Superbowl Sunday Storm Update

 As I said earlier, the models are trending northwest. And it's not done yet. We are now about 2 days out from this storm. But as you saw earlier last week, even when we get close to the storm, the models can still can be all over the place with disagreement left and right. This storm will be quite short, starting in the early morning hours, and will move out around the afternoon-evening hours, but heavy snowfall rates will make up for the short duration. Winter storm watches have been issued for the entire county, including surrounding counties, which starts at 9 PM tomorrow and ends at 3 PM Sunday. As it is looking right now, southern Maryland seems to be getting the most snow out of this event. We will start looking at snow totals from models, since we are not that far out. 

GFS:

The GFS shows the storm starting as light snow at around midnight Sunday, then shows it ending around the afternoon hours. Although this storm is short, it shows heavy snowfall rates to compensate for it.

The GFS shows 3-4 inches for the entire county and 3-6 inches for the general DMV. Although I do agree with this map, I also think that if we get really heavy bands, our county can possibly push over 6 inches. Surface temps + temps in the air are marginal, which means hovering at or above freezing. Even with that being said, there seems to be not much mixing with this event. If it's snowing fast though, it can cool down surfaces enough to become cold enough to support snow. We will see tomorrow's runs and decide.

European Model:

The European model shows the storm starting as moderate-heavy snow around Sunday morning, then shows it tapering off in the afternoon hours. It does show a little bit of mixing in southern MoCo, but I don't think that's the case, since upper air temperatures remain below the freezing mark. It has moved northwest(just like the other models) for this storm.

The European model shows 3-5 inches of snow for our county, lower totals in Northern MoCo, higher totals in Southern MoCo. The trend is shifting north for us, so I wouldn't be surprised if it changes so that Northern sees more than Southern. 

NAM(12km):

The NAM shows the storm starting out as rain, but then turning over into all, heavy snow. The rain will cool the atmosphere enough to support snow, so thats good if it happens. It shows the storm starting at around midnight and shows the storm ending by the evening hours. Now, if this went right, this could dump a lot of snow on us. The next image below shows high, unrealistic(at this point totals). The NAM does have a wet, snowier bias, so keep that in mind.

The NAM shows 6-8 inches of snow in MoCo alone! Now, would I love to see these totals? Yes. But do I think its realistic? Possibly. I don't think we will see totals that high, but once tomorrow comes and we have more information, we will have a better idea of what to expect.

MAPS:

Capital Weather Gang:

The Capital Weather Gang shows 1-3 inches of snow for the entire county. However, they did state that based on the model trends, their revisions are more likely to go upward(more snow) than downward(less snow). For the first call, it is good to stay conservative, and I understand why they have generally low totals.

National Weather Service:

The NWS usually goes conservative with their maps at first, but this is looking pretty good compared to other maps. It shows 4-6 inches for the upper third of the county and 3-4 inches for the rest. Overall, a range of 3-6 inches. I agree with the map the most, however, I am not sure if the upper side of the county will get more than the southern side, since that is what models are showing right now, but we will see.

WUSA 9:

WUSA 9 shows almost all of our county in the 2-4+(plus means higher amounts possible) inches of snow range, with a small sliver of northern MoCo in the 1-3 inches of snow range. 

Fox 5:

Fox 5 shows 3-5 inches of snow for our entire county(sorry for the bad quality). I actually think this is one of the best maps because they are really factoring that north trend and going somewhat confident with their totals, and where they reach.

(I couldn't find ABC 7's and NBC 4's maps, I will be including them plus another map tomorrow)

So how much of an impact will this have? Not much, but the morning commute on Sunday could be difficult. This is wet, heavy snow, but since temps(including surface) are marginal, snow might have a hard time sticking. If we have heavy bands, snow probably will stick on untreated surfaces. This event will be a short-duration event, unlike the last one we had. Heavy snowfall rates will make up for it though. The watches may turn into advisories or warnings; it could really go either way. For MoCo, my first prediction is 2-5 inches of snow, with higher amounts possible and likely if heavy bands intensify and fall. I won't say anything else, since I need tomorrow's afternoon models to say otherwise.