Wednesday, November 15, 2017

I'm Dreaming of a White.... Thanksgiving???

Static Cold Pattern NE Next Week
Graphics Credit: AccuWeather
Millions of Americans are getting ready to hit the road for the Thanksgiving holiday, with the day of and the days around Thanksgiving being someone of the busiest travel days of the year. However, this year mother nature will make this a little more complicated for many of us throughout the country, whether we're traveling on the ground or in the air.

If you're making your holiday travels or just heading home for Penn State's Thanksgiving break over the weekend (Saturday 11/18 or Sunday 11/19), you'll probably encounter the potent storm system that will be passing through the Midwest and Eastern U.S. This cold front will dump some rain and produce some thunderstorms in the western Great Lakes, lower Ohio Valley, and mid-Mississippi Valley throughout the day on Friday 11/17. As the rain spreads to the Northeast on Saturday, some freezing rain, sleet, or snow is possible in upstate New York and in parts of northern New England. Additionally, flight delays are possible on Saturday in Washington D.C., Philadelphia, New York City, and Boston due to this weather system. This rain, and some thunderstorms, will stretch from the Great Lakes to Louisiana in the Central U.S., possibly causing flight delays at Chicago O'Hare, Detroit, Cleveland, Cincinnati, Pittsburgh, and Louisville. However, once this cold front pushes off to the east and out of the country, much colder temperatures will filter in behind it.

Static Lake Effect Snow Sat to Mon V2
Graphics Credit: AccuWeather
After the mild and wet weather to end this week, progressively colder air will unleash rounds of lake-effect snow from the Upper Midwest to the interior Northeast throughout the week of Thanksgiving and cause travel delays. Once the cold front passes through, cold and strong northwesterly winds will blow over the relatively warm waters of the Great Lakes. This will most likely cause lake effect snow bands to form on the southeast portions of all the Great Lakes from Saturday night (11/18) to Monday (11/20). Lake effect snow is especially challenging to travel in since the areas of heaviest snow are often times hard to predict and random, leading to drivers not being able to avoid the whiteout conditions that could happen. With lake effect snow, travel conditions can range from blinding snow and the potential for temporary road closures to sunny over a span of a few miles.

Throughout the week of Thanksgiving, two major pushes, or waves, of cold air are expected to move into the eastern half of the U.S. With the second push of cold air, strong northwesterly winds are again expected to be present over the Great Lakes from Tuesday night (11/21) to Wednesday night (11/22). This will most likely cause some more lake effect snow to form as the cold air passes over the relatively warm water. However, there is still uncertainty as to the extent or intensity of that round of lake-effect snow, since we're still around a week out from these dates. Anyone driving through the higher terrain in West Virginia, western Maryland and western and northern Pennsylvania should expect locally blinding snow squalls and a quick accumulation on roads.

Graphics Credit: The Weather Channel
As for temperatures, they are projected to be around 5-10 degrees Fahrenheit below normal for this time of year during multiple days next week (Thanksgiving week) from the Midwest to the Northeast. To add to that, winds will be strong at times making it feel cooler than it actually is.

As a note: the west and northwest United States should expect to see round after round of showers and thunderstorms throughout the Thanksgiving Day week, which will most likely hinder travel and delay flights around those areas.  

More details will arise later in the week in regards to forecasts of the weather over the course of Thanksgiving week, however motorists and airline passengers should anticipate delays and be ready to adjust their travel plans during the week of Thanksgiving, depending on where they live. Have a Happy Thanksgiving!

Wednesday, November 1, 2017

Welcome Mr. November: Major Changes Are In Store

November weather picture: snow accumulation can be seen on some trees along with colorful leaves - Photo Credit: Aram Boghosian for The Boston Globe
The feel of the crisp fall air as you walk out the door. The time of year when the shorts and t-shirts are retired for the year and the sweatshirts and jackets need to be broken out of the bottom of your drawers. Fall foliage is at its peak with trees displaying their true beauty, and snow, yes, snow begins to enter the conversation.

What a wonderful time of year it is as we flip the calendars over to November in 2017. But November also marks a time of the year when weather conditions are highly variable depending on the weather pattern that's in place as we transition from fall to winter. It's not out of the questions that we could see snow, severe thunderstorms, tornadoes, and hurricanes all throughout the month of November. With all of these weather events possible, it makes predicting all of them increasingly challenging.

Graphic Credit: The Weather Channel
The first event that the majority of Americans will experience at some point during the month of November is measurable snow. This may excite the snow lovers out there, including myself, while to others it may make them want to start wishing it was summer again. As exemplified by the graphic above, historically over the past thirty years, by the end of November a little more than about half of the United States has seen its first snowfall that can be measured (defined as 0.1 inches or more). This region includes central Pennsylvania and State College, so don't be surprised to see a few snowflakes falling from the sky as you walk around campus and possibly a measurable amount of snow at some point in the next thirty days.

November also typically brings powerful and more intense low-pressure systems sweeping across the contiguous United States, producing strong and even damaging winds. This is due to increased temperature contrasts from north to south across the country, with warm air still over much of the south and cooler air pushing in from the north. November has a long history of producing these intense storms over the Midwest, where they're commonly referred to as the "Witches of November," sometimes causing downed trees and widespread power outages. We've already seen a couple of these this season, with one of them bringing heavy rain and wind to the northeast region this past weekend.

Graphic Credit: The Weather Channel
Coupled with these strong low-pressure systems and cold fronts is the increased risk for tornadoes in what some refer to as the "second tornado season." Unstable conditions can form at times throughout November bringing large hail and possible tornadoes to the Gulf Coast states where warm, moist air can still be found. Going back in history to 1992, the largest fall tornado outbreak occurred from November 21-23 where a total of 105 tornadoes touched down, killing 26 people.
Image result for hurricane kate
Hurricane Kate, which made landfall in Florida just days before Thanksgiving in 1985 - Photo Credit: NOAA
Even though the hurricane season is finally winding down, and tropical systems are exceedingly rare to see develop around this time of year, it has happened in the past. November averages about one named storm every two years in the Atlantic Ocean, and I would not be surprised to see the record-setting 2017 hurricane season produce one last named storm.

And finally, bringing these weather events closer to home in Pennsylvania, the lake-effect snow season begins to ramp up throughout the month of November. Waters are still relatively warm in the Great Lakes and as cold air masses move their way over the region throughout the month, they will pick up this moisture and dump it as snow to the east of the lakes, including over some regions of Pennsylvania. These lake-effect snow events can dump a considerable amount of snow and last for several days, so be on the lookout, especially in northwestern Pennsylvania, for these lake effect snow events to pop up.
So what do meteorologists think this November will be like? According to the latest forecast from The Weather Channel, as seen above, it appears that we may experience a slightly above average temperatures throughout the month here in Pennsylvania. And as for precipitation, we're starting off the month on the rainy side, with plenty of rain in the forecast for the next seven to even ten days here in State College.

Have a great November and be sure to keep up-to-date on the weather forecasts throughout this month of variable and unsettled weather!