AN OBSERVATION -
Never have I seen so many Winter Outlooks on the Net as I have seen this fall - and never have so many of them been so dire. Dire meaning; calling for a brutally cold and/or stormy winter across the Great Lakes and subsequent surrounding areas. It seems everyone and their mother are doing Winter Outlooks - whether qualified or not (educated and experienced). I must say; when I started doing Season Outlooks for Southeast Lower Michigan while employed by the National Weather Service some 27 years ago (The Super El Nino of 1997-98), I was in barren territory. The only other creators of Outlooks that I saw were the NWS Climate Prediction Center for the whole country and maybe a scant few private companies. A few surrounding WSFO meteorologists starting joining me in Weather Outlooks in the late 90s - early 2000s in the Great Lakes Region as "Down-scaling" got underway. Down-scaling involved looking at familiar hemispheric patterns known at the time; researched by meteorologists and climatologists nationally then, subsequently studying smaller climate and local patterns and making a winter forecast.
FORMAT -
A new format? I've decided to split up my outlook to get my Winter Analogues out first /Part - 1/; then discuss how the hemispheric patterns should affect the up-coming Winter 2025-26 pattern /Part -2/. Finally; expected winter weather forecast discussed and final forecast issued after Thanksgiving. Basically, this will be during the month of November before the climatological winter period of December - February with snowfall projections for entire snowfall season into climatological spring.
WINTER 2025 - 26 ANALOGUES
This new set of analogues goes back to the mid 20th century. Gone for this run are the earlier analogues (pre-1940s) as many were during cold periods with lower actual temperature data and normals. Over the past several decades (mainly since the 1980s); average normals have risen about a degree and a half with time when combining the recent climatological warming period along with urban climate warming at Detroit /DTW Airport/. For example; the winter normal average temperature is now 28.3 degrees for the 30 year period from 1991-2020. The 100 year temperature average /1891-1990/ before that time by my estimation was about 26.9 degrees. That leaves approximated departure of around a degree and a half /+1.4/ and this average is also included in the analogue data.
Leaving out the "colder period" analogues pre-1940 made little difference in this winter's sample as the temperature analogues since those analogues averaged notably below normal anyway. Snowfalls meanwhile varied considerably and really are a factor of prevailing storm tracks. Snowfalls varied from 18.0" /1960-61/ to a whopping 94.9" during the relatively recent cold and snowy winter of 2013-14. Maybe it's not surprising the "average" snowfall for the entire set landed just a shade (of snowfall) above the 45.0"norm at 45.6". Overall; snowfall norms have been rising slowly the past several decades from the mid-upper 30s to the mid 40s. You wouldn't know that the past three winters with the below average snowfalls officially at Detroit /DTW/.
Another thing I noticed back in the data from the Winter of 2013-14 Analogues compared thus far this November. When
normal to below normal November temperatures dominated in the analogues; the winter temperature was below normal.
Next up: Hemispheric Patterns & Meteorological Set Up
Bill Deedler -SEMI_WeatherHistorian
