Weather forecast for Wednesday, January 17, 2024. YouTube Tips ⓘ
According to the NWS Chicago office, very thin precipitation bands, which are difficult to forecast, will be generated along warm advection from the south.
Light and dry snow is forecast in round one to accumulate beginning Wednesday about 8:00 p.m. until about noon Thursday. Most of the snow is forecast to accumulate between 11:00 p.m. and 3:00 a.m. Impacts to the Thursday morning commute are probable with a max total accumulation of 1.9 to 2.0 inches possible by noon Thursday.
A period of snow flurries will continue all day Thursday, and another round of accumulating snow is forecast to begin about 6:00 p.m. Thursday and continue to about noon Friday. The max total accumulation in the second round is forecast to be about 3.3 inches.
Therefore, a max total of 5.3 inches of newly fallen snow is possible from Wednesday night until noon Friday. However, atmospheric conditions could lower the total of the two rounds to about 3 inches.
The Snow/Liquid Ratio is likely to be above 15:1, which is very light, dry snow.
Bitter cold returns Thursday evening through Sunday morning with minimum wind chills in the -25 to -10 degree range.
A warmer system will rain to the area Monday into Tuesday morning, may fall as freezing rain or freeze when the rain hit subfreezing ground temperatures.
Weather Radar in northeast Illinois was clear. The nearest precipitation is over 60 miles away — a thin, weak line from Ottawa to Davenport, Iowa to Cedar Rapids was observed about 4:00 p.m.
See also Arlingtoncardinal.com/clouds
Temperatures will moderate today through Thursday before more cold arrives Friday through Sunday morning. After two mid-week rounds of snow, we’re watching the potential for some locally heavy lake effect snow in northwest Indiana Friday into Friday night. pic.twitter.com/3CpdMgSeku
— NWS Chicago (@NWSChicago) January 17, 2024
O’HARE FORECAST …
Wednesday Afternoon: Partly sunny, with a high near 18. Breezy, with a west southwest wind 10 to 20 mph, with gusts as high as 25 mph.
Tonight: Snow likely, mainly after 11pm. Cloudy, with a low around 13. West southwest wind 5 to 10 mph. Chance of precipitation is 70%. New snow accumulation of 1 to 2 inches possible.
Thursday: A chance of snow before noon, then a chance of flurries between noon and 3pm, then a slight chance of snow after 3pm. Mostly cloudy, with a high near 21. North wind 5 to 10 mph. Chance of precipitation is 40%.
Thursday Night: Snow. Low around 11. Wind chill values as low as -3. North northwest wind 10 to 15 mph, with gusts as high as 25 mph. Chance of precipitation is 100%. New snow accumulation of 2 to 4 inches possible.
Friday: A 40 percent chance of snow. Cloudy, with a high near 15. Blustery, with a northwest wind 15 to 20 mph, with gusts as high as 30 mph.
Friday Night: A 30 percent chance of snow before midnight. Mostly cloudy, with a low around 2.
Saturday: Sunny, with a high near 15.
Saturday Night: Mostly clear, with a low around -3.
Sunday: Mostly sunny, with a high near 18.
Sunday Night: Mostly cloudy, with a low around 16.
Monday: A chance of rain and snow. Cloudy, with a high near 34.
Monday Night: Rain or freezing rain likely. Cloudy, with a low around 32.
Tuesday: Rain likely. Cloudy, with a high near 37.
LAKE TEMPS …
SOUTHERN LAKE MICHIGAN WATER TEMPERATURES
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
908 AM CST Wed Jan 17 2024
LAKE MICHIGAN WATER TEMPERATURES…
CHICAGO SHORE………..36.
CHICAGO CRIB…………36.
MICHIGAN CITY………..34.
SOUTH MID LAKE BUOY…..41.
&&
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 THE WATER SURFACE. IT IS READ EVERY DAY OF THE YEAR.
january.chicagoweatherstation.com
Chicago Weather Forecast for your MAC/PC/TABLET includes surrounding suburbs.
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AREA FORECAST DISCUSSION …
Area Forecast Discussion
National Weather Service
Chicago/Romeoville, IL
301 PM CST Wed Jan 17 2024
.SHORT TERM… Issued at 300 PM CST Wed Jan 17 2024
Through Thursday night…
Key Messages:
* Period of mainly light accumulating snow develops tonight and into Thursday morning. Impacts to the morning commute probable.
A low-amplitude disturbance, currently translating east across Nebraska and South Dakota, will arrive in our region this evening and overnight. Warm advection is expected to ultimately focus two relatively distinct regions of precipitation within separate frontogenetic circulations. As a result, this remains a pretty complicated forecast as small shifts in the placement of what will already be very narrow precipitation bands will result in significant changes to who sees the most snow. It`s conceivable in between these two circulations that mesoscale subsidence drives a local minimum in precip, leading to little or no precipitation, something even at this short range we can`t cleanly depict in our gridded forecast.
The first f-gen band looks like it`ll develop somewhere in the vicinity of the I-88 corridor late this evening as divergence within the right entrance region of a bifurcated upper jet streak pushes overhead. Most guidance suggests the region of associated precipitation will be pencil thin, likely less than 50 miles wide. This band`s staying power may not be all that long, as a secondary circulation is then forecast to develop farther south during the late overnight hours and into Thursday morning, focusing somewhere in the vicinity of a roughly Pontiac to Valparaiso line. Mesoscale subsidence on the northern terminus of this second circulation may result in a pretty rapid evaporation of the first band and additionally yield a “snow hole” somewhere across our western locales in the vicinity of I-80/I-39. Can`t slice the onion nearly that thin in the gridded world to account for additional wobbles, but this speaks to the complicated nature of banded precip.
As indicated by the overnight shift, the nature of this snowfall generally looks to be steady but light, as we`re not dealing with incredibly deep reservoirs of instability overhead. In fact, the associated f-gen circulations remain fairly ephemeral and not overly well developed. As such, it makes sense that we`re not seeing significant -EPV* reductions (indications of areas conducive to slantwise parcel accelerations where vertical static stability exists) in regional cross sections since these are most favored in the vicinity of very tight baroclinic zones and strong(er) wind shear.
As it stands right now, latest indications are the northern (first) snow band focuses bounding I-88 mainly during the 9 pm to maybe 3 am timeframe. This looks like a coating to 1″ type band which may also fight some antecedent lower-level dry air. The southern (second) band then develops and focuses either side of a Pontiac to Valpo line from about midnight to 9 am, with the main focus in a roughly 6 hour period likely bounding the bulk of the morning commute. With the arctic airmass still in place and dee PDGZs, even with generally modest ascent, SLRs will likely shake out above 15:1, so even with the light QPF advertised (under two tenths of an inch), snow accumulations in the second band of 1-3″ looks like a reasonable forecast at this point.
These types of “light” snow events can be really deceptive and impactful, and particularly with how cold road temperatures are, we`re going to see some degree of travel impacts with accumulations on roadways. We`re right on the cusp of winter headlines for this, mainly for the second/southern band. At this point, given uncertainties regarding exact band placement and amounts generally in the 1-3 inch range spread out over several hours, will be holding off in favor of some targeted graphical messaging.
— Carlaw/NWS
&&
.LONG TERM… Issued at 300 PM CST Wed Jan 17 2024
Friday through Wednesday…
Key Messages:
An active period of wintry weather continues through early next week.
* Areawide 2-4″ of snow Thursday night-early Friday AM
* Winter Storm Watch issued for Porter County where snow accums >8″ possible Thursday night through early Saturday AM.
* Bitter cold returns Thursday PM through Sunday AM with minimum wind chills in the -25 to -10 degree range.
* Warmer system brings rain to the area Monday into Tuesday AM, some of which may fall as freezing rain due to subfreezing ground temps.
Thursday Night Snow:
To start, a second round of snow is expected as a shortwave phases with the broader longwave trough on its approach to the area. This is expected to bring widespread accumulating snow to the area beginning by early Thursday evening toward Rockford and spreading southeast through the evening across the rest of the area. QPF has increased with the latest runs by a bit. The continued cold temperatures support SLRs in the 18-20:1 range. This results in widespread 2-4 inches of snow through early Friday morning, highest amounts east along/east of I- 55. This could result in hazardous travel for the AM commute.
Lake Effect Snow Thursday night-early Saturday AM:
Attention quickly turns to the potential for an intense lake effect snow band oriented into northwest Indiana. Modeled lake effect parameters continue to be maxed out: lake-850mb delta-t`s >20C, strong ascent and steep lapse rates in the DGZ. Guidance continues to support a strong land breeze convergence zone developing over the lake oriented into northwest Indiana during this period. This would be supportive of periods of snowfall rates in excess of 2-3 inches per hour at times, especially early Friday morning through Friday afternoon. This would result in dangerous travel conditions across northwest Indiana, including the I-80/I-94 corridors.
For Porter county, the combination of the broader system snow Thursday evening/night and the lake effect snow (with 18-20:1 SLRS) could result in significant snowfall accumulations over 8 inches. As is typical at this range with dominant lake effect snowfall bands, wobbles in its location can impact the timing and duration of greatest impacts. As such, it is possible that during parts of the day on Friday the band shifts east of Porter county into LaPorte and then returns back to the west. Strong winds off the lake gusting up to 35-40mph could result in blowing and drifting snow, especially near the lakeshore.
Will note there is hi-res guidance (HRRR) that has a westerly shift in the initial placement of the band and includes northeast Illinois in higher amounts. At this time think this is too far west, and continue to favor the model consensus being further to the east into Porter County, IN.
Cold Temperatures:
Also can`t ignore the return of bitter cold temperatures Thursday night through Sunday morning where minimum wind chills Friday AM and Saturday AM could once again dip into the -25 to -10 degree range. Continue to limit time outdoors and bundle up to avoid hypothermia/frostbite.
Sunday onward:
Temperatures very gradually begin to warm early next week as a warmer airmass begins to lift into the region. A southwest to northeast oriented jet stream will lift disturbances through the area, the first of which could bring a quick hit of snow Monday morning, though confidence in timing and placement remains low. A second, warmer and larger disturbance lifts across the area Monday night into Tuesday morning. The concern with this system is that warmer mid-level temperatures would be supportive of precipitation falling as liquid (aka rain). Given the frigid snowpack in place across much of the region, surface air temperatures (and ground temps) will likely lag this warming and potentially result in a period of freezing rain. Still too soon to pin down timing and amounts at this range, which will in turn help identify potential impacts. Will continue to monitor this closely over the coming days.
Temperatures then continue to trend warmer than normal with highs in the upper 30s to near 40 forecast by Wednesday!
Petr