It’s a hot start to the week across the West with temperatures running 5-10 degrees above normal beneath a powerful upper level ridge but an upper low off Southern California will head inland and push up into the Northern Tier over the next few days increasing a ‘dry lightning’ threat across the Great Basin and Rockies. While this feature heads NE, a Pacific low will push into the Pacific Northwest, carving out a trough, cutting heights over the Southwest.

Both low pressure features will force the broiler plate ridge east after baking the Desert to 126 degrees this past weekend. The focus of heat transfers into the Rockies and Plains with 100s spreading into the Southern and Central Plains while the Desert sees temperature return to normal levels for the time of year. Salt Lake City should see it’s first 100 this afternoon along with Dallas while it should get close in Denver. The majority of this week will be hot from Houston to Valentine, Neb.

A cold front associated with a low pressure system pushing through the Great Lakes is producing a messy start to the workweek from New Orleans to Albany, NY. Heavy showers and embedded thunderstorms will affect many, forcing office workers heading out for lunch, to run from building to building as they dodge showers and storms.

Here’s the ECMWF surface/precip chart at 18 hours and you can see the plume of moisture over the Eastern Seaboard this afternoon while ridge builds east into the Plains.

The upper low seen spinning off Southern California over the weekend which enhanced the marine layer, shrouding the beaches and holding the daytime maximum at 63 in San Diego will track NE over the next few days increasing the dry lightning threat over the Great Basin and Rockies.

The ‘dryness’ of the upper low, currently positioned over Southern California is catching the attention of the meteorological community. Dr Greg Forbes of The Weather Channel said he has never seen as dry of an upper low.

Check out this water vapour image capturing the upper low this morning…

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Here is the 500mb ECMWF chart out at 6 hours and you can see the upper low trimming the heat over much California. Sacramento reached a record 108 Saturday and yesterday it only reached 79, that’s 7 below normal thanks to an enhanced delta breeze. Highs return to the upper 90s, low 100s over the Colorado and Mojave Desert rather than 110s. 70s, 80s for the Central Valley. The low is already lighting up the skies east of San Francisco this morning, particularly over the higher terrain which should help keep warming at a minimum in areas with downdrafts but this increases an already severe wildfire risk with little rain expected over the next 7 days.

Back to the East and not only is there a flood risk with the heavy rains today over the Mid-Atlantic but there is a slight severe weather risk too from South Carolina to southern Pennsylvania thanks to the hot air on the backside of the front and a strong south/southeast flow rising north.

AccuWeather’s Flood Threat Area

AccuWeather’s Outlined Strong/Severe Risk

As we progress through this week the upper level ridge will be supressed to the south due to eastward tracking lows over the Northern Tier but there’s no stopping the hot air from sliding into the ‘Sunbelt’. The hottest air of the year is en-route to Atlanta, Columbia and Charlotte with the first 90s of the year.

Here’s the 500mb by 36 hours or tomorrow and notice the core of the ridge now centred over Oklahoma and North Texas with heights of 592dc. This should push 90s into Atlanta while it should be the second day of 100 in Dallas. Notice heights considerably lower over the West with that upper low (currently over SOCAL) riding the ridge over Utah and enhancing the dry lightning threat.

By 48 hours and the broiler plate ridge is baking the southern and central Plains with 100s for Dallas and Oklahoma City while it may push 95 in Atlanta and Charlotte.

By 72 hours or Thursday the ridge continues to strengthen and spread it’s 592dc height line. We may see 3-4 straight days of 100+ in Dallas, OKC up to Wichita. The heat may well peak in Atlanta and Charlotte with highs of around 95. Note the trough carved out over the West Coast and upper energy streaming over California from the SW.

I also want to draw your attention to the Northeast and Mid-Atlantic. While it may be cooking over the Southeast, it won’t be further north with a lot of rain and storminess. The Northeast and Mid-Atlantic shall be beneath a kind of ring of fire pattern through this week with a lot of rain possible.

Check out the 120 hour total precipitation chart.

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