Tuesday, March 19, 2024 4:15 AM
Prepared by Bob Weisman, SCSU Meteorologist and Professor Emeritus
The latter portion of March is shaping up to be more and more like the latter portion of an average February. The question remains how consistently cold we will be and how much snow there will be in various parts of Minnesota.
Yesterday Likely the Mildest Day of the Next 7
After another batch of late night and morning snow flurries, the clouds finally broke up over Minnesota yesterday (see Shortwave Albedo satellite loop from Colorado State satellite slider). That allowed high temperatures to climb into the upper 30's (see 4 PM Monday NWS WPC North America surface map). However, much warmer air was not far to the west, as high temperatures climbed into the 60's in the western half of the Dakotas into Wyoming and Montana. Even the air over Minnesota was ridiculously dry yesterday afternoon with dew points in the single digits (set time to 20Z-23Z, 3-6 PM, on the NWS Aviation Weather Center METAR map). There is now a small puddle of low 30's dew points in the eastern Dakotas (blue on the UCAR hourly dew point chart), but the cold front on the US-Canadian border (see latest NWS WPC North America zoom-in map) from this next storm will pass through with only a mixture of clouds and sun behind it. We might manage a few stray snowflakes this afternoon, but that will again do it.
40's Today With Fire Danger, Likely the Mildest Through Early Next Week
Our air flow aloft is northwest-to-southeast (see Mid-tropospheric water vapor loop from Colorado State satellite slider), so we won't get into the really toasty air. We will warm up a bit today, but we will have to settle for highs in the 40's. We will start off with a lot of sunshine (see Shortwave Albedo satellite loop from Colorado State satellite slider). There will be a lot of midday and afternoon clouds with a few stray snow flakes. Once again, the main concern will be very strong winds, that will again gust to 35-40 MPH from midday through the evening. Even though highs will be in the middle 40's, which is a little milder than the mid-March average, the dry air and strong winds will again produce very high to extreme fire danger.
Then, the northwest steering winds (see Mid-tropospheric water vapor loop from Colorado State satellite slider) will tap air from far northwestern and north central Canada for the rest of the week. Even though today's high in the middle 40's will not stand out compared to the warmer temperatures we saw earlier in March (see 30-day graph of St. Cloud temperatures from MesoWest), it is likely to be the warmest high temperature we will see until at least the middle of next week. Tonight will be breezy, holding temperatures in the upper teens to near 20, but producing wind chills near or perhaps below zero (see NWS Minnesota hourly weather round-up for the latest temperatures, wind speeds, and wind chills). Tomorrow, the northwest winds will blow at 10-20 MPH, but highs will be in the upper 20's to near 30, which is average in late February. Despite the cold temperatures, the fire danger will remain very high as the air will be very dry.
Moving Into Stormier Pattern With Thursday Night and Sunday Favored
The other change in our weather pattern from most of the second half of January through the first half of March is that we will be in a stormier weather pattern. The eastern Pacific has been very active most of the winter with several storms (see Pacific mid-tropospheric water vapor loop from Colorado State satellite slider). When strong storms have moved across the lower 48 over the past 2 months, they have remained in the southern US storm track, keeping the good moisture well to our south. And, really strong storms in the northern that could overcome some lack of moisture have mainly tracked either north of us or south of us, so that any narrow belt of heavy precipitation has missed. However, we have two potential storms to change that pattern this week.
Thursday Night System to Hit Southern Minnesota The Hardest?
The Thursday system is not actually a closed low, but a local speed-up of the jet stream (the dark area along and off the southeastern Alaska and northern British Columbia coasts; see Pacific mid-tropospheric water vapor loop from Colorado State satellite slider). That local jet stream maximum will race into southern Manitoba and extreme western Ontario by Thursday evening, providing lift along the boundary between the colder air we will have and the seasonably warm air to the south. This will produce a narrow band (100-150 miles) of plowable snow (4-8 inches) just to the north of its track, similar to the one from Valentine's Day. The trend in the computer forecasts has been to nudge the track of the warmer air riding over the cold air to the south. So, the best chance of that significant snow will be across southern Minnesota. The track of the system still could shift in the next day or so, but the recent runs would have the storm barely brushing the Twin Cities, if at all, and the bulk of the snow in the Minnesota River Valley and/or along the I-90 corridor in southern Minnesota (Luverne-Rochester-LaCrosse). The storm has also been delayed a bit, so the snow would only begin in west central and southwestern Minnesota Thursday afternoon and continue Thursday night.
For now, I am guess that St. Cloud will either have nearly all the snow passing to the south or catch the northern edge of the snow. So, I have included 3 inches in my range (low end: little to a dusting) in case the track does lurch back northward, but I am favoring a lighter snow for now.
Storm 2 Showing Sunday Snow Potential (Trending Towards Southern Minnesota, But It's Still Early)
The second storm would develop from the powerful low in the center of the eastern Pacific (see Pacific mid-tropospheric water vapor loop from Colorado State satellite slider). This storm is forecast to allow the northern and southern storm tracks to work together, which would bring a significant amount of moisture from the Gulf into the central and even the northern Plains. We haven't seen that consistently since our record breaking rainy December.
The computer forecasts continue to agree on the idea of a major Plains storm moving from Texas on Sunday to Iowa on Monday. On the northern and northwestern flank of the storm, the air will be cold enough to support snow, perhaps mixing with or tapering off to freezing drizzle at the end. The computer forecasts still move the track of the low with each computer simulation. However, there is a definite trend pushing the heavier snow accumulation to the south and east with each run over the past day. The US computer forecast gave the storm a weird northward jump on the last run, but all of the other information has been consistent.
I have found that a consistent trend is often more important that the actual details. While the computer output shows the highest precipitation potential in both central and southern Minnesota, I'd cautiously bet that southern and southeastern Minnesota and northern Iowa are the most likely to see major travel issues with this storm, which will produce more precipitation than Thursday night's system (see Days 6-7 on the NWS WPC quantitative precipitation forecast). The maximum accumulation could easily be in the 6-12 inch range (see Days 5 and 6 on the NWS WPC winter weather outlook), and will come with a lot of wind, so I would start considering Plan B if you have travel plans to South Dakota, southern Minnesota, the Mississippi Valley from the Twin Cities southward, and northern Iowa Saturday night through Sunday night. For now, it appears the heaviest precipitation will fall during Sunday morning and midday. This system will be larger than the Thursday system, so I am not ready to rule out shovelable snow (although a lighter amount) for St. Cloud. Also, with the main storm over the ocean, there could be changes in later computer forecasts that shift the snow back to the north. It's still early and I'd like to especially see the next US computer run to see if the northward lurch was an outlier, but that's my educated guess.
Depending on which computer run you like, some of the precipitation could be mixed or even rain in the southern part of the heavy precipitation, but I am liking the bulk of the precipitation in Minnesota as snow, then tapering to freezing drizzle as it ends.
I Don't Want to Talk About Storm 2b or 3 for Monday or Tuesday
There is also the chance of a second wave of this storm system with more precipitation sometime Monday or Monday night. A forecast of that is way out of my comfort zone for now.
If most of central and southern Minnesota picks up snow between the Thursday night and weekend storms, then any temperature rebound early next week will be held back. So, I have February-like temperatures continuing into early next week.
Detailed St. Cloud, MN, and Vicinity Forecast
Confidence Level: "The Bugs Are Waiting for Me to Mow the Lawn"
Tuesday 3/19/2024: A sunny start, then mixed clouds and sun with a few stray snow flakes, blustery with seasonable temperatures. Very high fire danger. High: between 42 and 47. Winds: NW 15-30 MPH with gusts over 40 MPH. Chance of measurable snowfall: 10%.
Tuesday Night: Clearing, windy, and much cooler. Low: between 15 and 20. Winds: NW 15-30 MPH with gusts over 35 MPH evening, 10-20 MPH with gusts over 25 MPH late at night. Wind chill between -5 and +10. Chance of measurable snowfall: 10%.
Wednesday 3/20/2024: Lots of sun through some afternoon high clouds, not quite as windy, but colder. High: between 25 and 30. Winds: NW 10-20 MPH. Wind chill between 0 and 10 in the morning, between 10 and 22 in the afternoon. Chance of measurable snowfall: 10%.
Wednesday Night: Thickening clouds, lighter winds, and not quite as cold. Low: between 20 and 25. Winds: NE 5 MPH evening, SE 5 MPH late at night. Wind chill in the teens. Chance of measurable snowfall: 20%.
Confidence Level: "Extra Bugs Will Come From Every Home on the Block to Hover Around My Head"
Thursday 3/21/2024: Cloudy with occasional flurries. Some steadier light snow may be possible in the late afternoon. Still cold, but not nearly as windy. High: between 27 and 32. Winds: SE 5-15 MPH. Wind chill in the teens. Chance of measurable snowfall: 20%.
Thursday Night: Cloudy with a chance of steady snow or flurries through the evening, tapering to flurries late. Between a dusting and 3 inches of new snow is possible by morning. Low: between 25 and 30. Winds: SE 5-15 MPH evening, shifting to NE 5-15 MPH in the early morning hours. Wind chill between 0 and 15. Chance of measurable snowfall: 50%.
Friday 3/22/2024: Cloudy, breezy, and colder. A chance of flurries or a few snow showers. High: between 30 and 35. Winds: NW 10-20 MPH. Wind chills: between 5 and 15 in the morning, between 10 and 22 in the afternoon. Chance of measurable snowfall: 20%.
Friday Night: Clearing with slowly diminishing wind and colder. Low: between 5 and 10. Winds: NW 8-18 MPH evening, NW 5 MPH after midnight. Wind chill: between 0 and 15 evening, between -5 and 0 late. Chance of measurable snowfall: 10%.
Saturday 3/23/2024: Sunshine through increasing high clouds, lighter winds, but colder. High: between 22 and 27. Winds: SE 5-10 MPH. Wind chills: between 5 and 15 in the morning. Chance of measurable snowfall: 10%.
Confidence Level: "Enough Bugs Will Fly into My Mouth to Throw Off My Diet"
Extended: Continued colder than average through early next week??? A major snowstorm possible Sunday and Sunday night???? Favoring Southern Minnesota for the most snow????????
Forecast Confidence (10 - "The Rabbits Will Thump Even Though I Fed Them"; 0 - "The Rabbits Will Offer To Groom My Bald Spot"): 8 Tuesday through Wednesday, 6 Wednesday night, 5 Thursday and Thursday night, 4 Friday through Saturday, 2 Sunday.
Yesterday's High: 38°F; Overnight Low (through 4 AM Tuesday): 31°F
St. Cloud Airport 24-Hour Melted Precipitation (through 4 AM Tuesday): Trace; SCSU 24-Hour Precipitation (through 3 AM Tuesday): Trace
March 19 Historical Data | High | Low |
Average Temperatures | 42°F | 23°F |
Record Temperatures | 78°F (2012) | 59°F (2012) |
15°F (1965) | -12°F (1965) |
Next Update: Wednesday, March 20, 2024 6 AM
Let me know what you think about this forecast and discussion by emailing SCSU meteorology professor Bob Weisman. Please note that I make the forecast, not the weather!
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