Severe thunderstorms still a possibility tonight across the Chicago area – strong winds tomorrow

A center of intensifying low pressure will move northeast out of Missouri through northern Illinois tonight. The associated warm front will be carried north with both the low center and warm front approaching and moving through the Chicago area after midnight – during the pre-dawn hours Friday.

With warm moisture-laden low level southerly flow streaming up the Mississippi River Valley into Illinois and a 100 mile-per-hour jet stream aloft, conditions are ripe for severe thunderstorm development to our south with the possibility that clusters of strong potentially severe storms with large hail, and damaging winds could erupt across the Chicago area as well later tonight.

Heavy 1 to 2-inch rains occurred across the southern portion of the Chicago area this morning and another round of more widespread thunderstorm downpours is likely overnight. Local flooding in already primed areas may be an ongoing problem into Friday morning.

Friday with the center of low pressure to our east, winds will shift to the southwest, and high pressure building in behind the departing low pressure will tighten the pressure gradient, resulting in very strong winds gusting between 40 and 50 miles per hour. Winds will become more westerly later in the day. High profile vehicles/trucks traveling on north-south highways will be especially susceptible, and affected drivers should be prepared to fight these turbulent winds tomorrow.

Heaviest 1 to 2-inch rains mainly south of Interstate-80 this morning

It was still raining at many observation points when the 8AM CDT reports came in this morning, but it was evident early that significant rainfall between 1 and 2-inches fell over much of the area south of Interstate-80 early this morning. Rainfall amounts tailed off significantly to the north with generally less than a tenth of an inch a short distance north of north of Interstate-90. Northernmost counties received little or no rainfall.

Following are some of the greater rainfall amounts reported at 8AM CDT…

Location             Rainfall (inches)

Marseilles                    1.50

Ottawa                         1.49

Aurora                         1.20

Pontiac                        1.73

Kankakee                    1.49

Morris                          1.09

Homewood                 1.07

Gibson                         1.83

Manteno                      1.00

Bonfield                       1.15

Seneca                        1.15

Streator                       1.14

Momence                    1.83

Oak lawn                     1.15

Chenoa                       2.14

Chatsworth                  1.05

Plainfield                     1.50

Joliet                            1.49

LaSalle                        1.36

Peru                            1.25

North Utica                  1.43

Oglesby                       1.13

Minooka                      1.07

Buckley                       1.98

Sheridan                      1.52

Mendota                      1.07

Homer Glen                1.04

Bradley                        1.97

Lisbon                          1.56

Sublette                       1.01

Naperville                    1.05

Coal City                     1.39

Manhattan                   1.18

Northwest Indiana

Chesterton                  1.80

Lake Village                1.80

Demotte                      1.50

Rensselaer                  1.00

Hobart                         1.13

Fair Oaks                    1.81

Wheatfield                   1.11

Hanna                         1.39

Mt. Ayr                         1.13

Munster                       1.40

Lakes of 4 Seasons    1.38

Valparaiso                   1.43

Hebron                        1.83

Risk of severe thunderstorms in Chicago area today and tonight

The National Storm Prediction Center has issued a severe storm outlook (see map below) that includes the southern half of the Chicago area in a slight risk (yellow-shaded area) of severe thunderstorms primarily later this afternoon and tonight. Southern Illinois is included in a moderate risk (red-shaded) area with the possibility of tornadoes that extends south including much of Arkansas and Missouri as well as portions of Kentucky, Tennessee, Mississippi and Louisiana.

Chicago will be located on the northern edge of the severe weather threat, with our best chance of severe thunderstorms with large hail and damaging winds occurring just south of Interstate-80. However as the storm system moves through northern Illinois tonight, the northern portion of the Chicago area could be at risk – mainly after midnight into the pre-dawn hours Friday.

An intensifying center of low pressure will track northeast out of Kansas through Missouri today, crossing northern Illinois into southeast Wisconsin into Lower Michigan later tonight. Strong low-level southerly flow will tap the Gulf of Mexico, pulling moisture-laden air up the Mississippi River Valley into Illinois as an upper-level impulse moves over the area. The associated warm front will lift north into central Illinois today – perhaps briefly reaching the Chicago area late tonight/early Friday morning. The center of low pressure system should be east of Chicago Friday morning with colder westerly flow over our area.

Map of Severe storm threat today and tonight

Mild windy afternoon ahead with chance of t-storms

As a cold front approaches from the west and temperatures warm into the 60s, winds will strengthen out of the south – gusting to 40 miles per hour this afternoon. A north-south oriented band of showers and thunderstorms is expected to develop over western Illinois early this afternoon – move east and pass through the Chicago area later this afternoon and early evening.

With the strong southerly winds, trucks and high-profile vehicles will be buffeted – complicating driving conditions – especially for those traveling along east-west highways. Wind funneling could cause drivers to encounter sudden wind bursts, so caution is advised.

The cold front is forecast to move east through our area later tonight followed by gusty winds out of the west and cooler temperatures Tuesday.

Thunderstorms possible here today/tonight – risk of severe storms just to our southwest

Showers and scattered thunderstorms will be possible across northern Illinois, southeast Wisconsin and northwest Indiana today and tonight. The National Storm Prediction Center has determined a slight risk of severe thunderstorms will exist over portions of western Illinois, as well as extreme southern Iowa, Missouri, Arkansas, Kansas, and Oklahoma (see yellow-shaded area on map below). The best chance of thunderstorms/severe storms in Illinois will be later this afternoon into the evening hours – the main risk in stronger Illinois storms being large hail and damaging winds.

A center of low pressure will move east-northeast out of the central plains today – tracking through northern Illinois and southern Wisconsin tonight. The associated cold front will sweep through the Chicago area around Midnight. Strong southerly winds gusting over 35 miles per hour will prevail ahead of the storm system .

 The first wave of showers and possibly a few thunderstorms will move through our area early this morning, then as the center of low pressure and cold front approaches and passes over the Mississippi River later this afternoon and evening, a stronger area of showers and thunderstorms is expected to develop over Illinois into Wisconsin.

Tim’s Weather World: Does a cold winter mean a cool spring and summer?

Elisabeth Benault

Elisabeth Benault

Will the spring and summer following a colder than average winter also tend to be cooler than average?   The winter of 2013-2014 was the 3rd coldest on record with an average temperature of 18.8°.   So far this spring has gotten off to a cool start.  18 of the first 25 days (72%) of this month have been below average.  March now ranks as the 18th coldest on record through the 25th of the month.  Does that mean our cold winter is spilling over into a cool spring and will that trend continue into summer?

The Chicago National Weather Service office crunched the numbers to see if there has been a correlation in the past.  They looked at the top 20 coldest winters on record and then the springs and summers that followed.

12 out of 20 springs that followed those coldest winters ended up being below average with seven of those springs ranking among the top 20 coldest springs on record.  So 60% of springs that followed colder than average winters ended up being cooler than average.

The bar graphs below show the departures from normal for the springs and summers that followed the top 20 coldest winters on record.

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The correlation is much stronger for a cooler than average summer following a colder than average winter.  80% of summers that followed the top 20 coldest winters ended up being cooler than average or 16 out 20 summers.

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Midway closes in on record snowfall

Only 2.9 inches of snow – that’s all Midway has to go to tie the all-time seasonal snowfall record of 89.7 inches set back in the 1978-79 season (Chicago snowfall observations go back to 1884). Midway picked up 0.9 inch overnight and O’Hare, our official observation site recorded 0.6 inch. O’Hare’s 2013-14 seasonal total now stands at 80.6 inches – third overall (we received 82.3 inches during the 1977-78 snow season.

The fast-moving cold front that triggered the band of snow last night has already moved into eastern Indiana, and cold Arctic high pressure is building into our area. The highest snowfall totals reported so far this morning were 1.0 inch at Downers Grove and Coal Valley.

Some area snowfall reports:

Location snowfall (Inches)
Downers Grove     1.0
Copal Valley          1.0
Midway                   0.9
Batavia                   0.8
Orland Hills            0.8
SE Chicago          0.7
O’Hare                   0.6
St. Charles            0.6
Bartlett                   0.6
Lockport               0.6
Geneva                 0.5
Palos Park           0.5
Elk Grove Village 0.5
Carol Stream       0.5
Bourbonnais        0.4
Elgin                     0.4
Dixon                    0.4
Beach Park         0.4
Roscoe                0.3
Inverness             0.3
Carbon Hill          0.3
Oak Park             0.2

Lake effect snow will taper and end as winds subside

Heavy lake effect snow squalls rolled into Cook and Lake (IN) counties shortly after 5AM Sunday morning dropping up to two inches of accumulation near the lakeshore.  Bursts of heavy snow occurred within 5 miles of the lake, resulting in very slick road conditions between 5AM and 7AM.  At 8AM, road conditions are gradually improving as the snow decreases in intensity and highway crews apply salt.

Ice coverage on the southern end of Lake Michigan has shrunk to 10% after peaking at 90% just two weeks ago.  Cold arctic air flowing over the open and relatively ice free lake water is responsible for today’s snow.

In sharp contrast to the clouds and snow downwind of the lake, most of Chicago’s north, northwest, west and southwest suburbs are waking up to sunshine this morning.

Here are a few snowfall reports from across the area:

1.5″ Chicago- Rogers Park

1.5″ Chicago- Loop

0.8″ Lincolnwood

0.7″ Chicago- Roscoe Village

0.5″ Hobart, IN

0.3″ Valparaiso, IN

0.2″ Chicago-Midway

0.2″ Porter, IN

0.1″ Gary, IN

BELOW:  Camera snapshots of some of Chicago’s snow covered streets and highways earlier this morning.

3.23 cam