Plaincast

Messages

Hot and mostly dry conditions continue this week.

Smoke continues across the region this week, reductions to visibility and air quality are possible.

Isolated strong thunderstorms in Southeast Montana this afternoon and evening capable of producing wind gusts of 65 mph over far southeast MT.

Daily chance (10-30%) for afternoon and evening showers and thunderstorms through the week.

Discussion

There are already a lot of mid level clouds building in across the forecast area associated with lingering convection. This combined with the wildfire smoke will play a role in limiting our temperatures today. The extent to which the temperatures will be suppressed is still a question due to the fact that the smoke and clouds are not uniform and breaks in either or both could result in quick heating.

A shortwave trough is forecast to push through the area similar to what happened yesterday. Showers and thunderstorms are forecast to form over the mountains and move off the terrain this afternoon. Stronger storms are possible in extreme southeast MT where the temperatures may be hotter with a slight increase in mid-level moisture. Inverted-V forecast soundings suggest a primarily wind threat and with saturated mid levels, wet microbursts are possible in the SPC marginal risk area this afternoon. The surface temperature question posed above will play a role in convection later today for the marginal area. If we are unable to heat up enoug then there will probably be much less coverage in storms that will require the main CVA ahead of the trough to initiate. Bulk wind sheer is slightly better today with much of the forecast area forecast to be between 20-30 knots which, in theory, should support storm maintenance more than we saw yesterday. Long straight hodographs with good cloud level moisture will support the upscale growth of storm clusters as they progress eastwards.

There continues to be no progressive flow aloft through the entire work week and thus the ridge shows little to no signs of changing for several days. Highs in the 90s to 100s appear likely to stick around into for the remainder of July. This could pull some monsoonal moisture up into the region with the chance for some showers and storms each day, particularly near the mountains, however coverage will be scattered any given day therefore resulting in a low chance for wetting rain. That being said, climatologically high PWATS will allow for downpours under the stronger storms resulting in an very quick wetting rain for those localized areas. Additionally, wildfire smoke from the several complexes in Eastern OR will also continue to be around the area due to the predominately westerly flow. This smoke, or lack of smoke, will play a large role in our temperatures over the next several days.

Models are now showing an increase in moisture over the eastern 1/4 of the forecast area into the middle of the week which could turn into a heavy rain and marginal severe weather risk every day through Friday. This will need to be monitored as wildfire smoke, the strength of the monsoonal flow, the position and strength of the vort maxes, and just how much surface moisture is advected out of the plains are all variables that we still have questions around.

There continues to be a signal that a ridge crasher event may impact our area next weekend which would usher in cooler temperatures behind it. This type of event would also bring the potential for gusty winds and maybe some storms as well which would be a potential concern for fire weather after a prolonged stretch of hot and quasi-dry conditions. WMR