February 18-19 Event

[hazwoper]

0Z NAM clown map paints 12+ Of frozen for SEPA.

Discuss

[LVblizzard]

Damn...you beat me with this thread by seconds.

I’m really liking this event for a good front-end thump...maybe a general 4-8” or 5-10” for the area. It seems like the kind of storm where the front-end snow overperforms while the rest of the storm is just occasional frozen IP/ZR junk. Fortunately the models aren’t big on significant icing for this one.

[jhotdog]

Any Nam Maps?

[Albedoman]

I had thought this exact same scenario playing out and stated in my blog a four  hours ago after the 18Z NAM run. Tonight's 0Z NAM runs looks like it is confirming my thoughts. Typical overrunning situation. Winter storm watches should be hiked by tomorrow evening for our area  if the NAM model stays consistent in tomorrows day runs  LMAO if the runs remain  consistent though. Its a keeper in my book after the crap we have tonight.

 

[Moderately Unstable]

I was so close to saying something in the 18z time frame...the rpm and graf both supported an insane overrunning banding setup. Clown totals for the corridor and nw, hellish gradient though. They were supportive of 12+ as well on the corridor...down to nothing SE of around Lindenwold. I considered that a good sign bc in earlier storms the rpm picked up on warmth earlier than the globals. That it hasn't here is good. I want to see the full 00z suite before I make further comments. You could tell at 18 from the 3k that the 12km was too amped. Fwiw iirc the 21z rpm had a stripe of 20" totals in the harr ne towards the LV area. I am super hesistant to invest this season given the model insanity but I like this setup. I'm much more bullish about this than I was about the weekend or today. Objectively, not as a weenie--we have good odds here. Buckle up folks.

[Ralph Wiggum]

NAVGEM was a complete mauling. 

[Ralph Wiggum]

GFS has the f gen banding across SE PA. Nice hit.

[Ralph Wiggum]

This is quickly trending mostly if not all frozen

[hazwoper]

Low further east this run.  Nice run

[hazwoper]

Just now, Ralph Wiggum said:

This is quickly trending mostly if not all frozen

Yep all frozen even to 95 this run

[Ralph Wiggum]

4 minutes ago, hazwoper said:

Yep all frozen even to 95 this run

Ends as snow to boot. 

[Ralph Wiggum]

I guess so much for upper 50s to low 60s on Thursday that was progged a couple days ago. 

[RedSky]

It's morphing into a different beast, looks like the December storm on the GFS.

 

[Ralph Wiggum]

Para is a 2 parter.....waa thump then the coastal. Still snowing 7am Friday AM. Wow.

[Moderately Unstable]

I love a good finale, don't you? 00z RPM keeps the trend of the 18z and 21z runs....corridor mostly snow, gives 12-16 widespread totals. Places like BAL & IAD are modeled at between 20-24" (outside of our domain but notable). Gotta keep watching this though. There's a sweet spot here for the track of the sfc and 850 low centers. The models have hit that place now. My internal sense here is, the whole 12+" thing...we've been down this road many times. Models a couple days out provide clown like totals. I think we're reaching consensus now that impacts are going to be enough here--in the form of snow--to most likely at some point down the road req a WSW for the corridor and areas NW. Exactly what the totals are...probably too soon to say, but I sure do love the 00z runs coming in now. If I were a TV met this is when I'd start talking more substantively about the "potential". 

[Heisy]

10 minutes ago, Moderately Unstable said:

I love a good finale, don't you? 00z RPM keeps the trend of the 18z and 21z runs....corridor mostly snow, gives 12-16 widespread totals. Places like BAL & IAD are modeled at between 20-24" (outside of our domain but notable). Gotta keep watching this though. There's a sweet spot here for the track of the sfc and 850 low centers. The models have hit that place now. My internal sense here is, the whole 12+" thing...we've been down this road many times. Models a couple days out provide clown like totals. I think we're reaching consensus now that impacts are going to be enough here--in the form of snow--to most likely at some point down the road req a WSW for the corridor and areas NW. Exactly what the totals are...probably too soon to say, but I sure do love the 00z runs coming in now. If I were a TV met this is when I'd start talking more substantively about the "potential". 

Is RPM an in house model? Is it available to public? Also what is the deal with the new parallel euro? It was a pretty big hit earlier today.

[Heisy]

1 hour ago, hazwoper said:

0Z NAM clown map paints 12+ Of frozen for SEPA.

Discuss

This storm should (crossing fingers) have a really fun 3-6 hours on the front end. 

[Moderately Unstable]

17 minutes ago, Wentzadelphia said:

Is RPM an in house model? Is it available to public? Also what is the deal with the new parallel euro? It was a pretty big hit earlier today.

It is an in house model. It's WSI's (the weather channel's parents') internal convection allowing high resolution model. They're also, fun fact, the one's developing deep thunder (aka graf)--which once operational will use a 15km grid, BUT, will have a 1 way 3 km upscaling in the conus--which they are suggesting will let them do away with convective parameterization (so that they can actually model individual thunderstorm cells). One way because those 3km cells won't then feed back out to the larger domain.  Basically the small cells get initialized by the boundary conditions of the larger domain (15km), then, operate independently. Now, if they're successful--this would be fantastic for mesoscale forecasting because it could (theoretically) enable one to almost predict in advance which cells would have sustained rotation with high accuracy and locational precision (SPC and NSSL toolsets allow for meso tracking already but it's more of a general "idea" than precise here at this time type of data...even though the output simulated radar sorta acts as though that isn't the case). But color me skeptical. They're working with IBM on this--I believe with a machine learning type of approach...in any case from what I've seen of the large domain GRAF so far, looks promising. Neither is available to the public (frankly it isn't even available to everyone in the private sector), and they're EXTREMELY protective of access to it, which is why I don't post the maps here. You can get in some actual trouble doing that. Like any model, it's guidance. But for whatever reason, it really is "worth" WSI's protectiveness...it's good. I've used it to chase individual thunderstorms before by using it to time out to a half hour interval where a particular cell would be and where. For mesoscale enhanced setups like this one, it tends to do a good job. 

 

WRT the || Euro, keeping up to speed on the rapid-fire-changes of the operational and ensemble guidance while checking model verification and current obs, and doing my day job...haven't had time to look at that today haha. Link?

 

[Heisy]

11 minutes ago, Moderately Unstable said:

It is an in house model. It's WSI's (the weather channel's parents') internal convection allowing high resolution model. They're also, fun fact, the one's developing deep thunder (aka graf)--which once operational will use a 15km grid, BUT, will have a 1 way 3 km upscaling in the conus--which they are suggesting will let them do away with convective parameterization (so that they can actually model individual thunderstorm cells). One way because those 3km cells won't then feed back out to the larger domain.  Basically the small cells get initialized by the boundary conditions of the larger domain (15km), then, operate independently. Now, if they're successful--this would be fantastic for mesoscale forecasting because it could (theoretically) enable one to almost predict in advance which cells would have sustained rotation with high accuracy and locational precision (SPC and NSSL toolsets allow for meso tracking already but it's more of a general "idea" than precise here at this time type of data...even though the output simulated radar sorta acts as though that isn't the case). But color me skeptical. They're working with IBM on this--I believe with a machine learning type of approach...in any case from what I've seen of the large domain GRAF so far, looks promising. Neither is available to the public (frankly it isn't even available to everyone in the private sector), and they're EXTREMELY protective of access to it, which is why I don't post the maps here. You can get in some actual trouble doing that. Like any model, it's guidance. But for whatever reason, it really is "worth" WSI's protectiveness...it's good. I've used it to chase individual thunderstorms before by using it to time out to a half hour interval where a particular cell would be and where. For mesoscale enhanced setups like this one, it tends to do a good job. 

 

WRT the || Euro, keeping up to speed on the rapid-fire-changes of the operational and ensemble guidance while checking model verification and current obs, and doing my day job...haven't had time to look at that today haha. Link?

 

Thanks for the info!

 WRT parallel euro, Someone linked it in the mid Atlantic forum earlier today, it had weatherbell graphics but I couldn’t locate it on the site... anyway...

Any idea why the Para GFS, 00z Ukie, and some others have a “snow hole” over Philly? Is it because we miss out on the waa fronto thump and the coastal snows just NW? Maybe the h7 low tracking too far inland? 

[KamuSnow]

5 hours ago, Wentzadelphia said:

Thanks for the info!

 WRT parallel euro, Someone linked it in the mid Atlantic forum earlier today, it had weatherbell graphics but I couldn’t locate it on the site... anyway...

Any idea why the Para GFS, 00z Ukie, and some others have a “snow hole” over Philly? Is it because we miss out on the waa fronto thump and the coastal snows just NW? Maybe the h7 low tracking too far inland? 

I took the reference to the para-euro as someone mispeaking, but maybe there is such a thing lol. I mean there could be, but not sure about publicly available. I am open to being enlightened.

[Ralph Wiggum]

6z para gfs

[The Iceman]

Mt holly first call... Looks good

 

[CoolHandMike]

Updated:

 

[penndotguy]

1 hour ago, Ralph Wiggum said:

6z para gfs

Love That map just wish it wasn't Kuchera,  Hoping we can send February out wit a bang

[MJO812]

[Snowcane21]

18 minutes ago, MJO812 said:

Each run continues to shift south. We have the reverse we’ve had all winter. Finally a strong  high pushing   NAM continues to adjust. 

[Ralph Wiggum]

6 minutes ago, Snowcane21 said:

Each run continues to shift south. We have the reverse we’ve had all winter. Finally a strong  high pushing   NAM continues to adjust. 

Actually vs 6z that ticked N and we are already seeing warmer low levels edging more N on some guidance. We know what to expect based on seasonal trends. This will be no different. Models likely overcompensated and are now going to begin adjusting N. Still think interior SE PA is a good spot for a hefty thump before flipping.

[Ralph Wiggum]

LV the hits keep on coming. This is your winter....enjoy!

[Snowcane21]

12 minutes ago, Ralph Wiggum said:

Actually vs 6z that ticked N and we are already seeing warmer low levels edging more N on some guidance. We know what to expect based on seasonal trends. This will be no different. Models likely overcompensated and are now going to begin adjusting N. Still think interior SE PA is a good spot for a hefty thump before flipping.

Definite tick South. 

[Ralph Wiggum]

2 minutes ago, Snowcane21 said:

Definite tick South. 

I was using snow depth maps where the s edge cut back slightly. I guess qpf max ticked s so neither of us is wrong depending on how u r looking at it.