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January Forecast Discussion


REDMK6GLI

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If that happens a gradient pattern would occur, look at 2/11/94, SE ridge pumping heights, 564dm, but we still got 10+" of snow, don't get fooled by those heights rising on 500mb maps, the -EPO will keep the cold air source in Canada because the SSTs in N Pac are very warm, there will be a cutoff zone just like 94', as long as we have highpressure in Canada with an overrunning event

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Not sure if u guys can get the euro control loop on accu , but u hav to see the next 15 days.

One its cold and two there are SW every 2 days tues thrs sat then a bigger storm Monday . The OP has the tues and thrs signal

But the euro control out to day 10 matches the OP and the exact opposite of the GFS day 11 thru 15

The euro ensembles keep the alaskan ridge connected day 11 thru 15 , so the air that comes SE is arctic much like dec

And will have to fight thru the ridge .

The day 11 thru 15 bends the trough back southwest thru the Ohio valley and looks just like the JMA monthlies at 500 MB

Note the euro control run is NOT the same as the ensembles but its one of the members run 51 x so its like

An operational ensemble and I have no idea of its skill score. Hard to take anything serious outside 7 days regardless

Which side of the pond the algo was written.

So before jumping off a bridge for every winters over operational forecast theres one that says not so fast.

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Here are 6z ens hr72, if H5 comes through a hair sharper than modeled this could be a nice little event. Not sure why its being dismissed, well not all are  ;)

even though the qpf is on the lighter side 0.10 the ratios will be 20-30:1 with 850's falling from -10 to  -15 which would give us 2 or 3 inches of snow with every flake accounted for and accumulating

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even though the qpf is on the lighter side 0.10 the ratios will be 20-30:1 with 850's falling from -10 to  -15 which would give us 2 or 3 inches of snow with every flake accounted for and accumulating

 

It's been trending in the right direction, like to see how it looks by the end of today

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9z SREF is WAY amped up in comparison to the prior runs for the Tuesday storm.  Interesting.  This may continue trending further west and stronger.  It had nothing on the prior run and has everyone this run between .10 and .25, and with high ratios, this would make for a decent little snowstorm.  It has the .10+ line running from Delaware River in Northern New Jersey, through Orange County, NY, with all of extremes Southeast NY and CT at .10+, then the .25 line runs along coastal New Jersey, then cuts through Central Long Island.  It even has about .35 for eastern Long Island.  This would put NYC around .20, and there are likely to be high ratios.  It has the light snow starting around mid day on Tuesday and ending on Wednesday morning.

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The NAM will not catch Tuesdays system "if " it's bending west until its inside 48 hours. Just think back to jan 3rd

I've been saying after seeing what happened yesterday from westchester to New England you can't write any of the SW s off outside 24 hours

After this the next fight is Friday

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Next possibility is Thursday, not Friday.

 

The NAM will not catch Tuesdays system "if " it's bending west until its inside 48 hours. Just think back to jan 3rd
I've been saying after seeing what happened yesterday from westchester to New England you can't write any of the SW s off outside 24 hours

After this the next fight is Friday

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Models had shown this being a significant storm a few days ago, then backed off.  This has happened before.  Not saying it will come back enough, but it might.

 

 

How come SREF-LAG 09z has gone [03z ]from a trace of snow Tues. AM to Wed. PM to 3.5", with 4 members opting for 10"+? Comments anyone?

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Canadian would have it over by 4 am on Friday, Euro control has it over late on Thursday.  Honestly, does not make a big difference, if you want to say that the focus is Thursday afternoon and night, then fine, but anything that does happen on Thursday should be over by around midnight on Thursday.  

 

Not nitpicking Canadian dgex euro control are for fri am , regardless. After this that's the next threat


Excuse me dgex is thrs.

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12z NAM gets the very light snow up to Rt. 78 in New Jersey on this run and to NYC, the .05 line up to Trenton to Asbury Park, to eastern Long Island, and the .10 line skirts the South Jersey coast.  This is well north and west of prior runs.  It has not really moved the center of low pressure at all, it has just expanded the snow shield north and west significantly.

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The NAM will not catch Tuesdays system "if " it's bending west until its inside 48 hours. Just think back to jan 3rd

I've been saying after seeing what happened yesterday from westchester to New England you can't write any of the SW s off outside 24 hours

After this the next fight is Friday

NAM is trending NW for Tuesdays - what is encouraging is the SREF and GFS also are - 

 

http://www.tropicaltidbits.com/analysis/models/namconus/2014011912/namconus_reflectivity_us.html

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And ECMWF.  The ECMWF ensemble mean already has most of us down for around .05 on this morning's run.  And remember high ratios are likely.  

 

NAM is trending NW for Tuesdays - what is encouraging is the SREF and GFS also are - 

 

http://www.tropicaltidbits.com/analysis/models/namconus/2014011912/namconus_reflectivity_us.html

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We are just going to have to be happy with nickel and dime smaller events as

there are just too many kickers in this progressive flow for one big storm to

occur here. The other main problem once we start February is we loose the

+PNA and -AO pattern as the EPO ridge retrogrades and the PV exits 

Hudson Bay for Greenland. The JMA advertised gradient pattern will

allow the SE ridge to flex its muscles without any Atlantic blocking to

keep it in check. The -PNA/+AO pattern setting up around the beginning

of February is not a snowlovers pattern.

 

attachicon.gifpna.sprd2.gif

 

attachicon.gifao.sprd2.gif

 

 

 

There are currently two possibilities, however, concerning the medium to long term AO modality. If one were to buy into GFS based guidance, the AO relaxes and turns positive in the D7+ range. The ECMWF ensembles indicate a continued negative AO throughout the entire run. This is likely due to significant differences in the propagating of MJO wave in the tropical Pacific. GFS based guidance essentially kills the wave in phase 6, which yields a rather warm picture for the East and less blocking over the arctic. The ECMWF pushes the MJO into phase 7 as a fairly amplified wave, and this teleconnects to greater mid level ridging in the Arctic.

 

Note the following.

 

GFS based MJO forecast, phase 6:

 

2eydon6.gif

 

 

ECMWF based MJO forecast, phase 7:

 

xfudcw.gif

 

 

500mb composite for phase 6 features less blocking and higher heights in the northeast:

 

2w7jzps.gif

 

 

500mb composite for phase 7 features EPO/AO blocking and troughiness in the northeast:

 

30a3jw3.gif

 

 

So the question becomes -- which model will be superior in its depiction of tropical forcing? If the ECMWF is correct, the AO remains mostly negative, and coupled with a negative EPO, that won't be a warm picture for the Northeast, even with a -PNA and +NAO. Obviously if we lose the AO entirely, it's going to be much more difficult to maintain a normal to below normal temp pattern in the Northeast.

 

Warmer stratospheric temperatures now compared to early winter argue against the resurgence of strongly positive AO like we experienced in December. Remains to be seen what happens on that front in February, but the declining QBO would support more perturbation of the vortex.

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There are currently two possibilities, however, concerning the medium to long term AO modality. If one were to buy into GFS based guidance, the AO relaxes and turns positive in the D7+ range. The ECMWF ensembles indicate a continued negative AO throughout the entire run. This is likely due to significant differences in the propagating of MJO wave in the tropical Pacific. GFS based guidance essentially kills the wave in phase 6, which yields a rather warm picture for the East and less blocking over the arctic. The ECMWF pushes the MJO into phase 7 as a fairly amplified wave, and this teleconnects to greater mid level ridging in the Arctic.

Note the following.

GFS based MJO forecast, phase 6:

2eydon6.gif

ECMWF based MJO forecast, phase 7:

xfudcw.gif

500mb composite for phase 6 features less blocking and higher heights in the northeast:

2w7jzps.gif

500mb composite for phase 7 features EPO/AO blocking and troughiness in the northeast:

30a3jw3.gif

So the question becomes -- which model will be superior in its depiction of tropical forcing? If the ECMWF is correct, the AO remains mostly negative, and coupled with a negative EPO, that won't be a warm picture for the Northeast, even with a -PNA and +NAO. Obviously if we lose the AO entirely, it's going to be much more difficult to maintain a normal to below normal temp pattern in the Northeast.

Warmer stratospheric temperatures now compared to early winter argue against the resurgence of strongly positive AO like we experienced in December. Remains to be seen what happens on that front in February, but the declining QBO would support more perturbation of the vortex.

My experience has been 8 out of 10 times when it comes to MJO phase in medium to long range the Euro beats the GFS

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