Dec 11-13 MW/Lakes/OV Snow Event?

[buckeye]

word on the street is the Korean has this as a coastal.

lol

[Chicago Storm]

word on the street is the Korean has this as a coastal.

lol

Keep this crap out of my topic.

[Moneyman]

yeah, he didn't say how far SE. He said something along the lines of them being like last nights 00z Euro Ensembles, right?

Yeah. They come out in like 20-30 mins. The Euro ens. means that is.

[buckeye]

Keep this crap out of my topic.

my bad....i'll hold off on posting the coamps

[weatherbo]

run from 12z gfs, so if gfs is out to lunch on placment, wrf likely is too.

FWIW though:

[daddylonglegs]

It should come as no shock when this thing drops a foot+ on most of Wisconsin...bank it

[Hoosier]

Aleking - perhaps a short period of lake enhancement if track is favorable? Thermodynamics look marginal though for the time you'd have a favorable wind direction. The low level flow is ripping so I wouldn't look for anything really organized probably until the winds shift it out of your area.

[JoMo]

Euro, UK, GFS, GGEM, NOGAPS...... And the Euro and UK are not on the same page...

[Chicago WX]

run from 12z gfs, so if gfs is out to lunch on placment, wrf likely is too.

FWIW though:

GFS is probably wrong, but thanks for posting that map. I'd love to see it happen.

[A-L-E-K]

Aleking - perhaps a short period of lake enhancement if track is favorable? Thermodynamics look marginal though for the time you'd have a favorable wind direction. The low level flow is ripping so I wouldn't look for anything really organized probably until the winds shift it out of your area.

Bo's map would imply as much, but we're pretty far out to get a good idea. We do best enhancement wise when we get a a favorable wind direction to coincide with a trowal feature and that appears to be a possibility and when it happens can easily drop 4-6 inches pretty quick. The 12z runs give the impression i'll be hurt by the lake early with the warm punch and east/south east winds and then helped by the lake on the flip side with the edge of the defo band.

[weatherbo]

GFS is probably wrong, but thanks for posting that map. I'd love to see it happen.

yeah looks good on paper anyway and fun to look at...

[beavis1729]

From Gil Sebenste at NIU:

Saturday and Sunday...well, the Polar and subtropical jet streams will

phase and produce a big low pressure system as they do. But when and where

this exactly happens is the big unknown, and that directly affects the

track of the low, and its intensity while it affects us. There's little

doubt it will be a major system...not the monster we saw a month ago, but

very intense nonetheless. And it will drop down Arctic air into our area

for the first time early next week. That we know. What we don't know is

the track, how much we'll get, and in what form. The GFS is out to lunch,

because we see it phasing the jet streams at the wrong time and sending

the low down into Tennessee. It's wrong, and climatologically it's way

far south. Then there's the European model, which tracks it right over

DeKalb and I-88 into Chicago on Saturday. That brings us first maybe a

little snow, then freezing rain, then rain, then snow with a flash freeze

on Saturday. Who to believe? Neither, right now. This thing is out in the

Pacific, in a low data area. Methinks the European is somewhat too far

north, and the GFS model is way too far south, while the Canadian

Canadian model taking it through central Illinois might be the best call,

and climatologically, it's close. But again, until Thursday, this thing

is in no-man's land, but be prepared for something ugly, spelled U-G-L-Y

this weekend. Sunday should just be awful, with very cold air moving in

on 40 MPH wind gusts, the GFS and European say it could go as high as 50

MPH in gusts. Blowing and drifting snow...nasty. Sunday, plan on spending

it at home or only with local travel...and if it isn't as nasty, count

your blessings. Look for highs in the lower and maybe middle 30s on

Saturday, and then free-falling on Sunday into the single digits with 40

MPH wind gusts from the north. Lake effect snow in the Chicago area into

northwest Indiana could really be big with this one, if you have travel

plans around the Great Lakes this weekend.

[Hoosier]

Bo's map would imply as much, but we're pretty far out to get a good idea. We do best enhancement wise when we get a a favorable wind direction to coincide with a trowal feature and that appears to be a possibility and when it happens can easily drop 4-6 inches pretty quick. The 12z runs give the impression i'll be hurt by the lake early with the warm punch and east/south east winds and then helped by the lake on the flip side with the edge of the defo band.

Yeah, I saw that map right after I posted. I think mid lake temps are still in the mid 40's but I'm not sure.

[OceanStWx]

Wow, the GFS has some absolutely absurd low level winds on the back side...check out the 70-75 kt. max at 900 mb from about STL southward into Arkansas at 120 hours. Good thing it seems to have an inversion at that time.

I can believe it, considering the jet dynamics and cold air mass involved diving down behind it, there should be a very nice trop fold in that dry slot.

[A-L-E-K]

From Gil Sebenste at NIU:

Gil sounds like he has the right idea with riding something between the Euro and GFS. The incredible cold air ripping down the backside is going to be something. This might be a legit heavy rain to heavy snow event, i know we all love those.

[Chicago WX]

Hot off the presses...12z Euro ensemble mean.

[A-L-E-K]

Hot off the presses...12z Euro ensemble mean.

Very similar to hte Canadian OP (http://www.meteo.psu.edu/~gadomski/CMC_12z/f126.gif) and looking pretty good for snow.

[TheWeatherPimp]

Its hard not to think that with such a potent early season Arctic airmass, that the models may be underdoing/retreating the cold/shallow cold airmass a bit?

[Jim Martin]

That is looking good for northwest Ohio for accumulating snow.

[TheWeatherPimp]

LOL at IND's AFD:

LONG TERM /FRIDAY THROUGH TUESDAY/

DID NOT DEVIATE SIGNIFICANTLY FROM HPC GUIDANCE...AS ENORMOUS

SPREAD AND MODEL INCONSISTENCY IN THE EXTENDED LEADS TO A LOW

CONFIDENCE FORECAST. POTENTIAL EXISTS FOR ACCUMULATING

SNOWFALL...OR MOSTLY RAIN. POINT OF GENERAL AGREEMENT IS A RETURN

TO MUCH COLDER TEMPS EARLY NEXT WEEK. STRONG SURFACE PRESSURE

GRADIENT MAY RESULT IN QUITE WINDY CONDITIONS TO GO ALONG WITH THE

COLD TEMPS SUNDAY AND MONDAY.

[Chicago WX]

Its hard not to think that with such a potent early season Arctic airmass, that the models may be underdoing/retreating the cold/shallow cold airmass a bit?

Only problem with that I believe is the preceding clipper, which tracks along or just north of the border, scours out all the arctic air.

[OceanStWx]

I unfortunately don't have full access to the Euro at home, so I am unsure how it handled these features for the 12z run, but we were discussing at the office the reason for the wide ranging solutions. As most people have suspected it's because the models aren't handling the surface and upper air feature (relative to one another) correctly. I can use the GFS as an example to hopefully explain.

For starters the strongest part of the jet is still entering the trough, suggesting further digging. Also, for the developing jet streak exiting the trough the greatest diffluence over the lower Ohio Valley. This would suggest the "greatest" moisture and triple point not being NW of the KY/IN/IL border region.

The result is an occlusion in the Ohio Valley, where you would expect it relative to the upper air features. The problem with the Euro was that it had a similar upper air set up but a surface low (and resulting QPF) well NW of the developing jet streak. Based on what we know about jet circulations, etc, this would be difficult to accomplish. For this reason I'm expecting an eventual correction south, just how far is the question.

[A-L-E-K]

Its hard not to think that with such a potent early season Arctic airmass, that the models may be underdoing/retreating the cold/shallow cold airmass a bit?

The real potent artic air comes in on the backside. The cold airmass we're seeing now will start getting pushed out well ahead, SREFs have been showing this pretty well. It's possible the erosion of the surface cold over the area (especially those with snow pack) is being slightly overdone (hence mention of freezing drizzle in this area with the clipper). In the end the phase timing and other larger issues are going to dictate the track more than a shallow cold airmass.

[patrick7032]

Very similar to hte Canadian OP (http://www.meteo.psu...MC_12z/f126.gif) and looking pretty good for snow.

It will be interesting to see how the models react when the mid and upper level energy enter the RAOB network on Friday. I don't know about others....but last year and this year to me beyond a f108 range it seems the EURO and CMC are closer to track verification compared to the GFS....I usually lean towards the CMC.

[Chicago WX]

I unfortunately don't have full access to the Euro at home, so I am unsure how it handled these features for the 12z run, but we were discussing at the office the reason for the wide ranging solutions. As most people have suspected it's because the models aren't handling the surface and upper air feature (relative to one another) correctly. I can use the GFS as an example to hopefully explain.

For starters the strongest part of the jet is still entering the trough, suggesting further digging. Also, for the developing jet streak exiting the trough the greatest diffluence over the lower Ohio Valley. This would suggest the "greatest" moisture and triple point not being NW of the KY/IN/IL border region.

The result is an occlusion in the Ohio Valley, where you would expect it relative to the upper air features. The problem with the Euro was that it had a similar upper air set up but a surface low (and resulting QPF) well NW of the developing jet streak. Based on what we know about jet circulations, etc, this would be difficult to accomplish. For this reason I'm expecting an eventual correction south, just how far is the question.

Thanks for the informative post.

[A-L-E-K]

I unfortunately don't have full access to the Euro at home, so I am unsure how it handled these features for the 12z run, but we were discussing at the office the reason for the wide ranging solutions. As most people have suspected it's because the models aren't handling the surface and upper air feature (relative to one another) correctly. I can use the GFS as an example to hopefully explain.

For starters the strongest part of the jet is still entering the trough, suggesting further digging. Also, for the developing jet streak exiting the trough the greatest diffluence over the lower Ohio Valley. This would suggest the "greatest" moisture and triple point not being NW of the KY/IN/IL border region.

The result is an occlusion in the Ohio Valley, where you would expect it relative to the upper air features. The problem with the Euro was that it had a similar upper air set up but a surface low (and resulting QPF) well NW of the developing jet streak. Based on what we know about jet circulations, etc, this would be difficult to accomplish. For this reason I'm expecting an eventual correction south, just how far is the question.

Does a track from So. Ill to Detroit work for you. (unscrupulous rhetorical weenie post)

[OceanStWx]

Thanks for the informative post.

My pleasure. In fact doing a little dprog/dt of the last 4 GFS runs, the 12z run was a significant shift NW of jet structure. Especially from the 06z.

[Hoosier]

LOL at IND's AFD:

LONG TERM /FRIDAY THROUGH TUESDAY/

DID NOT DEVIATE SIGNIFICANTLY FROM HPC GUIDANCE...AS ENORMOUS

SPREAD AND MODEL INCONSISTENCY IN THE EXTENDED LEADS TO A LOW

CONFIDENCE FORECAST. POTENTIAL EXISTS FOR ACCUMULATING

SNOWFALL...OR MOSTLY RAIN. POINT OF GENERAL AGREEMENT IS A RETURN

TO MUCH COLDER TEMPS EARLY NEXT WEEK. STRONG SURFACE PRESSURE

GRADIENT MAY RESULT IN QUITE WINDY CONDITIONS TO GO ALONG WITH THE

COLD TEMPS SUNDAY AND MONDAY.

Pretty much true though.

[patrick7032]

I unfortunately don't have full access to the Euro at home, so I am unsure how it handled these features for the 12z run, but we were discussing at the office the reason for the wide ranging solutions. As most people have suspected it's because the models aren't handling the surface and upper air feature (relative to one another) correctly. I can use the GFS as an example to hopefully explain.

For starters the strongest part of the jet is still entering the trough, suggesting further digging. Also, for the developing jet streak exiting the trough the greatest diffluence over the lower Ohio Valley. This would suggest the "greatest" moisture and triple point not being NW of the KY/IN/IL border region.

The result is an occlusion in the Ohio Valley, where you would expect it relative to the upper air features. The problem with the Euro was that it had a similar upper air set up but a surface low (and resulting QPF) well NW of the developing jet streak. Based on what we know about jet circulations, etc, this would be difficult to accomplish. For this reason I'm expecting an eventual correction south, just how far is the question.

GREAT INPUT....I agree with you and my "first guess" would be a track from KPAH to KOSU....based on the upper dynamics....what do you think?

[buckeye]

I unfortunately don't have full access to the Euro at home, so I am unsure how it handled these features for the 12z run, but we were discussing at the office the reason for the wide ranging solutions. As most people have suspected it's because the models aren't handling the surface and upper air feature (relative to one another) correctly. I can use the GFS as an example to hopefully explain.

For starters the strongest part of the jet is still entering the trough, suggesting further digging. Also, for the developing jet streak exiting the trough the greatest diffluence over the lower Ohio Valley. This would suggest the "greatest" moisture and triple point not being NW of the KY/IN/IL border region.

The result is an occlusion in the Ohio Valley, where you would expect it relative to the upper air features. The problem with the Euro was that it had a similar upper air set up but a surface low (and resulting QPF) well NW of the developing jet streak. Based on what we know about jet circulations, etc, this would be difficult to accomplish. For this reason I'm expecting an eventual correction south, just how far is the question.

cool stuff....hope your expectations come to fruition.