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Early Season Lake Effect and Clippers


Geos

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That's right I did it.  Here's the first 18hr RAP posting of the event lol. 

 

snip~

 

Get the edge of the 30dbz to the border and I be happy!

 

Anyone post this yet...

 

File.png

 

NAM sounding near Elgin at 4pm tomorrow.

 

NAM_218_2013102118_F27_42.0000N_88.5000W

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Last several runs of the RAP have trended weaker and a bit farther south with the clipper(for Iowa), and now the 00z NAM is drier and a bit farther south as well.  Most models now don't have much more than a tenth or so liquid for CR, so it shouldn't amount to much.  Still, it'll be nice to see some snow.

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ummm...

FINALLY...AM BUMPING UP POPS SOME TUESDAY NIGHT OVER PORTER COUNTY
INDIANA AS A VERY IMPRESSIVE LOOKING LAKE EFFECT SET-UP DEVELOPS.
LAKE-850MB DELTA-T VALUES >20C...LAKE INDUCED CAPE OVER 1000
J/KG...EQUILIBRIUM LEVELS OVER 20KFT...AND IMPRESSIVE LAND BREEZE
CONVERGENCE ZONE ALL POINT TO THE POTENTIAL FOR HEAVY LAKE EFFECT
PRECIPITATION AND EVEN POSSIBLE ISOLD THUNDERSTORMS. RELATIVELY WARM
LAKE WILL PROBABLY MEAN LITTLE IF ANY ACCUM NEAR THE SHORE WITH RAIN
OR SNOW AS P-TYPE...BUT ANY LAKE EFFECT THAT MOVES INLAND A WAYS
SHOULD BE ALL SNOW WITH SOME ACCUMULATIONS POSSIBLE. NOT PLANNING TO
ADDRESS THIS POTENTIAL WITH EVENING UPDATE...JUST GOING TO PASS
CONCERNS ON THE MIDNIGHT SHIFT TO HANDLE.

IZZI

bullish to say the least, imo.

 

There should be a nice plume, sure, but I'm pretty skeptical of accums.

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Usually when you get to this point before an event you can make a forecast for amounts that's pretty confident.  With the narrow nature of the snow swath, combined with the seasonal factors it's pretty tough.  I'm just gonna go with an inch for here and the QC.  It's possible more than that will actually fall, but don't think we'll actually accumulate more than an inch or so.  Looking forward to whatever happens nonetheless.

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NAM HIRES initialized too far west and south. Showing the center of the band towards the MO River, which isn't the case. If the snow band comes in a bit northeast of Sioux Falls, Cyclone to MDW should be more center in reality.

 

rad3.gif

 

Good disco by Izzi.

 

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
838 PM CDT MON OCT 21 2013

.DISCUSSION...
838 PM CDT

NO BIG CHANGES PLANNED TO GOING FORECAST FOR TONIGHT OR FOR SYSTEM
TUESDAY. THE 18Z WRF-NAM DID SHIFT NORTHWARD WITH THE SYSTEM PLACING
ITS SOLUTION ON THE NORTHERN EXTENT OF THE GUIDANCE ENVELOPE...WITH
THE ECMWF/GFS BOTH CONTINUING TO PEG ABOUT THE SOUTHERN HALF OF OUR
CWA WITH THE MOST SIGNIFICANT PRECIPITATION. PRECIPITATION SHOULD BE
DRIVEN LARGELY BY FAIRLY IMPRESSIVE LOW/MID LEVEL FRONTOGENETIC
CIRCULATION WHICH WILL PROBABLY RESULT IN A FAIRLY SHARP CUT OFF TO
THE PRECIP ON THE NORTHERN EDGE. GOING FORECAST IS VERY MUCH IN LINE
WITH THE CONSISTENT GFS/ECMWF SOLUTIONS WHICH IS FARTHER SOUTH THAN
THE NAM AND WHERE THE GOOD MONEY BET SHOULD BE.

P-TYPE FORECAST IS A HAIRY MESS. MODELS HAVE BEEN VERY CONSISTENT
FOR DAYS NOW IN FORECASTING THE COLUMN TO COOL SUFFICIENTLY VIA
EVAPORATION AND ASCENT TO RESULT IN A CHANGE OVER TO WET
SNOW...PARTICULARLY WHERE THE HEAVIEST PRECIP FALLS. CERTAINLY
CLIMO AND TIME OF DAY WOULDN`T FAVOR A SWITCH OVER TO SNOW LET
ALONE ANY ACCUMULATION...BUT WITH SUCH STRONG MODEL AGREEMENT AND
CONSISTENCY ITS SEEMING MORE AND MORE PLAUSIBLE THAT A CHANGE OVER
TO WET SNOW WILL OCCUR. MID LEVEL LAPSE RATES ARE PROGGED TO BE
FAIRLY STEEP (>7C/KM) TUESDAY AFTERNOON WHICH ALSO RAISES THE
POSSIBILITY THAT THERE COULD BE SOME CONVECTIVE ELEMENTS EMBEDDED
WITHIN THE PRECIP TUESDAY AFTERNOON...MAINLY OVER IOWA INTO THE
WESTERN HALF OF ILLINOIS WHERE INSTABILITY AND FORCING APPEAR TO
BE A BIT MORE IMPRESSIVE. ANY CONVECTIVE ENHANCEMENT TO THE PRECIP
WILL ONLY FURTHER HELP COOL THE COLUMN AND INCREASE THE CHANCE OF
A SWITCH OVER TO WET SNOW.

WHEREEVER (AND IF) SNOW FALLS HARD ENOUGH THERE COULD BE SLUSHY
ACCUMULATIONS...MAINLY ON GRASSY AND ELEVATED SURFACES. NOT EVEN
TOTALLY OUT OF THE QUESTION THAT THERE COULD BE A NARROW BAND OF A
COUPLE INCHES OF SLUSHY ACCUMULATIONS...MAINLY SOUTHERN HALF OF
THE CWA...BUT THAT WILL BE MORE OF NOWCAST TYPE SITUATION TUESDAY
GIVEN THE LIKELY VERY LIMITED AREAL EXTENT OF SUCH ACCUMULATIONS
TAKING PLACE (LIKELY ON THE ORDER OF LESS THAN 30MI WIDE BAND).


FINALLY...AM BUMPING UP POPS SOME TUESDAY NIGHT OVER PORTER COUNTY
INDIANA AS A VERY IMPRESSIVE LOOKING LAKE EFFECT SET-UP DEVELOPS.
LAKE-850MB DELTA-T VALUES >20C...LAKE INDUCED CAPE OVER 1000
J/KG...EQUILIBRIUM LEVELS OVER 20KFT...AND IMPRESSIVE LAND BREEZE
CONVERGENCE ZONE ALL POINT TO THE POTENTIAL FOR HEAVY LAKE EFFECT
PRECIPITATION AND EVEN POSSIBLE ISOLD THUNDERSTORMS. RELATIVELY WARM
LAKE WILL PROBABLY MEAN LITTLE IF ANY ACCUM NEAR THE SHORE WITH RAIN
OR SNOW AS P-TYPE...BUT ANY LAKE EFFECT THAT MOVES INLAND A WAYS
SHOULD BE ALL SNOW WITH SOME ACCUMULATIONS POSSIBLE. NOT PLANNING TO
ADDRESS THIS POTENTIAL WITH EVENING UPDATE...JUST GOING TO PASS
CONCERNS ON THE MIDNIGHT SHIFT TO HANDLE.

IZZI

 

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The 00z NAM and some of the latest RAP precip type algorithms keep the precip more in the form of rain tomorrow.  The models had been very consistent up until this run, but appear to be crapping out the snow potential at the last minute.  Hopefully this is just a bad run, and not a sign of a trend.  If so my 1" call for the QC won't even be close.

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If the GFS has anything to say about it, the Quad Cities area looks primed for a solid October snowfall.  After the last couple of tough years there, it would be nice for Cyclone to see a surprise October snow event.  Then again, the GFS is borderline, and the NAM a bit warmer as Cyclone mentioned above.

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Had a nice burst of snow for about 20 minutes earlier, with a nice coating now covering things. Measured just shy of a half inch. Webcam view from the house:

 

webcam.jpg

 

Nice.  What type of camera do you have for this setup?  I would like to get a cam set up at some point.  Maybe this winter.

 

Even though things don't look quite as good for actual accums here tomorrow, will get the time lapse set up just in case.  My grass is actually pretty long at the moment, as I haven't made the last cut of the season.  That should hopefully help whatever falls accumulate tomorrow lol.

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Nice.  What type of camera do you have for this setup?  I would like to get a cam set up at some point.  Maybe this winter.

 

Even though things don't look quite as good for actual accums here tomorrow, will get the time lapse set up just in case.  My grass is actually pretty long at the moment, as I haven't made the last cut of the season.  That should hopefully help whatever falls accumulate tomorrow lol.

It's actually an older Toshiba security camera a couple forecasters and I came across when I was down at the NWS office in Blacksburg, VA. I think it's the IK-WBO11A model, and it's been one heck of a camera. Had it outside for its entire life the past 10 years with no problems whatsoever. Does some great night/low-light shots and it completely internet-controllable. Check it out here (really snowing hard as I type this):

 

http://97.83.48.133:9000/user_view_S.htm

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