Final Forecast For Wednesday-Friday Storm and Snowflake Prediction

UPDATE: Snow has been reported in our western neighboring counties(Loudoun, Fairfax). If we are snowing at 36-42 degrees, it may be a good sign that we can support all ❆ throughout the night. More information on my nowcast post: https://mcpsweather.blogspot.com/2021/02/nowcast-for-wednesday-friday-storm.html

Unfortunately, something has occurred that if you live in the DMV, you would have seen before: Storm Disappointment. The northern trend did happen, but only for the first wave/part of the storm. We are the bullseye for the first part(the DC area). However, the second part mainly seems to just miss us to the south. That's why we are under winter weather advisories instead of warnings(in effect until 10 AM Thursday). We will see some snow in the second wave (Thursday afternoon/evening - Friday), but as of now, it's looking very limited, decreasing our overall snow totals. And now we have to throw some mixing and rain into it as well. Northern MoCo has the best chance of seeing more accumulation than southern MoCo due to colder air and less rain/mixing, but they will see less snow from the second wave.

GFS:

The GFS shows all snow for the entire county the whole time. The first wave drops some moderate snow and shows it ending around 10 AM Thursday. By now there are 1-5 inches on the ground, with the most snow in extreme upper MoCo and the least snow in Southern MoCo. Then, in the second wave, it shows some light-moderate snow hitting us, dropping an additional 1-3 inches of snow(less snow in Upper MoCo and more in Southern MoCo). When this storm is done, it drops 2-6 inches of snow.

NAM(12km):

The latest NAM does not appeal to snow lovers. It shows the storm starting out as snow, however, it shows lots of mixing and rain for the whole county during the first wave, before turning back to all snow. The second wave doesn't hit us that well at all. It shows 2-6 inches of snow, with the most in Damascus(NE areas) and the least in SW areas.

Note: I used Pivotal Weather because of the Kuchera ratio; tropicaltidbits.com doesn't have that.

HRRR:

The HRRR shows all snow for MoCo during the first and second waves.  The first wave drops 1-3 inches, with more snow in the NE areas than SW areas. The second wave, at least compared to the other models, hits us the most, dropping an additional 1-3 inches. Overall, 2-6 inches, with the most snow in NE regions and the least snow in SW regions. However, there is one thing that Tony Pann said that I want to put in. "This is the 12z run of the HRRR. See that red "L" on the map? That's a surface Low. The fact that this piece of energy has a surface reflection, tells me this snow event could have a little more gusto for the Baltimore Metro! All that to say: Snow totals could be higher."

European:

 The Euro shows the storm starting as snow(a little bit of mixing though) and then staying moderate-heavy snow until the first wave is over. The second wave remains south of us, and the Euro shows no snow at all from the second wave. Overall, the European shows 3-6 inches, with the most snow in the eastern regions(NE specifically) and the least snow in the SW regions. This is assuming a 10:1 ratio though, the ratio will be a little bit higher or lower. 

Maps:

Fox 5:

Fox 5 shows 2-4 inches for the entire county, at least for the first wave. They then show a coating to 2 inches of snow for most of the county, with the eastern section having no snow accumulation. This adds up to 2.2-6 inches of snow. Mike Thomas said that he was hesitant to bring that 4-6 inches of snow area south.

WUSA 9:

WUSA 9 shows 1-3 inches of snow for the whole county. They also said Gaithersburg, Leesburg, Frederick, and areas north of that will probably see totals on the higher end of this range(2-3 inches).

ABC 7:

ABC 7 predicts 2-5 inches of snow, with a bust being less than 2 inches and a boom being over 5 inches. They didn't give a map.

NBC 4:

From this screenshot, they think that there will be 3-6 inches of snow. The rain-snow line will be "in play" during this storm, and could affect road conditions and snow totals.

NWS:

The NWS shows 3-4 inches for most of the county, with a small portion in upper MoCo in the 2-3 inches range(don't know why). They expect the precipitation to come at 5-7 PM. 

The high-end totals are 4-6 inches, with Damascus in the 6-8 inches range.

The low-end totals are 1-2 inches of snow.

Capital Weather Gang:

They predict 1-3 inches for the first wave for most of the county, with extreme upper MoCo in the 2-4 inches range, and southern MoCo in the C-2 inches of snow range. Accumulation there will be mostly on  grass, and sleet and rain will mix in at times.

For the second wave, they think that a coating is possible for most of MoCo, and a C-2 inches for southern and western MoCo.

Snowflake Prediction:

2 Snowflakes(30% chance of offices closing {no virtual instruction} and a 50% chance of school buildings closing): ❆❆

I don't think we will have no school because offices didn't close for the storm last time and that was forecasted to have significantly more snow. I will keep you updated on the latest information in my nowcast post. 

So what do I think? Well personally, I am going for 2-6 inches of snow, 2-4 for Southern MoCo, and 3-6 for Northern MoCo. Although everyone is treating this storm like this is a complete failure, the models are showing at least 2-3 inches of snow for our region. Temps will be hovering at freezing though, and a little bit above freezing in the afternoon hours, but most of the snow should fall in the night, where temperatures should be below freezing, and there is no sun angle to hinder accumulation. The first wave I am confident should drop 1-4 inches of snow. The second wave may drop an inch or two but I have less confidence in that. I think we will see at least 2-4 inches(bottom line 1-3 inches). On my snowstorm rating system(I will be working on that more), this would be rated a moderate snowstorm, at least for northern MoCo.  Precipitation will arrive at 5-7 PM(may start out as a mix) and will continue on throughout the night, into Thursday morning, where precipitation will taper off as we wait for our second wave and enter into a lull. The second wave will start to enter on Thursday evening. It will have lighter snow accumulation and will start to clear out by Friday morning. Scattered snow showers are possible on Friday afternoon. And we have many more wintry threats coming up in the next couple of days, the next one on Saturday-Sunday, and another one on Tuesday. I would be surprised if we don't see any more snow from this pattern. Stay tuned!