SALT LAKE CITY (ABC4) – It’s Monsoon Awareness Week and the North American Monsoon Season actually kicks off on June 15 and runs through September 30 but here in Utah, we usually see it ramp up after Independence Day.
We have a favorable setup heading into the weekend that mimics monsoon style and will help deliver winds, the threat of thunderstorms and increased deep-level moisture to a part of Utah. The atmospheric setup is a favorable flow pattern with an area of high pressure to our East and an area of low pressure in the Northwest, so it forces a southerly flow.
This allows for enhanced moisture from the South, in this case from the Gulf of California, to move into the Great Basin. This type of pattern screams monsoon style, but to understand what that fully means, we have to break down exactly how the monsoon season happens in the Beehive State.
The word “monsoon” actually means the seasonal reversal of winds. The seasonal change occurs in upper-level winds from the polar westerlies to tropical easterlies and includes a switch from dry west winds high up in the atmosphere to moist winds from the east or southeast. The rain actually starts to the south of us over southern Mexico when heavy rainfall starts in May and June. Rain quickly spreads north along the western slopes of the Sierra Madre Occidental mountain range and starts to move north. Typically, the monsoon season amps up in the Southwestern United States in early July and can hold on until mid to late September.
For Utah, we have a couple of key players when it comes to the monsoon which includes the “Four Corners High” and our sources of tropical moisture. We have two different sources of tropical moisture with the Gulf of Mexico and the Gulf of California. The Four Corners High sets up near southeastern Utah and has a clockwise flow, which helps draw moist, humid air into Utah. We get thunderstorm development when hot, unstable air rises and with plenty of mid and low-level moisture present during monsoon season. We can tap into heavy rain, numerous thunderstorms and frequently-triggered severe storms and flash flooding.
Utah has plenty of steep terrain and slick rock so flash flooding can tear through slot canyons and popular landscapes throughout the state. Monsoon thunderstorms can also be high-based or dry, meaning we get lightning but little rain to follow. This scenario is a big problem during fire season due to drought conditions, hot temperatures and at times, gusty winds, so lightning can easily spark a wildfire.
Last year, the summer of 2021 brought what some called the “miracle monsoon” with an abundance of moisture. While the water was welcome and helped drought conditions in the southwest corner of the state, the storms caused epic flooding in many Utah towns including Cedar City, Panguitch, Moab and at National Parks including Capitol Reef.
When it comes to water storage, you can’t really bet on monsoon moisture to help with drought conditions because the summer rains don’t reliably show up. We had several years prior to 2021 when the monsoon had little impact on Utah.
What will this year bring? Time will tell but be sure to stay with the Pinpoint Weather Team and Utah’s Most Accurate forecast for the latest forecast.
We are proactive when it comes to alerting the public to the threat of thunderstorms and flash flooding, so stay with us on-air and online. We are There4You!
