NWS Forecast for O'Hare International Airport Chicago, IL Last Update: 9:42 pm CDT Oct 24, 2024
Hazardous Weather Outlook below forecast ...
Thursday Night: Showers and thunderstorms before 4am, then showers likely and possibly a thunderstorm between 4am and 5am, then a chance of showers and thunderstorms after 5am. Some of the storms could produce heavy rainfall. Low around 51. South wind 5 to 10 mph. Chance of precipitation is 90%. New rainfall amounts between a half and three quarters of an inch possible.
Friday: A 30 percent chance of showers, mainly before 8am. The rain could be heavy at times. Cloudy, then gradually becoming mostly sunny, with a high near 61. South southwest wind 5 to 10 mph becoming north northwest in the afternoon. Winds could gust as high as 15 mph.
Friday Night: Mostly clear, with a low around 41. North northwest wind around 10 mph, with gusts as high as 15 mph.
Saturday: Sunny, with a high near 57. North wind 5 to 10 mph.
Saturday Night: Mostly clear, with a low around 38. North northeast wind around 5 mph becoming calm in the evening.
Sunday: Sunny, with a high near 61.
Sunday Night: Mostly clear, with a low around 44.
Monday: Mostly sunny, with a high near 67.
Monday Night: Mostly cloudy, with a low around 59.
Tuesday: Partly sunny, with a high near 78. Breezy.
Tuesday Night: Mostly cloudy, with a low around 65. Breezy.
Wednesday: A chance of showers. Partly sunny, with a high near 77. Breezy.
Wednesday Night: Showers likely. Mostly cloudy, with a low around 56.
Thursday: Showers likely. Partly sunny, with a high near 65.
Thursday Night: Showers and thunderstorms before 4am, then showers likely and possibly a thunderstorm between 4am and 5am, then a chance of showers and thunderstorms after 5am. Some of the storms could produce heavy rainfall. Low around 51. South wind 5 to 10 mph. Chance of precipitation is 90%. New rainfall amounts between a half and three quarters of an inch possible.
Friday: A 30 percent chance of showers, mainly before 8am. The rain could be heavy at times. Cloudy, then gradually becoming mostly sunny, with a high near 61. South southwest wind 5 to 10 mph becoming north northwest in the afternoon. Winds could gust as high as 15 mph.
Friday Night: Mostly clear, with a low around 41. North northwest wind around 10 mph, with gusts as high as 15 mph.
Saturday: Sunny, with a high near 57. North wind 5 to 10 mph.
Saturday Night: Mostly clear, with a low around 38. North northeast wind around 5 mph becoming calm in the evening.
Sunday: Sunny, with a high near 61.
Sunday Night: Mostly clear, with a low around 44.
Monday: Mostly sunny, with a high near 67.
Monday Night: Mostly cloudy, with a low around 59.
Tuesday: Partly sunny, with a high near 78. Breezy.
Tuesday Night: Mostly cloudy, with a low around 65. Breezy.
Wednesday: A chance of showers. Partly sunny, with a high near 77. Breezy.
Wednesday Night: Showers likely. Mostly cloudy, with a low around 56.
Thursday: Showers likely. Partly sunny, with a high near 65.
Hazardous Weather Outlook
National Weather Service Chicago/Romeoville IL
244 PM CDT Thu Oct 24 2024
Winnebago-Boone-McHenry-Lake IL-Ogle-Lee-De Kalb-Kane-DuPage- La Salle-Kendall-Grundy-Kankakee-Livingston-Iroquois-Ford- Northern Cook-Central Cook-Southern Cook-Northern Will- Southern Will-Eastern Will-Lake IN-Porter-Newton-Jasper-Benton- 244 PM CDT Thu Oct 24 2024 /344 PM EDT Thu Oct 24 2024/
This Hazardous Weather Outlook is for portions of north central Illinois...northeast Illinois and northwest Indiana.
.DAY ONE...Tonight.
Weather hazards expected...
Limited Thunderstorm Risk.
DISCUSSION...
Showers and a few embedded thunderstorms will move across the area late this evening into early Friday. While no severe weather is expected, locally heavy rainfall is possible, especially between the I-80 and I-90 corridors.
.DAYS TWO THROUGH SEVEN...Friday through Wednesday.
Friday... Limited Thunderstorm Risk in the morning east of I-55.
.SPOTTER INFORMATION STATEMENT...
Spotter activation will not be necessary through tonight.
GENERAL STORM MOTION OF THE DAY:
Moving toward the east at 40 mph.
$$
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
633 PM CDT Thu Oct 24 2024
.KEY MESSAGES...
- Widespread showers and embedded storms are expected tonight into Friday morning.
- Increasingly strong/gusty winds early next week. Monitoring fire weather concerns on Monday and possibly Tuesday.
- Record warmth possible on Tuesday.
&&
.DISCUSSION... Issued at 301 PM CDT Thu Oct 24 2024
Through Friday Night:
Skies are mostly clear this afternoon with temperatures rising into the low to mid 60s. However, attention turns toward a mid level wave moving northeast out of northern Missouri and a longer upper level wave moving over the northern Plains. These waves will merge as they move east across the forecast area tonight providing a soaking rain to much of the area. Lightning has already been observed in Northern Missouri. As the front moves through, forcing will be strong enough with steep mid level lapse rates for chances of embedded thunder with the showers overnight. There has been a consistent signal for anomalously high precipitable water amounts to advect into the region ahead of it and with strong elevated f-gen circulations embedded in the system, higher rain rates are possible. While much of the area will get up to a half an inch of rain, there could be localized areas between the I-80 and I-90 corridor could receive up to or just over an inch of rain -- though better chances are west of the Fox Valley.
This system is expected to be fairly progressive, arriving late tonight and exiting to the east just after daybreak with lingering showers in northwestern Indiana through late morning. Winds will turn to the northwest behind the cold with gusts u Pto 20 mph through Friday afternoon. Skies will slowly clear through the day, but with a cooler air mass filtering in, low 60s are expected with areas closer to the Wisconsin border remaining in the upper 50s. Temperatures will continue to cool under clear skies Friday night leading to temperatures once again dropping down to just above the freezing mark Saturday morning. Temperatures in the city of Chicago and around Lake Michigan should remain in the low 40s.
DK
Saturday through Thursday:
Cooler and drier conditions will return this weekend as surface high pressure settles into the region in the wake of Friday`s frontal passage. Saturday should feature seasonable temperatures ranging from the mid 50s to the low 60s and clear/mostly clear skies. While cirrus may prohibit optimal radiational cooling conditions from being realized Saturday night, the dry air mass and light/calm winds should nevertheless support temperatures falling to near or below freezing outside of the Chicago metro. Urban heat island and marine influences should keep lows closer to or above 40F in the heart of the Chicago metro and in the immediate vicinity of the Lake Michigan shore. Sunday should be a few degrees warmer than Saturday as winds flip around to a southerly direction on the backside of the surface high and nearly full sunshine has another day to warm the air mass in place over the region. Both days should feature afternoon relative humidity levels falling to near or below 30% across much of the area, but winds remaining on the lighter side should preclude an elevated threat for fires to spread.
Following the departure of the weekend surface high pressure bubble, a more active weather pattern is slated to take hold of the region next week as a deep upper-level trough imposes itself over the western 2/3rds of the CONUS. Forecast guidance continues to illustrate a rather impressive low-level mass response induced by the approaching trough, highlighted by the development of a 50-60+ kt southwesterly 850 mb jet extending from the southern Plains all the way through the Great Lakes during the first half of next week. Needless to say, it looks like it will be quite breezy here during this early-mid week time frame. At this time, Tuesday appears that it will be the day with the strongest winds for us locally and the main day to monitor for a potential wind headline issuance sometime down the road.
Out ahead of the deep longwave trough, a more subtle shortwave disturbance will flutter into the Upper Midwest late Monday into Tuesday. There has been a slight uptick in QPF output over our CWA Monday night into Tuesday morning amongst members of the EPS and GEFS, and with forecast soundings depicting steep mid-level lapse rates as this shortwave passes by, suppose that some high-based convection could sprout somewhere in the northern half or so of our forecast area before chances for precipitation cease as the shortwave departs. However, antecedent dry air through the lowest 2/3rds of the tropospheric column and the strongest forcing for ascent remaining displaced to our north suggest that the overall chances for measurable precipitation here remain quite low and conditional, so saw no need to stray from the NBM`s blended PoPs, which keep most of our forecast area dry for now. Either way, meaningful rainfall does not appear likely during this late Monday-early Tuesday time period.
With fine fuels otherwise expected to dry out again over the weekend into early next week, the breezy southerly winds early next week could bring about heightened fire weather concerns on Monday and/or Tuesday. Dew points/relative humidity levels remain the main question mark in the early week fire weather puzzle as the strong southerly flow will advect in better moisture from down south, but just how quickly this will occur and to what extent mixing will scour out the higher surface dew points remains uncertain at this time. Either way, both Monday and Tuesday will be days to keep a close eye on with respect to fire weather with Monday featuring the lower dew points and afternoon relative humidity levels and Tuesday having higher dew points/humidity levels but likely stronger winds and warmer temperatures. The degree to which we are able to mix on Tuesday will also help dictate just how warm we will get, and while this is still a point of uncertainty in our forecast, progged 925 mb temperatures suggest that the high temperature records for October 29th for both Chicago and Rockford (78 and 81, respectively) will at least be threatened, if not broken.
Eventually, a sharp cold front associated with the aforementioned trough should track across the area on either Wednesday or Thursday of next week and will likely be accompanied by anafrontal rain as it does so. The latest NBM highlights late Wednesday night into Halloween morning as the most likely time frame for rain to occur, but will continue to note a large spread remains in ensemble guidance regarding the timing of the cold frontal passage and when it will bring rain to the area (and how much), so those with outdoor plans for Halloween should continue to check back for forecast updates over the coming days.
Ogorek
&&
.AVIATION /00Z TAFS THROUGH 06Z FRIDAY/... Issued at 633 PM CDT Thu Oct 24 2024
Forecast concerns include...
Chance of thunderstorms tonight. Showers tonight through mid morning Friday. Mvfr, possible ifr cigs overnight/Friday morning.
Showers are expected to spread across the terminals overnight, perhaps very late this evening at RFD and continue through at least daybreak, likely becoming more scattered and then ending by mid morning Friday. The rain may be moderate to briefly heavy at times overnight. There remains uncertainty for thunderstorm coverage. There will likely be some thunderstorms and current prob mention has the time period covered well. However, they may end up being isolated. Trends will need to be monitored this evening for possible adjustment to the thunder forecast.
Cigs are expected to lower to low vfr, 3-4kt, as the rain begins and then will lower further to mvfr by the predawn hours. Its possible ifr cigs may develop before daybreak, especially across northwest IL and at RFD. Mvfr cigs will then slowly lift as the showers end Friday morning and scattered out by early Friday afternoon, from northwest to southeast across the area.
South/southeast winds this evening will slowly turn southerly overnight and then to the south/southwest in the predawn hours. Winds will shift west/northwest as the rain ends mid morning and then to the northwest by early Friday afternoon. Some gusts into the 15-20kt range will be possible Friday afternoon. Northwest winds will continue Friday evening with speeds expected to diminish under 10kt. cms
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...None.
&&
$$
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