Major winter storm Thursday, models still uncertain on precise track

Fine tuning

It's amazing how far weather forecast models have come in the nearly 30 years I've been in the weather biz. The reality? There is still no one "magic bullet" model that we can count on to accurately predict precise storm tracks and effects.

Welcome to my weather world.

What we can say for sure is that a major winter storm is winding up and aiming for the Upper Midwest Thursday. What we can't say yet is where the precise storm track will end up. That may make a world of difference in how much snow falls in the Twin Cities. It's another reason we don't generally forecast snowfall totals more than 24 hours in advance of incoming winter storms.

Here's the early take on projected winter storm and blizzard warnings this morning from the Twin Cities National Weather Service. At this point we need to be prepared for a possible major winter storm/blizzard Thursday.

Storm track shifting east?

The overnight forecast model trends started to show a potential eastward shift of the low pressure center with this storm. Many forecast models had been tracking the surface low through Wisconsin, west of Milwaukee along a Madison-Green Bay track. That's a perfect track for heavy snow in the metro and points east into western Wisconsin.

Click on the map below to see yesterday's solution favoring a more westerly storm track.

The overnight runs from NOAA's North American Mesocscale (NAM) forecast runs showed a distinct eastward shift in the track of the surface low. This morning's NAM run (12Z) supports that shift, tracking the surface low over Chicago and further east into Lower Michigan.

That potential 80 mile eastward shift could mean a world of difference for snowfall totals in the Twin Cities metro on the western fringes of this storm.

It could literally be the difference between several inches of snow, and sunshine Thursday afternoon in the metro.

Here's a comparison of yesterday's Global Forecast System (GFS) report  (western track) and today's NAM's eastward shift .

Here's the National Weather Service initial storm solution based on yesterday's notion of a more westward track.

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Here's the GFS snowfall output based on last evening's (0Z) model run suggesting a good 3 to 6 inches across the metro.

Here's the NAM snowfall output based on this morning's (12Z) model run. Note the eastward shift and significant reduction in metro snowfall totals.

Here's one version of the NAM's digital snowfall output from late Tuesday  cranking out an 8.3 inches snowfall total at Minneapolis-St. Paul International Airport.

Here's another output that tally's 6 to 7 inches for MSP.

Here's the updated NAM forecast from this morning's (12Z) run, which drastically lowers snowfall totals to around 1 inch in the metro.

This morning's GFS run is staying the course with a more westward surface low track through Wisconsin.

If this morning's GFS run is right, the Twin Cities will be on the receiving end of  major winter storm conditions with potentially heavy snow and plenty of wind Thursday.

The bottom line? A major winter storm and potential blizzard is still on tap for much of eastern Iowa and Wisconsin Thursday, and may include the Twin Cities metro. The latest model trends show a potential eastward shift in the storm track. That could shift the heaviest snow east of the metro, and could literally be the difference between several inches of snow, and sunshine in the Twin Cities Thursday afternoon.

Stay tuned as we track the latest model runs today and tonight. There is still the potential for a major winter storm in the metro, but a few model trends show a possible shift to the east. It is still too early to say for certain which scenario will prevail. 

Meanwhile enjoy the beautiful weather and day #2 of our February Thaw today!