Western Heat Predicted to Move East

The extreme heat that is helping to fan severe western wildfires from California to Alaska is predicted to move eastward over the coming days. This shift is expected to set off high temperatures in the 90s and 100s from the Gulf Coast all the way to the Great Lakes and into the Northeast. Heat Index values, meanwhile, are predicted to spike into the 100s and 110s from the Mississippi Valley north and eastward.

(Much warmer than normal temperatures spread from west to east across the U.S.)

These much warmer than normal temperatures and potentially dangerous heat index values occur in a context of larger national and global warming. May of 2018 was the hottest on record according to NOAA. The U.S. presently sits between two warmer to much warmer than normal ocean zones. And overall global temperatures have been rising since the 1900s, with a more rapid up-ramp occurring since the late 1990s.

For the Central and Eastern U.S., warmer than normal oceans are also spiking atmospheric moisture levels through increased rates of evaporation. These higher moisture levels will be contributing to predicted heat indexes where large regions are expected to experience temperatures that feel like the 100s or 110s (see image below).

(Heat index values are predicted to rise to between 40 and 45 C for large parts of the Central and Eastern U.S. The 44 C predicted heat index for parts of Western New York on July 1 corresponds to a 111 F ‘feels like’ condition for this Northeastern region. Such high heat index values present a heightened risk of heat injury due to long term exposure. Image source: Earth Nullschool.)

Combined high heat and humidity increase the risk of heat injury due to exposure. And rising heat indexes and wet bulb temperatures are just one of the many potentially harmful aspects of human caused climate change.

From Inverse:

In the future, parts of the world will become so hot and humid that healthy adults sitting in the shade will die within a matter of hours. It’s hard to imagine, and yet that’s where Earth’s climate is headed, perhaps sooner than expected.

But while many recent studies have rightly focused on physical human limits under high wet bulb temperature risks for parts of South Asia and the Middle East, the Central to Eastern U.S. is also a region of concern. Climate risks to this region of the U.S. are due to both high predicted temperatures and high moisture levels from increasingly warm Gulf and Atlantic Ocean surfaces. The result is that heat capable of resulting in rapid heat injury or even loss of life, with wet bulb temperatures above 35 C, is possible by mid-to-late Century under high fossil fuel burning scenarios.

(At 10 C global warming, large regions of the world are regularly predicted to experience temperatures above 35 C Wet Bulb readings — or a level at which the human body is not naturally capable of cooling itself. Of course, such dangerous Wet Bulb readings are possible under still lower levels of global warming. Note that the Central to Eastern U.S. is one of the indicated hot spots from this recent paper.)

Though the Eastern U.S. is not yet facing extreme wet bulb readings of this kind, temperatures and humidity levels are presently on the rise. So the predicted heat wave is still expected to pack a punch. And perhaps a bit more than we’re used to.

We’re looking at a predicted extended period of significant above normal temperatures and high humidity over the coming days. So the public should stay tuned to local media for heat advisories issued by the National Weather Service (see heat safety tips here) and do what they can to keep cool by drinking water frequently and by spending less time exposed to blazing temperatures and sweltering humidity.

Advertisements

U.S. Climate of Troubles: Record Heat Out West, Severe Floods in the East

Yesterday a record heatwave affecting 40 million people cracked pavement, grounded flights, threatened power grids and risked serious injuries across the Southwestern U.S. Meanwhile, today, a heavily moisture laden tropical storm Cindy is threatening to dump 10 to 15 inches or more of rain on parts of the U.S. Southeast. A pair of opposite weather extremes of the kind we’ve come to expect more and more of in a world that’s warmed by about 1.2 C above 1880s averages.

(Very extreme weather conditions settled over the U.S. on June 20. Today, Cindy is expected to bring extraordinary rainfall totals to the U.S. Gulf Coast. Video source: ClimateState.)

Record-Shattering Western Heat

Yesterday, the mercury struck a scorching 127 degrees F in Death Valley California — the hottest June 20th ever recorded for that heat-blasted lowland. Meanwhile, Death Valley-like heat spilled out over a large swath of the southwest. Phoenix fell just shy of its daily record as temperatures struck 119 F. And Las Vegas tied its all-time record of 117 F (which was set just four years ago on June 30th). Needles, Daggett and Barstow in California joined Kingman in Arizona and Desert Rock in Nevada to also break previous heat records as temperatures soared to between 111 and 115 F across these cities and towns.

(Record heat hammered the U.S. West on Tuesday spiking fire hazards, grounding planes, causing power outages and increasing the risk of heat injury. Image source: National Weather Service.)

All these severe high temperatures took a serious toll as both cities and citizens fell under blast-furnace-like conditions. In Phoenix, 43 flights were grounded. Aircraft could not generate enough lift for a safe take-off in the thin, low-density hot air. Total number flights grounded since Monday now tops 50 for the city — with more expected Wednesday when temperatures are expected to hit 118 F.

As flights were grounded in Phoenix, fires began to spark across the Southwest. Several fires ignited in Southern California including a large 950 acre blaze near Big Bear. In Utah, hundreds of people were forced to evacuate a ski town when a weed-killing torch ignited a swiftly spreading fire. And in southwest Arizona, a wildfire burned 8 structures as more than 100 firefighters rushed to contain the blaze. Firefighters across the southwest struggled against some of the most difficult conditions imaginable — extreme heat, blustery southerly winds, and rapidly-drying vegetation.

Record heat also overwhelmed grids when customers cranked up air conditioning and high temperatures put a major strain on power lines and transformers. With California temperatures climbing to historic levels yesterday, power outages were reported across Central Valley and on into the Bay area. Extreme warming of road surfaces caused highways to buckle even as hospitals prepared for a surge of various heat-related injuries from burns, to heat exhaustion, to heat stroke.

(Recent warming of ocean surfaces to well above average ranges off the U.S. West Coast have likely boosted the development of the recent western heatwave. Ocean surface warming is a signature condition of human-caused climate change. Image source: Earth Nullschool.)

A strong high pressure system and a large associated ridge aided by abnormally warm waters off the U.S. West Coast are the primary regional causes of the most recent heatwave. The pool of warm water in the Northeast Pacific — somewhat reminiscent of the Hot Blob that formed in the nearby ocean zones during 2014 and 2015 — appears to be boosting the development of upper level ridges and related surface heat over the region as temperatures climb to 10 to 25 F or more above normal for many locations. Despite recent record winter and spring rainfall for parts of the region, this new heatwave is starting to again advance drought conditions across the Southwest. Yet another hard shift in weather extremes from wet and cool to dry and hot that can likely be linked to climate change.

Cindy Ushers in Severe Flooding across the Gulf Coast

While the west scorches under extreme heat, the weather threat to the U.S. Southeast comes in the form of severe flooding. In the Gulf of Mexico, a sprawling Tropical Storm Cindy is interacting with a stalled frontal system to spike moisture levels in the atmosphere above the U.S. Gulf Coast. Already, between 3 and 9 inches of rain have fallen over parts of Louisiana, Mississippi, Florida and Alabama. But the slow-moving, heavy rain bearing Cindy is poised to dump still more.

(24 hour rainfall totals show that heavy precipitation in the range of 3 to 9 inches have already fallen across the Gulf Coast. Cindy is expected to bring even more over the coming days. Image source: NOAA.)

According to NOAA QPC predictions for the next week, as much as 8.5 additional inches of rainfall could impact already-flooded parts of SE Louisiana. And when all is said and done, the system is forecast to drop between 10 and 15 inches or more of rainfall over parts of the area. The storm is not presently expected to rival last year’s August rain event which dumped up to 30 inches over the same region. Of course, with climate change boosting rainfall potentials by warming the Gulf of Mexico and spiking atmospheric moisture and instability, the unexpected can certainly happen. Let’s just hope that’s not the case with Cindy. But 10-15 inch rainfall totals are certainly disruptive enough. And with some streets in New Orleans already seeing 2-3 feet of flooding as more storms rush in from the Gulf, this event is certainly far from finished.

Links/Credits:

National Weather Service

ClimateState

Earth Nullschool

NOAA

Tropical Storm Cindy Pushes Toward Central Gulf Coast

Hat tip to Suzanne

Hat tip to Greg

Hat tip to Tigertown

%d bloggers like this: