My interpretation of the polar vortex this year.

There's a constant low pressure over the Hudson Bay that has been there for a long time. There's a blocking pattern off the coast of the southeastern US. There's also blocking pattern off the coast of the northwestern US. Add in sudden stratospheric warming in the north pole and this is what we get:

The rule of thumb is: If it's cold in Alaska, it's gonna be warm in Indiana. If it's warn in Alaska, it's gonna be cold in Indiana.

An excellent blog post by Amy Butler and Laura Ciastro on this season's polar vortex.

Sudden Stratospheric Warming is a complex topic. If you are interested in the details, you can read the full blog post here:

https://www.climate.gov/news-features/blogs/polar-vortex/polar-vortex-causing-us-cold-air-outbreak

Otherwise, here are the most important info-graphics from the post:

Wild temperatures wings coming.

Tuesday night's low will be -2 degrees.

Friday's high temperature will be 43 degrees with rain. Boooo!

Next Tuesday's high will be 10 degrees and the low will be -7 degrees.

Watch out for a big snowstorm during the last week of January, specifically between January 26-29.

The data for February is showing mixed results. Some of the data says warm and some of the data says cold.

I see it on the radar so where is the snow?

The cold dense dry air is evaporating the snow before it hits the ground. Had we not had -2 degrees Thursday morning, it might be snowing now. Nonetheless, that is why you se a full radar screen and no snow outside your window. So all those 4-6 inch totals you saw yesterday are not going to happen. Expect 2-3 inches. 

Southern states will be closed until further notice.

 

Sometimes the best cure for ice is more snow.

Compacted snow + snowmelt = Ice

The snow should stick around for a while because it will be cold for a long time. One problem that we have is the very gradual and slow snowmelt that occurs when the sun is out and then later on, that water refreezes overnight and turns into black ice. If temperatures are going to stay cold then more snow is better because it creates traction on top of the ice and it keeps people from falling and crashing like saw a Kroger this evening. Look at this sheet of ice in the parking lot:

1-5-25 Snowstorm pictures from Bloomington Indiana.

These pictures are from the Sunday (1/5) to Monday (1/6) snowstorm event in Bloomington Indiana.

 

Snow and Ice for Mexico on January 23 & 24th.

I don't buy it but this is what the GFS model is spitting out.

Snow for Indiana this weekend plus other important updates.

It's going to be very cold tonight. The National Weather Service is forecasting a low temperature of 0 degrees tonight. I think it will get lower than that because of clearing skies. I think the low temperature will be -2 degrees. 

The storm system that is bringing big snow and ice to the south will also spread light snow into Indiana due to the merging of two storm systems over eastern Kentucky. 

We seem to be in a pattern where we will see a storm system every weekend from now through January 25th. 

The polar vortex will relax for three days before it reloads again. We should be above freezing from January 15 -17. After that, it gets cold again. 

After that, the polar vortex eases again during the first week of February. There are hints that it will try and make a comeback by Valentines Day.

I don't like it but the National Weather Service has removed the "Windchill Advisory" and replaced it with a "Cold Weather Advisory". I think phrase "cold weather advisory" is fairly relative. I think the phrase "windchill advisory" automatically informs people to bundle up and wear extra layers and not to stay outside too long. That's just me though. In addition to that, the NWS has changed a lot of their definitions. If you would like to see all of them, you see them  at:
https://www.weather.gov/lwx/warningsdefined

Here is an example of the new "Cold Weather Advisory"

Cold Weather Advisory

URGENT - WEATHER MESSAGE
National Weather Service Louisville KY
1158 AM EST Wed Jan 8 2025

INZ076>079-083-084-089>092-KYZ023-025-030>037-040>043-049-090515-
/O.NEW.KLMK.CW.Y.0001.250109T0400Z-250109T1500Z/
Orange-Washington IN-Scott IN-Jefferson IN-Dubois-Crawford-Perry-
Harrison IN-Floyd-Clark IN-Hancock-Meade-Jefferson-Oldham-Trimble-
Henry-Shelby-Franklin-Scott KY-Harrison KY-Woodford-Fayette-
Bourbon-Nicholas-Clark KY-
Including the cities of Brandenburg, Corydon, Paris, Salem,
Cynthiana, Lexington, Georgetown, Louisville, New Castle,
Scottsburg, Tell City, Madison, Jasper, Hawesville, Winchester,
Paoli, La Grange, Frankfort, New Albany, Jeffersonville, English,
Bedford, Versailles, Lewisport, Milton, Shelbyville, and Carlisle
1158 AM EST Wed Jan 8 2025 /1058 AM CST Wed Jan 8 2025/

...COLD WEATHER ADVISORY IN EFFECT FROM 11 PM EST /10 PM CST/ THIS
EVENING TO 10 AM EST /9 AM CST/ THURSDAY...

* WHAT...Very cold wind chills or air temperatures as low as 5 below
  zero expected.

* WHERE...Portions of south central Indiana and east central, north
  central, and northwest Kentucky.

* WHEN...From 11 PM EST /10 PM CST/ this evening to 10 AM EST /9 AM
  CST/ Thursday.

* IMPACTS...Frostbite and hypothermia will occur if unprotected skin
  is exposed to these temperatures.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Use caution while traveling outside. Wear appropriate clothing, a
hat, and gloves.

Keep pets indoors as much as possible. Make sure outdoor animals
have a warm, dry shelter, food, and unfrozen water.

Seven inches of snow in Atlanta Georgia? Big snow in the south for Friday, January 10, 2025

I bet this is exciting for people in the south. Winter Storm Watches are posted for Louisiana, Kentucky, Tennessee, Mississippi, Alabama and Georgia. Atlanta is forecast to get anywhere from 1 to 7 inches of snow. That will be an absolute paralysis of the city. If you have family members in the south, contact them and tell them to prepare now.

Ignore social media posts about the winter storm.

Tune in to the Weather Channel and check out what the National Weather Service is saying. Ignore the socials!