Track the rain here before you head out

Joe’s Wx Blog: May snowstorm continues

This is an archived article and the information in the article may be outdated. Please look at the time stamp on the story to see when it was last updated.

I wanted to give you a late evening update and also to remind you to follow along with us on Twitter (fox4wx) for additional late-breaking weather information. Snowfall amounts have tallied from a dusting to close to 2″ on the grassy surfaces. Roads are still hanging on but may start to deteriorate over the next several hours so use caution.

Here is my updated timeline for you.

Tonight: The surface temperatures will be critical because above the surface it will be plenty cold for snow. The rate of snowfall will also go a long way in determining accumulations as the precip switches over later this evening before midnight. IF everything comes together potentially 1-5″ may accumulate on the grass with some slushy 1-2+” amounts on the roads possible before 9AM Friday. Heaviest snows may fall between 9PM and 9AM Friday. In other words, this snow may set a MO record for the heaviest snow over in MAY. On the KS side the May record is 8″ in Tribune…that looks safe. Most of the accumulations will be from now through about 7AM Friday then it should lighten up and/or start to transition back to liquid. There will be a VERY sharp cutoff to the snow due to temperatures to the west and north of the KC metro. The axis of heaviest snow may be near I-35 (or thereabouts) and points eastwards onto the MO side.

Friday: Snow tapers before noon and tomorrow is an off and on showery day. Temperatures in the 30s again with perhaps occasional flakes mixed in during the afternoon but no additional accumulations.

We’ve already set a record today for the coldest high temperature ever in May (41°) also and obviously the coldest high on 5/2 (41°) and also a record snow on 5/2 of at least 1/2″ @ KCI through 7PM. Just amazing and again all very historical for KC.

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There is some sleet with a few snowflakes mixing in from the west to the east this afternoon as the atmosphere continues to cool off. The model data this morning continues to be very bullish with the snowfall in the region and while we won’t to the the extremes it’s obvious that a potentially historic and once in a lifetime event may be shaping up, especially later tonight through tomorrow AM.

The main cause of the potential accumulating snow is going to be the evolution of an upper level low that will be developing essentially near KC then consolidating later tomorrow across the MO/AR border. Major props to the GFS for it’s portrayal of this evolution. It then will wobble around for a couple of days.Here is a look a the NAM portrayal of what will evolve over the next few days…you can really see the storm cranking up to the south of KC. IF this would be the winter season and the air/ground would be even colder…we’d be talking at least 8-12″ of snow probably.

The main snow emphasis for us, even though there may be snow into tomorrow will be the potential for accumulations to the snow. My feeling still is that this will be more of an issue later tonight into 9AM tomorrow…as opposed to during the day tomorrow when temperatures should be closer to 35-38°. We’ll get a map posted later this afternoon, but certainly the potential is there for 1-4″ (updated) with some areas doing more possibly, especially on the grassy surfaces.

It’s still though as I mentioned earlier, tricky because we’re going to have to count on the rate of snowfall (the heaviness of the snow) to counter the warmer ground and the still not ideal air temperatures of 32-35° for most of the accumulating snow event. That’s where the development of the upper low is so important and also where the potential of convection/thundersnow play into things.

In some ways this could be a 2-pronged storm because as we head into tomorrow night the precip may again increase, but by then the atmosphere above us won’t be conducive for snowflakes to make it to the ground. You can see that using this data, again off the NAM model. This shows where the model thinks there will be rain/snow.

In case you’ve forgotten, 12Z is 7AM, 18Z is 1PM, 00Z is 7PM and 06Z is 1AM…notice we may be fighting flakes through a good part of Friday, but my thoughts now are that the accumulation aspect of this will diminish before lunch.

We’ll get some additional maps posted in a little while…now back to the AM blog.

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Well in the world of bizarro weather what can I say. It’s difficult 1) to forecast the weather to begin with when things are changing. think about it for a second. Often, through a combination of experience and model advances we try to forecast things that don’t exist. Now, to add to that daily struggle at times, we may have to forecast something that has never happened before in this area. That complicates things even more. You’ll also notice to the right that I’ve changed the “featured” graphic and dropped the severe weather chances for the KC metro to the snowfall potential graphic for the metro. In this case I’m going to start things at a “7” and adjust today as we figure out what to do with the band of rain/snow to the west.

There has already been accumulations to the snow in NW MO in Atchison County. So right there let’s drop the snow myth about accumulations after it’s been so warm into the month of May. Bottom line is IF it comes down hard enough, especially at night, it will stick, regardless of what month you’re in. I’ve been preaching that for days here on the blog as you know.

Next, depending on how this plays out, and as Mike mentioned last night, there is actually a chance of thunder mixing in with the snow tonight. Every major snow this year has had this phenomena and we may try again tonight as the upper level storm starts to develop very close or just to the west of the KC area. Really it needs to be just west of here so that the air aloft is spreading out, allowing the air below to rush in and replace it, creating upwards motions to the air currents and instability.

As far as timing everything goes, we’ll be fine for the rest of the day with rain spreading from KC eastwards through the late AM hours, then more rain in the PM. Tonight though is the time that a transition could occur. More on the timeline at the end of the blog.

The colder air has spread through the region and the precipitation is set up in a band to the west of the I-35 corridor at the time of this writing. Here is the map showing the areas of precip, with the blue shading representing the snow and the green the reports of rain.

sfc

Seems like the snow starts to fall when the temperature is in the 35° range, give or take a degree. Right now, as illustrated by the RED numbers we’re in the upper 30s and temperatures may slowly edge down today but it will be a gradual process.

The key tonight for the region is just how cold the surface temps get. As we’ve seen in the previous snowstorms here this past winter…we really need the surface temperatures to get into the 31-33° range for accumulations to begin. Tonight the temperatures may stay just above that. Even this past winter, it could really be snowing and we still struggled for accumulations. Now comes the tougher aspect of this thing. The snowfall rates which could trump the surface temperatures. Throw in some thunder snow in areas and that should do the trick especially on the grassy areas. Should the thunder snow become heavy enough, even the roads will become slushy, if nothing else.

Concerning the historical context of this storm, I’ll be delving more into this at work this afternoon, but we’ve only had 3 2 snows in May before. The NWS page shows a 4th on the 11th of May, but I checked more into that date, and I think that may have been a hail report back in 2005 that got logged as a snow report. I sent out a tweet about that yesterday. The record again for KC in May is 1.7″ set back in 1907. The record for ALL of MO is 4.5″ up in Bethany, MO per the “official” reports @ NCDC (possibly 5″ in Albany per the NWS in Pleasant Hill) This occurred in one day. These records go back to 1907. Per the NWS in Pleasant Hill “this same storm system also dumped 5 inches on Albany, 4.5 inches on Bethany, 4 inches on Kirksville, Unionville, Trenton and Olathe. Atchison Kansas picked up 3 inches with Maryville, Oregon and Brunswick receiving 2 inches.” It will be interesting to see IF our potential accumulating snow occurs over the course of 2 days…tonight and tomorrow. (I’ve updated some of the information above to reflect NWS and my research concerning May snow). So far Omaha, NE (3.1″) has broken their May record and Owatonna, MN (15.5″) has established a state record for May! As a matter of fact there has been so much snow in parts of MN and WI that power outages are now cropping up and increasing. there are numerous areas up there with over 12″ of snow…imagine that, school cancelling because of snow in May! Here are some snow reports from MN, IA and WI.

ScreenHunter_08 May. 02 09.17

Could school closings happen here in our region tomorrow AM?

More updates on the blog later today/tonight!

Joe

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