Amaze Your Friends During Tonight's Storm

Wanna really geek out (like me) on tonight's snowstorm?  Here are 3 ways to amaze your friends with your meteorological savvy:

1. Pay attention to wind direction.  For most of the day and evening, the wind will be coming from the west.  When it starts to switch counter-clockwise -- first to the southeast, then to the east, then to the northeast -- you'll know that the heaviest band of snow is imminent.  That's because the heaviest bands of snow always fall to the northwest of the center of the low pressure system.  So, if the low is centered just south of Chicago, for instance, the counter-clockwise wind will put us in a northeastern wind, and to the northwest of the low -- the perfect recipe for a heavy snow band in south-central Wisconsin.
2. Strike up a conversation about "water content."  Fun fact: in a typical Wisconsin snowstorm, ten inches of snow would equate to one inch of rain -- meaning the water content in the snow is only about 10%.  When snowstorms come from the south, bringing gulf moisture with them, water content can be more like 30-40%.  This particular storm, however, will have even less water content than the average storm, because it has very little oceanic moisture to draw from.  The snow develops not because of moisture, but because of strong energy and lift in the upper atmosphere.  
3. Talk climatology.  And deer hunting.  Here are some fun facts: A) the average November snowfall in our area is about 2.5 inches; B) if we get 9 inches of snow, that will amount to 20% of the 45 inches we usually get in an average winter; C) the first regulated Wisconsin deer hunt was in 1851; D) last year on the eve of gun season, a warm front came through on Friday night, resulting in fog advisories on Saturday morning.  Near my house, at least, this didn't stop people from shooting at things they thought might be deer.

Any other fun stuff you want to know?

Storm Track, Intensity Now More Certain

Did your iPhone beep at 4:15 this morning?  That's because southern Wisconsin is now under a Winter Storm Warning.

Now just 12 hours in advance of the season's first major snowfall, the track and intensity of the storm appears even more certain.  Many models show the storm as more intense, and not quite as compact, as what was previously thought.

Snow should start right around dinner time tonight.  I'll be watching it from Kristi's Restaurant in New Glarus.  It'll get heavy at times overnight and start to taper late tomorrow morning -- except for those of you in far southeastern Wisconsin, where some lake enhanced snow will linger until late afternoon Saturday.

I'm going to stand by yesterday's predictions, knowing that I might be a little low when all is said and done.  It's quite possible that New Glarus could be more in the 8-9" range, rather than the 6-7" I predicted yesterday.

Here are some of the vital maps.  Click any image to enlarge.

First, the watch/warning area.  Areas in pink represent a Winter Storm Warning.  This is a wider north-to-south area than what was originally expected.

Here's The Weather Channel's current snowfall forecast, putting extreme southern Wisconsin in an 8-12" area.  They've named this storm "Bella."  I hate this practice of naming winter storms.

Here's the local WISC-TV snowfall map.

Here's the text of the Winter Storm Warning.

And finally, here is my list of the vital preparations you should take today:

• Get gas and oil for your snowblower; test start your snowblower
• Stock up on booze
• Find some sucker to take your Badger football tickets tomorrow
• Watch this video from my favorite amateur weather forecaster

Let me know if you have any questions or additional preparation tips!

Friday Night Snow in Southern Wisconsin

Deer hunters must be absolutely giddy about this.  When gun season opens Saturday morning, they'll be greeted by a fresh blanket of snow with which to track deer and keep their Busch Light cold.  

We're still a good 36 hours away from it, but there's some agreement in some computer models about southern Wisconsin's first snow event of the season.

There is significantly less agreement among forecasters about how much snow we'll get.  Forecasts still range from completely non-committal, to "light accumulations" to AccuWeather's aggressive 6-10" forecast.  Here's that map:

Officially, the National Weather Service has issued a Winter Storm Watch from 6pm Friday to 3pm Saturday.  That watch calls for snow ranging from 4 to 7 inches in extreme southern Wisconsin (Madison and Milwaukee included) and Northern Illinois.

Here's what's pretty certain:

• Low pressure will approach from the west late Friday
• It'll be a pretty fast-moving system
• Temperatures will support mainly snow, as a cold pocket sets up today and tonight
• It'll drop the heaviest snow in a narrow, elongated band
• Temperatures Saturday night will be the coldest of the season (mid-teens with single digit wind chills)

What's less certain:

• Exact track of the low, although most models show the Wisconsin/Illinois border as a primary focal point
• System strength (how low the pressure gets)
• The potential for brief lake-effect snow midday Saturday along Lake Michigan (from Sheboygan to Kenosha)

Storm track is always a key ingredient in predicting how much snow will fall in any one place, but in this case, the track is particularly important.  That's because the storm is very compact.  A nudge to the north or south changes snow totals dramatically.  If it does nudge, I think it nudges south.  Here's how Mateo Earth sees it at 4:00am Saturday morning...

Here are my early projections for snow fall, starting 6pm Friday and ending Noon Saturday:

Wisconsin Dells:  1-2"
Madison:  5"
New Glarus:  6-7"
Milwaukee:  7" (possibly more at the lakeshore)

Updates to come, especially if the track fluctuates!

Rippeology Winter Preview for Southern Wisconsin

Rippeology is back for the winter season.  Try to contain your excitement.

The Cliff's Notes version of this post:

• Milder temperatures
• Fewer snow events (but not necessarily less snow than normal)
• More ice events
• A brown Christmas
• An active February

All of those predictions, if they materialize, can be blamed on what is now the second strongest El Nino on record.  Only the El Nino event of 1997 was more intense.  The current El Nino may still surpass it, but I doubt it. 

El Nino is basically a warming of surface water temperatures in the eastern and central Pacific near the equator.  This phenomenon results in some pretty solid weather trends for North America.  Among those is a drier and warmer winter in the Midwestern section of the United States.

At first glance, those "warmer and drier" deviations may seem small.  Generally, El Nino would mean our average temperatures during the December/January/February "meteorological winter" might be 2-4 degrees above normal...and snowfall might come in 3-5 inches under seasonal averages.  But in 1997-98, El Nino produced a greater disparity for southern Wisconsin -- with temperatures averaging 7-8 degrees above normal, and snowfall averaging as much as 10 inches below normal.   

Here's a great summary of the '97-'98 El Nino from the National Weather Service out of Milwaukee.

The "nuance" of El Nino (for us, anyway) is that for warmer temperatures to occur, you need a greater frequency of south/southwesterly wind patterns.  And a few degrees can make a huge difference.

In the Madison area, the lowest average temperature in winter is 27 degrees.  That occurs in mid-January.  Add a few degrees to that average, and you're nearer the freezing mark.  Add a southerly wind flow, and you have the perfect recipe for ice storms, as warmer air overrides colder temps at the surface -- hence my prediction of more icing events above.

That more frequent southerly flow also diminishes, in theory, anyway, the frequency of Alberta Clipper snowstorms -- those fast-moving lows from the northwest that dump moderate amounts of drier, fluffier snow.  Hence my prediction of fewer snow events.

But if you start at the source of El Nino...add a south/southwesterly wind flow...mix it with intense low pressure in the New Mexico/Texas area, you increase the chances of the snowstorms that dump the most snow on southern Wisconsin -- panhandle hooks.  If you want to learn more about this specific storm track, read my post from this exact date last year.  So, while we may have fewer snowstorms, those that we do get may dump a lot of snow.  Hence the prediction that our average snowfall -- usually around 4 feet for the season -- may still materialize. 

So what about the February prediction?  Every El Nino computer model, and there are dozens, predicts a moderating of water temperatures as we go through the next 6 months or so...to the point where water temperatures return to near-normal by next May.  That moderation will make its greatest swing around February and March, which could lead to a more active weather pattern that feels more like a typical Wisconsin winter.  If Vegas had betting odds on this sort of thing, I'd put money down that February will be our most active weather month here in Wisconsin.  Thankfully, I'll be in Key West for the first half of it.

In the short term, look for higher than average temperatures and more rain events through December.  If it snows before Christmas, and it probably will, chances are good that temps warm enough to melt it.  Hence the brown Christmas.

That's my story, and I'm sticking to it.  Leave any questions in the comments.