Fast spreading wildfires burning on sections of Maui and the Big Island in Hawaii

The fires rage as high winds—the product of a “tight” (i.e. “varied”) pressure gradient, strengthened by Hurricane “Dora” passing more than 700 miles south of the islands—and a sprawling 1032mb (30.47″) Pacific Ocean high pressure to the north. Reports indicating the town of Lahaina has been destroyed by fire.

Hurricane Dora and its CAT 4-level 130 mph peak sustained winds trekking 795 miles S/SW of Honolulu, Hawaii not impacting the Hawaiian Islands with its downpours

Big changes in pressure over a region produce strong winds and whip up high surf—particularly on the east-facing shores of the Islands. The non-hurricane wind gusts on Hawaii have topped 70 mph overnight, particularly at the Islands’ higher elevations—though winds are gusty elsewhere on the Island chain as well. So the fires being fanned by high winds AREN’T directly related to Dora—the hurricane’s effect in strengthening Hawaiian winds is indirect. Here’s how the situation is being summarized Wednesday morning by the National Weather Service Forecast Office in Honolulu:


“A strong high pressure system north of the state and Hurricane Dora are both moving westward this morning. Expect slow decreasing wind speed trends across the Hawaiian Islands today. Strong winds coupled with low humidity levels are producing dangerous fire weather conditions that will last through the afternoon hours. A more typical moderate to breezy trade wind weather pattern returns from Thursday into early next week.”


Nighttime Heat In Phoenix

NASA’s Jet Propulsion Laboratory (JPL) shows through weather satellite imagery the streets and other surfaces in Phoenix, Arizona growing progressively hotter in this past July’s heat—which continues there.

As NASA’s Jet Propulsion Laboratory researcher Glynn Hulley, the JPL climate scientist who produced the series, says:

“The images show how built surfaces – roads, buildings, airport runways, and the like – retain heat, sometimes hovering around 100 degrees Fahrenheit (38 degrees Celsius) for hours after sunset. From July 1 to July 19, the built surfaces in the maps grew progressively hotter, likely the combined effect of the heat wave intensifying and the cumulative heating of those human-made structures. Due to their high heat capacity, these surfaces didn’t fully cool overnight before the onset of the next day’s heat”