Hoosier Posted January 21 Share Posted January 21 2 minutes ago, Central Illinois said: I wouldn't be surprised if we see ice storm warnings issued N of I-70 in MO/IL if model trends continue... ILX is only forecasting around a tenth of an inch, so certainly some bust potential. Link to comment Share on other sites More sharing options...
Moderators Central Illinois Posted January 21 Moderators Share Posted January 21 1 minute ago, Hoosier said: ILX is only forecasting around a tenth of an inch, so certainly some bust potential. Ya it should be interesting. Its been along time since we've had a widespread icing event in the GL/OV region 1 Link to comment Share on other sites More sharing options...
Icewoz Posted January 21 Share Posted January 21 Conditions have to be so incredibly perfect for a large scale icing event. We can’t even get conditions good enough for a descent snowstorm let alone an icing event in SEMI. 1 Link to comment Share on other sites More sharing options...
Jpfalcon Posted January 21 Author Share Posted January 21 DTX Link to comment Share on other sites More sharing options...
Hoosier Posted January 21 Share Posted January 21 Caveat that this is not the FRAM map, but 18z GFS raised ice amounts most notably around northern IL/IN. Link to comment Share on other sites More sharing options...
Hoosier Posted January 21 Share Posted January 21 Will be curious to see what kind of ice that downtown Chicago can pull off. Obviously have 2 big factors to always consider there, one being the urban heat island effect and the other being lake temps if wind is onshore. In this case, the wind is largely offshore, which will tend to negate the lake impact (nearshore water temps have cooled a fair amount recently anyway). So that leaves the heat island question. That area did get a decent icing event a few years back, so it can happen when the setup is right. 1 Link to comment Share on other sites More sharing options...
MesoscaleBanding Posted January 21 Share Posted January 21 Excellent write-up from ILN Spoiler As we progress later into late Monday evening and after midnight, both the lift and LL moisture will gradually increase from W to E across the region, eventually becoming sufficient enough to allow for /some/ pcpn to work its way into EC IN and WC OH (as well as much of central/nrn IN and NW OH). As this occurs, near-sfc temps should be in the lower 30s, with quite a bit of dry air in the lowest several thousand feet to overcome. Sufficient saturation will occur initially above the LL dry layer, with substantial WAA underway aloft at this juncture. The elevated warm layer looks to be deep/warm enough to promote mainly liquid through it (although suppose that brief IP cannot be completely ruled out, especially near the onset of pcpn making it to the ground). Wet bulbing should occur in the lowest several thousand feet, bringing the air temp at the sfc perhaps even a few degrees cooler near/shortly after the onset of pcpn, despite subtle WAA even at the sfc. The end result of all of this is a favorable setup for freezing rain to overspread NW parts of the ILN FA, mainly after midnight, as the better lift and moisture profile develop into the local area. The other aspect of this setup to consider is that even if the subtle near-sfc WAA is able to eventually overcome the initial cooling effect of wet bulbing and sfc air temps are able to rise to 33F or 34F, the antecedent ground temps are going to lag, potentially by several hours. Ground temps are expected to be mostly subfreezing late Monday night into Tuesday morning, so in the absence of any stronger WAA (which seems unlikely), air temps only a few degrees above freezing does /not/ mean that icing issues won`t develop and/or persist. Given that the pcpn coverage and intensity should be its greatest near/NW of I-71 around daybreak Tuesday, do think that this is the primary time period (~08z-14z) where ice accumulation is most likely to be a concern. This very well could be a situation where sfc air temps are a few degrees *above* freezing and untreated road and ground temps remain at or below freezing for several hours longer. So with this in mind, for the official fcst, allowed for FZRA to exist as a possibility through 12z, even with air temps up to 34F. This will promote the greatest ice accumulation *on the ground* opposed to trees/elevated surfaces and overpasses, as it typically the case in these borderline thermal situations. The main concern would be for rain to freeze on-contact with the subfreezing ground and untreated roads Tuesday morning, creating issues for the Tuesday AM commute, especially in EC IN and WC OH and parts of the Miami Valley. Right now, short-term hi-res ensemble probabilities point to the best potential for greater than 0.01" ice accumulation near/N of the I-71 corridor, with the best potential for greater than 0.05" ice accumulation stretching from EC IN into WC OH, through Tuesday daybreak. As we progress later into Tuesday morning, the combination of rising air temps and solar radiational heating should result in a transition to more "plain" rain, but a brief period of freezing rain even SE of I-71 will be possible after daybreak before this takes place. So... while a winter weather advisory will undoubtedly be needed for at least parts of the ILN FA , do feel at this juncture that we are perhaps just a bit to early to issue with this fcst package. Upstream winter weather advisories that are issued are done so where the confidence is highest in icing issues and freezing rain is expected to begin earlier (perhaps ~12 hours earlier) than will be the case locally. But the key message remains the same, regardless of when an advisory is issued. And that message is that freezing rain is likely to develop late Monday night, especially in EC IN and WC OH and the Miami Valley before transitioning to all rain mid/late Tuesday morning. Ice accumulation on the ground is likely in these areas, especially for the Tuesday AM commute, due to antecedent subfreezing ground temps, regardless of air temps at that time. 3 Link to comment Share on other sites More sharing options...
Hoosier Posted January 22 Share Posted January 22 18z Euro definitely trended a bit colder in IL/IN/MI/OH. Link to comment Share on other sites More sharing options...
Hoosier Posted January 22 Share Posted January 22 00z HRRR is going to unload again with respect to the ice. Link to comment Share on other sites More sharing options...
Jpfalcon Posted January 22 Author Share Posted January 22 Decent icing taking place across the Tulsa area this evening. Reports of accidents and pedestrians slipping and falling downtown. Link to comment Share on other sites More sharing options...
Admin BuckeyeGal Posted January 22 Admin Share Posted January 22 25 minutes ago, Hoosier said: 00z HRRR is going to unload again with respect to the ice. Yikes. 2 1 Link to comment Share on other sites More sharing options...
Admin BuckeyeGal Posted January 22 Admin Share Posted January 22 Rap.. Link to comment Share on other sites More sharing options...
Hoosier Posted January 22 Share Posted January 22 9 minutes ago, BuckeyeGal said: Yikes. Meanwhile the 00z NAM is having none of that. Much less icy overall. Link to comment Share on other sites More sharing options...
Admin BuckeyeGal Posted January 22 Admin Share Posted January 22 Just now, Hoosier said: Meanwhile the 00z NAM is having none of that. Much less icy overall. Have not been impressed with NAM this winter. Doesn’t mean it’s wrong this time. I’d rather it isn’t because ice stinks. Link to comment Share on other sites More sharing options...
MesoscaleBanding Posted January 22 Share Posted January 22 Just now, Hoosier said: Meanwhile the 00z NAM is having none of that. Much less icy overall. I'll consider the NAM at 0z tomorrow night. NAM was horrendous with the details of the last storm until the final run before showtime. 1 1 Link to comment Share on other sites More sharing options...
StormfanaticInd Posted January 22 Share Posted January 22 19 minutes ago, BuckeyeGal said: Yikes. Basically an icestorm 😭😭😭😭 1 Link to comment Share on other sites More sharing options...
Hoosier Posted January 22 Share Posted January 22 Ok, I think I figured out what the NAM is doing. It has a much warmer surge of air aloft than other models (especially noticeable around 925 mb). That essentially destroys the low level cold layer much more rapidly, leading to a quicker changeover to plain rain. While one always has to mindful of waa, there's nothing else even close to what the NAM is showing with the magnitude of that 925 mb warm bubble. 2 Link to comment Share on other sites More sharing options...
Hoosier Posted January 22 Share Posted January 22 Look how far you have to go to find dewpoints above freezing. Link to comment Share on other sites More sharing options...
Hoosier Posted January 22 Share Posted January 22 In any case, interesting setup. There's like no organized surface low to speak of and relatively high pressures are maintained throughout the area. So despite this not really being a textbook big ice setup with a cold high funneling in dry east/northeast flow throughout the event, wouldn't be surprised if it overperforms. I wouldn't ride the HRRR/RAP verbatim (especially at this point), but perhaps they're trying to drop a hint. Link to comment Share on other sites More sharing options...
Jpfalcon Posted January 22 Author Share Posted January 22 WTHR out of Indy. Link to comment Share on other sites More sharing options...
Admin BuckeyeGal Posted January 22 Admin Share Posted January 22 Jym Ganahl just showed an in house model that seemed to most resemble the NAM.. saying no big deal in central Ohio. Link to comment Share on other sites More sharing options...
RobB Posted January 22 Share Posted January 22 I'm not too concerned for my back yard with ice as far as driving hazards are concerned. So much darn salt on roads, that alone will help. 2 Link to comment Share on other sites More sharing options...
Columbusbuckeye Posted January 22 Share Posted January 22 1 hour ago, MesoscaleBanding said: I'll consider the NAM at 0z tomorrow night. NAM was horrendous with the details of the last storm until the final run before showtime. This one could be your next source for at least a delay. Once again, the timing lines up pretty well. 1 Link to comment Share on other sites More sharing options...
SNOWBOB11 Posted January 22 Share Posted January 22 Most models have me getting around 4” of snow from this system before the warmer air starts to move in. We’ll see. 2 1 Link to comment Share on other sites More sharing options...
Columbusbuckeye Posted January 22 Share Posted January 22 2 minutes ago, SNOWBOB11 said: Most models have me getting around 4” of snow from this system before the warmer air starts to move in. We’ll see. Sometimes those front end thumps can be fun. It stinks that it won't stay all snow though. 1 Link to comment Share on other sites More sharing options...
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