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.

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.

November 2017 temperature outlook: Colder than average in the Northwest; Warmer than average in the South: https://t.co/i11g4I2kil pic.twitter.com/amrYprMu6n

— The Weather Channel (@weatherchannel) November 2, 2017

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!