First Alert Weather In-Depth: Beyond the 10-day

ROCHESTER, N.Y. (WHEC) — Currently across the United States, we have a general west to east flow as our ridge over the Western US has begun to retrograde toward the Pacific. There is little to no interaction between the lobe of the Polar Vortex and the Eastern US as a weak ridge has stuck its nose in between, and this has kept the bulk of the cold to our north. The ridge over the east and ridge retrograding towards the Pacific will be key players in the overall pattern locally over the next two weeks.

As we move forward the ridge, which has been persistent over the Western US, will settle over the Pacific. This will introduce troughing over the Western US and leave room for the ridge over the east to settle in locally. This will keep us on the overall milder side of things through the middle of next week. We will have a couple of days over the next week on the colder side, but generally milder weather is expected locally. After the middle of next week, things will change once again and favor colder weather as we head into March.

This change will begin over the western Pacific and near Japan. Stormy weather over Japan through the remainder of this week will intensify and move east towards the Aleutian Islands by early next week. This stormy activity will deepen and have an effect on the ridge over the Pacific. The deepening of stormy weather over the Aleutian Islands will respond by kicking the ridge over the Pacific back east and toward the Western US. This will in turn favor cross-polar flow into Canada and allow the jet stream to dig across the Eastern US. Obviously, after that, this will favor below normal temperatures across our region and open the door for snow once again. Speaking of snow, we do have an active weather pattern the next two weeks with a few storm chances ahead.

Our first storm chance comes Thursday and Friday of this week. A yellow alert has been issued in regards to this storm and for more information on the Yellow Alert visit the “Yellow Alert” article on our website. This storm will mainly be rain as we are on the milder side of things, but a changeover to sleet, freezing rain, and snow is expected as colder air moves in on the backside. Light snow and a trace of ice are possible, but the bigger story will be the chance for flooding locally. A snow depth of a liquid equivalent of around 2”, rain accumulations near an inch, and ice buildup on local waterways will create the recipe needed for some minor flooding along some of the local creeks. After this storm passes by, we do not have to wait to long for more unsettled weather across our region.

Our next chance for unsettled weather will come next Tuesday and Wednesday (Feb. 22 to Feb. 23). We talked about this timeframe the last update, and just like last update rain is mainly expected locally. Not much of a cold air pull from the north and without that, the storm track will be favored north of us. We may have a brief chance ahead of this storm for icing, but no major winter weather is expected. Especially with the main air for this storm being pulled in from the southern Pacific, rain is favored. However, our next chance for wintry weather will arrive at the end of next week (Feb. 25 to Feb. 26).

This storm is a bit more interesting for winter weather as this will come as the pattern is changing. This means a better pull of colder air from the north and favor a more southerly track. Ridging out West will cause the jet stream to dig over the East. The jet dynamics do favor an area of low pressure to move into the Ohio River Valley, but the question will be if it will be pushed south or run north of us. With a better surge of cold air, this has a higher potential for a southerly track. Winter is not over by any means locally, and we will continue to monitor the unsettled weather over the next week. Our next update will come on Sunday, Feb. 20.

Temperatures: Mild through the middle of next week before turning below average next weekend and into early March.

Precipitation: Above normal for the next two weeks.

Storm Chances:

Feb. 17 – Feb. 18: Low pressure generally slides over us with rain, over to a mix, and then to snow. Light snow and ice accumulations, but bigger storms will mean the potential for creek flooding.

Feb. 22 – Feb. 23: Likely a warmer system with rain. Less of a flood threat due to melted snowpack, but something to watch with how much rain may fall.

Feb. 25 – Feb. 26: Better chance for winter weather with a stronger surge of colder air, but a northern tracked storms till possible. Pattern will change toward cooler weather toward this time and afterward.