Omega block: Weather geek for a San Diego-like forecast

Welcome to San Diego. With lakes. And corn dogs.

The atmosphere over Minnesota is blissfully stuck this week. A building dome of high pressure stalls overhead. The result? A string of mainly sunny and increasingly warm and dry days across the Upper Midwest. In weather speak, we call this pattern an Omega Block. The upper winds look like the Greek letter Omega on the maps.

Omega blocks bring warm dry weather underneath, with cold and wet on each side. In this case that means perfect spring weather in the Midwest, cool and wet on the coasts.

At ground-level where we live, a stalled high pressure ridge over the Great Lakes.

Let's cut to the forecast chase. A week of generally sunny days and moonlit nights with highs in the 60s and 70s. Pure weather bliss.

Drying out

Farmers in southern Minnesota need the sunny warm weather this week. Here's an update on conditions from this week's Minnesota Crop Report.

Below normal temperatures throughout Minnesota slowed crop development and raised concerns about freeze damage in the northern and central parts of the state during the week ending May 15, 2016, according to USDA’s National Agricultural Statistics Service.

There were 2.3 days suitable for fieldwork, with the southern parts of the state limited to 1.5 days or less due to continued precipitation. While planting is nearing completion for several crops, farmers are looking for warmer temperatures to support development.

This string of dry days will suck about two-tenths of one inch per day from the ground. Here's the daily evapotranspiration rate map from the University of Wisconsin.

Smoke aloft

There's still a bit of smoke aloft this week, as fires continue to burn in eastern Alberta and western Saskatchewan. Northwest flow aloft is carrying a somewhat diffuse plume toward Minnesota and the Dakotas.

So far air quality is good, but that may change later this week.

Stay tuned.