Wednesday, February 28, 2018

March Comes in Like a Lion: Strong Late-Week Nor'easter Incoming

Static Nor'easter 3 pm
Very strong winds and a mixture of snow and rain will blanket the northeast later this week. Credit: AccuWeather

It may feel as if spring has already arrived here in central Pennsylvania. We've experienced several days throughout the second half of February with temperatures over the 60-degree mark, even with a couple of record-setting days last week when we reached over 70 degrees! Shorts and t-shirts have been broken out and students are out playing frisbee and football on the HUB Lawn. Even with the copious amounts of rain throughout the second half of February (we actually broke our record for rainfall for the month of February here in State College), I'm sure many people have enjoyed the recent warmer temperatures after a frigid start to the winter. As seen in the graphic below, temperatures over the past seven days have been eight to twenty degrees above average throughout the northeast! So much for the groundhog's prediction of six more weeks of winter...

Temperatures have been well above average throughout the last 7 days of February. Credit: High Plains Regional Climate Center.

...but not so fast. Winter has not had its last laugh just yet. A strong nor'easter is expected to impact the northeast from Thursday through Saturday this week with strong winds, coastal flooding, heavy rain, and areas of heavy snow all expected. This will be a very complex system, to say the least.

For central Pennsylvania, where students will be having their last couple days of classes before spring break begins, this will be a mostly rain and wind event with a few snow showers possibly mixing in on Friday. The rain will move into our area around midday on Thursday and at some points throughout the afternoon and into the evening, it could be moderate to heavy rain. The rain will taper off by around midnight on Thursday night with winds then shifting to be out of the northwest, ushering in colder air and the possibility for a few snow showers throughout central and western Pennsylvania.

However, the impacts from this system will be much worse throughout New York state, across New England, and especially along the Atlantic coastline. When the center of low pressure moves off of the coast of New England, very strong winds will be blowing directly on-shore (especially in Eastern Massachusetts, Cape Cod, and Southern Maine) pushing the ocean water on-shore and causing coastal flooding and beach erosion. As seen in the graphic below, wind gusts could reach up to 80 miles per hour in some locations due to the strengthening of this nor'easter off the coast. To make matters even worse, a full moon occurs on Thursday night which increases the height of the tides, further contributing to the coastal flooding that is bound to happen. These high winds will also most likely be to blame for many airport delays throughout the northeast over the next few days, as well as causing many power outages to occur.

Static NE Storm Winds
Peak wind gust forecast for Thursday night through Friday night causing many impacts. Credit: Accuweather


Not only do we have to worry about the winds and the coastal flooding, but keeping track of where the snow will fall is also vitally important. Due to the intensity of this system, it will usher in enough cold air from Canada in order to change the rain over to heavy, wet snow in some places. The places that will see the most snow are the Catskills of New York as well as the western part of New York and far northeastern Pennsylvania. The majority of this snow will fall throughout the day on Friday, causing many traffic headaches for anyone traveling to the north or east of State College. 

Static Snowfall Map 3 pm
AccuWeather's snowfall forecast - this will change depending on which model you wish to believe. Credit: AccuWeather

After this strong and complex system moves out of the area, temperatures are going to turn much cooler than they have been. NOAA's Climate Prediction Center forecasts temperatures to be around average to slightly below average as we move throughout the first half of March. This means temperatures sticking around the low to mid-40s for highs and mid to upper 20s for lows (a far cry from the 60s and 70s we saw in the second half of February).

Colder and more seasonable temperatures are expected to return as we move through the beginning of March. Credit: Pivotal Weather

If you want more details on this storm system and how the weekend is expected to be, check out my Centre County Report forecast video from Wednesday morning: 


Wednesday, February 14, 2018

We've Got a Very Interesting Situation on Our Hands...

As I was sitting in the Weather Center on the sixth floor of the Walker Building on Tuesday afternoon as I usually do, some intriguing and exciting news was being talked about. We might get a snowstorm this weekend. Yes, you heard that correctly. I know, it caught most of us meteorologists off guard too. All of a sudden the European model showed a large swath of snow moving over Pennsylvania Saturday evening and throughout Saturday night in its latest run. If you went back to the previous model run, nothing.

The European Model showing moderate snow over the Northeast throughout Saturday night. Credit: weather.us

Very strange, but interesting at the same time. As good meteorologists, we don't rely just on one model but instead we look at a variety of different models to ensure that there's some consensus. And sure enough, a few other models, like the Canadian and the North American Models, were showing this same area of snow moving its way through the Commonwealth and the Northeast Saturday night. However, others, such as the GFS, were predicting that the storm would track south of Pennsylvania, leaving us dry and clear for the weekend.

The GFS model showing the area of rain moving south of Pennsylvania and the Northeast. Credit: Tropical Tidbits

I think that this is incredible and a testament to the fact that our weather changes very rapidly. Having a situation that varies slightly at the beginning can drastically change the outcome. That's basically the entire concept of numerical weather prediction. Varying the initial conditions ever so slightly, but over time those small variations create large differences in the end result. When you average all of these varying results together you can get a pretty accurate forecast.

The fact of the matter is that this system practically came out of the blue. Forecasts were calling for a beautiful weekend filled with sunshine and no chance of precipitation as recently as Tuesday morning. Heck, I even flat out said it was going to be a gorgeous weekend in my video for the Campus Weather Service on Tuesday morning. Then as we went throughout the day on Tuesday, the possibility of getting snow on Saturday night was increasing by the hour. By the end of the day the National Weather Service and other general forecasting websites, such as Accuweather and The Weather Channel, were hinting at the possibility of some snow this weekend.

Saturday Night's Forecast
The Weather Channel's forecast for Saturday night for the Northeast. Credit: The Weather Channel

There are a few major reasons why it's so important to monitor this storm for this weekend. First, since it's THON Weekend here at Penn State, students and visitors will be traveling both from near and far to the Bryce Jordan Center throughout the weekend. Any accumulating snow will create a lot of headaches and traffic delays for everyone trying to make it to State College for this much anticipated weekend. Secondly, it's also President's Weekend which means that a lot of people will be traveling on the roads and highways throughout this weekend, especially in the Northeast to go skiing. If this system dumps some snow throughout the Northeast, people who were planning on traveling on Saturday night or Sunday morning might have a hard time doing so with snow covered roads and highways.

In other words, if this snowstorm actually happens, the timing could not have been worse and the impacts will surely be felt from Pennsylvania up to Maine. This is, unfortunately, one of those "wait and see" kind of storms, where we won't know the exact track and impacts from the storm until one or two days ahead of time.

Northeast Storm Scenarios 5 am Wed static
AccuWeather's two scenarios of the track of the storm. Either way, this is not shaping up to be a blockbuster storm - accumulations should only be a few inches. Credit: AccuWeather

BONUS: You enjoying the warm temperatures? Good news. They're going to stick around for a little while. We will reach close to 60 degrees today and then we will have a couple of other chances to reach the 60-degree mark next week. However, keep your umbrellas and rain jackets handy because these mild temperatures are going to bring with them plenty of rain opportunities.

The Climate Prediction Center's temperature forecast for the middle to end of February. Credit: The Weather Channel

NOAA's Climate Prediction Center's forecast is fairly confident that the entire eastern half of the country will experience above-average temperatures as we move through the next ten days. But what's next? Early long-range forecasts for the beginning of March are indicating a cooler than average start to the third month of the year, but we'll have to wait and see. This year might be shaping up to be a repeat of last winter: mild and wet February followed by a cold and snowy March.

Wednesday, February 7, 2018

Well That Was an Interesting Storm... My Opinion on Penn State's Decisions

There was a noticeable buzz in Weather Center on the sixth floor of the Walker Building Tuesday evening. Whether you want to call us weather weenies or sky nerds, we were getting excited about the winter storm that was going to impact the Northeast during the day on Wednesday. Many of us comparing five different weather models fascinated by what the snowfall rates could be, others trying to predict what the snow totals were going to be for State College, and some placing bets on if Penn State would cancel classes.

In my opinion, this was the type of storm that's the hardest for meteorologists to predict. Winter weather is hard enough - everyone wants to know exactly how much snow they'll get. Let me tell you something. It's not that simple. If a heavier snow band happens to develop directly over a specific area, they'll probably see a localized accumulation that's much more than the surrounding areas.

And if you add warm air (that's above freezing) to the mix, like we had in this situation, a million other scenarios arise. Who's going to see a mixed precipitation? Will it be freezing rain or sleet (yes, there is a difference)? When will specific areas transition from snow to ice to rain? How will this dampen snow totals? It's a forecaster's nightmare (but, still kind of fun since I love the weather).

How different temperatures at different layers of the atmosphere impact the precipitation type. Credit: Mesonet
We were left looking at atmospheric soundings at different forecast hours to see where in the upper atmosphere and when it would become above freezing and possibly transition over to freezing rain or sleet at that time. We were comparing old model runs to newer model runs to see if they were trending warmer or colder and trying to see when that warm nose would poke through and deliver us some frozen precipitation. What we did know was that this was going to be a heavy hitter. Snowfall rates from 5am to 10am were looking to be at or over one inch per hour and with temperatures near 32 degrees, snowflakes were going to be rather large, helping the snow to pile up quickly. But then, after transitioning over to sleet/freezing rain/rain, it was appearing that the system might be moving out of our area by 1 or 2 pm.

I definitely would not have wanted to be the Penn State staff in this situation. Whether you decide to cancel classes or not, people would have disagreed with your decision (it's like a politician - you can never please everyone). Tuesday night they decided to cancel classes until 10am. That was a step in the right direction, but I also thought that that was when the heavy snow would be transitioning over to sleet, causing a massive travel headache. Then, Wednesday morning I woke up to the (wonderful) sight that classes were canceled until 5pm. I was honestly shocked that the university did this, but I happily went back to bed.

When I went out for lunch around 1pm, there were only about 3 inches of snow on the ground, a light freezing rain falling from the sky, and some minor slush on the sidewalks. I do have to give props to OPP - they were out clearing all the sidewalks, and doing a good job with them as well. We did switch back over to snow for a few flurries, but the overall precipitation was less than anticipated. I honestly think that Penn State should have just canceled classes until 12 or 1 pm (I guess hindsight is 20/20). Especially hearing all the stories on Tuesday of how rarely Penn State cancels classes (that it takes upwards of a foot or two of snow before they've canceled in the past), I was shocked to hear their actual decision. I wonder if the day last year when they didn't cancel classes and people were slipping on ice all day had an impact on their decision...

BONUS: AccuWeather just released their Spring 2018 preliminary forecast, which puts Pennsylvania and the entire Northeast in the category of chilly temperatures and the possibility of more mixed rain and snow events. This forecast of a slow transition to mild weather is not a welcome sight for many of you warm weather lovers, but we'll have to wait and see how it actually plays out over the next several months.
2018 spring highlights
Credit: AccuWeather