April 27: Active Weather Pattern, Daily Links


Last night’s rain is moving off to the east, and the sun will break through later today, allowing temperatures to reach the low 70s for highs this afternoon:

Dry and pleasant tonight, with lows in the low 50s:

The heat and humidity will both increase on Friday.

High temperatures will top out in the mid 80s Friday afternoon:

Dew points will climb into the 60s, which isn’t where we want to be on the Muggy Meter:

The humidity will be the fuel for the potential of strong to severe thunderstorms along and north of I-40 Friday evening and overnight.  This is the part of the forecast that’s going to drive me insane for the next 36 hours, because there are so many uncertainties.
WHAT WE KNOW: The atmosphere will be very unstable, and there will be enough wind energy overhead to make all types of severe weather possible.  Any storms that develop are likely to become severe.
WHAT WE DON’T KNOW: Will storms actually develop?  We won’t get severe storms if there aren’t any storms in the first place!

So let’s unpack that a bit further…unfortunately, the forecast model data is all over the place — some keep us dry, some develop widespread thunderstorms.  The most-useful tool in a situation like this is an ensemble model: a model “collection” that represents the output of multiple individual models.  The Storm Prediction Center’s Short-Range Ensemble Forecast (SREF) is exactly that, and it’s showing a 90% chance that the atmosphere will be “ready to go” if any storms develop (technically, this is the probability of the Supercell Composite Parameter being over 6 Friday evening):

But here’s the good news…the SREF is only showing a 20-30% chance of storms firing up to take advantage of that unstable environment:

So we’ll have all the ingredients for severe weather in place, but without much of a trigger to get it started.  The SPC has outlined an “Enhanced Risk” (level 3 of 5) of severe weather that includes our northwestern counties, roughly coinciding with the area where storms are more likely.  The “Slight Risk” around Nashville indicates the conditional nature of the threat (i.e. lots of “ifs”):

You should still plan on staying weather-aware tomorrow evening — I’m certainly hoping the lid stays on the atmosphere overhead, but it’s a volatile-enough setup to warrant your attention.

The rain should be gone by Saturday morning and the start of the marathon in Nashville, but that’s yet another set of ifs and buts and questions and headaches.  Some of the evening/overnight storms could hold together into early Saturday morning — most of the computer models don’t think so right now, but I’m nervous about it.  If you’re running or spectating, plan on some rain to at least be in the area to start the race…hopefully we can drop that from the forecast as things come into better focus:

This is the RPM model’s radar simulation for Friday evening through Saturday morning, but keep in mind that this is ONE version of ONE model.  The pattern shows why I’m nervous both about our severe weather potential to the northwest of Nashville, AND about the marathon forecast in Nashville itself:

At this point, that’s literally the only model showing rain lingering for the start of the marathon.  There’s a LOT more data we’ll be sifting through over the next few days, so stay tuned for updates.

What I’m more confident about for Saturday is that it will be very warm and steamy throughout the day, with highs reaching the upper 80s:

More strong to severe storms will be possible late Sunday.  The level of that threat will depend on the timing — afternoon and early evening are bad, late evening and overnight would better…not great, but better.  We’ll get a better look at some data for that storm system beginning tomorrow.



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On and Off Storms

Feeling like summer today with plenty of sunshine and warm temperatures.  Nashville reached 83 degrees, the average for this time of year is 73 degrees. Rain and thunderstorms are moving in overnight as a front pushes into Middle Tennessee.  At this writing there is a Severe Thunderstorm Watch for West Tennessee until 9pm. But as you can see on Channel 4 Live Doppler Radar there are no showers in Middle Tennessee yet.


Here’s a general overview of the time of the storms moving into Middle Tennessee.


Check out the latest Futurecast depiction that shows some weakening of the storms as they move eastward.

I do think the greatest threat will be from damaging wind, perhaps some hail in northwest Middle Tennessee. The rain does move out early tomorrow.  We’ll have clearing and cooler temperatures in the afternoon.  The high will be closer to average. The rain will help reduce pollen.


Friday most of the day should be dry, but the conditions become more favorable for thunderstorms late in the afternoon with high wind and hail possible.  Some of those storms could be strong to severe.

Saturday will be warm and humid, but it will still be unstable, so we can’t rule out some isolated thunderstorms.

Sunday brings our greatest chance of severe thunderstorms as a strong front moves in.  I am also concerned with the potential for flooding with this round of storms.  Over the next several days many areas in Middle Tennessee could pick up 3-5″ of rain.


I’ll have an update on Channel 4 News at 10pm.

Lisa Spencer


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April 26: Bumpy Weather Ahead, Daily Links


Temperatures will warm up quickly today with partly cloudy skies overhead — highs will reach the low to mid 80s this afternoon:

That’s warm, but not record-setting…today’s record is 91, and record highs through the weekend are around 90 as well.  If you’re heading downtown for the Predators’ plaza party, the weather is looking cooperative!

A good chance of showers and thunderstorms will move in from the west late tonight…the RPM model’s radar simulation shows the storms will be weakening as they move in:

Despite that weakening, we’ll still be watching for a chance of severe weather.  The Storm Prediction Center’s outlook shows the greatest severe weather threat in southern Arkansas and northern Louisiana, tapering to a “Slight Risk” (level 2 of 5) along the Tennessee River late this evening:

The rain will be gone early Thursday, with temperatures bouncing back to the low 70s tomorrow afternoon:

Another chance of storms will develop late Friday, but there are still a lot questions about that one — there will be plenty of warmth and humidity to make the atmosphere unstable, but not much of a “trigger” to get storms started.  I’m going with a better-than-50/50 chance Friday evening, but I wouldn’t cancel any outdoor plans yet — just be flexible with those plans.  The SPC is already showing a “Slight Risk” (level 2 of 5) of severe weather Friday, with an “Enhanced Risk” (level 3 of 5) in our northwestern counties:

It’s certainly possible that the greatest threat will eventually take shape farther to our northwest, but the European forecast model (one of the most-accurate) is still showing widespread storms in the evening.  Stay plugged-into the forecast for potential changes, because this one could go either way.

I think the storms will be gone by the time the marathon starts early Saturday morning, but it’s going to be warm and steamy.  Temperatures will start in the upper 60s, and will already be near or above 80 by the time most of the runners are finishing up:

Dew points will be in the 60s, which is firmly in “yuck” territory on the Muggy Meter:

Yet another chance of storms will move in by late Sunday, and that one looks like it will bring the greatest potential for severe weather — both the American GFS model and the European model are pointing toward a significant severe weather threat.  That said, it’s several days off, so there’s time for the pattern to change:

Once Sunday’s storm system moves through, the weather will settle down for a few days.



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Soaking up the Sun

Bottle this one up…so beautiful! Things started off on a foggy note, but by afternoon sunshine was abundant.  The high reached 77 degrees, just 4 degrees before the average.  High pressure is responsible for this beautiful blue sky and more is on the way tomorrow.

WSMV Social Panel Pictures Tunnel


Wednesday will be even warmer with the high reaching 85 degrees. An approaching front swings in late tomorrow night with rain and some thunderstorms.  Some of that wet weather will linger into Thursday morning. Right now it does not look to be severe.


Thursday afternoon some clearing takes place.  That is good news for Surviving the Storm which is scheduled for Thursday night at 7pm at LaVergne Middle School. This will be the last Surviving the Storm of the spring.  I hope you’ll come join us for a meet and greet, games, door prizes, experiments and some life saving information.


Friday a warm front will move back across the mid-state, this will bring more rain and thunderstorms to the area.  There is a lot of uncertainty with this system.  Right now, it doesn’t look like all the severe ingredients are coming together, but we’ll keep you updated.


Saturday is set to be a warm and muggy day…not that great for runners in the Rock and Roll Marathon.  Organizers have moved the start time up to help. The high will be in the mid 80s.


We are not quite done with Flooding issues.  There are still several warnings and advisories.

Flood Warning for the Tennessee River at Savannah and Dick River at Centerville.

Flood Advisories for the Stones River at Donelson, Duck River at Hurricane Mills and the Tennessee River at Clifton and Perryville.


Join me for an update on the weather on Channel 4 News at 10pm.

Lisa Spencer




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Winner of a Tuesday in Store

Even though many of us have had to deal with some fog this morning, it’ll be tough to beat the weather this afternoon!

Outdoors now, it’s bright and sunny over Nashville — just beautiful!


Fog continues to hold on though in some spots.  Two of the foggiest areas are central Sumner County and central Putman County…



4WARN Live Doppler Radar in fog tracker mode shows (as of 8:50am) how the fog continues to hang on there….and in most areas in between.


Temperatures are on their way up nicely, especially where the sun is shining!


Today, sunshine will rule, far different from the weekend and yesterday for that matter.  Check out the Sunshine Outlook below for today and for the several days that follow:


Temperatures will reach early-mid May levels this afternoon, with very little wind.  It’s the lack of wind that will help today be such a nice one.!


Highs across the rest of the area will be similar to Nashville’s.

DT 4 RPM 12KM Temperature2

SO…rain will hold off today.  It’ll also steer clear of the Mid State tomorrow.  However, tomorrow night, a dissipating batch of showers and storms will move in from the west.  They’ll be outrunning their support, so the weakening trend will continue as they reach Nashville.  While there may be a strong storm or two over our far western counties before midnight tomorrow, most areas will just have some rain as they pass on by.  Any left over showers will exit the area by noon on Thursday.  SO…Thursday afternoon will turn pleasant again, with highs in the 70s.

Coming up today on Channel 4 News at Noon, we’ll focus more on what we expect this coming weekend.  We hope you join us then!


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Break from the Rain

After a wet weekend, it’s wonderful see a few peeks of sunshine today. There is more of that to come tomorrow and Wednesday.  With the clouds today, temperatures were slow to rise, but Nashville did reach 70 today.  The average for this time of year is 73.

Even though the rain has stopped, there are still some Flood Warnings and Advisories.

A Flood Warning remains along the Tennessee River at Savannah and the Duck River at Centerville.  They are highlighted in Green.

Flood Advisories remain in effect for the Tennessee River at Perryville and Clifton, the Duck River at Hurricane Mills and Columbia and the Stones River at Donelson. Those are in the blue below.


As the clouds break up more tonight, there will be a beautiful sunset for many of us.  I hope you send in photos. Post them on Facebook Lisa Spencer, or Twitter WSMVLisaSpencer or email them to pix@wsmv.com.

With all this left over moisture, fog will develop overnight.  A Dense Fog Advisory has been issued for early tomorrow morning.  Give yourself a little extra time tomorrow to drive to work as visibility could be down to 1/4 mile in spots.


Tomorrow will be beautiful as sunshine takes over and the temperatures soar to near 80 degrees.  Wednesday warms even more to 85, but clouds will increase in advance of the next system.  By late Wednesday night into Thursday morning the rain and thunderstorms will be back.  Again on Friday more rain and some thunderstorms rumble through.  I know weekend rain is not what anyone want to hear, but there will be some.


Come one, come all!  the last Surviving the Storm for the spring is this Thursday in LaVergne.  We’ve got a great show planned with some audience participation experiments and games planned. Snowbird will join us with some nice prizes too.


I’ll have the latest on the forecast tonight on Channel 4 News at 10pm.

Lisa Spencer


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Nicest Day of the Week Just Hours Away

The nicest day of the week is just hours away!  In the meantime, many of us are stuck under this pesky deck of clouds.

Here’s how it looks from the satellite, in outer space…


The underside of this deck of clouds shows many holes, at least around Nashville.


Gradual clearing will continue into this evening.  Notice how FUTURECAST is showing the night will unfold.

Because of all the recent rain and the fact that the wind will go calm overnight, areas of dense fog are likely to form by dawn.  SO…if you’ll be part of tomorrow morning’s commute, be sure to allow a few extra minutes to deal with any slow spots on the roads.

DT Morning Fog

Speaking of rain, so many of you have asked me how much rain we received this weekend  That’s a great question!  It seemed like it would never quit.  The National Weather Service in Nashville posted this graphic a short time ago on their website.  It shows rainfall since Thursday night.


Many of us however get dumped on last Tuesday night, too!  SO….I created the image below, from Doppler Radar rainfall estimates, which shows how much fell over the last 7 days.  The encircled area indicates where at least 5″ (or very close to that) fell.


After tomorrow morning’s fog burns off, we’ll be smooth sailing into the afternoon!  The wind will be light, so all in all it’ll be a very pleasant day.  In fact, I’m calling it the nicest of the next seven!

WSMV Day Planner Half

Since tomorrow will be the nicest for a while to come, you can infer that means more rain, thunderstorms, and clouds are in store through the rest of the week and upcoming weekend.  In fact, over the next week, we expect at least a few weather systems that will make for heavy downpours and storms.

Coming up today on Channel 4 News beginning at 4pm, we’ll delve deeper into when and where those rounds of storms will occur.  We’ll also look at which days will feel like mid summer, and which will have rather cool nights.  Join us!


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