Today Is One of Those Days

Today is one of those days when, after commuting with the windows down, you peer out the office window and wish you were outside! Temps bottomed out at 58° in Nashville early this morning just before the sun came up. With low dewpoints, it was perfect.

Rest of Today

Lots of sun. NWS is expecting a high of 86° this afternoon, but with the dewpoint at only 56°, it’s going to feel about as nice as 86° can feel.

Yes, Pam, it is.

Tonight

Still cloud-free, we’ll drop down to around 63° overnight. Still very comfortable.

Friday Through the Weekend

No rain is expected through the weekend and even into next work week.

A decent high pressure system (blue “H”) is camping out above us, putting a lid on storm development. Looking at the 7 day qpf (rain) forecast map, it’s pretty obvious where the high pressure system is forecast to hang on.

If you’re looking at the map thinking “that looks like next to no rain for us and a lot for Florida.” You’d be right. We’ll have to see if slight rain chances creep into our area by the middle of next week, but for now, the forecast is dry.

So, What About Florida?

By now you’ve probably heard of Hurricane Dorian. Without getting into the weeds, just be aware that the current forecast from the National Hurricane Center has it reaching Category 4 strength and impacting the Florida east coast over the weekend. If you know folks down that way, make sure they have this info. This advisory as of 11:00 am AST. 

Back In Nashville… A Quick Word About Rainfall

Assuming we don’t get any more rainfall during August, we’ll end the month above normal at BNA.

For 2019, we’re still way above normal on precip at BNA. In fact, if we didn’t get another drop of precip between now and the end of the year, we’d still end up just above normal. Buuut, let’s not wish that on ourselves.

As always, we’ll be over on Twitter @NashSevereWx. Have a great day!


Storms Possible Today; Smaller Storm Chances Into the Weekend; Heating Up A Notch or Two

Yesterday was an eventful day weather-wise as storms bubbled up over I-65. They exceeded our expectations both in how many there were and how long they lasted. The expectation was that a few isolated cells would develop in the heat of the day, rain themselves out as the sun began to set, and leave us with a quiet night. Instead, we had numerous storms develop that were very electrically active and dropped some small hail.

Thursday

We could see some similar storms today, although not guaranteed. Some ingredients are in place (nerd speak: deep instability and strong lapse rates) for storms to get a little angry. Also, there are a lot of outflow boundaries laying around from last night’s storms that could enhance lift in areas where they lurk. Outflow boundaries are the winds at ground level that ripple out of dying storms as they collapse. They can be the focus of additional storms.

The HRRR model thinks it will look something like this. Loop is from 1:00 pm – 9:00 pm.

If you have outdoor plans this afternoon and evening, watch for dark clouds. Be suspicious of them. We’ll be watching radar.

The Storm Prediction Center believes there’s a 5% chance these storms will have winds of 58+ mph within 25 miles of you. Lightning is the big thing to watch out for. Yesterday, a lightning strike hit right in the center of Smith Park in Brentwood from a distant storm. Those on the trails probably won’t soon forget what that was like.

High temps should get to about 90° today.

Tonight

Tonight, storms should start to wind down by 10:00 pm. We’ll drop to a sticky 69°, especially sticky for those who receive rain today.

Friday

The energy that is helping today’s thunderstorm development will push back to the west as we get into the weekend. The expectation is that the rain/storm chances will go down beginning Friday….but won’t be zero. We’re left with a 20% of storms Friday and a high of 91°. Heat indices will start to climb into the mid-90s, however, as the dew point creeps upward.

Small storm chances will remain with us each day through the weekend and into next week. We expect storm chances to increase by the middle of next week as energy pushes in, but we’ll see how that pans out as we get closer. Take frequent breaks and drink lots of water! It’s going to be hot!

 

Summer Pattern Continues With Pop-Up Storms; Some Cool Rainfall Stats

Wednesday

Notice the H’s near us on the map. High pressure is in control today. This typically puts a lid on the atmosphere’s willingness to storm. While it’s possible the western half of the state could see a brief storm, the odds are against any one place receiving rain. Temperatures will be slightly above average with a forecast high of 91°. There won’t be much of a breeze to provide relief, so take frequent water breaks!

Tonight

*If* anything bubbles up on radar over us, which is unlikely, it will quickly fall apart leaving us with a muggy evening and temps settling down to around 70° by daybreak Thursday.

Thursday

Rain/storm chances go up slightly on Thursday as the ridge of high pressure slips off to our E ever so slightly. Rain chances will be around 20%, so not everyone will see these typical summer-time pop up storms. Temps go up, too. 93° is the forecast high. HRRR illustrates the possible storms. Loop from 1:00 pm – 7:00 pm.

Friday Through The Weekend

Afternoon and evening storm chances remain in the forecast through the weekend. It will be toasty with highs in the low to mid-90s. If you’re lucky enough to get a thundershower to cool you down, the sun will then come back out and steam the neighborhood up. Summer is definitely here in Mid-TN!

The Tale of Two Months

May was D.R.Y. It’s usually our wettest month of the year. It turned out to be our driest month year-to-date by far. The graph below tells the story pretty well. We received about 29% of our normal rainfall.

We’ve snapped out of our dry episode for June, it seems. We’re currently 3+ inches above normal for the month.

For 2019, we’re still in a big surplus due to the huge rains we had early in the year. Remember when we had over 13 inches of rain in February alone? For the year, we’re about 11 inches above normal.

Nice Weather For A Couple of Days, Unsettled Pattern Sets Up On Sunday

Today

Last week, I spent several days at various places on the Pacific coast. The weather was fantastic. Today in Nashville is awfully close to what you find out west this time of year. If you took the day off, are at camp this week, or even mowing the grass, good move. This is about as good as it gets in mid-June.

Expect an afternoon high of 77°, but the dew point is only 48° (as of noon). Put out the hammock and enjoy…safely.

Tonight, we should dip down to 53°. The record low we’d be aiming for is 48° back in 1968. Not record breaking tonight, but certainly nice.

Friday

Our temps start to go up, but the sun stays put. We should hit 81°. Dew points should stay in the upper 40s again. Another nice day!

If you have outdoor plans Friday evening, go for it. Lows will dip down to around 63°. No rain.

Saturday

We crank the heat up a little higher on Saturday, up to 88°. Moisture will be on the increase also, not in the form of rain, but in the form of humidity. Dew points jump into the low 60s, which will be noticeable. We think rain will stay away for Saturday as the next system approaches. The 3km NAM model thinks the rain situation will look like this (7am – 7pm Saturday).

Sunday through…..

On Sunday, a front will approach from the north and will stall out. It’s hard to get fronts to really push through our part of the country this time of year. What we’re left with is a decent amount of moisture, decent instability (especially during the afternoon) and daily rain/storm chances. Because this system stalls, rain/storm chances will likely hang around for quite some time. Severe weather doesn’t look to be a concern right now. If you’re down at Roo, follow all instructions if lightning becomes a thing. If there’s any day when it could, Sunday is it.

 

Severe Threat Has Ended; Lots of Sun for the Weekend

Today’s Severe Threat Is Over

As we’ve been saying for several days, severe storms require certain ingredients. Most of them were in place, but we were lacking enough cold air aloft to get good updrafts going.

So it goes.

Remainder of the Afternoon

The sun is making a return as the rain moves E. We expect the sun to be mixed with some clouds for the rest of the afternoon and evening.

Satellite picture as of 3:11 pm.

Cool air is returning as a cold front pushes through tonight, dropping our low to 47° tonight.

Friday

We’ll see a mix of sun and clouds on Friday with a high of 52°, but rain will be long gone. Friday night, lows will dip down to 32°, but no precip.

Saturday and the Rest of the Weekend

There’s really not much to write about for a change! Plenty of sunshine, no precip, and a chance to dry out! Temps will be seasonable with a high of 54° Saturday and 58° Sunday. Lows will be in the low to mid 30s.

The next chance of rain doesn’t look to be until at least the middle of next week.


Tornado Watch, Wind Advisory In Effect Until 7:00 pm

Tornado Watch in Effect Until 7:00 pm

Severe Weather Possibilities Today

We are expecting showers and thunderstorms today as a strong storm system moves through the Upper Plains and Great Lakes region. The system will drag a cold front across our area today bringing storms, some of which could be severe.

The Storm Prediction Center upgraded us overnight to an “Enhanced” risk of severe weather, which is a 3 out of 5 on the risk scale. This translates to these probabilities of seeing “x” within 25 miles of you today.

  • Tornado: 10%
  • 1″+ diameter hail: 15%
  • 58 mph + damaging straight line winds: 30%

This is worth watching. But, also consider:

  • No tornado within 25 miles of you: 90%
  • No large hail: 85%
  • No damaging winds: 70%

Timing: 2-7 pm

After the line of storms moves through, the severe threat will end.

What To Do

Stay connected today. Don’t let this sneak up on you by being unplugged. Have a way to get warnings for *your location.* Do you know where you are on the map? If not, open Google Maps or similar GPS-based software and find out where you are located in case warnings are issued.

Do you know the difference between a “watch” and a “warning?” Find out answers to this and many other questions you may have about how to prepare for days like today here: What To Do

 

Warnings will not be posted here. We will be live on Periscope (link will be provided in the Twitter feed). We will also live tweet throughout the day @NashSevereWx. Don’t have Twitter? Follow us here.

Wind Advisory

The other story today is the non-thunderstorm winds. A wind advisory is in effect through 7:00 pm tonight. Winds, outside and separate from thunderstorms, could gust as high as 45 mph.


Windy, Severe Weather Possible Today; Cooler Air Returning This Weekend

Possible Severe Weather Today

Today will be another warm day with morning lows around 61°, but highs warming to around 73°. Southerly winds could gust even higher than today as a strong system approaches from the west. As far as storms go, let’s start general and work toward specifics.

SPC Severe Risk: 3 out of 5

SPC’s risk translates to a 15% chance of seeing severe weather within 25 miles of you. To break it down further, here are the chances for each severe weather type, again, occurring within 25 miles of you.

  • Tornado: 10%,
  • 1″+ diameter hail: 15%,
  • 58 mph+ straight line winds: 30%.

Or to say that another way,

  • No Tornado: 90%,
  • No 1″+ diameter hail: 85%,
  • No 58 mph+ straight line winds: 70%.

Timing

The HRRR model below illustrates two potential rounds of storms, with varying severe potential.

The first round arrived at the Tennessee River after midnight, but fizzled as it approached Nashville during the wee hours. If the HRRR solution is “mostly right” (no model is exactly right), round one won’t be a problem for us. If the line keeps trucking east, it could be a bumpy night. We don’t think this will happen, but we’ll watch it closely.

Round two arrives around 4 pm, give or take a few hours. This line does look to push all the way through our area and is the main severe weather concern for Today and the reason the above severe probabilities were issued by the Storm Prediction Center. HRRR model is below and runs through 5:00 pm this evening.

NAM3 model agrees with a 4 PM ETA, plus or minus a few hours.

The line doesn’t look all that robust on these models though. Begging the question:

Are the Ingredients There For Severe Weather?

Instability (CAPE): Yes, but mostly for Round 2. HRRR and NAM3 models both think sufficient CAPE will be present for the late afternoon/early evening round. The first round this morning, not so much. HRRR illustrates the CAPE arriving in time for the late afternoon/early evening round.

Shear: Our NWS had this to say about shear. Spoiler alert: yes.

With such a strong upper low, 0-6km shear will be 50 to 70 knots, and 0-1km shear will be up to 40 knots.

Moisture: Dew points should reach 60° and maybe a little higher if models have their way. So, moisture appears present.

Limiting Factor

There are caveats to Thursday’s setup. Basically, the strongest dynamics will be north of us, closer to the parent low. Also notice how models depict a broken, kinda weak looking line coming through in round 2.

Heavy Rainfall

This is not the setup where we expect to receive multiple inches of rainfall. However, if you get underneath a storm, it could drop a quite a bit of water in a few minutes as the storm races through. The WPC says there’s only a 5-10% chance of seeing flash flooding within 25 miles of you on Thursday.

Forecast rainfall totals dropped dramatically since two days ago. Under 1″ appears in the NWS-Nashville forecast grids.

When Is It Gone?

The late afternoon/early evening line of storms will signal the end of the severe threat. Temps will drop to 45° overnight into Friday as the cold front pushes through.

Friday Into the Weekend

The sun returns Friday, but highs will reach the mid 50°s; say goodbye to the 70°s we’re enjoying now. Lows will be right around freezing. Interestingly, there are hints of a quick system bringing in a few flakes Sunday night. But, models are off in a corner arguing about that. Each has its own opinion. I overheard the Euro yelling “NO” at the GFS and Canadian models who brought up the whole thing in the first place. We’ll check back with them later and see how that’s going. Usually the Euro has more credibility but like most people arguing in a corner no one is completely right.


Showers Continue Today; Severe Storm Possibilities Saturday; Nice Sunday

Story #1: Strong/Severe Storm Potential Saturday

The Storm Prediction Center has assigned a “2 out of 5” risk category for most of us on Saturday. Areas W of 65 has been in an Enhanced or “3 out of 5” risk category.

 

Reasons We Might Have Severe Weather

As a low pressure system progresses through the Plains and upper Midwest, it will drag a cold front through Middle Tennessee tomorrow. With this system will come some storm ingredients.

Highs Saturday will be noticeably warmer than today. We’re forecast to top out at 67°. So, that’ll be nice.

For severe weather around here, we need a few ingredients. Namely, instability (CAPE), wind shear, lift, moisture. We will have plenty of moisture and plenty of lift (from the cold front).

Let’s focus on wind shear and instability.

The wind shear is crazy high. Like, really high. For severe weather, in the right environment, numbers in the neighborhood of 250 are sufficient to create rotating, strong/severe thunderstorms (note not all rotating storms make tornadoes, but they can make tornadoes). The HRRR model thinks tomorrow we’ll see shear numbers of 600, 700, or even 800. These numbers are obviously sufficient for severe weather, and maybe even too high.

Instability – measured by CAPE – is a different story. The same HRRR model run shows sufficient CAPE to make storms west of us, but it falls off significantly as the system approaches I-65….but the CAPE is not zero. Model animation runs from 10:00 am to 6:00 pm Saturday.

CAPE/instability will be high enough that we’ll have our eyes peeled to the west for sure. And if that CAPE hangs on a little longer, it’ll team up with other ingredients and create very strong/severe storms.

Reason Severe Weather Might Be Limited

  • Main reason: CAPE (Instability, Storm Food) drops off, and the storms weaken as they approach. This may or may not happen.

Possible Hazards

All hazards are possible with this event. Damaging straight-line winds will be the primary threat, but hail and isolated tornadoes are also possible. Keep in mind, though, the probability of severe weather of some kind occurring within 25 miles of you is 15%. Wind, hail, tornado probabilities will be broken down individually in tomorrow’s update.

Localized flooding is also possible, but the probability of that is “marginal,” around 5% to 10%.

Timing

Afternoon and early evening. More detailed timing will be evident Saturday morning. Range of possibilities is too great to narrow it down.

Sunday

The sun will return! High temps will be near 63° with light winds.

Glad You asked.

Story #2: 7-Day Rainfall Totals

It’s no secret that we’ve had too much rain this year. Unfortunately, current forecasts show more on mid/late next week. There are a lot of ways this could change, mostly dealing with the specific areas affected the most, but the Weather Prediction Center paints 4-5 inches across our two counties from today through Friday morning (March 15) at 6:00 am. So, yeah. We’ll have more to say about this as a mid-late week system approaches and make adjustments from there. After rain today and Saturday, ETA for the next round of heavy rain is late Wednesday into Thursday. Stay tuned.


Enjoy the Sunshine Today. Rain Returns Overnight. Second Half of Weekend Salvageable.

This pic is from The Gulch Cam as it basks in the sunshine and 60° temps as of 1:00 pm. 61° is our forecast high for today, so we’ll see if we nudge a degree or two above that. I’m sure we won’t mind if we do. If you like sunshine, enjoy today. Here’s why:

Rain Returns Tonight

As of 1:00 pm, rain is building over Arkansas and Louisiana, which will move our way tonight. All of this is due to a low pressure system generally located over Texas. This low will push east along the Gulf Coast states.

When Will the Rain Start?

The 11:00 am run of the HRRR model isn’t all that excited about solid heavy rain overnight. It keeps rain out of our area til the wee hours of tomorrow morning. So, evening plans tonight look to be in good shape.

If you are outside tonight, though, the wind may still be a little gusty, so a jacket will be a good idea. Tonight’s low should get to 49°.

Friday

Rain will be possible all day Friday with outdoor plans being a nope. Thunderstorms will also be possible, but not likely.

The Euro’s take on “storm food” shows that there will be some potential convective energy out there, but it will be really slim. Not nearly impressive enough for strong storms. Perhaps a few lightning strikes.

Friday, we’ll reach a high of 56°. Friday night, we’ll dip down to 46°.

Saturday

As our low pressure system pushes off to the east, rain will continue, but start to wind down from SW to NE. It’s not possible to tell you exactly when the final shower will move through as some wraparound moisture on the back side of the low will keep light rain chances around through the evening. Our high should reach 55°, and we’ll drop to 40° overnight into Sunday.

Beyond…

Hazards Between Now and Saturday Night?

Winter weather? Nope. The cold air will stay to our N.

Severe weather? Nope. The low will pass S of us, which provides a much more stable environment than if it were to pass N of us.

Flooding? Nope. We’re not expecting enough rain to cause problems.

Soggy luminaries? If your neighborhood is putting the fun candles & white bags in the street this Saturday, as mine is, they could get soggy, unless the rain pulls out early. Curbs could still be wet, though. Have a rain date ready.

 


Sunny and Warmer Today; Rain Returns for Second Half of the Week

David, Will and I (this is Andrew) are good for each other. We’re the kind of friends that sit around and text each other at night about weather data. At 7:39 pm, David said “Feels like it’s gonna fog.” We continued by exchanging weather data numbers that would appear, to some, to be some kind of lock combination. It was a blast.

Sure enough, on I-24, on my way home from a Christmas party we noticed Mill Creek starting to get a bit foggy at the bridge. We all knew what this meant. With temps expected to be in the low 20s, freezing fog was on its way. This occurs when fog clings to surfaces that are below freezing, including elevated road surfaces, and becomes an issue for drivers.

NWS also saw it and issued a freezing fog advisory, which expired at 9:00 am this morning.

But, it was cold. NWS pointed out that Brentwood dropped to 15° and BNA (the airport) dropped to 20°. Let’s just forget that happened and move on.

For the Rest of Today…

Now that the sun is out temps will rapidly climb to near 50° with plenty of sun. Seems like it’s been a while since we’ve had to count that high!

Tonight

If you follow weather somewhat closely, you probably know warm-ups generally occur before a precip-making system moves in. This would be correct. Clouds move in tonight ahead of our next weather maker, but we’ll stay dry, and temps should bottom out at or around 32°.

Wednesday

Our warm-up continues on Wednesday with a forecast high of 54°. There will probably be more clouds than sun, and those clouds could even squeeze out a sprinkle of rain, but promise me you won’t cancel any plans over that chance. Y’all….54°.

Wednesday Night Through Weekend Weather Maker

A low pressure system will be developing in Texas and Oklahoma around the middle of the week that will spread rain and maybe a few thunderstorms over the southeast during this period. The track of this low pressure center will be S of us, which will keep low severe weather chances across the Gulf Coast states and leave us out.

Timing

Best guess from our local NWS office:

…light rain expected to spread eastward into our western counties after midnight into the day on Thursday. As the upper low inches eastward and deeper moisture enters the forecast area, more widespread rain is anticipated by Thursday night and Friday. Cannot even rule out a thunderstorm or two during this period… The upper low is forecast by the 00Z ECMWF and GFS [two models] to pass just south of the Mid State from Friday night into Saturday, with off and on light rain continuing throughout the CWA [our area] before finally ending Saturday night.

Rain Amounts

Through 6:00 am Sunday morning, WPC projects we’ll see between an inch to an inch and a quarter of rainfall.

Any Hazards?

Severe Weather: No. As mentioned above, the low will pass S of us. Good news.

Winter Weather: No. Cold air will stay trapped up north.

Flooding: No. An inch of rain spread out over that long of a period won’t be a problem.