Classic spring now; severe risk next week?

Talk about a classic spring weather pattern.

A crisp morning gives way to a milder afternoon. A pristine blue sky drapes overhead. This is one of those rare days without a cloud in the sky across most of Minnesota. Note the still-white icy lakes.

GOES 1 km visible loop, via National Oceanic and Atmospheric Administration

We’ll see increased clouds Tuesday with a chance of light rain favoring the northern half of Minnesota.

Rivers running high

There’s still plenty of water in Minnesota’s rivers thanks to the rapid snow melt.

Close to average

The average high in the Twin Cities today is 63 degrees.

Temperatures this week continue to favor highs in the 60s in most of Minnesota, with a few 50s up north. Milder air this weekend pushes the numbers back into the 70s.

NOAA forecast temperatures for Minneapolis, via Weather Bell

Southwest flow

We’ve been living in northwest flow for the past several months. The upper-air maps finally suggest a southwest flow aloft. That brings warmth and probably heavy rain and thunder to Minnesota next week.

NOAA

Stormy next week?

Our weather pattern looks unsettled next week. Roving bands of thunder may bring the season’s first severe weather watches and warnings to parts of Minnesota.

The Canadian model captures the essence of roving thunderstorm waves with locally heavy downpours Monday through Wednesday of next week.

Canadian GEM model, via tropical tidbits

We could see our first severe watches and warnings next week.

NWS: 89 percent on April blizzard

The Twin Cities National Weather Service has given itself a grade of 89 percent on our recent April blizzard. I’d go even higher given the excellent lead time and overall forecast.

Twin Cities NWS

A slow moving, large low pressure system with copious amounts of cold air and moisture provided multiple rounds of precipitation from the early morning hours of April 13th through the early morning hours of April 16th.

The precipitation began as showers and thunderstorms across southern Minnesota which lasted into the evening of April 13th.  Precipitation then turned to snow from north to south during the evening.  Light snow persisted into the early morning hours of the 14th, before much heavier snow developed by mid morning and continued into early on the 15th.

The combination of visibility being so poor due to the intensity of the snow and wind gusts exceeded 35 mph prompted our office to issue the first Blizzard Warning for Minneapolis and St. Paul since the Halloween Blizzard in 1991.

The initial Winter Storm Watch was issued during the afternoon of April 11th.  Blizzard Warnings were issued in the afternoon of April 12th for portions of west central Minnesota, with Winter Storm Warnings issued further east during the evening of April 12th.  Blizzard Warnings were expanded eastward a few times, eventually reaching the Twin Cities area by early afternoon on April 14th.

Timing of the main round of snow was made complicated by ongoing precipitation and some minor uncertainty regarding the temperature profile of the atmosphere.  A couple points were lost due to those errors.  A couple points were also deducted due to under forecasting the magnitude of the snow.

For the Minnesota State Climatology Office write up of this event, please consult this link.

Local conditions and perceptions may vary from the objective grade calculated below.  Step through the other tabs to see a breakdown of the scoring.