Author: Alex G

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February 17-18 Storm Update

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Tonight’s storm is proving to be a tricky one to forecast, a difference of 20-30 miles in the track of the storm will mean a significant difference in snowfall totals. As of now my forecast for tonight is as follows: Precipitation will overspread the region from West to East beginning around 6 or 7 PM. Precipitation may be in the form of rain or light snow, I’d lean towards light snow in NYC and Western areas and rain the further East you go on Long Island. The precipitation will begin to change to all snow during the evening, with the changeover happening earlier further North and West first. Precipitation will end by sunrise Sunday morning. This is looking like a classic storm where the North Shore of Nassau and Queens/NYC will see an earlier changeover than the South shore and Suffolk. As of now, the battleground for Rain/Snow looks to be the LIE in Nassau county and Queens, in Suffolk the changeover line may be closer to 347 or 25. I will caution that if the storm tracks further North or South the changeover line will have to be adjusted. I probably will have a better idea of where this line will set up this evening as the storm is starting. Below is my first guess/call for this storm, but I’ll caution that I have lower confidence than usual in this forecast.  One final thing to keep in mind is that tomorrow temperatures will rise into the lower 40’s and whatever snow does fall will likely melt during the day.

 

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February 17-18 Snow Event

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It looks like our luck has run out and we are likely to see some snow overnight Saturday into Sunday. As of this afternoon, it is difficult to lock down exact totals, since our area is right on the border between rain and snow. It is likely that parts of the North Shore of Long Island and Northern parts of NYC will be seeing heavy snow while the immediate South facing shores will be raining. As of now, my best forecast is that light snow and/or rain will overspread our area late Saturday night (8-11 PM time frame) and continue until around sunrise Sunday. Depending on the exact track of the low and strength, snowfall totals may end up being under an inch in some areas to as high as 5 or 6 in others. For now, the safe call is 2-4″ on the northern half of the Island, and 1-3″ on the Southern half. The other key factor in all of this is temperatures on Sunday and Monday will stay above freezing, and therefore whatever snow does fall will melt quickly. More updates to come tonight and tomorrow.

Below are a few examples of the potential snowfall, showing the wide variance in guidance:

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1/4/2018 Storm Final Call

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The snowstorm that will impact our region has formed and is already over performing in parts of the south. Based on current radar returns, the storm is staying close to the western edge of modeling. However, the models continue to shift back and forth by 25-50 miles, the latest NAM run shifted East a bit, while the RGEM shifted West.

What this means for all of us is that we’re all going to see moderate amounts of snow with some locations on Long Island potentially seeing over a foot. Snow will begin to overspread the area by about 4am, with the heaviest snow beginning around sunrise and continuing until the early afternoon. As I mentioned earlier, the snow may fall at 1-2″ inches per hour, with winds gusting over 30mph. It is likely many will see blizzard and whiteout conditions during the day tomorrow. The snow should end from West to East by mid-to-late afternoon tomorrow. I have outlined my final thoughts on total accumulations below. It is likely that we all will exceed the minimum forecast, and I would not be surprised if some exceed the maximum forecasted amounts.

After the storm exits the region, the coldest air of the season will come into our area, highs on Friday may not get get out of the low teens. The cold will remain through the weekend, but by early next week daytime highs should finally hit the 30’s

Final snowfall forecast:

 

 

 

 

 

 

 

 

Here are some radar and satellite shots of our developing storm:

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1/4/2018 Storm Updated Forecast

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We’re finally starting to see something nearing consensus for tomorrow’s storm. Below find my second call for tomorrow’s storm, and I plan on posting one more later tonight once the 0Z models start rolling in. I do want to mention that for these totals it is possible that we will exceed the maximums, in Nassau and Suffolk depending on the track, and the city may end up below the minimum. (Yes I know typical weather person hedging their bets)

Snow is expected to begin between 2am and 5am Thursday morning. It will pick up in intensity during the morning, and continue until late afternoon. During the storm, snowfall rates may exceed 1-2″ per hour with winds gusting over 30 or 40mph, leading to blizzard conditions and drifting snow. While this storm will not feature the heaviest snowfall we have seen in the last few years, it will be very intense between the winds and the snowfall rates. Currently Suffolk County is under a Blizzard Warning and Nassau and the City are under Winter Storm Warnings. I expect  the Blizzard Warnings to be extended to Nassau County if recent trends hold. More to come later.

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1/4/2018 Storm Update- MODEL MAYHEM

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I’ve been asked by many for an update so here it is:

The reality is at this point, there is still significant disagreement amongst the models and I can’t say with certainty how much to expect. As I said yesterday, the low is just forming and all the players are finally coming together. The dynamics involved are highly complex, and slight differences in model interpretations are leading to huge differences on the outcomes. The NAM currently is showing an area wide snowfall of 8″+ (This includes NYC), the GFS is right around my first call last night with only a slight bump up on Long Island, the CMC is lost, the RGEM is going back and forth between the NAM totals and the GFS. Needless to say it’s very hard to give a definitive snowfall amount as of now. The confusion is so great that the NWS is actually sending up Hurricane Hunter planes this afternoon to get readings over the ocean due to all this uncertainty. This all is very similar to our surprise big snow storm two years ago, when we went from a 2-4″ storm to over a foot with only 8-12 hours notice. For now, I’m sticking with my first call from last night, but it’s subject to significant change. I’ll keep you posted.

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1/4/2018 Snowstorm First Call

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Model disagreement continues this evening, with the models waffling back and forth by 50-100 miles. Which as I mentioned this afternoon can mean a significant difference in total snowfall. My forecast below is a first call and will very likely change by tomorrow evening. At this point, I’m thinking that we’ll be impacted by a moderate snowfall region wide, with more snow the further east you go. The snow will begin before sunrise Thursday and continue through most of the day. Due to the strength of the storm, it likely will be fairly windy as well, and of course cold.

First Call Map:

 

 

 

 

 

 

 

 

SIM Radars from RGEM and NAM: