January 2024 Weather Discussion

[tpweather]

So yes the mjo is in phase 4 or 5 so why the cold and snow. The mjo at this time is not the main factor but the very negative AO and NAO. Those two heading back to neutral and then positive the mjo will be more controlling imo. Then will we continue to head towards phases 6 and 7. To early on those but hopefully later this month we see at least a neutral AO and NAO come back and then back to negative. Hopefully next month if the cold returns we see more systems come into southern California and this could help in getting the STJ a little further north than we saw in December.

[tron777]

I think we get a week and a half to 2 week break as the pattern reloads. Again, over the weekend I'll have more time to dive into the longer term.

[Bgoney]

The +NAO/AO combo really flushes out the Arctic air in southern CANada and lower 48 , another incoming jet extension to the west coast to boot

[tpweather]

The +NAO/AO combo really flushes out the Arctic air in southern CANada and lower 48 , another incoming jet extension to the west coast to boot

I agree and the one difference this time is the coldest of air will not retreat back to Siberia and eastern Europe but will try and reside in Alaska and western Canada. So hopefully once we get the pattern to switch again we are not waiting on the cross polar part of the equation at first. We probably don't get out of hand with warmth because we have the STJ to the south that is going to be on the move again and though we can get quite wet the jet is fast enough that a strong southeast has a hard time getting established.

[tpweather]

Concerning late Monday and early Tuesday. Still a concern on the fr/rain and models will probably start to see better signs of this as we get closer. Hard to move cold dense air from the surface and seen many of these systems that really cause problems. Even once you get air temps above 32 it can take another day to really get the cold air completely out of the way. Will watch this closely this weekend but expect some problems in that time period

[tron777]

The +NAO/AO combo really flushes out the Arctic air in southern CANada and lower 48 , another incoming jet extension to the west coast to boot

Yep. We've lost the nice look on the Ensembles for late this month into early Feb. We may need to wait a bit longer then I had originally thought. MJO is cruising though so the sooner it gets thru the warmer phases the better.

[tron777]

Concerning late Monday and early Tuesday. Still a concern on the fr/rain and models will probably start to see better signs of this as we get closer. Hard to move cold dense air from the surface and seen many of these systems that really cause problems. Even once you get air temps above 32 it can take another day to really get the cold air completely out of the way. Will watch this closely this weekend but expect some problems in that time period

I agree with this, esp. now since we have a snowpack. We didn't before so we'll see if the models adjust in time. It will also depend on the moisture feed. If the moisture stays west of us long enough before moving in, with a strong LLJ, we could warm up just in time to avoid issues. Something to watch for sure by early Tues morning of next week.

[MVWxObserver]

Both CVG / DAY got to 25 and CMH 26 today at midnight.

[tron777]

26 here and that was my high for the day which occurred at midnight.

[tron777]

Day 10 so it probably won't happen but the 18Z GFS and 12Z Euro were trying to cook up a little something.

[Bgoney]

Complete flip and about as ugly as you can get at 500mb

IMG_1224.png

[Trevor]

Concerning late Monday and early Tuesday. Still a concern on the fr/rain and models will probably start to see better signs of this as we get closer. Hard to move cold dense air from the surface and seen many of these systems that really cause problems. Even once you get air temps above 32 it can take another day to really get the cold air completely out of the way. Will watch this closely this weekend but expect some problems in that time period

I agree with this, esp. now since we have a snowpack. We didn't before so we'll see if the models adjust in time. It will also depend on the moisture feed. If the moisture stays west of us long enough before moving in, with a strong LLJ, we could warm up just in time to avoid issues. Something to watch for sure by early Tues morning of next week.

Yeah Tim I have been addressing the ZR concern for a few days now on my page. Watching it for sure.

[tron777]

1 degree for the low at CVG, back up to 2 now. 2 degrees also IMBY. We will go below zero tonight!

[MVWxObserver]

Currently at 1 degree here and G'ville and progged for around 18 today.

3 above for tonight / Sun morning!

[tpweather]

Good morning and yes another dusting overnight. My guess is somewhere between 3.5 and 4 is where I ended up. Enjoy the snow because by Wednesday much of it will be gone. Les you are correct if the moisture return takes longer then the frz/rain chances are slimmer. It just always seems to catch the models sleeping and really to make folks aware that late Monday into Tuesday that chance is there. This is not a ice event that shuts down everything and really more like a 4-6 hour period if the moisture arrives then some glazing is very possible and probably more important will be sidewalks and places that get less sunshine

[tpweather]

Alaska getting really cold with temps in the -20 - -30 range and by midweek expecting -50 - -60 and sure some places colder.When it gets that cold in Alaska usually we get quite mild. Still having the cold on this side of the globe helps in getting the cold back here in a few weeks.

[Bgoney]

Good morning and yes another dusting overnight. My guess is somewhere between 3.5 and 4 is where I ended up. Enjoy the snow because by Wednesday much of it will be gone. Les you are correct if the moisture return takes longer then the frz/rain chances are slimmer. It just always seems to catch the models sleeping and really to make folks aware that late Monday into Tuesday that chance is there. This is not a ice event that shuts down everything and really more like a 4-6 hour period if the moisture arrives then some glazing is very possible and probably more important will be sidewalks and places that get less sunshine

Yea these are the type of events that can be worse than 3 or 4 “ of snow as far as catching people off guard. Temps could be in the 40s but those ground temps will take a long time to get above freezing especially where roads are sheltered from getting previous days sunshine

[tpweather]

Tonight will probably be the coldest night of the winter and I have -4 - -8. Of course there will be some normally colder rural areas the can see -10 - -15.

[Bgoney]

Don’t like 12z NAM at all with the moisture arriving right around rush hour Tuesday

[Trevor]

Michigan City
@Les you really need to relocate to the LES belts!!

[tpweather]

Besides the chances of some frz/rain early in the week the next item is heavy rainfall. Trying to figure where the strong highs are located next week and best chances for systems to travel. This could change somewhat but it looks like the heaviest of rains fall to our southeast and eastern Kentucky and Tn has plenty of snow on the ground plus you are dealing with the mountains. Those rivers in the valleys have houses that are usually really close to the rivers and creeks and get flooded quite often. The one good thing is further upstream though we have snow on the ground the thaw may be a little slower which helps because you don't want a ton of moisture upstream to enhance the flooding. Locally we will see the normal spots that get some flooding but at the moment don't believe its a major issue unless the heaviest rains end up on top of us.

[tron777]

Trev.... there was over 30"+ on the north side of LaPorte, IN.

Tim / Bgoney... definitely something to watch for the Tues morning commute for sure with regards to some light frz rain being possible. How much QPF do we see before the surface temps rise above freezing and ground / road temps will be critical in getting the forecast correct. The snowpack is going to help in keeping the ground frozen longer as well as keeping surface temps cooler for a longer period of time. These are things that the models won't be picking up on very much.

The NAM is certainly much faster at getting the moisture in here then the GFS is by several hours. The timing of the moisture's arrival is key to see how bad things can get. I also think that the moisture at first will be light which is also better for ice accretion versus if it was heavier. 12Z RGEM is like the NAM showing the moisture arriving earlier. Not good. The RGEM has like 4 or 5 hours of frz rain and this would be WWA criteria should this pan out.

zr_acc-imp.us_ov.png

[tpweather]

Great Post Les and this is where a forum like this is important. Met's on TV are so limited at times and they get late to the dance.

[tron777]

12Z CMC showing a touch of frz rain as well to begin Tues morning. It'll be interesting to see what the more hi res models show once we get closer. Even the 9Z SREF, if you look at precip type POP is showing some frz rain too.

[tpweather]

12Z CMC showing a touch of frz rain as well to begin Tues morning. It'll be interesting to see what the more hi res models show once we get closer. Even the 9Z SREF, if you look at precip type POP is showing some frz rain too.

I believe the closer we get to the event the more frz/rain will show up. If we were the southern end of the snow pack that is one thing but the snow pack is still in Tn so the warming uses up some energy to melt the snow but hard to get the colder air at the ground to move quickly. We are not trying to scare anybody at all but is more a heads up late Monday and early Tuesday travel and walking could be a little on the dicey side for several hours. Yes during the day it will turn to mainly rain but still need to watch any area that gets little sunshine because with temps going well below zero tonight the road temps are going to take a period of time before they reach above 32