A BIT OF A DOWNER...
A big old upper air low is sweeping through the Great Lakes bring a healthy shot of cold air to the Midwest. You can see the NW flow that's driving it in our direction.
Readings late Monday were near or below freezing.
Temperatures like that are a good 10-15 degrees below normal.
Wind chills were a bit of an issue too running in the range of 15-20 in the afternoon. Brisk to say the least.
One contributing factor regarding the cold is all the snow that remains on the ground up north. These were rported snow depths Monday morning.
This has really turned into a banner year for snow over the upper Midwest. Most of Minnesota and the north 2/3rds of Wisconsin have seen 60 to as much as 120 inches of snow!
The area near and NW of Minneapolis have been hardes hit relative to average with snowfall 200-300 percent above the mean.
The NWS in Minneapolis has 91.40" for the winter as of Monday. At least at that location, it is approaching the all-time record for the Twin Cities which is 98.6 inches. Some additional totals around the state.
Here's that seasonal totals in Wisconsin.
In Iowa we have quite the contrast. Way up in the NW corner 60 inches have been measured while in the southeast near Ft. Madison only 1.7 inches has come down. That's pretty wild!
PLEASE CONSIDER A DONATION TO SUPPORT THE CONTENT, INFRASTRUCTUE AND COSTS OF TSWAILS
As is often the case, when it's your year the storms find you and sure enough, the rich get richer with another storm (naturally on a Thursday) looking to find the same general area with the threat of more heavy snow.
For my area the system will be a rain maker until the tail end when some snow showers or flurries are possible, especially in the NW half of the region. What should please many of you is the warmer temperatures the system draws in ahead of it. We won't feel them as much Tuesday with highs remaining in the range of 35 north to 42 in the far south. However, with sunshine and a light wind regime, it's still going to be a fine late winter day.
Wednesday with the storm deepening to the west, brisk SW winds will send much warmer readings our way. Highs in most spots will hit the 50s (perhaps nearing 60 in SE Iowa) thanks to a strong mid-March sun. By Thursday clouds will be on the increase and precipitation gets underway by afternoon as the storm approaches. For sure the day starts mild but there is conflict regarding how long the warmth can hold Thursday. 40s NW to 50s SE are currently expected before readings hit the skids.
FLY IN THE OINTMENT
A caviat to watch is the amount of phasing that takes place between the northern and southern branches of the jet. Numerous time in the past 3 weeks I've discussed the challenges this process creates in modeling. A phased soultion brings a much stronger storm with heavier precipitation. Less phasing creates the opposite response and generally means a track further southeast. All models have shown a tendancy for less phasing and a weaker storm with lighter precipitation. As such, I expect primarily rain form the storm, maybe a brief changeover to light snow or flurries at the end of the event. Some minor accumulations are possilbe in my counites NW of the Quad Cities. The more significant precipitation should end by mid evening Thursday to be followed by some spotty snow showers or flurries Friday as sharply colder air and strong winds surge into the region.
Until the issue with track is resolved, it will be challenging to determine precipitation type, amounts, and placement. The system should have plenty of moisture to work with as the GFS shows water vapor (PWAT's) of an inch or more in most of the area Thursday afternoon...about 250 percent higher than normal.
Despite the moisture, the forcing dynamics make this a low confidence forecast in terms of precipitation amounts. Here's the range we currently have between the GFS and EURO. The south is favored for the more substaintial amounts. (If less phasing occurs these amounts could go down even more in the next 24-36 hours).
The GFS
The EURO
Snow totals show the importance of track. The GFS, EURO, and 3k NAM all have a different idea suggesting amounts that look like this.
The GFS
The EURO
The 3k NAM (I doubt it)
When it's all said and done, the next two weeks taking us to the end of March appear to be significantly cooler than normal. The week one average daily temperature departures look like this ending March 21st.
Week two ending March 28th is not much better. Yuk!
We get a real taste of it this weekend when highs St. Patricks Day and Saturday will not get out of the 20s, a time of year when normal highs are in the low to mid 50s. Plenty of wind Friday will make those St Patiricks day parades miserable with wind chills 5-15 degrees!
That's all for now. Chin up and roll weather, the next couple of days look pretty good...TS
