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Storm threat (Early Jan) 1/4 - 1/6


SACRUS

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The euro at 132 seems too look a little more organized off to our south and east than in recent days , then after running light precip through our area it weakens it . Sunday is 5 days out , maybe in the next day or 2 we can get this a bit tighter , Cause after its sleepy time for 2 to 3 weeks .

The threat around 144 is our best shot, it comes at a relatively classic time too overall as the pattern is flipping from cold to warm.

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The threat around 144 is our best shot, it comes at a relatively classic time too overall as the pattern is flipping from cold to warm.

Yeh , usually we get good snows on the back end of " cold " patterns .I agree it would be nice if the trof is going to be lifting out of the east , why not send it on its way with a bang .

I go back to so many good storms , they like to occur on the weekends and then the snow cover gets wiped out within a week as the pattern changed .

My feeling is its such a bad pattern we may just gona close this period out frustrated .

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The 12z GFS has an attention getting trof at days 4-5.  The height field to our north would keep any coastal low well to the southeast (as modeled) but it's definitely something to watch. The GGEM and Euro and ensembles generally agree with the SW cutoff moving east and interacting with a s/w dropping south from Canada to carve out an eastern trof by Sunday or Monday.  Right now the ensembles are not too encouraging, but I will be curous to see if they offer anything more enticing today or tonight.

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The 12z GFS has an attention getting trof at days 4-5.  The height field to our north would keep any coastal low well to the southeast (as modeled) but it's definitely something to watch. The GGEM and Euro and ensembles generally agree with the SW cutoff moving east and interacting with a s/w dropping south from Canada to carve out an eastern trof by Sunday or Monday.  Right now the ensembles are not too encouraging, but I will be curous to see if they offer anything more enticing today or tonight.

 

Today's 12z GGEM brings snow to the area for this above threat.

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Earth, what do you mean by the "pacific pattern" and how are you quantifying "so fast?"

 

It takes around 48hours for the ridge axis to move from the west coast to roughly Minnesota.  That seems pretty slow to me and the flow is amplified out there.  I think there is enough room for the trof to dig and pump heights on the east coast.  But I also doubt it will happen.

 

I think a stronger surface low into the deep south around 84hrs would help create a positive feedback on the whole development process and allow more digging and strengthening of the trof.  The modeled temp and height fields in the US don't look favorable for a strong low in the south and up in Canada they don't look fovorable for the development of a less progressive trof (the flow is very flat from the upper lakes through towards the N. Atlantic).  Until other guidance shows a better outcome, I feel like we have a low chance threat.

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I'd like to see more south or southwesterly mid and upper level flow in New England and the Maritimes in advance of the trof.  The speed of the propagation of the trof looks pretty typical to me.  I just don't love the height field yet.

 

It looks like the GGEM delivers a little light precip with the old SW cutoff and has a much weaker trailing Canadian shortwave.  The GFS is more aggressive in dampening out the initial cutoff and amplifies the trailing wave more significantly.  I prefer the GFS method and would like to see better s/w interaction and even more southerly digging and sharpening.

The 12z GGEM comes close to a big phase but the flow is just too fast
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Earth, what do you mean by the "pacific pattern" and how are you quantifying "so fast?"

 

It takes around 48hours for the ridge axis to move from the west coast to roughly Minnesota.  That seems pretty slow to me and the flow is amplified out there.  I think there is enough room for the trof to dig and pump heights on the east coast.  But I also doubt it will happen.

 

I think a stronger surface low into the deep south around 84hrs would help create a positive feedback on the whole development process and allow more digging and strengthening of the trof.  The modeled temp and height fields in the US don't look favorable for a strong low in the south and up in Canada they don't look fovorable for the development of a less progressive trof (the flow is very flat from the upper lakes through towards the N. Atlantic).  Until other guidance shows a better outcome, I feel like we have a low chance threat.

 

Well beginning at around 96-102 hours on the 12z GFS you can see the ridge (with the axis centered near the 4 corners) is at least decently amplified and in a fair spot (if you want East Coast amplification). But 6-12 hours after that it moves east and de-amplifies fairly rapidly, and we also have a kicker of sorts coming across the international border by 108-114 hours as well. In the end the shortwave never truly amplifies and actually gets "squished" by the fast pacific flow if you look at the vorticity at 120 hrs.

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The 12z GFS op run is probably the most threatening of all its ensemble members, and even that solution is pretty far from a snow threat.  The Euro dampens the cutoff and then squashes the trailing wave behind it harmlessly in the south.  You really have to squint to find a snow threat. 

 

At least the synoptic evolution and developing trof axis give us some minor chance in the midrange, but with guidance really consitent through day 3, it's barely worth a look.

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 H5 pattern doesn't look half bad for later this week. We have the PNA spike and consequently a northern vort slides down the flow into the Plains while another shortwave is being ejected NE within the split flow.

The synoptics around 70hrs don't look terrible, and one would think we're leading up to a potential phase given the appearance here:

3517gwy.png


But that rapidly falls apart as the southern vort shoots out ahead of the northern short wave, suppressing Eastern heights and ultimately resulting in a non event.

rhqtlt.png


However, H5 has been trending a bit better for this time frame, and it would not take much errors in s/w timing from this range to produce something minor         

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 H5 pattern doesn't look half bad for later this week. We have the PNA spike and consequently a northern vort slides down the flow into the Plains while another shortwave is being ejected NE within the split flow.

The synoptics around 70hrs don't look terrible, and one would think we're leading up to a potential phase given the appearance here:

But that rapidly falls apart as the southern vort shoots out ahead of the northern short wave, suppressing Eastern heights and ultimately resulting in a non event.

However, H5 has been trending a bit better for this time frame, and it would not take much errors in s/w timing from this range to produce something minor         

 

I agree with this overall assessment.  The problem is the 12z op is the most favorable of any guidance right now.  It is an outlier with the handling of the northern stream s/w and even so it comes up short.

 

The sw ejecting northeast is moving into an area of ridging so it will almost certainly weaken.  I think we have to hang our hopes on the northern stream vort carving out a much stronger, sharper trof (possible since the incipient energy is somewhere in the north Pacific.  I think the best case is the southern stream improves the baroclinicity in the southeast US before dampening (WAA out ahead) and the trailing wave with its associated PVA feeds off of that baroclinic environment, forming a SLP in the southeast and helping to tilt the developing trof negative.  But right now I think the GGEM with its stronger southern wave is most reasonable.

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Actually the end of the 12z EURO is not THAT bad. If the high pressure over SE Canada can trend stronger (currently progged to be 1020mb) then the the cutter might be forced to redevelop offshore and become a coastal threat. Perhaps that would push the heights far enough offshore that they would help us instead of hurt us. Not sure what good that would do though as there is no real cold air to speak of in the Eastern third of the country during this time frame. 10+ 850 line is in central New England. Have to believe this is overdone but taken verbatim this would be 60 degree temps. This is all mainly wishcasting though. Amazingly the GFS and the Euro are in good agreement.

 

 

gfs_namer_192_850_temp_ht.gif

f192.gif

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NAM looks good through 72 hours and then has this weird negative interference between the two shortwaves. We've seen this two or three times already this winter, maybe it has something to do with the flat upper level flow ahead of the southernmost shortwave...not sure. You would think there would be more moisture involved, too, since the first/southern shortwave digs pretty far south near the gulf. But the interference and non-phase from the northern stream shortwave is curious and its something we've seen multiple times this year already.

 

f78.gif

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The 12z Euro actually produced a dusting of snow on Sunday morning from Trenton to Toms River and North. It spits out a whopping .02 to .04 throughout Northern New Jersey, with areas along the Delaware River showing up as a half inch on the snowfall output map. Well, that is all we have to talk about right now. It is just of note because it does not show up on the StormVista maps because their cutoff is at .05.

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Where was it in January 2012 ?

 

Well looks like the cool after at hr 240 that was on most of the 12z guidance went away or has been pushed back on most of the 00z guidance. Hard to remember the last time I saw the 10+ 850 line into SE Canada in mid January

 

f240.gif

where was it in January 2012 ?

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