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Central PA & the fringes - January 2015 Part II


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The northward trend better stop or we'll all be raining come Monday morning...

 

I think if this storm ends up tracking thru PA in some fashion the folks that change over would probably be worrying about sleet/zr over plain rain.. or perhaps even just the dry slot. The flat track would prevent a strong drive of warm air into the state outside of the vulnerable SW PA region and perhaps right on the PA/MD border. I don't really think there's a lot of room for this to go much further north. This system isn't going to amplify enough to drive into the cold air and established snowpack so I suspect that the surface low will run along the baroclinic boundary that should be just to the south of us. 

 

In the grand scheme of things the models aren't really that far off, but the NAM is the model that's notably to the north out of the GFS/EURO/NAM comparison, with the GFS in the middle and the Euro just a hair south and about 4mb weaker. Euro ensemble mean largely supported Euro op track and thermally (Euro seems solidly colder in PA vs the GFS/NAM). If the low went through PA I think everyone would still see solid front end snow.. but with the best forcing and precip usually north of the low, we would probably get slotted and spotty precip anyways when the low passed overhead regardless of ptype...hypothetically. I'm still pretty firm attm with thinking the track will ultimately run just under the mason-dixon though. Just my gut feeling given the setup.. hope I'm right.

 

The models could always end up dialing back slightly towards go time also... which is what just happened at the beginning of the week. 

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I think if this storm ends up tracking thru PA in some fashion the folks that change over would probably be worrying about sleet/zr over plain rain.. or perhaps even just the dry slot. The flat track would prevent a strong drive of warm air into the state outside of the vulnerable SW PA region and perhaps right on the PA/MD border. I don't really think there's a lot of room for this to go much further north. This system isn't going to amplify enough to drive into the cold air and established snowpack so I suspect that the surface low will run along the baroclinic boundary that should be just to the south of us. 

 

In the grand scheme of things the models aren't really that far off, but the NAM is the model that's notably to the north out of the GFS/EURO/NAM comparison, with the GFS in the middle and the Euro just a hair south and about 4mb weaker. Euro ensemble mean largely supported Euro op track and thermally (Euro seems solidly colder in PA vs the GFS/NAM). If the low went through PA I think everyone would still see solid front end snow.. but with the best forcing and precip usually north of the low, we would probably get slotted and spotty precip anyways when the low passed overhead regardless of ptype...hypothetically. I'm still pretty firm attm with thinking the track will ultimately run just under the mason-dixon though. Just my gut feeling given the setup.. hope I'm right.

 

The models could always end up dialing back slightly towards go time also... which is what just happened at the beginning of the week. 

Thanks mag...Hope your right.

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Take it from someone's who lived here for most of his ~23 years of life, we're far from safe...also read what red taggers are posting elsewhere.

 

The 18z GFS wasn't even remotely close to us mixing tho.... It is better for us for a GFS-like scenario to verify because we get the better dynamics. We don't need Philly to be all snow for us to get a good snow storm... I'm not worried, especially since the south tick recorrection is historically bound to happen anyway within the next 48 hours

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The 18z GFS wasn't even remotely close to us mixing tho.... It is better for us for a GFS-like scenario to verify because we get the better dynamics. We don't need Philly to be all snow for us to get a good snow storm... I'm not worried, especially since the south tick recorrection is historically bound to happen anyway within the next 48 hours

CTP mentions this in their afternoon discussion. A good read for anyone who hasn't read it.

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I think if this storm ends up tracking thru PA in some fashion the folks that change over would probably be worrying about sleet/zr over plain rain.. or perhaps even just the dry slot. The flat track would prevent a strong drive of warm air into the state outside of the vulnerable SW PA region and perhaps right on the PA/MD border. I don't really think there's a lot of room for this to go much further north. This system isn't going to amplify enough to drive into the cold air and established snowpack so I suspect that the surface low will run along the baroclinic boundary that should be just to the south of us. 

 

In the grand scheme of things the models aren't really that far off, but the NAM is the model that's notably to the north out of the GFS/EURO/NAM comparison, with the GFS in the middle and the Euro just a hair south and about 4mb weaker. Euro ensemble mean largely supported Euro op track and thermally (Euro seems solidly colder in PA vs the GFS/NAM). If the low went through PA I think everyone would still see solid front end snow.. but with the best forcing and precip usually north of the low, we would probably get slotted and spotty precip anyways when the low passed overhead regardless of ptype...hypothetically. I'm still pretty firm attm with thinking the track will ultimately run just under the mason-dixon though. Just my gut feeling given the setup.. hope I'm right.

 

The models could always end up dialing back slightly towards go time also... which is what just happened at the beginning of the week.

thanks Mag
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Starting to get into the range for the RGEM to start having a take on this storm as well. Here's the edge of the RGEM range at 54h vs NAM 54h. Note that RGEM is solidly south of the NAM. (and the 18z GFS has it's low placed pretty much where the NAM has it at that particular hour and same strength)

 

RGEM

post-1507-0-66445900-1422661996_thumb.gi

 

NAM

post-1507-0-76896000-1422662017_thumb.gi

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It seems like once we see a consistent north trend develop, it never really abates.  It’s not like models are jumping around, they are just ticking north with each suite.  Hopefully I’m wrong but I think the southern crew might be disappointed with this one.  Hopefully you true central people can cash in.

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Even up here I'm slightly uncomfortable about the north trend. I'd take the 12z Euro/gfs and run if I could.

Watch out for the 850mb low track closely. We've seen too many times a nice thermal profile modeled at this stage even when on or south of the 850mb low, and every time the warm air at 750-800mb was undermodeled and it turned into a pellet-fest, if not freezing rain. 

 

The 18z NAM has the 850 low making it up to almost the NY/PA border, and the GFS has it roughly on I-80. The 12z GGEM and GFS have it along maybe Rt. 22. From there south, I think sleet and freezing rain can be a significant part of the storm, and if the 18z models are right, anywhere I-80 and south.

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It seems like once we see a consistent north trend develop, it never really abates.  It’s not like models are jumping around, they are just ticking north with each suite.  Hopefully I’m wrong but I think the southern crew might be disappointed with this one.  Hopefully you true central people can cash in.

every model has given us a good bit of snow to start I am not sure why the hopeless comments. It will be nice when we see good 0z runs

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Watch out for the 850mb low track closely. We've seen too many times a nice thermal profile modeled at this stage even when on or south of the 850mb low, and every time the warm air at 750-800mb was undermodeled and it turned into a pellet-fest, if not freezing rain. 

 

The 18z NAM has the 850 low making it up to almost the NY/PA border, and the GFS has it roughly on I-80. The 12z GGEM and GFS have it along maybe Rt. 22. From there south, I think sleet and freezing rain can be a significant part of the storm, and if the 18z models are right, anywhere I-80 and south.

Thank you for the heads up.

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NAM held it ground since 12z today implies mixing in LSV and north potentially let's see what the other models trend towards they were all favorable for a PA snowstorm

 

Looking at the 850 map, even my location goes above freezing at hr60. South and east of I-80 and I-81 mix/change on this run.

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Station: 40.80,-75.96

Latitude: 40.80

Longitude: -75.96

-------------------------------------------------------------------------------

LEV PRES HGHT TEMP DEWP RH DD WETB DIR SPD THETA THE-V THE-W THE-E W

mb m C C % C C deg knt K K K K g/kg

-------------------------------------------------------------------------------

0 1000 -1

SFC 958 341 -0.3 -0.9 96 0.5 -0.6 87 6 276.2 276.8 274.8 286.4 3.74

2 950 408 -1.1 -1.5 97 0.4 -1.3 89 9 276.0 276.6 274.5 285.9 3.60

3 900 839 -1.0 -1.2 98 0.2 -1.1 185 16 280.5 281.1 277.3 291.3 3.88

4 850 1297 1.0 0.8 98 0.3 0.9 233 36 287.2 288.0 281.7 300.7 4.76

5 800 1783 -1.4 -1.6 98 0.3 -1.4 245 32 289.7 290.5 282.2 302.0 4.25

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Can't we have ONE FREAKING STORM where we don't have to worry about fringing, mix lines, or any of that bullshyte?

I was thinking the same thing...when those maps from earlier today were showing a statewide plastering, I thought to myself "this is too good to be true."

 

And, unfortunately...it looks like it was. 

 

You know, there's a reason why big, double digit snows are a once in a decade event down this way. We, and I'm not including you because I know how painful it was up that way in previous years, but down here (and especially in NYC) were utterly spoiled. 

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