Forecast model chaos theory: Rain or snow chance emerging next Tuesday?
Forecast models picking up on a potential weather system next week.
Minnesota weather and forecast models can change quickly in November.
The numerical forecast models we use everyday crank out various solutions for the next few days up to about two weeks. Usually, there’s a rhythm to the evolution of weather patterns. We can see pattern changes evolving. That gives us a sense of when a milder than average November — like this one — may evolve into a pattern that can produce wintry storms.
November forecast models can shift quickly, and pick up on a wave that’s just now coming into focus.
Weather chaos theory in motion.
Create a More Connected Minnesota
MPR News is your trusted resource for the news you need. With your support, MPR News brings accessible, courageous journalism and authentic conversation to everyone - free of paywalls and barriers. Your gift makes a difference.
Keep an eye on next Tuesday. The forecast models are picking up on a possible storm wave that has the potential to be just a minor rain or snowmaker. Or it could evolve into something more significant.
Ron Trenda did a good job laying out the weekend forecast a couple of hours ago. Check out his midday post if you’re looking for weekend forecast details. I’ll take time in this post to focus a little more on next Tuesday’s potential weather system.
The system
An upper air wave will plow into the Pacific Northwest by Monday. This system will likely spin up a low-pressure system across the Midwest by next Tuesday. There are currently big forecast model differences in how this system may evolve.
The Canadian model develops a moderate low-pressure system in Kansas with a mixed precipitation shield across Iowa next Tuesday.
The American GFS model develops a stronger system further north, and suggests a widespread mix of rain and snow across Minnesota Tuesday.
Snowfall potential?
This system looks potentially just cold enough for snow across parts of Minnesota Tuesday. But again, current forecast models differ on how much, and where.
We’re still 5 days away from this possible system. So here’s the usual caveat forecast warning label, don’t focus on precise snowfall totals here. I’m simply posting these as insight into the forecast process and potential solutions several days before a possible system.
The National Oceanic and Atmospheric Administration’s GFS model suggests a plowable snow event for a big chunk of the Upper Midwest.
The Canadian model suggests just a dusting in the Twin Cities with a couple of inches farther north.
Forecast uncertainty
Even after 30-plus years of almost daily weather forecasting, I still love the forecast process. My blood pumps a little faster when a new forecast model run comes in. Yes Minnesota, I’m a weather geek.
My process is to do my own forecast first, then check other sources like NOAA/NWS to see if I may have missed something, or if another weather expert has a different read.
My read today of the Twin Cities NWS Forecast Office forecast discussion confirms my level of uncertainty and watchfulness about next Tuesday’s potential system.
For those of you wanting exciting weather, perhaps your wishes will be granted next week. The GFS, ECMWF, and GEM all show a shortwave with an upstream, 150 knot north-northwesterly jetstreak arriving on the Pacific Coast Monday. This trough is forecast to move eastward into the Central US by Tuesday, amplifying while doing so as the upstream jetstreak digs into the base. A likely scenario with this kind of feature is strong cyclogenesis occurring somewhere over the central CONUS. However, while forecast models all attempt to develop a storm system Tuesday, large differences lie in the system`s origin location, strength, and eventual track. Forecast trends will need to be closely monitored to hopefully gain more confidence but, for now have slightly bumped up PoPs across southern MN Tuesday. Additionally, temperatures mid-next week would likely be influenced if a strong cyclone does indeed develop near our region.
Bottom line?
There will likely be some rain or snow next Tuesday across the Upper Midwest including Minnesota. But the system in question is literally just emerging from Asia into the western Pacific today.
There is still great uncertainty about how a possible system will evolve across the Upper Midwest next Tuesday.
Stay tuned.