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Lake Effect Snow Belts Discussion Thread


TugHillMatt

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Too early to go too deep into details for the weekend, but some general consistency emerging in the models as far as the evolution of the expected LES band off of southern Lake Michigan.  What starts out as a setup favoring the eastern side of the lake should transition toward one that favors NW IN and eventually may try to work toward the IL/WI shore as steering layer winds take on some easterly component.  Thermodynamics slowly degrade on Sunday, but delta Ts and inversion heights look pretty good for much of the day and I suspect we may see a robust band for much of the day.

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Too early to go too deep into details for the weekend, but some general consistency emerging in the models as far as the evolution of the expected LES band off of southern Lake Michigan. What starts out as a setup favoring the eastern side of the lake should transition toward one that favors NW IN and eventually may try to work toward the IL/WI shore as steering layer winds take on some easterly component. Thermodynamics slowly degrade on Sunday, but delta Ts and inversion heights look pretty good for much of the day and I suspect we may see a robust band for much of the day.

Several model cycles in a row on the globals have even portrayed a mesolow over southern Lake Michigan on Sunday. Pretty impressive that lower resolution guidance is in good agreement on that, and it argues for maintenance of the band, and as you mentioned the steering layer winds becoming more easterly as it is. Do you recall what soundings were indicating for inversion heights for the Jan 20-21 2014 event as compared to what models are showing this weekend?

Since I'm off this weekend, if there's a powerhouse band close enough to here well into Sunday, I may try to chase it.

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Several model cycles in a row on the globals have even portrayed a mesolow over southern Lake Michigan on Sunday. Pretty impressive that lower resolution guidance is in good agreement on that, and it argues for maintenance of the band, and as you mentioned the steering layer winds becoming more easterly as it is. Do you recall what soundings were indicating for inversion heights for the Jan 20-21 2014 event as compared to what models are showing this weekend?

Since I'm off this weekend, if there's a powerhouse band close enough to here well into Sunday, I may try to chase it.

 

 

I want to say at least 10,000 feet for the Jan 2014 event.

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Tonight into tomorrow looks to be one of those special times where we cash in on LES on this way. This occurs down here 2-3 times a year when trajectories and flow are just right. Hoping to see 2-3" when all is said and done.

Good luck to you on this one.  IND is thinking possibly up to an inch for me way down here ne of Indpls.  Really hoping to see my cousin get a huge lake effect in Highland IN later this weekend.

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The 12z GFS shifted back east a lot for the weekend event.  We finally get the band on us after 12z Sun but it's weakening a lot by that point.

 

Let's see what the rest of the suite does.  Still open to getting a motel in MGC or PPO.

 

 

Euro seems more favorable for Valpo.

 

It'll be nice when this gets into hi-res range.

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Euro seems more favorable for Valpo.

 

It'll be nice when this gets into hi-res range.

 

Yeah it does.  Going off just the surface wind field, the axis of convergence/mesolow sits on us for about 6-9 hours Saturday night-Sunday morning.

 

Our LES-loving prof here is actually feeling bearish about the weekend, so that has me concerned.  Not to mention I still have PTSD from Jan 2014, and telling clients we forecasted for to expect 6-12" and ending up with 0.2".

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Yeah it does.  Going off just the surface wind field, the axis of convergence/mesolow sits on us for about 6-9 hours Saturday night-Sunday morning.

 

Our LES-loving prof here is actually feeling bearish about the weekend, so that has me concerned.  Not to mention I still have PTSD from Jan 2014, and telling clients we forecasted for to expect 6-12" and ending up with 0.2".

 

 

What's his concern?  Location?  Flake size?

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Could rip pretty good for a while in Valpo tomorrow. LOT calling for up to 6" in northeast Porter.

In my AFD, mentioned our local 8km ARW model. Similar to its 12z run, the 18z run parked the band over Porter County into tomorrow afternoon due to mesolow/stalled out convergence axis. Amounts I forecasted would be underdone if that occurs. 18z NAM wasn't that bullish, but convergence and omega parameters I use for LE still suggest it could rip pretty good in at least northeast Porter starting around 9z tonight. My confidence wasn't too high on snow amounts, and it usually isnt with lake effect setups in our NW IN counties, because of the variance in the guidance.
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0z GGEM looked really nice for mby, looks like the band is hanging around Porter County from about 6z-18z Sunday.  I'd be most appreciative of a weenie accumulation map.

 

And the 0z Euro is consistent as well, and come to think of it matches the GGEM rather nicely, with a broader area of snow at 6z (though best convergence into Berrien and LaPorte Counties), and then the band/mesolow sitting right on top of us at 9z and 12z before finally shifting west into Lake County by 15z.

 

Even given the transient nature of the band, the really impressive lake parameters should allow for several inches here Sunday morning with either solution.

 

The GFS is still kinda meh.  Gives the best totals to LaPorte though we'd probably still squeeze out a few inches midday Sunday as the weakening band pushes through.

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We've been getting quality snow, if not legit 1/4SM, since 8:35 a.m.  As of 9:50 a.m., just a paltry 0.6" though.  Sure looks like more but I gotta go with what's on the board.

Not too abnormal.  In my years at MTU we would have these lower visibility snows after some of the arctic front would come through but didn't seem to add up all that much considering the visibilities.  

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AREA FORECAST DISCUSSION  

NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL  

1055 AM CST THU FEB 12 2015  

   

UPDATE  

 

1055 AM CST  

 

BASED ON RADAR AND OBSERVATIONAL TRENDS WITH THE ONGOING LAKE  

EFFECT SNOW...HAVE UPGRADED PORTER COUNTY TO A WINTER STORM  

WARNING IN EFFECT UNTIL EARLY THIS EVENING. SURFACE OBSERVATIONS  

AND SOME HI-RES GUIDANCE TRENDS INDICATE THAT CONVERGENCE AXIS  

WITH WESTERN MOST LAKE EFFECT BAND WILL REMAIN STRONG AND PERSIST  

THROUGH THE AFTERNOON. INVERSION HEIGHTS AND INSTABILITY WILL BE  

COMING DOWN THIS AFTERNOON...BUT EXPECTING AT LEAST 1 TO 2 HOURS  

MORE OF UP TO 1 INCH PER HOUR SNOWFALL RATES BASED ON KLOT AND  

TMDW SHOWING STEADY STREAM OF 25 TO AS MUCH AS 30 DBZ ECHOES.  

EXPECTING RATES MORE ON THE ORDER OF HALF INCH PER HOUR...LOCALLY  

HIGHER...THIS AFTERNOON.  

 

HAD ALREADY RECEIVED MEASURED REPORT FROM VALPARAISO UNIVERSITY OF  

2 INCHES AT 9AM...WITH UNIVERSITY WEBCAM SHOWING HEAVY SNOW/LOW  

VSBY SINCE THEN. ALSO...KVPZ HAS BEEN REPORTING 1/4 SM +SN FOR  

ABOUT AN HOUR NOW. WITH REPORTS ALSO OF SIGNIFICANT BLOWING AND  

DRIFTING SNOW AND NEAR WHITE OUTS AT TIMES...CONCERNED WITH VERY  

SIGNIFICANT TRAVEL IMPACTS...PARTICULARLY I-80/I-94 AND ON US 12.  

WITH EXPECTATION NOW OF LONGER DURATION OF ACCUMULATING SNOW AND  

DANGEROUS TRAVEL...FELT IT PRUDENT TO UPGRADE TO A WINTER STORM  

WARNING. HAVE BUMPED UP SNOWFALL AMOUNTS TO UP TO 5 TO 8 INCHES  

MAINLY NORTHEAST OF A PORTAGE TO KOUTS LINE...BUT AS IS ALWAYS THE  

CASE WITH LAKE EFFECT...THERE WILL BE VARIABILITY IN OBSERVED  

AMOUNTS.  

 

RC  

 

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As far as the weekend, I'm thinking 6-12" for parts of Porter, LaPorte, St. Joseph, Berrien is a good starting point...and possibly Lake county IN as well depending on how long it takes the band to move in there.  Could be higher amounts somewhere, especially if the band stalls out longer than expected, but too early to tell.  Progged veering of low level flow to a greater extent than today should eventually allow the band to make it farther west.  Although thermodynamics become less favorable with time on Sunday, I'd also keep an eye on this farther west in Lake county IN and even near the IL/WI shore, as the wind regime also becomes light and sometimes you can get a surprise right near the shore when that happens.   

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