May 20: Afternoon Storms, Daily Links


We had a beautiful sunrise this morning…if you weren’t up that early, here’s what the pre-dawn hours looked like over downtown Nashville:

However, the weather won’t be ideal all day — we’ll see increasing clouds by noon, and increasing rain chances this afternoon into this evening.  As I usually do, I’ll show you some Futurecast snapshots of what we expect the radar to look like this afternoon, but first a little background…as I’ve mentioned before, we have a few different versions of the computer models we can feed into Futurecast.  One of the ways we evaluate which one to use is based on how well they initialize — that is, how well they depict what’s already happening.  This morning’s version of the RPM model initialized very well — check out what it showed for 7am, compared to the regional radar view just after 7am:

That kind of agreement between model and reality makes me reasonably confident that this version of Futurecast has a pretty good handle on how things will shape up this afternoon and this evening.  By noon, we expect showers and thunderstorms to approach the Tennessee River, with increasing clouds across the rest of the Midstate:

That first wave of showers and storms will be running headlong into the dry air that moved into our area yesterday.  That will help to weaken and dissolve the first round of showers through mid-afternoon…maybe.  If those storms fall apart, another area of thunderstorms will develop and head in by late afternoon; if the first round holds together, the rain chances will arrive a little earlier than what Futurecast depicts here:

The second round of storms is the wild card — if it forms, it could be a little stronger, especially south of I-40 and west of I-65.  Keep in mind, even when we’re pretty confident in how the computers are depicting things, there’s always some difference between expectation and reality, so this isn’t a guarantee of when and where storms will be strongest and most widespread…just a good estimate:

By late evening and overnight, the second round of storms will diminish to showers as it moves into eastern Middle Tennessee:

The strongest storms this afternoon and before sunset this evening could prompt a couple of severe thunderstorm warnings, but overall our severe weather potential is very low.  The Storm Prediction Center has included southwestern Middle Tennessee in a “Marginal Risk” for severe weather, the lowest rung on the severe-weather ladder:

Specifically, they means they estimate a 5% chance of 60mph winds or 1″ diameter hail within 25 miles of any point within the Marginal Risk area:

It’s always a good idea to stay weather-aware during the spring and early summer around here, but at this point I’m minimally concerned about our severe weather potential today.  IF any watches are issued I’ll post them on social media.  ALL severe thunderstorm and tornado warnings for every county in our viewing area are posted to my Twitter feed — do NOT rely on Facebook for time-sensitive weather information.  Social media links are at the bottom of this post.

Quickly looking ahead to the holiday weekend, it’s looking like Saturday will be the ideal day for outdoor activities.  Sunday and Monday will still be warm, but will also bring increased humidity.  That mugginess will be the fuel for scattered midday and afternoon thunderstorms — only a 30-40% chance, but that’s still high enough that I’d recommend being flexible with any outdoor plans.



Lots of weather-related stuff today, plus some other space- and science-related tidbits…

  • Since there are storms in today’s forecast, this seems relevant: the five different ways lightning strikes people.
  • Despite an early start to the 2015 Atlantic hurricane season (tropical storm Ana a couple of weeks ago), don’t expect a busy season overall.
  • Can those seasonal hurricane outlooks be trusted?  Well…kind of.
  • 20 things you may not have known about clouds.
  • The drought in the western United States is having widespread impacts, including on the Colorado River.
  • The stated goal of climate-change mitigation effort is to limit total warming to a global average increase of 2 degrees Celsius.  But a more reasonable estimate is that we can expect twice that much by 2100.  (Incidentally, 3 degrees is thought to be the tipping point where climate change becomes a runaway effect.)
  • Space news: an innovative new spacecraft is hitching a ride into orbit today.
  • Laboratories around the world are beginning the search for evidence of gravity waves.
  • A new study finds that concussed NFL players actually exhibit entirely different brain structure later in life.

Social media links

Twitter: @WSMVweather, @PaulHeggenWSMV, @WSMVLisaSpencer, @WSMVDanThomas, @WSMVNancyVanC, @NWSNashville

Facebook: 4WARN Weather, Paul Heggen WSMV, Lisa Spencer, Dan Thomas WSMV, Nancy Van Camp WSMV, NWS Nashville

About paulheggen33

Morning meteorologist for WNCN-TV in Raleigh.
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