Thursday-Friday Storm Update and First Snowflake Prediction

The afternoon and evening models have all been trending better for snow lovers. This storm has the potential to be the biggest storm since Jan 31- Feb 3 for people who didn't get that much from it. Winter storm watches are in effect for 5+ inches of snow and 0.25+  inches of ice possible, for the entire county. This is looking like a snow-to-mix event. Temps should be below freezing the entire time, so as of now, we shouldn't be seeing regular rain. However, model trends suggest a possible switch back to snow, and even an all snow event. In this article, we will be looking at models and first-call maps.

NAM 12km (Short-Range Model):

The NAM shows us starting as heavy snow, then shows us turning into a heavy mix(sleet) before the storm is done. Now, let me tell you why this would be wrong. You see that 1034mb high over New England(interior northeast)? A warm nose with that strong of a high wouldn't be able to push in that north and west of the I-95 Corridor. And this model does have a warm bias and is an outlier. Although it usually performs well, unless other models start trending this way, I don't really buy this.

This model shows a sad 1-8 inches of snow. There is a sharp gradient in upper Northern MoCo, with the border getting close to 5-8, and elsewhere 2-5 inches(in northern MoCo). Everywhere else is along 1-3 inches. Again, the NAM is really bad with its warm nose.

European Model:

The European model shows an all snow event for Northern MoCo. For southern MoCo, it shows some mixing(freezing rain) occurring from 1-5 PM Thursday, before transitioning into all snow. It shows the snow getting out of here around 7a Friday. Although I think this is going well with this system, it might be under modeling the WAA(warm air advection) above, which would give us more mixing and ice than snow, but CAD keeps the precipitation wintry. Let's look at some snow maps.

The European model shows 6-9 inches of snow, with more snow Northern MoCo. And this is assuming a 10:1 ratio, snow ratios will likely be higher, bumping up totals to possibly 7-10 inches.

GFS:

The GFS is a snow lover's dream. It shows very heavy snow rates before turning over into sleet and then into freezing rain. It has ticked south... again. Nice to know that it corrected itself.

The GFS shows, and I have been wanting to say this for a long time, over a FOOT of snow in the border of MoCo/Frederick County! 8-13 inches, with more snow north and west than south and east. It overdid the totals, but this is very encouraging.

CMC:

The CMC has shifted south as well, giving us more snow. It shows all snow for northern MoCo and even the northern section for Southern MoCo. It shows some mixing in interior Southern MoCo, but no rain. It changes to all snow for everyone before moving out.

The CMC shows a good 8-12 inches of snow when this storm is done. And this is only a 10:1 ratio, temps will likely be colder, meaning higher ratios, meaning more snow. I think it does put too much snow on the ground but we will see...

Capital Weather Gang:

The CWG shows 3-6 inches for most of the county, and 2-4 inches for Southern MoCo. In the 3-6 inches range, a boom with be up to 10 inches and a bust in that section will be 1-3 inches. In the 2-4 inches of snow range, a boom would be up to 8 inches, and a bust would be less than 2 inches.

WUSA 9:

WUSA 9 shows 3-6 for most of the county(2/3), and 1/3 of the county(southern) is in the 2-4 inches of snow range. They think that delays and cancellations, plus snow covered roads are extremely likely, and power outages and downed trees are possible.

Fox 5:

Almost the entire county is in the 3-6 inches of snow range, with the northern border in the 6-12 inches of snow range. They are going conserative with their snow totals, understandably.

ABC 7 didn't release a map.

NBC 4:

NBC 4 thinks 2-6 inches for most of the county, and 6-10 inches for the upper cap of MoCo. They think that significant icing is likely across the blue and light blue area.

NWS:

Snow Accumulation:

Expected:

The NWS shows 4-6 inches for the entire county. Somehow, DC is in that range too, which is... unlikely, because of the snowhole, but we will see. They will somehow manage to measure an inch or two even if the entire region around it gets 10 inches...

Low-End(Bust Scenario):

This would be devastating, but honestly, as much as I hate to admit it, there is a pretty good chance of this playing out. It shows 1-3 inches of snow, with 2-3 inches for half of the county, and 1-2 in the rest(scattered snow amounts)

High-End(Boom Scenario):

The NWS shows 6-8 inches of snow for the entire county. This is a snow lover's hope; one can dream!

Ice Accumulation:

The NWS shows 0.10-0.25 inches of ice for the whole county, even upcounty. Totals would be closer to the high-end of the range in Southern MoCo. This is enough to cause major disruptions, and with the snow and sleet... it won't be pretty to say the least. Widespread tree damage, and spotty, possibly widespread, power outages will occur.

Snowflake Prediction: 4 Snowflakes ❆❆❆❆

Virtual Instruction Version: 75% chance of offices closing, and almost 100% chance of school buildings closing. 

I think that there will be no school, even no virtual instruction, on Thursday. MCPS has already canceled food distribution for Thursday, suggesting that school buildings will close. I think offices will close as well, due to the heavy snow that will fall, and the significant icing, especially in southern MoCo. Temps should remain below freezing the entire time in the entire county, so there will be no hope of some melting. It's also going to be very cold on Wednesday and today night, with wind chills in the teens and possibly lower. If there is less snow, there will be more ice. And forget in-person offices, if there is a lot of ice, tree damage and possibly widespread power outages will occur. The ice will be on top of the snow as well, causing more havoc. Snow ratios will probably be greater than 10:1 as well. We will see backend snow from this storm as well. My first prediction in snow totals will be 4-8 inches across the county, with 3-6 inches in Southern MoCo, and 4-8+ in Northern MoCo(notice that plus, it means higher amounts possible). My first ice accumulation forecast would be 0.1-0.25 inches of ice for Northern MoCo, and 0.2-0.5 inches of ice in Southern MoCo. Snow will start to move in the night hours of Wednesday, and the precipitation(snow most likely) will move out around Thursday night. Snow is possible into Friday, but everything should be done by Friday afternoon. The bulk of the snow and precipitation will fall between 7a - 9p Thursday. This will be highly dangerous, and will be life-threatening, not only because of the snow, but because of the ice. The ice is the main concern for Southern MoCo, but the snow will also be a big concern. I hope that we see more snow than ice, and I think even the people who don't like snow that much can hope for that too. Do not travel on Thursday; it will be extremely dangerous and life-threatening, and will be impossible at times. Power outages and tree damage is likely. Be prepared for outages. I will have an update when tomorrow's afternoon models come in.