Mid January/Mid February Medium/Long Range Discussion

[Ji]

I still don't think the final outcome for Saturday is going to be determined tonight. This comes back imo...seen it happen several times

[Bob Chill]

2 minutes ago, Ji said:

I still don't think the final outcome for Saturday is going to be determined tonight. This comes back imo...seen it happen several times

Agree. Writing something off this far away is dumb. These all or none everything perfect setups are getting tiresome though. No wiggle room ever this year. The gfs just repo'd the 36 hour storm to add more salt to our wounds

[Bob Chill]

Lol poor Loudon. I'll cherish my .1"

[Ji]

Lol poor Loudon. I'll cherish my .1"

Lol the feb 8 storm looks like the feb 1 storm when feb 1 had a storm

[Ji]

Gfs took 20 from me...I'm out. I really think we are destined to get shutout

[Ji]

If you add up snow for dc metro between tonights gfs and ggem....we got a combined 0 inches...during the best pattern of the year

[Jrlg1181]

1 minute ago, Ji said:

If you add up snow for dc metro between tonights gfs and ggem....we got a combined 0 inches...during the best pattern of the year

I tend to agree , at least I got 4 a couple weeks ago , not sure how much you guys got.... But it only takes 1 storm to make us all happy.... We are like a football team trying to sneak into the playoffs at 9 & 7 and who knows what happens if we do..... Time is running out but we still have a chance....But If I win the mega millions I most certainly am moving to Maine or the Rockies.....

[Ji]

Hmm

[Ji]

I think models are keying in more on the diving northern stream shortwave

[psuhoffman]

1 hour ago, Ji said:

I think models are keying in more on the diving northern stream shortwave

If it’s goinf to work it almost has too phase with one of them clean. There is a train of NS shortwaves flying across keeping the flow flat over top of it. Unless it hitches it’s wagon to a NS wave that digs enough to capture its in trouble. Perhaps if the stj wave ejected whole but the ships sailing on that and its circular thinking. The progressive flow shearing the top of the stj wave is what causes the reaction of the wave stretching and leaving too much energy behind in Mexico. 

[BristowWx]

Just now, psuhoffman said:

If it’s goinf to work it almost has too phase with one of them clean. There is a train of NS shortwaves flying across keeping the flow flat over top of it. Unless it hitches it’s wagon to a NS wave that digs enough to capture its in trouble. Perhaps if the stj wave ejected whole but the ships sailing on that and its circular thinking. The progressive flow shearing the top of the stj wave is what causes the reaction of the wave stretching and leaving too much energy behind in Mexico. 

Maybe we could sneak in some flakes Sun am from that ns shortwave like 6z shows. 850s look good. Still shows RN right now

[psuhoffman]

5 minutes ago, BristowWx said:

Maybe we could sneak in some flakes Sun am from that ns shortwave like 6z shows. 850s look good. Still shows RN right now

Maybe. Trying to figure out specific details of NS vorts in a progressive flow is difficult at 48 hours. At 6 days forget it.  

[CAPE]

49 minutes ago, psuhoffman said:

If it’s goinf to work it almost has too phase with one of them clean. There is a train of NS shortwaves flying across keeping the flow flat over top of it. Unless it hitches it’s wagon to a NS wave that digs enough to capture its in trouble. Perhaps if the stj wave ejected whole but the ships sailing on that and its circular thinking. The progressive flow shearing the top of the stj wave is what causes the reaction of the wave stretching and leaving too much energy behind in Mexico. 

Still plenty to be worked out with phasing/lack thereof, track etc. One thing that continues to be consistent though is the complete lack of arctic air. Only way it works imo is a perfect phase/perfect track and a robust deformation zone. My interest lies in the period just beyond when it appears we will finally have some decent cold air to work with, and maybe even a transient -NAO.

[psuhoffman]

48 minutes ago, C.A.P.E. said:

Still plenty to be worked out with phasing/lack thereof, track etc. One thing that continues to be consistent though is the complete lack of arctic air. Only way it works imo is a perfect phase/perfect track and a robust deformation zone. My interest lies in the period just beyond when it appears we will finally have some decent cold air to work with, and maybe even a transient -NAO.

Yep...that period continues to hold promise. 

But let’s say we don’t get lucky in that window...and it goes to this...

-epo,-AO, -NAO and a raging southeast ridge lol. 

That looks like the conflict beteeen the dueling convection in the IO and west pacific. We get the high lat response of the IO wave but also the Se ridge of the pac wave.  That would be the final kick to the Nads from this winter!

i suppose on the optimistic side if the se ridge gets suppressed in that look it sets up a prettt epic boundary wave pattern  

 

[frd]

1 minute ago, psuhoffman said:

That looks like the conflict beteeen the dueling convection in the IO and west pacific.

I really hope the later season IOD influence is cold as it should be,  not some nutty new thing. 

[Round Hill WX]

It is going to be very difficult to achieve the type of storm we need to get snow with this 250mb jet just racing zonally. No way to bomb and turn up the coast. 

[psuhoffman]

31 minutes ago, frd said:

I really hope the later season IOD influence is cold as it should be,  not some nutty new thing. 

My guess is if we don't get cold it will have to do with the IO forcing being offset by the unfavorable forcing in the west pacific where convection continues to want to reform around phase 6.  

[Weather Will]

Since the probability maps through Day 16 seem to cause so much agitation, I will only show them through Day 5 for now on.  Much more realistic.  WB EPS 6z. 

[psuhoffman]

@frd that GEPS day 16 I posted as a joke does look like what you would get if you mashed phase 2 and phase 6 together in February...  We need to hope that the phase 6 wave relaxes enough to let the IO forcing become dominant at times.   My guess is if they both offset we get a blah pattern...not totally god awful but probably not good enough.  What doesn't help is I suspect the mjo pac forcing is more strongly correlated to our pattern than the IO forcing...I would rather a favorable wave in the PAC phase 8/1 offsetting an unfavorable one in the eastern IO than the other way around...

[das]

14 hours ago, WinterWxLuvr said:

For all intents and purposes every one of these maps you post, no offense to you, look exactly the same.

And look suspiciously like, wait for it, climatology.

[psuhoffman]

44 minutes ago, Weather Will said:

Since the probability maps through Day 16 seem to cause so much agitation, I will only show them through Day 5 for now on.  Much more realistic.  WB EPS 6z. 

They actually do have "SOME" usefulness but the issue is they highlight how much we suck at snow and no one wants that thrown in their face EVERYDAY.  But they do show what our chances are with respect to "climo".  Problem is...when the mean shows about 30% chance of snow over 15 days...especially when it all comes in a 5 day chunk...that is actually an above normal chance of 3" of snow for DC.

I broke down the period from Dec 1 to Mar 15 into roughly 15 day chunks... I basically split each month in half... doing that gives us 210 roughly 15 day periods...and DC got 3" of snow 42 times in those 210 periods...so that is about 20% of the time.  So when we have a 30% chance of 3" of snow that simply tells us we have a slightly better than normal chance at 3" of snow.  When we see those means get up above 50% that is REALLY good compared to avg.  Problem is our average is no snow...80% of the time we go a 15 day period in winter without 3" of snow so...that is just normal.  But we do sometimes see that mean near 0% and that tells us its almost a no hope shut out the lights pattern the next 2 weeks... and we get a lot of those. 

Here is the breakdown in terms of DC odds of seeing 3" of snow during a period in the last 30 years

Dec 1-15           13%

Dec 16-31         6%

Jan 1-15           13%

Jan 16-31         33%

Feb 1-14           27%

Feb 15-28/29  23%

Mar 1-15          23%

[Ralph Wiggum]

1 hour ago, psuhoffman said:

Yep...that period continues to hold promise. 

But let’s say we don’t get lucky in that window...and it goes to this...

-epo,-AO, -NAO and a raging southeast ridge lol. 

That looks like the conflict beteeen the dueling convection in the IO and west pacific. We get the high lat response of the IO wave but also the Se ridge of the pac wave.  That would be the final kick to the Nads from this winter!

i suppose on the optimistic side if the se ridge gets suppressed in that look it sets up a prettt epic boundary wave pattern  

 

Nao seems transient during this period which was a concern going in (that is IF we even progress to a -NAO which signs still point to yes for now). But as I've said a few times, this is one of the better potential windows we've seen this winter so get one or 2 chances over a 5-8 day stretch and I will roll the dice with that given the calendar date. We have done half decent with window opportunities this year, so let's give it another go.

[WinterWxLuvr]

20 minutes ago, das said:

And look suspiciously like, wait for it, climatology.

Exactly and therefore serve absolutely no purpose 

[psuhoffman]

24 minutes ago, WinterWxLuvr said:

Exactly and therefore serve absolutely no purpose 

They are serving a purpose though...they have been telling us our chances of snow are not good...and guess what...they havent been.  When/if the pattern gets better those maps will show a better probability.  Just because its depressing to see that our chances suck everyday doesn't make the information useless.  

However... @Weather Will I have noticed that over the last couple weeks...when we get the rare good run of a model somehow you forget to post that...its not fair to post all the dreadful ones and then not post when something good pops up...like last nights 0z GEFS run which was littered with hits day 10-15.

  I know 6z backed off but if we start to see more runs like this it could be a sign that our prospects are improving..especially since the look coincides with a better h5 pattern being progged.  

[WinterWxLuvr]

Just now, psuhoffman said:

They are serving a purpose though...they have been telling us our chances of snow are not good...and guess what...they havent been.  When/if the pattern gets better those maps will show a better probability.  Just because its depressing to see that our chances suck everyday doesn't make the information useless.  

However... @Weather Will I have noticed that over the last couple weeks...when we get the rare good run of a model somehow you forget to post that...its not fair to post all the dreadful ones and then not post when something good pops up...like last nights 0z GEFS run which was littered with hits day 10-15.

  I know 6z backed off but if we start to see more runs like this it could be a sign that our prospects are improving..especially since the look coincides with a better h5 pattern being progged.  

You could post that map for any 15 day period from mid December to mid February and those are probably pretty close to our chances all the time. 
 

The maps he’s posting rarely change, perhaps a 10-20% swing. 
 

If you want to base your thoughts on whether we get x amount of snow over a 16 day period based on that then go right ahead. I guess you can manufacture stats to back you up. But I’ll bet if you could somehow get the snowfall totals for any 16 day stretch over the past 50-100 years for any location on that map that those stats will match that map pretty closely.

[clskinsfan]

3 minutes ago, WinterWxLuvr said:

You could post that map for any 15 day period from mid December to mid February and those are probably pretty close to our chances all the time. 
 

The maps he’s posting rarely change, perhaps a 10-20% swing. 
 

If you want to base your thoughts on whether we get x amount of snow over a 16 day period based on that then go right ahead. I guess you can manufacture stats to back you up. But I’ll bet if you could somehow get the snowfall totals for any 16 day stretch over the past 50-100 years for any location on that map that those stats will match that map pretty closely.

I tend to agree with you. A 50% chance of 3 inches of snow through mid Feb for our area would be normal.

[psuhoffman]

6 minutes ago, WinterWxLuvr said:

You could post that map for any 15 day period from mid December to mid February and those are probably pretty close to our chances all the time. 
 

The maps he’s posting rarely change, perhaps a 10-20% swing. 
 

If you want to base your thoughts on whether we get x amount of snow over a 16 day period based on that then go right ahead. I guess you can manufacture stats to back you up. But I’ll bet if you could somehow get the snowfall totals for any 16 day stretch over the past 50-100 years for any location on that map that those stats will match that map pretty closely.

They have looked very similar a LOT lately because we have spent a LOT of time in the same general pattern (SUCK) lately.   But we have had times when we are above 80% on those probability maps (other then when there is a storm like right in front of us and its 100% but that is like DUH) but those were typically periods when we were legitimately about to get slammed like in 2014 or from range before January 2016.  I also think there were some pretty good looking probability maps before the run we had in Late Feb into Mar 2015.  I also remember seeing some pretty good probability maps when the blocking started in March 2018.. and guess what...all those were times where we actually DID snow.  But like I pointed out above 80% of the time in the winter we do NOT get 3" of snow in a 15 day period so if those maps are close to accurate...80% of the time they SHOULDNT show a high probability of snow.  So yes MOST of the time they will look pretty sucky because most of the time our snow results will be pretty sucky.  The rare times when a legit good pattern is coming you will see those probability maps increase.  Look at the one I posted from last night.  If we start to see maps like that for multiple runs (with above 50% prob) on the GEFS/GEPS/EPS then we know our odds are improving and that is useful.  

ETA:  I am not saying a snow mean or probability map is the best way to analyze the pattern but those maps have SOME limited usefulness in terms of getting a general sense of what the guidance thinks our odds are in the next 2 weeks.  Thats all...

[Weather Will]

They are serving a purpose though...they have been telling us our chances of snow are not good...and guess what...they havent been.  When/if the pattern gets better those maps will show a better probability.  Just because its depressing to see that our chances suck everyday doesn't make the information useless.    EXACTLY  WHY I SHOW THEM.....thanks PSU.

 

[87storms]

1 hour ago, Round Hill WX said:

It is going to be very difficult to achieve the type of storm we need to get snow with this 250mb jet just racing zonally. No way to bomb and turn up the coast. 

yea, i thought the canadian has handled this system pretty well.  a few days ago it was showing the potential for a flatter system/less phasing with the trough being too far east.  

[psuhoffman]

3 minutes ago, clskinsfan said:

I tend to agree with you. A 50% chance of 3 inches of snow through mid Feb for our area would be normal.

Yea but if we look at the pattern for the whole 15 day period that map covers...it is about "normal"  The first 7 days are god awful for snow...with some lottery ticket super phase bomb scenario being the only chance, then after that a warmup as a trough dumps into the central US initially...then it gets good day 10-15...but only 5 of the 15 days have a good pattern...the other 10 are crap...so overall that washes out to about an "average" chance of 3" and since for that period you probably get 3" about 50% of the time...that seems about right...I would say that probability fits the pattern I am looking at pretty good.   I think those probability maps have actually been about what they should be given the patterns...so not sure what all the fuss is about.