It is Winter Weather Awareness Week in Wisconsin.   I suppose it’s quite ironic that the first significant winter storm of the season happens to be hitting this week as well.  You will be seeing and hearing a lot of winter weather headlines on TV-9, on the radio, on the Internet, and so forth over the course of winter.   So what is the difference between a Winter Storm Watch and a Winter Weather Advisory?  What can you expect during a Winter Storm Warning versus a Blizzard Warning?  The National Weather Service has put together a nice rundown of the basic meaning of all these advisories.  I’ve published it below.  Check it out.  It should make the winter information a bit easier for you to digest when it comes up.

NWS Winter Weather Information and Terms

It is important that you learn and understand the definitions of different winter related headlines.  Here are the main products used by the NWS to keep people informed.

Hazardous Weather Outlook

The Hazardous Weather Outlook includes any potential weather hazard out to seven days.  It is used for planning purposes and will include a short description of what the weather threat is, when it is expected, and how much it may impact the region.  The HWO is issued daily around 5:00 AM, and updated during the day as needed.  It is also broadcast on NOAA Weather Radio.

Winter Storm Watch

A Winter Storm Watch is issued when there is a potential for a winter storm to affect the region during the next one to three days.  It does not always mean the area will be hit by a winter storm, but there is still some uncertainity of the exact path or timing of the event.  This is a planning stage–use this time to ensure you have supplies at home, like some extra food, medications, baby items, etc.  If travel is planned, check ahead and see if a different route or delaying your departure may make your trip safer.  Be alert for changing weather conditions.

Winter Weather Advisory

Advisories are issued for those winter weather events that are expected to be more of an inconvenience and should not become life-threatening if caution is exercised.  These are often issued for 3 to 5 inches of snow, blowing and drifting snow, freezing drizzle, or a combination of these elements. It may be issued for less snow for early season events, when drivers may not be accustomed to slick roads.

Winter Storm Warning

Winter Storm Warnings are usually issued when dangerous winter weather is expected, occurring, or imminent.  The weather can become life-threatening.  Criteria includes snowfalls of 6 inches or more in 12 hours, 8 inches in 24 hours, or lower amounts if accompanied by strong winds or a combination of dangerous winter elements.  Avoid unnecessary travel.

Blizzard Warnings

The most dangerous winter event is certainly the blizzard.  Blizzard Warnings are issued when snow or blowing snow lowers visibilities to a 1/4 mile or less, wind gusts hit 35 mph or higher, and the storm lasts for 3 hours or more.  Travel is dangerous and should be avoided if possible.

Ice Storm Warning

Ice storm Warnings are issued when freezing rain will cause widespread glazing.  A coating of ice is expected to reach 1/4 inch thick or more on objects and make travel nearly impossible.  For lesser amounts of ice, a Freezing Rain Advisory would be used, but even a thin glaze of ice can make travel difficult.  Avoid travel.

Wind Chill Warning

Issued when wind chills of -35 F or lower are expected.  A Wind Chill Advisory is issued for values of -20 F or lower.  Dress warmly and cover as much exposed skin as possible.

Well, please slow down when driving during the upcoming winter storms.  Remember the first few storms in particular tend to cause a lot of accidents when people are a bit rusty with their winter driving skills.  Leave extra room between you and the vehicles around you, and brake gently.  Here’s wishing you an enjoyable and safe winter!

Posted under Severe Weather, Weather Safety

As Brian and Kristen mentioned over the last couple of days, there is a potential for our first significant snowfall of the season come this Friday night and during the day on Saturday. Right now I am forecasting a 50% chance of rain on Friday changing to snow on Saturday. It is still too far away to add much more certainty to the forecast but as a rough first estimate – if the storm does hit Northcentral Wisconsin – there could be 2 to 4 inches. The snow might stick around as well, since it looks like colder temps will be developing over the weekend and next week. The picture is of the GFS model run from midnight last night (the latest available). It shows a moderate low pressure system with a couple inches of snow for the late afternoon on Saturday.

Perhaps it is fitting that our first threat of snow is coming at the end of Winter Weather Awarenessweek. To start out the week, I will pass along the most important and most effective Winter Weather Safety tip: DON’T DRIVE LIKE A MANIAC! Having a four wheel drive vehicle with all the newest fancy automatic controls and anti-lock brakes only ensures that you will be going faster and die in a more violent crash (often taking others with you) when it does happen. The last time I was on the road during an icing event, my wife and I drove from Wausau to Abbotsford and saw about 10 vehicles in the ditch. All but one were SUVs or Trucks. The SUV drivers thought they were safe, but ended up in the ditch. There is no substitute for driving slower. Plan ahead. When there is snow or ice falling from the sky, leave 10 minutes early for work and drive more carefully.

With the potential for snowfall, we might also finally have our winners in the first snowfall contest. If the storm does produce snow in our area, 1 inch in Wausau (the contest criteria) is a distinct possibility. If I had to forecast, I would say the higher chance of that inch of snow will be on the 13th (Saturday) and not the 12th (Friday). Nine people predicted the 12th and five people predicted the 13th. Good luck! The top 4 prizes include R-store gift cards and car wash coupons.

Now taking an even bigger forecast risk, for all of the hunter’s out there, the GFS computer model (the one reference above) is showing a brutal opening weekend for the gun hunt. Looking almost 2 weeks into the future can be fraught with errors, but I wanted to alert all the hunters that there could be light snow or flurries as well as gusty winds and well below normal temperatures for opening weekend. The CPC 8 t0 14 day outlook also shows a good chance of below normal temps late next week. How cold could it be? High temps could be in the 20s or even a bit lower.

Have a nice Monday! Meteorologist Justin Loew.

Posted under CPC Outlook, First Snowfall 2010, forecast, Freeze, Winter Weather