Joe’s Wx Blog: Another winter smackdown!

Posted on: 8:27 am, March 22, 2013, by , updated on: 08:38am, March 23, 2013

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4PM Update: here is our snowfall forecast for you…things obviously will change over the next 24 hours, but it gives you an idea what we’re thinking about at this point…there may be some upside for areas south of KC depending on the thundersnow situation.

3PM Update: I‘m sure it’s just a matter of time before the Watches are upgraded to Warnings Warnings won’t be issued till early tomorrow AM if need be…could be a high end Winter Weather Advisory or a low end Winter Storm warning based on the latest data.

Meanwhile there are no significant changes in the data although there are a couple of wrinkles that will need to be figured out and that won’t happen till tomorrow. The wrinkles are:

1) Track of the storm aloft...there are minor but important discrepancies between the modelling in terms of exactly where the storm will go. This is causing the models to shift the axis of heaviest totals in a range from areas in N MO to areas just south of the Metro…a compromise is probably best at this point which would place the heaviest near the I-70 corridor and perhaps a bit south of there.

2) The amounts of liquid total precipitation that will fall from 6PM tomorrow through 6PM Sunday which would be in the form of snow for the most part. This is the part that does have me a bit nervous for overforecasting the snow potential. The newest EURO has about (or just shy of a 1/2″ liquid which would be about 4-6″ of snow for the KC Metro. The GFS also isn’t too bullish for the liquid equivalent…also forecasting about 1/2″ liquid which again would be about 4-6″ of snow. the NAM model is more bullish on the precip totals…suggesting close to 3/4″ of liquid, which would be a solid 6-8″ and the higher res NAM model is also in the 3/4″ range. the Canadian is also a bit lower with the liquid “equivalent”. So I don’t want to push the forecast too high on the high side…at this point. Areas a little south and SE of the metro may do better for totals.

3) The temperatures at the surface…this too is tricky at this point…snow and 32-35° will melt off a lot…we really need to get those air temps below 32° for it to pile up with consistency. If we’re still talking about temperatures in the 32-35° range after midnight early SUN AM, then the forecast amounts will be too high.

So where does this leave us…

At this point I have the highest confidence in at least 3-6″ for the metro.

I have high confidence in a 4-8″ forecast for the metro as well.

I have OK confidence in a 6-10″ forecast for the metro, which at this point is what we’re going with because of the potential of thunder snows…IF that potential decreases with the data tomorrow, I may lower the forecast a pinch.

Amounts over 12″ on a widespread basis is the forecast I have the least confidence in for the KC metro area based on the available data today.

As you know things can change around here, especially when trying to figure out a storm in late March when the atmosphere still thinks it’s FEB. Updates to the blog will again cover that angle later tonight and again tomorrow. Also as a reminder, follow us on Twitter @Fox4wx for tidbits of information before and after the storm.

Now back to the AM blog…

Winter Storm Watches are in effect for the region, from St Louis through Columbia into KC and westwards through Manhattan as far north as the IA border and down through the Lakes region as another storm takes aim on KC with initially some rain and or rain/snow mix which will eventually turn over to an all snow situation heading into Saturday night. As usual this will be a fluid blog with additional updates during the day/evening so check back in sometime early this afternoon as I analyze the newest data

This will be a heavy wet snow that has a tendency to “dry” out a bit towards the end of the storm and the snow rates may be pretty good over the course of about 6 hours or so later Saturday evening. The forecasted accumulations are somewhat tricky given the initial part of the storm being rain or some combo, and then even after the transition the potential for melting for the first couple of hours. Eventually though the snow rates and the colder overnight tomorrow night will be too much for the melting process and the snow will start accumulating on the grass and on the roads.

The best parallel I can think of for the storm was our 2nd snowstorm we saw this season. That heavy wet snow that was a pain to shovel. Amounts then were close to about 8-10″ or so on average and amounts this time, perhaps not as heavy will still be beefy and indeed may approach 6-10″ in places. While recovery should be decent on Sunday this till be a major storm and travel will not be good during the day on Sunday. This obviously has HUGE implications for March Madness down at Sprint Center. While I really can’t see there being any cancellations to the games, since really the teams are all staying within earshot of the arena, from a fan perspective and a parking perspective this is going to be a very rough commute depending on the timing of the afternoon sessions. Whomever makes those decisions can help things out tremendously by holding off those start times till as late as possible if that is even doable. The timing of the storm is actually ideal for the city to recover quickly on Sunday afternoon while the roads are pretty empty as is usual for a weekend, but it couldn’t be worse for the NCAA’s.

The track of the storm, at this point, is rather ideal and the moisture that the storm will contain looks very healthy as it wraps into the colder air and dumps snow around the state line area.

The storm now is located in the NW part of the country and will drop into the Rockies and will then intensify in a very favorable location across E KS. This means heavy precipitation for the region. Here is the latest NAM model illustrating the precip as it develops and moves into the region. This model should automatically update throughout the day/night as new data is posted into the system.

Here is a look at the 500 mb level, or about 18K feet up showing the storm’s energy across the PAC NW consolidating across the Plains states and then exiting the region. I understand some of this stuff is tough to wrap your mind around, but I think IF you stare at the following maps that you can sort of see the storm forming right in our backyard.

I’m also curious about the potential of some convection (thundersnow) for the event which would add 1-3″ of snow in localized areas especially from KC southwards towards the Lakes. IF that were to happen, 3 events and 3 thundersnows, that would be impressive and while records aren’t kept for those types of things to my knowledge, would have to be a once in a lifetime phenomena I believe…

So let’s go over a timeline of sorts for this event.

For the rest of today: Light snow will continue this AM, accumulations should be minor but there may be about 1″ north of KC closer to the metro although there has also been some freezing mist/drizzle overnight so there are some slick spots out there on sidewalks and untreated surfaces. Precip will taper off in the PM hours. Temps well into the 30s

Tonight: Quiet and chilly with pretty steady temperatures assuming we keep the clouds locked in. Temperatures near 30°

Saturday: Dry for the 1st part of the day then towards the middle of the afternoon some rain and or a rain/snow mix develops. No accumulations with surface temperatures in the upper 30s or so.

Saturday from 6-9PM: Snow starts to fall, initially melting but will overwhelm the “warmer” ground after awhile. Roads should be OK for the early evening.

Saturday from 9PM to Sunday 6AM: Worst part of the storm, north winds of 15-30 MPM will create a lot of blowing snow as well. 2/3rds of the accumulation for the storm will be in this time frame…I expect 4-8″ of snow in this period…also need to watch for the potential of thundersnows as well.

Sunday 6AM-Noon: Snow may taper a bit but there should still be light to moderate snow falling. Another 2-4″ is possible in this time frame. Snow may become more “fluffy” and drier here as well, as the colder air in the atmosphere from the north works into the storm’s circulation.

Sunday Noon to 6PM: Snow should wind down with temperatures in the 30s. My initial thoughts yesterday in my head were 4-8″, and today I think I want to nudge that up to 6-10″ with some upside in localized areas. There could be another swath of heavier snow amounts towards the south of KC down towards the Lakes, in excess of a foot or so.

So let’s review…all winter through February 20th we had 4.9″ of snow.

From February 20th through today we’ve had 20.5″ for a winter total of 25.4″ of snow.

Now let’s see how much more we add to this by the end of the winter.

Oh and for those keeping track, our monthly temperature is now running 5.6° below average for March…and the hits keep coming.

Joe

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