Joe’s Wx Blog: Can it really snow in May?

This is an archived article and the information in the article may be outdated.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’ll get to that potential aspect to the forecast in just a couple of minutes but first for those who didn’t get a chance to read any of the blogs yesterday I wanted to mention that our friend Reed Timmer will be one of the many parts of School Day @ The K coming up on Thursday AM (keeping our fingers crossed about the weather). In addition to talking to the kids he also will be appearing on Wednesday night @ Ameristar Casino at the AMS/NWS (American Meteorological Society/National Weather Association) gathering. This meeting is OPEN to the public (which is you!) and we welcome you. We do need to get an idea of the headcount though for dinner if you choose or whether or not you just want to hear him speak and show some amazing videos. For more information about RSVPing to this event please for to the KC AMS/NWA webpage or send me an email/comment and I’d be happy to get you more information. PLEASE NOTE THAT AS OF MONDAY NIGHT THIS MEETING MAY BE CANCELLED DUE TO WEATHER CONCERNS!!!!!!!!!!!!!!!!!!!!!!!!!

OK with that out of the way…let’s talk weather. I think yesterday qualified as a Top 10 Weather Day for 2013…temperatures in the 70s, dry air, light winds to a little breeze and generally sunny skies. Tough to beat that! Today while warmer will be more breezy and you may start to notice the humidity creeping up this afternoon as the dewpoints start to rise to near 60°. Not too bad but a sign of a change in the weather. The south winds ahead of a very weak boundary will continue to feed some moisture into the region. Also all the moisture in the soil will also help to try to saturate the lower levels of the atmosphere. Here is the latest surface map showing what’s going on.

sfc

Our model data is perhaps to aggressive in generating a LOT of instability later this afternoon as they think dewpoints will be approaching 70°…hence they’re breaking out a LOT of t/storm activity (mainly the NAM model). I think it’s too bullish on the activity and while there may be some scattered strong storms up towards the IA border…that should be the extent of things. It’s something to watch though as that weak convergence line edges closer to the KC area. One of our latest short term models (RAP) says that boundary won’t get close enough to us and in essence will fall apart later today and that looks more believable to me. This gives me more confidence it the lack of activity today/tonight close by.

The more major weather feature is what I’ve blogged about since last week, and that is the potential for an unusual for early May upper level storm to develop near or on top of the KC area. IF it develops on top of us, or even just to the south of here, it would create weather that is virtually unheard of for early May including highs struggling to get about 45° for a few days in a row. That to my knowledge has never happened before in our KC weather history. The potential is there for some record cold high temperatures and while unlikely with record lows in the upper 20s to lower 30s later this week, there is even a chance of a rare record low with this set-up as well.

All this will be happening sometime on Wednesday as a stronger push of cold air moves into the region. Temperatures on Wednesday may peak near 70° for some, perhaps even close to 80° for areas S/SE of KC depending on how things play out before falling sharply at some point (timing still uncertain). MUCH colder air is virtually guaranteed for THU into the weekend and it does appear that the first 3-5 days will be below to well below average for temperatures.

Here’s the thing though. This upper level storm will be bring with it a chunk of cold air, and as it sits and spins on top of the area this cold air will continue to wrap around the storm system. This would certainly guarantee lots of low gray clouds with occasional showers and rain, but aloft the atmosphere would be cold enough to generate flakes of snow. Believe it or not, depending on where this thing set’s up, and a change of 100 miles could make a big difference on this thing, it’s not out of the question that somebody in our viewing area could see some flakes of snow mixed in with the raindrops. Now temperatures would be, at their coldest, near 40° so I’m not expecting accumulations but snow in early May is VERY rare.

we’ve had 4 instances of a trace or more of snow in May, including an incredible 1.7″ of snow on May 3rd of 1907! Can you imagine that? We’ve had traces of snow on the 1st, the 10th and the 11th.

Here is something really neat, I just dug up the weather map from 1907 on the day we had 1.7″ of snow…it appears it was a day that started as rain and then changed to snow. Here is the map. Click on it to make it larger!

ScreenHunter_02 Apr. 29 08.53

It shows the surface pressures in millibars which is a common way for us to show weather maps. Now take a look at what the GFS is forecasting for Thursday AM…the similarities are amazing!

ScreenHunter_03 Apr. 29 08.55

I’m blown away by this! I wish I could find some upper air maps from that time period but I’m not sure where to go. Thanks to @muwxman I did dig up the upper air map that day. It’s not overly similar in the big picture though.

ScreenHunter_04 Apr. 29 09.32

It does have a trof moving through MO Valley area…but it never closed off into a storm aloft looking at the next day’s data.

I did find some interesting history concerning how the developed upper air maps back in the day. Take a look courtesy of NOAA

The early 1900’s

By the end of the 1800’s, meteorographs had developed to a point where they could be carried aloft by free, unmanned balloons. Such soundings reached the stratosphere that was a much greater height than that achieved with manned balloons or kites. After the balloon burst, the meteorograph returned to Earth and preserved the recorded data for days or weeks until it was found. The major drawback to this sounding approach was that the data was not readily available for weather forecasting and was lost if the meteorograph could not be recovered. A means of solving this problem was keeping the balloon captive, but this limited the maximum altitude that could be achieved.

The advent of aircraft carrying meteorographs brought an end to routine kite observations by 1933.  From about 1925 to 1943 the Weather Bureau and Army Air Corps operated a network of up to 30 aircraft stations across the country that collected aircraft observations or “APOBS”. However, like the kite, the aircraft could not be flown in poor weather and the data could not be analyzed until the plane landed. Furthermore, the maximum altitude achieved was only about 5 km.

To supplement the kite and aircraft data, Weather Bureau stations in 1909 began to track small, free balloons (i.e., pilot balloons) with an optical theodolite to obtain winds aloft information. At night a small light was attached to the balloon to aid tracking. Although winds aloft data could be obtained in near real-time, the balloons could only be tracked to about 5 km under good sky conditions. Moreover, when clouds or poor weather were present, sight of the balloon could be lost resulting in little or no data.”

So there you have it a little history and proof that it can snow in early May!

Joe

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