Rain Today, Storms Possible Monday, Stronger Storms Possible Wednesday

An east-west line of storms will continue to impact the area.

As expected, more rain north, less to the south. This activity will begin to taper off later this evening, with only spotty showers tonight. Washout potential is low but a good soaking is expected.

Stronger System Monday (Storms?)

More rain and possibly some storms are possible Monday morning.

Models agree on the morning start but not the exact time.

GFS has an early morning (6-9AM) start

Euro Model has a late morning (9AM-Noon) start.

This timing difference will determine just how potent the storms are. Early morning start = storms that lack instability due to insufficient heating. Late morning start/closer to afternoon = storms that tap into a little more instability.

At this point (subject to change) even if storms start closer to the afternoon, instability will still be too weak to be concerned about. Something we are watching closely giving the very strong shear values expected…

There will be plenty of shear with the gradient over the area, but lapse rates and surface instability will be lacking and likely be the limiting factor for any strong to severe thunderstorm development.

NWS AFD 03-13-2021

Storms with plenty of bark but a weak bite.

SPC has us outlined in a “general thunderstorm” risk Monday:

Outlook valid 7AM Monday-7AM Tuesday

Rain totals will be more than Saturday’s activity. 0.5″-1″ for most.

Even Stronger System Wednesday (Severe Potential?)

This system is one that bears close watching.

SPC already has highlighted a 15% ring of severe storms within 25 miles of any given point.

This includes ALL of Middle and West Tennessee as well as much of the Deep South.

By Wednesday, a more substantially unstable environment, encompassing a large area, is likely as moist Gulf airmass stream northward, beneath rather steep lapse rates advecting eastward… While a more concentrated area or areas of severe weather may evolve Wednesday, those details will require discernment in subsequent outlooks.

SPC Discussion 03-13-2021

Details are fuzzy, conclusions shouldn’t be drawn, clickbaity, fear-hungry posts should be avoided.

Higher-resolution models are not in range. Once we get past Monday’s event, we will have a much better handle on what Wednesday could bring.

More details to come in future blogs.

Three Waves of Rain (Storms?): What We Know (And Don’t Know)

#TBT

https://twitter.com/StormyClaussen/status/1370008547854057479?s=20

Those “warm and happy thoughts” will lead to high near 80 today.

Warmer temps will provide more energy for showers to develop Thursday afternoon. HRRR Model predicts most of the showers will stay to our north.

The further north you are, the better your chances of getting your backyard wet (Joelton-Goodlettsville). This activity should be rather light with no severe worries.

Rainy Front Sinks In Friday-Saturday

Better rain chances come Friday afternoon/evening into Saturday morning. Euro Model shows the activity to our north dip down into the northern half of the state.

GFS agrees with similar rain chances and amounts. This activity too won’t be especially strong or heavy.

Rain chances should diminish as we progress through Saturday with everything ending by the sunset.

Total Rainfall amounts through the weekend will vary drastically across Davidson and Williamson Counties.

Joelton in northern Davidson County could receive up to 0.75″ whereas Thompson’s Station in southern Williamson County may only see 0.25″.

More Significant System Monday

This will be a strong/severe thunderstorm event in Arkansas on Sunday. But what will it be when it gets here Monday? Pretty weak, probably. Models show it showing up Monday morning when our storm-fuel will be gone.

Along with shower chances, there maybe enough instability across our area after midnight Sunday night through Monday morning to support isolated thunderstorms.

NWS AFD 03-11-2021

Current thinking is that instability will be lacking. Thus limiting the severe potential. As always this could change as newer information becomes available.

If the line delays and arrives Monday afternoon – giving time for instability to build to power up storms – we may get some thunderstorms with a damaging wind risk. From the Storm Prediction Center:

A remnant of the squall-line may be ongoing ahead of the front in the morning. This line may re-intensify by midday as instability increases. The current thinking is that an isolated wind damage threat will develop during the afternoon from middle and eastern Tennessee southward into Alabama.

SPC Day 5 Outlook, 3/11/21

Current Panic Level:

Yet another storm system is due in here towards mid-week. Thunderstorms could be involved with that one too. Deets are fuzzy and speculation is unhelpful.

More on that in upcoming blogs. Until then, Happy Thursday!

‘Severe CLEAR’ For A While

A chance to connect with us…

Register here for a discussion with the Nashville Severe Weather team tonight at 5:30pm hosted by the National Weather Service, Nashville as a part of severe weather awareness week.
CLICK HERE TO REGISTER

Sun and Warming Temps

A ridge of high pressure to our south will provide sunshine and warming temps through next weeks. Low to mid 70s are possible by Thursday-Friday.

Models are having a difficult time dechipering when our next rain chances will be.

A low pressure center looks to develop over the southern plains and then push eastward and penetrate the surface high late next weekend or early next week. Until then, our rain chances appear minimal.

NWS Nashville AFD 03-06-2021

I think you can bet on all of next week being mostly dry and mild.

Since we are in a calm pattern for a while, it is a good time to brush up on those severe weather plans. Below are some important reminders for you and your family.

#bepreparednotscared

Sorting Through Uncertainty about Rain vs Ice Thursday and Snow vs Nothing This Weekend

A drizzle or two is possible Tuesday and Wednesday but most of the precip should pass north and northwest of us. Below is the forecast for total rainfall Tuesday through Wednesday night at midnight:

Total Precipitaion Through Midnight Wednesday Night

Cold, Steady Rain Thursday

A heavier, steady rain event is expected here Thursday, pushed along by a cold front. It’ll be a cold rain.

Probably a cold rain.

“Probably.”

What about wintry chances?

In northern zones, temps will cool near or below freezing , bringing chances not only for a rain/snow mix but even some freezing rain/sleet if the GFS pans out.

NWS Discussion 02-08-2021

Models have been all over the place with this system. Rain, snow, sleet, ice, nothing, leprechauns, shape-shifters, and twelve toes lemurs among model output over the past several days. Clickbaiters delight!

The GFS model referenced above has a rain to wintry mix transition Thursday.

The Euro model disagrees. Look at the thin blue line in NW Middle Tennessee. That line represents surface freezing temps. There we may see freezing rain or sleet. But locally, only a really cold rain.

Euro Model Precipitation Through 6PM Thursday

Current thinking (as always subject to change) is that we just get a cold rain. Forecasters are leaning toward the Euro model.

The NBM (National Blend of Models) seems to resolve the GFS and Euro models by taking some of the GFS, some of the Euro, plus other data, to generate a compromise solution:

Draw few conclusions. Models love changing their minds, especially these medium range global models that run at a lower spatial and temporal resolution than shorter range models. Global models only outline events, they don’t detail them, like the difference between reading the cover of the book and reading the book itself.

We are always be a bit leery of any potential ice accumulation: even 5 hundredths of an inch can cause travel problems.

Now, that said, we are not worried about anything just yet. A few degrees on the surface and aloft can switch an event from a relatively harmless rain to a snow, sleet, or freezing rain event. To get the worst possible result — ice — very specific ingredients need to line up exactly right. Ice happens, but it’s rare, and there is no data right now to sound alarms.

Suppose the worst happens — rain falls through warmer air aloft, and hits subfreezing air at the surface and freezes late Thursday night into the early morning hours Friday — that ice would be expected to melt as temps again rebound above freezing Friday around late morning.

The weekend is also interesting. The Euro Model thinks we will be much warmer than the much colder GFS model. The GFS brings in a bonafide accumulating snowstorm Saturday night, whereas the Euro model is bone dry. Place your bets. The smart money is usually on the Euro.

Cold is the Word, More Rain This Weekend

It’s cold this morning.

A good reminder that we are in the core of the winter season.

Fortunately, we stay dry through Friday.

Weekend System

We should start Saturday on a dry note before this system moves in.

A surface low over Texas will move eastward throughout the day.

This will bring an increase in rain, especially during the evening/overnight hours Saturday Night.

Current thinking from the Euro Model:

It has a few light showers in before sunset with the bulk of the heavy rain after sunset, lasting until sunrise Sunday morning.

Both severe weather and flooding look very low with this system.

This system has all kinds of shear but instability is limited… QPF not excessively high and it is a fast-mover. We will get a good rain but flood potential is low.

NWS Discussion 01-28-2021

Speaking of rainfall amounts…

Think 0.25″- 0.5″ is a good bet with locally higher amounts possible.

Looking Ahead

We enter another dry period before our next system: Wednesday-Thursday

Cold Rain or Snowflakes Wednesday Night

Most of the daylight Wednesday will be dry.

Around dinnertime or a little before, precip should be moving in. No storms. Cold rain most likely, and maybe some snow.

Euro Model (below) shows *maybe* a light rain/snow mix.

HRRR Model shows something similar, but with even less moisture.

GFS is showing up to an inch on the Plateau but other models showing less. Overall it looks like we could see trace amounts, with half inch or so at higher elevations.

NWS AFD 01-26-2021

Current thinking is that this will be a “plateau gets all the fun” event.

Any flakes we get should melt immediately upon nestling on the ground.


We dry out to end the week with next chance of rain being Saturday. This looks to be a heavier event.

0.5″ likely with some spots maybe reach an inch. ETA remains iffy, but right now looks like it’ll arrive late Saturday night and rain heaviest during the wee hours of Sunday morning, ending around midday. This time frame is likely to shift, so check back for forecast changes.

Light Rain Thursday Night, (Low Confidence) Wintry Precip Friday Night

Rain Thursday Night

Sunny skies and pleasant during the day. Southerly winds could gust upwards of 25 mph.

That’s all ahead of an approaching front tonight.

HRRR Model shows a weak band of showers moving through Thursday Evening into the overnight hours.

ETA: 7PM-1AM

No severe or winter weather concerns. Just a light, chilly rain.

Mixed Precipitation Friday Night?

More “notable” weather will come Friday evening into Saturday with the potential for some snow by Saturday AM… Right now have a dusting for counties along the Plateau and a few counties east of I-24 along the TN/KY border.

NWS Discussion 01-14-2021

While current thinking is that the bulk, if not all, accumulation should stay mostly confined to the Plateau, there is not high confidence in a couple of factors that would change that forecast, namely how much moisture will make it down to us and how much dry air will eat the flakes on the way down. Much uncertainty with this one.

Stay connected as this forecast could change. Winter-time systems can sometimes overachieve (looking at you last Monday)

Unsettled Pattern Continues

Models hint at yet another mid week system that could bring more showers than we have seen as of late. There are still differences between GFS and Euro so there really aren’t any more details to be established at this time.

NWS Discussion 01-14-2021

More details on this potential system in upcoming blogs.

Have a great Thursday!

It’s Snowing!!! (In some places)

It has been a tale of two counties this morning

Parts of Williamson County have picked up an inch…

This isn’t even at elevation.

Even nearing 2 inches near Thompson Station..

Those in Davidson County haven’t been as lucky

Moisture that has infiltrated Williamson has been losing the battle with the dry air north of I-40 in Davidson County.

HRRR Model shows the dry air winning for a while before the moisture is finally able to move north.

HRRR Model 9AM-8PM Monday

Snow totals from NWS show southern Davidson County picking up 0.5″ with the northern part barely getting enough to measure.

While isolated spots could see around or just over an inch, we are still expecting most places to see less than an inch of snow.

NWS Nashville Discussion 01-11-2020

Snow will slowly taper off after noon as our high temp reaches 37°.

Tonight’s low will dip into the mid 20s. Any moisture on roadways will freeze. Beware of slick spots tonight especially on bridges and overpasses.

Next weather maker or lack there of looks to be Thursday night. But we’re not impressed.

The system really dries out before it gets here and while we’ll likely see clouds move back into the mid-state, I don’t expect much if anything in the way if precip, frozen or otherwise.

NWS Nashville Discussion 01-11-2020

Not much on the horizon, either. Scroll up to see this week’s warm up, though.

Sometimes, Snow Happens. Usually, Not So Much (here’s the cold rain y’all ordered). Watching Thursday & Monday.

Thursday morning the HRRR model thinks our rain system will be near the MS/LA/AR intersection with rain on its northeast side. Notice it has a snow band in West Tennessee. That’s not expected to impact us (but yeah, we’re watching it).

The system is coming at us. We will get rain Thursday, most likely in the afternoon. Exact timing is iffy. Euro model:

Rain will end sometime after midnight Thursday night, potentially with flakes mixed in. Total rainfall around 0.10″ with isolated amounts up to 0.25″.

Notice below a sharp line between very little rain (generally north of I-40) and potential-rainout rain (closer to I-840). Have low confidence the models have the line right. We could end up pretty dry, or kinda wet. All depends on the exact track of the low.

Frozen Precip Thursday Night?

Another classic “snowable air chasing the rain” situation.

Will it snow? Maybe.

Accumulate? Doubt it.

Several ingredients must merge at just the right time for snow: cold enough air for a long enough period of time aloft, surface temps cold enough to support freezing temps, and of course moisture timed up just right. Typically in these scenarios, the moisture heads out before temps can drop enough to support snow.

We might see a narrow window of opportunity for a few splat/melt snowflakes late Thursday night. Looks like temps may be briefly cold enough aloft, but too warm at the surface, causing flakes to splat/melt on the ground.

The Euro Model doesn’t give snow fans much hope.

Euro Precipitation valid Midnight Wednesday Night through 6AM Friday

The Euro sounding shows temps cold enough for snow after midnight Thursday night, but melting when flakes hit the ground. Ground temps will be relatively warm.

The GFS Model is even less generous with snow chances.

GFS Precipitation valid 6AM Thursday through 6AM Friday

NWS Nashville says the Plateau (the “they get more snow than we do” area) has a chance:

Temps again look to cool enough for a rain/snow mix in the evening, and precip looks to remain on the Plateau overnight. As of now, kept out any accumulation, but will not rule out some light accumulation on the Plateau.

NWS AFD 01-05-2021y

Could the forecast change? Absolutely and it probably will. Keep expectations low for now.

Keep The Faith Snow Fans: Monday

Another system is due in here around Monday. A few model runs have a wintry look.

Notice the Red “L” south of Florida Panhandle

The last two Euro models runs were interesting. In one, we had a low passing to our south with high pressure in the plains. That’s generally a good sign (but no guarantee) for snow. The latest run, not so much. Here’s a GIF:

We are entering the time of year when it might actually snow. Models aren’t good at pinpointing when or where, especially here. We aren’t far enough north to get reliable snow temps and we are not far enough south to reliably tap Gulf of Mexico moisture. Temps/Moisture are always playing tug of war. But sometimes, snow happens.

Stay connected with upcoming blogs as new info becomes available. Remember, old info is bad info.

The Great Flocking of 2020

Christmas Day 2019 we touched 70°.

Christmas Day 2020…

Yikes

Currently 20° with a wind chill of 7°. Remember to look after those furry friends, check in on the elderly/those without heat, and the pipes.

Roads were slick last night and remain that way this morning

Some areas did get flocked/dusted

Some improvement with the roads may occur, with the help from wind and sunshine. Although still expect some slick spots tonight as temps drop back down into the upper teens. (Melt then Re-freeze tonight)

Warmer Weekend

Saturday: approaching 50

Sunday: approaching 60

Both days will be dry. Next chance of rain looks to come Sunday Night/Monday Morning but we’re not impressed.

Euro Model predicts weak sauce showers.

Some areas may not see a drop

Looking Ahead

Monday and Tuesday will be dry with temps around 50°. Our next and more substantial rainmaker looks to come on Wednesday. This does have the potential to be a washout.

1-2″ likely