Wednesday, January 18, 2017 3:21 AM
Prepared by Bob Weisman
Professor of Earth and Atmospheric Sciences
Saint Cloud State University
Earth and Atmospheric Sciences Department
Saint Cloud and Vicinity Forecast
January Thaw Through Much of This Week
There was a painfully slow drying yesterday, especially during the afternoon, as slightly colder air drifted in from western Minnesota. This allowed us to see some sunny breaks yesterday afternoon, although low clouds did dominate the day (see infrared satellite loop from College
of DuPage Satellite and Radar Menu). The slightly drier air also was less polluted. The Air Quality Index actually reached the unhealthy for sensitive groups level in parts of north central Minnesota into the Duluth area, but those eased off a bit in the afternoon.
Overnight, there have been mostly clear skies across Minnesota, but low clouds remain persistent across eastern Minnesota (see Colorado
State RAMDIS Western US Fog/Reflectivity Product). In central Minnesota, the clear skies and light winds allowed temperatures to fall back into the teens by late evening (see UCAR
Minnesota surface chart), but clouds to the east and the developing southeast winds to the west have pushed temperatures back into the 20's to near 30 degrees in some areas. These temperatures are 15-20 degrees warmer than average (see hourly temperature departure from normal from Penn State ewall).
This will be our pattern for much of the week. Temperatures will climb above freezing mostly likely each day, but the more unusual readings will be very mild low temperatures. Readings in the 20's will be common with lower to even middle 30's likely later in the week. That could threaten some record warm low temperatures beginning Friday morning.
Today, we will have a better chance of seeing periods of sunshine. However, with the generally light winds and the moisture added to the lower atmosphere by melting snow, we will see periods of low clouds along with the sun. Highs will climb into the middle 30's. Tonight, the additional moisture in the air will keep low temperatures in the 20's. There will be some spotty fog, but the persistent southeast winds should keep the fog from being too dense. Tomorrow, we will have more cloudy periods and less sunshine. Temperatures will again climb into the middle 30's.
By Thursday night, there will be enough moisture in the air from snow melt to develop dense low clouds. There may be enough wind to keep the visibility in any fog from getting too low, but there could be some isolated spots of low visibility. Unfortunately, given the moistening of the air locally and the passing of a storm off to our southeast, the light southeast winds will only bring in air that is saturated, so we may not be able to break the low clouds and fog much from Friday through the weekend. There will be periods of drizzle and it is possible that overnight temperatures dip below freezing, making the drizzle a freezing drizzle. There is a chance of some steadier precipitation on Saturday as a dying low pushes into Minnesota from the southeast, but I don't expect much of the way of precipitation. It should be mild enough at the ground that any precipitation melts on contact.
So, the main issue will be the lack of sunshine, the very moist conditions, and the possibility of seeing more relatively high levels of air pollution. Overnight, the Air Quality Index (see Minnesota Pollution Control Agency hourly air quality map) has retreated to the lower half of the moderate category in central and southern Minnesota. However, the combination of the warm air trapping leftover cold air near the ground, the light winds, and the pollution generated by normal traffic in the Twin Cities will gradually lead to higher pollution levels as the week goes on. I wouldn't be surprised to see the air quality index approach or break 100 by late in the week. The only good news is that the more stagnant air is forecast to be here over the weekend, when there is generally less new pollution generated by traffic.
Still, the increasing low level moisture will cause problems for those with a history of sinus ailments. And, by late in the week, we may have to watch the air pollution problems.
Confidence Level: "The Rabbits Will Sniff At My Feet While I'm Forecasting"
Wednesday 1/18/2017: Mixed sun and clouds, light winds, and continued mild. High: between 32 and 36. Winds: S 5-10 MPH. Chance of measurable snowfall: 10%.
Wednesday Night: Partly clear with areas of fog possible late. Low: between 20 and 25. Winds: SE 5 MPH. Chance of measurable snowfall: 10%.
Thursday 1/19/2017: Cloudy with some morning fog possible. Milder. A slight chance of some drizzle. High: between 32 and 36. Winds: S 5 MPH. Chance of measurable precipitation: 20%.
Confidence Level: "The Rabbits Will Want Petting with One Hand, While I'm Typing the Forecast"
Thursday Night: Areas of fog, breezy, and milder. Maybe some drizzle. Low: between 30 and 35. (record warm low: 32 set in 1900) Winds: SE 5-10 MPH. Chance of measurable precipitation: 20%.
Friday 1/20/2017: Cloudy with perhaps some morning fog. Maybe some spotty drizzle. High: between 34 and 38. Winds: SE 5-10 MPH. Chance of measurable precipitation: 20%.
Friday Night: Low clouds and fog with some spotty drizzle possible. Low: between 32 and 34. (record warm low: 34 set in 1934) Winds: E 5-10 MPH. Chance of measurable precipitation: 20%.
Saturday 1/21/2017: Continued murky and mild with some spotty drizzle or occasional light rain. High: between 34 and 38. Winds: SE 5-15 MPH. Chance of measurable precipitation: 30%.
Saturday Night: Low clouds and fog with some spotty drizzle possible. Low: between 32 and 34. (record warm low: 34 set in 1934) Winds: E 5-10 MPH. Chance of measurable precipitation: 20%.
Sunday 1/22/2017: Low clouds and fog in the morning. Perhaps a little brightening in the afternoon. High: between 34 and 38. Winds: light. Chance of measurable precipitation: 20%.
Confidence Level: "The Rabbits Forecast That Most Precipitation Will Be in the Form of Lettuce"
Extended: Cloudy and continued mild Sunday.
Forecast Confidence (10 - "Know what gas will
cost next week, Bob?"; 0 - "Been a victim of road rage lately, Bob?"): 7 Thursday through Saturday, 6 Saturday night and Sunday, 4 Sunday night and Monday.
Yesterday's High: 30°F; Overnight Low (through 3 AM): 17°F
St. Cloud Airport Precipitation (through 3 AM Wednesday): None; SCSU Precipitation (through 3 AM Wednesday): None
Normal Temperatures for January 18 - High: 21°F;
Next Update: Thursday, January 19, 2017 8:00 AM (or as needed)
Ground and Air Travel
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!
Are you interested in studying meteorology? If so,
go to the Atmospheric and Hydrologic Sciences Department home page.