Detailed Forecast

A storm system will approach from the southern Ohio Valley on Wednesday.  With plenty of cold air in place, we’ll see a widespread snow event break out across the Hudson Valley during the morning.  However, instead of seeing the low pressure jump to the coast and redevelop… the low pressure will hug the coast, and actually track just inland.  This will allow a surge of warm air… both at the mid levels of the atmosphere, and at the surface… to push into the Hudson Valley.  As a result, as we move through the afternoon on Wednesday, most of us will watch the snow transition to a mix of sleet and freezing rain… before some of us see it turn to a plain cold rain before ending.  Let’s take a look:

Timing

• 7am to 10am: Snow begins from west to east across the Hudson Valley
• 10am to 1pm: Snow falls heaviest across most of the region
• 12pm to 2pm: Snow mixes with/changes to sleet & freezing rain south of I-84
• 2pm to 5pm: Snow mixes with/changes to sleet & freezing rain north of I-84 (mix turns to rain south of I-84)
• 6pm to 9pm:  Rain & Mix tapers of from west to east

Snowfall

• Catskills (Zone 1 & 2) : 6 to 10 inches
• Majority of the Hudson Valley (Zone 3, 4, 5, 6 & 7): 3 to 6 inches + tenth of an inch of ice
• Lower Hudson Valley (Zone 8): 2 to 4 inches + tenth of an inch of ice
• Extreme Lower HV (Zone 9): 1 to 3 inches + some ice

Discussion

The major change from our preliminary forecast is that the center of low pressure is going to track inland, instead of off the coast.  Without a deepening trough and an upper level low pressure to push the storm off the coast… this system wants to track just inland.

At first your eyes will be drawn to the snow and wintry mix on this radar… but if you can, try to spot the red “L” indicating the low pressure that starts out over Kentucky and West Virginia (bottom left of the graphic).  Notice how it pushes up through Pennsylvania, and right over the Hudson Valley, before pushing into Massachusetts.  This tremendously western track, allows copious amounts of warm air to surge right up the coast, and into the Hudson Valley.  So despite tons of cold air in place, and lots of moderate to heavy snow on the map initially… most of us will change over to a wintry mix… and possibly even rain in parts of the area.

Take a look at the 850mb temperatures with this storm.  It shows that there is PLENTY of cold air in place when the snow arrives on Wednesday morning…

This is the temperature profile at cloud level, where the precipitation forms, and falls to the surface.  Where you see white… temperatures are below 0°C, cold enough for that moisture to fall from the cloud in the form of snow.  At 7am… temperatures at the ground will be in the 20s… plenty cold enough for that snow to fall all the way to the surface.  So we expect several hours of steady, moderate snowfall across the region.

But watch what happens as the day progresses, you may notice that red and white box at the bottom left of the image, indicating the strong SW flow that is setting up.  As the low pressure tracks NE, into the Hudson Valley… it’s going to pull all that mild (above freezing) air… right up into the Hudson Valley.  By 4pm… here are the 850mb cloud level temperatures…

Notice that all the cold (below 0°C) air has eroded out of the Hudson Valley.  This means that whatever falls from the cloud at this point, will fall as liquid rain.  Now… if the air is cold enough near the ground, that liquid rain may refreeze into sleet or freezing rain.  Much of the Hudson Valley will see that be the case, as temperatures are expected to hold in the upper 20s to low 30s at the surface.

So we anticipate a several hour period of sleet and freezing rain across the Hudson Valley, once the snow changes over.  So that means on top of the snow… a layer of sleet and freezing rain will accumulate.

So in terms of the forecast… we have lowered the snowfall totals in accordance with the development of this inland storm track.  If the storm were to track just off shore, we’d be talking about widespread 4 to 8, or even 6 to 12 inch snowfall totals.  But you can see on the model simulation, the heaviest snows are pushed out of the Hudson Valley… with the exception of the Catskills…

So as always, we’ll track the storm through the event.  There can… and will be… surprises.  There always are.  So we’ll need to keep an eye out as the storm unfolds, to see if the heavier snow bands can really do their work before the milder air pushes into the Hudson Valley.  Remember… despite the slightly lower snowfall totals… conditions will still be treacherous on Wednesday.  3 to 6 inches of snow, followed by sleet and freezing rain will still make for extremely icy travel.  So use extra caution.

Be safe… and have a nice Wednesday…

No major changes to the Preliminary Storm Forecast at this time.  We’ll have the ‘Finalized Storm Forecast’ later this evening, likely before 11pm… hopefully sooner if we can.  So let’s take a quick look at how things should unfold Wednesday morning…

Snow likely breaks out from west to east between 7:30 am and 9:30am from west to east across the Hudson Valley.  Once it begins to fall, it will quickly intensify and fall moderately.  A steady snow will fall straight through the noon hour, possibly heavy at times.  Expect reduced visibility, and rapidly deteriorating travel conditions.  Temps will be in the mid 20s… so the snow will accumulate on all surfaces.  If you’re going to try and get things done early on Wednesday… please be aware that once it begins, conditions will get treacherous quickly.

As we approach mid day, we’ll begin to see the milder air creep north through the Hudson Valley.  That means a transition from snow… to sleet and freezing rain, from south to north during the afternoon.  Here’s a snapshot of what things may look like by 1pm.

You’ll notice that the milder air at 850mb (cloud level), is quick to press northward.  By 1pm… anyone near or south of I-84 will begin to mix with sleet and freezing rain.  The further south you go… that earlier the transition to ice.  As you go north of I-84… the odds are good that it’s all snow into the early/mid afternoon.

Between 2pm and 5pm, we will continue to track that snow/ice line… as it moves further and further north.  The latest data, suggests that the snow mixes with or changes to sleet and freezing rain, all the way up to Kingston and even a bit north of there.  So we’re going to continue to monitor the situation, and have to make some minor adjustments to the final snowfall forecast this evening.

We’ll have another update in a few hours… as well as the final snowfall forecast later tonight.  Have a nice evening!

A storm system will develop in the southern Ohio Valley on Tuesday, and push into the Hudson Valley early on Wednesday.  The result will be a combination of snow, sleet and freezing rain… across the Hudson Valley, that will last through the day.  By the time the storm exits Wednesday evening, we could see a wide range of snowfall amounts across the region.

Timing

• 7am to 10am… Snow develops from west to east
• 12pm to 2pm… Snow changes to sleet & freezing rain south of I-84
• 2pm to 5pm… Snow mixes/changes to sleet & freezing rain I-84 to Kingston
• 6pm to 9pm… Snow/Mix tapers off from west to east

Snow Accumulation

• Extreme Lower HV (zone 9): 1 to 3 inches
• Lower HV (zone 8): 2 to 5 inches
• Mid HV, southern Catskills (zone S3, S4, 5, 6 & 7): 4 to 8 inches
• Catskills, Taconics, Upper HV (zone 1, 2, N3, N4): 6 to 12 inches

We will provide a more detailed analysis of how the storm plays out later on Tuesday morning.  Please check back here, for an updated Discussion, as an updated addition to this post.

After a sloppy soup – super bowl Sunday… that featured widespread wet snow, mixing with and changing to rain across the valley areas… Monday will see a return to the bitter cold bite of winter.

A northwest wind will usher in the bitter cold once more.  Winds will blow at 10 to 15mph for most of the day, gusting upwards of 25mph at times.  When you factor in temperatures that will be in the mid to upper 20s across the region, you get wind chills in the single digits and teens across the viewing area.  It won’t matter that there should be a good deal of sunshine… the chill will negate any warming effects of the sunshine.

Looking ahead… we’re tracking a storm system for Wednesday.  When this storm first popped up on our radar, it looked like a warm storm, with rain…  but the trend has been colder and colder the past 2 days.  So as things stand right now, we may have a rather substantial snowstorm on our hands for Wednesday…

We’ll have to watch the details closely… because the exact track of the low pressure system remains uncertain.  But the map shown here is our best guess at this time.  Snow would push into the Hudson Valley near sunrise on Wednesday, and fall moderate to heavy at times through the day.  If the storm tracks as close to the coast as you see here (depicted by the red L), it would pull enough warm air north at cloud level, to mix the snow with sleet and freezing rain.

However, even in the scenario shown above, a substantial amount of snow falls prior to the mixing with sleet and freezing rain.  So 3 to 6 inches of snow region wide is a fair bet at this time… with even higher amounts possible in the northern Hudson Valley and Catskills.

As always… we’ll be tracking this closely as we move through the next 48 hours.  Check back for updates frequently!

The setup for Sunday hasn’t changed a whole lot, so at the risk of sounding repetitive, let’s look at the situation…

The morning hours will be cloudy and cold… with temperatures in the upper 20s to low 30s.  A few scattered snow showers are likely, but nothing substantial… until we near the noon hour.  Wet snow is likely to develop near or shortly after noon.  It could accumulate a coating to an inch or so across the valley… even up to 2 inches in the northern valley.  But by mid to late afternoon (2 to 5pm), the snow likely changes to rain from south to north along the Hudson River Valley.  That should help travel conditions for anyone heading to a Super Bowl party around sunset.  We’ll have to monitor the situation, for temperatures… precipitation, and road conditions.

It will be a different story in the Catskills, as colder air will hold on for longer.  Wet snow is likely for much of the afternoon, and that wet snow could hold on even at some of the lower elevations of the western HV.  So an inch or two of wet snow is possible in the western HV… and as you go well up into the Catskills… 3 to 6 inches of snow is possible.

But as we near sunset… it looks as if there is a surge of warm air through all of our viewing area… and that could lead to a period of moderate rain for much of the viewing area… before things taper off near midnight.  This is the trickiest part of the forecast, because if the warm surge of air does not come… then snow and ice could be extended further south.  It’s unlikely… but possible, and so we’ll need to watch things VERY close on Sunday, to see how they develop.

Expect many updates on Facebook, as well as updates to the website in the 24 hour forecast and possibly some short blog updates.  No matter what, be sure to be alert to the conditions in your area on Sunday, and to anyone travelling, have a safe and happy Super Bowl experience.