Friday, May 14, 2021 3:25 AM

Main Chance for Rain During Fishing Opener Weekend is Today

Only Second 70 of May Yesterday

High temperatures finally broke 70 degrees in St. Cloud for the first time since our near 90-degree high on the 1st of May (see 14-day graph of St. Cloud temperatures from MesoWest). So far, May has produced more highs in the 50's than in the 70's (see May St. Cloud high/low temperature table from National Weather Service). The warmer air has now covered much of the Northern Plains with pockets of 70-degree highs from Minnesota to Montana (see 4 PM Thursday NWS WPC North American zoom-in map). However, dew points (green numbers at lower left) continued to be only in the 20's and 30's, creating very low relative humidity and high to extreme fire danger (see Minnesota fire conditions from the Minnesota Dept. of Natural Resources).

Some Light Showers Moving into Minnesota Early This AM

The one thing that could mess up our warming trend is a storm that has moved from the Pacific Northwest into the Dakotas overnight (see Mid-tropospheric water vapor loop from Colorado State satellite slider). There have been some clouds and showers moving from the Dakotas towards Minnesota (see Shortwave Albedo from Colorado State satellite slider). The storms haven't been widespread since they are still fighting the low-level dry air. The strongest thunderstorms have been in Nebraska, but a few scattered showers have moved from the Dakotas into western Minnesota early this morning (see College of DuPage North Central US radar loop). With the dry air near the ground, not all of these showers are producing rain at the ground (see NWS Aviation Weather Center metar map), but there could be a few sprinkles or light rain showers this morning.

More Clouds With Some Showers Today, But Not Much Rain Likely

As the upper-air storm moves across southern Minnesota today, we will have a lot more clouds today and the chance for some scattered showers. During the afternoon, there may be a thunderstorm or two. One or two of these storms might drop some fairly large hail. These storms won't provide the amount of rain needed to alleviate the very dry conditions from the Dakotas into western and southern Minnesota, but it will be our best chance for rain over the next 5 days. The reduced amount of sun will keep our high temperature in the low to perhaps middle 60's. There will be strong southeast winds at 15-25 MPH.

Most Showers End Evening, and Fairly Mild by Sunrise

There could be a few more showers this evening, but partial clearing is likely after midnight. The additional moisture will help keep low temperatures in the 40's to near 50. If you're headed out to the lake first thing tomorrow morning, there could be some patchy fog, a bit of an east wind, and maybe some pockets of fog.

Some Sunshine, Slight Chance of Shower Saturday

On Saturday, there still will be a fair number of clouds and a small chance for an isolated afternoon shower (1 chance in 5). The return of partial sunshine will allow highs to climb into the middle to upper 60's. It won't be as breezy as today with winds from the southeast at 8-15 MPH.

70's To Return as Early as Sunday

Sunday is looking better with more sunshine likely than either today or tomorrow. That will allow high temperatures to return to the 70's. There still will be afternoon clouds and perhaps an isolated shower. Given the generally dry conditions and warm afternoon temperatures, fire danger will again be high to very high (see Minnesota fire conditions from the Minnesota Dept. of Natural Resources). You will have to monitor any campfires and be careful with any sparks as you head out to the wilderness this weekend.

We should be able to add to the warmer part of the May ledger as we head into next week. The main pattern is for high pressure across the Northern and Central Plains. Very warm temperatures are likely in Montana and the Dakotas with highs in the 80's or perhaps the 90's likely. In Minnesota, it looks more likely high temperatures well into the 70's Monday and Tuesday with perhaps an 80 or two in southern Minnesota. I can't completely rule out an isolated afternoon shower, but very few of us will see one.

Eventually, this pattern could lead to a threat of significant rainfall in Minnesota, but that probably won't happen until the middle or second half of next work week.

Detailed St. Cloud, MN, and Vicinity Forecast

Confidence Level: "While Preparing a Meal I Will Drop a Slice of Bread"

Friday 5/14/2021: Mostly cloudy, windy, and not as warm with a better chance of afternoon showers or thunderstorms. Elevated fire danger. High: between 60 and 65. Winds: SE 15-25 MPH. Chance of measurable rainfall: 50%.

Friday Night: Mostly cloudy with perhaps an evening shower, then some partial clearing possible late at night. Still mild. Low: between 45 and 50. Winds: SE 5-15 MPH. Chance of measurable rainfall: 30%.

Saturday 5/15/2021: Mixed clouds and sun and seasonably warm. A slight chance for a shower. Elevated fire danger. High: between 63 and 68. Winds: E 8-15 MPH. Chance of measurable rainfall: 20%.

Saturday Night: Partly to mostly cloudy and mild again. Low: between 42 and 47. Winds: E 5-10 MPH. Chance of measurable rainfall: 10%.

Sunday 5/16/2021: More sunshine, fewer clouds, and warmer. A slight chance of a late day shower. Elevated fire danger. High: between 70 and 75. Winds: SE 5-15 MPH. Chance of measurable rainfall: 20%.

Sunday Night: Partly clear and continued mild. Low: between 47 and 52. Winds: NE 5 MPH. Chance of measurable rainfall: 10%.

Monday 5/17/2021: Sunny in the morning, mixed sun and clouds in the afternoon with a slight chance of a shower. Continued warm. High: between 73 and 78. Winds: SE 8-15 MPH. Chance of measurable rainfall: 20%.

Confidence Level: "The Bread Will Land on the Floor Jelly Side Down"

Monday Night: Partly clear, breezy, and quite mild. Low: between 52 and 57. Winds: SE 5-10 MPH. Chance of measurable rainfall: 10%.

Tuesday 5/18/2021: Sunny to partly cloudy with a slight chance of an afternoon shower. Continued warm. High: between 73 and 78. Winds: SE 8-15 MPH. Chance of measurable rainfall: 20%.

Confidence Level: "My Sock Will Not Get Stuck to the Floor Because I Won't Step in the Jelly Spot"

Extended: Warmer with more consistent 70's early next week?? Better chance for showers by mid-week???

Forecast Confidence (10 - "The Rabbits Will Thump Even Though I Fed Them"; 0 - "The Rabbits Will Offer To Groom My Bald Spot"): 7 Friday through Saturday, 6 Saturday night through Monday, 5 Monday night and Tuesday.

Yesterday's High: 71°F; Overnight Low (through 3 AM Friday): 48°F
St. Cloud Airport 24-Hour Precipitation (through 3 AM Friday): None; SCSU Precipitation (through 3 AM Friday): None

Next Update: Monday, May 17, 2021 8 AM

Links

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.