First Call Snowmap and Discussion for 2/17-18/2019

Good afternoon from SCW! This discussion will include our first call snowmap and discussion for late tomorrow night into Monday.

Models and Trends
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We’ve got an interesting little model battle shaping up here with the system for tomorrow night into Monday. The bulk of the guidance has trended wetter and further north with the system to match the GFS depiction from yesterday, and now advertises a solid advisory snow event for the entire state. The Euro, on the other hand, has come part of the way there. It now brings a good band of snow into the southern portion of the state, enough for advisory level amounts in roughly the four southern counties, but in the northern portion of the state there is a sharp cutoff to just an inch or so of snow.
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Here’s a look at the total QPF from the Euro (left) and GFS (right). The Euro has a sharp spread between about a tenth of an inch of QPF in the north to about a third in the south, while the GFS has about a third in the north and close to a half in the south. Not a huge spread in the grand scheme of things, but the difference between a nuisance 1-3” event and a plowable 3-5” event. 

While it’s hard to ignore the Euro as it’s our most reliable guidance, it’s not a model that likes to make big moves, and so the fact that it’s consistently ticking further north with the system while the other guidance has held relatively steady suggests to me that the northern consensus should be favored. While I’m not going to completely toss the Euro, even a 50/50 blend of the Euro/GFS would verify a low end advisory snow for the northern portion of the state, and even if the Euro were to verify completely we’d still see advisory level snow in the southern four counties. As such, I am confident with a general 2-5” of snow for the state, with higher amounts more likely in southern areas, with the caveat that if a complete capitulation to the Euro occurs we’ll need to knock amounts down an inch or two in the northern counties.

Temps have also ticked slightly warmer across the board with the progression further north, but I think we’ll be just cold enough to remain all snow across the board. It wouldn’t totally shock me to see a brief mix with sleet or rain on the south coast, but as of now I think that’s unlikely.

Forecast and Timing

Here's our first call snowmap for this event.

As discussed, we’re going to favor the wetter consensus for the first call, and go for a general 2-5” of snow across the board. I would expect most amounts to be in the 2-4” range, but leaving a little room on the top end in case we get some isolated bands of heavy snow or the system continues to tick wetter. Conversely, if the Euro solution wins out, northern areas will be closer to 1”, but confidence in at least 2” is fairly high right now.

The timing of the system hasn’t changed much, with snow moving in late Sunday evening (around midnight Monday morning) and continuing through early Monday afternoon. I don’t expect snow to be all that heavy, but the best chance for heavier snow will be Monday morning. If you have to commute Monday, plan to leave some extra time.
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Here’s an animation of the system from the RGEM.

Impacts

Still missing the SCW impact scale (I’m flying home tonight I’ll have it back soon!) but here’s what we’re expecting:

• Snow Accumulation: Low to Moderate
• Snowfall Rates: Low to Moderate
• Wind: Low
• Power Outages: Low
• Timing: Moderate
• Road Conditions: Moderate

Schools are off Monday for Presidents Day so we don’t have to worry about any snow days, and I don’t think snow will be heavy enough to close workplaces, but do leave some extra time for your commute Monday if you need to work.
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We’ll be back with a final call tomorrow afternoon, until then, if you liked what you read, please consider sharing on your social media platforms and joining our family on ours. 
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Thanks for reading!
-SA