Hoosier Posted October 30, 2019 Author Share Posted October 30, 2019 00z NAM a tad deeper again so far. 1 Link to comment Share on other sites More sharing options...
Natester Posted October 30, 2019 Share Posted October 30, 2019 2 minutes ago, Hoosier said: 00z NAM a tad deeper again so far. Doesn't dump quite as much snow in eastern Iowa as the 18z run did. Temps go below freezing even earlier according to the 00z NAM 3k. Link to comment Share on other sites More sharing options...
Hoosier Posted October 30, 2019 Author Share Posted October 30, 2019 Impressive to see the models trending snowier toward the lake. Obviously have to take amounts there with a grain of salt but perhaps increases confidence for a period of snow there, except maybe right at the shore. 1 Link to comment Share on other sites More sharing options...
Thundersnow12 Posted October 30, 2019 Share Posted October 30, 2019 5 minutes ago, Hoosier said: 00z NAM a tad deeper again so far. Impressive run Link to comment Share on other sites More sharing options...
ChiTownSnow Posted October 30, 2019 Share Posted October 30, 2019 Just now, Hoosier said: Impressive to see the models trending snowier toward the lake. Obviously have to take amounts there with a grain of salt but perhaps increases confidence for a period of snow there, except maybe right at the shore. I can see adding Dupage county to the advisories for the 1st event Link to comment Share on other sites More sharing options...
Thundersnow12 Posted October 30, 2019 Share Posted October 30, 2019 Just now, Hoosier said: Impressive to see the models trending snowier toward the lake. Obviously have to take amounts there with a grain of salt but perhaps increases confidence for a period of snow there, except maybe right at the shore. GFS and the 18z NAM to extent only model guidance with the weird sfc pattern like wrapping west that in the model creates winds off the lake. GFS has shown it for several runs now. Link to comment Share on other sites More sharing options...
Hoosier Posted October 30, 2019 Author Share Posted October 30, 2019 Area Forecast Discussion National Weather Service Chicago/Romeoville, IL 909 PM CDT Tue Oct 29 2019 .UPDATE... 909 PM CDT Tricky forecast overnight into early Wednesday morning as low amplitude shortwave trough over the southern Plains this evening races northeast toward the lower Great Lakes by midday Wednesday. Some backing and strengthening of the low/mid level flow in advance of this shortwave aided by the thermally indirect circulation in the right entrance region of the strong upper level jet will result in a strengthening frontogenetic circulation. Forecast thermal profiles look to be precariously close to the rain/snow line, which naturally lends itself to some uncertainties with respect to p-type and any potential snow accumulations. However, cross sections through the f-gen circulation show strong omega co-located with negative saturated EPV, an indication of weak stability/potential instability. This, combined with the strong omega, could result in some heavy banded precip. The heavier precip rates would tend to push thermal profiles more toward all wet snow due to dynamic cooling. In addition, forecast soundings look exceptionally favorable for large aggregate snowflakes, which could result in greatly reduced visibilities (wouldn`t be surprised to see some 1/2SM to 1/4SM) in the heavier snow. Models generally agree that 2m wet bulb temps will remain near or just above freezing, which given warm pavement temps will result in melting and snow-to-liquid ratios. However, even with the warm ground and marginal 2m temps, snow falling at moderate to heavy clip will accumulate, likely even on roadways. Latest guidance that has come in this evening would generally tend to support the going forecast, which has an axis of heaviest accumulating snow from LaSalle County northeast toward the western and southern Chicago suburbs. I do have concerns that the fairly light surface winds could mean less lake warming in Chicago and the immediate metro area and could allow for more snow falling even into the city limits. Going to update grids and forecast to hit snow a bit harder in the city and burbs with a bit more accumulation, but certainly possible that snow could be a bigger problem into the metro area than this. Strongly considered expanding the winter wx advisory northeast into the metro area, but still not confident in the switch over to snow in the city and even less confident in impactful accumulations. Any snow should switch over to light rain and drizzle by late morning we lose ice nuclei in the clouds and column warms solidly above freezing. - Izzi && 1 1 Link to comment Share on other sites More sharing options...
Natester Posted October 30, 2019 Share Posted October 30, 2019 00z NAM 3k says blizzard for southeast Wisconsin and extreme northern Illinois. Going to be tons of power outages in areas where trees are caked with cement snow. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted October 30, 2019 Share Posted October 30, 2019 0z Nest looks like the 18z Euro swath placement wise a little less snow but damn. 5-9” axis from initial band alone Link to comment Share on other sites More sharing options...
ChiTownSnow Posted October 30, 2019 Share Posted October 30, 2019 11 minutes ago, Hoosier said: Area Forecast Discussion National Weather Service Chicago/Romeoville, IL 909 PM CDT Tue Oct 29 2019 .UPDATE... 909 PM CDT Tricky forecast overnight into early Wednesday morning as low amplitude shortwave trough over the southern Plains this evening races northeast toward the lower Great Lakes by midday Wednesday. Some backing and strengthening of the low/mid level flow in advance of this shortwave aided by the thermally indirect circulation in the right entrance region of the strong upper level jet will result in a strengthening frontogenetic circulation. Forecast thermal profiles look to be precariously close to the rain/snow line, which naturally lends itself to some uncertainties with respect to p-type and any potential snow accumulations. However, cross sections through the f-gen circulation show strong omega co-located with negative saturated EPV, an indication of weak stability/potential instability. This, combined with the strong omega, could result in some heavy banded precip. The heavier precip rates would tend to push thermal profiles more toward all wet snow due to dynamic cooling. In addition, forecast soundings look exceptionally favorable for large aggregate snowflakes, which could result in greatly reduced visibilities (wouldn`t be surprised to see some 1/2SM to 1/4SM) in the heavier snow. Models generally agree that 2m wet bulb temps will remain near or just above freezing, which given warm pavement temps will result in melting and snow-to-liquid ratios. However, even with the warm ground and marginal 2m temps, snow falling at moderate to heavy clip will accumulate, likely even on roadways. Latest guidance that has come in this evening would generally tend to support the going forecast, which has an axis of heaviest accumulating snow from LaSalle County northeast toward the western and southern Chicago suburbs. I do have concerns that the fairly light surface winds could mean less lake warming in Chicago and the immediate metro area and could allow for more snow falling even into the city limits. Going to update grids and forecast to hit snow a bit harder in the city and burbs with a bit more accumulation, but certainly possible that snow could be a bigger problem into the metro area than this. Strongly considered expanding the winter wx advisory northeast into the metro area, but still not confident in the switch over to snow in the city and even less confident in impactful accumulations. Any snow should switch over to light rain and drizzle by late morning we lose ice nuclei in the clouds and column warms solidly above freezing. - Izzi && Such a tricky call for Izzy and gang. Would hate to be in their shoes right now. 1 Link to comment Share on other sites More sharing options...
Stebo Posted October 30, 2019 Share Posted October 30, 2019 that is one tight FGEN band for tonight, we have seen those yield spectacularly lately in N IL/S WI. Link to comment Share on other sites More sharing options...
Hoosier Posted October 30, 2019 Author Share Posted October 30, 2019 9 minutes ago, ChiTownSnow said: Such a tricky call for Izzy and gang. Would hate to be in their shoes right now. Window for snow in Chicago is definitely early on Wednesday when onshore flow is lightest and dynamic cooling is maxed. It is basically a done deal imo that the parts of the city like Midway are far enough inland to get some accumulation but question is how much and how close to the lake can it get. Good learning experience either way. Link to comment Share on other sites More sharing options...
OHweather Posted October 30, 2019 Share Posted October 30, 2019 I'm at work and have had a fun few hours pulling my hair out over this...I like 2-4" all the way into the W and S suburbs including LOT and JOT (maybe MDW or just west) and even ORD if the precip gets far enough north. I have no idea what the immediate Chicago area will do, gut says white rain but Izzi's point about the weak onshore flow initially is good and banded snow can trump the UHI if you aren't blowing wind off of a 50 degree lake so that could be fun. The flow does turn more onshore quickly so they may start as a sleety mix, go to mostly snow for a time, then go back to mostly rain before it gets too out of hand in Chicago. There's definitely enough slantwise instability for banded moderate to heavy snow probably enough fgen to focus it (omega on the NAM is decent but have definitely seen better). Ratios will suck but 2-4" should be attainable into the W and S Chicago suburbs (I have no clue where the N cutoff is but someone near or just N of DPA/ORD will be disappointed. This should impact the commute where it's mostly or all snow (also if there's any sleet mixing in that would help with road stickage) as a moderate to heavy wet snow will put a thick layer of slush on roads. 1 1 Link to comment Share on other sites More sharing options...
nwohweather Posted October 30, 2019 Share Posted October 30, 2019 that is one tight FGEN band for tonight, we have seen those yield spectacularly lately in N IL/S WI.I believe April 2016 was similar in being a massive FGEN band rolling thru SE MI and NW Ohio. Actually had a business trip rescheduled bc of this mess Link to comment Share on other sites More sharing options...
RogueWaves Posted October 30, 2019 Share Posted October 30, 2019 1 hour ago, Natester said: 00z NAM 3k says blizzard for southeast Wisconsin and extreme northern Illinois. Going to be tons of power outages in areas where trees are caked with cement snow. SPC had a low risk for "near blizzard conditions" for that area showing, even a few days back. Looking more likely as we get closer. Link to comment Share on other sites More sharing options...
RogueWaves Posted October 30, 2019 Share Posted October 30, 2019 Every NAM run yields a little stronger storm in N Huron. Euro's not far behind in this scenario (990mb) Link to comment Share on other sites More sharing options...
Hoosier Posted October 30, 2019 Author Share Posted October 30, 2019 Went outside to see what kind of precip was falling. The answer... it is mostly rain but there is a little sleet mixed in. Link to comment Share on other sites More sharing options...
Hoosier Posted October 30, 2019 Author Share Posted October 30, 2019 Temp has dropped 3 degrees since precip started. Need a few more. Link to comment Share on other sites More sharing options...
cyclone77 Posted October 30, 2019 Share Posted October 30, 2019 Models are still all over the place with amounts for the QCA. Only thing that's clear is tonight's snow misses southeast, and then a nice long-duration snow event starting tomorrow evening. 2-5" would probably be a safe choice. Anything measurable at this point in the season is pretty noteworthy, so it'll be a big win to be sure. 4 Link to comment Share on other sites More sharing options...
ChiTownSnow Posted October 30, 2019 Share Posted October 30, 2019 Snowing at a good clip here. I had to get up and make sure I see the first flakes of the year 2 Link to comment Share on other sites More sharing options...
Hoosier Posted October 30, 2019 Author Share Posted October 30, 2019 Woke up for a radar check... looks impressive. Mostly rain here but I have a light out back and can see some wet flakes mixed in with this heavier burst. Link to comment Share on other sites More sharing options...
Hoosier Posted October 30, 2019 Author Share Posted October 30, 2019 ORD and MDW both light snow. Link to comment Share on other sites More sharing options...
A-L-E-K Posted October 30, 2019 Share Posted October 30, 2019 Just too warm here, all rain as expected Link to comment Share on other sites More sharing options...
Baum Posted October 30, 2019 Share Posted October 30, 2019 Ground is covered. Snowing at a good clip with big flakes. Looks like this morning is the real show around here. LOT hinting that Halloween event is looking a little less intense. Though, forecast for Halloween is still impressive given time of season. Link to comment Share on other sites More sharing options...
A-L-E-K Posted October 30, 2019 Share Posted October 30, 2019 Those nam and euro solutions from last evening are gonna be lol bad imby. At least LOT didn't bite. Shame about the beautiful banding placement tho, just a bit too early in season for this setup. Still hoping for a DAB with the defo but less than confident 3 Link to comment Share on other sites More sharing options...
mimillman Posted October 30, 2019 Share Posted October 30, 2019 3 hours ago, Hoosier said: Woke up for a radar check... looks impressive. Mostly rain here but I have a light out back and can see some wet flakes mixed in with this heavier burst. Similar situation here. Link to comment Share on other sites More sharing options...
Chicago Storm Posted October 30, 2019 Share Posted October 30, 2019 0.9” ORD so far.Breaks record for the date of 0.7” (1923).. 2 1 Link to comment Share on other sites More sharing options...
WestMichigan Posted October 30, 2019 Share Posted October 30, 2019 Rain with an occasional wet flake mixed in west of GRR. Link to comment Share on other sites More sharing options...
A-L-E-K Posted October 30, 2019 Share Posted October 30, 2019 15 minutes ago, Chicago Storm said: 0.9” ORD so far. Breaks record for the date of 0.7” (1923). . Lol euro Link to comment Share on other sites More sharing options...
Chicago Storm Posted October 30, 2019 Share Posted October 30, 2019 Lol euroThey were all overdone.. Link to comment Share on other sites More sharing options...
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