ECMWF Wins for Long Term Forecast Accuracy; Too Bad We Didn’t Choose It
Snowfall amounts from the hourly forecast have trended downward for Arlington Heights and nearby communities, and no snow materialized overnight Wednesday/Thursday (as was forecasted). The ECMWF model (European Model) turned out to be the accurate model, which involved a more southerly track. A Winter Weather Advisory still exists and a Flood Advisory is activated for Arlington Heights and nearby suburbs. However, no additional rain is forecast and most snow pack has already melted, so general flooding of low lying areas is not expected to be severe. Areas near rivers and streams may experience flooding from recent moderate rainfall and snowmelt.
Arlington Heights/Nearby
1.60 inches of snow from 2 PM to 8 PM Thursday.
On Wednesday, February 16, 2022, O’Hare International Airport and areas south were upgraded to a Winter Storm Warning. However, Thursday morning, O’Hare and nearby areas were downgraded back to a Winter Weather Advisory.
Instead of severe weather impacting south Chicagoland, a very dangerous winter storm is forecast to impact central Illinois into northern Indiana this afternoon and evening with near blizzard conditions. The area around University of Illinois Urbana-Champaign is likely to be one of the hardest hit areas.
Highlights of forecast changes for Thursday:
According to NWS Chicago an extremely dangerous winter storm with near blizzard conditions is forecast for southern tier of counties — dangerous for wind and blowing snow more so than deep snow. NWS Chicago has shifted the forecast of Thursday’s band of heavy snow south about 50 miles, downgraded northern tier of Winter Storm Warning to a Winter Weather Advisory, and canceled northwest portions of the Winter Weather Advisory. Apparently in forecasts for the past several days, multiple weather forecasting offices favored the wrong models, while having less confidence in the European Model (ECMWF).
Map shows snow cover and ECMWF data. Tap an area to get forecast model inches of snow depth (new snow) for specific areas. The 5:30 p.m. Thursday look at the ECMWF showed about 1.1″ accumulation of snow at 10:00 p.m. Thursday for Arlington Heights. The hourly forecast around Arlington Heights indicates about 1.6 inches of snow.
According to the NWS Chicago, the past five or so days of guidance was split regarding the track and intensity of Thursday afternoon’s secondary shortwave. The GFS & NAM models were both north and stronger, while the ECMWF was south and weaker. In a rather surprising turn of events the models forecasting the northern track (GFS, NAM, ARW, HRRR, etc) all shifted notably south and indicated a weaker system with Thursday afternoon’s wave. There is now very strong multi-model consensus aligned wit the solution the ECMWF has presented for the past several days. According to the NWS Chicago, forecasters typically prefer not to make wholesale changes to forecast at this “stage in the game”, but given the trends in guidance and after collaboration with the Weather Prediction Center and surrounding Weather Forecast Offices, NWS Chicago has decided to make some sizable changes to the latest forecast.
Most notably, NWS Chicago shifted the axis of forecasted heavy snowfall about 50 miles further south. This necessitated some adjustments to the watches and warnings from Chicago west and southwest. The northern edge of the Winter Storm Warning area is now between Joliet and Manhattan, Illinois. The northern edge of the Winter Storm Warning Wednesday evening was as far north as O’Hare International Airport. While there is a period of impactful, accumulating snow still likely from LaSalle County east northeast to Chicago, it appears the duration and magnitude of the impacts will not be as great as previously forecasted. Also, impacts will be less severe than previously feared across northern portions of the County Warning Area (CWA). According to NWS Chicago, the southern portions of our CWA look likely to experience a very dangerous, quick hitting, but high impact snow storm this afternoon into the early evening.
Thursday afternoon’s shortwave trough is depicted quite nicely on water vapor imagery early this morning moving into the panhandles region of the southern plains. Guidance ejects this shortwave trough quickly northeast across central Illinois to the eastern Great Lakes by midnight tonight. While the wave is expected to be dampening as it races across the area, a fast moving surface low will deepen slightly as it tracks from eastern Oklahoma early this morning to central Ohio this evening.
A band heavy snow is likely to develop from eastern Kansas into central Missouri this early this morning, then rapidly move and develop east-northeast into central Illinois and northern Indiana this afternoon. Strong forcing/ascent is expected with coupled upper jet structure this afternoon along with deep/strong frontogenetic circulation in the right entrance region of the nearly 180kt 250mb jet jet. In addition to the forecasted strong mesoscale and synoptic forcing for ascent, this system will have unseasonably moist airmass feeding into the band via the cold conveyor belt.
Vertical cross sections through the strong f-gen circulation depicts very deep layers of strongly negative saturated negative EPV (Equivalent Potential Vorticity), indicative of convective instability, likely a reflection of both very moist airmass and very steep 700-300mb lapse rates. Lightning and thunder is possible in the heavy snow band this afternoon across central Illinois into northern Indiana. Regardless of whether or not lightning occurs, HREF (High Resolution Ensemble Forecast) guidance depicts strong consensus snowfall hourly snowfall rates >1″ per hour and up to 30% chance of snowfall rates exceeding 2″ per hour. Snowfall totals of 6-10″ look likely over east central IL east into Northwest Indiana south of the Kankakee River.
As if the snowfall wasn’t enough, the tightening pressure gradient and strong isallobaric response as a result of the rapid movement of the system will likely produce a period of very strong winds this afternoon. Gusts of 30-40 mph could accompany the very heavy snowfall resulting in near blizzard conditions. Very strong consideration was given to an upgrade to a blizzard warning for Ford, Iroquois, Benton, Newton, and Jasper Counties, but will probably hold off due to potential for wet snow to not be very prone to blowing. Will continue to monitor upstream observational trends and an upgrade to a blizzard warning may yet be needed this morning.
As quickly as the system arrives today it will depart this evening with snow ending from west to east. Some lake effect snow could continue for a couple hours late this evening across Porter County resulting in some minor additional accumulations.
RADAR
Weather Radar shows no precipitation in northeast Illinois and weakening precipitation across East-Central Illinois and Northeast Indiana.
See also Arlingtoncardinal.com/clouds
Periods of rain continue to move across the area this eve. The combination of the rain and runoff from snowmelt will cause flooding, especially in low-lying areas. Expect the rain to change to snow from northwest to southeast overnight. #ilwx #inwx pic.twitter.com/Ytpv1VPC3d
— NWS Chicago (@NWSChicago) February 17, 2022
Here's a rough timeline of the different types of precipitation we're expecting tonight through Thursday. Note many will see a break Thursday morning before the worst of the storm arrives in the afternoon. #ilwx #inwx pic.twitter.com/7BLm8Eh93e
— NWS Chicago (@NWSChicago) February 16, 2022
Note that shifts in the axis of heaviest snow may yet occur. Regardless of where the most snow falls, conditions Thursday afternoon will be hazardous across much of northeastern IL and northwestern IN due to the strong northeasterly winds. #ilwx #inwx https://t.co/0UxhjAMGLp
— NWS Chicago (@NWSChicago) February 16, 2022
Winter Weather Advisory URGENT – WINTER WEATHER MESSAGE…CORRECTED National Weather Service Chicago IL 428 AM CST Thu Feb 17 2022 (including Arlington Heights)
ILZ013-103-171815- /O.CAN.KLOT.WW.Y.0010.000000T0000Z-220218T0300Z/ /O.COR.KLOT.WW.Y.0011.220217T1800Z-220218T0300Z/ DuPage-Northern Cook- Including the cities of Naperville, Wheaton, Downers Grove, Lombard, Carol Stream, Evanston, Des Plaines, Schaumburg, Palatine, and Northbrook 428 AM CST Thu Feb 17 2022
…WINTER WEATHER ADVISORY IN EFFECT FROM NOON TODAY TO 9 PM CST THIS EVENING…
* WHAT…A period of wind driven snow expected. Total snow accumulations of up to two inches.
* WHERE…DuPage and Northern Cook Counties.
* WHEN…From noon today to 9 PM CST this evening.
* IMPACTS…Plan on slippery road conditions. The hazardous conditions could impact the morning or evening commute.
PRECAUTIONARY/PREPAREDNESS ACTIONS…
Slow down and use caution while traveling.
The latest road conditions for Illinois can be obtained on the internet at www.gettingaroundillinois.com.
Winter Weather Advisory URGENT – WINTER WEATHER MESSAGE…CORRECTED National Weather Service Chicago IL 428 AM CST Thu Feb 17 2022 (including O’Hare International Airport)
ILZ104-171815- /O.CAN.KLOT.WS.W.0004.220217T2000Z-220218T0300Z/ /O.COR.KLOT.WW.Y.0011.220217T1800Z-220218T0300Z/ /O.CAN.KLOT.WW.Y.0010.000000T0000Z-220217T2000Z/ Central Cook- Including the cities of Chicago, Cicero, Oak Lawn, Oak Park, and La Grange 428 AM CST Thu Feb 17 2022
…WINTER WEATHER ADVISORY IN EFFECT FROM NOON TODAY TO 9 PM CST THIS EVENING… …WINTER STORM WARNING IS CANCELLED…
* WHAT…A period of wind driven snow expected. Total snow accumulations of 1 to 4 inches. Winds gusting as high as 35 mph.
* WHERE…Central Cook County.
* WHEN…From noon today to 9 PM CST this evening.
* IMPACTS…Plan on slippery road conditions. Patchy blowing snow could reduce visibility. The hazardous conditions could impact the evening commute.
PRECAUTIONARY/PREPAREDNESS ACTIONS…
Slow down and use caution while traveling.
The latest road conditions for Illinois can be obtained on the internet at www.gettingaroundillinois.com.
O’HARE FORECAST …
Thursday: Snow likely, mainly after 2pm. Cloudy, with a temperature falling to around 23 by 5pm. Blustery, with a north wind 15 to 20 mph, with gusts as high as 30 mph. Chance of precipitation is 70%. New snow accumulation of 1 to 2 inches possible.
Thursday Night: A 40 percent chance of snow before 9pm. Cloudy during the early evening, then gradual clearing, with a low around 12. Blustery, with a north northwest wind 15 to 20 mph decreasing to 5 to 10 mph after midnight. Winds could gust as high as 30 mph.
Friday: Sunny, with a high near 31. Breezy, with a west wind 5 to 10 mph becoming southwest 15 to 25 mph in the morning. Winds could gust as high as 35 mph.
Friday Night: A chance of flurries before midnight. Partly cloudy, with a low around 11. Breezy, with a southwest wind 15 to 20 mph becoming west northwest after midnight. Winds could gust as high as 30 mph.
Saturday: Sunny, with a high near 24.
Saturday Night: Partly cloudy, with a low around 19.
Sunday: Mostly sunny, with a high near 48. Breezy.
Sunday Night: Mostly cloudy, with a low around 34.
Washington’s Birthday: A slight chance of rain after noon. Cloudy, with a high near 38.
Monday Night: Rain and snow. Cloudy, with a low around 31.
Tuesday: Snow likely. Cloudy, with a high near 34.
Tuesday Night: A chance of snow. Mostly cloudy, with a low around 20.
Wednesday: Mostly cloudy, with a high near 27.
LAKE TEMPS …
SOUTHERN LAKE MICHIGAN WATER TEMPERATURES
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
905 AM CST Wed Feb 16 2022
LAKE MICHIGAN WATER TEMPERATURES…
CHICAGO SHORE………33.
CHICAGO CRIB……….35.
MICHIGAN CITY……….33.
&&
M IS FOR MISSING DATA THAT IS NORMALLY AVAILABLE.
THE MICHIGAN CITY WATER TEMPERATURE SENSOR IS LOCATED AT A WATER
INTAKE ONE MILE OFFSHORE AND 60 FEET BELOW WATER SURFACE. IT IS READ EVERY DAY OF THE YEAR.
february.chicagoweatherstation.com
Chicago Weather Forecast for your MAC/PC/TABLET includes surrounding suburbs.
^^ MOBILE? USE VOICE MIC ^^
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