December 2023 Weather Discussion

[tpweather]

Good Morning Les and wonderful forecast. I agree with almost everything except timing of a new pattern. What happens quite often with the models is they are to quick to change a pattern especially the gfs. Then they go to far the over way and it becomes to slow. We never fell for the to quick changeover on this forum. I still like the 21st and would expect some bigger storm to usher in the change. I will watch over the next several days and see if that bigger storm comes onshore in central or southern California. If that starts to show up over the next 3-5 days on the extended model I will feel much better about the 21st. Could this be delayed and sure nothing is a sure bet when it comes to the weather.

Funny earlier this week the models showed both the NAO and AO negative or maybe neutral this weekend and that quickly changed to positive. That is why I kept mentioning that imo those two were going to be more positive than the models showed just earlier this week. Models are great but the pattern is what drives the models but the problem is the models sometimes gets bad input and once they get the correct input you see a big change.

Yes we will see winter weather this season and to what extent is still very debatable. I still believe the east coast gets slammed and we get some of the leftovers which sometimes is not bad plus I still expect a couple bigger storms to move in here and that really was why I went high on snow totals. El Nino's normally produce a few big storms during the winter especially after it has peaked. I believe we are at the peak now so that is why 10 days or so from today I expect a more impactful storm to hit the USA.

[Trevor]

I don’t really see much in the way of cold or snow this month to be honest. I had nearly a nearly snowless forecast for Dec (1” for the month). I think we see some cool snaps behind fronts but nothing too cold. I expect snow and especially ice chances to increase in January. But yeah as for Dec I’m not really seeing much noteworthy.

Edit: I think any formidable pattern changes hold off until January.

[Bgoney]

No changes in forecast , that still means a SZW is in effect for parts of the region.

[Trevor]

No changes in forecast , that still means a SZW is in effect for parts of the region.

Yeah west of 71 looks iffy. Forecast confidence is of course higher for the east side.

[tpweather]

Just to add some to my post earlier. Watch over the 5 days or so and see if the cold in Alaska starts invading western Canada. This tells me the PV is moving and will that end up also a disruption as well or a SSW event. Will watch this and again the temps forecast in Russia and still not seeing any signs that the cold air over there will be getting colder which would no doubt give us a much warmer end of December. The past 2 weeks has been a nice rebound in Siberia in terms of cold and part of that was a late start to the snowy season which happened in mid-late November. Dr.Cohen has his theory's and I just never understand them and maybe I am just to dumb to figure what he is talking about with snow cover in Siberia. He hits about 50p/c of the time which is probably what most long term met's or folks involved with the weather end up doing.

The folks on here do a great job and I believe one reason this forum is really good and that is the many different ways folks make forecasts. Sure we all have a bias and sometimes that can hinder your thought process but gathering info from everyone is imo the best way to forecast because there are so many great ideas and I know by reading the posts from folks here I pick up things that I miss in my own forecast.

[Trevor]

First time back in front of the green screen in at least ten years! We're back, baby!

[Bgoney]

First week under our belts and a temp mean of + 4 of normal , back in the day I would have considered that a torch but currently I’ll give it a slightly above normal. Don’t see any changes in long term ( 2 weeks) , 500mb pattern remains hostile for the lower 48 and southern Canada for significant snowfall (other than higher elevation and lakes areas. Such a long way to go for changes into arctic air let alone polar air masses. We’ve seen and talked about these Aleutian/GOA patterns many times before and they can be hard to break down, much like a stout SE ridge can be ( if another one can ever form) . Those west coast ridges that periodically show up in modeling into southern Canada only tap into stale cold , mostly PAC air that then goes over snowless or minor snow depth real estate. Need to see massive and quick changes for the holiday season by the end of week 3 (21st) … Whoo, I’m out of breath, that’s a long post for me!!

[Bgoney]

Possible upgrade to warning status for current SZW(50%) and a possible additional SZW to be issued (40%)to the S/E of 71 in our local area. Waiting on the rest of 12z data

[Trevor]

Possible upgrade to warning status for current SZW(50%) and a possible additional SZW to be issued (40%)to the S/E of 71 in our local area. Waiting on the rest of 12z data

HRRR and NAM would agree.

[Angelika]

What is SZW?

[Bgoney]

What is SZW?

Screw-Zone Watch. I know , it’s sophomoric.

[MVWxObserver]

What is SZW?

Screw-Zone Watch. I know , it’s sophomoric.

No wonder I couldn't find that particular abbreviation in some of the online wx glossaries.

[Bgoney]

What is SZW?

Screw-Zone Watch. I know , it’s sophomoric.

No wonder I couldn't find that particular abbreviation in some of the online wx glossaries.

lol, Eric. Just trying to jazz up our bluesey of a weather pattern. You should see my own personal WX glossary I have , it’s a doozy

[tron777]

Good Morning Les and wonderful forecast. I agree with almost everything except timing of a new pattern. What happens quite often with the models is they are to quick to change a pattern especially the gfs. Then they go to far the over way and it becomes to slow. We never fell for the to quick changeover on this forum. I still like the 21st and would expect some bigger storm to usher in the change. I will watch over the next several days and see if that bigger storm comes onshore in central or southern California. If that starts to show up over the next 3-5 days on the extended model I will feel much better about the 21st. Could this be delayed and sure nothing is a sure bet when it comes to the weather.

Funny earlier this week the models showed both the NAO and AO negative or maybe neutral this weekend and that quickly changed to positive. That is why I kept mentioning that imo those two were going to be more positive than the models showed just earlier this week. Models are great but the pattern is what drives the models but the problem is the models sometimes gets bad input and once they get the correct input you see a big change.

Yes we will see winter weather this season and to what extent is still very debatable. I still believe the east coast gets slammed and we get some of the leftovers which sometimes is not bad plus I still expect a couple bigger storms to move in here and that really was why I went high on snow totals. El Nino's normally produce a few big storms during the winter especially after it has peaked. I believe we are at the peak now so that is why 10 days or so from today I expect a more impactful storm to hit the USA.

Tim, if the pattern is going to change this month, I don't see it happening any earlier then Christmas. I am still hopeful for the last week of the month. All the same, don't be surprised if what Trev posted turns out to be correct, meaning we have to wait until after the New Year.

[tron777]

Possible upgrade to warning status for current SZW(50%) and a possible additional SZW to be issued (40%)to the S/E of 71 in our local area. Waiting on the rest of 12z data

HRRR and NAM would agree.

12Z GFS "jackpots" the river counties with screw zones on either side.

[Bgoney]

Possible upgrade to warning status for current SZW(50%) and a possible additional SZW to be issued (40%)to the S/E of 71 in our local area. Waiting on the rest of 12z data

HRRR and NAM would agree.

12Z GFS "jackpots" the river counties with screw zones on either side.

It shows a continuation of the weaker trend imo, later development of low equals a faster front moving away. Amounts to our south/SW continue to lessen also

[tpweather]

Good Afternoon and another system imo that keeps the trend going which is the models are too bullish on rainfall in our area and these systems do well on the east coast. I still have .5-1.0 locally. Until this trend breaks I am going to continue on the lower side of totals. At the end of the day where does this system gain strength and if its southwest of us then yes higher totals but if that happens near us or even east of us then totals will be lower.

Les you know me I have seen these kind of pattern change overnight so until I see a clear sign that the cold is delayed I will stay with my current thoughts.

[Bgoney]

61 and sunshine here in Indian hill

[Bgoney]

IMG_0974.jpeg

[tpweather]

61 here as well though we had a nice cloud cover roll in but the sun is shining once again.

[Trevor]

18z NAM and HRRR juice things back up a bit, and actually re-introduce some ingredients for strong storms. STP and supercell composite are elevated. Showing more in the way of CAPE as well. Interesting…

[Trevor]

Marginal comes up to our southern posters. Will need to see if 00z and 06z high-res models continue this. If so, that risk area may need to be nudged north a bit.

[tron777]

60 currently, 62 for my high today.

[tpweather]

Good Afternoon and 60 was nice though still a tad on the windy side at times. Where will the cutoff be later Saturday in terms of the heavier rain. Most folks could use some rainfall and everyone should get some but locally still going with .5-1.0. The cutoff could be so tight and even in the local area where somebody gets .25 in the northwest part of the area and 1.25 in the southeast. We will see where this sets up later Saturday.

Concerning the longer term and really when will the pattern change. The Nao is a factor before Christmas and if this changes say in the 18-21st period this helps. Another thing I will be looking at is in the pacific. If a storm is southwest of Alaska later next week into the following week how strong will this be and is it one storm or several. Do we get one big storm that comes up through Alaska and then sends the cold that will be in Alaska eastward towards the Yukon. Then if those items happen you can get the PV to become elongated over east central Canada and that can push down cold air into the eastern half of the USA by the 21st. This is the way I see the changeover before Christmas. I know the models will show the fast winds in the pacific that floods the USA and sure that can happen but if the storm is either weaker southwest of Alaska or has moved away this should allow ridging to grab hold to a certain extent and really slow down the winds.

Les and I are not on the same page with this and it happens several times during the year and not always but it seems the truth is somewhere between both forecasts. When we are on the same page I feel more confident of course and really this is more about the timing then what the end result will end up being.

[Bgoney]

IMG_0976.jpeg