Joe’s Weather Blog: Accumulating snow likely SAT (THU-2/26)

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Good afternoon…plenty of cold sunshine out there today with temperatures approaching 20°. With the wind blowing in the region though the sub-zero wind chills have been replaced by single digit wind chills in the region…so I guess that’s a step in the right direction.

Forecast:

Tonight: Clear and crisp to say the least as temperatures will tank to near 0-+5°. While skies will be clear early…we should see a rapid increase in the higher clouds moving through the region.

Tomorrow: The sun will tend to be filtered by clouds for a good part of the day. Temperatures may struggle a bit with little wind out there and the milky sunshine in the area. Highs should be in the low-mid 20s.

Saturday: March comes in like a lion…as snow should overspread the region during the afternoon and into the evening. There are still issues though concerning where the heaviest snow track will be or even IF there will be a heavier snow track. I’m increasingly confident that we’ll get at least 2-3″ of snow…from there it remains to be seen. I still don’t think this will be a huge snow for us in the big scheme of things…but for this winter it may be our best one yet in terms of coverage and amounts. Temperatures should gradually come into the mid 20s or so in the PM and then stall with the snow falling.

Sunday: Temperatures will continue to warm up to near 30-33°. There are questions though whether or not we get involved with a rain/wintry mix-snow line setting up near the KC area…

Discussion:

Let’s start out the blog today talking about the snow in the deep south part of the country…here is a look at some of the headlines that a few of the papers had concerning the storm from yesterday. Some parts of N AL/MS and 6-12″ of snow.

 

Use the arrow keys on the right and left side of the image gallery to go through the front pages…

Obviously the folks down there don’t handle the winter weather all that well…and on a national scale you can see the extent of the snowcover.

 

Both Tupelo, MS and Birmingham, AL have both had their 2nd highest totals in their weather history.

A very impressive storm for them…

What about us?

So we’ve been blogging since last weekend about the potential weather maker coming over this coming weekend. Things are somewhat more in focus but we continue to have issues with how things are going to unfold.

There are model differences, as there always are…so that is not surprising to me at all. We’re still not really dealing with an identifiable storm so that makes this a bit more tricky as well.

I typically like to try to keep this stuff simple in terms of forecasting accumulations…I try to figure out roughly how much “liquid equivalent” we’re going to see 9typically that involves cutting the model amounts generated) then think about the ratios that will factor in. I think many of you are familiar with the common 10:1 ratio…where 10″ of snow = 1″ of liquid. Typically the average ratio in KC is roughly 12 or 13:1…so that would mean 12 or 13″ of snow to 1″ of liquid.

The thing is at the onset of the snow…assuming it comes during the afternoon on SAT…the atmosphere will be cold enough to allow a higher ratio (or fluffier snow) to fall. Then as the event unfolds through the evening (and maybe even winds down) the ratios will come back down.

Then there is the matter of just how much liquid do we get to covert over to snow? This is where weather enthusiasts need to pay attention to what the models bang out in terms of the easily accessible graphics…many vendors simply do a straight 10:1 adjustment and call it a day. Use those images with caution! More importantly another thing to consider is that those images don’t take into account the temperature profile of the atmosphere. What I mean by that is IF the surface temperature the model shows is 31° it assumes that ALL precip will be snow…those snow total graphics in many cases may not realize the temperature just above the surface could be above freezing melting all the snow that’s falling. So just a word to the wise for all you snow lovers seeing all the colors on various maps…

So we know this isn’t the greatest set-up…that’s a given at thin point. The cold atmosphere is a + for the snow totals…the duration of the snow though is not the greatest.

At this point my thoughts are that we’ll end up with near 1/4″ to 4/10″ of moisture from this by Sunday morning. Doing the conversions…that would equate to about 3-5″ of snow. Since their may be some dry air initially to overcome and since this isn’t a well defined storm…my initial thoughts for amounts are around 2-5″ in the region (as an average). Does that mean somebody could get more than that in some localized area…YES…does it mean some may struggle to get to 2″…YES (N MO I’m looking at you right now concerning that).

For now again let’s just focus on the “liquid equivalent”…here are the various model outputs through 6AM Sunday…look for the line called “total QPF.

Capture

Also notice the drop off in the totals from the night run (6Z) to the morning run (12Z). The GFS is slower with the onset of the snow that’s why it’s “total QPF” is so much lower through 6AM Sunday.

The EURO model cranks out about 4/10″ liquid through SUN AM…while the hi-res NAM is about 1/2 that amount…so you can see why I don’t want to get too carried away with higher totals at this point.

So again…in case you’re confused…right now I’m in a 2-5″ mindset concerning the Saturday through SUN AM snow…I think much higher end forecasts (say over 6″), while not totally out of the question, may be a bit premature.

Now can we add to that on Sunday?

This is where it gets a bit trickier…because the surface temperatures will be creeping upwards to near 32° during the day…which means whatever falls could be some sort of wintry mix or even freezing drizzle/rain. The model data has been suggestive of some sort of band of heavier precip moving through the region on Sunday late AM/early afternoon. The EURO even cranks out another .1-.2″ liquid from this…ver localized and right on top of the I-70 corridor. There is other model support for this as well.

That scenario is more of a “needle in a haystack” though. It could happen…or that band could be 50 miles north or south of KC as well (if it even happens). So at this point I don’t want to add more to the snowfall forecast based on that one potential band setting up on Sunday, especially as temperatures are near 32°.

Monday should be quite then as the main part of this kicks out on Tuesday, assuming it goes to the NW of KC…we’ll see just rain here and potentially some very mild temperatures for one day before another cold plunge hits the area on WED of next week (maybe the last one for awhile?). As a matter of fact, temperatures will be warming up significantly (well into the 40s…maybe even higher) so whatever falls will be rain.

The only way that changes is IF the storm itself takes a totally different track…and goes to the SE of here…then we’ll have something else to talk about…

Have a great day and sty warm tonight and tomorrow.

Joe

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