January 24th-26th potential winter storm part 2

[Hoosier]

Just a reminder...please try to keep OT talk to a minimum and take any personal conflicts to PM. Any excessive OT talk or arguing/fighting is subject to deletion and possible warning.

Thanks

[dilly84]

Just a reminder...please try to keep OT talk to a minimum and take any personal conflicts to PM. Any excessive OT talk or arguing/fighting is subject to deletion and possible warning.

Thanks

Surprisingly enough, hasn't really been much fighting or arguing wrt this storm. Its actually a pleasant surprise.

[Stevo6899]

Looks to me like regardless if there is a northern low, the GOM low doesnt dig early enough to track along or west of the apps.

DTX: PER 00Z

EUROPEAN...INVERTED SURFACE TROUGH WILL EXTEND NORTH INTO LOWER

MICHIGAN...SUPPORTING CONTINUED CHANCE OF SNOW ON TUESDAY...WITH LOW

PRESSURE RAPIDLY DEEPENING JUST OFF THE COAST OF NEW YORK CITY ON

WEDNESDAY. WE LOOK TO BE CAUGHT IN BETWEEN THE SPLIT FLOW

WEDNESDAY-THURSDAY...WITH PERHAPS SOME LIGHT WARM ADVECTION SNOW ON

THURSDAY. IN ANY EVENT...TEMPERATURES LOOK TO BE RISING CLOSER TO

NORMAL VALUES.

DTX

[buckeye]

Looks to me like regardless if there is a northern low, the GOM low doesnt dig early enough to track along or west of the apps.

that mean ridge looks entirely too far west to support an eastcoast low or a low that develops so far southeast. very suspicious

[Stevo6899]

that mean ridge looks entirely too far west to support an eastcoast low or a low that develops so far southeast. very suspicious

The low to the north is moving things along. How a weak low is pushing a potential bigger wave east I have no idea.

[buckeye]

Surprisingly enough, hasn't really been much fighting or arguing wrt this storm. Its actually a pleasant surprise.

maybe he was referring to the earlier DT stuff....

i thought this was a big ole group hug enviornment this afternoon

[buckeye]

The low to the north is moving things along. How a weak low is pushing a potential bigger wave east I have no idea.

just read jb's update and he feels the gfs and euro are putting too much emphasis on the northern stream and 'the supposed kicker'. Said models handle this aspect very poorly. Of course he's sticking to his guns of a further west storm.

[Harry]

that mean ridge looks entirely too far west to support an eastcoast low or a low that develops so far southeast. very suspicious

This is actually a good point and something i kinda overlooked. That is a bit far to the west isnt it? Now if we can get it to build a bit more and even go a little more west..

[buckeye]

This is actually a good point and something i kinda overlooked. That is a bit far to the west isnt it? Now if we can get it to build a bit more and even go a little more west..

you might know better than me, but i believe the rule of thumb for EC lows is the mean ridge centered just east of Idaho.

[passmaster16]

I was reading the NWS State College PA discussion, and they mention about the NAM extrpolated would not bring significant snow to central PA.

EXTRAPOLATION OF THE NAM/SREF MEAN BEYOND F84 WOULD FAVOR A TRACK

TOO FAR TO THE EAST/OUT TO SEA TO BRING SIGNIFICANT SNOWS TO

CENTRAL PA.

I was understanding that the NAM had major differences with the GFS and was further west resulting in a decent hit for West/Central PA and East Ohio. Is this not the case?

[buckeye]

I was reading the NWS State College PA discussion, and they mention about the NAM extrpolated would not bring significant snow to central PA.

EXTRAPOLATION OF THE NAM/SREF MEAN BEYOND F84 WOULD FAVOR A TRACK

TOO FAR TO THE EAST/OUT TO SEA TO BRING SIGNIFICANT SNOWS TO

CENTRAL PA.

I was understanding that the NAM had major differences with the GFS and was further west resulting in a decent hit for West/Central PA and East Ohio. Is this not the case?

i kinda thought the same taking the nam verbatim. didn't seem to have anything that would lift it north. Im more enthused that it had the wet low coming out of the gulf....baby steps

[jcwxguy]

stormvista wrf shows the low on the coast

[Harry]

you might know better than me, but i believe the rule of thumb for EC lows is the mean ridge centered just east of Idaho.

Problem is the northern stuff. Boils down to hoping the GGEM ( Or whatever one it was ) is correct with dropping that northern energy back further to the west in NE. That way whatever comes up out of the south can keep heading north and is not cut off at the pass ( by stuff up north ) and shunted east.

[buckeye]

15z sref look like crap. Lots of emphasis on that kicker...way east

[buckeye]

Problem is the northern stuff. Boils down to hoping the GGEM ( Or whatever one it was ) is correct with dropping that northern energy back further to the west in NE. That way whatever comes up out of the south can keep heading north and is not cut off at the pass ( by stuff up north ) and shunted east.

any ensemble news?

[baroclinic_instability]

Ok I perused the 20 pages since last night haha, and I just want to comment since my name came up about 100 times. Real quick--when I said we needed a cutoff solution--that was 3 days ago based on that particular height field configuration. In other words--we were making judments based on what we knew of the height field at that moment. As it stands, and Stevo made a great comment earlier, the northern stream never fully detaches and cuts the low off--therefore it remains progressive even as the southern stream tries to cut off. In other words--this will likely stay east since it never fully detaches and sits there and pinwheels near the GOM. Moreover--much of the upper level energy shifts E when this system quasi-cuts off--therefore the southern wave is eventually weaker and smaller than it was suggested three days ago. Both cutting off or phasing won't do this system much good. CMC would be as good as it gets--and I have a feeling it will trend farther E with this quasi-progressive flow field.

[baroclinic_instability]

To Buckeye--the CMC cuts the precip off because of a classic stretching deformation zone. The CMC is in the process of "detaching" the northern stream from the southern stream--and in its wave is a region of stretching deformation. Quite typical in deep southern stream lows as the main belt of westerlies remains displaced well N. I drew a really crude ridge axis on the 500 hpa map with an arrow showing the northern branch westerlies. In the 700 hpa fields I drew an even more crude stretching deformation zone.

A model image of a deformation zone with an axis of dilatation (the axis the air stretches along)

[Stevo6899]

Ok I perused the 20 pages since last night haha, and I just want to comment since my name came up about 100 times. Real quick--when I said we needed a cutoff solution--that was 3 days ago based on that particular height field configuration. In other words--we were making judments based on what we knew of the height field at that moment. As it stands, and Stevo made a great comment earlier, the northern stream never fully detaches and cuts the low off--therefore it remains progressive even as the southern stream tries to cut off. In other words--this will likely stay east since it never fully detaches and sits there and pinwheels near the GOM. Moreover--much of the northern stream energy shifts E when this system quasi-cuts off--therefore the southern wave is eventually weaker and smaller than it was suggested three days ago.

When u say the low never detaches do you mean it doesnt stay west and out of the picture and if the southern low is weaker it can't deppen and come north? Wouldn't the gulf low still be strong enough to be able to push the northern stuff out of the way? We have seen this a lot this year with left over energy and vortex's. Maybe that just doesnt happen and even bigger storms can be sheared and shunted east by even the smallest details. Thanks

[Harry]

any ensemble news?

It is ugly. Have a couple that ride along just east of apps/inland but most are a coastal.

[baroclinic_instability]

Problem is the northern stuff. Boils down to hoping the GGEM ( Or whatever one it was ) is correct with dropping that northern energy back further to the west in NE. That way whatever comes up out of the south can keep heading north and is not cut off at the pass ( by stuff up north ) and shunted east.

Yeah pretty much. A few days ago we generally wanted a cutoff solution then a slowly ejecting wave with northern stream influence on the backside so it could eject N and/or NE without a negative influence of the northern stream NOw this system never cuts off to begin with and the wave-train of westerlies interferes as the southern stream low ejects NE.

[Organizing Low]

Baro

ive often heard that the northern stream is poorly handled by modeling in the mid-range......do you agree with this statement?

[Ajdos]

When u say the low never detaches do you mean it doesnt stay west and out of the picture and if the southern low is weaker it can't deppen and come north? Wouldn't the gulf low still be strong enough to be able to push the northern stuff out of the way? We have seen this a lot this year with left over energy and vortex's. Maybe that just doesnt happen and even bigger storms can be sheared and shunted east by even the smallest details. Thanks

DEC12

[baroclinic_instability]

When u say the low never detaches do you mean it doesnt stay west and out of the picture and if the southern low is weaker it can't deppen and come north? Wouldn't the gulf low still be strong enough to be able to push the northern stuff out of the way? We have seen this a lot this year with left over energy and vortex's. Maybe that just doesnt happen and even bigger storms can be sheared and shunted east by even the smallest details. Thanks

Yeah--it remains elongated and quasi-connected to the northern branch of the westerlies. This is why it takes on such a positive tilt configuration as the southern stream "lags" back while the northern stream continues eastward. In the end--this system neither digs far enough SW--and it never cuts off from the flow. What eventually occurs is a positive tilt trough with a deep southern stream PV max. Still bombs out down south--but it doesnt matter since the northern stream shunts this system eastward and develops a region of stretching deformation (see the post above to Buckeye).

[baroclinic_instability]

Baro

ive often heard that the northern stream is poorly handled by modeling in the mid-range......do you agree with this statement?

Yes and no. The general idea is there though--and both the secondary wave will come in farther eastward early on its progression and will dig less as it tracks towards the GOM--and the northern branch of westerlies will remain in partial contact with this PV max--therefore it never will cutoff. I don't know what DT is howling about--but even though the GFS solution verbatim won't pan out as it had these last 2 days--a non-detached wave with a northern stream influence will pan out. DT buys only what the Euro sells--and if it sells a monster EC snowstorm.

[Harry]

Yeah pretty much. A few days ago we generally wanted a cutoff solution then a slowly ejecting wave with northern stream influence on the backside so it could eject N and/or NE without a negative influence of the northern stream NOw this system never cuts off to begin with and the wave-train of westerlies interferes as the southern stream low ejects NE.

Pretty much.

I wonder if the cold ( keep in mind the really cold stuff shows up on satellite ) in Canada is screwing with the models making it appear that something is there that is not? Seems models struggle the most when it involves stuff coming down from Canada as it is but could the cold be adding to it? Mind you i am not as familiar as to how all that stuff is feed into modeling. As you mentioned yesterday ( i think it was? ) the models would struggle a bit with all the PAC stuff and well it has to go that route through Canada.

[Stevo6899]

Clipper coming down from canada looks impressive until it gets sheared apart by the another monster storm off the EC. Looks like the perfect storm

[baroclinic_instability]

Pretty much.

I wonder if the cold ( keep in mind the really cold stuff shows up on satellite ) in Canada is screwing with the models making it appear that something is there that is not? Seems models struggle the most when it involves stuff coming down from Canada as it is but could the cold be adding to it? Mind you i am not as familiar as to how all that stuff is feed into modeling. As you mentioned yesterday ( i think it was? ) the models would struggle a bit with all the PAC stuff and well it has to go that route through Canada.

Yeah they will have issues in an overall sense--but the Pacific wave in question is just about to crash the BC coast--and the last three days have cleared up much of the variability there. It will still help to get it sampled--but the BIG if with this wavetrain pattern in the Pacific and a strong Pacific jet is the exact timing each waves breaks off the flow--and at what amplitude and strength it eventually does. Three days ago this wave was still connected to the Pacific jet in westerly flow--in other words--it really wasn't even in formation yet. Now that it has formed and is a separate entity on its own--the models have caught on much better to what that wave will do once it comes onshore. The blob of cold air in Canada won't be an issue for the models to ingest data via satellite. I am no expert on the complex satellite techniques used--but they have some pretty complex weighting schemes and other techniques to derive satellite soundings, etc.

And this is for anyone--glance at a few of these titles and even read some of the papers here--can give an idea at the complexity involved in satellite data ingestion/assimilation. Still blwos my mind what we can do with satellites alone.

http://www.ecmwf.int...otes/LN_DA.html

[Harry]

Yeah they will have issues in an overall sense--but the Pacific wave in question is just about to crash the BC coast--and the last three days have cleared up much of the variability there. It will still help to get it sampled--but the BIG if with this wavetrain pattern in the Pacific and a strong Pacific jet is the exact timing each waves breaks off the flow--and at what amplitude and strength it eventually does. Three days ago this wave was still connected to the Pacific jet in westerly flow--in other words--it really wasn't even in formation yet. Now that it has formed and is a separate entity on its own--the models have caught on much better to what that wave will do once it comes onshore. The blob of cold air in Canada won't be an issue for the models to ingest data via satellite. I am no expert on the complex satellite techniques used--but they have some pretty complex weighting schemes and other techniques to derive satellite soundings, etc.

And this is for anyone--glance at a few of these titles and even read some of the papers here--can give an idea at the complexity involved in satellite data ingestion/assimilation. Still blwos my mind what we can do with satellites alone.

http://www.ecmwf.int...otes/LN_DA.html

Check this out.

However along comes the next disturbance and ala

So sickeningly close. ugh

[Stevo6899]

Check this out.

However along comes the next disturbance and alaSo sickeningly close. ugh

Theres always something in this helter skelter pattern we are in. Sooner or later this pattern of weak pacific NW and canadian energies dropping south will break. Are the canadian mountains causing the energies to split apart once they reach the coast? We havent seen one spread of the wealth storm come down. It's all fairly weak lows. It's about time this la nina wakes up, opens up the SW coast, the gulf and get a little se ridge going. When the gulf is open we dont need phasing to get a decent storm.

[Harry]

Theres always something in this helter skelter pattern we are in. Sooner or later this pattern of weak pacific NW and canadian energies dropping south will break. Are the canadian mountains causing the energies to split apart once they reach the coast? We havent seen one spread of the wealth storm come down. It's all fairly weak lows. It's about time this la nina wakes up, opens up the SW coast, the gulf and get a little se ridge going. When the gulf is open we dont need phasing to get a decent storm.

Good luck with getting something to cause that to happen. Really we just need to get the trough to shift west a little with more ridging in the Pacific ocean ( IN the ocean and not on the west coast )but ala that is like pulling teeth.