December 2019 Med/Long Range Disco

[WxUSAF]

To me,  euro at 192hrs looks textbook classic for a I95 snowstorm except for the look over the Midwest. Bring a bit more high pressure over the lakes and plains and don’t have the northern stream wave try and phase in and it’s an absolute mauling.

[LP08]

1 minute ago, WxUSAF said:

To me,  euro at 192hrs looks textbook classic for a I95 snowstorm except for the look over the Midwest. Bring a bit more high pressure over the lakes and plains and don’t have the northern stream wave try and phase in and it’s an absolute mauling.

Here's the EPS.  Like you said, have a little more ridging or slow that NS SW down some and its a nice look.  Like the +PNA almost in the perfect spot poking up through Idaho.

 

 

[WEATHER53]

48 minutes ago, LP08 said:

Was just going to post this.  A perfect track Miller A but the High is already off the coast by the time it approaches us.  Let's NOT do this, haha.

Not all departing highs are equal. Some go out northeast or ene, this is more nne.  This is radiating down at  1028 mb, Vastly more helpful than a departing 1010

 

 

[WxUSAF]

Webb is onboard. The point of this is that a more southern stream only storm is less likely to get pulled inland up the TN valley or Apps and rain us.

 

[WxUSAF]

5 minutes ago, LP08 said:

Here's the EPS.  Like you said, have a little more ridging or slow that NS SW down some and its a nice look.  Like the +PNA almost in the perfect spot poking up through Idaho.

 

 

That’s a pretty nice look. If a piece of that Baffin Island vortex can reinforce some confluence and high pressure to our N and NW (it’s already there to our NE) were getting in a good spot.

[Bob Chill]

15 minutes ago, WxUSAF said:

Am I missing something when people say the shortwave hits Cali in 3 days? That’s the shortwave for the cutter and any possible anafrontal activity. Shortwave for next weekend doesn’t look like it comes onshore until like 5.5-6 days from now.

Speaking of the anafrontal wave, euro has it clearly but quite far south.

I was speaking about the euro run only. It's a different progression than the gfs. The euro focuses more on the lead shortwave that hits Cali in 3-4 days and lollygags from there. GFS is more progressive and focuses on the next one in line. No sense wasting a bunch of time discussing discrete pieces 6+ days out in time though.  

[WxUSAF]

5 minutes ago, Bob Chill said:

I was speaking about the euro run only. It's a different progression than the gfs. The euro focuses more on the lead shortwave that hits Cali in 3-4 days and lollygags from there. GFS is more progressive and focuses on the next one in line. No sense wasting a bunch of time discussing discrete pieces 6+ days out in time though.  

Yeah, I see that now. Fun to have a discrete window to track, even if the rug will probably get pulled on us by Sunday.

[psuhoffman]

4 hours ago, frd said:

 Reading some folks whom tie in the tropics with the HL, they state tropical forcing including AAM and GLAAM are lacking in terms of promoting the  mechanisms needed  to achieve  durable HL blocking, 

 

You seem to be in a dark place so I will throw out some numbers that might soothe the soul.

ESRL kept records on the GLAAM from 1958 to 2014.  They no longer update that.  There are places to get it but I just used those years of record.

In the last 50 years DCA has had 38 months with 6" or more of snowfall

The GLAMM was - 12 times, Neutral 14 times, and +12 times

DCA had 10" or more of snow 19 times

The GLAMM was - 6 times, Neutral 7 times, + 6 times.

There have been 17 seasons where 2/3 reporting stations had above normal snowfall during that period.

The GLAMM was - 6 times, Neutral 5 times, + 6 times.

Since 1950 the January/February months following a +AO December were

12 negative AO, 16 Neutral AO, 20 positive AO.  

 

[frd]

10 minutes ago, psuhoffman said:

You seem to be in a dark place so I will throw out some numbers that might soothe the soul.

ESRL kept records on the GLAAM from 1958 to 2014.  They no longer update that.  There are places to get it but I just used those years of record.

In the last 50 years DCA has had 38 months with 6" or more of snowfall

The GLAMM was - 12 times, Neutral 14 times, and +12 times

DCA had 10" or more of snow 19 times

The GLAMM was - 6 times, Neutral 7 times, + 6 times.

There have been 17 seasons where 2/3 reporting stations had above normal snowfall during that period.

The GLAMM was - 6 times, Neutral 5 times, + 6 times.

Since 1950 the January/February months following a +AO December were

12 negative AO, 16 Neutral AO, 20 positive AO.  

 

 

Thanks for taking the time to post that psu ! 

 

And, this is not as bad as I would have thought: 

Since 1950 the January/February months following a +AO December were

12 negative AO, 16 Neutral AO, 20 positive AO.  

 

 

[Bob Chill]

11 minutes ago, WxUSAF said:

Yeah, I see that now. Fun to have a discrete window to track, even if the rug will probably get pulled on us by Sunday.

CMC has the same shortwave as the euro but doesn't do anything with it. GFS is by far the most progressive. With pretty big differences through d5 on the gfs/euro/cmc, they all end up in the same general place d7-10. More questions than answers as usual. GEFS insists on more chances down the line so maybe it won't be as painful when the rug gets pulled. 

[frd]

@Bob Chill your call about the +PDO seems to be happening in real time. The November figure was positive. Of course we might improve on that this month.   

If this oceanic researcher is correct with his formula calculation,  then the PDO should rapidly increase in the + range later this month and in Jan. 

[Bob Chill]

22 minutes ago, frd said:

@Bob Chill your call about the +PDO seems to be happening in real time. The November figure was positive. Of course we might improve on that this month.   

If this oceanic researcher is correct with his formula calculation,  then the PDO should rapidly increase in the + range later this month and in Jan. 

Yes, it's been the only long range clue I've liked so far (other than the -AO that disappeared). Seeing the PDO shift positive and having split flow into NA isn't a coincidence. Unless blocking returns we're going to have to hang our whole wardrobe on the Pac helping us out in these parts. 

[cbmclean]

1 hour ago, psuhoffman said:

You seem to be in a dark place so I will throw out some numbers that might soothe the soul.

ESRL kept records on the GLAAM from 1958 to 2014.  They no longer update that.  There are places to get it but I just used those years of record.

In the last 50 years DCA has had 38 months with 6" or more of snowfall

The GLAMM was - 12 times, Neutral 14 times, and +12 times

DCA had 10" or more of snow 19 times

The GLAMM was - 6 times, Neutral 7 times, + 6 times.

There have been 17 seasons where 2/3 reporting stations had above normal snowfall during that period.

The GLAMM was - 6 times, Neutral 5 times, + 6 times.

Since 1950 the January/February months following a +AO December were

12 negative AO, 16 Neutral AO, 20 positive AO.  

 

I am having trouble finding information differentiating AAM vs GLAAM.  I know have seen GLAAM described as "Global Atmospheric Angular Momentum" and AAM as "Atmospheric Angular Momentum".  So what is the difference?

[frd]

Interesting, wonder what will happen when the  record +IOD starts to weaken or the Eastern region 1.2 becomes colder. I believe 1.2 is expected to get colder again later this month.  

Also, signs down the road the MJO starts to improve.  This may coincide with the next attempt of a - NAO , later in the month,  or early in Jan.  So, there is hope that both the Pac and the Atlantic may both become favorable for a time.  

 

 

[Bob Chill]

4 minutes ago, Ji said:

Ouch

Strong/organized storm = bad. No way around that except remarkable luck with every.single.feature

Oddly, the EPS shows the best chance for snow shortly after the front goes through next week. Didn't look into how they got there but around 25% of the eps members drop snow thurs/fri. Could be anafrontal or could be the trailing southern shortwave. Not sure. EPS doesn't like the followup event. Mostly rainers. 

 

[Bob Chill]

All rain from this in mid december? Lol. 

[Ji]

3 minutes ago, Bob Chill said:

All rain from this in mid december? Lol. 

This looks just like the near miss storm from last mid December 

[Rhino16]

2 minutes ago, Ji said:

This looks just like the near miss storm from last mid December 

The one from the like 9-10th? I’ll take one of those again!

[Bob Chill]

Just now, Ji said:

This looks just like the near miss storm from last mid December 

We generally score 1 out of 4 legit chances so we're getting a few misses out of the way quickly. 

[Ji]

1 minute ago, Rhino16 said:

The one from the like 9-10th? I’ll take one of those again!

No there was a massive storm a few days later. Great upper low pass but it was all rain. I think it was also on a Saturday

[MJO812]

26 minutes ago, Bob Chill said:

All rain from this in mid december? Lol. 

Ensembles are much better

[jaydreb]

GEFS clown maps.  

 

[WxUSAF]

18z GEFS again more bullish on the anafrontal snow chance it seems.  

[stormtracker]

28 minutes ago, Ji said:

No there was a massive storm a few days later. Great upper low pass but it was all rain. I think it was also on a Saturday

Hope you like valley livin

[Bob Chill]

3 minutes ago, losetoa6 said:

Latest Gefs has lots of anafrontal hits overall ranging from southeast forum hits , a couple flush central Md hits and a few west of Frederick maulers Mainly for Wed into Thursday am looking at members . The threat is alive and well ...good tracking ahead

 

Ninjd ..

I'm a slow typer lol

Maybe we're looking too far down the road? Very complicated flow coming up starting middle next week. I'm expecting lots of twist and turns. Just don't have a feel if the turns will be good or not... 

[osfan24]

Can anyone recall when we got snow, particularly significant snow, from an anafrontal? I feel like these are always huge teases and never work out. 

[WxUSAF]

1 minute ago, osfan24 said:

Can anyone recall when we got snow, particularly significant snow, from an anafrontal? I feel like these are always huge teases and never work out. 

When we actually get snow from these, it's not really anafrontal. The nomenclature gets a bit muddled.  It's really a weak wave along the front.  And from those, we get snow fairly often.  A wave along the front is what we're really looking for.  

[Bob Chill]

7 minutes ago, losetoa6 said:

Yep...your right and usually all that's needed is a lil blip of a wave not much at all and definitely hard for globals to pin down past 72 hrs . Many in the past have been short range little surprises we back into.  Usually good for 1-3 2-4.  I believe 2013 we had a couple 

13/14 had like 6 or even more. It was remarkable how many worked out. We started expecting them and we can literally go multiple years without getting hit like that. Southern stream is active now. You can see the connection all the way west of Baja with the front.

 

I'll have to look at ens members and see what's different with the frontal wave solutions that snow but my guess is the front stretches more E-W instead of vertical. You can see that alignment on the gefs member snow maps. 

[Bob Chill]

8 minutes ago, losetoa6 said:

@Bob Chill .....Remember when Nam scored a big coup on that 1 from 2013/14 . It sniffed it from 84 hr lol

 

Ukmet at 144 looks like a possible hit to me ..limited maps but its post frontal 

 

We can work with this spread. Couple look just like the ukie. Becoming more interested in this...

[WxUSAF]

Very long range, one feature to maybe keep an eye on is the poleward oriented ridge over the Urals that Eps and GEFS show well established by D10. GEFS retrogrades it toward Scandinavia by the end of the run. This might be what HM is cryptically referring to as the next -NAO precursor.