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March 13/14th PSU Storm

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Haven't checked lately, but can someone give me a brief run down of the ensembles for the afternoon?


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4 minutes ago, mappy said:

Haven't checked lately, but can someone give me a brief run down of the ensembles for the afternoon?


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Testing my memory, verified "1 to 1.5" qpf (slight improvements all day), similar snowfall means (8-9" dca, more north...18Z +op and ensemble suite gold).  If someone gets close to 20", it's you.

eta: and most important, thermals improved for everyone!

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Latest rundown:

Euro op: eastern outlier with good thermals but weak precip west of dc burbs. 

Euro ens: supports more expansive shield west of the op with good thermals. 

Gfs: great hit for majority of the sub and good thermals 

Gefs: supports the op with bigger precip totals S and west of dc

Cmc: 95 special but not great in western areas

Ukie: solid hit 95 and burbs but warm surface. Good temps west but lighter qpf

Jma: 18z is a crushing that everyone would be happy with 

ICON: 18z is a big hit for most everyone. 

NAM: extreme run over run consistency at ruining our disco thread. All runs have mostly been on an island and haven't added any value to the discussion whatsoever. If it supports the ops (any op which it hasn't yet) then brief discussion is warranted. Otherwise, just post all panic and dumb posts in banter thread.  

 

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4 minutes ago, mappy said:

Haven't checked lately, but can someone give me a brief run down of the ensembles for the afternoon?


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Yoda posted the GEFS in the other thread.  At the risk of jinxing my back yard, I like where Baltimore County is for this storm.  There have been few runs of any model that haven't shown a good hit.  The GEFS seems to support that.

18zGEFSEnsembleMeanhour84March11th2017.png

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LWX recently updated their probabilistic snow maps. Min/Most Likely/Max

Can see the uncertainty thinking to the east and south of DC. Likely thinking mixing/temps being an issue even with the higher QPF totals in the models. Noticed some local news media affiliates keeping totals down in those areas as well. Not that it's final but certainly a very challenging forecast. 

Looks like the max potential has gone up a bit west of 95. Most likely graphic leans closer to the max, i.e. Wetter colder solutions there, which is where the forecasters seem to be leaning. Very nice map.

 Still enough of a goal post between min and max which shows there is still a good bit of spread in the guidance.

just thought I'd put this out there with a Watch currently in effect. 

 

IMG_3099.PNG

IMG_3100.PNG

IMG_3098.PNG

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9 minutes ago, Bob Chill said:

Latest rundown:

Euro op: eastern outlier with good thermals but weak precip west of dc burbs. 

Euro ens: supports more expansive shield west of the op with good thermals. 

Gfs: great hit for majority of the sub and good thermals 

Gefs: supports the op with bigger precip totals S and west of dc

Cmc: 95 special but not great in western areas

Ukie: solid hit 95 and burbs but warm surface. Good temps west but lighter qpf

Jma: 18z is a crushing that everyone would be happy with 

ICON: 18z is a big hit for most everyone. 

NAM: extreme run over run consistency at ruining our disco thread. All runs have mostly been on an island and haven't added any value to the discussion whatsoever. If it supports the ops (any op which it hasn't yet) then brief discussion is warranted. Otherwise, just post all panic and dumb posts in banter thread.  

 

Thank you. Appreciate you taking the time to explain, even including the NAM. :lol:

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Someone asked about how this could slow down in the old thread. The problem is with no blocking (it broke down) and ridging developing in front the whole trough is somewhat progressive. The h5 low digging in and cutting off could have slowed things temporarily but it is late to the party. 

Look at where the h5 low is as the storm is slingshotting up the coast. 

IMG_0929.thumb.PNG.5c92581c05cb368de6c5e22b2796fffe.PNG

it's way back in the upper Midwest. It dives in and cuts off over us a day later.

IMG_0930.thumb.PNG.663e0c3f29eeec76f3ecdfc6d2bdcc56.PNG

But the surface system is long gone so it's cut off from any deep moisture feed. Shame because that disconnect limits things a bit. If they were phased up better and that upper low was cutting off just west of the surface low we would have a monster here. But that's pretty off the table. What I could see is some surprise snow breaking out under that upper low as it comes through. But they are way too disconnected for more then that. 

But I will take a 10"  thump snow and be very happy. All in all while it may not reach full potential as of now it's going to do pretty well. It could be a lot worse. 

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After re-reading my summary I realized 18z was pretty kind. There arent many models run at 18z but all the runs looked better than 12z. Especially the gfs/gefs and that's the most imortant of the group. 

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3 minutes ago, Bob Chill said:

After re-reading my summary I realized 18z was pretty kind. There arent many models run at 18z but all the runs looked better than 12z. Especially the gfs/gefs and that's the most imortant of the group. 

Other then a bad euro op (for some of us) today was good in general. 

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9 minutes ago, ers-wxman1 said:

LWX recently updated their probabilistic snow maps. Min/Most Likely/Max

Can see the uncertainty thinking to the east and south of DC. Likely thinking mixing/temps being an issue even with the higher QPF totals in the models. Noticed some local news media affiliates keeping totals down in those areas as well. Not that it's final but certainly a very challenging forecast. 

Looks like the max potential has gone up a bit west of 95. Most likely graphic leans closer to the max, i.e. Wetter colder solutions there, which is where the forecasters seem to be leaning. Very nice map.

 Still enough of a goal post between min and max which shows there is still a good bit of spread in the guidance.

just thought I'd put this out there with a Watch currently in effect. 

 

IMG_3099.PNG

IMG_3100.PNG

IMG_3098.PNG

 

Interesting to see the thin sliver of the 12" "Most Likely" that runs along the ridge where the Appalachian Trail runs from Front Royal to west of Leesburg up through MD into PA.  Have to guess that's because of the up-sloping with the winds out of the NE as the low spins up?  Don't see that sort of fidelity very often in the maps.  Is this a result of the updated/higher resolution models?  

 

 

 

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1 minute ago, RDM said:

 

Interesting to see the thin sliver of the 12" "Most Likely" that runs along the ridge where the Appalachian Trail runs from Front Royal to west of Leesburg up through MD into PA.  Have to guess that's because of the up-sloping with the winds out of the NE as the low spins up?  Don't see that sort of fidelity very often in the maps.  Is this a result of the updated/higher resolution models?  

 

 

 

Highlights local terrain features. That kind of detail comes mainly from forecaster input into the system for known areas of upslope enhanced snow.

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13 minutes ago, Bob Chill said:

After re-reading my summary I realized 18z was pretty kind. There arent many models run at 18z but all the runs looked better than 12z. Especially the gfs/gefs and that's the most imortant of the group. 

Yeah this setup is a kludge for us.   18z threads the needle and that's my concern.   The low needs to bomb in the right place at the right time and nothing is forcing it to.

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7 minutes ago, ers-wxman1 said:

Highlights local terrain features. That kind of detail comes mainly from forecaster input into the system for known areas of upslope enhanced snow.

Any suggestions for good sources for additional reading on this effect? I'm sitting at 800ft about a mile west of that ridge (ridge is about 1500 ft). Does the upslope only help on the east side of the ridge, or does the lift effect "carry over" some distance past the initial ridge?

I will try to keep an eye on how this pans out vs the totals a few miles on either side of the AT. 

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1 minute ago, MountainGeek said:

Any suggestions for good sources for additional reading on this effect? I'm sitting at 800ft about a mile west of that ridge (ridge is about 1500 ft). Does the upslope only help on the east side of the ridge, or does the lift effect "carry over" some distance past the initial ridge?

I will try to keep an eye on how this pans out vs the totals a few miles on either side of the AT. 

In my experience with upslope in WV it drops off pretty quick on the backside.  at 3,000 ft they have 10 fresh inches and at 1,500 ft there is almost nada. 

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2m temp 36.5 burke, va sounding on nam at 48 hours - precip looks to be knocking on the doorstep.


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The NAM is out to 48 on TT. The southern vort is a good ways south of where it was at 18Z. I dont know what that will mean down the line though.

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Rain again for 95, but closer.

 

4k NAM seems again headed for a colder solution than the 12k.

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Para nam definitely seems to come in more in line with the globals and other guidance. If that's how its going to work when it becomes operational then that's a huge improvement. 

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Just now, Bob Chill said:

Para nam definitely seems to come in more in line with the globals and other guidance. If that's how its going to work when it becomes operational then that's a huge improvement. 

Agreed, although I'd wait until seeing the panels before/after that one

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Just now, Eskimo Joe said:

NAM para is beautiful.  Looks like everyone wins.

Is there a way to see total accums?  Or is it paywalled?

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