Hoosier Posted November 12, 2022 Share Posted November 12, 2022 Folks, it's time. Likely not too big of a system, but it looks pretty widespread and we're less than 5 days away. 2 1 Link to comment Share on other sites More sharing options...
Hoosier Posted November 12, 2022 Author Share Posted November 12, 2022 Details on the interaction with the northern stream will be sorted out, but we at least have a pretty respectable southern stream wave being progged. This wave is currently around the coast of Oregon. Link to comment Share on other sites More sharing options...
cyclone77 Posted November 12, 2022 Share Posted November 12, 2022 Ahhh, the first snow thread of the season. Nice to see a spread the wealth type of system to kick things off as well. 1 Link to comment Share on other sites More sharing options...
RogueWaves Posted November 12, 2022 Share Posted November 12, 2022 DTX - Oh the dreaded and ever-present sensitivity to track concerns around here - sigh High pressure is on schedule to build across the Great Lakes byMonday to start the week with dry weather. The high holds intoTuesday as the next low pressure system gathers organization overthe Plains and Midwest. This large and intense system sweeps Gulfmoisture northward which could reach Lower Mi as early as Tuesdayafternoon in the form of a rain/snow mix. A heavier mix of rain andsnow changing to all snow becomes possible Tuesday night intoWednesday as extended range models show the surface low centertracking nearby across NW Ohio, a track that makes the forecast forSE MI very sensitive to the small adjustments likely in upcomingforecast cycles. Link to comment Share on other sites More sharing options...
A-L-E-K Posted November 12, 2022 Share Posted November 12, 2022 Would be lightly hyped if cold, but since warm and winds off lake going dab Nice to see euro still the premier fantasy snow model Link to comment Share on other sites More sharing options...
Hoosier Posted November 12, 2022 Author Share Posted November 12, 2022 11 minutes ago, A-L-E-K said: Would be lightly hyped if cold, but since warm and winds off lake going dab Nice to see euro still the premier fantasy snow model Probably a decent call for your backyard. Assuming lake temps are still near 50 by Tuesday morning (nearshore temps are currently ~53), that is often going to be a problem when winds are onshore and 850 mb temps "only" around -7C to -8C. The low level flow does not look that strong, so the marine influence shouldn't extend too far inland (ORD/MDW should largely be safe from it imo), but lakeside will be battling. Link to comment Share on other sites More sharing options...
Hoosier Posted November 12, 2022 Author Share Posted November 12, 2022 Quality afd from RC considering it's a modest system. 1 Link to comment Share on other sites More sharing options...
Hoosier Posted November 13, 2022 Author Share Posted November 13, 2022 Sort of tricky to figure out where the highest amounts will be in LOT's area. There is a lake signal showing up (trending more favorable toward nw IN with time) but that will be countered by warmer low level temps near the lake. If I had to bet I'd go with somewhere a little inland in northwest IN by the time it's all done but not the greatest confidence. 1 Link to comment Share on other sites More sharing options...
Hoosier Posted November 13, 2022 Author Share Posted November 13, 2022 Poor Alek I feel like the inland extent of the marine influence is overdone on here though. Don't think the freezing line will be all the way in McHenry county at that time. Link to comment Share on other sites More sharing options...
Hoosier Posted November 13, 2022 Author Share Posted November 13, 2022 Granted it's the NAM at 84 hours, but just showing it to make a general point as ultimate location may be different. We can use the 850 mb vertical velocity output as a proxy for the lake effect band location, and as you can see, there's a strong signal in and around Porter county Indiana on the NAM at that time. Pulling a forecast sounding from northern Porter county reveals a deep layer of relatively steep lapse rates and good moisture in the low-mid levels, so we're working with very good inversion heights and implied lake-induced EL heights if modifying for lake water temps. Getting precip won't be a problem. The bigger question is how far inland will you have to go to get away from the marine warmth, thus having some better accumulation potential. Link to comment Share on other sites More sharing options...
RogueWaves Posted November 13, 2022 Share Posted November 13, 2022 Is that ***Best Guess Precip Type*** = SNOW your input? Link to comment Share on other sites More sharing options...
Hoosier Posted November 13, 2022 Author Share Posted November 13, 2022 That's just what the model is spitting out. 1 Link to comment Share on other sites More sharing options...
A-L-E-K Posted November 14, 2022 Share Posted November 14, 2022 On 11/12/2022 at 11:24 AM, A-L-E-K said: Would be lightly hyped if cold, but since warm and winds off lake going dab Nice to see euro still the premier fantasy snow model looking $ 1 Link to comment Share on other sites More sharing options...
Hoosier Posted November 14, 2022 Author Share Posted November 14, 2022 Models really picking up on the lake enhancement, and of course the HRRR is its usual happy self in that regard. Link to comment Share on other sites More sharing options...
Chicago Storm Posted November 14, 2022 Share Posted November 14, 2022 Models really picking up on the lake enhancement, and of course the HRRR is its usual happy self in that regard.Easy toss.There was hope that the elevation correction earlier this year would fix the overzealous LE output, but clearly it didn’t.. 1 Link to comment Share on other sites More sharing options...
Hoosier Posted November 14, 2022 Author Share Posted November 14, 2022 14 minutes ago, Chicago Storm said: Easy toss. There was hope that the elevation correction earlier this year would fix the overzealous LE output, but clearly it didn’t. . That being said, I'd be pretty surprised if the highest amounts in the area aren't somewhere in a zone inland from Lake Michigan. Link to comment Share on other sites More sharing options...
Hoosier Posted November 14, 2022 Author Share Posted November 14, 2022 Tough call here. There's a scenario where if the lake cooperates that I could envision about 3-4", but that's probably near best case. More likely to be less than that, but whatever falls probably won't actually be what's on the ground because of melting in between. Link to comment Share on other sites More sharing options...
madwx Posted November 14, 2022 Share Posted November 14, 2022 for these low rate, long duration events it's a good reminder to use the snow depth output on the models instead of snow accumulation. That will be much more representative of what you'll actually see on the ground Link to comment Share on other sites More sharing options...
Chicago Storm Posted November 14, 2022 Share Posted November 14, 2022 2 hours ago, Hoosier said: That being said, I'd be pretty surprised if the highest amounts in the area aren't somewhere in a zone inland from Lake Michigan. In the LOT CWA (Even the MKX CWA)? Yea, I'd agree. Link to comment Share on other sites More sharing options...
Chicago Storm Posted November 14, 2022 Share Posted November 14, 2022 LOT AFD for @Hoosier... "IN FACT, LAKE TEMPERATURES OF +10 TO +11C AND 850MB TEMPERATURES OF -6 TO -7C AS WELL AS INVERSION HEIGHTS PUSHING 11,000-12,000 FEET WILL GENERATE AS MUCH AS 250-350 J/KG OF LAKE-INDUCED CAPE FROM LATE TUESDAY AFTERNOON THROUGH EARLY WEDNESDAY MORNING, LEADING TO CONCERN THAT LAKE ENHANCEMENT TO SNOW MAY "OVERACHIEVE" IN SPITE OF MARGINAL SURFACE TEMPERATURES. INTERESTINGLY, THE 12Z HREF SHOWS SPLOTCHY 20-30% PROBABILITIES OF SNOW RATES >1"/HR BETWEEN 2-3 PM TUESDAY AND 3-4 AM WEDNESDAY ACROSS THE NORTHERN CHICAGO SUBURBS. PERHAPS MORE CONCERNING IS THE 12Z HREF 24-HOUR LOCAL PROBABILITY-MATCHED MEAN QPF OF 0.75-1.00" ACROSS LAKE, COOK, AND NORTHEASTERN DUPAGE COUNTIES. WHEN APPLYING A STANDARD 10:1 SNOW RATIO, IT'S EASY TO SEE HOW SNOW TOTALS MAY GET OUT OF HAND. HOWEVER, WITHOUT A PERSISTENT BAND HITTING THE SAME AREA FOR HOURS AND HOURS, IT MAY BE TOUGH TO TRULY REALIZE THE SNOWFALL AMOUNTS ADVERTISED BY INDIVIDUAL HIGH RESOLUTION CAMS THAT INFORM THE HREF. FOR NOW, WE WILL CAUTIOUSLY ADVERTISE AN ADDITIONAL 2-3 INCHES OF SNOW ON TOP OF WHAT FALLS IN THE MORNING KEEPING IN MIND OUR FORECAST MAY BE WAY TOO LOW." Link to comment Share on other sites More sharing options...
Hoosier Posted November 14, 2022 Author Share Posted November 14, 2022 Come on LOT, go with the HRRR. It sounds like you wanted to. 1 Link to comment Share on other sites More sharing options...
Hoosier Posted November 14, 2022 Author Share Posted November 14, 2022 16 minutes ago, Chicago Storm said: In the LOT CWA (Even the MKX CWA)? Yea, I'd agree. Yeah I was talking LOT cwa. Link to comment Share on other sites More sharing options...
Malacka11 Posted November 14, 2022 Share Posted November 14, 2022 Seasonal trend moment 1 Link to comment Share on other sites More sharing options...
Chicago Storm Posted November 14, 2022 Share Posted November 14, 2022 3 minutes ago, Hoosier said: Come on LOT, go with the HRRR. It sounds like you wanted to. They went 2-5" in the WWA, so they are pretty close to it. I guess it's time to pull up BUFKIT and check it out. Link to comment Share on other sites More sharing options...
Hoosier Posted November 14, 2022 Author Share Posted November 14, 2022 18z HRRR I guess the question for the downtown Chicago area is whether there will be a window where the convergence axis starts to shift eastward and flip winds offshore while still having some precip around. That is sort of being hinted at on Wednesday and may represent a little better opportunity for the core of the city, but overall the better place to be is inland. Link to comment Share on other sites More sharing options...
A-L-E-K Posted November 14, 2022 Share Posted November 14, 2022 Office buried, dab at home, almost perfect for early season 1 Link to comment Share on other sites More sharing options...
Chicago Storm Posted November 14, 2022 Share Posted November 14, 2022 1 minute ago, A-L-E-K said: Office buried, dab at home, almost perfect for early season You're still out here by ORD? 1 Link to comment Share on other sites More sharing options...
hardypalmguy Posted November 14, 2022 Share Posted November 14, 2022 Never bank on warm lake temps keeping it all rain. Remember in October 1989, MKE got over 6" of lake effect snow. Same thing happened in November sometime in the 90s. Link to comment Share on other sites More sharing options...
Hoosier Posted November 14, 2022 Author Share Posted November 14, 2022 10 minutes ago, hardypalmguy said: Never bank on warm lake temps keeping it all rain. Remember in October 1989, MKE got over 6" of lake effect snow. Same thing happened in November sometime in the 90s. It's part science and part art when it comes to figuring out how much/how far inland for the marine influence. Warm lake = rain can definitely be overly simplistic. There are all kinds of factors that go into it, such as how cold the airmass is, lake water temps, exact wind direction, wind speed, precip rates. If we had 850 mb temps of -15C tomorrow, then Alek would be ripping snow with significant accumulations lakeside despite onshore flow and water temps of 50+. But we don't have that so it's a more nuanced picture as you move from lakeside to farther inland. Link to comment Share on other sites More sharing options...
A-L-E-K Posted November 14, 2022 Share Posted November 14, 2022 41 minutes ago, Chicago Storm said: You're still out here by ORD? Yup Link to comment Share on other sites More sharing options...
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