January Medium/Long Range Disco Thread

[psuhoffman]

GFS op recycles the blocking...this second iteration is actually more ideally located and configured.  It’s fantasy land but I do agree with the idea the blocking likely recycles several times before breaking down. 

[PCT_ATC]

1 hour ago, NorthArlington101 said:

As per a request...

 

Add Sun Angle and DC Snow Hole please

 

[psuhoffman]

I do think suppression is a legit risk until we see the blocking relax some. It’s a beast and centered pretty far south. That panel at the end of the GFS with a closed Rex block centered over Baffin is more where we want a strong block configured and located. That big elongated w-e block centered all the way down into Quebec could set up a shred factory flow over the US for a while.  It won’t last forever though and as it relaxes we have a window and if it does reform further north we could have an extended window later. 

[Baltimorewx]

14 minutes ago, psuhoffman said:

I do think suppression is a legit risk until we see the blocking relax some. It’s a beast and centered pretty far south. That panel at the end of the GFS with a closed Rex block centered over Baffin is more where we want a strong block configured and located. That big elongated w-e block centered all the way down into Quebec could set up a shred factory flow over the US for a while.  It won’t last forever though and as it relaxes we have a window and if it does reform further north we could have an extended window later. 

Kinda sucks though for the blocking to be that strong yet, its really not all that cold and still somewhat of a thread the needle airmass even if a storm came up...

[WxUSAF]

I think Friday is about forked.  Euro moved back south.  Congrats NC.  

[WinterWxLuvr]

Deep vortices  over the northeast tend to lift out more quickly than modeled. These are actually further northeast but it’s that action that is messing up our system this week. Move those out a bit quicker and the game changes.

[SomeguyfromTakomaPark]

Just now, WxUSAF said:

I think Friday is about forked.  Euro moved back south.  Congrats NC.  

Pretty anemic for everyone outside the mountains of western NC.  We're not going to be missing much with this one. 

[WinterWxLuvr]

72 hours is a long time in a delicate setup

[PivotPoint]

2 hours ago, psuhoffman said:

There is always that risk in a blocking regime but you have to remember we are too far south for most patterns to work. Absent blocking to suppress the flow we are usually south of the storm track.   But take Friday for example. The issue is the blocking is a bit too strong and centered too far south. The ensuing trough in the east gets centered south of ideal. You can see on the means this week the west to east “blue” is a bit south of that “big snow” plot I posted. But if the track was further north we would be just fine. The few runs that did show snow for us were mostly west to east systems too...just they came west to east just under us instead of way down in the Deep South.   But it’s unlikely the blocking stays at the current really ridiculous levels. It will wax and wane and during those relaxations we could get a system to gain a bit more latitude or come west to east at a higher latitude. Take that storm that fringed us on the long range GFS last night. That gained no latitude at all. It moved straight west to east but if it comes across 50 miles more north we get a HECS.  PD2 was like that. It moved straight w-e until it hit the coast then gained some latitude but not much.  PD1 1979 also.  We also could get a storm that gains some latitude with a temporary relax that won’t show on a 7 day mean. The slight one day ridging ahead of the storm is washed out on means by the N flow behind the storm.  We don’t need a lot of latitude gain. Our ideal track is a primary to TN then jump to NC coast and a latitude gain to about Ocean City. From there ideally we want it to move east.  
 

That said the building positively tilted western PNA EPO ridge later in the period does add more threat of suppression.  January 1977 featured that look and it was arctic cold but bone dry.   That’s going to flood cold into the CONUS and suppress the baroclinic zone way south. So yea that’s a threat.  
 

But now I’m honestly getting frustrated and here is why. A week ago when the blocking showed but there was still a N PAC trough and not a lot of PNA and no EPO all the debs were saying “but it’s not cold enough in that look we would need a perfect track”. And now that the EPO/PNA ridge goes up it’s “but that could be suppressive”. Ok well what do you freaking want?  Those two things are mutually exclusive. You have to dance with one of those devils.  Our HECS look actually has less PNA EPO for the very reason you just said. But it’s not a cold pattern and sometimes it’s not cold enough and we get a perfect track cold rain. The epo ridge -NAO is a cold pattern but dryer and sometimes we don’t get any big juiced up coastals.  No pattern is 100% fool proof guaranteed to snow.

There’s some good points in there. I think one of the ones I find pertinent is the angle of PNA ridge and that lending to suppression. We’d ideally like that to have a more negative tilt to allow any sw that gets under us to gain latitude without the PNA punting is into a huge block and then OTS. Good points 

[aldie 22]

6 minutes ago, WxUSAF said:

I think Friday is about forked.  Euro moved back south.  Congrats NC.  

This one never really had that feel, we went straight into hoping things would trend mode and never really had a solid hit. This one doesn't really feel like a loss to me. On to the next opportunity! That said I wasn't going to bail until 0z tomorrow so I'll hang in there

[frd]

24 minutes ago, psuhoffman said:

t won’t last forever though and as it relaxes we have a window and if it does reform

March will rock !         

  j/k

[Scraff]

7 minutes ago, WxUSAF said:

I think Friday is about forked.  Euro moved back south.  Congrats NC.  

I’m looking for the WxUSAF storm more importantly. 

[psuhoffman]

1 minute ago, WxUSAF said:

I think Friday is about forked.  Euro moved back south.  Congrats NC.  

I’ve kinda felt it was forked when all the guidance shifted the H5 track from across VA to across NC a while ago. The N trend we often observe the final 72 hours is not typically from a huge shift in the major synoptic features like the h5 track. It’s mostly due to the fact that globals tend to underestimate the north extent of mid level warm air intrusion and thus they also underestimate the NW expanse of moisture transport and WAA lift in the commahead.  They tend to expand that significantly in the end and that mid level warm intrusion also shifts the mix area north. But this isn’t the right setup for that without any deep cold around.  There is “some” typical last minute latitude gain of the surface low but it’s not usually that significant.  Based on these observed model biases our sweet spot at 72-144 hours out is to have the heavy snow centered just south of us. Like central VA and lighter snows up into our area. Something where a 50 mile shift matters. Once we start seeing the action shift into NC inside 144 hours it’s usually over recently. That’s felt like the way these play out the last decade or so.  

[osfan24]

2 minutes ago, Scraff said:

I’m looking for the WxUSAF storm more importantly. 

Agreed. Friday wasn't a big deal to me at all. Early next week is where my focus is.

[yoda]

h5 looks much better to me on today's 12z EURO compared to yesterday's 12z EURO FWIW I think

[WxUSAF]

Not sure if the euro is going to get there, but the 500mb look through 144hrs is MUCH improved over 0z.  Much less sheared/progressive. Neutrally-tilted trough along the MS valley at 144.  

[Amped]

If you thought the GFS's 500mb height surface low was a mismathch,, wait until you see the Euro.

 

 

 

[Eskimo Joe]

41 minutes ago, psuhoffman said:

GFS op recycles the blocking...this second iteration is actually more ideally located and configured.  It’s fantasy land but I do agree with the idea the blocking likely recycles several times before breaking down. 

Notice how the Pacific ridge is actually here, we almost get some cross polar flow here so temps won't be an issue with any storm that we get.

[psuhoffman]

2 minutes ago, WxUSAF said:

Not sure if the euro is going to get there, but the 500mb look through 144hrs is MUCH improved over 0z.  Much less sheared/progressive. Neutrally-tilted trough along the MS valley at 144.  

There is much less of a suppressive flow in the way of that wave. But it’s also more complicated then the fairly simple bowling bowl system this week. Need multiple parts to phase. If they do it will come north though. It’s always something lol. 

[WxUSAF]

Oh baby, incoming on the euro

[WxUSAF]

Just now, psuhoffman said:

There is much less of a suppressive flow in the way of that wave. But it’s also more complicated then the fairly simple bowling bowl system this week. Need multiple parts to phase. If they do it will come north though. It’s always something lol. 

Yeah, it's a phasing situation.  Which opens the door to big dog potential, but it's a complicated pattern with so many shortwaves flying around.  

[JakkelWx]

 

[Scraff]

Just now, JakkelWx said:

 

 JI will still complain 

[LP08]

Blue!

[NorthArlington101]

[Ji]

Just now, Scraff said:

 JI will still complain 

works for me

[Ji]

1 minute ago, LP08 said:

Blue!

blue baby! 

[WxUSAF]

@CAPE hates it verbatim, but it's a great run.  No one should whinge about the r/s line at D7.  1'+ for the western DC burbs.  

[jaydreb]

Whoa there Euro!  

[NorthArlington101]