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OHweather

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Posts posted by OHweather

  1. 7 hours ago, Powerball said:

    @OHweather

    What say you?

    I was on the desk today and one can see where there are advisories now in our CWA. Can add that the reason midnight shift didn't issue more advisories was due to feeling the set-up is fragile (due to temps) and the snow accum forecast uncertain more so than not thinking the forecast would warrant one if it held. Nothing major changed today (the forecast held) so advisories were expanded. Snow was still 24 or so hours out early this morning so midnight shift didn't necessarily need to issue advisories yet. I can see an argument that maybe not issuing just for Lucas (which some may have found misleading) and holding off altogether would've been better, but Toledo was completely boxed in otherwise and they felt confident enough that Lucas was pretty fail safe which is why they did what they did. 

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  2. 1 hour ago, Stebo said:

    I am a bit surprised the models aren't showing enhancement off of Lake Huron as well, this is the type of setup where we should get some.

     

    1 hour ago, Chicago Storm said:


    And on that note, the lake enhancement looks quite marginal in itself.


    .

    683947533_download(56).thumb.png.fa78ce8c20716e177e2032e18abb2eab.png

    To both of these points, soundings off of Lake Michigan do support some marginal lake enhancement...there's a conditionally unstable layer up to about 900mb and while it isn't much (or into the DGZ), it's modeled to be saturated which if accurate would at least contribute some precip production. Since flakes are being made aloft and seeding the lower level lake enhancement, those low clouds will be able to make flakes and add some amount of snow. It won't be a ton, but over the course of several hours maybe is an extra inch or two.

    1513825441_download(57).thumb.png.292697f42a4af86a439eadff5c29d259.png

    Models briefly have a rather similar look off of Lake Huron so there probably will be some enhancement, but it's similarly marginal...and the synoptic precip starts shutting off quicker so the lake enhancement may not last long off of Huron. Since it won't be that intense it may just not be able to add more than an inch? 

  3. 7 hours ago, snowman33 said:

    Isn't snow/blowing snowing and cold wind chills just common winter weather though? You even said it wasn't as significant. Also, don't we have wind chill headlines for this kind of thing? Wouldn't that be easier for the public to understand? Advisory/warning for snow amounts and advisory/warning for wind chills.

    It's water under the bridge at this point. Just felt the need to state my opinion.

    To your point, an argument could be made that there should've been a Wind Chill Warning (along with or perhaps instead of a Winter Storm Warning) since the cold was just as big of a hazard, sure. Unfortunately, it's not entirely consistent when offices issue cold headlines separately from or included in other winter weather headlines (some offices try not to issue both at once, others sometimes issue both at once). I think in that case the Winter Storm Warning was locked in more than a day out when the snow looked somewhat more impressive. In our area we figured about 2" of that snow led to enough blowing snow to necessitate a Winter Storm Warning, though we had prolonged 40-55 MPH wind gusts which may have been a bit stronger than what you had. 

  4. The pre-Christmas storm was absolutely worth Winter Storm Warnings btw...it wasn't much snow (yes, less than expected), but it was blowing around quite a bit for a day and a half with brutal wind chills. There was a prolonged period where travel was hazardous in any kind of open/windy area with dangerous cold causing infrastructure issues. It was a distinctly elevated risk to life and property for those not prepared for the conditions and lasted a solid day and a half. It was worth the warnings even if the impacts weren't as significant as what looked possible a couple days out. 

    For this one, it's the short duration and marginal boundary layer that's the issue. The lift and moisture are good, agree with Stebo there should be some banding on the east/northern flanks, but it just won't last long and won't be extremely efficient so it'll be hard for many to get 6"+. It'll snow hard and be a wet/picturesque snow (though not quite as wet as last Friday's) but the totals will mainly be in the 3-6" range IMO. The area that could *locally* get 6"+ is near the western Lake MI shoreline where some lake enhancement will be in play, especially if banding can pivot over that general area. That'd be enough for a narrow 6"+ lolli just inland from the lake in WI or NE IL. 

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  5. 17 hours ago, NEOH said:

    Can't winter just go away peacefully :lol:. Pretty good consensus but marginal temps are a bit concerning. 

    Going away would imply that it was ever here!

    I actually think this could be a warning-level snowfall for the primary snowbelt (and probably Cleveland metro too) if we see the southern low track advertised by the GFS and Euro, with at least a good few inches of synoptic snow Friday followed by wrap-around and some lake enhancement Friday night. However, the NAM/RGEM/CMC are a little farther north with the low track and bring a dry slot and some rain up to the lake even in northeast OH for a few hours Friday afternoon and would maybe more of a sloppy system with probably more of a casual advisory snow. The blocked pattern over eastern Canada and the north Atlantic at least leaves the door open for the southern track, but the bologna is sliced pretty thinly. Curious to see what today's 12z runs show. Suspect the NAM/RGEM are too amped but could see some sort of a compromise solution in which the GFS/Euro tick somewhat warmer. 

  6. 1 hour ago, RCNYILWX said:

    The CMC was not good, right for the wrong reasons in the Chicago metro. It was too weak and too far south with the surface low, and didn't capture the dynamic cooling that occurred to support the accums of 2-5" of paste in the southeast 1/3 of the CWA. It only gets credit for having the farther south precip swath.

    GFS operational did fairly well and then once the ECMWF adjusted, it did pretty well, not a great performance overall though because it was too far north until pretty late in the game. We only have the UKMET via Pivotal Wx, but it did perform pretty well at a longer lead time.

    NAMs performed the worst of the models we commonly utilize. HRRR and other CAMs did well with capturing the high winds in Central IL and IN.

    This event was also a good case for the algorithm snow maps to be banned. Forecast positive snow depth change was the best option for snow amounts.

     

    Was looking at the HRRR positive depth change, it did pretty well yesterday morning with the max swath (and maybe was just a tad too low on some on the fringes in eastern IL?). I thought the rates/QPF could support12”+ lollis where the band would pivot between N IN/SE MI/S ON (figured when rates were really heavy ratios would come up enough to allow for that kind of accumulation) but it seems like about 11” of concrete was the most anyone could muster. 
     

    19CAB7FE-423A-499D-A3CA-CA36D5684FEE.png.fc8c944b43fe07f2607080945cfdcc3b.png

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  7. 4 minutes ago, Powerball said:

    Kind of disappointed that we haven't got a heavy snow MD from the SPC (yet).

    I've seen them written up for much wimpier events...

    Guessing it's mainly because their focus is on the severe wx in the Ohio/Tennessee Valleys as opposed to not expecting this/not thinking it's worth an MD. 

  8. 3 minutes ago, Chicago Storm said:

    I had been going with gusts up to 60MPH being likely (Didn't want to go all in on the hi-res' higher end depictions alone). But yea, a lot of downstate IL NWS offices were more conservative and only suggesting gusts up to 50MPH, which was quite surprising.

    With it happening widespread in real-time now, any that haven't jumped onboard yet...it's a lost cause.

    I wouldn't have bet money on the 70mph gusts in IL on the north side of the low ahead of time either, but throwing out 50mph and hoping that holds when there was a pretty coherent hi-res signal for at least 60mph (with the HRRR consistently advertising the potential for 70+ exactly where it happened) is pretty blegh given the borderline rapid deepening and very anomalously low MSLP values...that were fairly well-advertised. 

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  9. 6 minutes ago, Chicago Storm said:

    Widespread 60-75MPH post-frontal wind gusts across much of S. IN/KY/TN as well.

    Frankly was miffed (and still am for some areas from NE OH into NW PA/SW NY where wind headlines STILL haven't been hoisted) at how conservative some offices have been with wind headlines on this one, outside of offices south of the Ohio River where warnings went up much earlier. Maybe when we're setting record low pressures it's a good sign to just issue the darn wind headlines. Hi-res models had gusts as high as what's been measured...I get that sometimes they're overdone but it's rare that a <980mb low isn't a giant wind bag.

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  10. 11 minutes ago, Chicago Storm said:

    Getting some very high wind gusts just north of the peak SLP.

    66MPH at DEC and 63MPH at SET.

    An argument could be made for a swath of High Wind Warnings from central IL across central/northern IN into NW Ohio for the next several hours. Hi-res models have been insistent on a broad corridor of 50-60 MPH gusts just N/NE of the low track this afternoon and early evening and the wind will have an easterly component, which with a wet ground which may make it easier to topple trees. Kind of an interesting set-up because it's all driven by the tightening pressure gradient and unusually strong isallobaric flow (blowing towards the rapid pressure falls from the SW) as opposed to mixing down stronger flow aloft...now that we're starting to see some 40-50+ knot measured gusts I think it gives credence to the idea. 

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  11. This is disappointing for Chicago and surrounding areas (while it's still close for the southern suburbs, it will be an extremely sharp western/northwestern cut-off) but for those that cash in, this will be nuts. Seems like it starts getting good somewhere over far eastern IL or northern/western IN. With an outside-of-early-March-climo low pressure tracking through the Ohio Valley ahead of an extremely sharp, negatively tilted shortwave and deepening considerably while ingesting and lifting a very moist and somewhat unstable airmass precip amounts will be impressive.

    hrrr_f6.thumb.png.8b84fd79bf8853ef652f97487933d798.png

    1836978469_NAEFSreturninterval.thumb.png.cd0e52e62731b7f35c6ca42e1f5ab093.png

    The lift is progged to be maximized in the DGZ in the deform band that will peak in intensity from northern IN into southern/eastern lower Michigan, southern Ontario and northern NY this afternoon and evening. While it's too warm to snow now, dynamic cooling will be more than adequate later. 

    1217760460_HRRRsnowsounding.thumb.png.3a2b0dcb18f90739c9be175370cd220c.png

    This sounding supports production of all ice crystal types due to saturation and lift through an incredibly deep layer. However, with very impressive lift maximized in a weakly stable DGZ to go along with a deep 0 to -5C layer in the low-levels dendrite production will reign supreme aloft and large aggregates will result by the time they reach the surface. This kind of heavy snow with large flakes will have no problem cooling surface temps to 32-33F under the heart of the band once it gets going. 

    549961347_ezgif.com-gif-maker(23).thumb.gif.b319dfc6b6278dc71be207ee970e3d22.gif

    Hi-res QPF guidance suggests 3-hourly precip rates of 0.75-1.25" in a narrow zone in the deform band as it peaks in intensity from northern IN and southern/eastern lower MI into southern ON this afternoon and early evening, with peak hourly rates of 0.25-0.50" implied. Snow ratios will probably be ~8:1 under the heart of the band when rates maximize (and will otherwise be less), suggesting hourly snow rates of 2-4" an hour are possible (if not likely) in a narrow zone where the snow band is heaviest. This will be 2-4" per hour of very heavy, wet, substantial snow. Outside of the heaviest band slightly warmer surface temperatures and lighter rates will lead to lower ratios and sharp snowfall gradients. 

    ebfce13d-21fa-4803-9eec-7954206e23e8.thumb.gif.6dfe8984412f0be37ee2637d91c836fa.gif

    While it seems like somewhere from northern/western IN (perhaps starting in far eastern IL) into southern/eastern MI and southern ON/northern NY will all be impacted by this heavy band, there's a consistent signal it will pivot somewhere over northern IN or southern/eastern MI. Where this occurs, 2-4" per hour rates will last a good 4-6 hours and storm totals jackpotting 12"+ (not sure what the max possible amount is given low ratios and marginal surface temps, maybe 16 or 18"?) are likely. Where this band pivots and the higher amounts occur it will be a crippling snowstorm as roads will be nearly impassable by late afternoon/early evening due to rapid accumulations of heavy, wet snow...and due to what will likely be more widespread tree damage and power-outages, given what will be an excessive amount of very sticky snow to go along with wind gusts over 40 MPH at times. My gut feeling is that Detroit proper will get several inches (3-6") of very wet snow with amounts quickly increasing to the west/northwest due to less urban influence and slightly more elevation. 

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  12. This winter has felt worse than 2011-12, and I believe the numbers show that (this winter was definitely a bit warmer, and snow has been at least a bit less across the board, especially in the snowbelt). 11-12 was my prior "low benchmark" in this area. 19-20 was much worse where I was living in NJ (we got about a foot for the winter, average where I was living was probably 40-45"), but their climo baseline is warmer/less snow than here. 

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  13. 9 minutes ago, RCNYILWX said:

    Very good agreement between the 18z EPS and GEFS actually with that shift south of the EPS. But that also means there's still a decent # of members north of the operational, similar to the 18z GFS/GEFS.

    When the 18z Euro did shift south, it was a good reminder to me to not necessarily put too much stock even into a model I tend to trust more, particularly in this type of forecast that is sensitive to relatively small changes in the setup and the mass fields.

    @OHweather, great post btw. Would you put more trust in the ensemble means at this point? Wondering if that may be the way to go since they've been generally more stable than the operational runs.

    Sent from my SM-G998U using Tapatalk
     

    I've been trying to pay the most attention to both the ensemble means, but also looking at the various threshold probabilities (for both QPF/snow), individual members and some of the new percentile stuff on WxBell (WxBell really has some pretty nice stuff for the GEFS, EPS and GEPS) to get a feel for what the "favored" solution is but also for trends on the fringes. The EPS has been disappointing to me with this one as it's tended to be under-dispersive and following the op, but the GEFS actually had a good spread several days out when the op Euro/CMC were well south and I think it's encouraging that the last couple of runs have tightened up the spread a bit (and seem to be converging on a slightly more amped solution than the op). I feel like I'd lean towards the more amped solution, but I have seen northern stream confluence mess with these sub-tropical jet storms before so the less amped solution is still on the table for now. 

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  14. 1 hour ago, RCNYILWX said:

    I can confidently say that part of the problem with the ice storm forecast out there was the new ptype methodology we were forced into this winter. We had imo a much better system in place for several years up until last year.

    Sent from my SM-G998U using Tapatalk
     

    But here I was under the impression that if we just pulled in the WPC QPF and snow ratios and then ran Forecast Builder and pulled in the NBM temps and dews and clicked on a few buttons and ran the unconditional probability of weather type grids that I’d get a perfect snow and ice forecast in 5 minutes. In all seriousness, I think you folks in central region had a better ptype process than we did up through last winter in eastern region…I was training last winter and only touched mixed precip grids a few times, but it was impossible to get what we wanted with the old conditional wx type grids and top down method we were still using, and there were multiple different tools being used to get those grids by offices around us so it was hard to collab. A lot of hand waiving trying to manipulate grids. I feel like the methodology we use now IS somewhat easier to manipulate and get what you want, but I also feel like it’s rare that I don’t feel inclined to do some amount of editing to temp, dew point, and the various PoWT grids to get what I want in any sort of mixed/changing ptype scenario because the PoWT grids frankly aren’t meteorologically reasonable sometimes. Unfortunately, the level of willingness to make those grids edits seems to vary quite a bit from met to met and office to office, and I feel like those who are reluctant to make edits are prone to doing a less thorough analysis than they otherwise would (with a last second colder trend and unusually efficient accretion with decent rates and temps at or above freezing that recent ice storm was just difficult on the southern fringe, though poor starting grids from NBM/FB couldn’t have helped). 

    Before I derail this thread too much more…my impression on this storm is that every model suggests that when the storm reaches maturity and peak intensity that very strong lift in the DGZ in the deform band will yield sufficient rates and large flakes to overcome any BL thermal issues. I’m pretty confident someone gets smoked. However, the big difference is regarding how quickly the storm deepens and reaches peak maturity which heavily impacts where the deform band reaches peak intensity and is best able to overcome any marginal thermals…as one would expect, the slower deepening favors the E/SE solution. 

    I feel like the extremely sharp and rather anomalous subtropical shortwave, coupled jet structure, and high PWATs/low static stability argue for the quicker deepening, though it’s primarily a sub-tropical jet storm with little actual phasing with the polar jet, so both the track and shape of the precip shield on the northern/northwestern side will be quite sensitive to the amount of confluence to the north/northeast of the low. While I don’t think wholesale changes will occur at this range, subtle changes with that confluence could lead to track bumps to almost the last minute. My gut feeling is we don’t see a track any farther south than the GFS or CMC, but the NAM and Euro seemed to have inched a bit less amped so we’re probably narrowing the envelope. 

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  15. 2 minutes ago, sielicki said:

    Clearly these offices are still learning to deal with their collective PTSD from how badly the Dec21 storm was called.

    When you call for warnings a week early and the models leave you hanging at the last minute, normal people are pissed but the weather nerds understand where you were coming from. 


    When you call it during (borderline after) the event, weather nerds will make forum posts laughing at you, and normal people will think that you nailed it.

    Clearly, among the two options, they prefer to be the ridicule of the Ohio valley subforum. Such is life.

    So, I can say with a fairly high degree of confidence that the December storm underperforming had 0 to do with advisories/warnings being conservative on the southern fringe of this one.

    With that said, you are correct that the general public (and decision makers) does not like having their daily lives disrupted for what ends up being a busted forecast/not a major event and we do take that into consideration, meaning if we're issuing a warning product of some sort we want to be fairly sure, and usually won't do it in a "could go either way" situation. I can't comment on the meat and potatoes of the forecast farther west into IN/MI/IL, but in NE OH/NW PA there was a pretty notable colder trend at the last minute leading to more widespread freezing rain and greater amounts of it farther south than expected 24+ hours out. When you combine a last minute colder trend (that forecasts needed to adjust/catch up to) and the fact that good accretion occurred during the day with temperatures at or slightly above freezing (not unheard-of, but understandably tough to forecast) I can see why warnings ended up being very reactive on the southern fringe. If you want a lesson to take away from all of this as a forecaster, a legit cold high and advection of lower dew point air into a freezing rain situation can cause it to surprise on the fringes...a lack thereof can cause underperformance. 

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  16. Ice accretion is fun...definitely an interesting one today with places getting over a quarter inch of accretion with air temps at or slightly above freezing for some or all of the freezing rain.

    Basically, wet bulb temp, wind speed, and precip rate determine how efficiently freezing rain will accrete. Higher precip rates don't accrete as efficiently due to more of it running off before freezing...though on the flip side very light freezing rain or drizzle can accrete at a better than 1:1 ratio to the liquid amount. Otherwise, it's a battle against latent heat release. If air temps are slightly above freezing you can accrete (as many saw today) if the wet bulb temperature is below freezing due to evaporational cooling. However, when the rain freezes it gives off latent heat which warms the surrounding air, so wind is also very important to the equation. Stronger wind whisks away the latest heat given off and can continue advecting in drier air. Strong winds can also increase accretion efficiently due to giving each given rain drop a greater chance at encountering an elevated object (since the drops move more horizontally as they fall when wind is stronger). 

    Typically, it's a battle against the latent heat release and often that battle doesn't last very long if the winds are light and the dew points aren't that low, but in a set-up like this with an actual cold high to the north advecting in a drier airmass it all balanced out fairly well. I'm guessing the efficiency of the ice with temps at or slightly above freezing was not well forecast...we also under-did accretion here in NE Ohio to the point where we had a few power outages east of Cleveland, and much like farther west temperatures had to get firmly above freezing before accretion stopped. 

     

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  17. 23 minutes ago, NEOH said:

    I was surprised by the amount of ice out this way. Everything is still glazed over.  Hoping the mild weather continues at this point. Despite the ice today, it has looked and felt like Spring. 

     

    It definitely was pouring this morning, so that degree or two of colder temperature into Geauga County compared to Summit probably helped you accrete a good bit more. I figured we briefly had about 0.10" on the trees here, but there was enough liquid for more ice where it was a little colder. Unfortunately, it does look like we get some increased blocking in March...we'll see if that results in any snow or just blunts the warm pattern a bit. 

  18. On 1/25/2023 at 8:14 PM, Chinook said:

    I got 4.0 to 4.5" with pretty high density snow, with less than 4.0" snow depth on pavement, for sure. I think Toledo Express Airport has gotten 0.55" of water equivalent, so that could have normally been 5.5" to 6.0" on grass. It does look like 6.0" at Napoleon or Defiance with also over 6" towards Ann Arbor.  I wonder what the COCORAHS spotters will see for their water equivalent of snow for the 2-day period. My area certainly could be 0.55" like Toledo Express Airport.

    Seemed like all of the reports in Lucas Co were between 4-6” (but with no one reporting a full 6.0”). It was relatively impactful for Toledo as it snowed hard with a number of accidents involving semis on the interstates near the city in the early afternoon, but slightly less QPF due to the dry slot and low ratios ate into the expected snow totals a good bit. Just west where rates were more consistently heavy (and it was more like 32-33 degrees) got a goos 6-8”. 

  19. Just a POS, junk system here the last two days. Estimated slightly less than 2” of snow yesterday morning here, but wasn’t home for most of it and it was down to an inch of new slush by the time I got home. Watched it snow half decently and melt on contact all day at the office in Brooklyn Heights…in hindsight, my snow forecast for the LES in the CLE metro was too ambitious since it didn’t stick all day today and because winds backed SW quicker than initially modeled this evening. At home in NE Summit County it did accumulate better than closer to the city of Cleveland and it did come down for a time early this evening…a little over 2” new today. 

  20. 2 hours ago, vpbob21 said:

    Not sure if this underperformed because of lake influence or the heavier rates skipping around us.  Probably a little bit of both.

    Temperatures ran 1-3 degrees warmer than expected across almost all of our area and accumulations suffered quite a bit outside of the higher terrain and some areas closer to US 30 where heavy snow arrived earlier. A coworker near the office in Cuyahoga County had 1.6” of snow on 0.33” liquid which is :yikes:

  21. The hi-res models are really barking that the deformation band that cranks from parts of central and eastern Indiana into northwest Ohio, southeast Ohio, and southern Ontario during the day Wednesday will pack 1-2" per hour rates, with forecast soundings that support heavy snow with large flakes:

    snowfall_001h_prob01_ne.f01700.thumb.png.2cf4713c7a531c4dedec6b586faa8837.png

    530617256_snowfall_001h_prob02_ne.f01700(1).thumb.png.e11c062808f3b1698b03193a1877799b.png

    snowfall_024h_prob_series_ne.f02400.thumb.png.58d5ed66bdc31d1f81b74bda99c7d30b.png

    1782802386_download(35).thumb.png.393768f0f485f4a8999f258eb4d10e16.png

    The hi-res model consistency (and slight ramp up this run) of the deformation band placement and potential for over 6" with it has been relatively impressive, so we'll see if they're sniffing something out.

    It's worth noting that the synoptics behind this are nuts:

    hrrr_f16.thumb.png.627e223f80bf64a85ce9f1b0f10bde11.png

    Strong divergence in the left-exit quadrant of a jet streak ahead of a sharp negatively tilted shortwave, with a zone of strong warm air advection and low to mid-level frontogenesis beneath this to help squeeze out precipitation:

    1550347554_hrrr_f16(1).thumb.png.8bdbb688eeb4386c2879358dccde5007.png

    725459052_HRRRcross.thumb.png.2bd3c3206a790912aa4b42eb9f0bdbdc.png

     

    Temperatures will be at or perhaps slightly above freezing for most of this snow so ratios won't be great, but heavy snow rates with large flakes are likely to occur in any mesoscale banding that develops within the broader deformation zone on Wednesday. 

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