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Pattern Fabulous February

Nc probably will see winter weather sometime next week. Outside of there I just don’t see it. Especially without support


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Jessy89 said:
Nc probably will see winter weather sometime next week. Outside of there I just don’t see it. Especially without support


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Even here in nc I don’t like this setup, as @Webberweather53 just stated you want the artic airmass here first not when the precip has already started, things like increasing dew points and heat released from raindrops would argue for it to be warmer at the sfc
 
FV3 is not blinking, though, and we are 6 days out now. It was really good in this range with the December storm, which was also a CAD storm, while the other models had to play catch up, even inside 5 days. Guess we will see if it is right again.
 
Storm5 said:
There isn’t much support for even NC.....


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I agree. One model against many. I could say the NAM was great in Dec 2017 but was it right 70% of the time as the lead model? No. The FV3 is consistent but likely consistently wrong as it has been most of the year. It just got lucky in December.
 
Here's a GIF showing the dewpoint crashing as the 1040+ HP build in. The key to watch IMO is going to be the LP track and how strong that HP is. If it is 1040+ and builds in like the FV3 shows than an ice storm is entirely possible.

fv3p_Td2m_eus_fh138-162.gif

The FV3 has a 1045 HP that builds in.
1549459553259.png

The old GFS has a 1043 HP building in but it's a bit further north with the LP in the midwest and with the HP.
1549459584569.png

Meanwhile the Euro has a 1034 HP that is sliding off the coast.
1549459666420.png
 
Looking at initialized conditions vs what other models predicted for the HP across southern Canada can sometimes be a useful way to figure out model bias. When I look at what we see observed vs what models showed roughly 6 days out it's pretty clear which model did best with the overall LP track and HP strength (although slightly overdone). This doesn't mean it will perform the same for this system we are tracking but it does show that the FV3 6 days out pretty much nailed the exact positions of the two HP's and the LP out in Colorado and was just a little too strong with the HP's. Obviously each setup is different but my point is that when looking at 6 day forecasts vs reality the FV3 nailed our current setup 6 days out which is pretty impressive to me.

12km NAM 6z initialization. We have a 1036 HP up in southern Canada and a 1040 HP in western Canada.

1549459988965.png

Now let's look at what the FV3 showed 6 days ago for our current observed state. Both HP's were 2-3mb too strong on the FV3 but the LP track and HP positions are almost identical to what the NAM observed. That's impressive.

1549460093403.png

The GFS was too far south and strong with the western HP and too weak with the eastern one by 2mb. The primary LP is way too far east in Illinois vs Colorado as observations show.
1549460160152.png

Here's the CMC, since it runs off hours I went with it's hour 138 forecast. You can see it's pretty far off with the HP strength and position, it's not even close except the LP track.
1549460235667.png

Now here is the Euro. It did not do a good job with the HP position and the strength of the western HP was 5mb weaker than current observations. The LP position is spot on.
1549460308993.png
 
I think we have a punt! From WxSouthFCAEBA40-4872-4A72-8898-27628E409B78.png
 
Storm5 said:
There isn’t much support for even NC.....


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Exactly and I'm not agreeing to be negative, but factual. The FV3 is on an island right now with absolutely no support from any other modeling, although I guess one could argue that the GFS leaned that way. I still think if we get those strong HP's to keep dropping down out of Canada we can score at some point, will it be this system? I'd like to see something else lean that way before I get even the least bit excited and if the fv3 loses, then we all need to acknowledge it's 5+ day failure
 
metwannabe said:
Exactly and I'm not agreeing to be negative, but factual. The FV3 is on an island right now with absolutely no support from any other modeling, although I guess one could argue that the GFS leaned that way. I still think if we get those strong HP's to keep dropping down out of Canada we can score at some point, will it be this system? I'd like to see something else lean that way before I get even the least bit excited and if the fv3 loses, then we all need to acknowledge it's 5+ day failure
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This is the only storm that the FV3 has latched onto and shown wintry solutions for NC since the early December storm. Sure it's thrown around some interesting day 7+ ideas that haven't verified but it has locked onto the idea of a wintry/icy event for NC and it's shown this general idea for days now. We are getting inside the day 6 range where it's very good with synoptics and I demonstrated above how at day 6 it matched up almost spot on with current observations and the Euro was pretty far off by contrast. It could certainly be too cold biased so that's something to watch going forward; it will also depend on what the 5H energy does and if it cuts/how strong.
 
snowlover91 said:
This is the only storm that the FV3 has latched onto and shown wintry solutions for NC since the early December storm. Sure it's thrown around some interesting day 7+ ideas that haven't verified but it has locked onto the idea of a wintry/icy event for NC and it's shown this general idea for days now. We are getting inside the day 6 range where it's very good with synoptics and I demonstrated above how at day 6 it matched up almost spot on with current observations and the Euro was pretty far off by contrast. It could certainly be too cold biased so that's something to watch going forward; it will also depend on what the 5H energy does and if it cuts/how strong.
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But all the other models have done this, too.
 
snowlover91 said:
This is the only storm that the FV3 has latched onto and shown wintry solutions for NC since the early December storm. Sure it's thrown around some interesting day 7+ ideas that haven't verified but it has locked onto the idea of a wintry/icy event for NC and it's shown this general idea for days now. We are getting inside the day 6 range where it's very good with synoptics and I demonstrated above how at day 6 it matched up almost spot on with current observations and the Euro was pretty far off by contrast. It could certainly be too cold biased so that's something to watch going forward; it will also depend on what the 5H energy does and if it cuts/how strong.
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It actually "locked" on to a winter storm for this weekend but lost it and then it became this one.... I don't have time to read back through everything and I'm not seeking an argument but there were post made then about how it was locked in and led the way, well that's now gone and here we are talking about something a couple days later. I hope it verifies, I want winter weather I'd love to get some snow and even some ice but I'd just feel more confident if it had more support.
 
Brick Tamland said:
But all the other models have done this, too.
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Correct, people like to harp on a model because it shows something 7+ days out that is gone the next run and they label the model as inaccurate because of that. I've been following the FV3 very closely since winter started and it has been very good, possibly the best, model inside 6 days IMO. This will be another big test for it so we will need to see what it does the next few runs. The GFS is pretty close to it, just doesn't push the cold air down as much.
 
I think this needed to be posted here about what the FV3 has shown in the past.

snowlover91 said:
It had one run 174 hours out (7+ days away) showing wintry weather for NC this weekend and every other run after that was dry/no winter weather. Not once inside 6 days has it shown anything wintry for this weekend. I think this upcoming 11-12th storm is different. It hasn't shown it a few random runs, it has consistently been depicting it for DAYS now and we are now getting inside 6 days where the FV3 does very well from the limited sample size we have.

View attachment 15098

Next run took that away and it hasn't shown anything at all inside 6 days.
View attachment 15099

And here is it's current 84 hour forecast for this time period.
View attachment 15100
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snowlover91 said:
Here's a GIF showing the dewpoint crashing as the 1040+ HP build in. The key to watch IMO is going to be the LP track and how strong that HP is. If it is 1040+ and builds in like the FV3 shows than an ice storm is entirely possible.

View attachment 15088

The FV3 has a 1045 HP that builds in.
View attachment 15089

The old GFS has a 1043 HP building in but it's a bit further north with the LP in the midwest and with the HP.
View attachment 15090

Meanwhile the Euro has a 1034 HP that is sliding off the coast.
View attachment 15091
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My bets would be on the Euro in terms of the high. We know the GFS always seems to overpower its high strengths. Maybe let's come back to this post in 5 days and see which was closer.
 
ForsythSnow said:
My bets would be on the Euro in terms of the high. We know the GFS always seems to overpower its high strengths. Maybe let's come back to this post in 5 days and see which was closer.
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Yeah but look at post #1448 in this thread. I demonstrated the observed HP positions and strengths vs what models roughly 6 days out projected. The FV3 was the best hands down although it was a touch too strong with them. The Euro was actually pretty bad overall. Every storm and scenario is different though, this will be a great test for the FV3 and I'm watching it closely to see how it does.

The biggest unanswered question for me is if it has a cold bias inside 6 days with this type of setup or if it's handling the CAD better at this range than other models (and something they will gradually show with time). Since we only have had 1 legitimate winter storm here in NC it's tough to know but this storm will give us a good idea if the FV3 is the new model of choice inside 6 days or not.
 
I'd probably put the Euro Op in there instead of or alongside the EPS. An op vs an ensemble suite isn't really apples to apples, although it is still an interesting comparison. My guess is that the FV3 is overdone on the strength of the high, the duration of it locking in, and thus the strength and degree of the wedge. But we'll see!
 
Rain Cold said:
I'd probably put the Euro Op in there instead of or alongside the EPS. An op vs an ensemble suite isn't really apples to apples, although it is still an interesting comparison. My guess is that the FV3 is overdone on the strength of the high, the duration of it locking in, and thus the strength and degree of the wedge. But we'll see!
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Fair enough! Here is the 6z FV3 vs the Euro 3 run trend.

1549466324661.png

Euro 3 run trend
ecmwf_mslpa_us_fh144_trend.gif
 
Getting the feeling this will be similar to the ice event that effected NC a few weeks ago, some areas in the foothills got 0.5 of ice accretion, fv3 was actually a little to warm in that situation
 
I find it hard to believe, that the Fv3 will produce of WS with absolute no support for NC.
 
Myfrotho704_ said:
Getting the feeling this will be similar to the ice event that effected NC a few weeks ago, some areas in the foothills got 0.5 of ice accretion, fv3 was actually a little to warm in that situation
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Wasn’t it totally too cold over central NC though? It has snow/mix/ice over wake county and was almost certain over border counties such as Granville, and it was all cold rain.


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Six Mile Wx said:
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So, in a nutshell, the first cluster (cold) is a -EPO with a +PNA while the 2nd one (warm) is a -EPO with a -PNA. What’s interesting is that the cold cluster has a +NAO whereas the warm one has a -NAO. Is that weird? Is it possible that a very strong -EPO with +PNA typically is cold only with a +NAO or is this just an unusual setup? I know that there is a pretty good correlation of -NAO to SE cold in general. But perhaps too much blocking from both the -EPO and -NAO sectors typically results in SE warmth instead of SE cold??? I’m just thinking out loud here and trying to generate discussion. One thing’s for certain: a +PNA is quite crucial.
 
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Jon said:
Wasn’t it totally too cold over central NC though? It has snow/mix/ice over wake county and was almost certain over border counties such as Granville, and it was all cold rain.


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When it was 72+ hours out it actually had the storm track a bit far north, it also barely showed any ice for CAD areas and was warmer, but nearing the onset the fv3 shifted way colder, it actually showed some front end snow showers lol as time got closer C7861389-7696-4FD9-AF95-1E3DDDCEB506.png
 
GaWx said:
So, in a nutshell, the first cluster (cold) is a -EPO with a +PNA while the 2nd one (warm) is a -EPO with a -PNA. What’s interesting is that the cold cluster has a +NAO whereas the warm one has a -NAO. Is that weird? Is it possible that a very strong -EPO with +PNA typically is cold only with a +NAO or is this just an unusual setup? I know that there is a pretty good correlation of -NAO to SE cold in general. But perhaps too much blocking from both the -EPO and -NAO sectors typically results in SE warmth instead of SE cold??? I’m just thinking out loud here and trying to generate discussion. One thing’s for certain: a +PNA is quite crucial.
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It looks like it’s not a true -NAO to me and come verification it may not even be a -NAO. I truly do think it lies with the PNA as you said. I think the fake -NAO is in response to the -EPO/-PNA couplet, popping a SE ridge, leading to a trough over the northern Atlantic which in turn pops a -NAO downstream.

I’ve been watching that ridging to see if it’s possible to connect to the -EPO for a -EPO/+PNA look. I don’t have cluster data so it’s very interesting that the modeling as many members with this look.


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Does anyone have an official date the GFS is replaced by the FV3? I'm looking forward to being able to view the "FV3" ensembles.
 
Shawn said:
Does anyone have an official date the GFS is replaced by the FV3? I'm looking forward to being able to view the "FV3" ensembles.
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Last I heard was March something. Also, the ensembles are not going to change at the same time, so we will be stuck with the old GEFS for a while longer.
 
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