A State Divided

In our previous post, we discussed some uncertainties in the forecasts for early next week, with differences in the amplitude and timing of a late-June upper-level trough that was expected to affect Utah's weather. 

The model spread has decreased some in the past couple of days with both the GFS and the ECMWF now going for a solution that favors a frontal passage over northern Utah on Sunday (probably noon or later, but follow forecasts as this could change) with the front moving very slowly across the state through Tuesday.

On Monday, we will be a state divided meteorologically.  At 0000 UTC 30 June (1800 MDT Monday), the GFS forecast puts the surface cold front over central Utah, with unseasonably cold, northwesterly flow over the northern and western portions of the state and warmer southwesterly flow over southwest Utah. 

The ECMWF has a very similar solution, as illustrated by the surface temperature forecast below, with a 30˚F temperature contrast between southeast Utah and Cache Valley. 

Source: Pivotal Weather

Direct model temperature forecasts can exhibit large biases, so I don't use the absolute values of those numbers above for anticipating actual temperatures, but the National Weather Service is currently forecasting a high of 67˚F for the Salt Lake City airport on Monday, which would be 22˚F below average. 

Monitor forecasts for evolving details, but be prepared for big changes.