Absolute Vorticity

18Z NAM fizzles out a lot of the precip coming in from Indiana. The NAM so far, has never really been gung ho on this system anyway. Latest from the boys... pretty short and sweet today.

An active long range forecast is in store for the region. Friday
starts with increasing and thickening high cloud cover. An upper
ridge crosses to the northeast and some light precipitation may
punch through a very dry lower atmosphere overnight for some
flurries or light snow. The occurrence of this will increase towards
daybreak, with the maxima passing south of the region from KY into
WV. Any snow will change to rain during the day. Lingering precip
overnight and into Sunday will likely be a rain with some snow mixed
in and change to all rain where it is occurring on Sunday. KY and
southern OH will see the best chances for snow and precip Saturday.
Otherwise, precip through the weekend is expected to be generally
light. An upper level trough passes to the east and any precip
should end from west to east Sunday morning.

Good Afternoon and yes we have tons to talk about. Les you mentioned the second piece of energy on Sunday and I believe we need to watch this as well. I believe models are just having problem figuring out where the energy is going to be located and when the highest energy level is around. I will look at this more this evening and of course on Thursday.

We'll get into the Hi Res models tomorrow so hopefully, we can start to pin this thing down a little more closely... although I think we've got a pretty good idea right now as it is.

tron777 wrote: ↑Wed Jan 03, 2024 1:56 pm You should probably move that post to the La Bomba thread.

Are you saying Trevor needs to be moderated...

fyrfyter wrote: ↑Wed Jan 03, 2024 4:43 pm

tron777 wrote: ↑Wed Jan 03, 2024 1:56 pm You should probably move that post to the La Bomba thread.

Are you saying Trevor needs to be moderated...

Someone's got to keep an eye on him!

0.33" QPF at CVG on Sat from the 18Z GFS. An additional 0.10" for Sunday. Again, marginal thermals so if the precip rate is heavy, we'll see snow. Once it lightens up, rain / drizzle. What I believe should happen is all snow late Fri night into the day on Sat. Probably changing to light rain / drizzle Sat afternoon once the initial wave passes. A mix of light rain / snow showers for Sunday with the passage of the upper trough.

Good Evening and do we have this storm down for the weekend and for the most part yes but like all systems there can be a surprise or two. Really two systems with the first starting late Friday into Saturday afternoon. Les I agree this starts out as snow and I can many folks locally getting a quick inch by 10am or so. Then it gets messy and do we have the warmer layer take over and precip rates go down and we get the lovely drz/light rain and a few flakes mixed in the rest of the day or do we stay snow into the afternoon. I believe the changeover is more likely since we don't have a ton of cold around.

Sunday is somewhat different as we have a trough moving in with colder air and I believe most of the showers on Sunday will be in the form of snow where some folks could get up to another inch.

So my forecast is 1-2 inches total for the weekend with a changeover Saturday during the day and then we get the snow showers on Sunday. Temps will be marginal even if its all snow especially as we get into the day on Saturday with temps more than likely getting to the mid 30's. Sunday will be the opposite as colder air continues to move in and really Sunday evening may be the worse part in terms of travel with the snow showers and temps falling.

I think that is a very fair call Tim. What folks also need to keep in mind is that you won't see that 1-2" on the ground all at once. You'll get a covering, it'll melt, then perhaps another covering on Sunday. It'll be one of those deals.

I agree Les and to me its always been about precip types. Always thought there would be snow involved but like you mentioned even if we get 2 inches you won't see that on the ground at one time. Good thing is another storm which really has my interest is just a few days later and will talk more about that in the other thread.

The storm itself is still off the West Coast so we should get a touch of sampling with the 0Z runs tonight and a much better sampling with the 12Z run tomorrow. If we are going to see any changes (good or bad) it should be with the next 2 cycles.

18Z RGEM drops 1-3" across the area. 1" north to 3" in the far South and SE.

things are still looking okay for my area. I am thinking a general 6-12" if i can manage to stay all snow

Will monitor future runs, but there has been a trend for a "sweet spot" of snow either right over Cincinnati or just to the south of the river. Something to watch. But it's been showing up on a few runs now. Wherever that area is will have the best risk for 3" (maybe isolated 4").

Hopefully the higher res models will be able to help with narrowing down where that will be.

Trevor wrote: ↑Thu Jan 04, 2024 2:56 am Will monitor future runs, but there has been a trend for a "sweet spot" of snow either right over Cincinnati or just to the south of the river. Something to watch. But it's been showing up on a few runs now. Wherever that area is will have the best risk for 3" (maybe isolated 4").

Good Morning Trev, I have noticed that and that is why your first forecast always had merit. I believe the hardest forecast when doing a snowfall map is when other types of precip is involved. Always hard to put down a narrow accumulation and sometimes the wider range is needed. Looks like plenty of forecasting with this system since we are still about 48 hrs away from the start.

6Z NAM finally joins the party to give us QPF. 0.14" at CVG for Sat. 0Z GFS has 0.29" and the 0Z Euro had 0.16" I don't really have any changes to my call.

Looking good for you Trev, I’ll be happy too , especially if my backyard gets the 3

We should be able to really hone in on this thing today as it starts to get more into the hi-res guidance's wheel house. The energy is pushing onshore now with rain / mountain snow in the Pacific NW.

tron777 wrote: ↑Thu Jan 04, 2024 6:40 am We should be able to really hone in on this thing today as it starts to get more into the hi-res guidance's wheel house. The energy is pushing onshore now with rain / mountain snow in the Pacific NW.

With the jet being active sometimes its hard for the models to get a true handle on where the energy may be located. Sometimes the model pushes it east faster and you lose some of the strength of a system but also you tend to get several pieces of energy in the jet stream and sometimes a weaker piece all of a sudden gets enhanced when another piece of energy catches up. I believe that is why models may still go back and forth over the next day or so trying to pick out those pieces of energy and where they may be located.

tpweather wrote: ↑Thu Jan 04, 2024 6:49 am

tron777 wrote: ↑Thu Jan 04, 2024 6:40 am We should be able to really hone in on this thing today as it starts to get more into the hi-res guidance's wheel house. The energy is pushing onshore now with rain / mountain snow in the Pacific NW.

With the jet being active sometimes its hard for the models to get a true handle on where the energy may be located. Sometimes the model pushes it east faster and you lose some of the strength of a system but also you tend to get several pieces of energy in the jet stream and sometimes a weaker piece all of a sudden gets enhanced when another piece of energy catches up. I believe that is why models may still go back and forth over the next day or so trying to pick out those pieces of energy and where they may be located.

I am doing a little nowcasting here Tim... but if you look at the SPC Mesopage, you will notice a 1004 MB low over Western New Mexico. Guidance has been showing it at 1007 MB which is wrong. I could be grasping at straws here, but I wonder if this system is actually a little bit stronger then what the models are indicating?

tron777 wrote: ↑Thu Jan 04, 2024 6:54 am

tpweather wrote: ↑Thu Jan 04, 2024 6:49 am

tron777 wrote: ↑Thu Jan 04, 2024 6:40 am We should be able to really hone in on this thing today as it starts to get more into the hi-res guidance's wheel house. The energy is pushing onshore now with rain / mountain snow in the Pacific NW.

With the jet being active sometimes its hard for the models to get a true handle on where the energy may be located. Sometimes the model pushes it east faster and you lose some of the strength of a system but also you tend to get several pieces of energy in the jet stream and sometimes a weaker piece all of a sudden gets enhanced when another piece of energy catches up. I believe that is why models may still go back and forth over the next day or so trying to pick out those pieces of energy and where they may be located.

I am doing a little nowcasting here Tim... but if you look at the SPC Mesopage, you will notice a 1004 MB low over Western New Mexico. Guidance has been showing it at 1007 MB which is wrong. I could be grasping at straws here, but I wonder if this system is actually a little bit stronger then what the models are indicating?

Good Morning Les and I believe your are correct about the system being somewhat stronger. This should be fun to watch today and see if the models catch up to the strength of this system.

tpweather wrote: ↑Thu Jan 04, 2024 7:00 am

tron777 wrote: ↑Thu Jan 04, 2024 6:54 am

tpweather wrote: ↑Thu Jan 04, 2024 6:49 am

tron777 wrote: ↑Thu Jan 04, 2024 6:40 am We should be able to really hone in on this thing today as it starts to get more into the hi-res guidance's wheel house. The energy is pushing onshore now with rain / mountain snow in the Pacific NW.

With the jet being active sometimes its hard for the models to get a true handle on where the energy may be located. Sometimes the model pushes it east faster and you lose some of the strength of a system but also you tend to get several pieces of energy in the jet stream and sometimes a weaker piece all of a sudden gets enhanced when another piece of energy catches up. I believe that is why models may still go back and forth over the next day or so trying to pick out those pieces of energy and where they may be located.

I am doing a little nowcasting here Tim... but if you look at the SPC Mesopage, you will notice a 1004 MB low over Western New Mexico. Guidance has been showing it at 1007 MB which is wrong. I could be grasping at straws here, but I wonder if this system is actually a little bit stronger then what the models are indicating?

Good Morning Les and I believe your are correct about the system being somewhat stronger. This should be fun to watch today and see if the models catch up to the strength of this system.

Thank you Tim! Glad you are seeing what I am seeing. I've also been checking some of the hi-res guidance this morning like the Hi-res NAM for example, and I am noticing that on some of the models, they are bringing back the surface low, or the primary low into extreme NE TN then it does the transfer to the EC Low. The original solution from several days ago was for a stronger primary low into WV then it transfers. Now I doubt we get that solution back, but even a weaker version into NE TN would still be a good thing in getting more moisture for us involved with this system.

tron777 wrote: ↑Thu Jan 04, 2024 7:06 am

tpweather wrote: ↑Thu Jan 04, 2024 7:00 am

tron777 wrote: ↑Thu Jan 04, 2024 6:54 am

tpweather wrote: ↑Thu Jan 04, 2024 6:49 am

tron777 wrote: ↑Thu Jan 04, 2024 6:40 am We should be able to really hone in on this thing today as it starts to get more into the hi-res guidance's wheel house. The energy is pushing onshore now with rain / mountain snow in the Pacific NW.

With the jet being active sometimes its hard for the models to get a true handle on where the energy may be located. Sometimes the model pushes it east faster and you lose some of the strength of a system but also you tend to get several pieces of energy in the jet stream and sometimes a weaker piece all of a sudden gets enhanced when another piece of energy catches up. I believe that is why models may still go back and forth over the next day or so trying to pick out those pieces of energy and where they may be located.

I am doing a little nowcasting here Tim... but if you look at the SPC Mesopage, you will notice a 1004 MB low over Western New Mexico. Guidance has been showing it at 1007 MB which is wrong. I could be grasping at straws here, but I wonder if this system is actually a little bit stronger then what the models are indicating?

Good Morning Les and I believe your are correct about the system being somewhat stronger. This should be fun to watch today and see if the models catch up to the strength of this system.

Thank you Tim! Glad you are seeing what I am seeing. I've also been checking some of the hi-res guidance this morning like the Hi-res NAM for example, and I am noticing that on some of the models, they are bringing back the surface low, or the primary low into extreme NE TN then it does the transfer to the EC Low. The original solution from several days ago was for a stronger primary low into WV then it transfers. Now I doubt we get that solution back, but even a weaker version into NE TN would still be a good thing in getting more moisture for us involved with this system.

I was noticing the same thing when looking at the short range Canadian. Gotta watch that.

Trevor wrote: ↑Thu Jan 04, 2024 7:18 am

tron777 wrote: ↑Thu Jan 04, 2024 7:06 am

tpweather wrote: ↑Thu Jan 04, 2024 7:00 am

tron777 wrote: ↑Thu Jan 04, 2024 6:54 am

tpweather wrote: ↑Thu Jan 04, 2024 6:49 am

With the jet being active sometimes its hard for the models to get a true handle on where the energy may be located. Sometimes the model pushes it east faster and you lose some of the strength of a system but also you tend to get several pieces of energy in the jet stream and sometimes a weaker piece all of a sudden gets enhanced when another piece of energy catches up. I believe that is why models may still go back and forth over the next day or so trying to pick out those pieces of energy and where they may be located.

I am doing a little nowcasting here Tim... but if you look at the SPC Mesopage, you will notice a 1004 MB low over Western New Mexico. Guidance has been showing it at 1007 MB which is wrong. I could be grasping at straws here, but I wonder if this system is actually a little bit stronger then what the models are indicating?

Good Morning Les and I believe your are correct about the system being somewhat stronger. This should be fun to watch today and see if the models catch up to the strength of this system.

Thank you Tim! Glad you are seeing what I am seeing. I've also been checking some of the hi-res guidance this morning like the Hi-res NAM for example, and I am noticing that on some of the models, they are bringing back the surface low, or the primary low into extreme NE TN then it does the transfer to the EC Low. The original solution from several days ago was for a stronger primary low into WV then it transfers. Now I doubt we get that solution back, but even a weaker version into NE TN would still be a good thing in getting more moisture for us involved with this system.

I was noticing the same thing when looking at the short range Canadian. Gotta watch that.

I've noticed it Trev on like 3 different short range models. Would love to see that trend continue with the 12Z suite today.

I will be making some minor adjustments to the map most likely. Especially to trim down the southern edge due to track/quicker mixing. Basically shifting everything north a bit.