HIGHWAY TO HEAT...
The road of weather is full of twists and turns with straight-away stretches that last for days. Sometimes you need the GPS, others you don't. Right now we're on freshly paved interstate that will take us on a pleasant path right on into the weekend...cruise control if you will. Then we head up a big hill that ends with full on heat and humidity. Of course, there's no turning back when you travel this road so enjoy the ride while it lasts, the cruise control only lasts for a limited time.
What a day we pulled out of the hat Thursday. Highs in all but the far south were in the 70s with dew points in the mid to upper 50s. Along with that, came a fresh breeze that created as nice a day as you can ever hope to see in late July. All you need to do is look at the late day temperature departures to see how sweet conditions were.
If the day's temperatures weren't good enough for you, look at the readings we'll be looking at early Friday. We start the day with the thermometer well into the 50s thanks to fair skies, dry air, and light winds.
Below you can see the pressure anomalies associated with strong surface high pressure in the center of the country. The stronger than usual high provides a pleasant feed of comfortable dry air through Saturday.
Confirming the strength of the high are the PWAT's showing water vapor going into the weekend running 30-40 percent lower than normal. Our moisture source (the Gulf of Mexico) is essentially cut-off and shut down.
Water vapor Friday evening on the GFS
Water vapor anomalies for the same time.
What this all means is that our weather remains on cruise control through the weekend. The EURO shows this for weekend highs in Davenport...these are representative of what the entire area will see. July goes out like a lamb!
AUGUST AND THE DOG DAYS OF SUMMER...
Next week brings early August, a time of year where the weather tends to be hazy, lazy, hot and humid. For many, the “dog days,” bring to mind those summer days that are so hot and steamy that even your dog lies around on the asphalt, panting. But originally, the phrase had nothing to do with dogs, or even with the lazy days of summer. Instead, the dog days refer to Sirius, the brightest star in the constellation Canis Major, which means “big dog” in Latin and is said to represent one of Orion’s hunting dogs.
To the Greeks and Romans, the “dog days” occurred around the time Sirius appears to rise alongside the sun, in late July in the Northern Hemisphere. They believed the heat from the two stars combined is what made these days the hottest of the year, a period that could bring fever or even catastrophe.
It's always a good idea to let sleeping dogs lie so I'll stop with the astronomy. What you need to know is that prolonged periods of heat are common at this time of year and that's what the tea cards are telling me happens next week and perhaps beyond. The first thing you will notice is that water vapor by the end of next week is back up near that oppressive level of 2 inches (that's the disgusting threshold we simmered in last Saturday).
The return of rich moisture and (the muggies) is a sure sign the upper air pattern is undergoing major amplification and that's very evident at 500mb, the jet stream level. Here's the NW flow aloft that is bringing our fine weather now.
Notice the difference in about a week. The heat dome is building east into the Midwest ejecting any cool air.