Thunder Road Posted November 9, 2013 Share Posted November 9, 2013 There is significant model consensus that the first major cold shot of the season will hit next week as a >1044 mb High plunges southeastward into the Northern Plains. It looks like there will be some rain and snow showers associated with the cold front Monday, but immediately following the frontal passage, northerly winds and sfc-850 mb delta T values over Lake Michigan of 20-22 C will likely support lake-effect snow showers consolidating into one main band by Tuesday morning, affecting at least part of Northwest Indiana. Though at the very end of its run, the NAM currently suggests that most of the snow would be concentrated over LaPorte and South Bend, while the GFS and Euro show significantly less of a westerly component to the winds, and hence, much more snow for Porter County, and perhaps eastern Lake County (IN) as well. Discuss. Link to comment Share on other sites More sharing options...
Geos Posted November 9, 2013 Share Posted November 9, 2013 Here's what the EURO is showing for the wind direction at the peak time for LES. RPM is showing snow accumulation further west associated with the lake. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted November 9, 2013 Share Posted November 9, 2013 The 0z GFS is a little more bullish for some good snow showers and maybe even an inch in spots behind the front Monday afternoon across northern IL and northwest IN before the LES takes over. Link to comment Share on other sites More sharing options...
Thunder Road Posted November 9, 2013 Author Share Posted November 9, 2013 The 0z GFS is a little more bullish for some good snow showers and maybe even an inch in spots behind the front Monday afternoon across northern IL and northwest IN before the LES takes over. Yup. Very similar to the 18z run up through 18z Tuesday, then the new runs actually appears to increase the westerly component by 18z Tues. As modeled, a nice spread-the-wealth event with Porter getting it at 0z and again at 12z, Lake Co. at 6z, and then finally LaPorte by 18z. The transience of the band would probably keep totals down, but hey, any accumulating snow on November 12th is great in my book! Link to comment Share on other sites More sharing options...
Geos Posted November 9, 2013 Share Posted November 9, 2013 Zoomed in moisture map for the GFS. Approaching 0.40" in Valpo. Link to comment Share on other sites More sharing options...
Hoosier Posted November 9, 2013 Share Posted November 9, 2013 Yup. Very similar to the 18z run up through 18z Tuesday, then the new runs actually appears to increase the westerly component by 18z Tues. As modeled, a nice spread-the-wealth event with Porter getting it at 0z and again at 12z, Lake Co. at 6z, and then finally LaPorte by 18z. The transience of the band would probably keep totals down, but hey, any accumulating snow on November 12th is great in my book! I'm rooting for the stall scenario...I want to see what this thing can do if it parks in the same area, but I realize that wouldn't be good if it isn't over Valpo. I wouldn't be surprised if there's thundersnow embedded given the magnitude of the instability and lake enduced EL heights near 10k. Link to comment Share on other sites More sharing options...
Geos Posted November 9, 2013 Share Posted November 9, 2013 ORD sounding at 66 hours. Link to comment Share on other sites More sharing options...
Thunder Road Posted November 9, 2013 Author Share Posted November 9, 2013 Zoomed in moisture map for the GFS. Approaching 0.40" in Valpo. LES_GFS96.png The raw data is 0.40" http://wxweb.meteostar.com/sample/sample.shtml?text=KVPZ You can actually see the relative lull around 6z. The KORD data spitting out 0.19" suggests that only ~0.21" of the Valpo QPF is actually LES, but that's pretty normal for a global-scale model. (The other interesting note is that, yes, that 0.19" synoptic QPF at KORD, which with the temp profiles given, would be 1.5" of just synoptic snow there, assuming it all accumulates at 10:1.) Link to comment Share on other sites More sharing options...
Thunder Road Posted November 9, 2013 Author Share Posted November 9, 2013 Ok well it's a Friday night on a college campus, so I'll be back later tonight. Keep me posted on the rest of the 0z suite though guys! Link to comment Share on other sites More sharing options...
WestCoaster Posted November 9, 2013 Share Posted November 9, 2013 Zoomed in moisture map for the GFS. Approaching 0.40" in Valpo. LES_GFS96.png Loving that bullseye of nada right over YYZ Still have yet to see any flakes here Link to comment Share on other sites More sharing options...
Geos Posted November 9, 2013 Share Posted November 9, 2013 0z GGEM Link to comment Share on other sites More sharing options...
Geos Posted November 9, 2013 Share Posted November 9, 2013 GGEM says Michigan City, just west of SBN, and La Porte will be the prime target zone for LES. Western UP and NE OH not doing bad either. Link to comment Share on other sites More sharing options...
Thunder Road Posted November 9, 2013 Author Share Posted November 9, 2013 Anyone have the raw text off the Euro? Looks like a good 9-12 hours of LES for mby. Link to comment Share on other sites More sharing options...
Geos Posted November 9, 2013 Share Posted November 9, 2013 NAM is showing a 0.50" bullseye near Michigan City. Joe could probably get the raw numbers for you Thunder Road. Link to comment Share on other sites More sharing options...
Thunder Road Posted November 9, 2013 Author Share Posted November 9, 2013 12z NAM took a big step toward the GFS, backing off on the NW flow. It now has what the GFS had at 0z, with periods of LES for all three NW IN counties at one time or another. Link to comment Share on other sites More sharing options...
Thunder Road Posted November 9, 2013 Author Share Posted November 9, 2013 NAM is showing a 0.50" bullseye near Michigan City. Joe could probably get the raw numbers for you Thunder Road. Verbatim, I see 0.29" at VPZ. http://68.226.77.253/text/NAM80km/NAM_KVPZ.txt I thought Michigan City was MGC, but that particular site doesn't want to produce output for that code, so I don't know. Link to comment Share on other sites More sharing options...
Jonger Posted November 9, 2013 Share Posted November 9, 2013 Bo is going to get hammered, maybe 18 inches. Link to comment Share on other sites More sharing options...
Geos Posted November 9, 2013 Share Posted November 9, 2013 12z GFS more N-S with LES area. EURO throws back snow west of Lake Michigan like the 0z GFS. Link to comment Share on other sites More sharing options...
Hoosier Posted November 9, 2013 Share Posted November 9, 2013 12z NAM took a big step toward the GFS, backing off on the NW flow. It now has what the GFS had at 0z, with periods of LES for all three NW IN counties at one time or another. Given all the data, if I had to guess, I'd say that the area most likely to receive 6" or more would be Porter county with parts of Lake and LaPorte also not out of it. I'm not sure this will be the typical high ratio superfluff but the only part of the column near freezing is right near the ground so ratios may still be pretty decent with a possible exception being near the shore. Link to comment Share on other sites More sharing options...
Heisy Posted November 9, 2013 Share Posted November 9, 2013 Pretty impressive low near the Lakes on the day Day 10 EURO, 2 runs in a row just a FYI Link to comment Share on other sites More sharing options...
weatherbo Posted November 9, 2013 Share Posted November 9, 2013 Bo is going to get hammered, maybe 18 inches.woo hoo! that would be great. APX is mentioning "significant accums" along and west of 131, in a NNW flow event. that's one of the best flows for my specific area because you can get a single band connection to superior, rather than just moisture from superior. Link to comment Share on other sites More sharing options...
Jonger Posted November 9, 2013 Share Posted November 9, 2013 Bo is going to get hammered, maybe 18 inches.woo hoo! that would be great. APX is mentioning "significant accums" along and west of 131, in a NNW flow event.that's one of the best flows because you can get a single band connection to superior, rather than just moisture from superior. My sled is done, got the call around noon. There won't be anything to track here, I will pay a bit more attention to this one. Usually +.75 inches of QPF verifies 18 inches LES. Link to comment Share on other sites More sharing options...
Thunder Road Posted November 9, 2013 Author Share Posted November 9, 2013 AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL 323 PM CST SAT NOV 9 2013 ... WITH THIS COLDER AIR BARRELING DOWN THE LAKE...MORE THAN FAVORABLE THERMODYNAMIC CONDITIONS WILL PROVIDE A GOOD SETUP FOR LAKE EFFECT PRECIP MONDAY NIGHT INTO TUESDAY...AND AM GROWING A LITTLE CONCERNED FOR THE POSSIBILITY FOR SIGNIFICANT SNOW ACCUMULATIONS ACROSS NORTHWEST INDIANA. A LONG FETCH DOWN THE LAKE WITH A FAVORABLE SYNOPTIC PATTERN/CYCLONIC FLOW SHOULD ALLOW FOR AN EXTENDED PERIOD OF LAKE EFFECT PRECIP TO PERSIST BEHIND THE SYSTEM PRECIP...WITH A RAIN/SNOW MIX MORE PROBABLE LATE MONDAY AFTERNOON BEFORE A QUICK TRANSITION TO ALL SNOW IS LIKELY TO BE OBSERVED EARLY MONDAY EVENING INTO TUESDAY. BOUNDARY LAYER FLOW WILL KEEP ANY PRECIP IN NORTHWEST INDIANA...WITH PORTER COUNTY THE MORE PREFERRED LOCATION TO OBSERVE LES SNOW/SNOW BAND. DONT WANT TO GET INTO ANY AMOUNTS SINCE SMALLER SCALE FEATURES/RESIDENCE TIME OF ANY LES BAND WILL DICTATE SNOWFALL TOTALS...BUT THERE DOES APPEAR TO BE A DEFINITE POSSIBILITY FOR ADVISORY TYPE SNOWFALL ACROSS AT LEAST PORTER COUNTY WITH LOCALLY HIGHER AMOUNTS DEFINITELY NOT OUT OF THE QUESTION. RODRIGUEZ Link to comment Share on other sites More sharing options...
Geos Posted November 9, 2013 Share Posted November 9, 2013 18z GFS moisture through 72 hours. Link to comment Share on other sites More sharing options...
Hoosier Posted November 9, 2013 Share Posted November 9, 2013 At least we are starting to get into the time range of some of the hi-res models, though they have their own biases to contend with. IWX AS COLD AIR DEEPENS MONDAY NIGHT AND FLOW QUICKLY BECOMES NORTHERLY...FOCUS SHIFTS TO LAKE EFFECT SNOW AND POTENTIAL FOR ACCUMULATIONS. MID LAKE TEMPERATURES HOVERING AROUND 10C PER MID LAKE BUOY AND THIS YIELDS SFC-850MB DELTA T VALUES AROUND 20C MONDAY NIGHT WITH SFC-700MB VALUES APPROACHING CRITICAL 30C LEVEL WHICH IS A GOOD INDICATOR FOR SIGNIFICANT ACCUMULATIONS. NAM12 SHOWING GOOD MOISTURE THROUGH 6-8KFT BUT THE ONE LIMITING FACTOR LOOKS TO BE SIGNIFICANT DRYING ABOVE 10KFT AS DRY CP AIRMASS BUILDS SOUTHWARD. HOWEVER...NORTHERLY TRAJECTORIES SUGGEST PRECONDITIONING OFF OF LAKE SUPERIOR A POSSIBILITY AND GIVEN ABUNDANT LOW LEVEL MOISTURE SHOULD STILL BE ABLE TO GENERATE A SIGNIFICANT SINGLE BAND MONDAY NIGHT INTO TUESDAY MORNING. NAM12 TRAJECTORIES SHOWING A MEANDERING NATURE TO BAND DEVELOPMENT WITH OFFSHORE FLOW LIKELY PUSHING BAND INTO EXTREME SOUTHWEST BERRIEN COUNTY AND WESTERN LAPORTE COUNTY. FOR NOW HAVE INCREASED POPS IN THESE AREAS TO HIGH END LIKELY WITH UNCERTAINTY LEFT TO ACTUAL BAND PLACEMENT. WITH JUST A BIT MORE VEERING OF LOW LEVEL FLOW...BAND COULD PUSH WEST INTO KLOT CWA. DID INCREASE SNOW AMOUNTS ACROSS WESTERN BERRIEN AND LAPORTE COUNTIES AS WELL AS WESTERN STARKE GIVEN FAVORABLE OVERNIGHT TIMING AND EXTREME INSTABILITY. MORE REFINEMENT LIKELY NEXT 48 HOURS AS HIGHER RES GUIDANCE COMES INTO PLAY. SEVERAL INCHES OF SNOW POSSIBLE WITH HEADLINES OF SOME TYPE NOT OUT OF QUESTION. Link to comment Share on other sites More sharing options...
Hoosier Posted November 9, 2013 Share Posted November 9, 2013 For southern Lake Michigan, the most favorable parameters seem to occur early Tuesday before becoming less favorable with time, though these things often seem to wind down a bit slower than progged. Trajectories on Tuesday morning would seem to favor Porter county which is why I'm most bullish about that area. In addition, the band may spend the most amount of time there even with shifting. Link to comment Share on other sites More sharing options...
slow poke Posted November 10, 2013 Share Posted November 10, 2013 woo hoo! that would be great. APX is mentioning "significant accums" along and west of 131, in a NNW flow event. that's one of the best flows for my specific area because you can get a single band connection to superior, rather than just moisture from superior. Same with the area where our cabin is at. A 340ish wind direction is what we need for a good Lake Superior connection and have the wind strong enough to push that heavy "firehose" band inland enough to nail us. It happened last year when we got over a foot the day after Thanksgiving. Heck, I would be happy with just some tracking snow for opening weekend of firearm deer season. Link to comment Share on other sites More sharing options...
Jonger Posted November 10, 2013 Share Posted November 10, 2013 18z GFS moisture through 72 hours. zoomGFS111213.png I know I'm going to get roasted for saying this, but the NAM does better with LES than the GFS. I plan my LES chases based on the NAM and it never fails when within 48 hours. Link to comment Share on other sites More sharing options...
Trent Posted November 10, 2013 Share Posted November 10, 2013 For LES, you can't really rely on the global models for the specifics; sure they have their purpose for general parameters, but for getting down to the nitty gritty, the hi-res models are the way to go. Once you learn their biases and account for those, you can really nail down accums and areas that will get hit. Luckily, for those of us in the eastern lakes, the NWS in Buffalo has some great local models. So far for the two lake effect events that have hit Northeast Ohio this season (parts of eastern Cuyahoga County are already sitting at 9" for the season), they've been quite good. They might have done some upgrades over the summer: http://www.erh.noaa.gov/buf/mm/mesomodels.html Link to comment Share on other sites More sharing options...
IWXwx Posted November 10, 2013 Share Posted November 10, 2013 Here's IWX's in-house model's precip total (NAM initiated). I have found it to be fairly accurate with trajectory for Lake MI LES events. Oh, and the zoomed out version for those affected in MI and part of OH: Link to comment Share on other sites More sharing options...
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