A meteorologist in California is warning of catastrophic weather events next week in California, including a deadly heatwave and monsoon-level rains.

Writing at Southern California Weather Force, “Meteorologist Martin” warns of “one of the strongest monsoonal and heatwave events this region has seen since July 2006.” Noting that the current temperature is 106 degrees in downtown Los Angeles, 115 degrees in the Inland Empire, and 111/112 degrees at Disney and Magic Mountain, Martin explains that after July 4, “we will see a major increase in temperatures as one of the largest heat-domes (ridge of high pressure) develops directly in the center of the country.” He says all this will be in addition to hurricanes expected in the south, which will “create inverted troughs through the Southwestern United States, kicking off monsoon season with a bang with showers and thunderstorms all the way through metro Southern California by the end this next week into next weekend.”

Martin said that anyone with plans to go to Disneyland, Magic Mountain, or Universal Studios should change them immediately. “This type of heat in the basins is deadly,” he explains. “In addition to the heat, we will have unbearable humidity.”

The reason for the extreme heat in southern California is “the east/southeast flow right off the mountains, similar to an offshore wind (Santa Ana Pattern).” However, he says, “this will be a humid and hot even as shower/thunderstorm activity develops and moves through the area, utilizing the energy in the atmosphere (hot air rises) from those temps.”

He predicts that Catalina Island will see 90-degree temperatures with high humidity, which will make it feel like Hawaii. “So if you fancy a Hawaiian vacation, hit that island this next weekend (after the 6th).” But, he warns, “take precautions hiking anywhere (not recommended).” He recommends taking extra precautions with pets and elderly.

The U.S. is currently experiencing a near-nationwide heat wave, with record temperatures reported in some areas. According to the National Weather Service, “Widespread, dangerous heat currently envelopes the central Plains to the western Ohio/Tennessee Valleys on Friday, with afternoon highs 10 to 20 degrees above normal and heat indices exceeding 100 degrees. Daytime highs and overnight high-minimum temperature records are possible across this region. This heat will expand eastward during the weekend and impact the Northeast and Mid-Atlantic.”

Do your best to stay cool and stay hydrated if you’re in one of the affected areas.