within striking distance of 70-degrees.