First Significant Snowfall of the Season

 Update: All schools in MoCo have closed for tomorrow

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Overnight, models have trended towards the better for snow lovers. The model runs have only been getting better and better for snow. All of the models have either trended NW, or stayed in the same place. Also, every model has been trending more amped(powerful), and reserved(slower), which means that when we get snow, its gonna be dumped on us. The storm on radar also looks more amped and NW compared to what the models were showing, which is very good. Southern MoCo is in a WSW(3-7" expected), and Northern MoCo is in a WWA(2-4" expected). Near blizzard conditions are possible with this storm. If NW trend continues, Northern MoCo will be in the WSW too. Snow rates between 5a - 11a tomorrow are the heaviest, with rates being 1-3", and with <32 temps, it will not take long for the morning commute to descend into chaos. I'll be making my snowflake prediction for school closings, and my snow forecast!

Euro:

 Euro shows 8-10" of snow for MoCo, and it's solution is similar to the 21z RAP.z

 

The Euro ensemble has >90% for almost all of MoCo to see 3+ inches of snow. The extreme northern part of MoCo has a 80-90% chance, which is still VERY high.

SREF:

This is the SREF mean. It shows 6-12 inches for MoCo and south. At the start of the storm, it will take a while for the ground to cool, but oh it will cool very fast once it really starts to snow. This isn't kuchera, so it will be inaccurate. At the start, snow ratio will be less than 10:1, but when the heavy snow starts to pick up, and temps start to drop, the ratio will be more than 10:1. Overall, the SREF mean shows a significant snowfall for our area. 

NAM:

(Credit: to dollar monkey#6663 for telling me this)

I don't trust the snow amounts and the ptype map on the NAM, but my friend saw something on vorticity that was really interesting. The area that was circled could potentially have a heavy snow band in that area, which would increase totals. Bands always form north of what is modeled, and this one looks to do just that. There is a tail at 700 mb vorticity, and that usually means that north of it gets a heavy snow band. Hence, I think that a heavy snow band will form in this area. The first image is an alternative scenario where the band sets up further south, and the third image is a scenario where it sets up further north. I have a more confidence for the third image(FGEN at 700mb supports this, second image), and the band will set up in the DC metro region. This was something interesting I found on the NAM 12km.

 

GRAF:

 

This is the GRAF model. I don't have access to this model, but I was able to find it online. It shows 6-12 inches for almost all of our region, including extreme southern Frederick county and south of that. It shows 12-18" of snow for parts of eastern MD and DE, which might be a little too extreme. I am not sure how well this model does, but I heard that it does really good with these types of events. This shows a widespread significant snowstorm for the DMV.

RAP: 

 

This is the RAP. It shows a widespread 6-12", with SoMD getting the highest totals. MoCo gets 8-10" of snow, which is a VERY substantial amount. I would say that this wouldn't be as extreme, but the storm as of 5:52 PM looks much more stronger and amped on radar, with more moisture, so this could indeed verify.

My Snow Forecast:

 

This is my second call for snowfall for the January 3rd event! It's pretty self explanatory what the totals are, so I'll go over why I made it like this. I feel like this storm will over perform. On radar right now, the storm is more north, and is much more amped than high-res models were showing, which is a very good sign for this storm to boom. I was talking about the possible location on where the heavy band sets up, and that would increase snow totals significantly due to a good thump. Because of models overall trending for the better, and the observed storm is doing better than what was expected, I made the snow totals more widespread and increased them. DC and south is going to receive 6-12" in my opinion because of the heavy thump of snow and possible banding forming there. I think 5-9"+ for central and semi-northern MD(MoCo) because of the storm going a tad bit north with much more moisture. There is a possibility that the 5-9 area could see more than 9 in localized spots because of heavy banding moving north. Snow rates will be extremely heavy with this storm, and will overtake ground temperatures quickly. It will start off as rain before quickly turning into snow.

 

As for the snowflake prediction: 4.5 Snowflakes

 

I am very confident in schools closing for this system. 1-3" rate snowfall during the rush hour is a recipe for disaster. Crew won't have enough time to fully treat the roads, and the initial rain will wash off some of the salt and make it less effective. Winds are also going to be very gusty, further creating a visibility problem. I just cannot see how schools will open, even on a 2 hour delay.