Looking better for the Super Bowl snowstorm?

With the forecast models trending a bit drier, I will officially call Tuesday's event not worth talking about in the blog, especially with a bigger storm potentially affecting us next weekend. We should see around 1" of snow on Tuesday, which at least will cover up most of the ground.

However, it's time to turn our full attention to a big storm that will affect the Eastern U.S. next weekend. The forecast models have flip-flopped around since yesterday...

GFS now shows a primary low pressure system moving through the Ohio Valley before the energy gets transferred to a secondary low pressure that goes out to see. Due to the transfer of energy, the precipitation shield never quite gets up to us.

ECMWF now shows the big low going out to see, but shows a pretty nice clipper system moving through our area. The two storms almost phase (combine together)...if that happened, it would have been a big storm with the main storm going well to the west.

UKMET is well to the south and east.

GGEM (which I don't really have any good images for) shows the storm tracking inland, with the precipitation shield similar to that shown by the GFS.

In summary, the forecast models on average have trended a little to the northwest from this time yesterday, but almost all of them have changed their solution from yesterday. The GFS is well to the north of where it was yesterday, the ECMWF and UKMET well to the south and east. The GGEM has stayed fairly consistent, with the precipitation shield a little to the north of where it was yesterday, but the storm track a little to the south.

In addition, the models have some serious differences in the upper levels of the atmosphere at this timeframe. The GFS never drops down any energy from Canada, which leads me to question the accuracy of its solution at the surface. On the other hand, the ECMWF drops in a nice clipper from Canada, and as I mentioned earlier, it comes thisclose to phasing (combining together) and giving us what would likely be a big snowstorm.

So what does it all mean? At this point, not too much. If anything, it looks better for us today than at this time yesterday, as most of the models have shown the potential for the northern stream energy and the southern stream energy to phase (combine together), and as I mentioned yesterday, phasing means everything in us getting this storm.

In conclusion, the forecast models still have some big differences to get worked out, so it appears to be a wait-and see situation for the next few days. I believe we have five extremely wide ranging scenarios with this storm.

(1) No phasing, with the main storm being supressed well to the south.
(2) A partial phase, with the main storm going up the East coast but some moisture being thrown back towards us, resulting in minor accumulations.
(3) A full phase, which would likely result in our area receiving a notable snow event.
(4) A primary low pressure system tracking through the Ohio Valley, and energy being transferred to a secondary low pressure system which would either track up the East Coast or out to sea.
(5) The main storm goes up the East Coast or out to sea, but we get some decent accumulation with a clipper system that moves through our area.

With all these as possibilities, this is definitely a wait-and-see situation.

That's all for today, I'll have a new post up tomorrow evening.

Light Snow Tuesday, small chance of something bigger for next weekend?

Two things to talk about today. First, we'll start with the midweek system. This is a classic clipper storm that will dive down from Canada and move like a bowling ball through the Midwest. Forecast models lately have been trending wetter with this system. For example, take a look at the latest run of the NAM which paints a swath of heavier precipiation from this storm along the I-80 corridor.

With the previous clipper storm that gave us our largest accumulations of the season (so far), the NAM was the most accurate model. In general this winter, the NAM has been the most accurate model so I'd lend more weight to it than the other models. However, even the GFS has trended wetter with this system, as you can see below.

Both models place the heaviest precipitation just to our south, but considering the general trends with clipper systems this winter, I wouldn't be surprised to see the heaviest precipitation actually end up a little further north than is currently depicted. I'd call for 1-2" with this storm right now. Not much, but considering our last 1"+ snow was 3 weeks ago, it's worth talking about I guess.


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Looming 6-7 days away is a bigger system...the question is, who does it affect? I'm not willing to offer up an predictions 6-7 days out, but I will discuss our chances. First up, let's look at where some of the forecast models have this storm tracking.

The GFS has the storm going off the coast of the Carolinas, out to sea.

The ECMWF has the storm as a huge hit for the east coast.

The UKMET has the storm at the MS/AL border but the model doesn't go beyond that image...extrapolating it out it would probably be a little west of the ECMWF.

An explanation before I get to the next paragraph...a storm "phases" when two systems combine to make a stronger system. A phase generally causes the storm in question to track further west.

Still a wide range of possibilities with this storm. The GFS and ECMWF have some huge differences, but considering what they are showing in the upper levels of the atmosphere, their solutions make sense. The GFS shows the southern stream storm moving through the U.S. without phasing with another system. That's what happened with the current storm that's dumping snow on Richmond and Washington D.C., so if it happened again, it stands to reason that the storm would track well south of us.

On the other hand, the ECMWF shows a partial phase between the southern stream system and an upper-level system in the Plains states. It doesn't fully phase, but it does phase enough to prevent the storm from going out to sea. Still, neither model shows us being affected by the storm in question. So why am I talking about this? Because the models are not that good at depicting upper-air patterns 6-7 days out. The ECMWF seemed to me to be pretty close to a more complete phase between the two systems, and the more the systems phase, the further west it tracks. Therefore, it is not out of the question that this tracks far enough west to affect us. Is it likely to happen? No. Is there enough chance of it happening to make it worth talking about? Yes, especially with the lack of snowstorms so far this winter.

That's all for today, next post will be up by this time tomorrow afternoon.

Small Chance of a Cold Day Tomorrow

Low of 1 degree, wind chills down to -11, the fact that it's a Friday and elementary and middle school have a scheduled day off is + factors for our chances of a cold day.

The huge overriding negative factor is that there is not even a Wind Chill Advisory out on this.

Therefore considering all factors I will say there is a small chance of a cold day tomorrow. As some may remember from last year I don't bother predicting cold days, but I will give tomorrow a "D" grade for our chances of getting a cold day...

Otherwise, the enhanced snowfall potential looks to be pretty much over. The storm I was really liking to hit us went well south and is currently tearing up everywhere from Oklahoma City to Raleigh. Next up is a likely moisture-starved system that will track through early next week and give us some minor accumulations. Beyond that, there are a few storm chances in the extended period but nothing too promising.

Enhanced snowfall potential Jan 28-Feb 6???

After a really, really boring weather period in the few weeks after the January 7th snow event and the January 11th rush hour snow burst, it seems that things are finally going to be picking up in the next 1-2 weeks. First, I'm going to discuss some minor short term events, and then I'm going to discuss why the time period from January 28th - February 6th looks pretty interesting...

First, just for the sake of mentioning it, here's the current radar:

That precipitation shield is going to try and make its way up into SE Michigan tonight, but it's going to have a very rough time overcoming the dry air in place. If by any chance precipitation does fall tonight, it would either be as very light freezing rain or snow. It won't be enough for a snow day tomorrow, but there's a small chance that the roads will be a bit slippery tomorrow morning.

Next, a strong low pressure system is going to pass to our west this weekend. Precipitation type will be rain, with an outside shot at a thunderstorm on Sunday (just think of it as a chance for our snow pack to start fresh again...because all the snow that hasn't been piled up will melt from this system). Anyways, the reason to like this system is that it's going to send a strong cold front through the area on Monday, allowing for much colder air to (finally!) move back into the area and probably stay for a little while. In addition, there could be a minor snow event as this system moves out. Accumulations most likely would not be anything notable, and that's something I'll focus more on over the weekend.

The real timeframe to get excited about is from January 28th - February 6th or so. I usually don't talk about long-range much in this blog, but as there's been nothing much to watch snow-wise in the near-term, I've been looking at the long-term. Considering that it is outside of 7 days, the forecast models have been fairly consistent in showing a cold airmass over our area, and a relatively active storm track. With all this in mind, I decided that the enhanced snowfall potential in this timeframe is worth noting. I'm not willing to get any more specific than saying there's a higher than normal chance for a snow event in this timeframe, considering we're still 1-2 weeks out. But it's definitely something to watch in the upcoming week.

Still not much to speak of...

Still not much to speak of for the next week, storm-wise. At this time yesterday, it appeared that there could be an ice event around midweek, but model runs since then have backed off of that idea.

I would not be surprised if the first storm that comes through around next weekend is a warm storm, but that storm should allow the cold air to move in. Don't give up hope yet, there will be other storm opportunities this winter.

Final Thoughts

All in all I am happy with how my forecast turned out. I had us pegged for 4-6" of snow and said we would have school today...at my house we had 4.5" of snow and unfortunately, we did have school today.

Later tonight I'll post a map of the actual snowfall accumulations with this storm compared to my forecasted accumulations.

The next possible storm is still over a week away, so I anticipate taking a break from posting until Monday Night unless something else pops up.

Still sticking with 4-6" of snow...school?

Alright going to make this rather quick tonight, as we're already halfway into the storm, therefore only nowcasting is necessary.

By my measurements, we have received about 3" of snow since the start of the storm. Snow was heaviest from around 4-6 pm, but has since tapered off quite a bit. Current radar shows the main band of snow just to our north (ignore the hole around Pontiac, that's just a radar problem).

Short range, high resolution forecast models support this band dropping a little more south overnight. Therefore, we should get one more round of snowfall. Depending on the length of this second wave of snowfall, we could get anywhere from 1-3" more of snow. I'd lean towards the additional total falling somewhere right in the middle, around 2" more. To leave a window of accumulation open though, I will continue my forecast of 4-6", but drop us out of the "locally higher amounts" as I feel any reports of over 6" will be extremely isolated.

Anyways, on to the prediction. It's kind of a tough call, but I think we will have school tomorrow. I have 2 reasons for thinking this:

1) Snow day level totals will be extremely isolated. With this storm, I bet we'll see widespread 4" totals, numerous 5" totals, but only isolated 6"+ totals. Based on this, I see all the schools that have 4-5" of snow call for no snow day, and then that causes the schools that have 6" of snow to also call for no snow day, because no administrator likes to be the one of the only schools that doesn't close.

2) Roads are bad now, but with snow coming to an end by 4:00 a.m., the road crews will be able to catch up with making the roads serviceable for tomorrow morning.

The bottom line is that a snow day could happen, but I just can't see a good enough chance of it happening to predict it.

Snow Map:

Upgrade: 4-6" of Snow With Locally Higher Amounts

A good consensus has formed between all of the forecast models with regards to the position, timing, and strength of our upper level low. I have a relatively high confidence in my accumulation forecast, as only nowcasting features need to be worked out with the storm. These features will determine which areas will receive the "locally higher amounts".

Anyways, the last remaining forecast model with a southern track, the GFS, jumped into agreement with the rest of the models with this morning's run. I therefore have a good deal of confidence with my forecasted track of this system. The upper level low is currently located in South Dakota. I expect it to dig down to around the St. Louis area, before turning east-northeast and moving through Central Illinois, Central Indiana, and Central/Northern Ohio.

In addition, this morning's models came in more robust w/ regards to precipitation. The GFS, which also was the driest of the models, bumped up our QPF by .1 - .2 inches, putting it more in line with the NAM w/ regards to precipitation amounts (the NAM is still the wetter of the two forecast models, but not by much).

Comparison: Old GFS Precip Amounts (Top) vs. New GFS Precip Amounts (Bottom). Note that this is the driest model. The third picture is of the wettest model, the NAM.



So what does this all mean for us? Well, firstly, it means I have greater confidence that portions of SE Michigan will receive 4-6" of snow. Also, due to the northward trend in the forecast models w/ regards to the precipitation shield, I will move the 4-6" of snow area up to around the I-69 corridor. North of there, there will be a fairly sharp cutoff in snow totals, but there is a very good agreement among the forecast models that we will be in the main band of snow.

In addition, I will include some areas in a "locally higher amounts" shading. First, I will include areas near the Ohio Border in this shading because they will be closer to the low pressure system. Second, I will include the "hills" of SE Michigan (eastern Livingston County, western/northern Oakland County) in this shading. The reasoning for this is twofold. First, some of the higher-resolution forecast models such as the NMM show a heavier band of snow setting up between the I-96 and I-69 corridors. Secondly, the areas on higher ground usually do well in long-lasting, moderate snowfall events, which tomorrow's event will be. Therefore I think a good compromise is including the "hills" of SE Michigan in this shading. I don't expect to see too many areas get over 6", but there will likely be some isolated amounts of over 6" in those shaded areas.

Heavier band of snow shown by the NMM's simulated radar at 11 p.m. tomorrow night

Anyways, I am expecting snow to start around 1 p.m. tomorrow and end around 4 a.m. Thursday Morning. Snow won't be particularly heavy, but it will be steady. This will make the Thursday Evening and Friday Morning commutes a mess, especially because temperatures may be low enough to render road salt partially ineffective. So, now to the part everyone is waiting for: what does this mean for our snow day chances?

It definitely increases them. I said earlier that if I had to bump forecasts into the 6" range, a snow day would definitely become possible. And it is, especially since there will not be time to plow all the back roads. I still think that there is a chance that our area in the hills sees the higher end of totals (5-6"), but everyone around us sees lower totals (4-5"), so no one calls a snow day. But it is January, and we haven't seen a snow day yet, so it could happen. Also, there's a chance that a persistent band of heavier snow sets up over us and we get higher than 6". All in all it will likely lead to the first legitimate shot at a snow day tomorrow night, and I will raise to the snow day grade to a "C" (around 50/50, could break either way based on nowcasting trends).

For now, I'll leave you with my forecasted snowfall map. Unless there are any major updates, I anticipate making my snow day prediction between 8:00 and 9:00 tomorrow night.

POST

Just wanted to let everyone know I'm working on the update...it will be up by 9.

Snow Accumulations Will Be Adjusted Upwards

No big update here, but I just wanted to say that looking at the newest forecast models, snow accumulations will definitely be adjusted upwards in my evening update. I may change this, but for now, I'm thinking 4-7" for our area. Snow day grade will probably be going up as well.

Stay tuned. Next full update around 8:30 p.m. tonight.

3-5" of Snow Expected Thursday Afternoon - Friday Morning

I'm happy to say that not too much has changed since last night's post w/ regards to the evolution of this system. Therefore, I won't bother restating the specifics of where this system is going and why it sets us up for a decent snowfall. If you are looking for those details, look to the right and click on the link that says "Interesting Storm From Thursday Afternoon - Friday Afternoon".

Anyways, tonight's focus is on expected snow accumulation and possibilities for a snow day.

Currently, I am expecting snow to start around 2 p.m. on Thursday. The snow will start off falling lightly, but will increase in intensity Thursday Evening and Overnight, before tapering off on Friday Morning. There is still some uncertainty with regards to snowfall accumulations. Not much has changed with the precipitation showing up on the forecast models, but as we are now 1 day closer to this event happening, I tend to think that things will pretty much stay as is, and therefore, I will narrow down our forecasted accumulations to 3-5".

There is an interesting possibility for more snow, though. Somewhere north of this upper level low, an enhanced band of snow is likely to set up. Here's one example from the NAM forecast model. Note the increased areas of precipitation in SE Michigan:


If this enhanced band sets up over us, which is not a slam dunk but is possible, we could see a bit more snow than I am currently forecasting. It wouldn't be anything that would give us a slam dunk snow day, but it would make things more interesting.

Now, on to the effects on the commutes and possibilities for a snow day. I expect this storm to adversely impact the Thursday Evening and Friday Morning commutes. Snow will likely be falling Thursday Evening, and may still be falling Friday Morning. In addition, cold temperatures could reduce the impact that salting the roadways may have, so there still may be snow on the roads Friday Morning even if snow has stopped falling by then.

However, here comes the part where I disappoint everyone. The roads will be bad Friday Morning, but I still don't think 3-5" of snow is going to be enough to make the school district call a snow day. I could see it if we get 6+", and that isn't out of the question yet, so I will still give us a "D" grade (school unlikely to be cancelled, but it's not hopeless yet) for a snow day on Friday. Obviously if we could possibly squeeze a couple more inches of snow out of this system than I am currently expecting, the grade will be raised. Don't give up hope yet, but don't expect a snow day either.

Anyways, that's about all I have for tonight. Hang in there, the weather pattern is getting more active for now after 2 weeks of nothing (which came at the best time, right over winter break).

Just some small updates to my snowfall map:

Interesting Storm From Thursday Afternoon - Friday Morning

An interesting situation is starting to set up for the Thursday - Friday timeframe with the next storm. Essentially, a strong upper level low is going to dive down out of the Dakotas and move through the "I" states (Iowa, Illinois, Indiana) from Wednesday through Friday. This is shown nicely on the NAM forecast model. The upper level low is represented by the "X" just southeast of Indianapolis that is shown on the picture.

As I noted yesterday, this system is not set up well to tap into the Gulf Of Mexico moisture, which normally makes for a less than ideal setup for a good snowfall. However, in this case, we have two things going in our favor.

1) High snow ratios. Temperatures as this system moves through will be well below average for early January, with highs in the lower 20's and lows in the mid teens. This puts us in a position to have something like 20:1 snow ratios, instead of the normal 10:1 - 12:1. What this essentially means is that we can get almost twice as much snow as would usually fall if temperatures were around normal out of the same amount of moisture.

2) Good dynamics. Although this system will not have too much moisture, it has strong upper level dynamics. This essentially means that this system will be efficient, squeezing as much snowfall as possible out of what moisture we do have.

What this all adds up to is around an 18 hour period of moderate snowfall from early Thursday Afternoon until late Friday Morning. Local meteorologists are downplaying this system, but I think it could be a sneaky snowfall producer. This system jumps out to me as one of those that is downplayed until the day it hits us, and then it produces more snowfall than expected. The bottom line is that we would only need 0.25" per hour of snowfall to get 4" of snow from this event. Therefore, I am currently calling for 2-5" of snow from this system.

One thing to note is that accumulations are fairly dependent on storm track. As you can see in my map below, I am calling for 1-3" of snow for areas to our north, and 4-6" for areas to our south. Obviously, we will get more snow if this storm tracks further north than forecasted and less snow if this storm tracks further south than forecasted. Therefore, amounts are subject to change but for now, I think 2-5" of snow seems like a pretty reasonable estimation. I do expect to fine tune accumulation totals as we get closer to the event, as I do realize there is a big difference between 2" of snow and 5" of snow.

Impacts from this storm...I think the most obvious one is a messy rush hour commute both Thursday Evening and Friday Morning. However, I don't think that there is a good chance of us getting enough snow to close school. For now, I'll put the snow day grade at a D (school is unlikely to be cancelled) because snow day chances would increase if the storm tracks further north than forecasted, as we would then have a shot at 6" of snow (with locally higher amounts possible).

The bottom line is that I am expecting this system to be an efficient snow producer that could sneak up on us and give us several inches of snow.

Very Cold...Snow Around Friday???

Time to start posting again as we get back from winter break. Two opportunities for accumulating snow in the next week...

First, light to moderate snow has already started to fall and will continue to fall through tomorrow morning as an upper level wave transports moisture into the area. This is really nothing major, and I only expect a widespread 1" snowfall with isolated "jackpot" amounts of up to 2".

The second, slightly more exciting possibility for accumulating snow comes around Friday this week. In this timeframe, an upper level low pressure system will eject out of the western U.S. and move through the Midwest. Eventually, a surface low pressure system will form and give someone a significant snowfall. My current prediction for snowfall from this storm is around 2-3", even though this will be a fairly dry storm. The reasoning is that because it is going to be so cold, snow ratios will be higher than normal. Therefore, what would be only 1" of snow in warmer conditions may be 2", or maybe even 3" in the cold conditions we will have as this storm passes through.

Also, I can see two possibilities for higher snow accumulations with this storm. The first possibility is that the surface low pressure system develops much further west than forecasted. The surface low pressure system is currently expected to more or less ride up the Atlantic Coast, giving the Northeast US another potentially significant snowstorm. However, as I have mentioned before, forecast models tend to put the position of these lows too far to the east at this time in the forecast. It would take a large shift west to put us in a position to receive significant snowfall from the main surface low, but it is not entirely out of the question.

The better possibility is that the upper level low taps into some Gulf of Mexico moisture. As I mentioned previously, this is expected to be a fairly moisture-starved system. However, it is conceivable that the system could tap into more moisture than is currently expected, resulting in slightly higher accumulations.

The bottom line is that the system on Friday is not currently expected to be anything more than nuisiance snow. However, this system bears some resemblance to systems in the past that have given us fairly significant snowfalls due to high snow ratios. Therefore, I will be monitoring this system and will update if it will be more significant than I have currently forecasted.