Hello everyone and happy Saturday! For today’s CONUS outlook, we will follow the usual format of breaking down the country into sections and looking at the big themes over the next week or so.
We will begin with taking a look at the 500MB map, which is good starting place for picking out the big features in-play currently in the CONUS.
Looking at the 500MB map, there are a few big features to pick out that are currently affecting weather across the CONUS. Most notably, are the two areas of high pressure and particularly the very broad one with a center near Oklahoma currently. As I’m sure many of you have noticed recently, much of the CONUS has been hot, with temperatures above average for much of the country. This can be attributed to the constant presence of a subtropical ridge over the country, along with zonal flow keeping cooler air trapped into Canada.
Western Part of CONUS
In terms of temperatures throughout the next week, ensembles are in general agreement that portions of the west, especially the Pacific Northwest will be above average.
While the Pacific NW takes the brunt of the above average temperatures, as you head east into Montana, Wyoming, and Colorado there is a better chance to see average or even below average temperatures.
Further investigating into the reason for this, we can see an upper-level low making its way across northern Canada, bringing more northwesterly flow to the regions expected to see below average temperatures.
You can see the more green and blue colors indicate a cooler air mass from Canada, which is allowed to be transported south thanks to the upper-level low bringing more northwesterly as opposed to the continuous westerly zonal flow.
Looking at the expected precipitation over the next 7-days, much of the western united states is expected to remain dry, except for Arizona, New Mexico, and Colorado, due to the continued moisture off of the Pacific and Gulf of California bringing rain to these regions and continuing the monsoon season.
Central / Southern CONUS
Moving onto the central and southern CONUS, severe weather is expected today in portions of Minnesota, Wisconsin, and Iowa. The areas are highlighted in an outlook by the SPC.
Taking a look at the 500MB heights and vorticity map, we can pick out a shortwave trough with enhanced areas of vorticity. This is an MCS, or a cluster of thunderstorms expected to cross through the region tomorrow.
The main risks from this MCS (mesoscale convective system) currently are damaging wind gusts of greater than 74mph (which is hurricane force!), as well as the possibility for a couple or tornadoes given the low-level shear, which allows for rotation to develop within these storms, leading to possible tornado development.
Otherwise, the rest of the week should feature temperatures continually above normal in the south and southeast, with temperatures below average to the north. This is due to the northwesterly flow bringing cooler air from Canada mentioned in the previous section.
Across the central and southern portions of the CONUS, heavier precipitation is focused in eastern portions of the Midwest and Great Lakes regions.
Northeast CONUS
In the northeast, temperatures continue to remain above average, with a slight cool down expected on Monday. Despite this cool down, temperatures are still expected to remain above average, just slightly cooler than this past week.
Precipitation is generally expected to be higher as you travel west, with decreased amounts closer to the coastlines. The next notable precipitation comes to the region on Monday, where a frontal boundary will cross through and lead to a spin up of thunderstorms.
Long Range Outlook
In terms of the long term (8-14 day) temperature outlook, it looks like everyone comes back to above average temperatures, besides portions of Arizona and New Mexico.
For precipitation, monsoonal moisture and conditions will provide above average rainfall for Arizona, with drier than normal conditions expected for the Pacific Northwest and Southeastern CONUS. The Great Lakes and portions of the Midwest may also experience above average precipitation in the long term.
