Joe’s Weather Blog: Nasty Eastern Blizzard + another KC snow chance (WED-1/20)
Good morning…yesterday was quite the mess as it shows what just a pinch, and I mean literally 1 or 2/100’s of an inch of freezing mist/drizzle can do to area roadways. Even the treated roads were susceptible. I wasn’t totally shocked by the onset of the freezing mist…but was surprised at the end effect of the mist/drizzle. Then of course we were watching the snow change over and in the end amounts for KC were typically under 1″. We were warning you that the PM would be bad for the roads…we were right for somewhat the wrong reasons. I really thought the issue would be the snow but instead it was the glaze. I want to explain why we got the freezing drizzle/mist in the discussion part of the blog.
Today: It may be tough to break out of the low cloud cover all day today As a result it will only be in the 20s this afternoon. The winds will remain light (which is part of the problem) not allowing the air to stir itself up. There is actually warmer air above us this morning.
Tonight: Cloudy skies with steady temperatures in the 20s. There may be some light snow developing from KC westwards overnight into Thursday morning.
Thursday: Some light snow is possible. Amounts for KC don’t look particularly heavy but again there may well be road/travel concerns during the day. Amounts should be in the dusting to 2″ range for KC. I can’t rule out another dose of freezing drizzle either at this point.
It was fascinating and so frustrating to watch the evolution of what happened yesterday afternoon. It was also our yearly reminder just how little some glaze takes to create an utter mess on the roads. When we updated the weather blog I mentioned yesterday that there was some freezing drizzle possible but I thought the snow was going to be the main issue. It was, but the snow was more prevalent off towards the NE/E of KC. That was where we thought the more significant snows would be…so that part worked out in the end.
What I wasn’t expecting though was the effects of the 1-2 hour period of freezing mist/drizzle. I thought that the road treatments from Sunday would prevent the mess that developed. I was wrong. Then again we knew the roads would be messy in the PM…so I was right. I was both wrong and right at the same time. Yet I still feel I was wrong because what caused the mess wasn’t accurately detailed I think.
Now about that freezing drizzle/mist. How can that happen? As they say it’s complicated.
IF you remember the blogs leading up to the events of yesterday…there were troubling signs about how much snow KC was actually going to get. One of the things that I detailed and illustrated for you on Monday was the lack of moisture in the mid levels of the atmosphere, This was the main issue yesterday for KC southwards for quite some time in the afternoon. This moisture is the key to getting snowflakes to actually form around 8-12000′ or so. Take away that moisture and snowflakes have a tough time forming…that was the case for awhile yesterday.
So absent that moisture and with a saturated lower part of the atmosphere…there was just enough lift in the lower part of the atmosphere that we started to see a very fine mist/frizzle develop. Essentially the lower part of the atmosphere became so saturated the water vapor in the air condensed into small droplets. These water droplets then hung/fell in and through the air on top of KC. What’s fascinating is that despite the air temperature through the atmospheric column being below freezing…you can still get these “liquid” droplets to form. They don’t freeze till they make contact with an object that is below freezing. In a sense it’s flying through a cloud. You’ve done it before in an airplane…you’re not flying through chunks of ice, you’re flying through super cooled water vapor that then freezes on a planes skin (not good by the way). So in essence, the saturated air yesterday was like us being in the bottom of a cloud. In order for a cloud droplet to become a rain droplet…they have to increase in size by almost a million times.
These water droplets can stay unfrozen until the temperature reaches roughly -40° F. The process overall is more complicated than what I wrote above…it’s called the Bergeron Process. There are also other considerations including freezing nuclei etc…but that’s enough for one morning. It all has to do with cloud formation.
The freezing mist/drizzle event that we had yesterday afternoon is different from a freezing rain scenario. That occurs when there is a layer of warm air (above 32°) in the atmosphere above us. Then the snow that’s falling melts and doesn’t refreeze until it strikes something on the ground that is below freezing. Yesterday we couldn’t even get the snowflakes to form above us for those 1st few hours in the afternoon. As a result we got stuck with a saturated layer of air from the ground up…and what fell and or condensed out froze on contact. Does all this make sense?
OK that’s enough of the weather lesson for the day.
You are going to hear a LOT about an impending blizzard in parts of the eastern US over the weekend. It should be a doozy for some areas. At this point it appears that the Mid-Atlantic states are going to be the target. Some areas may exceed 30″ of snow! There are going to be rain/snow mix questions close to the coastline. Another facet of the storm is the extreme coastal erosion that’s likely especially on the NJ coastline. IN some respects between the storm’s onshore flow, the high tides and the full moon timing, there may be some areas that have bigger water issues from this storm than from Hurricane Sandy or Irene. So a lot is on the table back east. There are still big questions though how far north the snow will get. Also will there be a sleet/rain changeover near the coastline? That could cut a 24″ forecast of snow to 1/2 that, or less, in no time at all.
Interestingly this storm is going to form and come together towards the east of KC. Let’s go up to about 18,000 feet and see the upper air flow. Notice the “U” shape coming through the Plains. That is the soon to be blizzard. The better dip in the “U” is south of here…but there is a little part of this moving along the I-70 corridor tomorrow AM that should create some snow around these parts tomorrow AM.
Then things merge/phase south of the area and turn towards and up the coastline then out to sea.
Here is some of the latest model data…the hi-res NAM model showing about 1/10″ or so of moisture…notice the heavier stuff out west…should be a nice snowstorm west of KC (by 2016 standards at least)
On a broader scale…
So at roughly a 12:1 ratio Thursday…it seems a dusting to 2″ event is the best starting point for KC…out west though…that could turn into a nice 4-8″ snowstorm where you see the blue colors. The snow may rotate through KC and slowly fizzle as it does so. There is some upside IF the wave that moves through our area holds together longer…it did look a bit healthier on this mornings NAM data at least.
So once again it appears another nickle and dime event is on tap for the KC area. Enough for a potential headache tomorrow but not enough for snow lovers to get that excited about. You want excitement…take a look at these NWS forecasts…(very much subject to change). The highest chances of getting AT LEAST 12″ of snow…through 7AM SAT (EST) is bulls-eyed for you…and this is as the storm is just getting started in a way for the NE part of the country.
Another interesting aspect of this storm, as it relates to us…is that it’s going to strip away moisture in the Plains states after it’s passage. That’s important because another storm is going to be moving through the Plains on Monday…aloft it looks rather healthy…but once again as it gets into the Plains, there will be a race for moisture to return northwards from the Gulf region. It may be another case were we get nickle and dimed with something and it comes together farther towards the east of KC.