December 2021 Weather Discussion

[cloudy72]

Down to 28 IMBY this AM but up to freezing now.

[Bgoney]

32 and drizzle. Some record high temps will be threatened Thursday/Friday in the plains before the next cool down period.

[winterstormjoe]

Good Morning Les and Bgoney. Many of the new folks on here probably have not seen some of the weather discussions on here when folks have different outcomes in longer term forecasts. When this happens the discussions are wonderful as each person sees the outcomes in different ways and over the years when this happens it is usually about a 50/50 split which outcome is correct. First glad I mowed yesterday as the rain is falling at the moment. We knew the warm up is coming and everyone agreed on that part of the forecast. The weekend imo was going to be the change to the overall pattern and though I may be a day or so late I still believe that will happen. Why do I believe that is going to happen when some of the computer models and the tellies they throw out say otherwise. I look at the weather across the world and try to see where the pattern is and factors that will change a pattern. No doubt Alaska has been cold over the past month and that includes the entire state which is not always true with these cold outbreaks up there. Major storm coming in this weekend and this should send mild air across much of the state and temps should rise to normal or even above normal by next week. This in turns sends the current cold air further east across much of western and central Canada. Then we need a way to get that cold into the lower 48. This of course is usually done with a big storm or several storms that push the jet further south. I believe in the several storm outcome starting very early next week. Again if the tellies are correct then my forecast will not be accurate and once I see that the tellies are correct I will change the forecast but at the moment nothing has changed in my thinking. We have plenty of cold air on this side of the globe and just grabbing some of that cold can produce winter weather for us locally. First full week of winter starts next Monday and I use the 4-4-4 rule in winter weather around here. Four weeks where the pattern is terrible and winter weather is unlikely,four weeks where the pattern is great and winter weather is likely and the one we start out with next week where the pattern is good enough to produce winter weather and chances are more of a 50/50 chance. Again each winter is different and sometimes going by weeks is not easy but if you split the winter chances for us locally you get that 1/3 of the season for each item I mentioned before. No doubt I will be watching the weather over the world the next several days and this should either confirm my thoughts or tear them apart.

Good morning Tim, I watched Bgoney's time lapse of the cold intrusions in to AK and the larger intrusion that over takes the state around the 12th that moves east in to central Canada. While it shows that a big warmup is poised to hit the eastern third of the US with a SE ridge getting established and some lake cutters, I believe that a new pattern will develop after that with the OV being in a barometric zone with some of that cold air from Canada settling in the Midwest/plains. We'll start seeing a more TN/OV storm track with above precip. Now, what side of the zone will we be on when that change happens TBD. I believe this setup will become more noticeable after this weekend going in to next week.

[tpweather]

Hey Joe and hope all is well. I believe you made such a key point and that is where the barometric zone sets up. This November has been one of the calmest in terms of storminess for much of the nation that I can remember in sometime and this tells me that most likely December is going to be very stormy and to get that we need both the warm and cold air to get together and fight it out. Mother Nature is always balancing everything out so I tend to see how that may happen. Timing is always a key and believe most folks on here see the cold that is available but the timing of that to be released is probably the biggest difference folks are having with the extended.

[cloudy72]

Up to 35 here now and raining lightly.

[tron777]

I don't think we're that far apart Tim. The cold air is there, I just think the lows that could develop won't be strong enough to bring the colder air in for CVG land to give us anything substantial other than flurries/mix. Long ways out and like you , I won't care one bit to change my thoughts if need be.

I agree! None of us are truly that far apart with our thinking but on some guidance if the PNA is very negative, you're going to get a SE ridge response which means cutters for us. Rain to flurries, etc We need more ridging to build into the west Coast of North America and / or Alaska to get the colder air further SE. Just the way it is. We have no blocking up top anymore to assist us so changes in the Pacific are truly needed for a lot of wintry fun to develop. Like I said, I see one chance in that Dec 6-8th period then a warm period from 12/10 on. How long does that last remains to be seen. GFS says phase 7 by mid month. Euro delays it closer to Christmas due to the MJO looping back into 6 then going into 7. We wait...

[tron777]

Would love for this to be right - From Kyle MacRitchie's experimental MJO model:

realtimemjo.png

[cloudy72]

That would most definitely set us up for a rockin' January start if that materializes.

[tron777]

That would most definitely set us up for a rockin' January start if that materializes.

We'd have a shot around the Christmas to New Year's period also. But yeah, better after New Year's should Phase 8 occur.

[tpweather]

Would love for this to be right - From Kyle MacRitchie's experimental MJO model:


realtimemjo.png

Hey Les how accurate is Kyle's mjo model. I only follow it when you post on here. The current Aussie has us mid-way through phase 5 as of November 29th. Thanks

[tron777]

Would love for this to be right - From Kyle MacRitchie's experimental MJO model:


realtimemjo.png

Hey Les how accurate is Kyle's mjo model. I only follow it when you post on here. The current Aussie has us mid-way through phase 5 as of November 29th. Thanks

I have no idea Tim. I just use it as another tool. He's a bright guy though.

https://www.kylemacritchie.com/

The Aussie model having the MJO going into phase 8 by mid month, we also know is going to be wrong.

[tron777]

Looks like the 12Z GFS is going the Euro route with that Dec 6th - 8th chance ala a big wound up cutter.

[tron777]

12Z CMC has more of an unphased look so some light snow possible with that system.

[tron777]

0.04" here and at CVG for rainfall today.

[tron777]

12Z Euro coming in behind the Sunday system with a much stronger Canadian high so the cold air is able to pernitrate more into our area. This aspect is key to any wintry weather next week. Euro looking more CMC like now on this run as a result. Better cold push and a less phased system. It's the only way we're going to get snow next week out of this particular set up.

[tpweather]

Good afternoon and waited to see how the models are dealing with the weather next week. I talked earlier about how we can get the 4 weeks of a great pattern that usually produces winter weather for us. That is usually when we have an arctic air mass that drives well into the deep south central and gulf of mexico area. That is not what is happening next week. The 4 weeks to have say a 50/50 chances is when we have several storm systems with cold fronts that make their way through every couple of days. This tends to deliver rain at first but with each cold front the chances for winter like weather goes up. We need these fronts to arrive every few days so their is not a big enough warm up between systems.That is what I am seeing for next week. Of course you must have the cold air to grab with these fronts and I believe with each one more cold air will be available so chances go up as the week progresses. Their is much more that goes into getting winter weather and blocking is a huge part of that though models tend to have a hard time when that is going to happen so its a wait and see game much of the time. The good thing is that the normal storminess you tend to expect in the last two weeks of November will happen in the first two weeks of December. Will this turn into a cold and stormy end of December is what we need to look at next. So at the end of the day forecasters on here along with met's have different ways of coming to their final forecasts and many times when folks are at odds the middle road wins more often than not. On this forum Les and I agree quite often but their are times when we see different outcomes and that is the way we look at things with the forecasting tools we use. This is great for the forum and I know for myself it makes look at things from a different prospective. Does this make me change my way of forecasting and the answer is no but it also makes me look at other methods to see if those are working better in the current environment.

[tron777]

Hey Tim... the Euro run overall as a whole was colder then the GFS. It shows more of a coast to coast trough versus the GFS which has the trough out west and of course the SE ridge for us. Anyway for wintry weather to occur next week, we're going to need a stronger Canadian high to drop in behind our Sunday rain maker. Then we want the weaker system to follow it up while we have the cold air in place for snow. Those two things must be there or you get the GFS cutter solution for next week.

[cloudy72]

Rainfall so far today in my hood at 0.09" with another round coming in from eastern Indiana within the hour. This looks to stay mainly north of the river at this time.

[tpweather]

Hey Tim... the Euro run overall as a whole was colder then the GFS. It shows more of a coast to coast trough versus the GFS which has the trough out west and of course the SE ridge for us. Anyway for wintry weather to occur next week, we're going to need a stronger Canadian high to drop in behind our Sunday rain maker. Then we want the weaker system to follow it up while we have the cold air in place for snow. Those two things must be there or you get the GFS cutter solution for next week.

Exactly Les and we are on the same page on this part of the forecast. Just saw the NWS out of Fairbanks put out a special weather statement about a major winter storm for the western coast and western interior of Alaska late in the weekend and early next week. This is one of the points I made on how a pattern can change. Will watch the development of the storm but good to see that part of the forecast may come true.

[tron777]

Hey Tim... the Euro run overall as a whole was colder then the GFS. It shows more of a coast to coast trough versus the GFS which has the trough out west and of course the SE ridge for us. Anyway for wintry weather to occur next week, we're going to need a stronger Canadian high to drop in behind our Sunday rain maker. Then we want the weaker system to follow it up while we have the cold air in place for snow. Those two things must be there or you get the GFS cutter solution for next week.

Exactly Les and we are on the same page on this part of the forecast. Just saw the NWS out of Fairbanks put out a special weather statement about a major winter storm for the western coast and western interior of Alaska late in the weekend and early next week. This is one of the points I made on how a pattern can change. Will watch the development of the storm but good to see that part of the forecast may come true.

I saw that yesterday Tim from the Fairbanks office. AK has been off and running for wintry cold and weather over the past month. That looks to continue. The one thing though getting back to the models is that I noticed the EPO fold over ridge that helps us to even get a shot for snow next week... on the GFS it's gone just as quick as it came. However the Euro keeps it intact thus making it colder on its run for most of next week. So in short, we need to see changes in the Pacific for us to have shots at wintry weather. The Euro at least on this run has done that. Not ideal but gives us a chance nonetheless.

[tron777]

Rainfall so far today in my hood at 0.09" with another round coming in from eastern Indiana within the hour. This looks to stay mainly north of the river at this time.

Good, hope it stays north of here so I can get my leaves ground up for the last time. Just waiting until I completely kick this nasty cold I've had since Thanksgiving.

[tpweather]

Hey Tim... the Euro run overall as a whole was colder then the GFS. It shows more of a coast to coast trough versus the GFS which has the trough out west and of course the SE ridge for us. Anyway for wintry weather to occur next week, we're going to need a stronger Canadian high to drop in behind our Sunday rain maker. Then we want the weaker system to follow it up while we have the cold air in place for snow. Those two things must be there or you get the GFS cutter solution for next week.

Exactly Les and we are on the same page on this part of the forecast. Just saw the NWS out of Fairbanks put out a special weather statement about a major winter storm for the western coast and western interior of Alaska late in the weekend and early next week. This is one of the points I made on how a pattern can change. Will watch the development of the storm but good to see that part of the forecast may come true.

I saw that yesterday Tim from the Fairbanks office. AK has been off and running for wintry cold and weather over the past month. That looks to continue. The one thing though getting back to the models is that I noticed the EPO fold over ridge that helps us to even get a shot for snow next week... on the GFS it's gone just as quick as it came. However the Euro keeps it intact thus making it colder on its run for most of next week. So in short, we need to see changes in the Pacific for us to have shots at wintry weather. The Euro at least on this run has done that. Not ideal but gives us a chance nonetheless.

Thanks Les and did not see the info from the Fairbanks office until today but have seen the storm for several days and one that looked to be impressive.

[tron777]

12Z EPS is showing more of a broader trough next week too. Interesting. So we've got the GFS and GEFS showing more of a -PNA pattern with the foreign models showing more of a broader trough across the northern half of the country. Let the games begin!

[cloudy72]

Latest batch moved through and up to 0.14" now.

[tron777]

Glad to see that it's missing us, Mike.