December 2019 Med/Long Range Disco

[CAPE]

1 minute ago, psuhoffman said:

The Australian hasn’t been updated since February 

How about the Panasonic?

[Ralph Wiggum]

Unfortunately Bob is right (which is usually more often than not). There is a flat and fast flow coming up with a flood of PAC maritime air poised to invade N america and is under 10 days. 

However, I am still a believer this is a relatively brief relax in the overall  pattern. The effects of the PAC puke pattern will be felt just before Christmas it appears. It is what it is. So we wont have to bundle up like eskimos to visit the fam. I can deal with that....we are used to it by now right? But temps as folks noted wont be 60s and 70s but more of a muted torch with mid 40s and 50s likely being the extreme.

With that said, there is already light at the end of the tunnel(if the LR GEFS are to be believed) and by 240 hours a broad trof is already starting to develop with more of an amplified flow out West and less of a direct PAC maritime influence. Rather than post the 500mb maps (leaving that to @showmethesnow ) I am posting the 2m anomalies to simplify things for folks that are already panicking. Here is the 5-day 2m temp anomalies loop for the 18z GEFS run. 2m is difficult.to forecast but is reflective of the pattern moderation breaking down. At 240 you can see the wave of PAC air flying thru the US from W to E. However there are 2 things that stand out....first is the BN air replacing the PAC air out in w Canada and the US but also the AN temps progressing into Greenland. If the flow is to be believed, the moderation will be short-lived and warmth over Greenland generally spells ridging in that area as far as I'm concerned. Sticking to the moderation being roughly 6 or 7 days with the reload being in place by New Years. Probably wrong and tough to call but I figured why not try. If past history this early season is indicitave of length of pattern reload, it should be relatively brief.

[cbmclean]

32 minutes ago, psuhoffman said:

The Australian hasn’t been updated since February 

Ah I did not notice that.  Maybe it had to shut down when some of the members started breaking outside the freaking box.

[psuhoffman]

2 hours ago, C.A.P.E. said:

I see it. Its a high amped, fast/progressive pattern. I wish people would stop using the term "blocking" every time they see a blob of red on an h5 panel in the "right place" that lasts a few hours.

 

That is NOT a block. We are seeing the opposite of a blocked flow now, and also going forward (advertised) in the LR.

I agree completely with the first part. But I’m not sure I agree with the second. Since March of 2018 we haven’t had any real -NAO blocking. We had some bootleg transient ridges as a tpv lobe traversed a location to promote a short lived ridge there.  But what’s coming up seems like a classic west based -NAO episode. It also seems likely it gets muted for a while by as hostile a pac as we could have. 

The -NAO actually begins in only 24 hours as the current wave breaking near 50/50 builds a ridge over the top that links with the current epo side block.  By 48 hours it’s a classic west based -NAO with 50/50 low representation.

2 days later even a stronger west based -NAO representation.  And it is “blocking the flow”  despite a raging fast pac jet and gulf of Alaska vortex the next wave is being blocked under and is about to become the next 50/50 low.  That’s a classic evolution.  Lower heights exist in the means there because in a -NAO every wave gets forced under through that domain.  But one system doesn’t just sit there for weeks on end. If it did we would just be frigid cold and bone dry.  

A day later (now 4 days unto the -NAO) and we still have a classic ridge over low representation but the pacific problem is rearing its head.  That isn’t just a bad pac, it’s atrocious!  That gulf of Alaska vortex is pumping a ridge into central NAM.  The blocking isn’t breaking down but the central N Am ridge is going to merge and get absorbed which severely muted its effect.  

But even with that, it still manages to force the next wave under us!  With that pacific look that storm should cut to Hudson Bay!  If you want to know what our weather would look like without a -NAO with that pac just go back to December 2015.  The pattern over the east is blocked, that’s how a system gets suppressed south of us despite a vortex on the west coast.  It’s just not going to be able to completely offset a record pac jet in an awful alignment.  

At this point we’re 11 days unto the -NAO and the pac jet has cut underneath as soon as the vortex off the west coast relaxed some as is typical in a -NAO.  The pac is still bad just not the absolute dumpster fire it was.  This is still a classic west based -NAO with lower heights through the 50/50 space through the 11 days.  Who knows if it’s even right this far out but the representation is classic blocking regime imo.

Now at day 15 it’s evolved into an east based block.  Ironically the NAO index will be more negative now since its calculated at Iceland.  But again who knows if it’s right and the monster Scand ridge would imply we likely cycle back into blocking not break down.  

The look past day 5 could be BS.  But what we see on guidance is classic -NAO imo.  It’s muted by other hostile factors. We went through a similar problem towards the start of the last great blocking period in Feb into Mar 2018.  We suffered a perfect track rainstorm then a couple near misses due to an imperfect trough axis because of a less ideal Pac.  Then a storm got suppressed. It was during the second cycle or pulse of the NAO that we finally got a nice snowstorm in late March.  No idea how this will play out. But I do think this is finally a real -NAO. But that doesn’t mean we get snow.  We had a real -NAO most of the winter of 2000/2001 without much to show because of a not ideal pac.  December 2001 had a great NAO block the pac ruined.  It’s hapoened before. 

[leo2000]

3 hours ago, C.A.P.E. said:

Problem here is there really is no  NA blocking and that impressive 50-50 races away into the NA. That is the general problem when there is no legit block. Transient higher h5 heights in the NAO domain do not qualify as a block. It can work,  but It is temporary and requires damn near perfect timing.

 

3 hours ago, Bob Chill said:

If we get perfect track/blocked storms that are all rain i'm gonna be pissed. The Pac onslaught is real on this panel. Above freezing 850s all the way to the Yukon... wtf man

Not in my area lol. 

[Maestrobjwa]

3 hours ago, Bob Chill said:

If we get perfect track/blocked storms that are all rain i'm gonna be pissed. The Pac onslaught is real on this panel. Above freezing 850s all the way to the Yukon... wtf man

Bob, it's the last week of December...so that's almost guaranteed to happen that week, lol (doesn't snow significantly during that week or the next around here!)

[leo2000]

45 minutes ago, leo2000 said:

 

Not in my area lol. 

Doesn't seem to have any real support from the GEFS as well as the CFS weekly and the GEPS. 

[Amped]

GFS trying real hard this run.  

Edit probably going to get NC and Richmond. Took a sharp right after hr 156

[Buddy1987]

1 minute ago, Amped said:

GFS trying real hard this run.  

Gonna go with the ole major convective feedback issues looking at surface with that low. Good thing is it's there. 

[jaydreb]

Congrats SC.  

[Amped]

3 minutes ago, Buddy1987 said:

Gonna go with the ole major convective feedback issues looking at surface with that low. Good thing is it's there. 

That was a nasty dive. The ULL went north of STL, then still went over Jacksonville. 

Edit so does the surface low. Forms near Wilmington then Drops south from 180 to 192,  One of the most bizarre runs I've seen.

[psuhoffman]

27 minutes ago, Amped said:

GFS trying real hard this run.  

Edit probably going to get NC and Richmond. Took a sharp right after hr 156

Too much blocking. The high lat ridge is centered closer to the east shore of Hudson Bay than Greenland. That “can” work but it does open the door to suppression. On top of that the tpv near 50/50 pinwheels a lobe down at the exact wrong time to flatten the flow on top of it. That could change over 7 days. 

[stormtracker]

Too much of a good thing on the GFS

[stormtracker]

Ninja'd

[nj2va]

At least its something to track vs talking about PAC puke.  I’m fine with where things are a week out.

[stormtracker]

Just now, psuhoffman said:

Too much blocking. The high lat ridge is centered closer to the east shore of Hudson Bay than Greenland. That “can” work but it dies open the door to suppression. On top of that the tpv near 50/50 pinwheels a lobe down at the exact wrong time to flatten the flow on top of it. That could change over 7 days. 

Remember when we didn't have good blocking like 24 hours ago?  

[Buddy1987]

Just now, Amped said:

That was a nasty dive. The ULL went north of STL, then still went over Jacksonville. 

Thing basically goes under bombogenesis from 168-180 goes from like 1001 to 981. You would think CCB would be for real on the NW side with a storm strengthening that much off MYR. 

[JakkelWx]

2 minutes ago, Amped said:

That was a nasty dive. The ULL went north of STL, then still went over Jacksonville. 

That ULL was real close to becoming a Jan 2016 type deal. Unfortunately it's congrats South Carolina on your white Christmas. Other than that it's a classic setup with just needing a couple tweaks.

[Buddy1987]

I dont see how we all dont feel at least somewhat positive with how consistent this has been with support of the ensembles as well. Def a somewhat wonky run with what the low does and the ull crashes down like a roller coaster leaving its highest point. At least for me where I'm sitting right now storm going boom right off MYR makes me excited.

[cbmclean]

13 minutes ago, JakkelWx said:

That ULL was real close to becoming a Jan 2016 type deal. Unfortunately it's congrats South Carolina on your white Christmas.

I haven't actually looked at the runs so forgive the question if its stupid, but no matter how perfect the track and how strong it gets, won't it be too warm for anything frozen? 

[psuhoffman]

23 minutes ago, stormtracker said:

Remember when we didn't have good blocking like 24 hours ago?  

Lol. Well without that extreme blocking with what the pac looks like that storm would cut so hard Santa might have issues launching his sleigh in all the rain. 

[Amped]

CMC has a low over hudsons bay. Not a hit unless it digs as fast as the GFS. J/K

[psuhoffman]

CMC is weaker with the energy ejecting from the pac trough then washes it out into the central US ridge. Nothing survives to the east coast. 

[yoda]

Here is 00z UKIE at 120 and 144

 

[psuhoffman]

^that ain’t gonna work 

[stormtracker]

39 minutes ago, yoda said:

Here is 00z UKIE at 120 and 144

 

trash

[yoda]

I'd say 00z Euro was a step in the right direction if we want a storm next weekend 

[Amped]

Euro gives us some snizzle.  A decent hit for  Eastern New England.  

It now has a 950mb low south of Nova scotia where there was nothing yesterday.

[yoda]

10 minutes ago, Amped said:

Euro gives us some snizzle.  A decent hit for  Eastern New England.  

Funny it now has a 950mb low south of Nova scotia where there was nothing yesterday.

Decent hit?  Lol... it's a crushing in SNE

ETA: misses NYC too lol

[Ralph Wiggum]

6z GFS was a step in the right direction: