The 15z ensemble members agree that some convection will fire along a boundary in central MN and eastern South Dakota this evening but there is some disagreement about how much. #mnwx #sdwx

Quite a bit of member agreement on initiation location in the 9z ensemble for severe weather later today in both reflectivity and UH tracks. #mnwx

15z ensemble output for this evening. Some spread in the models around initiation. #mnwx

It’s that day! Time to take a look at the HopWRF Time Machine to look back to the great Halloween Blizzard of 1991! Our simulations start mid-day on the 31st for our 3km inner nest. Watch as the storm swept in! #mnwx #HalloweenBlizzard 3km: hopwrf.hopkinsschools.org/ResearchWRF11/

Yes, there is a signal of potentially accumulating snow on Tuesday, but there are many details to be worked out. Here is the probability of 4” of snow throughout the day.

Heads-up! There is some potential for freezing rain overnight and early in the morning along the MN-IA border area. Be on the lookout in the morning for ice! #mnwx #iawx

Merry Christmas everyone! HopWRF is tracking the incoming snow today, here is the ensemble mean from the 15z ensemble of models. Drive carefully and we hope you have a great day! #ndwx #mnwx #sdwx

Are we there yet? No, not yet, maybe another couple inches of snow overnight, then it finally moves out. On the plus side, there won’t be a big rush of cold air behind this so salt and other road chemicals will help clear out roads pretty quickly once plowed.

We are closely monitoring the potential for a significant winter storm across the northern plains & upper Midwest mid-week. The following are from the 6Z GEFS, the 31-member ensemble of GFS. A probabilistic approach is needed this far out. Available at: HopWRF.info

Another tool available on our website at HopWRF.info is the dprog/dt tool. This lets you look at the past 12 runs of the GEFS to compare to current so you can see trends. In this case the probability of 4” of snow in the mid-week system approaching. #mnwx #wiwx #sdwx

To say some of these probabilities are wild would be an understatement. The 6Z GEFS has 90%+ probabilities of 18” of snow mid-week. This is going to be a complicated multi-phase system so stay current on the forecast, it will change, it’s supposed to! #mnwx #sdwx #wiwx

Looking at the ensemble this morning using the postage stamps you can see comparisons for both intensity of snow and the progression between individual members. Mean MSLP image shows the progress of the winds. Both images are for noon today. #sdwx #mnwx HopWRF.info

From the 12Z ensemble we look at the Aviation plumes. Here we can see across the region from RWF, to MSP, to EAU when the visibility dives due to snow starting and when the winds pick up. It will be a challenging late afternoon and evening! #mnwx #wiwx

Weather observers needed across Minnesota and Wisconsin - Join CoCoRaHS, Please Retweet! If you're in a rural area your observation would be really helpful, but additional observations are also welcome in more populated areas. weather.gov/mpx/2023cocora…

You may have noticed, but the MPAS is temporarily off-line as we are utilizing that compute power for some reanalysis purposes for a presentation on the 25th Anniversary of the March 29, 1998 event at the Central Iowa NWA conference! We hope to see you there! #mnwx #iawx

Overnight snow could accumulate to a couple/few inches in part of northern Nebraska & northern Iowa overnight, looking to wrap up by 6-7am per the 3Z ensemble. #iawx #newx HopWRF.info

Headed to OSH or ready to head home? Check out the Aviation plumes! Located at HopWRF.info #OSH23

The HopWRF Ensemble model forecasts will be offline as we update software on our servers. We hope to restore the forecasts by this afternoon.

Some areas of low visibility are definitely possible tonight, please drive safely! Animation is probability of visibility less than a half mile. #mnwx #newx #sdwx #iawx

A reminder that we have point forecast plumes for OSH if you are headed that way! hopwrf.hopkinsschools.org/HopWRF-e-plume… #OSH25 #Oshkosh2025 #AviationWeather