Hoosier Posted February 5, 2019 Share Posted February 5, 2019 Temps stayed a bit warmer than expected here last night. Should stay mostly cloudy to keep the diurnal rise in check, but given precip onset timing and dews not being terribly low, it's gonna be tough to get ice if we get more than a couple degrees above freezing this afternoon. Link to comment Share on other sites More sharing options...
Chicago Storm Posted February 5, 2019 Share Posted February 5, 2019 A lot of the higher end guidance from last evening has come in warmer and a bit north this morning. One thing that hurts is that the SFC flow becomes more easterly, instead of being more northerly...which will help bring in more modified air. So there is high bust potential today...and at this point I'd say its more likely than not. 1 Link to comment Share on other sites More sharing options...
Toro99 Posted February 5, 2019 Share Posted February 5, 2019 Both the RAP and HRRR showing what looks like a "lake shadow" effect, which would significantly cut into accretion totals for SW Michigan. Man, it has to be tough forecasting icing events. Yesterday, I was surprised that an ice storm warning wasn't issued by KGRR, and now it looks to be a potential non-event for a large portion of the southern counties. 1 Link to comment Share on other sites More sharing options...
Baum Posted February 5, 2019 Share Posted February 5, 2019 what's the GFS up to on the second wave? Looks a tad more interesting even as it holds on to today's icing event... Link to comment Share on other sites More sharing options...
WinterStorm294 Posted February 5, 2019 Share Posted February 5, 2019 12z Euro upped qpf significantly for SEMI. Wouldn't be surprised to see DTX upgrade some areas to a warning. Link to comment Share on other sites More sharing options...
Hoosier Posted February 5, 2019 Share Posted February 5, 2019 2 hours ago, Toro99 said: Both the RAP and HRRR showing what looks like a "lake shadow" effect, which would significantly cut into accretion totals for SW Michigan. Man, it has to be tough forecasting icing events. Yesterday, I was surprised that an ice storm warning wasn't issued by KGRR, and now it looks to be a potential non-event for a large portion of the southern counties. That is like an anti lake shadow. Flow is out of the east in southwest MI so offshore. Link to comment Share on other sites More sharing options...
Hoosier Posted February 5, 2019 Share Posted February 5, 2019 Chicago Storm mentioned the easterly flow not being that beneficial and you can see it here. If that airmass over Iowa traded places with what's currently in Michigan, then different story. 1 Link to comment Share on other sites More sharing options...
Hoosier Posted February 5, 2019 Share Posted February 5, 2019 That being said, temps are generally underperforming so far in southern LOT. That could reverse itself but if it keeps up, then may have a brief period of icing at onset farther south than what the recent guidance has been showing. 1 Link to comment Share on other sites More sharing options...
Hoosier Posted February 5, 2019 Share Posted February 5, 2019 Just saw Ricky's update which addresses the temperature underperformance south and other aspects... Area Forecast Discussion National Weather Service Chicago/Romeoville, IL 1222 PM CST Tue Feb 5 2019 .UPDATE... 1222 PM CST Did not make any changes to the going Ice Storm Warning and Winter Weather Advisory headlines for the freezing rain this evening/tonight, and no changes yet to forecast ice accums. Start time in western CWA looks to be around/after 4pm or so. There are multiple challenges with the forecast that lessen confidence, specifically temperature trends, road temps and response tonight and duration of freezing rain and associated impacts. Mid day temperatures are a mixed bag vs. most of the guidance, with upper 20s to low 30s I-80 and north and even a few pockets of mid 30s where some filtered sun broke through the clouds. One thing is clear, is that due to thicker low stratus in our south, models are far too aggressive in warming those areas (many already had upper 30s by this hour), so did lower daytime temps well south of I-80 accordingly. Tough to say if lower starting point will allow for a slightly longer icing risk, including a brief window in counties currently without a headline, and will assess this for full forecast issuance. For areas farther north, big question is road temps. We only have limited data access, with city of Chicago reporting to us a range of 33-39F for road temps as of mid morning. Early Feb higher sun angle is able to quickly raise road sfc temps, which with some filtered sun over northern IL, this certainly could be the case and something to keep in mind with respect to travel impacts tonight. Suspect that outside of total ice accums that fall, relatively mild road temps in/near downtown Chicago southward and lag time to drop these may *somewhat* mitigate impacts, especially on well treated and heavily traveled roads. In addition, air temps should gradually inch back to and above 32F overnight. For places that never make it to freezing today and mostly in upper 20s to around 30 tonight, this will be less of an issue, so think that interior (W/N/NW) Chicago suburbs out to north central IL would have higher risk of more significant travel impacts. For ice accretions on tree limbs and powerlines, east- northeast winds sustained 10-15 mph with gusts to around 20 mph are not overly strong, but could be enough for sporadic power outages to result. Other big question is how long sleet mixes in/is primary p-type in parts of northern IL into this evening, especially in RFD vicinity. Soundings do indicate enough low-level cold air for refreezing potential until as late as 10-11pm. Longer duration of sleet if/where that occurs would cut into ice accums. Finally, for p-type overall, the possibility of isolated to widely scattered thunderstorms could at least temporarily throw a wrench in and force varied p-types. This would include sleet to even graupel/snow pellets at times. Castro Link to comment Share on other sites More sharing options...
ams30721us Posted February 5, 2019 Share Posted February 5, 2019 5 hours ago, cyclone77 said: And also thundersnow with that blizzard back in Nov. 06z models and latest HRRR runs have scaled back quite a bit of precip for the DVN cwa. May have a tough time getting more than a tenth or two of glazing if those models are correct. Yep, seems the trend continues with the 12z data. I can't complain about less Frz. rain though. Ha! Well any other Winter, maybe! Link to comment Share on other sites More sharing options...
Hoosier Posted February 5, 2019 Share Posted February 5, 2019 Just posting for entertainment value as I know it's not very realistic but was pulling some NAM forecast soundings for my area for this evening and not only were a number of thunderstorm parameters getting tripped, but even some of the severe indices with surface temps just barely above freezing. Link to comment Share on other sites More sharing options...
Moosey2323 Posted February 5, 2019 Share Posted February 5, 2019 18z HRRR showing warning criteria for most of DTX county warning area. 1 1 Link to comment Share on other sites More sharing options...
Hoosier Posted February 5, 2019 Share Posted February 5, 2019 Hoping for some thunder. Guess it wouldn't be completely shocking to get some small hail in stronger cells. 1 Link to comment Share on other sites More sharing options...
Stebo Posted February 5, 2019 Share Posted February 5, 2019 5 minutes ago, Moosey2323 said: 18z HRRR showing warning criteria for most of DTX county warning area. So does the Euro .3" to .5" I would issue an ice storm warning at least from 8 mile north to I69. 1 1 Link to comment Share on other sites More sharing options...
Chicago Storm Posted February 5, 2019 Share Posted February 5, 2019 ARR 35 and JOT 36. This one might be over before it starts for some areas under headlines. Link to comment Share on other sites More sharing options...
Chicago Storm Posted February 5, 2019 Share Posted February 5, 2019 Decent amount of TS in SE. Iowa right now. Link to comment Share on other sites More sharing options...
Hoosier Posted February 5, 2019 Share Posted February 5, 2019 7 minutes ago, Chicago Storm said: ARR 35 and JOT 36. This one might be over before it starts for some areas under headlines. Meanwhile the area south of I-80 is still running cooler, especially on the IL side. 18z NAM is 1-3 degrees or so too high in those areas on a 2 hr prog. Looks like somebody took a torch to Valpo. Link to comment Share on other sites More sharing options...
Harry Perry Posted February 5, 2019 Share Posted February 5, 2019 Boy... 12z HRDPS must’ve had a rough night 4 Link to comment Share on other sites More sharing options...
Moosey2323 Posted February 5, 2019 Share Posted February 5, 2019 DTX AFD gives no mention of an upgrade to warning. Pretty odd considering most models show above warning criteria ice accumulation. I guess they may be worried about a bust? But for Southeast Michigan this freezing rain will come right before the Wednesday morning commute which makes me think a warning would have been the right call. Link to comment Share on other sites More sharing options...
HillsdaleMIWeather Posted February 5, 2019 Share Posted February 5, 2019 Super tough forecast for my county lol Link to comment Share on other sites More sharing options...
michsnowfreak Posted February 5, 2019 Share Posted February 5, 2019 2 minutes ago, Moosey2323 said: DTX AFD gives no mention of an upgrade to warning. Pretty odd considering most models show above warning criteria ice accumulation. I guess they may be worried about a bust? But for Southeast Michigan this freezing rain will come right before the Wednesday morning commute which makes me think a warning would have been the right call. Remember that ice accretion and qpf arent the same. Still tomorrow morning should be interesting. After not having an ice storm in years (light glazes notwithstanding) we had one April 15th and then possibly tonight. Link to comment Share on other sites More sharing options...
Baum Posted February 5, 2019 Share Posted February 5, 2019 I see LOT ain't backing down despite the trends, Tricky forecast to be sure. Probably best to side with the worst result when it comes to ice. Link to comment Share on other sites More sharing options...
Harry Perry Posted February 5, 2019 Share Posted February 5, 2019 GRR holds off on a warning as well while mentioning much more significant qpf amounts and possible accums reaching .75”.. their reasoning is due to major uncertainties on where the most precip will fall as well as limited wind thus impacts shouldn’t be too bad - plus with the surface temp rising tomorrow morning the ice will melt rather quickly. My take on it is simple - there will be impacts during the Wednesday morning commute and the possibility of a third of an inch of ice. Regardless of the wind - there will be power outages, accidents and in some cases major disruptions in commerce. Link to comment Share on other sites More sharing options...
Hoosier Posted February 5, 2019 Share Posted February 5, 2019 5 minutes ago, Baum said: I see LOT ain't backing down despite the trends, Tricky forecast to be sure. Probably best to side with the worst result when it comes to ice. In a way they are fortunate it is an evening/overnight thing. If you're going to bust you'd rather bust at night. Link to comment Share on other sites More sharing options...
Chicago Storm Posted February 5, 2019 Share Posted February 5, 2019 8 minutes ago, Baum said: I see LOT ain't backing down despite the trends, Tricky forecast to be sure. Probably best to side with the worst result when it comes to ice. There's no way they would downgrade at this point...but it's pretty clear a significant ice threat is not happening in the metro, or even the suburbs at this point. I-39 area on towards the QC has the best chance for highest amounts. Link to comment Share on other sites More sharing options...
Hoosier Posted February 5, 2019 Share Posted February 5, 2019 2 minutes ago, Chicago Storm said: There's no way they would downgrade at this point...but it's pretty clear a significant ice threat is not happening in the metro, or even the suburbs at this point. I-39 area on towards the QC has the best chance for highest amounts. I disagree about the burbs, but then again it may be the terminology about what is the suburbs and significant. Link to comment Share on other sites More sharing options...
Chicago Storm Posted February 5, 2019 Share Posted February 5, 2019 3 minutes ago, Hoosier said: I disagree about the burbs, but then again it may be the terminology about what is the suburbs and significant. Suburbs to me go out to DKB-Morris-IKK. Those areas on in to the main metro are out of the equation for decent icing. Link to comment Share on other sites More sharing options...
Stebo Posted February 5, 2019 Share Posted February 5, 2019 2 minutes ago, Hoosier said: I disagree about the burbs, but then again it may be the terminology about what is the suburbs and significant. I'll say the northern and western burbs at least get .1", enough to cover the advisory, especially the northern burbs. Link to comment Share on other sites More sharing options...
mississaugasnow Posted February 5, 2019 Share Posted February 5, 2019 Getting a bit nervous that London-Niagara is about to see a legitimate ice storm with totals approaching 3/4" of ice. Temperatures are expected to be around 26-30F for all of tomorrow, Toronto is also supposed to get 1-2" of sleet. Link to comment Share on other sites More sharing options...
Hoosier Posted February 5, 2019 Share Posted February 5, 2019 9 minutes ago, Chicago Storm said: Suburbs to me go out to DKB-Morris-IKK. Those areas on in to the main metro are out of the equation for decent icing. I'm gonna disagree with some of that. I think Dekalb over to Aurora and northwest Cook county get a several hour period of freezing rain. I'm less confident on how efficient accretion will be given the expected temps and rates but I'd think a tenth or two at minimum. 1 Link to comment Share on other sites More sharing options...
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