First Alert Weather In-Depth: Looking out for Rochester

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ROCHESTER, N.Y. (WHEC) — It’s another Wednesday in the winter which means another update for “Looking Out for Rochester.” Currently, the jet stream is entering North America just to the north of Seattle, WA. It is moving a tad northeast before digging into the Tennessee River Valley. It is then moving towards the northeast along the I-95 corridor and then aimlessly out to sea. Generally a non-threatening jet stream, especially with the continued lack of blocking across the Northern Hemisphere. One thing to note is that we have just missed out on a big Winter storm across the Northeast as our light snow today will blow up for folks in Newfoundland and Nova Scotia in Canada. The reason… no blocking. We have been mentioning this so much over the last two weeks but that is a large reason as to why things have been so quiet locally and across the eastern half of the U.S. However, changes may be on the horizon.

That “horizon” is still a bit of time away, unfortunately. We will have to get through a warm period across the Eastern US before we talk about potential changes. The warm period will begin with a “bang” with another strong area of low pressure that is expected to cut through the Great Lakes this Saturday and bring us mild temperatures, scattered showers, and once again gusty winds. Again, upper-level support is suggesting winds near 50 mph for localized areas through the day Saturday. The gusty winds are thanks to another large temperature gradient as temperatures Saturday may reach the 60s, and then drop into the 30s for a brief time Sunday. For more information on our strong gusty wind threat, head back to the weather page for continued updates and information about a potential “Yellow Alert.” After this storm passes, things turn much warmer into next week.

Yes, we have a brief cool down ahead for this Sunday, but behind this system, the southeast ridge will build and build quickly. This upper-level ridge will allow our temperatures to turn well above average. High temperatures next week will spend most of their time in the 50s with the opportunity to hit 60 degrees late in the week. Not only will we be on the mild side of things, but we will also be on the quiet side of things. This upper-level ridge will be strong, and it will push the jet stream well to our north and keep the storm track well to our north. This means the warmth next week will be greeted with plenty of sunshine so definitely enjoy it even if you want snow to fall. Although I am a big winter fan, I will definitely be enjoying the mild and calm week ahead. While we will be soaking in the sun and basking in the warmth, the atmosphere will continue to be at work with some interesting features beginning to pop up which may signal a pattern change towards more sustained Winter weather. While warm weather will be in place locally through the majority of next week, features in the atmosphere that signal blocking will begin to pop up.

Troughing has been a common occurrence over Alaska for a long time now, but models are signaling a change to that next week. Models are signaling an upper-level ridge building near Alaska which is good news for Winter. This is the “Eastern Pacific Oscillation” that we have been talking about which has been in the positive phase for some time now. This ridging would push it into the negative phase which is important because a ridge over Alaska will squeeze all that cold air southward towards the Continental US. Not only will the cold air get squeezed southward, but this opens the door for the jet stream to dig more than it has and interact with the sub-tropical jet stream over the southeast US. Another interesting feature that will has been popping up is potential ridging over Greenland. Models are also signaling for ridging over Greenland to build towards the end of next week and into the following week. This is the North American Oscillation and a key player in East Coast snowstorms. The ridging over Greenland will help force the jet stream along the East Coast and open up the door for large storms to form closer to our coast and increase the chances for cold air to remain in the Northeast. These are all interesting features to monitor over the next week or so, but there is a wrinkle to the whole thing as of now. That wrinkle is troughing over the Western US. This troughing over the Western US would ruin the potential winter pattern across the Eastern US as it will increase the odds for the Southeast ridge to sustain. What we would need is this troughing to retreat into Canada and help force the cold air into the Central US and eventually into our region locally. The retreating trough would also allow the ridging over Alaska to move a bit more eastward and really get things going locally. All this talk about a pattern switch is nice, but we would need something to kick start that change and there are signs for that next weekend.

After a mild and calm week, next weekend is where we will be keeping our eyes on an area of low pressure to move into our region. We are not worried about snow with this system as there will be too much mild air in place, but we will be watching out for this system to be a change toward some sustained winter weather. This storm will likely once again feature showers and wind, how strong is still uncertain, but behind this system, things may turn interesting. This system may bring in colder air and change the orientation of the jet stream if the aforementioned pieces fall where they need to be. If these pieces do fall where they need to be then the following Wednesday may become one to watch. That Wednesday, Dec. 22, is our real next chance for winter weather across the Northeast. Models are signaling the jet stream to become active over the Ohio River Valley, which will allow low pressure to form, and potentially move towards the East Coast. The track remains uncertain as we are two weeks away, but this is our next legit chance for some winter weather, and if the pieces fall where they need to be then we should be in good shape. Our next update will come on Sunday, Dec. 12, fingers crossed these trends continue.

Temperatures: Turning above normal this weekend and through next week (Dec. 11 – Dec. 18) before turning seasonable into Christmas week (Dec. 19 – Dec. 22)

Precipitation: Wet on Saturday before turning dry next week (Dec. 11 – Dec. 17). Things become more active next weekend and into the following week (Dec. 18 – Dec. 22)

Storm Chances:

Dec. 11: Great Lakes Cutter. Rain and wind will be the main story. Gusts over 40 mph are once again possible. Stay tuned for a potential “Yellow Alert.”

Dec. 18: Scattered rain showers likely with a cold front, wind? Potential pattern switch behind the front.

Dec. 22: Low pressure in Ohio River Valley? The door opens once again for winter weather if pieces fall where they need to be.