November 28: Wind, Rain and Severe Storms, Daily Links

WEATHER

The forecast is a good news/bad news scenario for the next couple of days:
– GOOD NEWS: The weather cooperated for holiday travel yesterday!
– GOOD NEWS: Two chances of significant rain headed our way over the next few days.
– BAD NEWS: At least some severe weather threat associated with each rain chance.

Warm and windy conditions will prevail before the rain arrives — temperatures will reach the mid to upper 60s this afternoon:
monday-hihgs
It will be a very breezy day overall, with sustained winds 20-30 mph, and wind gusts over 40 mph possible…the yellow-shaded areas on this map indicate where wind gusts are likely to be over 35mph before the storms arrive this evening:
hrrr_gust_se_13
That’s why a Wind Advisory is in effect from 9am until midnight:
paul-watch

While the strongest storms will move in this evening, your rain chances aren’t zero during the day — the best chance of spotty showers will be west of I-65 this afternoon, as the RPM model’s radar simulation shows:
rpm-12p-mon rpm-2p-mon rpm-4p-mon
The stronger storms will approach from the west by late this afternoon, moving across the Midstate this evening:
rpm-5p-mon rpm-6p-mon rpm-7p-mon rpm-8p-mon rpm-9p-mon rpm-10p-mon
The HRRR model is in pretty good agreement with that timing:
hrrr_2016112812_ref_nashville
Still, there’s always some uncertainty when it comes to specific timing — the atmosphere will do what it wants, which means we could see a slightly earlier or later arrival.  Smoothing out the differences between the various forecast models, here’s when I expect the strongest storms to arrive:
paul-storm-timing

Our severe weather threat this evening is another good news/bad news type of thing…
– The good news is that the instability needed to fuel explosive storms will be very low…almost zero, in fact.  The dry air that’s been hanging out over the Midstate for so long will really help us out — even the strong southerly winds won’t be able to drag enough humidity up towards us to destabilize the atmosphere.
– The bad news is that there will be a TON of wind energy in the atmosphere overhead — the statistics that measure wind shear are absolutely off the charts.  Wind speeds just one kilometer off the ground (roughly 3000 feet) are going to be around 90 mph!  The heavy downpours with the main line of storms could drag some of that wind energy down to ground level, which is why damaging straight-line winds are the main cause for concern:
paul-severe-risk-graph
The tornado threat isn’t zero either, but the greatest tornadic threat will take shape to our southwest, where a more-favorable combination of wind shear and instability will be present.  That’s where the Storm Prediction Center has outlined an “Enhanced Risk” (level 3 of 5) of severe thunderstorms:
paul-severe-risk-region-1
For the Midstate, it’s a “Slight Risk” (level 2 of 5) west of I-65, with a “Marginal Risk” (level 1 of 5) for the rest of us.  Plan on staying weather-aware this evening — if any warnings are issued, we’ll pass them along on-air and on Twitter (links at the bottom of this post, after the nerd-links).

The daylight hours on Tuesday will feature lots of sunshine and near-record highs:
tuesday-highs
Another rain chance develops and moves in from the south Tuesday night:
rpm-12a-wed rpm-2a-wed rpm-4a-wed rpm-6a-wed
Once again, the most-favorable severe weather ingredients will come together to our south, but most of the Midstate is included in a “Marginal Risk” for severe storms:
paul-severe-risk-region-2
I’m actually more concerned about Tuesday night’s severe potential — while the wind energy won’t be as substantial, it will still be sufficient…and there will be at least some instability in place as well.  That doesn’t mean you need to hide in your safe place until Wednesday morning — it just means we’ll be keeping a very close eye on things.

At least these storms will be bringing some much-needed rainfall to the Midstate!  Total estimated rainfall in the Midstate through midday Wednesday shows around 1″ in southern Kentucky, around 2″ in Nashville, and 3″-4″ in southern and eastern Middle Tennessee (the areas that need it most!):
paul-rpm-12km-precip-accum

Once the rain departs Wednesday morning, the weather will settle down for the rest of the work week, with near-normal temperatures for the first couple days of December:
wsmv-7-day-am
Another chance of rain heads our way for the weekend, but I can’t go higher than 50-50 for the chances just yet.  The European forecast model (generally more accurate) shows a very good chance of rain Saturday night and Sunday…
ecmwf_apcp_f156_us
…while the American forecast model keeps most of that rain pushed down to our south:
gfs_op_apcp_f144_us
Time will tell!  We’ll keep you updated throughout the week so you can plan your weekend accordingly.

 

LINKS

The daily roundup of science news and other nerdiness is back, after a little holiday break…

——————–
Social media links

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

Facebook: 4WARN Weather, Paul Heggen WSMV, Lisa Spencer, Dan Thomas WSMV, Daphne DeLoren, NWS Nashville

Instagram: PaulHeggenWSMV

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About paulheggen33

Morning meteorologist for WSMV-TV in Nashville.
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One Response to November 28: Wind, Rain and Severe Storms, Daily Links

  1. Tom Nichol says:

    I sincerely hope you read my apology for the tome of my earlier reply the other day. As I mentioned then, I do realize that you’re under pressure to get a lot done in a short time, and I DO appreciate your efforts and those of your colleagues!

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