Final March 13 Blizzard Forecast ~ Important Changes From Yesterday, So Please Read It Carefully!

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Good evening weather world,

I hope your day went well while preparing for tonight into tomorrow’s winter storm.

In this forecast I will detail the latest trends that I have been seeing and then give you all my forecast as well as detail it for specific areas in the Northeast. (I will try to keep it as short as possible, I promise!)

Below is a picture of our storm on a water vapor loop–She looks like a monster already.

Below you can see where the Blizzard warnings and winter storm warnings are for around the tri-state and the Northeast:


You can look for snow to begin in the area earlier than I said yesterday, around 10PM-midnight tonight in the New York City Metro area. The snow should start to taper off by mid-afternoon tomorrow. After that, it will be cleanup time.

***Before I get into any specific details, I need to make sure that everyone is aware of the latest forecast trends and data coming in today. If you can remember, on Saturday I was worried about the storm track coming to close to the coast, causing serious mixing problems for our area. Yesterday, as you can see in my update, all of the data that I had led me to believe this storm could be historic, with 20 inches or more possible. LATE LAST NIGHT AND ALL DAY TODAY THAT CHANGED ONCE AGAIN. After analyzing the data, the storm track will now be closer to the coast tomorrow. This means that we will have to deal with serious mixing issues all the way west to I-287 in New Jersey (The Morristown area). This will all be dependent on the rain/snow line. The rain/snow comes down to whether or not the upper levels of the atmosphere can stay cold enough (below 0 degrees celsius) to fall as all snow. If at 850 MB for example, a warm layer moves in, your snow will change to sleet. If the storm is strong enough, however, it does have the possibility to produce its own cold air, keeping it all snow throughout its duration. And guess what? No one can exactly know where this will set up, so I have had to try and figure out my best possible guess on it.

To give a recap of the computer model information, ALL of them now include this mixing with sleet as well up to I-287 in New Jersey, and especially up to I-95. Two models I like to look at this close to an event with a rain/snow line issue are the RGEM, the NAM, and the EURO. The RGEM and the NAM are short-term high resolution models that forecast things like a rain snow/snow line. The European model is one of the best computer models we have in the world for weather. The NAM is the warmest solution for NYC, causing lots of mixing and only drops 5 or 6 inches on us, followed by heavy sleet and then rain. The latest Euro drops 16 or more inches of snow in NYC. The RGEM is somewhere in the middle. So what do I take from this and one reliable model showing only 5 inches and one up to 16 or more inches? Basically that my life will be very hard over the next 24 hours! I am going to do my best though with the data that I have.  (It also seems like the news and media is over-hyping this storm. If mixing takes over, the snow totals and conditions will be nowhere near what they’re saying). Stay close to my page for updates as we move forward.

With all of this being said, here is what the bottom line is. If the storm comes even further west, mixing will drastically reduce snowfall totals. If the storm can track a little further east, even by 30-50 miles while also becoming stronger and pulling in colder air from stronger dynamics, extremely high snowfall can occur. To be honest, I will not know what exactly will happen until the storm is occurring. What I do know is that before the changeover to sleet occurs, HEAVY, HEAVY snow will be falling. It could be the heaviest you have ever seen, right around the morning rush hour. But when does that changeover occur? Is it at 6AM , 8 AM, or 10AM. This makes all of the difference. (By the way, I urge everyone to stay home tomorrow. You do not want to go out in this.) Before the changeover and mixing, 1 to 3 or even 4 inches of snow will fall PER HOUR. That is some crazy snowfall rates. Make sure you have your shovels and snow blowers ready. This will be a heavy, wet snow for the NYC metro which will unfortunately be very hard to shovel. There will be snow packed roadways, visibility down to 0, and major coastal flooding and beach erosion due to this Nor’easter. The winds will also be very strong, which makes me nervous for power outages close to coastal areas and trees falling down from the heavy, wet snow.

I am now going to give you my best possible forecast for the Northeast, U.S. This time, however, since there is a possibility that the storm trends colder, I am going to give a forecast for the highest potential snow as well. Snowfall dramatically increases as you move further north and west of the city. The city will be the battle ground I think, with sleet and rain east and snow,sleet and (hopefully not rain) to the west.

New York State: (By county)

Orange County: 18-24″ + inches of snow

Rockland County: 17-24″ + of snow

Northern Westchester: 15-20″ +

Southern Westchester: 8-16″ ~ Potential for this much if the storm ends up colder with less mixing: 15-25″

Bronx: 7-15″ ~ Potential for this much if the storm ends up colder with less mixing: 14-24″

New York (Central Park): 7-15″~ Potential for this much if the storm ends up colder with less mixing: 14-24″

Western Long Island: 6-13″~ Potential for this much if the storm ends up colder with less mixing: 12-18″+

Eastern Long Island: 2-7″~ Potential for this much if the storm ends up colder with less mixing: 7-14″

Now for New Jersey: (Remember, the snow amounts are so different that if you travel just 5 miles west or north from your current location (Nutley to Wayne for example), the snow totals can go up greatly.

Sussex, extreme northern Passaic, and northwest Bergen counties: 15-24″ +

Northern Warren and Morris counties: 12-20″ + of snow ~ Potential for this much if the storm ends up colder with less mixing: 15-25″ +

Southern Morris county: 11-17″~ Potential for this much if the storm ends up colder with less mixing: 15-25″

Western Essex county (Fairfield, NJ): 9-17″~ Potential for this much if the storm ends up colder with less mixing: 15-25″

Southern Passaic county: 9-17″~ Potential for this much if the storm ends up colder with less mixing: 15-25″

Eastern Essex (Nutley, NJ), northern Hunterdon, Southwestern, CT and Hudson counties: 8-17″~ Potential for this much if the storm ends up colder with less mixing: 15-25″

Union County: 7-16″~ Potential for this much if the storm ends up colder with less mixing: 15-25″

Central/southern Warren and southern Hunterdon counties: 7-14″~ Potential for this much if the storm ends up colder with less mixing: 15-25″

Somerset and northern Middlesex counties: 6-12″~ Potential for this much if the storm ends up colder with less mixing: 12-20″+

Monmouth county: 3-9″~ Potential for this much if the storm ends up colder with less mixing: 9-14″ +

Jersey Shore: 2-7″~ Potential for this much if the storm ends up colder with less mixing: 6-13″+

Philadelphia: 5-13″~ Potential for this much if the storm ends up colder with less mixing: 14-24″

Baltimore: 2-6 inches~ Potential for this much if the storm ends up colder with less mixing: 7-14″

Washington D.C.: 2-5 inches ~ Potential for this much if the storm ends up colder with less mixing: 5-11″+

Boston: 6-12 inches~ Potential for this much if the storm ends up colder with less mixing: 12-20″ +

There you go everyone. That is my forecast. If you have any further questions, please let me know!

Sometimes the models can often underestimate mid-level warmth. This is why certain areas will see mixing which will reduce totals. I-95 is the battleground for this I think like I have precisely mentioned! You also have to keep in mind that dynamic cooling from strong storm systems like these can cause the storm to be colder. Hopefully I was as close to what happens as possible! I will update this in the morning and zone in on where I think the rain/snow line will set up as well as with updated totals if needed. I will also pinpoint where the heavy snow bands seem to be setting up which will cause specific areas to get more snow totals than others. Hopefully there is no dry-slotting with this storm as well. I do think we will have some surprises too since this storm is so massive.  

Here are some graphics that I think are good to look for this winter storm:

Possible snowfall rates per hour as seen by where you live. (Look at the lower Hudson valley. This model shows up to 5 or 6 inches per hour. That is probably overdone but shows just how strong this storm can be). Source: WxBell


On these two maps you can see how far north the rain/snow like can get, decreasing  snowfall totals (The very top red line is the changeover line). Source: Tropical Tidbits


This graphic below shows on the top left, as well, how far north the icing can go as well as how far north and west the rain shield may go on the bottom left. Source: WxBell


This picture shows the heavy thump of snow we will be getting before the changeover to sleet may occur. Source: Tropical Tidbits

I like these two maps from the National Weather Service ONLY because they detail what will happen if no changeover occurs from mixing occurs (highest snowfall potential for the NYC metro) and the other picture details what happens if a lot of mixing occurs (lowest snowfall potential) by county. *These are not exact forecasts

If you can see this map, I like what it shows for snowfall around the region. The snow key is on the bottom with inches. 


That’s it for tonight! Please everyone be safe and I will speak with you tomorrow!

Joe (Snow) Codomo!!!!

 

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