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Model Mayhem V


Typhoon Tip

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Entertainment run amok!  

Last week, then over night last night, now this almost 'too good to be true' clip blizzard for eastern New England Monday morning,.. then, a planetary signal for Thursday is still being monitored.

This was all pretty well advertised.  The teleconnector modes/modalities have been been flagging this period for over a week (and going back even further considering a-priori usage of other tools), as the PNA surged and continues to do so... perhaps maxing out around +3 or even +4 standard deviations.  

Adding to the fray...the NAO has been very persistently modeled to enter a negative phase state centered on this next week. We would likely end up with an active pattern regardless of this particular teleconnector, but ..having it in place statistically backs that much more.  The combination of those two really converges on the OV/MA/NE regions for negative mid and u/a counter-balancing anomaly, ... It is no wonder that these systems are finding their greatest amplitude as they pass through these latitude/longitudes..

Also, the MJO is really powerful in phase 7 and surging even stronger (if that is possible) into Phase 8. It's hard to know what is the chicken and egg in the relationship with the PNA, but ...sufficed it is to say, the strong Phase 7-8-1-2 MJOs correlates positively with western N/A ridging, which immediately then subtends a negative counter-balance couplet down stream of eastern N/A. 

So ...long of the short, there is 7 to 10 day period of strongly integrated (S-N) Pacific that correlates to an active pattern here.

So... here we go...  A new thread to freshen points of views.

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Can't believe I'm on my way to New Orleans and missing Sunday-Monday.  Oy vey.

Heartened by WPC thinking that there is a good shot at a noreaster for Thursday.  Their headline is

EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1059 AM EST SAT FEB 11 2017

VALID 12Z TUE FEB 14 2017 - 12Z SAT FEB 18 2017

...LAST OF THE TRIFECTA OF SNOWSTORMS FOR THE NORTHEAST THURSDAY...

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10 minutes ago, JC-CT said:

Lol look at that torch coming after.

 

Mixed intellect on that actually ...

I know why/what you refer to on that... but, the hemispheric cues are mixed  - at least from the GEF's derived product suite.

It's really more of a relaxation of the +PNA  .. with some bouncing around in both the EPO and NAO.  I don't really see that as a strongly divining signal for the end of winter exactly. It just means taking the present paradigm and making it less aggressive. 

The operational runs might typically see that as a whole-scale pattern change but push comes to shove as it nears and something tamer.  If the PNA starts emerging more negative and with that death march MJO toward incoherence ... then I'd be more inclined that think we balm out the end of the month and lose out to spring early. It's not the case at the moment.

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1 minute ago, Typhoon Tip said:

 

Mixed intellect on that actually ...

I know why/what you refer to on that... but, the hemispheric cues are mixed  - at least not from the GEF's derived product suite.

It's really more of a relaxation of the +PNA  .. with some bouncing around in both the EPO and NAO.  I don't really see that as a strongly divining signal for the end of winter exactly. It just means taking the present paradigm and making it less aggressive. 

The operational runs might typically see that as a whole-scale pattern change but push comes to shove as it nears and something tamer.  If the PNA starts emerging more negative and with that death march MJO toward incoherence ... then I'd be more inclined that think we balm out the end of the month and lose to spring early.

Oh no, I don't think it ends winter. In fact, the GFS manages to backdoor us and make it an unenjoyable snow hiatus. When the PNA spikes again, boom. It's been showing up as quite a strong signal in the long range.

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I like BOS' long term discussion:


"Snow lovers rejoice, this is your week. Several signals that support
pronounced troughing over the NE CONUS through mid-February: 1) MJO
presently in phase 7 transitioning into phase 8 as H5 high pressure
over the W Pacific strengthens up against a dominant H5 low in the
vicinity of the Aleutians. Subsequently the Pacific jet is enhanced
with dominant SW-flow into the W CONUS promoting a +PNA. Work done
by others, for example, Klotzbach et al. (2016), show that in such
MJO phasing there is both the promotion of deeper troughing. lower
MSLP, more amplified storm track over the NE CONUS thus an increased
probability of snowfall events over SE New England given enhanced
moisture and greater baroclinicity per energy out of the SW and cold
air advection out of the N/NW, and a negative phase of the NAO. It`s
not entirely clear but the signals are there. Speaking of the -NAO,
2) a pseudo rex-block continues to prevail over W Europe/NE Atlantic
subsequently buckling/slowing the pattern upstream. Storm systems
less progressive to a degree, given greater residency, allowed to
mature/strengthen in closer proximity to the NE CONUS. And as to
the AO, 3) it wobbles from near-neutral to negative. Opportunities
for colder air to dislodge given polar low over N Canada and dominant
high pressure over SE Canada. However the better cross-polar flow
is still oriented more towards the E/SE Canadian maritimes.


Okay, so what does this all mean? That simply there should be no
surprise of Miller-A / Miller-B type systems emerging out of the W
to undergo rapid cyclogenesis in proximity to S New England. It is
going to be an active weather pattern over the next week so buckle
your seat belts. Shots of snow along with significant economic
and social impact. Will mainly focus on the storm for the Sunday
into Monday timeframe, only briefly touching on the storm for
Wednesday into Thursday."
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24 minutes ago, Hoth said:

Swing and a miss on the Thursday event per the GFS. Northern stream continues to outrun the ULL down south.

No argument - that's what the GFS has been doing (operational) ... Actually, hard pressed to find many members of the GEFs that don't do that...

The correlation from multiple sources supports more amplitude... It's a tricky time period.  

The ECMWF and GGEM ...those models tend to meridional bias in their middle range - despite the best intents of upgrades and so forth over the years, there is still semblance and vestige of that going on from time to time.  That "could" mean they ...Euro in this case, are too zealous with phasing like the 1978 analog stuff. 

Contrasting, the GFS used to always have a progressive bias in its middle range verification scores...

So which is it?

It seems there are countermanding argument both in support and against either in this case.  Both because of native model bias types ...but also just endemic to the pattern coming in this week.  There are multiple pros and cons evenly distributed across each guidance headache.  Christ. 

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Just now, Hoth said:

I like BOS' long term discussion:


"Snow lovers rejoice, this is your week. Several signals that support
pronounced troughing over the NE CONUS through mid-February: 1) MJO
presently in phase 7 transitioning into phase 8 as H5 high pressure
over the W Pacific strengthens up against a dominant H5 low in the
vicinity of the Aleutians. Subsequently the Pacific jet is enhanced
with dominant SW-flow into the W CONUS promoting a +PNA. Work done
by others, for example, Klotzbach et al. (2016), show that in such
MJO phasing there is both the promotion of deeper troughing. lower
MSLP, more amplified storm track over the NE CONUS thus an increased
probability of snowfall events over SE New England given enhanced
moisture and greater baroclinicity per energy out of the SW and cold
air advection out of the N/NW, and a negative phase of the NAO. It`s
not entirely clear but the signals are there. Speaking of the -NAO,
2) a pseudo rex-block continues to prevail over W Europe/NE Atlantic
subsequently buckling/slowing the pattern upstream. Storm systems
less progressive to a degree, given greater residency, allowed to
mature/strengthen in closer proximity to the NE CONUS. And as to
the AO, 3) it wobbles from near-neutral to negative. Opportunities
for colder air to dislodge given polar low over N Canada and dominant
high pressure over SE Canada. However the better cross-polar flow
is still oriented more towards the E/SE Canadian maritimes.


Okay, so what does this all mean? That simply there should be no
surprise of Miller-A / Miller-B type systems emerging out of the W
to undergo rapid cyclogenesis in proximity to S New England. It is
going to be an active weather pattern over the next week so buckle
your seat belts. Shots of snow along with significant economic
and social impact. Will mainly focus on the storm for the Sunday
into Monday timeframe, only briefly touching on the storm for
Wednesday into Thursday."

I like that too !

Very much echoes the sentiments we've been covering in here over the last week... Seems there's a pretty clear and undeniable signal afoot - let's see if we cash in off of it...

We already have for a third of it...  Monday and then Thursday don't have to happen - just that more activity is actually favored.  

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17 minutes ago, Typhoon Tip said:

I like that too !

Very much echoes the sentiments we've been covering in here over the last week... Seems there's a pretty clear and undeniable signal afoot - let's see if we cash in off of it...

We already have for a third of it...  Monday and then Thursday don't have to happen - just that more activity is actually favored.  

Yeah, given the hemispheric appeal of things, I'm definitely more optimistic than usual. Doesn't mean all the little pieces fall into place perfectly, but I'll take my chances with that look any day. That huge movement into phase 8 of the MJO is eye opening for sure.

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1 minute ago, CoastalWx said:

Looks like it's all a dream for awhile after next week.

I have no problem with that.  I want to come home from New Orleans Tuesday with 2 biggies having left 2.5 feet on the ground that the trifecta about to be completed for a 3"+ snow pack.  Enjoy that for a few days and then take it from there baby.

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