2023 12/19

SWMI AMS/NWA Chapter Meeting Minutes

Tuesday, December 19th 2023

West Michigan Aviation Academy 

5363 44th St., Grand Rapids, MI 49512

Officers Present: Alana Dachtler, Aubrey Papke, Linda Paige, Warren Wheeler, Andy Schut

Attendance: Bill DeVries, Craig Woods, Kreigh Tomaszewk, Tom Oosterbaan, Jim Carptener, Bill Marino

Call to order: 7:06

Winter Forecast 2023-2024 by Bill Marino 

President Alana Dachtler calls the meeting to order and addresses that Linda Paige will post the winter forecast results tomorrow. She then turns the meeting over to Bill.

Bill tells us that it is an El Niño this year meaning a warming of the ocean surface, or above-average sea surface temperatures, in the central and eastern tropical Pacific Ocean.

Bill describes that he will talk about the winter last year compared to this year, the warmer oceans, and what might impact our winter weather this year.

Last year was close to a classic La Niña. Precipitation was going to dry along the west and wet along the north. The heaviest snowfall was farther inland which is unusual and last year was the 4th time we have had a La Niña 3 consecutive years in a row. Bill's predictions were very close last year. 

Our sea surface temperatures have been above normal, especially in the past few weeks. Strong El Niño. By summer it will start to go into a La Niña. 

CPC expects warm and dry are most likely outcomes for northern areas while near normal temperatures and wetter than normal conditions in the southern regions.  The precipitation trend is mostly wetter and much wetter trend over the southeastern states. 

Over half of the 29 El Niño winters since 1940 have had above-average temperatures across our area. Over half of the 29 El Niño winters since 1940 have had below precipitation and snowfall in our area. 

Snowfall will be heaviest over the central CONUS and northeast and the western mountains. The only major change during the second half is the winter there tends to be less snowfall over the eastern Great Lakes and is snowier over the Rockies. 

We have a record warm ocean temperature, the greatest temperature anomalies are on the Pacific side of South America in November and now in December the warmest waters are in our El Niño regions which are more to the west. 

Average sea surface temperatures around the world have changed from 1901 to 2020 by 2-2.5 degrees which is significant. 

How does having warmer waters cause an issue in predicting the forecast? Well, Bill says that the contrasts in the gradients within an El Niño don't give good responses, a strong contrast between warm and cool waters. 

This year compared to 1982 has barely any cool water, especially in the poles. 

Convention this year falls farther west over the equator which changes the jet stream response. 

The lack of contrast could be a problem for establishing a strongly dominant southern stream jet this winter. We would have a much higher risk of polar outbreaks this year.  

QBO - quasi-biennial oscillation direction of the wind at like 200 millibars over the tropics, if the wind is westerly it goes with the prevailing wind but if that wins over the tropics is easterly it creates a wind that creates a very rare block, and that is occurring this year and that creates a problem. QBO is going negative currently which leads to a fair amount of blocking. The most notable difference is the stringer northern branch feeding into western Canada and diving into the Great Lakes when the QBO is negative. El Niño, negative QBO you shouldn't expect periods of very warm or very cold weather. The negative phase brings colder air farther south over the Great Lakes into New England over the QBO phase on surface temperatures. During a weak El Niño, you typically see weak easterly winds over the tropics. The impact of QBO on our forecast is when the QBO is easterly during the winter, it shifts warmer than the normal area to the northwest, and the expanse is cooler than normal over the eastern CONUS. Decreases the area above normal precipitation over the southern CONUS but has little impact on the precipitation anomaly on the northern CONUS. 

Snowfall through the end of January  

December = warm 

January = turns cold 

February = still cold 

For most of West Michigan snowfall is expected to be around 10 inches below normal for the season.

CONCLUSION:

-The winter of 2023-2024 is expected to be one of those strong El Nino Winters.

-However, the unusually warm sea surface temperatures over the Pacific Ocean (north and south Pacific) in combination with the negative phase of the QBO will cause this winter to have more extreme weather events than would be expected in a typical El Niño.

-The area of the CONUS that averages above normal is expected to be farther north and west than a typical strong El Niño. The area below normal temperatures should also be farther north than in a typical event. 

-The area of heavy precipitation is expected to be over the southern CONUS and California, which is typical. 

-For Southwest Michigan, I expect a more typical winter with periods of extreme cold, and also periods of well above normal temperatures that will likely result in an average winter temperature close to normal. Precipitation and snowfall should be below normal due to a farther  south storm track than in a typical winter 

Bill concluded his presentation at 7:53 and opened up to questions from the group

Meeting adjourned at 8:17