12/10-11 Disco / Obs - Rain/Snow/Wind Event

[AtlanticWx]

new hrdps, less amplified and more of a positive tilt leads to a less snowier solution. gonna have to see what 0z does before seeing if this is a trend  

[NorthArlington101]

new hrdps, less amplified and more of a positive tilt leads to a less snowier solution. gonna have to see what 0z does before seeing if this is a trend  

I love having as many models as possible show the snowiest outcome, so it’s annoying to see any model get worse.

That said, the HDRPs has had some of the most stubborn and worst fails in my recollection. Anyone remember when it gave Baltimore like 36” of snow 2 days out, maybe that was in 2021?

[AtlanticWx]

Just now, NorthArlington101 said:

I love having as many models as possible show the snowiest outcome, so it’s annoying to see any model get worse.

That said, the HDRPs has had some of the most stubborn and worst fails in my recollection. Anyone remember when it gave Baltimore like 36” of snow 2 days out, maybe that was in 2021?

i remember it showing like 10" for march 2022 for the longest time

[NorthArlington101]

Hrrr 18z looks significantly more amplified v 12z. Nice trend. NAM looks a mess at 18z which isn’t uncommon it’s bouncy AF. 
 
Which brings me to…what is NCEPs high res short range flag ship model of choice now anyways???  They stopped updating the NAM and SREF years ago. Which was fine they’re ancient and probably outlived the usefulness of tweaking their core at this point. But they were never replaced.  The HRRR isn’t any more reliable and seems mostly ignored. The ARW FV3 I don’t think ever became operational (unless I missed that) and is largely absent in any forecast discussion. The RRFS has been in development for years and still isn’t operational. Frankly in most discussions of short range Synoptics they still talk about the euro and gfs mostly. So…what exactly is the current preferred high res short range guidance? Any of the pros in this area want to chime in? 

Let’s hope they just prefer the GFS because it looks nice at 18z

[jayyy]

i remember it showing like 10" for march 2022 for the longest time

There was a storm last year where it was being very stubborn about giving us a solid hit until the night before.. even though all other guidance had shifted away from that possibility.


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[jayyy]

Let’s hope they just prefer the GFS because it looks nice at 18z

And let’s face it… it IS the best model these days post upgrade.


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[AtlanticWx]

gfs better fs

[psuhoffman]

2 minutes ago, NorthArlington101 said:

Let’s hope they just prefer the GFS because it looks nice at 18z

I’m legit curious what  NWS and NCEP prefer when making short range forecasts. But honestly given the inconsistency of all high res (especially the NAMs) I tend to still weight the GFS/Euro for giving me the general Synoptics then use common sense and the high res to get an idea what the meso scale features will look like.  But I apply those meso features to the GFS/Euros larger synoptic representation. I don’t trust the high res models at all for picking up trends wrt the larger features. 

[Terpeast]

2 minutes ago, psuhoffman said:

I’m legit curious what  NWS and NCEP prefer when making short range forecasts. But honestly given the inconsistency of all high res (especially the NAMs) I tend to still weight the GFS/Euro for giving me the general Synoptics then use common sense and the high res to get an idea what the meso scale features will look like.  But I apply those meso features to the GFS/Euros larger synoptic representation. I don’t trust the high res models at all for picking up trends wrt the larger features. 

Thats probably what the NWS offices do as well. 

[jayyy]

gfs better fs

This actually makes more sense vs. what the mesos are showing. Yes, CAPEs area is further east, but they’ll also see more significant precip from the coastal low. That secondary pocket of 2-3” east of the bay would make sense in this scenario. Later flip, but more intense precip.


Edit — ratios won’t be 10:1 but rates will play a huge factor.

[Stormchaserchuck1]

18z gfs: Widespread 0.1-0.5"

[cbmclean]

9 minutes ago, jayyy said:

And let’s face it… it IS the best model these days post upgrade.


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I haven't seen any of the 500 HP verification scores lately.  There was a time not too long ago when the GFS had dropped to third behind the CMC.  Is that no longer true?

[jayyy]

I haven't seen any of the 500 HP verification scores lately.  There was a time not too long ago when the GFS had dropped to third behind the CMC.  Is that no longer true?

I haven’t checked verification scores either tbh, but it certainly feels like the GFS has been pretty money over the past year or so.

[stormy]

1 minute ago, jayyy said:

I haven’t checked verification scores either tbh, but it certainly feels like the GFS has been pretty money over the past year or so.

I have been saying for a long time. Don't ignore the GFS.............

[WEATHER53]

1 hour ago, Huffwx said:

This. That 500 low goes negative a low forms over South Carolina

Hey you!

[high risk]

21 minutes ago, jayyy said:

I haven’t checked verification scores either tbh, but it certainly feels like the GFS has been pretty money over the past year or so.

       If we're talking about Northern Hemisphere Day 5  anomaly coefficient at 500 mb, which is generally considered the standard metric for synoptic performance, the GFS has been solidly in 4th place for most of this year, trailing the ECMWF, UKMET, and CMC.

[AtlanticWx]

if anyone cares, RAP is better

[CAPE]

49 minutes ago, jayyy said:

This actually makes more sense vs. what the mesos are showing. Yes, CAPEs area is further east, but they’ll also see more significant precip from the coastal low. That secondary pocket of 2-3” east of the bay would make sense in this scenario. Later flip, but more intense precip.


Edit — ratios won’t be 10:1 but rates will play a huge factor.

I would love this to reflect ground truth, but it won't be (as most of us know). At this point I think there is a decent shot of non accumulating snow in the air east of the Fall line, and an inch or 2 up your way, with several inches in the western highlands. That would be an area wide win imo given how this looked not too long ago.

[high risk]

1 hour ago, psuhoffman said:

Hrrr 18z looks significantly more amplified v 12z. Nice trend. NAM looks a mess at 18z which isn’t uncommon it’s bouncy AF. 
 

Which brings me to…what is NCEPs high res short range flag ship model of choice now anyways???  They stopped updating the NAM and SREF years ago. Which was fine they’re ancient and probably outlived the usefulness of tweaking their core at this point. But they were never replaced.  The HRRR isn’t any more reliable and seems mostly ignored. The ARW FV3 I don’t think ever became operational (unless I missed that) and is largely absent in any forecast discussion. The RRFS has been in development for years and still isn’t operational. Frankly in most discussions of short range Synoptics they still talk about the euro and gfs mostly. So…what exactly is the current preferred high res short range guidance? Any of the pros in this area want to chime in? 

   

     I'll chime in, the answers (opinions??)  are complicated and nuanced.     The HRRR is still the flagship CAM, but it has primarily been tuned for deep convection, and I hesitate to use it much for winter weather, especially with cold air damming events.   The HRRR also hasn't been updated in way too long, because all efforts are on RRFS, which hasn't come together as quickly as planned.    The NAM Nest, IMHO, is still very good for precip type, although it runs a bit on the cold side and is wet, but there isn't currently a CAM that does better with cold air damming.   There are 3 HiRes Windows (ARW, ARW2, and FV3) - they are all operational, but I don't love them for winter weather.    The FV3 HiRes Window is particularly bad for thermal profiles.

    If I had to pick a CAM for winter, I'd go with the NAM Nest, but I'd be weary of its synoptic errors beyond 36-48 hours and realize that it runs a bit on the cold side.

 

[stormy]

25 minutes ago, high risk said:

       If we're talking about Northern Hemisphere Day 5  anomaly coefficient at 500 mb, which is generally considered the standard metric for synoptic performance, the GFS has been solidly in 4th place for most of this year, trailing the ECMWF, UKMET, and CMC.

It would definitely trail the CMC for rationational cooling nightly lows.

[stormy]

Searching for a better short range model than the NAM as suggested by psu.

Lets try the NDFD

I could buy this.

[high risk]

2 minutes ago, stormy said:

Searching for a better short range model than the NAM as suggested by psu.

Lets try the NDFD

I could buy this.

 

         NDFD is the gridded NWS forecast    

[Kmlwx]

2 minutes ago, high risk said:

         NDFD is the gridded NWS forecast    

Was just about to post this  

[stormy]

8 minutes ago, high risk said:

         NDFD is the gridded NWS forecast    

Thanks

[psuhoffman]

can we get one winter where the 90% on the gefs hits every storm?  

[NorthArlington101]

can we get one winter where the 90% on the gefs hits every storm?  

Our current “most likely” 10:1 outcome was the 90% on the GEFS ~24 hours ago… it’s still just correcting to the truth

[psuhoffman]

3 minutes ago, NorthArlington101 said:

Our current “most likely” 10:1 outcome was the 90% on the GEFS ~24 hours ago… it’s still just correcting to the truth

That’s kinda what inspired me to make that comment. 

[AtlanticWx]

2 minutes ago, psuhoffman said:

That’s kinda what inspired me to make that comment. 

if we can get one more day of trends like these, maybe we can have model outputs showing 6". just a thought tho, doubt it happens

[Huffwx]

1 hour ago, WEATHER53 said:

Hey you!

Hey now, Howard. It's been a minute.

[AtlanticWx]

euro coming in with more of a - tilt, less snow for areas west tho and i'm not sure why