St. Cloud, MN Weather Forecast

First 90-Degree High of Season Yesterday, But Drier Air Moved In

Sorry about no forecast yesterday. I had a 15 hour Internet outage.

St. Cloud finally got to 90 degrees yesterday (afternoon high of 91; see NWS: last 72 hours of St. Cloud observations) for the first time since October 4. However, the heat index, a reading that reflects both the heat and the humidity, never got past 88 degrees in St. Cloud and never got higher than the temperature in places that reached 90 or above yesterday afternoon (set NWS Minnesota hourly weather round-up to 2-5 PM). That was caused by a wind shift to the northeast (set time to 18Z-23Z, 1-6 PM CDT, on the NWS Aviation Weather Center METAR map), bringing in drier air from Lake Superior and Ontario. The drying trend has continued overnight as dew points have fallen back to the 40's in central Minnesota with even some 30's near the Canadian border (see green and blue on the UCAR hourly dew point map).

US-Canadian Plains High Will Keep the Heat and Dryness Around

Weather systems have generally come to a halt or are moving in strange directions right now, thanks to a large high pressure circulation over Nebraska and South Dakota (clouds moving towards the north or northwest over the Rockies, but moving southward over Minnesota on the College of DuPage clean infrared satellite loop). It may appear that the low pressure system (counterclockwise circulation moving from the Texas Panhandle to Colorado and causing huge blobs of thunderstorms to its east; see College of DuPage North America mid-level water vapor satellite loop) will have a good chance of spreading showers and thunderstorms over Minnesota.

However, the high is the system that will intensify and move into the Dakotas and south central Canada. So, the low pressure system will be steered northwestward, producing a lot of rain in Montana and the Dakotas (see NWS WPC quantitative precipitation forecast), but there will only be some isolated showers and thunderstorms mainly brushing southwestern Minnesota through the weekend into early next week.

Instead, the stalled high will continue to circulate air from Ontario and Manitoba into most of northern and central Minnesota. So, most of the next few days won't be quite as humid as yesterday morning, although we will still see periods with the dew points in the upper 50's to perhaps 60 with the best chance tomorrow into tomorrow night.

Prolonged Warm Period Will Continue Into Next Week

High temperatures will generally remain in the 80's into early next week, continuing our most prolonged summer-like temperature streak of the warm season so far. We might have a shot at a 90-degree high again on Saturday. But, low temperatures will be able to fall back into the 50's, thanks to the drier air around.

Heat and Lack of Rain Will Aggravate Dry Conditions

We will only see a slight chance of a late day shower or thunderstorm at times over the next couple of days with the best chance (1 in 3) tomorrow. 

This heat will intensify the effect of the rainfall shortage. We lose moisture when we get little rain. Most of Minnesota, except the south central and northeast parts of the state, has been short on rain in May (set date to yesterday and time period to last 30 days on the NWS Water Prediction Service Minnesota map). That continues the issue of dryness caused by the rain shortfall that began last August (set time period to last 180 days on the same NWS Water Prediction Service Minnesota map). In St. Cloud, we were 4.44 inches behind from last August through November (10th driest Aug-Nov on record). Since March 1, St. Cloud has fallen another 1.48 inches behind (5.85 inches actual precipitation, 7.33 inches average precipitation). We share this problem with much of the Southern Plains states (see US Drought Monitor) and parts of the Southeast, although they will be getting some major rainfall the next 7 days.

We lose moisture faster through evaporation when it is hotter. So, less water 'income' and more water 'spending' means faster drying out.

So, the elevated to extreme fire danger conditions will continue, especially in northern Minnesota, into the weekend.