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End of February/ Early March Discussion Thread 2015


Allsnow

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probably climate change

http://iopscience.iop.org/1748-9326/10/1/014005

New metrics and evidence are presented that support a linkage between rapid Arctic warming, relative to Northern hemisphere mid-latitudes, and more frequent high-amplitude (wavy) jet-stream configurations that favor persistent weather patterns. We find robust relationships among seasonal and regional patterns of weaker poleward thickness gradients, weaker zonal upper-level winds, and a more meridional flow direction. These results suggest that as the Arctic continues to warm faster than elsewhere in response to rising greenhouse-gas concentrations, the frequency of extreme weather events caused by persistent jet-stream patterns will increase.

 

There was also a recent  paper just focusing on the record blocking pattern in the Pacific.

 

http://onlinelibrary.wiley.com/doi/10.1002/2014GL059748/abstract

 

 

Abstract

The 2013–2014 California drought was initiated by an anomalous high-amplitude ridge system. The anomalous ridge was investigated using reanalysis data and the Community Earth System Model (CESM). It was found that the ridge emerged from continual sources of Rossby wave energy in the western North Pacific starting in late summer and subsequently intensified into winter. The ridge generated a surge of wave energy downwind and deepened further the trough over the northeast U.S., forming a dipole. The dipole and associated circulation pattern is not linked directly with either El Niño–Southern Oscillation (ENSO) or Pacific Decadal Oscillation; instead, it is correlated with a type of ENSO precursor. The connection between the dipole and ENSO precursor has become stronger since the 1970s, and this is attributed to increased greenhouse gas loading as simulated by the CESM. Therefore, there is a traceable anthropogenic warming footprint in the enormous intensity of the anomalous ridge during winter 2013–2014 and the associated drought.

 

 

February 16, 2015 

 

The Ridiculously Resilient Ridge Returns; typical winter conditions still nowhere to be found in California

 

 

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The fall SST on the JMA keeps the same profile. Man it would be incredible if we pull that off for a 3rd straight year.

 

Yeah, that would be amazing if it turns out to be  correct. The latest Euro weeklies keep the record -EPO ridge

in place for at least another 4 weeks.

 

 

https://fox12weather.wordpress.com/2015/02/23/cooler-weather-ahead-but-not-much-rain-or-mountain-snow/

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Yawn, I think you're one of the few posters left still rooting for cold and snow. Spring is on the way. Most of the 5" thst fell here on Saturday is gone and bare spots are starting to show up along the highways.

 

thats a cop out man..., we get winter for 4 months out of the year. March can have some of the best storms of the year. Its going to get warm and stay that way for a while, we can at least continue to be weenies

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thats a cop out man..., we get winter for 4 months out of the year. March can have some of the best storms of the year. Its going to get warm and stay that way for a while, we can at least continue to be weenies

Exactly, by mid June I'll already check out historic blizzards on Wikipedia, I think we should all enjoy whatever winter we have left.
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The SREFs can be a useful tool, if you understand their biases.  In general, only the SREF NMM members are worth much.   The ARW and NMB members have a pronounced NW/wet bias with coastal storms.

 

Averaging the NMM members from the past 2 SREF runs gives a mean of about 0.05" QPF at LGA, 0.1" at ISP and 0.2" on the Twin Forks.  

 

Ratios should be around 20:1.  This site has a good objective snow ratio forecast based on NAM and GFS:

http://www.meteor.iastate.edu/~ckarsten/cobb/cobb.php?model=namm

 

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I know people are focused on the first system for Thursday and rightly so but I think the system for next Tuesday has the best chance of delivering a widespread significant winter weather event. 

 

The 00z Euro delivered another pretty nasty ice storm, but at day 7-8 this will change 1000 times over.

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I know people are focused on the first system for Thursday and rightly so but I think the system for next Tuesday has the best chance of delivering a widespread significant winter weather event. 

 

The 00z Euro delivered another pretty nasty ice storm, but at day 7-8 this will change 1000 times over.

0z GGEM was similiar but slightly colder. I agree about the storm for next week.

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Look at H5 around 36 hours on all guidance.  This is the kind of sneaky storm that comes a bit further north on occasion.  That is a southern stream wave... not the northern stream polar stuff we've been dealing with.  I wouldn't completely dismiss the SREF outliers in this case... whereas for most of the year I have ignored them.  The southern wave is on the downstream side of the LW trof.  You always gotta watch that for more amplification than modeled.  I would be cautiously, yet hopefully excited if I were in SNJ.  But I think this has a little room to ride up even further.  Low likelyhood however.

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