Local Forecast

Friday, January 20, 2017 3:18 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


Murky Side of Mild Through the Rest of the Week


While there continue to be strong low pressure systems wandering from the Southwest into the Plains states (see the number of counterclockwise circulations on the water vapor loop from College of DuPage Satellite and Radar Menu), with the latest one pulling rain and some spotty freezing rain (see infrared loop) through Wisconsin in the early morning hours (see NWS Upper Mississippi Valley radar loop), the main weather that will dominate conditions from now into early next week is the large bank of low clouds and fog that extends from central Minnesota and the Dakotas to Missouri and eastern Oklahoma (see Colorado State RAMDIS Western US Fog/Reflectivity Product). In the area affected by the rain showers from the deeper storm, visibility has remained mostly above a mile in the fog (see UCAR Minnesota surface chart). However, from southern Minnesota into Iowa especially, visibility is down to a quarter mile or less in many areas. In fact, the National Weather Service has a dense fog advisory out from the central Dakotas through west central and southern Minnesota all the way to Kansas and Missouri. In Minnesota, the advisory includes Morris, Willmar, Alexandria, Granite Falls, Redwood Falls, Marshall, Mankato, Faribault, Owatonna, Red Wing and the entire I-90 corridor.

So, today will likely be the first of the promised murky and moist days. Much of southern and central Minnesota has temperatures that have bottomed out above freezing, so the threat of freezing drizzle (see UCAR Minnesota surface chart) only exists in a few pockets of lake country and northern Minnesota. Still, it will be quite miserable with temperatures in the middle to upper 30's and clouds dominating the day.

The fog will tend to thicken this evening as the ground cools a bit. However, the next counterclockwise circulation, now over northern Arizona and New Mexico (see water vapor loop from College of DuPage Satellite and Radar Menu), will push all the way into Minnesota by tomorrow afternoon. This will produce another round of steady rain, but more of this rain should track over Minnesota from late tonight through tomorrow. It won't be a heavy rain, but during the rainfall, visibility should climb enough to make travel easier. There is a chance that the precipitation could fall as a mixture in northern and northeastern Minnesota, but the large number of above freezing temperatures early this morning gives me hope that temperatures will stay above freezing in most of Minnesota tonight.

That rain will taper off Saturday night, so thick fog with very low visibility will be a widespread threat again.

While temperatures will be well above average for this, the coldest part of the winter, daytime temperatures won't exactly be a heat wave. Highs will mostly be in the middle to upper 30's with a few 40's possible tomorrow as the next low brings slightly milder air in. We will gain on average temperatures the most overnight, since all of this low level moisture has the potential to keep low temperatures at or even above freezing, more than 25 degrees above average. This morning's low is likely to stay above freezing, which would break the January 20 record warm low of 32 degrees, set in 1900. We will have a shot at breaking tomorrow's record mild low (34) with a better chance of beating the record warm low of Sunday (32) and Monday (33).

Murky Air Will Cause Health Problems, Maybe Air Quality Problems

Unfortunately, this mild weather could still produce air quality problems. The overnight light rain helped us stay in the moderate category (see Minnesota Pollution Control Agency hourly air quality map), but we do have a regular weekday commute today, so pollution levels might approach the unhealthy indices. Less traffic over the weekend, a slightly larger depth of atmosphere to mix the pollutants, and the better chance of rain tomorrow hopefully will keep the air quality out of the upper moderate or unhealthy for sensitive groups category. However, there will be no relief from the moist cold all the way into early next week. Those with sinus conditions and other ailments sensitive to these conditions will unfortunately have a tough weekend.

Storm Next Week?

There is a possibility for a stronger storm to affect Minnesota on Tuesday into Wednesday. There is considerable disagreement about the storm track, but that storm would have the potential to produce considerable precipitation. Any relief from the persistent low clouds will have to wait until after that storm for a fresh source of dry air to push into Minnesota.

In the meantime, the third storm, now pushing into southern California and bringing important rain and snow to the Southwest, has the potential to produce heavy rain and severe thunderstorms over the Gulf Coast and Southeast this weekend.

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Confidence Level: "The Rabbits Will Sniff At My Feet While I'm Forecasting"

Friday 1/20/2017: Mostly cloudy with areas of fog and some spotty drizzle. High: between 35 and 40. Winds: E-SE 5-10 MPH. Chance of measurable rainfall: 20%.

Friday Night: Low clouds and dense fog evening. Maybe a few rain showers with improved visibility late. Low: between 33 and 36. (record warm low: 34 set in 1934) Winds: E 5-10 MPH. Chance of measurable precipitation: 50%.

Saturday 1/21/2017: Continued murky and mild with a better chance of some steady rain. High: between 38 and 44. Winds: E 5-10 MPH. Chance of measurable rainfall: 60%.

Confidence Level: "The Rabbits Will Want Petting with One Hand, While I'm Typing the Forecast"

Saturday Night: Mostly cloudy with areas of dense fog and spotty drizzle. Low: between 32 and 34. (record warm low: 32 set in 1900) Winds: NE-NW 5-10 MPH. Chance of measurable precipitation: 20%.

Sunday 1/22/2017: Mostly cloudy with some dense fog possible in the morning, breezy, and not quite as mild. A chance of occasional rain or wet snow showers. High: between 35 and 40. Winds: NW 5-10 MPH. Chance of measurable precipitation: 50%.

Confidence Level: "The Rabbits Forecast That Most Precipitation Will Be in the Form of Lettuce"

Sunday Night: Mostly cloudy with a chance of some fog and freezing drizzle or drizzle. Low: between 30 and 34. (record warm low: 33 set in 1909) Winds: NW 5 MPH. Chance of measurable precipitation: 20%.

Monday 1/23/2017: Mostly cloudy with morning fog and drizzle. Maybe some afternoon sunny breaks. High: between 35 and 40. Winds: W 5-10 MPH. Chance of measurable precipitation: 20%.

Monday Night: Mostly cloudy with a chance of evening fog. Maybe some snow late at night. Low: between 30 and 34. (record warm low: 32 set in 1944) Winds: SE 5-10 MPH. Chance of measurable precipitation: 30%.

Tuesday 1/24/2017: Cloudy with a chance of snow. High: between 32 and 35. Winds: W 5-10 MPH. Chance of measurable precipitation: 40%.

Extended: Next storm with potential for more signficant precipitation middle of next week.

Forecast Confidence (10 - "Know what gas will cost next week, Bob?"; 0 - "Been a victim of road rage lately, Bob?"): 7 Thursday and Thursday night, 6 Friday through Saturday, 5 Saturday night and Sunday, 3 Sunday night and Monday.

Yesterday's High: 40F; Overnight Low (through 3 AM): 34F
St. Cloud Airport Precipitation (through 3 AM Friday): None; SCSU Precipitation (through 3 AM Friday): None

Normal Temperatures for January 20 - High: 21F; Low: 1F
Next Update: Monday, January 23, 2017 8:00 AM (or as needed)

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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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