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1/12/07-1/15/06 NOW:OK/KS/MO/IA/IL/IN/MI (Winter Precip)

Jordan Hartley

Im 4 miles E of Andover,KS at work and we got a nice coat of ice this morning. Snow started falling about 45 min ago coming down horizontal because the wind is blowing pretty good wight now. This is going to be a long weekend for us here in KS/OK especially down in OK. Road crews are everywhere scrambling to get as much as they can on the roads before this afternoon. I have to drive 23 miles back home tonight so im hoping that we dont get any hard core ice until tonight. It looks like things are getting started in OK at the moment alot of precip beginning to fall over most of the state.
 
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This system may bring in more ice that I had anticipated. We have been having freezing rain for at least an hour already here in Shawnee, OK. It is forming a nice coating on the cars and trees. By the time this is over, there should be some great photo opportunities. Travel could be a big problem.
ice.jpg
 
Big question: could the "Norman bubble" live on even with a storm of this magnitude and level of hype??

Predictably, it looks like it very well may. We started mixing with sleet about an hour ago and at this point it appears the mix is more PL than ZR. I find it amazing how sleet manages to be the predominant precipitation type in each and every winter storm here no matter what the models or forecasts have shown. This was the case for December 6-7 and February 17-18 last winter, and it certainly cut down on our snow totals significantly with November 29-30 this winter.

Obviously the storm is just getting underway, but my concern is that with the arctic front continuing its relentless march southward (much farther along than even the fastest of models had shown), what mechanism is there to re-warm the lower- and mid-levels that have cooled enough to allow ice pellets already? If the answer is "none" as I suspect it may be, this is probably the worst bust on a winter storm I've yet seen for the OKC metro area in my two years here.
 
The big thing Brett is the low that comes out of the 4 corners region which is going to pick up all the energy it needs off of this artic cold front. I dont think 3 1/2 hrs into this event is enough time to pull the plug. In fact this storm has the potential of putting off quite a show in the next 48 hrs. I just hope the ice doesnt slide a little N lol. Up here we have a really good base for any snow that does fall everything is iced over and now its just a waiting game.
 
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In Edmond, we're at more of an ice pellet / sleet precipitation form (perhaps even some snowflakes mixed in), with the ground starting to turn white in places. The cold air is stronger and faster-moving than the models were forecasting a couple of days ago, and this may actually help ease the ice storm threat across central Oklahoma I think... If the cold air is deeper than was previously forecast (which may be a first-order guess given the faster-than-forecast speed and intensity of the cold air), we may be dealing with more of a sleet event north of I40 and I44, with the freezing rain more dominant across south-central and south-eastern OK (and adjacent portions of northcentral TX). I guess we'll know more after the 18z OUN sounding. A sleet event seems to be significantly "better" than an all-freezing rain event or an all-snow event (since 1-1.5" of liquid equiv would likely yield more than a foot of snow). Sleet tends to be relatively dense (compared to snowflakes, particularly dendrites) so accumulations are less than some snow types, and it certainly gives better traction than a glaze ice event from freezing rain, IMO.

It's rather interesting watching the wall-to-wall coverage of this nascent event on TV right now... KOCO 5, in my experience, tends to break in most often in any inclement weather situation, and today is no exception (they've been on for a while now). I do think they run out of things to say, since I've seen 3-4 minute stories about how to put a blanket on your windshield to mitigate the glaze icing, and some tips on how to properly scrape your windshield... *rolls eyes*. Oh well, I suppose I appreciate their coverage.


The QPF forecasts are still quite impressive, and there is a flooding threat across the ArkLaTex area with a couple bouts of >1.5" "waves" in the next 2 days. When the actual low/trough moves through, we'll see another substantial bout of precipitation (Sat night through Sunday evening), but I still think the biggest freezing rain potential lies along a Waurika to Eufala to Fort Smith line. If the QPF verifies, this could rival the Jan 2002 ice storm that crippled nw OK.
 
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The big thing Brett is the low that comes out of the 4 corners region which is going to pick up all the energy it needs off of this artic cold front. I dont think 3 1/2 hrs into this event is enough time to pull the plug. In fact this storm has the potential of putting off quite a show in the next 48 hrs. I just hope the ice doesnt slide a little N lol. Up here we have a really good base for any snow that does fall everything is iced over and now its just a waiting game.
Don't get me wrong, this remains a major winter storm, but it appears the threat areas for any given hazard are shifting significantly farther south and east than anyone had expected. I agree with what Jeff said above - given how far southward sleet has already become predominant, it seems that the major ice storm idea the local media and NWS has been touting is, well, on thin ice (sorry ;)).

I guess that is the irony of winter storms of this type - you can be right in the middle of the precipitation and cold air, yet still fail to see a significant or damaging event while locations on both sides of you do, because sleet is little more than a nuisance. Obviously it doesn't take a big change in the thermal profile to make the difference between ZR and PL, and I don't fault anyone for raising the warning flags on this system over the past few days, but all the frenzied preparations and raiding of stores for supplies (I went to Wal-Mart here in Norman last night at 12:30 AM and it was not only packed, but looked like a semi-war-zone) will more or less end up being for nothing if this is a "heavy sleet storm" for OKC.

It's the areas farther south and east that have been told to expect nothing but heavy rain for the past few days that really need to watch out - as well as areas well to the north in Kansas, Iowa, etc. who could see heavy snow.

EDIT: The midday TSA AFD seems to agree with this, as they mention McAlester to Bentonville as the core of the icing threat now with predominantly sleet north of I-44. That is a HUGE difference from the thinking just 12 hours ago. It would seem that a lot of new counties need to be put under an Ice Storm Warning over S/SE/EC OK and W AR, while those north and west of I-44 might need to be dropped in favor of a WSW.
 
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We had a pretty steady freezing drizzle earlier this morning in Overland Park/Lenexa KS (KC suburb) and has since switched over to a very light snow. Looks like the depth of the cold air has become less supportive of an ice storm and more likely sleet & snow. Not exactly sure if the low levels will warm enough at any point for the remainder of this prolonged event to support ZR/ZL glazing. I would prefer no ice after seeing the effects of the bad ice storms so far. Oklahoma, SE/EC Kansas, and SW/C Missouri does not look quite as lucky this time around unfortunately :cool:
 
It's mostly sleet now here in SE Norman. The interesting thing is that the freezing line isn't all that far southeast of here, maybe a county, and yet we are still getting sleet, rather than freezing rain. The cold air must be deeper than expected. I wouldn't be surprised to see the precip type switch back and forth between freezing rain and sleet throughout this event though.

Edit:

Well, the 18Z OUN sounding is in, and it looks like a classic freezing rain sounding to me, with a deep (925-700 mb) warm layer, and a 50-75 mb deep subfreezing layer at the surface. I guess the subfreezing layer is just cold enough to push it over to sleet.
 
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As of 5:45pm...have about an inch of snow/sleet on the ground...roads are snow & sleet covered in Overland Park & Lenexa.


4pm Update - Lenexa KS: still snowing lightly w/o much appreciable accumulation. Sleet is mixed in at times. Temp holding around 15 degrees on west side of KC Metro.
Looks like we may have dodged the dreaded ice storm as deep as the cold air appears.

As of 1pm, we've got about 1/2" of snow/sleet accumulated here in Lenexa KS...have just had a period of moderate snow/sleet (S/IP) here in the last 30 mins.
 
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Brett, I see your line of reasoning, but in this type of situation, it is much more prudent for the NWS to er on the side of a major event than underestimate and leave the public stranded. Furthermore, if you take a look at the special 18z OUN sounding, you can clearly see the warm layer above the surface that will be the main cause for the freezing rain (As Dan Dawson stated). I know it's easy for some to sit back and make criticisms of the NWS forecast, but in this case, I totally agree with their strong warnings.
 
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Im in west central IL. It is 18 with 16 dew point. Lots of Freezing rain, with already .3 of ice. Just got posted under ice storm warning and after talking to nws am anticipating winter storm watch to cover for the 4-8 inches of snow expected
 
Brett, I see your line of reasoning, but in this type of situation, it is much more prudent for the NWS to er on the side of a major event than underestimate and leave the public stranded. Furthermore, if you take a look at the special 18z OUN sounding, you can clearly see the warm layer above the surface that will be the main cause for the freezing rain (As Dan Dawson stated). I know it's easy for some to sit back and make criticisms of the NWS forecast, but in this case, I totally agree with their strong warnings.
I probably could have phrased my last post better - I didn't intend any criticism towards the NWS forecasts, I was just commenting on how much the situation has changed in the past 24 hours. Both OUN and TSA correctly decided to pre-empt the models on the timing of the arctic font, and I commend them for that even if reality turned out to be even colder/faster. And, as I already mentioned in my previous post, I realize very subtle and tough-to-forecast changes in the vertical temperature profile can have a profound impact on the precipitation type and resultant impacts... bottom line, no bash of NWS from me.

In any case, it looks like we're still seeing sleet here in Norman during the 4:00 hour. The 18z sounding did look supportive of freezing rain, but given that the magnitude of that thin low-level cold layer is evidently enough to freeze the drops before reaching the surface, I again have to ask what would eliminate that and allow us to switch back to ZR for the second and third waves. The afternoon AFD's out of OUN and TSA both seem to indicate an expectation that the sleet mixture will continue even with the new batches of precip tomorrow and Sunday.

EDIT: I was just looking at the 18z NAM forecast soundings for OUN, and from here on out it only deepens and strengthens the cold in the lowest level of the atmosphere, with 950 mb temperatures as low as -10°C by late tonight and the freezing line moving up from 925 mb to about 900 mb. Clearly there's no chance whatsoever of snow over the next 24 hours with the very deep warm layer aloft, so it looks like a relatively clear-cut sleet situation for Norman and OKC. Small difference in the sounding, massive difference in impacts and potential for damage and travel disruptions - if we continue to see mainly sleet I would go as far as to say the event will be forgettable and insignificant for the immediate metro area - however, this won't be the case for whatever swath to our south ends up with the heavy icing.
 
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I'm sitting here in Western IL with between 0.75" and 1.00" of ice..mainly sleet. Quite a nasty ice storm that blew up here in the last minute...I don't think things were originally forecast to be this bad in our neck of the woods.
 
Pretty amazing to see the STL metro getting a second major ice storm this season. I can't remember a recent winter with this number and magnitude of ice events.
 
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Very intense line of precip moving into the Wichita metro area. Really good band of freezing rain down starting to come together down in SE OK that will track NE. NWS put out a mesoscale discussion on the band of sleet that is moving into my area, NWS said we could pick up .5-1.5 in as it moves through.

Edit* Line is passing through in the form of sleet and its coming down hard. 3-4 CG's in the last 5-7 min. Very fun to watch.
 
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Here in Edmond, OK (N suburb of OKC), we have about 1.25" of accumulated sleet on the ground, very negligible freezing rain / glaze ice. Most of the ice on ground sfcs is likely the result of the warm ground initially melting the falling sleet. Visibility was quite limited at times yesterday, though it's been just fine since last evening.

The latest OUN AFD confirms what I was thinking regarding the "surprise" precipitation form. My best-guess yesterday was that precipitation size distribution may be the primary culprit for the sleet form (over freezing rain). I noticed early yesterday that the majority of the falling precip particles were very small, with the "sleet" looking like frozen drizzle (frozen, not freezing) much of the time. If this is the case, fall speed of the particles would have been slower than expected, thus the residence time in the shallow sub-freezing air would have been longer than usual. The 18z OUN sounding yesterday, otherwise, certainly looked to support freezing rain, with a very warm nose at 850mb, and a freezing layer than was 500-700m deep. I think that if we had larger precip particles, the drops would have spent let time in the sub-freezing air, and we may not have had a "surprise" sleet event (and we would have had the anticipate crippling ice storm). This is partly why I hate winter precipitation forecasting -- the offices correctly anticipated the much faster-than-models-projected speed of the cold front, and the soundings looked to support the freezing rain mode, but (I suspect) cloud and precipitation microphysics had a different idea. This is starting to mix into a DISC thread, so I'll stop here.

Looking at radar, precipitation is increasing west of the OKC area, with it taking much more of a convective form than we saw for most of yesterday, and there's a few "cells" with >50 dBz returns. This MAY signal that larger rain drops are falling, which will likely result in freezing rain instead of sleet for a time. Larger drops have a higher fall speed, so residence time in freezing air is reduced, and the larger drops take longer to freeze anyway. We'll have to wait and see if this continues through the day and through tomorrow, I suppose.
 
Looking at radar, precipitation is increasing west of the OKC area, with it taking much more of a convective form than we saw for most of yesterday, and there's a few "cells" with >50 dBz returns.
Definitely convective...there has been a lot of cloud-to-ground lightning activity in that area for the past 3-4 hours.
 
NOW: 11am

Here at the farm 5 NW of Piedmont, experiencing a wave of heavy sleet, and some small pea sized hail mixed in. Two cg strikes within 5 miles of the house!! current temp 22F. So far been lucky that this has not been the freezing rain event thats been expected in my area.

Rocky&family
 
This is one of the more unusual widespread sleet setups I've seen.... where you have both a tremendous warm layer aloft on the order of +7 to +10C with a very impressive shallow near-surface cold layer beneath it anywhere from -5 to -10C. It's clearly warm enough in the warm layer to completely melt any snow...all the way north to almost central KS and northern MO.

There's two ways to get sleet...the most typical way to get sleet is from partial melting of snowflakes in the warm layer aloft when the maximum warm layer aloft temps are anywhere from +0.5C to +3C. Below this warm layer aloft, not much "cold" energy is required to re-freeze the partially melted snowflakes as sleet or snow grains or whatever you want to call it. Above +3C in the warm layer aloft, completely melting snow, it will take quite a bit more "cold" energy to re-freeze a complete rain drop back to complete solid ice. The standard 50/50 probability PL/FZRA in this situation is a minimum cold layer temperature of roughly -6C. A colder than -6C surface layer, and your probability of completely re-freezing a rain drop (of a typical rain drop size) rapidly increases. This is the situation that has been occuring over a large area from Kansas into Oklahoma -- really interesting. The OUN 00z and 12z soundings for Jan 13th were really, really interesting with maximum warm layer aloft temp of +11C and minimum near-surface cold layer temp of -6 to -8C

This kind of winter sounding is really unusual!
 
A heavy band of sleet is to makes its way into Kansas City within the next hour or so. It is right know slamming Topeka down south to Emporia. I will keep everyone updated as it makes its way through the KC metro area.
 
A couple small thunderstorms are passing through Norman right now. Precipitation type at my apartment is still sleet, and I just missed the heaviest cores to the north and south, but I can hear the thunder. Wheee!
 
Moderate snow already falling across central Iowa and the ground is almost covered where I live. Still expecting a winter storm sunday night for Iowa. How bad is the ice storm in KS/MO? People are saying this is a crippiling ice storm.....
 
Observed varying sleet "diamaters" with current thundersleet in Norman, ranging from very small (<1/32") then increasing to 1/16-1/8". Clearly, the frozen equivalent of small and big rain drops falling into the subfreezing layer.

Would have been nice to have gotten into one of the heavy sleets cores, but not here in SE Norman. Any reports from NW Norman?
 
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