Month: February 2023

Last Wednesday, February 22, 2023 I suggest there would be three significant storm between the 23rd of February and the end of this this current week. As it turns out, 5 days later the story as not changed at all. Clearly we got the storm on the 23th. That was a major ice storm from Kalamazoo to Jackson and as far north as Lansing. Below are the precipitation totals for that storm, snowfall totals and the ice accumulations.

Today we are currently getting the second storm I suggested would happen on the 27th. This has brought between a half inch and one and one half inches of precipitation to large area of Southwest Michigan. The has been 2 to 5 inches of snow from Mount Pleasant northward too.

Below are the maps for precipitation, snowfall and ice accumulation for today, as of 2 pm.

As for the storm I suggested would occur late this week, that still looks to be on track too.

The (thanks to Pivotal Weather) chart below shows the 24 hour total snow forecast from both the GFS (left) and ECMWF (right) between Friday at 7 am and Saturday and 7 am. It should be noted that the GFS has been very consistent with the track and snowfall over the past 5 days, while the ECMWF has had this storm tracking to our south. Only that last 24 hours has the ECMWF has the snow reaching our area.

The thing for us to watch with this storm is, will the models keep tracking it farther north over time? If so this too may be just another rain, sleet and ice event for us. Nonetheless this storm as the potion to bring significant impact to Southwest Michigan.

The map below (from Tropical Tidbits) shows the total ensemble mean precipitation expected over the next 2 weeks. Note the expected precipitation is in the 3 to 4 inch range over all of Michigan with the heaviest amounts over Southwest Michigan. It should be noted that while I am showing the GEFS forecast the ECMWF looks very similar for this time period.

We currently have an upper air pattern that features a western United States upper trough and eastern United States upper ridge. The map below shows this very nicely. This shows a large storm system at upper levels over the western United States and large upper high over the Gulf and eastern Atlantic south of Florida. You may note too the polar jet, which is where the cold air is locked, is over central Canada. It is the southern stream jet that is bringing the moisture for our storm today.

The problem for us is that that deep western trough does not get kicked out with today’s storm. That means we will see more systems come out of this through. As you can see on the side below, the system that comes out today does not really flatten the upper ridge to our east. However the deep system over the western United States does finally start to move east, but in parts. The first part comes out early next week, with a negative tilt upper wave. That storm could be as wet or even wetter than what we have today. Then if that is not enough, yet a third system seems likely when the western upper trough finally moves out late next week.

The bottom line is expect a stormy end to February and a storm beginning to March.

Based on the information below I would suggest we have already started an early spring weather pattern. Based on the chart below, this has been to date, the 8th warmest winter on record in Grand Rapids, with only 7 more days remaining February, this will not change significantly.

I want to point out that I am not saying we will not get more snow, or even a period of cold weather, what I am saying it warmer than normal period will be longer than colder than normal periods and any snow we do get will melt within a few days.

One of the nice things about this format is, unlike when I use to write forecast discussions from the National Weather Service, I can add images now!

I am expecting any mixed precipitation that develops this morning over our area to change to snow by afternoon. It will become windy this afternoon and temperatures are expected to fall into the 20s to mid to late afternoon. This will lead to slippy travel over most of our area during the afternoon and evening. The snow should end shortly after midnight.

The heaviest snowfall amounts of 5 to 8 inches will be north of I-96 but south of route 10. The I-96 areas is expected to get between 2 and 4 inches by this evening.

This image is thanks to the Grand Rapids National Weather Service

FOR SOUTHWEST LOWER MICHIGAN

Note the heaviest snowfall this winter has been displaced inland toward US-131 compared to the typical heaviest snowfall near the lake shore (see map below). What is odd too, is my Grandville weather station has less total snowfall than the official site at Grand Rapids. I do not remember a year, since I moved here in 1995 where that was true like it is this winter.

This is the normal seasonal snowfall across the area.

The percent of the mean shows this too, that is the heavier snowfall, relative to normal has been displaced inland for this winter season.

This map above is what typically happens in February when January at Grand Rapids had a very high frequency of above normal temperature days. This suggest we will be near the storm track and that warmer than normal temperatures appear more likely than below normal temperatures for Southwest Michigan.

What I did to figure this out was to look at all the daily departures from normal in the January’s in the Grand Rapids climate data base. For each January I counted the number of days with the daily departure from normal being positive. This used the NCEI normal for that decade. As it turns out, of those January’s with the frequency of being warm than normal was in the top 1/3 highest, 24 years, only 3 years 1900, 1914, and 1934 had a February with the departure from normal frequency in the top 1/3 coldest.

Based on just this idea, it would seem February in Grand Rapids will more likely end up with a higher frequency of above normal temperature days than below normal temperature days. More more point, there is a strong correlation for high frequencies of above normal temperature days in a calendar month and warmer than normal month.

Now let us look at the latest CPC forecast data to see if there is any chance this could really turn out this way.

The CFSv2 forecast for February (the last one CPC issued) surely looks like my forecast map above. Note how the warmer than normal is over the eastern and central CONUS and colder than normal is over the western states. I do admit there is a larger area of warmer than normal on this forecast map than on my forecast map.

The above map is CFSv2 temperature anomaly forecast for February 2023 from the 18z run on the 31st of January.

This is the 500 Mb forecast height anomalies for February

Now lets look at the very latest (Feb. 4th) CFSv2 latest weekly forecast. First we will look at the upper level height forecast. This suggests we have an upper level ridge this coming week, which will keep us warm. However for the rest of the month it would seem and upper trough develops and persists into March. This would mean cold will win by the end of the month.

This developing upper trough does not really bring us cold weather until the end of the month. Looking at the next four weeks, it would seem my forecast, based on the frequency of above normal temperature days at Grand Rapids may have predictive value across the CONUS!

Does the MJO support this idea?, I do believe it does. The forecast below is from the ECMWF (which tends to do better than the GFS version of MJO), in this case through they are similar.

Phase 3 is cold for SW Michigan but phases 4 through 7 are warm for Michigan in February. We do not see the MJO going into phase 8 , which is cold for SW Michigan until the end of the month. This will be fun to watch and see how this plays out!