Very dry, cool northeasterly flow held off the incoming rain Sunday for a good portion of the metro area. A solid area of rain continually pushed northeast and tried unsuccessfully much of the afternoon to cross U.S. Interstate 80 into the western and closer-in southern suburbs, evaporating as it fell into the much drier air.
By Sunday evening rainfall amounts south of I-80 were on the order of a tenth to a quarter inch, while north of the I-80 corridor just a trace was reported. Overnight the air to the north was expected to gradually become saturated, allowing rain to reach the ground over much of the metro area by Monday morning.
Clouds and rain expected the first half of Chicago's workweek
As low pressure strengthens and moves slowly northeast out of Missouri into Illinois, clouds and extended periods of rain are likely in Chicago through Wednesday. Best estimates are that heaviest rainfall, perhaps as much as a half to three-quarters of an inch, will likely occur later Tuesday into early Wednesday. A break in the clouds is forecast later in the workweek with a warm-up over the weekend.
WGN-TV Chief Meteorologist Tom Skilling and the WGN Weather Center staff provide daily coverage of weather in the Chicago area.
Recently in Dailey Category
Much of the work week looks to be on the cool side with periods of cloudiness as minor weather disturbances move through. The upper-air flow pattern becomes more northwesterly, steering cooler air into the Midwest and holding milder air well to the south of the Ohio River. The jet stream will shift north by Friday with a weaker westerly flow aloft over Illinois, allowing milder air to ride southerly surface winds into northeast Illinois. While showers will be in the forecast off and on this week, expected rainfall should be on the light side. Thus runoff into rivers and streams will be primarily from the saturated soils, allowing for at least a little drying as the week goes on. Temperatures in the 60s and gusty winds over the coming weekend will also help to dry the soils, but again be tempered somewhat by the possibility of scattered showers.
Flood advisories
Flood advisories remain up for many rivers in states bordering on the Mississippi River from Louisiana all the way north to Illinois and Iowa. Most rivers in northeast Illinois and northwest Indiana are running close to bankfull, but the flood threat is farther to the south, the nearest being at LaSalle on the Illinois River.
Flood advisories
Flood advisories remain up for many rivers in states bordering on the Mississippi River from Louisiana all the way north to Illinois and Iowa. Most rivers in northeast Illinois and northwest Indiana are running close to bankfull, but the flood threat is farther to the south, the nearest being at LaSalle on the Illinois River.
It's been a long time coming, but rain moved into northeast Illinois, southern Wisconsin and northwest Indiana Sunday afternoon, ending a dry period that started in late August. Rainfall totals by Sunday evening ranged from a quarter to a half inch over the metro area. Earlier on Sunday, heavy rains downstate caused flooding of creeks, streams and susceptible roadways. There were numerous reports of one and two inch rainfall, and several locations in central Illinois received well over three inches. Jacksonville, just west of Springfield, recorded 4.76 inches. More flooding and 3-inch-plus rains occurred along the Ohio River in northern Kentucky and southern Indiana. All this rain was actually the northern edge of the record rainfalls that have been occurring across the Gulf Coast states as well as Missouri, Arkansas and Tennessee.
Cloudiness and showers to dominate forecast into next weekend
A strong low pressure system to the lee of Rockies over the Central Plains is forecast to remain essentially stationary much of the week ahead, finally ejecting to the northeast next weekend. This will mean an almost continuous flow of warm, moist air north up the Mississippi Valley, occasionally reaching northern Illinois and resulting in extensive cloudiness and periods of showers/thunderstorms, rather high humidity, and mild temperatures for the Chicago area.
Cloudiness and showers to dominate forecast into next weekend
A strong low pressure system to the lee of Rockies over the Central Plains is forecast to remain essentially stationary much of the week ahead, finally ejecting to the northeast next weekend. This will mean an almost continuous flow of warm, moist air north up the Mississippi Valley, occasionally reaching northern Illinois and resulting in extensive cloudiness and periods of showers/thunderstorms, rather high humidity, and mild temperatures for the Chicago area.
It's been two weeks since September's only rainfall was recorded at O'Hare International Airport, Chicago's official observing site. It won't take much rain to exceed our entire monthly total of 0.03 inch. The high pressure regime that has produced an almost steady east wind along with the dry conditions and mild temperatures is finally breaking down. A low pressure system is set to establish itself over the Rockies and influence weather over the Midwest this week. A southerly flow up the Mississippi River Valley should feed warm, moisture-laden air into Illinois, resulting in considerable cloudiness. Even though showers or thunderstorms will probably not occur every day, it will be difficult for meteorologists to leave rain out of the daily forecasts.
Eastern U.S: A land of contrasts
The upper-air blocking pattern has persistently held the center of cold high pressure over the Northeast. Sunday morning frost and freeze advisories were posted for most New England states as well as northern lower Michigan. Meanwhile, persistent low pressure to the south has resulted in record heavy rains and flooding over the Gulf Coast the past week. Atlanta was among the latest, reporting a record daily rainfall of 3.7 inches Saturday.
The upper-air pattern remains relatively unchanged with the stronger northern jet stream winds well to the north in Canada and the southern jet running from the Gulf of Mexico up the eastern seaboard. The light winds aloft leave little opportunity for any significant air mass changes here in the Midwest or western Great Lakes. As a result, the light easterly flow continues to allow fine particulate concentration to slowly increase, and hazy conditions will persist. In Wisconsin the Department of Natural Resources has continued an Air Quality Watch through Monday over southern and central portions of that state with concern that particle pollution and ozone concentrations might reach unhealthy levels for people in sensitive groups.
Rain/cooler conditions possible next weekend
Computer models indicate a cold front accompanied by showers and thunderstorms could bring cooler Canadian air into northern Illinois next weekend. Chicagoans may be in store for highs in the 60s, more like late September and early October.
Rain/cooler conditions possible next weekend
Computer models indicate a cold front accompanied by showers and thunderstorms could bring cooler Canadian air into northern Illinois next weekend. Chicagoans may be in store for highs in the 60s, more like late September and early October.
Temperatures should warm into the 80s Monday and a 90-degree high is possible Tuesday as southerly winds invade Northeast Illinois for a two-day stay. The upper-air steering-level winds that have been persistently out of the northwest for days have temporarily shifted more west to southwest. This change will allow the northern edge of very warm air that has been resting over the southern Plains to finally reach the Midwest. The west to southwesterly flow aloft extends to the Northeast coast and into the northern Atlantic, accelerating the movement of weakening Tropical Storm Bill tracking just to the south of Newfoundland and then east out into the northern Atlantic later Monday.
Cooler temperatures return midweek
The passage of a cold front Wednesday signals the shift of the upper-air pattern back to a northwesterly flow which looks to be a semi-permanent fixture the remainder of this week and next. There are indications the front may stall in central Illinois, which could mean extensive cloudiness over Chicago and a good chance of showers or thunderstorms -- especially in southern sections -- Thursday into Friday.
Cooler temperatures return midweek
The passage of a cold front Wednesday signals the shift of the upper-air pattern back to a northwesterly flow which looks to be a semi-permanent fixture the remainder of this week and next. There are indications the front may stall in central Illinois, which could mean extensive cloudiness over Chicago and a good chance of showers or thunderstorms -- especially in southern sections -- Thursday into Friday.
The stormy period that began Sunday afternoon should end later today as a cold front pushes south of of the Chicago area. The Storm Prediction Center posted severe thunderstorm watches Sunday afternoon and evening along the cold front from northern Kansas through northwest Missouri, a good portion of Iowa, northern Illinois, and southern Wisconsin into extreme northern Indiana as well as most of Lower Michigan. Iowa seemed to be hardest hit with many reports of one-and-a-half to two-inch hail along with extensive wind damage. Trees and power lines were down in many locations across southern Wisconsin and Lower Michigan.
Locally heavy downpours were reported in a few spots across northern Illinois. Cloudiness from the storms cut off heating and restricted Chicago area highs to the lower 90s, holding heat indexes to around 100 degrees. Highest readings were at Northerly Island where the high peaked at 93 degrees with a heat index of 103.
Fair skies expected the rest of the week
The upper-air pattern will favor an extended period of fair skies and rain-free weather over Chicago beginning Tuesday and continuing into next weekend.
Locally heavy downpours were reported in a few spots across northern Illinois. Cloudiness from the storms cut off heating and restricted Chicago area highs to the lower 90s, holding heat indexes to around 100 degrees. Highest readings were at Northerly Island where the high peaked at 93 degrees with a heat index of 103.
Fair skies expected the rest of the week
The upper-air pattern will favor an extended period of fair skies and rain-free weather over Chicago beginning Tuesday and continuing into next weekend.
A southwesterly breeze develops Monday, bringing perhaps the warmest readings in three weeks to the area. Chicago's last official high of 86 degrees was recorded back on July 6. It will be close, but that high could be matched or even exceeded in spots across Chicagoland.
A cold front will move slowly through northeastern Illinois Tuesday accompanied by showers and thunderstorms, including some downpours. After that front moves east, cooler and less humid Canadian-source air will flow into the area, and high temperatures will probably fail to reach 80 degrees the rest of the workweek. Thus far, this July is tied with July 1924 as Chicago's fifth-coolest on record since 1871. All of the cooler Julys occurred prior to the 20th century when official observations were taken at various downtown locations near the lakefront.
U.S. weather extremes Sunday
The southwestern U.S. was scorched Sunday with temperatures peaking well above 100 degrees from southern California into Texas. Elsewhere, severe storms featuring funnel clouds, damaging winds and large hail hit the East Coast from Virginia to Massachusetts. Eight people were injured in Readington, N.J., when high winds hit a hot air balloon festival.
A cold front will move slowly through northeastern Illinois Tuesday accompanied by showers and thunderstorms, including some downpours. After that front moves east, cooler and less humid Canadian-source air will flow into the area, and high temperatures will probably fail to reach 80 degrees the rest of the workweek. Thus far, this July is tied with July 1924 as Chicago's fifth-coolest on record since 1871. All of the cooler Julys occurred prior to the 20th century when official observations were taken at various downtown locations near the lakefront.
U.S. weather extremes Sunday
The southwestern U.S. was scorched Sunday with temperatures peaking well above 100 degrees from southern California into Texas. Elsewhere, severe storms featuring funnel clouds, damaging winds and large hail hit the East Coast from Virginia to Massachusetts. Eight people were injured in Readington, N.J., when high winds hit a hot air balloon festival.
Computer models predict a continuation of the persistent upper air pattern that has steered cool Canadian air into the Midwest. Monday southwest winds will briefly boost temperatures into the mid 80s over northern Illinois ahead of an approaching cold front. However this warming will be short-lived, as the cold front sinks into southern Illinois and cooler air returns after another bout of showers and thunderstorms Tuesday. The remainder of the week there will be only minor day to day variations in temperatures with highs averaging about 3 degrees below the seasonal norms.
Potential for Chicago's coldest July since 1891
As of July 25th this July's official Chicago temperatures have averaged 4.4 degrees below normal. If readings for the month end up averaging 4 degrees below normal, this July will be the sixth coldest on record dating back to 1871 and the coldest since 1891. All five of the coldest July's occurred prior to the 20th century when official observations for the city were taken at various locations downtown near Lake Michigan.
The latest attempt at a warm-up in Chicago looks like it will be short-lived. Canadian-source high pressure will hold Monday, continuing a cooling weak northeast wind off Lake Michigan. As the high moves east, winds pick up from the southeast and finally become southwest later Tuesday, allowing warm, moist air to feed into northern Illinois. The approach of a cold front from the northwest will trigger a band of showers and thunderstorms which should hit the Chicago area Tuesday night and early Wednesday. Cool dry high pressure will follow the cold front and hold sway over the Midwest and Great Lakes into next weekend. The southern third of the United States will continue to swelter--in the 90s across the Southeast and more than 100 degrees in the Southwest.
Cool temps not really that unusual here
While this summer has been cool, a closer look at Chicago's 139 years of records shows that the overall average temperatures during the first half of summer 2009 actually barely fall in the coolest third with 91 warmer and 47 cooler. In the 51 years of observations at O'Hare Airport, 2009 ranks as the 14th coolest.
Cool temps not really that unusual here
While this summer has been cool, a closer look at Chicago's 139 years of records shows that the overall average temperatures during the first half of summer 2009 actually barely fall in the coolest third with 91 warmer and 47 cooler. In the 51 years of observations at O'Hare Airport, 2009 ranks as the 14th coolest.
