Absolute Vorticity

tpweather wrote: ↑Fri Jan 20, 2023 6:55 pm

tron777 wrote: ↑Fri Jan 20, 2023 6:39 pm

tpweather wrote: ↑Fri Jan 20, 2023 5:55 pm

tron777 wrote: ↑Fri Jan 20, 2023 4:47 pm 18Z GFS looks a little better then 12z for Sunday. We are on the fence though in CVG Land. I think what we are seeing on some of the mesoscale models and short term models is the precip rate is heavier so better snow chances versus seeing an all rain event. Since the GFS is a global model, like the CMC and Euro, they sometimes cannot see those kinds of details.

Good Evening Les and finally went over the models and see if there is anything that stands out for the first system. No doubt it looks like we will be near the rain/snow line though I expect most folks to start out as snow and then we see where that line sets up. Since we don't have a big push of warm air once the line gets going it will probably stay there most of the time. I can see a 1-2 inch snow for many folks but if you are in the area that switches over it will be gone by noon or so. The nam when I looked at it earlier today seemed to be going that way and it makes sense.

Hey Tim! I'm ready to talk weather for a while this evening and if the precip rate is heavy enough, then we may see a situation where it is mainly snow then as it lightens up, you go over to a light drizzle or something to that effect. Either way as I've been saying with marginal temps, we need heavy precip rates to achieve a mainly snow scenario. It'll be a wet snow with those big silver dollar type of flakes should the precip rate that we are seeing on some guidance be heavy enough.

Exactly Les and the precip rate is key Sunday morning. I can see where its snowing and then the rate goes down at the end which leads to a lovely drizzle like you mentioned. Being on the fence though imo gives you a better shot of a little higher precip total so you must take a little risk to get a reward.

The mid-week system is still at least a day and maybe 2 before its set in stone. Can we get a decent snow and sure we can but also we could end up with mainly a rain maker with front and back end snow that really is not much to talk about. I do believe no matter what happens a really decent shot of cold air comes in later next week and the weekend and most likely a few clippers should help bring the colder air in. The best pattern we have seen this year so anything will get you excited. Still watching the PV and lets see this how that works out next month for any effects we may get.

I agree. High Risk, High reward pattern that you've seen me post many times lately. You have to smell the rain sometimes to get the snow and Sunday may turn out to be one of those situations where a slushy inch or two may occur. We'll see!! Then for mid week, I really like the idea of snow to rain to snow as I mentioned earlier. Most of the data I have seen shows that scenario occurring.

After that system, we should have a window of NW Flow for clippers as you said. How long that pattern lasts is TBD. Then we warm up. Second half of Feb and March may prove to be interesting if things break right in terms of the PV and any potential SSW effects. If this breaks the right way, March could be a wintry month for sure with a delayed spring likely. It is too early to know that from this distance so it is just speculation at this time. We are in pretty good agreement with our thoughts as we usually are.

18Z Euro is a bit north / stronger for Sunday's system versus the 12Z run. Not much change really to cause me to change my current thoughts.

Les looking forward to the next 10 days for sure and then lets see where the chips may fall. The mjo which has been a mess or maybe just the models but if the current forecast is keeping it in phase 2 and 3 then that bodes well in February. I believe the PV will be disrupted but just not sure how much and if we get the elongated version which can work but you better be in the correct place of a true split and it heads towards southern Ontario which is just about a perfect spot for us. Again barely halfway through met winter so the odds are in our favor to have more chances for winter weather the second half.

tpweather wrote: ↑Fri Jan 20, 2023 7:20 pm Les looking forward to the next 10 days for sure and then lets see where the chips may fall. The mjo which has been a mess or maybe just the models but if the current forecast is keeping it in phase 2 and 3 then that bodes well in February. I believe the PV will be disrupted but just not sure how much and if we get the elongated version which can work but you better be in the correct place of a true split and it heads towards southern Ontario which is just about a perfect spot for us. Again barely halfway through met winter so the odds are in our favor to have more chances for winter weather the second half.

I'm not trusting the MJO forecasts at all. It should already be out in Phase 2 per a lot of the models, yet the last time I checked it from the Aussies as of 1/18 it's still in the neutral circle. The modeling shows Phase 2, 3 then it goes back into the circle again with the potential to re-emerge into 7, 8 by mid February. How many times have we seen this before? The MJO has had such a hard time getting into the colder phases of 8, 1 and 2 due to the things Bgoney has been talking about all winter long. He's been spot on too. The modeling has been terrible so I'll believe the MJO when I see it. That is honestly how I feel about it.

CB has his first call map out for Sunday's system:

tron777 wrote: ↑Fri Jan 20, 2023 7:28 pm CB has his first call map out for Sunday's system:


Chris-Special-2.png

Not a bad first call imo.

tpweather wrote: ↑Fri Jan 20, 2023 7:30 pm

tron777 wrote: ↑Fri Jan 20, 2023 7:28 pm CB has his first call map out for Sunday's system:


Chris-Special-2.png

Not a bad first call imo.

It fits the NAM, RGEM, and HRRR models nicely. If those short term models are correct, it'll be a nice day for us snow lovers for a few hours on Sunday.

The 21Z RAP isn't as cold as the 15Z run was for Sunday, but it has the rain / snow line over our SE counties and keeps the Metro counties of NKY and points north in the all snow zone. If we can manage to pull this off due to heavy precip rates, then 1-2" of slushy snow on the grass / car tops is doable.

tron777 wrote: ↑Fri Jan 20, 2023 7:43 pm The 21Z RAP isn't as cold as the 15Z run was for Sunday, but it has the rain / snow line over our SE counties and keeps the Metro counties of NKY and points north in the all snow zone. If we can manage to pull this off due to heavy precip rates, then 1-2" of slushy snow on the grass / car tops is doable.

I will take it plus I wont need to shovel but that is a chore I really love though.

tpweather wrote: ↑Fri Jan 20, 2023 7:46 pm

tron777 wrote: ↑Fri Jan 20, 2023 7:43 pm The 21Z RAP isn't as cold as the 15Z run was for Sunday, but it has the rain / snow line over our SE counties and keeps the Metro counties of NKY and points north in the all snow zone. If we can manage to pull this off due to heavy precip rates, then 1-2" of slushy snow on the grass / car tops is doable.

I will take it plus I wont need to shovel but that is a chore I really love though.

Yeah... probably won't need the shovel with this one, agreed.

I'm waiting for the 0Z HRRR to come in for Sunday... in the meantime, radar tonight shows mountain snow / valley rain in Eastern CO and NM (northern piece) with moisture return from the Gulf creating rain down in TX, LA, and MS (southern piece). How these two areas interact will help determine our outcome for Sunday's system.

I'm also thinking about tomorrow's high temps too. There is a chance that the sunshine I talked about this morning may have a tough time occurring due to an inversion keeping the low clouds trapped. If this happens, temps may not hit 40+ as I had originally called for. Then, even if we do see a period of clear skies, that won't last long Sat night due to increasing clouds ahead of Sunday's system. We need to watch our temps very closely for tomorrow and tomorrow night. I know it may sound like I am grasping at straws here (and I probably am LOL) but these minor little details every once and a while can make a difference in the outcome for this next system.

tron777 wrote: ↑Fri Jan 20, 2023 8:22 pm I'm also thinking about tomorrow's high temps too. There is a chance that the sunshine I talked about this morning may have a tough time occurring due to an inversion keeping the low clouds trapped. If this happens, temps may not hit 40+ as I had originally called for. Then, even if we do see a period of clear skies, that won't last long Sat night due to increasing clouds ahead of Sunday's system. We need to watch our temps very closely for tomorrow and tomorrow night. I know it may sound like I am grasping at straws here (and I probably am LOL) but these minor little details every once and a while can make a difference in the outcome for this next system.

I agree Les and with a few days of temps cold once again and being mid-January the roads could become slick.

tpweather wrote: ↑Fri Jan 20, 2023 8:27 pm

tron777 wrote: ↑Fri Jan 20, 2023 8:22 pm I'm also thinking about tomorrow's high temps too. There is a chance that the sunshine I talked about this morning may have a tough time occurring due to an inversion keeping the low clouds trapped. If this happens, temps may not hit 40+ as I had originally called for. Then, even if we do see a period of clear skies, that won't last long Sat night due to increasing clouds ahead of Sunday's system. We need to watch our temps very closely for tomorrow and tomorrow night. I know it may sound like I am grasping at straws here (and I probably am LOL) but these minor little details every once and a while can make a difference in the outcome for this next system.

I agree Les and with a few days of temps cold once again and being mid-January the roads could become slick.

If the precip rate is heavy enough, I could see that happening for a few hours. So far, the 0Z HRRR looks a little stronger vs the 18Z run. It's out to 32 hours (out of 48). Kind of interested to see how this run finishes. I'll post more shortly once it's done.

Oh yeah, def stronger! Thermals are a little warmer as a result but with the rain / mix line just south of Boone, Kenton, and Campbell co's, if this is right... we might be in a good spot in the Cincy Metro area here. Gonna be close and a nail biter! But these set up's usually are. Like I said, if the snowfall rate is heavy enough, we can overcome the marginal thermal profile and surface temps. This might be an interesting system here. It's going to probably cause me to stay up for the 0Z NAM now.

tron777 wrote: ↑Fri Jan 20, 2023 8:44 pm Oh yeah, def stronger! Thermals are a little warmer as a result but with the rain / mix line just south of Boone, Kenton, and Campbell co's, if this is right... we might be in a good spot in the Cincy Metro area here. Gonna be close and a nail biter! But these set up's usually are. Like I said, if the snowfall rate is heavy enough, we can overcome the marginal thermal profile and surface temps. This might be an interesting system here. It's going to probably cause me to stay up for the 0Z NAM now.

Same here Les and then heading to bed

LOL! The 0Z HRRR is def a weenie run for the Metro. Basically it starts snowing at 8am Sunday, and it finally starts to wind down after 4pm. Still only a couple of inches per snow depth maps but just to see it snowing for 8 hours??? I sure wasn't expecting any model to show something like this. Is it real or just model BS? I said earlier that the HRRR hasn't done very well this winter, so def take it with a grain of salt. Would like to see the NAM, RGEM, etc showing this before going overboard.

tpweather wrote: ↑Fri Jan 20, 2023 8:51 pm

tron777 wrote: ↑Fri Jan 20, 2023 8:44 pm Oh yeah, def stronger! Thermals are a little warmer as a result but with the rain / mix line just south of Boone, Kenton, and Campbell co's, if this is right... we might be in a good spot in the Cincy Metro area here. Gonna be close and a nail biter! But these set up's usually are. Like I said, if the snowfall rate is heavy enough, we can overcome the marginal thermal profile and surface temps. This might be an interesting system here. It's going to probably cause me to stay up for the 0Z NAM now.

Same here Les and then heading to bed

Ditto!

A bit early to tell what the final outcome will be on the 0Z NAM but out to Hour 24, it's already warmer with the thermals vs 18Z valid for the same time. So that tells me it should be coming in stronger as well. We'll know for sure here shortly.

Yep... definitely coming in stronger with the rain / snow line very close to us in the Metro. Start time is a little slower then the 0Z HRRR, probably an hour or two later Sun morning. Heavier rates though are definitely helping to keep us snow down here. That is really going to be so critical with this system. QPF at CVG is coming in at 0.23"

Ok guys, headed to bed. If anyone is up for the RGEM, GFS, Euro etc, please post! Otherwise, I'll be back in the morning with coffee and we'll see how things look then for not only Sunday but for next week as well. Buckle up!

Interesting run and see a low to the east but is that the southern energy or does the northern energy end up stronger and forms the low to the east.

tpweather wrote: ↑Fri Jan 20, 2023 9:25 pm Interesting run and see a low to the east but is that the southern energy or does the northern energy end up stronger and forms the low to the east.

On both the HRRR and NAM runs, I think we are seeing the northern energy staying a bit more intact to your point Tim, and we are seeing a little bit better of a phase. Better moisture influx from the Gulf as a result so we are seeing heavier precip rates to keep us more in the way of snow.

we should have started a thread for the Sunday storm

airwolf76 wrote: ↑Fri Jan 20, 2023 9:36 pm we should have started a thread for the Sunday storm

You could have started it, Charles. I'll start it since no one else has. I was hoping someone else would since my luck hasn't been so great.

Please use the new thread to discuss tomorrow's system. Thanks all!

https://absolutevorticity.com/viewtopic.php?t=216