Rain Winding Down; Flash Flood Watch Until 1 PM

Note: because seconds count in disseminating warning information, no warnings are ever posted to this website. Follow @NashSevereWx on Twitter and other reliable sources of weather information for warning information.

A Flash Flood Watch is in effect until 1 PM Sunday:

Rain still hasn’t worked its way out of our area. The Flash Flood Watch remains until 1 PM. As you can see from the below water vapor image, the dry (dark colors) air is creeping closer to the Mississippi River.

The dry air won’t arrive until some time tonight. So while we don’t think we will see as much rain today as we saw last night, you can expect more off and on showers and a few thunderstorms.

Current Radars:

Current Official Temp (taken at :53 every hour)

Extended Forecast

Weekend Rain Details

Water vapor imagery (dark means dry, white means wet) depicts the rainmaker messing up our weekend:

This morning, light rain was working itself into Middle TN from the SW. The heaviest rain will pass to our West, but we should still see a few light showers before noon. Morning activities shouldn’t be ruined. As of 9 AM, I didn’t see any lightning in the approaching morning showers.

Rain chances increase this afternoon. It won’t be raining the entire time. Expect off and on rain.

Here’s what the short range weather models say.

1.  HRRR (High Resolution Rapid Refresh) has the main batch of rain arriving around 2 PM:

2.  RAP (Rapid Refresh — has lower resolution) agrees with the HRRR, sending in steadier rain around 3 PM:

We could see thunderstorms, with lightning and heavy winds, mixed in with the rain. The Storm Prediction Center thinks there is a 5% probability of a 58+ mph wind gust happening within 25 miles of us:

But, this will mostly be a rain event.

Those checking Twitter around 1 AM this morning may have seen our tweet about our inclusion (by the Storm Prediction Center) in a 2% tornado area. We have since been removed from it; that 2% tornado area now only exists in LA and Southwest MS.

A soaking rain is expected sometime tonight, extending into the overnight hours.

Rainfall totals forecast through 7 AM Sunday morning are 0.69″ in Davidson Co. and 0.71″ in Williamson Co.

Saturday’s high temps will settle into the mid/upper 80s, courtesy of the rain and corresponding cloud cover.

Sunday, expect to wake up to rain, but rain chances will slowly decrease through the afternoon and into the evening. Just under another half-inch of rain is expected, with most of that falling in the morning.

Conditions should improve Sunday night, and Monday actually looks decent. However, without the rain to cool us off, look for a high of 92, with very high humidity.

Current Radars:

Current Official Temp (taken at :53 every hour)

Because I Feel Like It

Extended Forecast

Rainy Labor Day Weekend

Current Official Hourly Observation (taken at :53 on the hour)

Today A Day of Dry Air – High 95

No rain today. Just heat. The NAM’s Dew Point Map shows the area of drier air over us at 1 PM.

18z 2m dew point

No rain expected for H.S. football tonight.

Current Radar

Labor Day Weekend – WET! – Wake Up Low 70s, Highs Upper 80s

This infrared image from 9:45 AM Friday shows the approaching Labor Day Weekend Weathermaker.

ifrared

A low pressure system in the Great Plains will arrive, picking up the energy from the giant blob (disturbance) in the Gulf of Mexico. These two disturbances . . .

. . . will combine to activate a rain out of part of our Labor Day Weekend:

This morning, it appeared the rain was likely to begin Saturday morning. This afternoon, weather model runs suggest it won’t start until after noon. Now, tonight, short-range models predict rain will start mid-to-late morning. As always, use weather models for guidance, not gospel.

The heaviest rain, with a few thunderstorms, will likely begin in the late afternoon and early evening. The NAM thinks the worst of it will arrive in Williamson and Davidson County at 7 PM. The other weather models agree.

0z radar

These showers and storms will continue overnight into Sunday morning.

As we approach noon on Sunday, the showers will begin to taper off. Scattered (hit and miss) showers will become prevalent in the afternoon into the early evening, before settled weather arrives and the rain shuts off on Monday.

The Storm Prediction Center is not forecasting severe weather for us. Just rain with a few garden variety thunderstorms.

From Friday morning to Monday morning the Weather Prediction Center believes between 1″ and 1.5″ of rain will fall.

qpf 1-3

I am forecasting closer to 2″.

Extended:

7-Day Forecast for Latitude 36.17°N and Longitude 86.78°W (Elev. 479 ft) - Windows Internet Explorer 2014-08-29 13.08.44

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Rain Chances Tonight & The Weekend

Current Official Hourly Observation (taken at :53 on the hour)

Today – Humid, Chance of Rain Later – High 93

Heat indices will be in the upper 90’s.

There’s a small chance a shower will pop up later this afternoon or early tonight. At 5 PM tonight, the HRRR has a few showers wandering around N of I-40. It’s possible one will stray over us, but it shouldn’t be enough to wash us out (NOTE: we’ve been very wrong about that before):

COD Meteorology -- Numerical Model Data - Windows Internet Explorer 2014-08-28 10.02.15

Any showers should dissipate after dark. Just keep an eye on it at Live On The Green, Vandy, and Titans tonight.

FridayDry Air – Wake Up 71, High 95

A dry air mass will make its way into Middle Tennessee Friday morning, and hang around for the rest of the day.

Dew Point 12z

Combine the dry air with high pressure, and we get temps in the mid 90’s.

Saturday – Humidity & Rain Returns – Wake Up 70, High 89

The dry air mass be replaced by southerly winds funneling in moisture into Nashville.

Then, a trough of low pressure will move in from the west, break down the dome of high pressure, and usher in a series of disturbances producing showers and thunderstorms this weekend.

The Storm Prediction Center is not forecasting any severe weather for us, but the rain will be hanging around, potentially messing up weddings and football games.

Three Day Weekend Rain ETAs

No one knows exactly when it will rain. But, here’s what two weather models say:

GFS (American): scattered rain showers are possible Saturday; more likely Saturday night than during the day. Rain is likely Sunday morning, then clears up in the afternoon. Kickoff in Knoxville Sunday night (Utah State vs. Tennessee) will be dry. Then, more rain arrives Monday.

European: most of the day will be dry Saturday, but rain/storms arrive around 7 PM Saturday. During the wee hours of Sunday morning, there will be a break, but around noon Sunday, the skies open up, and it rains the rest of the day (here and in Knoxville for Utah State vs. Tennessee). Rain winds down Monday morning, then clears up, salvaging the end of the three day weekend.

Inconsistencies in these two models mean low confidence in any timing. That’s why your crapapps and other forecasts are hedging their bets with 50% chances of rain (if your app has anything more than 70% at any given time, delete it).

Since a few of you will ask, my “gut” says it’ll rain late Saturday night, then off and on Sunday. I think there willi be rain at the UT game Sunday night.

Extended:

7-Day Forecast for Latitude 36.17°N and Longitude 86.78°W (Elev. 479 ft) - Windows Internet Explorer 2014-08-28 10.04.03

Rainfall totals Thursday morning through Sunday morning: .25″ to .75″.

qpf 1-3

This website supplements @NashSevereWx on Twitter.

Weekend Rain

Current Official Hourly Observation (taken at :53 on the hour)

TodayUnder the Dome – High 92

A dome of high pressure will help lift our high temps a few degrees above normal. This surface temp, pressure, and wind map produced by the GFS from 1 PM shows the dome of high pressure and a northeast wind (blue arrows).

2m temp

An afternoon shower cannot be ruled out..

ThursdayMore Humidity; Afternoon Rain Possible – Wake Up 72, High 94

High pressure remains. Throughout the day, the NE winds will turn, and become more southerly. This will push the dry air mass north and allow moisture (humidity) to begin to trickle back into Middle Tennessee by the late afternoon.

At least the added little bit moisture will give a slight chance for showers and thunderstorms during the afternoon.

Friday – Humidity Still Rising – Wake Up 72, High 92

More of the same: southern winds pushing in higher humidity (but still tolerable), with an afternoon rain chance.

The GFS weather model predicts rising dew points (moisture) around 7 AM Saturday morning.

Dew Point 12z

Combine this moisture with a disturbance poised to move through Saturday/Sunday, and it’s looking to be a soggy weekend. Rain is more likely Sunday than Saturday. Humidity levels Sunday will be oppressively high.

Extended:

7-Day Forecast for Latitude 36.17°N and Longitude 86.78°W (Elev. 479 ft) - Windows Internet Explorer 2014-08-27 12.19.04

Rainfall totals Wednesday morning through Monday morning: 1.00″ to 1.75″.

qpf 5 day

And, finally, for no reason, this:

This website supplements @NashSevereWx on Twitter.

Dear Bmack,

Dear @NashSevereWx,

Twitter _ Notifications - Windows Internet Explorer 2014-08-26 12.03.14

Dear Bmack,

1.  This should only be a concern if the weather determines whether either of you will say “I do.” I’m betting that’s not a concern, so even if it rains, you will still accomplish the mission of the wedding.

2.  You’re getting married on the First Weekend of College Football Season. This is always a risky proposition.

3.  For a defense of wedding day rain as “irony,” click here.

4.  An “upper level shortwave” is forecast to arrive this weekend, and give us a chance of rain. But, it’s too soon to recommend anyone worry about a specific “will it or won’t it” block of time this weekend. Just for fun, I consulted two medium-range weather models. One said “rain” (Euro), the other said “it’s close, but probably dry during that time” (GFS). Please draw no conclusions from this. These models have been waffling from run to run. Again: Draw. No. Conclusions.

5.  I’m betting on heavy rain and maybe a few thunderstorms very late Saturday night. IMO, that’s perfect.

fireworks animated GIF

6.  Congratulations.

Current Official Hourly Observation (taken at :53 on the hour)

TodayMaybe a Passing Shower – High 91°

Wednesday & ThursdayNo Rain Expected – Highs 93° and 94°

Friday – Sunday: Rain Chances Return

The aforementioned upper level shortwave is expected to kick up a bunch of rain and thunderstorms, off and on, all weekend. The Euro weather model is pretty aggressive, predicting heavy rain, mostly late Saturday into Sunday morning. The GFS scatteres it out a bunch more. It’s really too far away to say anything more specific than that. This will probably change as we near the weekend.

7-Day Forecast for Latitude 36.17°N and Longitude 86.78°W (Elev. 479 ft) - Windows Internet Explorer 2014-08-26 12.29.02

Rainfall totals Friday morning through Sunday morning appear modest: 0.25″ to 0.50″.

http___www.hpc.ncep.noaa.gov_qpf_95ep48iwbg_fill.gif_1409074300 - Windows Internet Explorer 2014-08-26 12.31.59

This website supplements @NashSevereWx on Twitter.

Regular Miserable August Humidity is Back!

Current Official Hourly Observation (taken at :53 on the hour)

High pressure will keep our temps today, and the rest of the work week, in the low to mid 90’s.

Humidity will remain uncomfortable, but not unbearable.

Dew points which were in the 70s this weekend (irregularly unbearable) will be in the 60s this week (regularly unbearable), keeping the heat index under 100.

Monday – Partly Sunny High 91

There’s a slight chance of showers and thunderstorms this afternoon.

The HRRR paints the best picture by showing hit or miss (mostly miss) showers firing up around 2 PM.

19z HRRR

The models are in relative agreement that the bulk of the activity will stay east of I-65 and south of I-40. Shower and thunderstorm activity should cut off during the overnight hours.

Tuesday & Wednesday – Mostly Sunny & Hot

The high pressure will continue keep us dry and hot. High temps will be in the lower 90’s and lows will be in the lower 70’s. Humidity will once again be uncomfortable but bearable.

Be sure to stay hydrated…Just not at the expense of children.

Extended:

SEC Week 1: Rainy?

There is no certainty on this, but the medium range weather models (GFS, Euro) suggest rain is possible Saturday at Auburn, Gainesville, and Starkville.

Heat Index 100° to 105°; Chance of Rain

Current Official Hourly Observation (taken at :53 on the hour)

Rain totals:

Davidson County

Williamson County

There were a number of places that received over and inch of rain from the showers and thunderstorms yesterday. This added soil moisture will make us more humid and cause the heat indices to go up.

Sunday – Heat Advisory – High 95

heat advisory

The National Weather service has placed us under a a heat advisory until 9 PM because of high temps in the mid 90’s and high humidity. This moisture will cause the heat indices to be between 100 and 105!

Conditions will be favorable to produce a chance for thunderstorms once again this afternoon. The NWS is forecasting these showers and thunderstorms not to be as widespread as yesterday. In addition, they believe that our best chance for rain will be this afternoon into the evening.

Monday – Hot and Humid – Wake Up 73, High 92

We will be a few degrees cooler than the previous couple of days but still of the above the normal temps for this time of year. In addition, high humidity will continue to push the heat index near 100!

We will have a chance for another round of afternoon showers and thunderstorm but overnight those chances diminish completely.

Tuesday– Hot & Rain Free- Wake Up 72, High 92

Conditions will remain unfavorable for thunderstorm development on Tuesday along with the rest of the work week. We will remain hot and humid!

Stay cool and hydrated y’all!

Extended:

extended

Wicked Hot, Rain/Storms Today? (Maybe)

Current Official Hourly Observation (taken at :53 on the hour)

Any showers will weaken and taper off overnight.

Sunday – Hot & Humid – Low 75, High 96

Heat indices will be between 102 and 106.

We will have another chance for an afternoon thunderstorm to cool us off.

Here is what a thunderstorm looks like from space!

Monday – More Pain – Wake Up 72, High 92

Hot and humid, with heat indices in the triple digits.

Afternoon showers are possible.

Extended:

In the Shade / Outside the Shade

Current Official Hourly Observation (taken at :53 on the hour)

Saturday

In the Shade: 95°, Heat Index 100°

Outside the Shade:

dragon animated GIF

Sunday

In the Shade: 96°, Heat Index 102°

Outside the Shade:

20 GIFs That Perfectly Express How Hot It Is Outside

Outside the shade, the heat index (“feels like” temp) will soar into the 100° to 105° range both days.

Heat-of-the-Day thunderstorms remain possible Saturday & Sunday.

Disneynature Headlikeanorange animated GIF

Some storms could even be strong.

Extended Forecast

7-Day Forecast for Latitude 36.17°N and Longitude 86.78°W (Elev. 479 ft) - Windows Internet Explorer 2014-08-22 16.50.07

Emotional Britney

This website supplements @NashSevereWx on Twitter.