July 14: Storms Today and Friday, Daily Links

WEATHER

Today’s forecast is one of those in which the overview is easy, but the specifics are very challenging.  So…let’s start with the easy part: it will be hot, it will be very muggy, and scattered storms are possible.
raw

Not so fast.  Let’s take a shot at some specifics.  Before sunrise this morning, a complex of thunderstorms moved straight south from Missouri into Arkansas.  That trajectory keeps those specific thunderstorms from impacting us here in the Midstate, but the rain-cooled air from those storms doesn’t go just to the south — it spreads out to the east and west as well:
EARLIER
As that rain-cooled air advances, it pushes on the lowest levels of the atmosphere, which forces some of the air upward (think of pushing a tablecloth, and the folds that develop).  That allows thunderstorms to develop in advance of the cold air, which is what we’re seeing along the Mississippi River as I type this (8:30am-ish).
VIDEO VIPIR
So, how will those storms behave once they’ve matured (the arrow should give you a hint)?

Figuring that out is made more complicated by the fact that the forecast model data for about the last two weeks has been, well…
giphy
…yeah, that pretty much sums it up.  The forecast models have been all over the place, whether you’re comparing different models, or even different runs of the same model.  So we have to take our precious computer data with a giant grain of salt.
bFFJysJ

The RPM model brings storms from west-to-east across the Midstate from late morning through early afternoon, with the storms weakening as they progress:
RPM 10A THU RPM 12P THU RPM 2P THU RPM 4P THU
The HRRR model is a little faster, but more “robust” — it produces more widespread and stronger storms.
hrrr_2016071411_ref_nashville
But the WRF model thinks the morning storms will head off to the southeast, and we’ll have to wait until this afternoon for storms to pop up directly overhead or move in from the west.
WRF 10A THU WRF 12P THU WRF 2P THU

Confused?
Stephen-Colbert-Frozen-Jaw-Drop-Gif-On-The-Colbert-Report-Gif

Right now I lean bit more toward a midday-through-afternoon compromise — that is, I buy the RPM timing, with the HRRR strength…I’m not sure what the WRF is doing.  (It won’t rain the entire time I indicate on this map — these are the “storm windows” when the strongest storms are most likely):
PAUL STORM TIMING
That means we’ll have plenty of time for temperatures to heat up (notice the rain-cooled air, though…):
PAUL RPM 4KM Temperature
And it will feel…gross.
PAUL RPM 4KM HEAT INDEX tumblr_mnyb8tv7cP1qjjmdno1_400

The Storm Prediction Center has outlined a “Slight Risk” (level 2 of 5) for severe thunderstorms, which means that we’ll see numerous thunderstorms, a few of which could produce damaging straight-line wind gusts:
PAUL SEVERE RISK REGION
Plan on staying-weather aware this afternoon.

Tomorrow brings more of the same, but it won’t be quite as hot.  I expect thunderstorms to develop directly overhead, instead of moving in from elsewhere, and once again a few of them could be strong-to-severe.  The complicating factor here is that today’s storms could re-arrange the atmosphere and alter tomorrow’s storm chances significantly:
RPM 1P FRI RPM 3P FRI RPM 5P FRI

Right now the SPC is showing a “Marginal Risk” (level 1 of 5) but I wouldn’t be surprised if that’s bumped up to a Slight Risk as well in subsequent outlooks.
PAUL SEVERE RISK REGION 2

The storm chances will dwindle over the weekend — this time of year, if rain chances go down, temperatures will go up.  This weekend will be no exception.
WSMV 7 Day AM

Finally, I’m just going to leave this here, because it’s delightful.
colbert-6.nocrop.w529.h309

LINKS

I spent all of my “link searching time” early this morning tracking down Colbert GIFs.
SWKHjgJ

But now the nerd-links are up!
15679-Stephen-Colbert-Kermit-The-Frog-Excited-Gif

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About paulheggen33

Morning meteorologist for WSMV-TV in Nashville.
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