There’s a tie-in with the mammoth hot air dome—the most expanded air mass to date this summer—and a tropical system arriving in California at tropical storm strength Sunday into Monday. The heat dome is forecast to develop over the nation’s mid-section late this weekend into next week

Here’s more on the potential flooding tropical rains which may occur there and how the mammoth hot air dome predicted to bring Chicago heat and humidity later this weekend into early next is impacting the tropical system’s movement:

Ocean temps are abnormally warm off Mexico’s west coast. Tropical systems feed on the moisture and latest heat energy these warm ocean waters provide. But it’s a powerful southerly steering flow aloft on the backside of the MAMMOTH HOT AIR DOME predicted to bring Chicago heat and humidity later this weekend into next week that are to guide Hurricane Hilary’s remnants—currently (as of Thursday morning) more than 1,000 mile south/southeast of the Golden State—which may guide the hurricane’s remnant torrential rains in the deserts of the Southwest and into California and Nevada.

Projected model atmospheric moisture levels are predicted to be 3 to 4 times normal as the system reaches the Southwest. This could unleash torrential rains capable of producing flooding on the region—a region which includes Phoenix, Tuscon, San Diego, Los Angeles and even potentially Las Vegas and Reno, NV.

Developing hot dome to build into the Plains and Midwest this weekend and into next week; vast area of steering winds around this hot dome is to latch onto “Hurricane Hilary” off Mexico pulling wind, waves and potentially heavy rains into California

  • “Hilary” could reach California as a rare “Tropical Storm” (sustained winds of 39+ mph) this weekend.
  • Potentially California’s first landfalling Tropical Storm since the “Long Beach Tropical Storm Of 1939″—84 Years Ago.
  • Flash Flood Watches are out as hot, humid air prepares to build into Chicago.

The mammoth dome of hot air predicted to build over the central U.S., including the Midwest, is to bring the Chicago area a run of hot, humid weather with inland 90s Sunday through Wednesday, shutting down rain in the process. Though the hot air mass is to produce 90s in the Chicago area, easterly winds off Lake Michigan may temper the heat a bit along Lake Michigan Sunday and Monday. The ENTIRE AREA is in for a run of high humidity which, combined with inland thermometer readings in the 90s, threatens triple-digit heat indices. ADVISORIES for heat may become necessary later this weekend into next week.


Fires burning in the record heat of recent days in the West are sending smoke eastward on upper steering winds. Skies over Chicago will reflect the movement of that smoke into our airspace. Computer model smoke projections indicate denser smoke will lend skies a “hazy/smoky” look Friday—smoke which will thin some on Saturday.