Freezing Rain Advisory

A Freezing Rain Advisoryis in effect for all of northern Illinois through Sunday night.  Boone, Carroll, DeKalb, Jo Daviess, Lee, McHenry, Ogle, Stephenson & Winnebago County is under this advisory until 9pm.  Whiteside County is under

the advisory until 6pm.  In southern Wisconsin, a Winter Weather Advisory is in effect for Green, Rock & Walworth County until midnight.  Ice accumulation is possible Sunday afternoon.  Generally 0.1″ to 0.3″ of ice is possible, which would create hazardous travel conditions on untreated roads.  A glaze of ice may also cause scattered power outages.

(9:47 PM) nwsbot: Local Storm Report by NWS LOT: Polo [Ogle Co, IL] co-op observer reports FREEZING RAIN of E0.15 INCH at 09:44 PM CST — 0.15 inches ice accumulation with 0.24 inches total liquid including rain and freezing rain.

9:00pm update:  All Freezing Rain Advisories have been cancelled in Illinois. That doesn’t mean it won’t be icy, though.  Drizzle, fog, and a few showers will still fall on top of the sleet/ice we saw from earlier, keeping things a bit slippery.  Until the temperatures warm into the upper 30s around midnight, use caution! -Joe

7:15pm update: The last of the significant precipitation is moving out of southern Lee and DeKalb County.  We will have patchy drizzle and patchy freezing drizzle possible tonight.  Roads remain slippery and will remain so until temperatures climb into the upper 30s around the midnight hour.  The Freezing Rain Advisory for northern Illinois is set to expire at 9pm. Winter Weather Advisories for southern Wisconsin are still set to expire at midnight. A few rain showers may redevelop in eastern Iowa and drift northeast overnight. -Joe

7:25pm Radar

(7:03 PM) nwsbot: Local Storm Report by NWS DVN: Freeport [Stephenson Co, IL] broadcast media reports FREEZING RAIN of E0.15 INCH at 07:01 PM CST — total ice accumulation

6:00pm update:  The Freezing Rain Advisory for Whiteside County has expired. -Joe

5:15pm update: There are a lot of brighter echos on ExacTrack|HD this evening. A low level jet has allow some convection to form, producing some brief moderate-to-heavy downpours (with isolated thunder and lightning). We just had a quick downpour at WREX….it fell as rain and melted some sleet, but quickly REFROZE as temperatures hover near freezing. We will have this threat for the next few hours. -Joe

(3:20 PM) nwsbot: Local Storm Report by NWS MKX: 2 W Brodhead [Green Co, WI] law enforcement reports LIGHTNING at 03:14 PM CST — thunderstorm with lightning and sleet near brodhead. indicated by nws radar confirmed by green co. law enforcement.

3:10pm update: The freezing rain and sleet has become scattered in nature. Temperatures are hovering around 32 degrees.  Numerous roll over accidents have been reported.  -Joe

2:15pm update:  The back edge of the bulk of the precipitation is along the Rock River.  However, more freezing rain redevelopment is expected in eastern Iowa and will move through the area, although it will be more scattered in nature.  Ice and sleet accumulations have generally been around 0.1″ and we will continue to add to that this afternoon.  Temperatures will begin to rise about freezing later this evening, allowing things to begin to melt.  There have been numerous reports of accidents.  Please use caution if you must travel this afternoon. -Joe

(1:37 PM) nwsbot: Local Storm Report by NWS LOT: W Rockford [Winnebago Co, IL] broadcast media reports FREEZING RAIN of U0.00 INCH at 01:33 PM CST — freezing rain with sleet. minor ice glaze

(1:27 PM) nwsbot: Local Storm Report by NWS MKX: Edgerton [Rock Co, WI] trained spotter reports SNOW of M0.3 INCH at 01:24 PM CST — 3/10 inch new snow in last 1/2 hour. visibility near 1/8 mile. temperature fell from 31 to 28 in last hour.

 

1:15pm update:  Sleet, snow, and freezing rain is occurring across the WREX viewing area with accumulation reports beginning to come in.  The bulk of the precipitation shield is overhead and becoming more scattered in nature over eastern Iowa and far northwest Illinois.  More development is expected this afternoon, although the sleet and freezing rain will become more scattered in nature.  Slippery road conditions will continue to be a concern, with all local temperature reporting stations seeing readings of 29 to 32 degrees

(1:06 PM) nwsbot: Local Storm Report by NWS LOT: Mendota [La Salle Co, IL] amateur radio reports FREEZING RAIN of E0.00 INCH at 01:05 PM CST — light glaze on surface

(1:05 PM) nwsbot: Local Storm Report by NWS LOT: W Rockford [Winnebago Co, IL] broadcast media reports SLEET of U0.00 INCH at 01:01 PM CST — reported by wtvo.

(12:51 PM) nwsbot: Local Storm Report by NWS LOT: Woodstock [Mchenry Co, IL] co-op observer reports SLEET of U0.00 INCH at 12:49 PM CST — sleet first then turned to snow

12:15pm update:  Sleet mixed with snow and freezing rain is falling across the Rockford area.  Minor accumulations have been observed, including here at WREX-TV.

11:15am update:  Freezing rain mixed with sleet and very fine, light snow has been observed in the counties closest to the Mississippi River. -Joe

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Posted under ice, safety, snow, travel, weather, winter weather

This post was written by qni_it on January 27, 2013

Icy, Dicey Sunday

The forecast has remained fairly consistent over the past few days regarding Sunday.  However, there are better indications that the bulk of the precipitation will arrive in Rockford around noon.  A brief period of sleet mixed with freezing rain is possible at the onset, while the afternoon hours should be limited to just freezing rain.  As temperatures hover at or slightly below freezing, significant ice accumulations of 0.1″ to 0.3″ are possible.  However, if the warmer layer of air in the atmosphere is able to influence our surface temperatures, thus allowing temperatures to rise a degree or two, ice accumulations will be reduced.  There is a very thin line between freezing rain and liquid rain.  Regardless of how much ice accumulation we receive, area roads will be slippery and some power outages are possible.

By Sunday evening, our freezing rain will mix with liquid rain and eventually fall as just liquid rain by nighttime.  Temperatures will rise into the middle 30s by 10pm or so.  Patchy fog will form as ice begins to melt with the milder temperatures.

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Posted under fog, ice, safety, travel, weather, winter weather

This post was written by qni_it on January 26, 2013

Weekend Outlook

A wintry mix of snow, sleet, freezing rain, and rain is still in the forecast for Sunday.  Thanks to an exiting area of high pressure, which will keep things calm, cold, and tranquil for Saturday, temperatures will remain below freezing for a good portion of Sunday morning.  The latest model runs continue to pick up on the potential for snow and/or sleet to start falling at the onset on Sunday morning.  Any snow or sleet accumulation will remain minor (about half an inch at most).

As milder air works into the the atmosphere, temperatures aloft will become warmer than at the surface by Sunday afternoon.  Therefore, a changeover to sleet and freezing rain is anticipated by Sunday afternoon.  As many models are averaging around 0.4″ of precipitation (combination of snow, sleet, ice, rain), ice accumulation is remains a major concern.  A Freezing Rain Advisory may be issued in the event of minor ice accumulation.  An Ice Storm Warning is issued when ice accumulations are expected to top a quarter of an inch.  Regardless, travel conditions may become hazardous and property damage and power outages may occur.

Temperatures will continue to rise Sunday evening, eventually topping the freezing mark.  While ice may still accumulate on elevated surfaces with temperatures in the middle 30s, the threat for significant icing will end Sunday overnight.  By Monday, we will climb to near 40 degrees.

Ice is very tricky to forecast.  As soon as we learn any new information we will pass it along to you.  Don’t forget, you can follow us on Twitter: @13wxauthority or @WxJoeA

-Joe

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Posted under ice, rain, safety, snow, travel, weather, winter weather

This post was written by qni_it on January 25, 2013

Icy Sunday Possible

While an Alberta Clipper system is targeting northern Illinois and southern Wisconsin for late Thursday night into early Friday, a wintry mess is just around the corner for Sunday.  While the energy for this wintry mess is still off the coast of California, the timing and strength of this system is still a bit hazy.  What we know is that an area of low pressure will lift northeast out of the southern Plains on Saturday night.

By Sunday morning, precipitation will begin to infiltrate the local area.  With an area of high pressure exiting the region, cold temperatures will be left in its wake.  Because of this, precipitation may begin as snow and sleet.  A minor accumulation is possible before a surge of ‘warmer’ air from the southwest moves in late Sunday morning or early afternoon.  Known as an ‘inversion’ layer, or an increase in temperature with height, milder air aloft will allow liquid to fall from the sky before meeting the colder air at the Earth’s surface.  The liquid then freezes on contact on roads, sidewalks, buildings, and everything on the surface.  With models generating between 0.10″ and 0.60″ inches of precipitation, a major glaze of ice is possible.  Treacherous travel and power outages are definitely a concern.

However, if the milder air infiltrates the region more quickly and temperatures moderate at the surface, we will see a change over to all rain.  Regardless of the time frame, a change over to rain is inevitable, since temperatures will continue to rise into the upper 30s Sunday night and lower 40s for Monday.

Stay tuned, as we will keep you updated with the latest information as quickly as possible.

-Joe

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Posted under ice, rain, safety, snow, travel, weather, winter weather

This post was written by qni_it on January 24, 2013

Snowfall Forecast: Friday Morning

An Alberta Clipper will bring snow to Northern Illinois and Wisconsin late Thursday into early Friday morning. Winter Weather Advisories have been posted for parts of Wisconsin. See all of the weather warnings by clicking here.

As has been the story this winter, this system will bring paltry accumulations to the Rockford Metro. We will be in the 1-3 inch range with 3-6 inches north of a line from Wisconsin Dells to Milwaukee. Locally, the thicker accumulations will fall in Rock and Walworth Counties with a dusting in our far southwest (Whiteside Co.). Futuretrack is placing about a half inch down in Dixon with 2.1 inches around Lake Geneva.

Still, use some extra caution during Friday morning’s commute.

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Posted under snow, weather

This post was written by qni_it on January 24, 2013

What is Wind Chill?

We all know that the actual temperature can be measured on any given day at any given time with a thermometer. It is a finite value that can be measured. Wind chill on the other hand is a value that can’t be directly measured with an instrument. It is a perceived temperature based on the actual temperature and wind speed. The is the winter equivalent to the summer heat index, however the heat index is a calculation of the “feels like” temperature that uses humidity instead of wind speed. The human body is naturally always losing heat through our skin. When heat loss occurs, it forms a warm boundary layer just above the surface of the skin (think of feeling the air just outside of a warm pot or pan). Wind disrupts this boundary layer by blowing away the lingering heat and allowing cooler air to come in contact with the warm surface of the skin. The attempt of our skin to maintain a steady temperature in harsh wind and faster heat loss results in a perceived lower temperature and an actual greater heat loss by our bodies. The stronger the wind, the quicker this heat loss happens. This extreme heat loss can cause hypothermia or frostbite if someone is exposed to frigid temperatures and harsh wind for an extended period of time. The formula to calculate wind chill is long and derived from other mathematic equations, however the results based upon specifc wind speeds and temperatures have been made into the attached graph. -Greg

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Posted under cold blast, winter weather

This post was written by qni_it on January 24, 2013

More snow Thursday Night

Joe Astolfi blogged last hour about the snow that fell in parts of the area today (including an update to our deficit). Now, we’re setting our sights on our next accumulating snow. According to the four reliable models, we’re in for only 0.07″ of liquid equivalent precipitation. Because temperatures will be quite cool, this will be a fluffy snowfall (fluffy snow accumulates better than wet snow (which compacts)).

Just taking the average and then assuming we’ll have a snow-water ratio of 25 to 1 yields just under 2 inches of accumulation by early Friday. -Eric

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Posted under snow

This post was written by qni_it on January 23, 2013

Light Snow Adds Up

A weak Alberta Clipper system that dived south out of Canada brought some light snow to northern Illinois and southern Wisconsin on Wednesday.  Nearly all of us picked up a light dusting of snow.  Some locations picked up a bit more, especially west of the Rock River.  Galena led the way with 2 inches, observed just southeast of town.  Both Freeport and Dixon picked up around an inch to an inch and half.

At Chicago Rockford International Airport, about a quarter of an inch was observed (similar to most local areas).  How does Rockford fare this season, now that meteorological winter is halfway over?  Not surprisingly, our snowfall deficit is significant: nearly 18 inches below normal!  At RFD, only 2.9 inches of snow has fallen this season.  While measurable snow (0.1 inches or more) has occurred on just 6 days, a trace amount of snow occurred on 17 days!  A ‘trace’ means that snow has fallen, but it’s not significant enough to measure (less than 0.1 inches).

Our next snow maker will come in the form of another Alberta Clipper late Thursday into Friday.  Another round of light snow with similar accumulations can be expected.

-Joe

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Posted under drought, snow, statistics, weather, winter weather

This post was written by qni_it on January 23, 2013

Smoking Radar

Late last night fire crews battled a massive 5 alarm fire on Chicago’s South Side in the Bridgeport neighborhood. The blaze was so large and so intense that it emitted huge amounts of smoke as firefighters tried to calm the flames. The amount of smoke was so extensive that due to our precipitation free night, doppler radar readings were able to pick up the smoke plume and showed where the smoke was being blown (over Lake Michigan due to a westerly breeze). This isn’t the first time that non-weather related things have been picked up by radar. Others include wind turbines on a calm clear night, and even migrating birds! -Greg

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Posted under event, First Look

This post was written by qni_it on January 23, 2013

Alberta Clipper coming

While some light snow showers or flurries will fall over our area on Wednesday, a more potent Alberta Clipper system will provide some shoveling snow Thursday night into Friday.

Here’s the set up. The jet stream will be directly overhead with winds increasing to nearly 200mph at 30,000 feet. This will bring a disturbance down from the southern provinces of Canada on Thursday. Typically, Alberta Clippers don’t produce massive amounts of snow. However, with a colder airmass in place and gusty wind, the snow could accumulate modestly with a little bit of blowing.

The GFS model (to the left shows the potential for sticking snow, the worst of which should fall across Wisconsin. There isn’t any question what precipitation type we’ll have. Notice how far south the rain/snow line is! Current indications are for 1-3 inches of snow to fall in our area with a 2-4 inch snow widespread north of Madison and Milwaukee.

An additional system bears watching for Sunday. Another coming just beyond the 7 Day Forecast, possibly in a week to 8 days. We’re definitely entering a more active weather pattern. -Eric

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Posted under weather

This post was written by qni_it on January 22, 2013