Catching a Break From Heat
We rarely associate July with comfortable weather in Oklahoma, so when it happens, some might say we're just livin' right. Our four-month stretch of below-normal temperatures ended last month. June was 1.5° above average. July on the other hand is off to a nearly record-cool start. I took a look back at the past 15 years and no year had a cooler first week in July than we have in our forecast. In fact, the first week in the coolest July recorded in Tulsa (1950) was still warmer on average than our week ahead! Maybe it's less "livin' right" and more something we deserve after the past two summers of searing heat.
It's an unusual and persistent pattern that has brought about this great change from last week's heat to this week's September-like readings. That heat went west and got worse. An oppressive and record-setting heat wave is taking place from Arizona to Idaho all thanks to a major pattern shift. The first attached map is what that pattern looks like now on a weather map. It features an anomalously deep trough in the eastern US with just as large of a ridge over the West. The pattern is blocked at the moment with these two features locked into place. A continuous stream of Gulf moisture along the eastern seaboard is bringing flooding rainfall thanks to the trough. Ridging in the jet stream out west promotes mostly clear skies and heat to build day to day. That monster ridge puts places like Phoenix, Las Vegas, Boise, and Death Valley under the grip of the relentless heat and drought. Temperatures soared to a record-setting 129° in Death Valley, just 5° shy of a world record for air temperature. Monday will likely be just as hot.
In between these brutal extremes lies Oklahoma. Northerly flow gives us a continued supply of dry, unseasonably cool air. That pattern stays locked in place through Independence Day with very little change. Thus, your fireworks and BBQ forecast couldn't be nicer. Temperatures will be in the 80s for highs and upper 50s and 60s for lows with a light breeze and passing clouds. An isolated shower may occur, but shouldn't seriously dampen anyone's plans.
That trough does break down a bit by the weekend and the heat lets up just a bit out west. Essentially, we see some equalization as temperatures gradually climb here with a gradual increase in moisture. That might allow for a few showers and storms this weekend as the pattern makes the shift to a more zonal jet stream flow.
My thoughts and prayers go out to those battling wildfires in the awful heat in the Southwest, especially in light of the tragic death of so many firemen in Arizona. It's a good reminder for us in Oklahoma to use good discretion when lighting fireworks so we don't put our own firemen at risk to battle additional fires. Even though the weather is mild, we've been dry for quite a while now. Our vegetation is drying out and becoming more flammable. Be careful, but enjoy the wonderful weather and great holiday ahead this week!