A lot of us want to FORGET what happened last winter… I know I do! A lot of forecasts (including ours) were on the same page, as there were strong signals for big potential winter storms and cold. However, it was the exact opposite. Washington, D.C. saw one of their “snowless” winters in recorded history – but it wasn’t just D.C. – a lot of “green” was a very common sight across much of the Mid-Atlantic and Northeast.
So, the question everyone is asking: Even with La Nina conditions developing, which normally favors warmer conditions across the Southeast, does that mean another snowless winter? NOT necessarily. I’ll explain why later on in this post. For now, let’s jump ahead to FALL, because it’s OFFICIALLY here (September 22nd!)
Looking at the upper air pattern, it continues to show a trough in the Eastern United States with a ridge of high pressure across the Western U.S. This translates to cooler temperatures in the Eastern U.S. with warmer conditions continuing in the west through at least mid October. There will be a few days “in between” cooler shots of air where temperatures will likely reach 80 degrees east of the Blue Ridge. With these shots of cooler air, another frost across the Shenandoah Valley and Virginia Piedmont is definitely on the table within the next week or two.
Additionally, we are also seeing a return to stronger blocking over the northern latitudes of Greenland and the North Atlantic. This blocking would keep a trough of cooler and unsettled weather across the Eastern U.S. and if the timing is right, we could see tropical systems interact with fronts that dive in from the Northwest into the Eastern U.S., which could help enhance our rainfall. We’ll need to watch for any tropical activity from now through at least mid-October as this would lead to flooding and flash flooding.
Also, this transient blocking over the Northern Hemisphere will bring about a robust start to the snow season over Siberia and Russia for October. This is ONE ingredient if you want snow, as this helps to send cold waves of air into the Central and Eastern U.S.
The “Fall Foliage Peak” May Arrive EARLY Across The Mountains!
The cooler temperatures and recent rainfall plays a HUGE role when it comes to fall foliage. Many of our past summers into early Autumn seasons have been very warm and dry. However, that is not the case this year!
This will be the first time in several years that we’ll experience beautiful and vibrant colors! Across the Allegheny and Appalachians, we could start reaching the “peak” as early as the first week of October across the highest elevations. We’re thinking closer to the second week in October across the Blue Ridge Mountains and the Virginia Highlands, mid to late October across the Piedmont, and closer to Halloween along the coast.
Does A Cool Fall Mean A Warm Winter?
I’m sure you’ve heard the old saying “A cool and damp fall leads to a “warm winter.” Well, it’s NOT exactly true. It doesn’t mean the next season is going to be the total opposite. We’ve had many summers that were cool and wet and still had snowy winters. We’ve also had cool and wet Fall seasons and big winter storms come winter. I am also sure you heard the saying “If it’s warm, it can’t snow.” That depends on how you look at it. If you are going by the temperature, yes – however, just because a winter outlook is “warm” doesn’t mean you won’t see snow or colder temperatures.
Looking back at the last TEN winters, we have averaged ABOVE NORMAL temperatures. While the average may be above in the temperature department, we have squeaked out many snow and ice events. One example is the “Godzilla El Nino” during the 2015-16 winter. We had ONE snow event in January 2016 that was a blockbuster event and all the teleconnections and analogs supported a big snow. We measured FEET of snow across Northern Virginia, portions of Maryland, extending into Pennsylvania and New Jersey! Once that ended, we flipped the switch to warmer temperatures and the rest of the winter remained very warm. We’ve also had our share of decent snows in 2013-14, where it was a big winter in 2013-14 across the Northern Virginia area.
Our upcoming winter season will be influenced by La Nina, with that pesky Southeast Ridge, which can make long-range forecasting very difficult. You can always “assume” in a La Nina winter that the Southeast Ridge is going to dominate the temperatures, but there are many other factors to where you CAN get decent snowfalls in the Mid-Atlantic. If we were to go by the “Typical” La Nina setup, this would favor warmer and drier conditions across the Southeast and cooler and wetter conditions to the north. We have picked analogs that have either matched sea-surface temperatures or were weak or moderate La Nina years. I don’t think we will be ‘as toasty’ like we were last winter, but we will likely experience many “mild spells” with shots of colder air that lasts a few days, before warming right back up.
The Jetstream will also dive in from the Pacific Northwest into the Rockies, before taking either a ‘northerly’ track into the Great Lakes Region, which means a surge of milder air across the Eastern United States, OR a track that’s closer to the Ohio River Valley. While that would still mean an overall warm setup for us, it’s important to note that IF we see any of these strong troughs (like we’re seeing now) this winter, we can still EASILY get to “normal” snowfall. It’s nearly impossible to forecast in the long range when it comes to the NAO (North Atlantic Oscillation) – or “Greenland Blocking” that helps us in the snowfall department, since it’s more of a shorter term teleconnection.
Final thoughts (for now): While our “preliminary” temperature forecast this winter calls for “milder” conditions, that doesn’t mean it won’t snow. Usually in La Nina setups, it’s hard to get coastal lows across the southeast due to the ridging in place. However, with many fronts and low pressure systems across the Pacific Northwest, diving into the Rockies, a few of these systems will likely sneak as far south into the Tennessee River Valley and move into the Mid-Atlantic. While I believe that many areas will see BELOW AVERAGE SNOWFALL, it DOES NOT mean it won’t snow and it only takes one or two snow events to reach your averages in Virginia. Also, if our cooler Fall pattern does indeed extend into winter, OR relaxes and returns for a bit in the winter, then the possibility of “average snowfall” is on the table.