Monday Morning, August 21, 2017
Good viewing for the eclipse; isolated chance of showers early this week
A hot and humid airmass has returned to the Tennessee Valley this weekend! Daytime temperatures climbed as high as 93 degrees on Saturday; Sunday was even hotter, with an official high of 96 degrees at the Huntsville International Airport!
The culprit: High pressure in place over east Tennessee/western Carolina produced an area of subsidence, or sinking air; when air sinks, it compresses and heats up, and that hot air funneled down the Appalachian Mountains into the Valley.
At the same time, the high is drawing tropical air north from the Gulf of Mexico due it the clockwise flow around the system. This is why it is so humid around the Southeast, making the daytime temperatures “feel” much hotter than the thermometer would lead you to believe.
This high will stick around today, providing potentially favorable conditions for the upcoming partial solar eclipse for much of Alabama as well as Tennessee, eastern Kentucky and Georgia. Cloudy conditions may plague western Kentucky as well as the Carolinas and the Gulf Coast.
Today’s Eclipse Outlook: Eclipse viewing still looks good for the Tennessee Valley this afternoon! We do expect some thin clouds to stream in due to a disturbance near the Gulf of Mexico, plus a few puffy ‘fair-weather’ clouds. Cloud cover will be patchy though, so there’s only a slight risk of an area of cloudiness getting in your view of the eclipse.
If you are traveling outside of the area for the eclipse, the clouds will be thicker the farther northwest you go, especially from Nebraska and through central Missouri. The area from St. Louis, Missouri to Hopkinsville, Kentucky looks like fair viewing; the best view may end up just north of Downtown Nashville eastward to the Smokies. Remember to be sure you have enough fuel and that you’re prepared with food in case you get stuck in traffic for hours!
Rain returns midweek: It’s a good thing the eclipse happens today because Tuesday and Wednesday are looking much cloudier and potentially wetter as well! We’ll say goodbye to the summer heat too, as a strong cold front moves through Wednesday. We expect a round of scattered storms Wednesday afternoon before a push of cooler and drier air comes Wednesday night.
Then the end of the week will bring us a preview of fall with highs in the 80s! Temperatures could be as much as 10 degrees below average on Thursday, and our usual cool spots may drop as low as 55°F to 59°F by Friday morning.
Tennessee Valley Forecast:
TODAY: Generally good viewing for the eclipse! Partly cloudy, hot and humid with a slim chance of a shower. ‘Feels like’ around 97-100ºF at mid-afternoon. High: 93. Wind: SSE 5-10. Rain: 10%.
TONIGHT: Partly cloudy, mild, and humid. Low: 73. Wind: S 3-8. Rain: 10%.
TUESDAY: Partly sunny, hot and humid. A few widely scattered showers and storms expected. ‘Feels like’ temps around 95-98ºF. High: 92. Wind: S 6-12. Rain: 20%.
WEDNESDAY: A cold front brings clouds and a better chance of unevenly scattered showers and storms. Some rain may be locally heavy exceeding 1” in total. High: 85. Wind: WSW 7-14. Rain: 50%.
THURSDAY: Clearing early, a fresh northeast breeze brings in lower humidity and more comfortable weather! High: 82. Wind: NNE 10-17.
FRIDAY: Cooler early, still warm in the afternoon. Mostly sunny and dry. High: 86. Wind: NE 5-10.
SATURDAY: Partly cloudy. Humidity increasing, and that kicks off a few isolated showers and storms. High: 86. Wind: SE 5-10. Rain: 20%.
SUNDAY: Scattered storms, some locally-heavy downpours likely. High: 85. Wind: S 5-10. Rain: 40%.