Here is another topic I haven’t covered in my posts which covers the atmospheric movement of systems both zonal which we have seen much of this year and meridional which is a general air flow pattern from north to south, or from south to north, along the Earth’s longitude lines (perpendicular to a zonal flow). Extratropical cyclones in this environment tend to be stronger and move slower.
Atmospheric blocking is commonly referred to as the situation when the normal zonal flow is interrupted by strong and persistent meridional flow. The normal eastward progression of synoptic disturbances is obstructed leading to episodes of prolonged extreme weather conditions. On intraseasonal time scales the persistent weather extremes can last from several days up to a few weeks, often accompanied by significant temperature and precipitation anomalies. Examples of the 500 hPa height and anomaly fields associated with mature blocking episodes over the northeastern Atlantic and the North Pacific. These two regions are preferred areas for atmospheric blocking during the northern hemisphere cold season.
A common finding among scientific studies is that these long-lived weather extremes are associated with recurrent atmospheric flow anomalies. Numerous studies have found that the poor forecast skill beyond a few days results principally from the inability of numerical weather prediction models to simulate the onset and evolution of blocking flows.
In other words when the upper level winds are parallel or nearly parallel to the lines of latitude the wind pattern is termed zonal. When the winds cross the latitude lines at a sharp angle, the wind pattern is termed meridional. In a meridional pattern the jet stream will have highly amplified troughs and ridges. Low pressure systems tend to move faster (west to east) when associated with a zonal flow. A highly meridional flow can cause atmospheric blocking and spells of much below and much above normal temperatures. A meridional pattern, which its highly curved flow, generates more vorticity than that associated with a zonal flow. Forecasting becomes more challenging when the jet stream has a meridional pattern.
So, when you watch the news on TV at night the news generally deals with facts, however the weather deals with predictions and guesses when they go out more than a few days.
An Arctic front will bring cold temperatures and snow showers tonight and Wednesday. Slick roads and low visibility may make travel hazardous, especially for the Wednesday morning commute. Several inches of snow are possible near Lake Michigan, with lesser amounts inland. Single digit wind chill are also expected most of Wednesday. Warmer weather will arrive to end the week.
WINTER WEATHER ADVISORY IN EFFECT FROM 7 PM THIS EVENING TO NOON EST WEDNESDAY
* WHAT...Snow showers are expected this evening into Wednesday morning. Total snow accumulations of 1 to 3 inches are expected with locally higher amounts possible. The heaviest snow showers are expected to occur tonight. * WHERE...Portions of south central, southwest and west central Michigan. * WHEN...From 7 PM this evening to noon EST Wednesday. * IMPACTS...Plan on slippery road conditions with patchy blowing snow that could significantly reduce visibility. The hazardous conditions will impact the commute this evening and Wednesday morning. * ADDITIONAL DETAILS...Wind chills will drop into the -5 to 5 range Wednesday morning, with time to frostbite down to 20 to 30 minutes for exposed skin.
We are getting pounded with snow as we speak! The roads are getting very slippery! Great call for the wwa!
It gets cold in Otsego/Plainwell – very frigid today – photo taken today at Walgreens on M89 – photo by JD Chamberlain
https://michigan-weather-center.org/wp-content/uploads/2019/12/cold.jpg
And a new record low too
Slim
I took a pic over the weekend and sent it to family down south.
Wow lots of wishcasting by the snow lover crazies today I see. Meanwhile, it looks like a lock for another GREEN Christmas… and mild too!
Bring it! We keep getting cold and snow and certain people keep telling us how warm and dry it has been! Who would have thought?
https://www.weather.gov/images/erh/gis/LP_state_Snow.png
Not sure what there thinking but our furnace has been running since September yes it’s been outside …INDY
Not to put a damper on you thoughts but the NWS seems to have different ideas for next week and in fact it could get real warm before Christmas
“HAT SAME UPSTREAM PACIFIC SYSTEM WILL BUILD A DEEP TROUGH JUST
OFF SHORE OF OUR CONUS WEST COAST BY FRIDAY. THAT IN TURN RESULTS
IN UPSTREAM RIDGING SO UNTIL THAT UPSTREAM TROUGH GETS TO MICHIGAN
(AFTER CHRISTMAS) WE WILL HAVE SPLIT FLOW WITH POLAR JET IN
NORTHERN CANADA AND THE SOUTHERN STREAM SOUTH OF MICHIGAN. THAT
WILL LEAD TO AN EXTEND PERIOD OF DRY WEATHER. THE LAST SUCH EVENT
WAS IN 2010 WHEN BETWEEN THE 13TH AND THE 28TH WE HAD ONLY 3 DAYS
WITH MEASURABLE PRECIPITATION. MOST RECENT DECEMBERS IT’S HARD TO
GET 3 DAYS IN A ROW WITH NO PRECIPITATION. LIKELY WE WILL SEE
SOME DAYS WITH HIGHS INTO THE 50S NEXT WEEK.”
Looks like for any snow for Christmas it will take a trip well to the north,
Slim
Wow! That sounds just incredible! Shouldn’t be any travel delays this year!
Wait till the last few days of December! Then watch out and mark it down!
One more interesting note….we are coming up on 9 years since this area has had a blizzard warning. The last was the groundhog storm of 2011. That is a very long time for this area to have gone without one.
Another perfect setup where we get a little snow, then 2 days later it’s all melted again and the ground is bare. Been a great start this season with well below normal snowfall. This morning was perfect for stacking wood. Clear skies with a brilliant sunrise and perfect working temps.
Looks like a great day for snowshoeing or hiking! Get outside people and enjoy winter! Later.
I had to laugh at that. Snowshoeing on this?
https://www.flickr.com/photos/184860862@N07/49233353303/in/dateposted-public/
There is a little patch of snow in the lower right of the pic. Not sure the snowshoeing would be to great though.
Looking good by the last week of December and beyond! Bring it!
11-16 Day Outlook:
The forecast for this period still looks pretty good. Perhaps not as rosy as yesterday’s ideas, but ideas for the weather beyond Christmas still see some cooler air to return to all of the region. Starting in the NW first and finding it’s way into all of the region by later in the period. There are also indications that at least one winter storm could bring moderate to heavy snows to much of the Northwoods and possibly even into the central Midwest.
A high degree of caution is always needed in this time frame because it is so far out, but I am encouraged by the models not indicating the milder temps for the first half of next week to not lock in for the rest of the month.
Nice storm showing up around Christmas on the MODLES with some rain here but mostly snow to the north we have to watch that one being 8 days out things can change that would be great if it goes over snow for Christmas ..INDY
How many WWA’s have we had this year already? It seems like we have had at least 5 or 6. Keep em coming and let’s throw in about 10 WWW while we are at it!
Grand Rapids has had 3 snow events of one inch or more and I think there was one for some freezing mist. So I would say 4 or 5 but no WSW as of yet.
Slim
Let me describe the winter scenery and the slope conditions up in snow country from this past weekend!
Beautiful, gorgeous, fantastic, incredible, breathtaking, unbelievable, amazing, perfect, Heaven on Earth! How could anyone that lives in MI not love winter and cold and snow?
I am going to Boyne MT… in January so excited..Should be snowy cold …INDY
You know it and I will be heading up to Boyne many times this winter! Fantastic place!
Another winter day and yet another WWA on tap! The cold and snow is heading right towards West MI! Incredible!
Another winter day and another below normal temp day on tap!
Tommorow will be to …INDY
One of the biggest weather events of the year 2019 for Grand Rapids will be……
…RECORD FOR ANNUAL PRECIPITATION SET AT GRAND RAPIDS MI…
THE ANNUAL PRECIPITATION RECORD FOR GRAND RAPIDS, MI WAS BROKEN THIS
MORNING. TOTAL PRECIPITATION FOR 2019 NOW STANDS AT 48.81 INCHES.
THIS BREAKS THE OLD RECORD OF 48.80 INCHES SET IN 2008. THIS IS THE
MOST PRECIPITATION THAT HAS BEEN RECORDED IN A CALENDAR YEAR IN
GRAND RAPIDS SINCE RECORDS STARTED BEING KEPT IN 1892.
THE NEXT RECORD REPORT FOR ANNUAL PRECIPITATION FOR 2019 WILL BE
SENT AT THE END OF THE YEAR. PLEASE SEE THE DAILY CLIMATE REPORTS
FOR THE MOST RECENT TOTAL.
As of today December 17 the total for the year is at 48.82″
Slim
I believe it we can finally say 2019 was a wet summer not a hot summer every 3rd day we had rain keeping the heat away what a beautiful say ….2019 will also be one of the most stormy years booms ice and wind damages that I can remember in years let’s start 2020 with snow and cold why not?? INDY
Probably why GR had above normal snowfall last winter! This trend will continue into next year with tons of storms and snowfall!
While there is a chance of lake effect snow in the short range and a one day shot of cold. Most indications point to a mild (for December) period coming up over the weekend and Christmas week. And at this time the chances of a white Christmas here are on the low side.
Slim
Another Winter weather advisory for west Michigan noway?? I’m thinking 3-5 inches of snow in the advisory area is a good bet roads will become slippery overnight set your alarms early for the morning rush.Looking ahead MODLES showing some very cold air coming around new years Eve into January after a brief moderation next week…Let’s keep adding on INDY’S snow total great Scotty of a 107 berry inches for the Winter season let it snow let it snow …Have a good Tuesday set them alarms early for the morning drive..INDY
You know it Indy and yet all we hear is warm weather hype on here!