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Lake Effect Snow Belts Discussion Thread


TugHillMatt

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I saw a 2" LSR from the university as of 9 AM.  Too high?

 

Not sure who reported that.  I'm typically the snow-measuring guy, haha.  Looking out the window this morning and just eyeballing it I would have said that sounded good, but the actual measurement says otherwise.

 

We're up to 2.6" as of 11:50 a.m.; 2.0" exactly in 2 hours.  Snow depth checks out too.  6.5" last night --> 9.0" now.

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The IWX WRF is on board with the GGEM and Euro, and the 12z NAM looked similar too.

 

Looks like a plume or secondary feeder band, like today, into mby after 0z Sunday, then the main band rotates through about 8-12z with heavier snow, then we're done shortly after that.

 

Should be good for 5-10" here.

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The IWX WRF is on board with the GGEM and Euro, and the 12z NAM looked similar too.

 

Looks like a plume or secondary feeder band, like today, into mby after 0z Sunday, then the main band rotates through about 8-12z with heavier snow, then we're done shortly after that.

 

Should be good for 5-10" here.

 

 

Omega off the charts at this time

 

 

post-14-0-43035600-1423775802_thumb.png

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IWX

 

 


MUCH DIFFERENT STORY IN OUR W/NW COUNTIES ONCE LAKE EFFECT RAMPS UP.   700MB TEMPS STILL SHOWN TO DROP TO AROUND -30C BY LATE SATURDAY SO   INVERSION HEIGHTS WILL BE AROUND 10 KFT. 12KM NAM STILL SHOWS A HIGH   DEGREE OF INSTABILITY ALONG ENTIRE STRETCH OF LAKE MICHIGAN WITH   0-2KM DELTA THETA-E VALUES NEAR -5C/KM. FINAL SNOW AMOUNTS WILL   DEPEND GREATLY UPON EXACT EVOLUTION OF NEAR SURFACE WIND FIELD AND   RESULTING ORGANIZATION OF LAKE INDUCED CONVECTIVE BAND(S). STRONG   GRADIENT WITH A 330-340 DEGREE FETCH SATURDAY EVENING WILL INITIALLY   PREVENT A SINGLE/DOMINANT BAND FROM SETTING UP. WILL PROBABLY SEE A   FEW BANDS DURING THIS TIME...THOUGH STILL CAPABLE OF PRODUCING   MODERATE/HEAVY SNOW GIVEN HIGH DEGREE OF INSTABILITY. SITUATION   CHANGES OVERNIGHT AS LOW LEVEL WINDS VEER SLIGHTLY AND GRADIENT   RELAXES. NOT ONLY DOES THIS ALLOW A LAKE-INDUCED PRESSURE TROUGH AND   MIDLAKE CONVERGENT BAND TO SET UP BUT ALSO ALLOWS FOR EXCELLENT LAKE   SUPERIOR CONNECTION PER LATEST NAM12 PLUME ANALYSIS. SHOULD   THEREFORE SEE A HEFTY DOMINANT BAND SET UP SATURDAY NIGHT BUT THE   PROBLEM IS THAT LOW LEVEL WINDS CONTINUE TO SLOWLY VEER THROUGH   SUNDAY MORNING...KEEPING THE BAND FROM REMAINING IN ANY ONE   PARTICULAR LOCATION AND EVENTUALLY SHIFTING IT OUT OF OUR CWA   ALTOGETHER. EVENT IS STILL 60-72 HOURS AWAY SO CONFIDENCE IN THESE   FINE SCALE DETAILS IS NOT HIGH. WILL STICK WITH A CONSERVATIVE 2-6   INCH ACCUMULATION FOR NOW. AS IS ALWAYS THE CASE WITH LAKE EFFECT   EVENTS...AMOUNTS WILL BE HIGHLY VARIABLE AND ONLY A FEW ISOLATED   LOCATIONS MAY SEE THE HIGHER END ACCUMULATIONS.  
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LOT

 


LAKE EFFECT DISCUSSION FOR SATURDAY INTO SUNDAY...EXTREME 850 MB TO   LAKE DELTA TS OF ABOUT 25C AND EQUILIBRIUM LEVELS AT OR OVER 10KFT   ARE LIKELY TO RESULT IN IMPRESSIVE LAKE EFFECT SNOW BAND(S) DEVELOPING  OVER SOUTHERN LAKE MICHIGAN. WILL STILL NEED TO ASSESS LATEST GUIDANCE  CONCERNING OVERALL EVOLUTION...BUT GUIDANCE HAS REMAINED IN  EXCELLENT AGREEMENT IN SWINGING BOUNDARY LAYER FLOW FROM NNW  SATURDAY AFTERNOON AND EARLY EVENING TO NORTHERLY SATURDAY NIGHT  AND THEN NORTH-NORTHEAST TO NORTHEAST ON SUNDAY. STEADY LAKE SNOWS  COULD GET INTO PORTER COUNTY AS EARLY AS SATURDAY AFTERNOON. I  THEN BROUGHT CATEGORICAL POPS WESTWARD SATURDAY NIGHT INTO SUNDAY  MORNING...WITH ACTIVITY WEAKENING OVER NORTHEAST ILLINOIS DUE TO  SUBSIDENCE AND INCREASINGLY DRY AIR ON SUNDAY AFTERNOON. POTENTIAL  MESOLOW/ENHANCED CONVERGENCE COULD LET SNOW HANG ON A BIT LONGER  THAN WOULD OTHERWISE EXPECT. WILL LIKELY NEED SOME SORT OF LAKE  EFFECT HEADLINE AND WOULDNT BE SURPRISED WITH NEEDING ANOTHER  WARNING FOR AT LEAST PORTER COUNTY GIVEN IMPRESSIVE PARAMETERS. AT  LEAST 6 INCHES OF ACCUMULATION APPEAR POSSIBLE FOR THE NORTHERN  HALF OF PORTER...WHICH COULD BE CONSERVATIVE.    RC  
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I've been surprised by how consistently low the QPF output on the mesoscale models has been as well.  I remember there being something like a 1.5" signal before the Jan 2014 event. 

 

 

Do you remember which model?  I think the IWX WRF was too low with amounts and playing catchup but can't remember the others.  In this case though, we're not really seeing any mesoscale model going nuts.

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Gonna be interesting to see what flake size is like.  With the really cold airmass and strong winds early on, hard to be optimistic in that regard.  I'm curious if there will be enough low level temperature modification within the band to allow for better dendrite survival to the ground, especially once winds slacken, as models have 925 mb temps flirting with the edge of the favorable dendritic growth temp (around -18C) in the band. 

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I posted this over in the banter thread, but despite its inherent whininess it also contains some interesting stats, so what the heck...

 

 

 

Valparaiso has had lake-effect events that produced at least 10 inches of snow in (at least) December 2004, February 2008, November 2008, February 2009, December 2010, and January 2011, this not including any synoptic-scale systems that happened to produce significant lake enhancement.
 
Since I arrived in the fall of 2011, there have been precisely zero.  Barring some fantastic model bust tomorrow night, or some other unforeseen event in the roughly ten days we have left in the season, my class will be the first since *at least* the class of 2004 to go all four years without a big lake-effect event.  And I only looked even semi-exhaustively back to 2007.  This record could easily go back into the 1990s.
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I posted this over in the banter thread, but despite its inherent whininess it also contains some interesting stats, so what the heck...

Valparaiso has had lake-effect events that produced at least 10 inches of snow in (at least) December 2004, February 2008, November 2008, February 2009, December 2010, and January 2011, this not including any synoptic-scale systems that happened to produce significant lake enhancement.

Since I arrived in the fall of 2011, there have been precisely zero. Barring some fantastic model bust tomorrow night, or some other unforeseen event in the roughly ten days we have left in the season, my class will be the first since *at least* the class of 2004 to go all four years without a big lake-effect event. And I only looked even semi-exhaustively back to 2007. This record could easily go back into the 1990s.

How much fell there in February 2012? I recall we had 10"+ reports from Porter County. Despite the impressive instability parameters, I think some of the aspects that are likely to keep this event in check relatively speaking have been mentioned already, strong winds and airmass almost too cold for good flake size. In addition, equilibrium levels are great, but inversion heights are only progged to be 5 to 7kft, so not quite what you'd want for widespread 1'+ amounts. I still think some spots, probably in LaPorte or Berrien, could tag ~8-9". The 12z run of the national ARW also had some decent qpf into Porter.

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How much fell there in February 2012? I recall we had 10"+ reports from Porter County. Despite the impressive instability parameters, I think some of the aspects that are likely to keep this event in check relatively speaking have been mentioned already, strong winds and airmass almost too cold for good flake size. In addition, equilibrium levels are great, but inversion heights are only progged to be 5 to 7kft, so not quite what you'd want for widespread 1'+ amounts. I still think some spots, probably in LaPorte or Berrien, could tag ~8-9". The 12z run of the national ARW also had some decent qpf into Porter.

 

I think 5.5" got reported here, including around 1" of Clipper snow, though my own measurements came up short of that.

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Radar looks really unimpressive.  Just some pretty light snow showers coming off the lake.  Even the main band doesn't look that impressive on GRR's radar.  I mean it's probably still 1-2"/hr out there but nothing dramatic.

 

The latest HRRR doesn't even get us to a tenth.

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Radar looks really unimpressive.  Just some pretty light snow showers coming off the lake.  Even the main band doesn't look that impressive on GRR's radar.  I mean it's probably still 1-2"/hr out there but nothing dramatic.

 

The latest HRRR doesn't even get us to a tenth.

Best window for better organization has been later this evening into the overnight as the flow starts to relax a bit and the fetch becomes parallel to the long axis, so we'll see, but inversion starts lowering by then. 

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IWX pulled the trigger on a blizzard warning

 

 

 


URGENT - WINTER WEATHER MESSAGE  NATIONAL WEATHER SERVICE NORTHERN INDIANA  324 PM EST SAT FEB 14 2015    INZ003>005-MIZ077-078-150430-  /O.CAN.KIWX.WS.W.0005.000000T0000Z-150215T1200Z/  /O.NEW.KIWX.BZ.W.0001.150214T2024Z-150215T0300Z/  /O.NEW.KIWX.WS.W.0006.150215T0300Z-150215T1200Z/  LA PORTE-ST. JOSEPH IN-ELKHART-BERRIEN-CASS MI-  INCLUDING THE CITIES OF...MICHIGAN CITY...LA PORTE...SOUTH BEND...  MISHAWAKA...NEW CARLISLE...WALKERTON...ELKHART...GOSHEN...  NAPPANEE...NILES...BENTON HARBOR...ST. JOSEPH...BUCHANAN...  DOWAGIAC...CASSOPOLIS...MARCELLUS  324 PM EST SAT FEB 14 2015 /224 PM CST SAT FEB 14 2015/    ...BLIZZARD WARNING IN EFFECT UNTIL 10 PM EST /9 PM CST/ THIS  EVENING...  ...WINTER STORM WARNING IN EFFECT FROM 10 PM EST /9 PM CST/ THIS  EVENING TO 7 AM EST /6 AM CST/ SUNDAY...    THE NATIONAL WEATHER SERVICE IN NORTHERN INDIANA HAS ISSUED A  BLIZZARD WARNING...WHICH IS IN EFFECT UNTIL 10 PM EST /9 PM CST/  THIS EVENING. A WINTER STORM WARNING HAS ALSO BEEN ISSUED. THIS  WINTER STORM WARNING FOR SNOW AND BLOWING SNOW IS IN EFFECT FROM  10 PM EST /9 PM CST/ THIS EVENING TO 7 AM EST /6 AM CST/ SUNDAY.    HAZARDOUS WEATHER...     * TIMING...BANDS OF MODERATE TO HEAVY LAKE EFFECT SNOW WILL     CONTINUE THROUGH THIS EVENING.     * SNOW ACCUMULATIONS...GENERALLY RANGING BETWEEN 3 AND 7      INCHES. DUE TO THE NATURE OF LAKE EFFECT SNOW...EXACT TOTALS      MAY VARY SIGNIFICANTLY DEPENDING ON WHERE THE HEAVIER      SNOWBANDS SET UP.      * BLOWING SNOW...SNOWFALL WILL BE ACCOMPANIED BY VERY STRONG     WINDS TODAY...DIMINISHING TONIGHT...WITH NORTHWEST GUSTS AS     HIGH AS 40 TO 45 MPH THROUGH THIS AFTERNOON. THE STRONG WINDS     WILL RESULT IN WHITEOUT CONDITIONS AT TIMES. EVEN LOCATIONS     WHICH DO NOT RECEIVE THE HEAVIER SNOWFALL WILL LIKELY     EXPERIENCE PERIODIC WHITEOUT CONDITIONS THROUGH EARLY THIS     EVENING BEFORE WINDS BEGIN TO SUBSIDE.     * DANGEROUS COLD...WIND CHILLS ARE EXPECTED TO FALL TO BETWEEN      10 BELOW AND 20 BELOW ZERO TONIGHT INTO SUNDAY MORNING.     IMPACTS...     * VISIBILITIES WILL BE REDUCED TO NEAR ZERO AT TIMES WITH     WHITEOUT CONDITIONS.     * STRONG WINDS GUSTING UP TO 45 MPH SATURDAY MAY RESULT IN SOME      POWER OUTAGES.      * BITTERLY COLD WIND CHILLS MAY LEAD TO FROST BITE IN 30      MINUTES OR LESS.   
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