St. Cloud, MN Weather Forecast

Warm Yesterday PM, But Still an Early Frost Yesterday AM

Yesterday, central Minnesota saw the reason to delay putting in sensitive plants until after the normal last frost date of the first week in May. Even though we were in a warm air mass that produced highs in the 60's and 70's (see yesterday's 4 PM CDT NWS WPC North America zoom-in map), the warmth came from air that was pulled down the eastern slopes of the Rockies (see southwest-to-northeast flow on the College of DuPage mid-level water vapor satellite loop). That flow has knocked the mid-summer-like humidity (dew points above 60 degrees) to a Kansas-eastern Iowa line (see yellow and orange on the UCAR hourly dew point chart). Meanwhile, the air pulled off the Rockies still had dew points in the middle 30's to middle 40's. Since we were clear and calm on Tuesday night, temperatures bottomed out colder than freezing in St. Cloud (see red line on the 7-day graph of St. Cloud temperatures and dew point from MesoWest). 

We have only gotten into the really humid air at the ground for a short time on Sunday (see blue line nose above 60 on that 7-day graph of St. Cloud temperatures and dew point from MesoWest). So, the persistent trend has been to be in the warm, but relatively dry air, so any clear, calm night has the potential of producing a frost.

Top of Temperature Roller-Coaster Today and Tonight

The dew points have edged up a bit since yesterday morning (now upper 30's to lower 40's, blue and green, on the 7-day graph of St. Cloud temperatures and dew point from MesoWest), but the moisture won't arrive in time to produce major precipitation when the storm off the Pacific Northwest (see southwest-to-northeast flow on the College of DuPage mid-level water vapor satellite loop) arrives by early Saturday. So, we will again go through the cycle of very warm temperatures today with highs well into the 70's, thanks to a milder start in the 40's (see NWS Aviation Weather Center METAR map) and a much stronger southeast wind. We will remain warm through tonight, with temperatures likely no cooler than the upper 50's by daybreak tomorrow.

Today's Actual Severe Weather Potential: Extreme Fire Danger

The winds will get very strong by midday today. That combined with the continued dry conditions (see updated US Drought Monitor, released later this morning) will produce a red flag warning, the highest category of fire danger, today from west central Minnesota into South Dakota. Fire danger will also be high in much of northern Minnesota (orange areas with special weather statement by NWS Duluth and Grand Forks). The Minnesota DNR statewide fire danger will be in the very high to extreme category after the morning update.

Severe Weather Awareness Week Has Tornado Drill This PM

Warm Season Severe Weather Awareness Week continues in Minnesota, Wisconsin, and South Dakota. The Minnesota statewide tornado drill will take place twice tomorrow afternoon and evening.

Temperatures to Crash Beginning Tomorrow Morning

The low coming from the Pacific Northwest will pull a strong cold front west-to-east through Minnesota tomorrow morning, bringing much cooler temperatures to Minnesota by the afternoon (temperatures likely to drop from the 50's and 60's early tomorrow to the 40's by midday and perhaps the 30's by 6 PM). The moisture isn't likely to get involved in this front until tomorrow afternoon, when the front will be past western and central Minnesota, so the precipitation potential (see Day 2 of the NWS WPC quantitative precipitation forecast) will be low with the best chance of central Minnesota showers around midday and the early afternoon.

Friday Severe Weather Potential Likely to Be From SE MN Eastward

The moisture will arrive to the east of the front by tomorrow afternoon, so there is again a good chance for severe weather in eastern Minnesota and especially eastern Iowa, western Wisconsin and Illinois (category 3 of 5 on the NWS Storm Prediction Center Day 2 convective outlook). A line of severe thunderstorms is likely, producing widespread wind damage, and there will be the chance for scattered storms early in the outbreak, which may produce several tornadoes and large hail.

Temperatures Bottom Out Saturday, But With Only a Few Flurries Possible

We will hit the bottom of the temperature roller coast on Saturday as temperatures drop from more than 20 degrees above average today to 20 degrees below average on Saturday. Temperatures Friday night will fall back into the upper or even middle 20's. Strong winds will develop in the colder air tomorrow afternoon and persist through Saturday, so wind chills will be in the teens. Saturday's highs will struggle to reach the upper 30's or lower 40's. The passing of the upper air low means a lot of clouds around and the chance for some flurries or snow showers with the best chance late Friday night or early Saturday. The forecast trend for the low arriving in Minnesota on Saturday has been further to the north, so the odds for any Minnesota snow accumulation are now limited to far north central and northeastern Minnesota (only green, 1 in 3 chance at best for an inch, when you set the time tab to 00 UTC Sun, 7 PM Sat, on the NWS WPC probabilistic winter precipitation guidance).

Frost Potential Sunday and Monday Mornings

We will have more opportunities for lows in the 20's both Sunday and Monday morning. Sunday's high will at least return to the upper 40's to near 50.

Temperatures Headed Up Again Much of Next Work Week

Another warm-up is likely much of next week. Highs are likely to be at least in the 50's and 60's, although it's too early to be sure of another day in the 70's or warmer. It will remain dry until a stronger, slow-moving storm expected to hit the West Coast early next week makes it into the Plains. The latest forecasts are more uncertain about whether there will be a pair of storm tracks, which could keep the humid air to our south, or one strong storm. In any case, I don't see significant precipitation until next weekend at the earliest.