Second Wednesday-Friday Storm Update and First Snowflake Prediction

 This storm is a very difficult one to predict, however, I have good news for snow lovers: This should be an all snow event, regardless of amounts. However, this is a long duration storm. And the last long-duration storm, models were very jumpy and had so much disagreement, even 1-2 days out. Watches haven't been in effect yet for us and the general DMV(excluding western MD). Even with that being said, we are at a point where everyone should prepare for an impact on their day. But just how much snow are we looking at? We will try to answer that question using models.

Models: 

GFS:

The GFS shows an all snow event(mixing in western MoCo is a bug because upper air temps below freezing). It shows 2 waves, however. The first wave drops a good 2-4 inches, with less snow in the southern suburbs and more snow in the northern areas. Then, there is a dry period of no snow. Then, we start snowing again, and we into the second wave. This wave drops another 4-6 inches of additional snow onto the snow that already fell. It shows a good 6-9 inches of snow when this storm is said done.

The American model is more northern based than the other models, as you will see shortly. It shows more snow in our NW areas and less in our SE areas. However, in the first wave, dry slotting and not having enough moisture is a problem cause that could easily happen; models don't pick up on it too much. Cold air isn't an issue here though. And the second wave has much more energy and potential than the first one.

European:

The European became less bullish with its storm. Like the GFS, it shows 2 waves, they both start and end at around the same time, and there is a dry period before the next wave. However, the European has shifted south. Again. I will show you the snow map, however, I have some good news along with that.

The European model(sad violin please) shows ONLY 3-5 inches of snow(totally), with less snow in the NE part and more snow in the SW part. However, this is a 10:1 ratio, and the ratio will likely be bigger than this, meaning more snow. Sticking shouldn't be a problem; as most of it should fall in the night. I have some bigger news though. Before the last long-duration storm(Jan 31 - Feb 3), the European model was trending south, and in the last minute, it trended north, giving parts of PA over 30 inches of snow. 

Now, we won't be seeing that much snow, but the bullseye should go NW, giving the DC area the most snow out of this storm. It's called last-minute for a reason. :D

NAM(12km):

The NAM shows an all snow event. The moderate-heavy snow lingers for a while before quickly moving to the south. The second wave seems to miss us as well. I don't think we won't see the second wave miss us, because again; the northern trend. I have never seen it not happen with these kinds of storms. Remember Jan 31 - Feb 3, and how the models shifted to give PA/NJ the bullseye of that storm, some areas getting over 30 inches. 😀

CMC(GEM):

The GEM shows the storm starting as rain(I doubt it will happen, we have a sufficient supply of cold air). It shows the first wave dropping a couple of snow, which is moving SE, then another wave coming from the west hitting us, moving NE, and going off to the coast. 

It shows a good 6-10 inches for MoCo, with more snow in the SW areas than the northern areas. But again... that north trend. I wouldn't be surprised if it shows Northern MoCo getting more than Southern MoCo. If that bullseye moved a bit north, our county would be right in the jackpot. And this is a 10:1 ratio, numbers will likely be higher than this due to the atmosphere being colder.

Maps:

National Weather Service:

Expected:

The NWS is counting in the NW trend, and I think that is what people should do for this storm because it always happens. It shows 6-8 inches for all of MoCo. I like how they are playing with this storm.

High End:

The NWS shows 8-12 inches of snow for the whole county if this storm were to boom.

Low End:

The NWS shows 2-3 inches for most of the county, with 3-4 inches for super NW MoCo. This would happen if this storm busted. 

The National Weather Service shows a moderate threat of a winter storm for the entire region from Thursday-Friday. This hasn't occurred since 2019.

Fox 5:

Fox 5 shows a good 3-6 inches for our county. Mike Thomas said that they are on the low end of totals compared to guidance due to many unanswered questions. I understand why, but that northern trend should at least put us in the 4-8 inch range.

 

WUSA 9:

Note: this is only until Thursday evening, additional snow will fall on Thursday Night - Friday. They show 3-5 inches for upper MoCo and 1-3 inches for the rest. I think they are going a little conservative with the snow totals, but that is fair.

Capital Weather Gang: 

They show 3-7 inches for Western MoCo and 2-6 inches for the rest. I agree with this map more than the other ones, cause it does give the potential for over 6 inches. 

NBC 4 thinks 1-3 inches for the first wave and 1-3 inches for the second wave. Storm totals across the county add up to 2-6 inches of snow. Again, it's good to play conservatively for your first call as more data comes in. ABC 7 also thinks 3-6 inches of snow. 

So what do I think? For my first forecast, I think that we MoCo will see 4-8 inches from this storm. We won't probably see any kind of mixing, and we should have sufficient cold air in place; meaning that the snow to liquid equivalent ratio will be above 10:1 like it normally is(good for snow lovers). Surface temps should be cold enough to support accumulation and to help us, snow lovers, even more, most of the snow should fall during the night, where there won't be a sun angle to hinder accumulation. This will be a high impact storm, and you should take it seriously. The second wave of snow will probably bring more snow along with it, as it is more powerful. The NWS has a moderate threat for the entire region(not just the northern or southern part, hasn't happened in around 2 years or so). This might be the biggest snow of the season for Southern Maryland, and maybe even since 2016. 

Snowflake Prediction: 

For a snowflake prediction, there is still so much we don't know about, but for now, I stand at 3 snowflakes. School buildings will probably close on Thursday, but offices may not, because there will be a lull between the transition to the second wave, and I think that Montgomery County will try to do a delay or something so that they can go to work at the lull. There is still so much that we don't know yet, and we have to see live conditions to make a proper prediction. I will make a final call tomorrow with a stronger snowflake prediction. I will also be doing a nowcast for this storm, while its raging on, so you can get live conditions and updates.