Not Again! Rain Threatening Our Weekend

After a dry and warm week, rain threatens to return this weekend.

A chance of rain is in Thursday’s forecast, but the better chances are Friday and Saturday. Looks like a very slow rain system.

The Hi-Res NAM delivers showers Friday. Here it is Friday night at 7pm:

The American-GFS Model agrees. At 7am Saturday, rain is still falling (this model keeps it raining most of the day).

The European model agrees with a slow moving light to moderate rain event Friday and Saturday. Here it is Saturday at 1pm:

The slow movement threatens to deposit 1″ to 2″ of rain over a 48 hour period.

The possibility of locally heavy downpours may prompt flooding concerns.  The NWS is watching this very carefully.

A few thunderstorms are possible; however, this should primarily be a rain event.

River Levels (going down), End-of-Week Rain Chances

Just finished the NWS week-ahead briefing. Here’s what’s up:

Flooding Concerns

Rainfall totals over the weekend:

No river or creek in Davidson or Williamson County is expected to rise further. Here are three (actually, four) examples to put your mind at ease.

1.  The Cumberland River rose quickly this weekend, but will not approach flood stage. It’ll level off today, then fall quickly Tuesday and Wednesday:

2.  Harpeth River

(a)  at Franklin:

(b)  at Bellevue:

3.  Mill Creek at Antioch (site of flooding this weekend) also way down from flood stage:

This Week’s Weather

Dry and increasingly warm weather is expected today through Wednesday.

Rain chances increase a bit Wednesday, then increase Thursday and Friday.

The Thursday-Friday rainmaker is a screwy system the models are not handling well:

If these amounts verify, we would not have flood concerns. NWS is closely watching these rainmakers given the recent rains.

Showers linger into the weekend, however, “there is a lot of uncertainty” with this system. Weekend temps will be a little bit cooler with scattered showers.

Next week

Our average weekly rainfall for the first week of May is around 1.5″. The forecast is for slightly above average precipitation.

Dry Weather Ahead

No rain expected through Wednesday night:

Temps will top out in the upper 70s or low 80s Monday through Wednesday. A small chance of rain arrives Wednesday through Saturday. No severe weather in the forecast.

In case you missed it earlier, here are the 24 hour rain totals from Saturday:

 

The Rain May Be Gone, But Flood Danger Remains

Several Flood Advisories and Warnings remain in effect this morning. Water can still rise and remain dangerous even after the rain has stopped. Water packs tremendous power, respect it. Don’t drive through it. Flooding reports continue to pour in to the NWS.

Rainfall totals from 7am Saturday to 7am Sunday:

 

It appears today’s rain is over. The HRRR delivers maybe a passing drizzler. All measurable rain is long gone.

The RAP agrees. Can’t rule out a passing, very light, shower. But, things look pretty clear.

Get outside. Maybe hit up Franklin’s Main Street Festival.  Temps in the upper 60s, low 70s.

Rain & Storms To Continue Sunday

Rain is likely overnight tonight as we sleep. So says the Hi-Res NAM (4 AM):

Several other models say the same thing — rain piles in during the middle of the night, and slowly moves across the area in the morning through noon. It finally departs sometime tomorrow afternoon/early evening.

Sure hope that’s wrong and does not verify — we’ve already had enough rain. Localized flooding is possible if the rain persists; however, this would be nothing like the May 2010 flood.

We may see a few thunderstorms. Some may be strong, but we aren’t expecting severe weather.

Sunny skies return Monday and Tuesday.

Severe Thunderstorms (Tornado, Hail, Wind) Possible Later Today

The steady rain is moving out. Nevertheless, the Storm Prediction Center has introduced a Slight Risk of severe weather for us this afternoon and tonight.

The probability of a tornado within 25 miles of you is 2%:

The probability of 1″+ hail within 25 miles of you is between 5% and 15%:

The probability of damaging winds (58mph+) within 25 miles of you is also between 5% and 15%:

The Hi-Res NAM shows a particularly nasty grouping of storms around 7pm:

The morning HRRR run shows the arrival of off and on showers and thunderstorms this afternoon and tonight:

Do not make specific plans based on this model data. This is not guaranteeing dry weather exactly at 6 pm. The point is that you can expect a switch from a more constant rain to an off-on rain sometime tonight.

NOAA forecasts almost 2″ of rain through Sunday morning at 7 a.m.

Follow along on Twitter (@NashSevereWx) for more details with during-storm activity.

Before You Go To Bed: Country Music Marathon Update

Plan for rain.

The NWS forecasts rain at 7 a.m. Four weather models agree:

HRRR:

RAP:

Hi-Res NAM:

SREF: holds the heaviest rain until mid-morning.

Over 1/2″ is expected to fall from 7am to 1pm Saturday:

We also can’t rule out a thunderstorm to two, but I think it’ll be just rain tomorrow morning. Lightning should not interrupt the race (but no promises).

Morning sports are very likely to rain out.

 

Everything You Wanted to Know About Saturday’s Wet Weather

Because this is the eve of the Country Music Marathon, Franklin’s Main Street Festival, countless baseball, soccer, [insert preferred outdoor sport] games, let’s go way overboard with the weather models. We’ll ask the weather models about Tonight, Sat 7 a.m., Sat 1p.m., and Sat 7 p.m. Sunday’s forecast is mentioned at the end.

Summary: All the models rainout Saturday morning. Outdoor ball games are very unlikely. The Hi-Res NAM heroically attempts to dry out our Saturday afternoon & night. We expect around 1.00″ of rain beginning tonight through Saturday night. Look for more rain Sunday, but not nearly as much as we’ll get tomorrow. Thunderstorms are also possible both days, mostly in the afternoon.

Tonight – A Few Drive-By Showers

We may see a few light rain showers pass by this afternoon and tonight.

High-Res Rapid Refresh (HRRR) model at 7pm:

HRRR at midnight, followed by the RAP at midnight:

By 3am, more rain is on the way:

All rain will be moving east.

Saturday at 7 a.m. – The Rain Begins

European – overnight light rain, then this:

GFS – mostly dry overnight, then the rain comes:

Hi-Res NAM: Very few overnight showers, then heavier showers approach:

WRF:  Light overnight rain, then just like the above models, heavier rain starts to move in:

SREF:  Light overnight rain, but most of the Saturday morning rain stays north (this is a bit of an outlier):

Saturday 1 p.m. – It’s Probably Still Raining

European: Still raining:

GFS:  Raining pretty hard:

Hi-Res NAM:  An afternoon break in the rain!

WRF:  Soaker continues:

SREF:  Rain trying to move northeast of us. But, it’s still raining:

Saturday at 7 p.m. – About 1″ & Counting

European:  Yep. Still raining:

GFS: *Sigh* still raining:

Hi-Res NAM:  Fans of Franklin’s Main Street Festival & other assorted early evening activities need to cheer on this model. It clears us out!

WRF:  Tries to join the Hi-Res NAM movement to and give us a break in the rain for Saturday night:

SREF:  Still raining:

Sunday

We won’t go crazy with the models for Sunday. Expect some rain, and maybe a few thunderstorms, but it looks much drier than Saturday. Easily the best day for Franklin’s Main Street Festival and other outdoor activities, as long as you bring an umbrella.

5 Models Agree: Rain Saturday (& A Little More Rain Sunday)

Rain is very likely Saturday. The heaviest rain is forecast to fall Saturday morning, during the Country Music Marathon.  Here are the models:

European: Rain arrives Friday night and lasts through Saturday morning. By 7 a.m., the rain is along and south of I-40 (see below).

A soaking rain arrives by 1 p.m. Saturday. By Saturday night, it’s a light rain, which continues off and on until Sunday around dusk.

GFS:  Light rain arrives in the early Saturday morning hours. By 7 a.m. (see below), light rain continues to fall, while the heavier rain sits to our west.

Light rain of the off/on variety continues all day Saturday. The heaviest rain Saturday will be just to our south and could wander across I-40, but for now the GFS keeps it out of our area. A lighter rain event is expected Sunday, with off and on showers finally departing Sunday night.

WRF: Rain approaches early Saturday morning. It’s raining at 7 a.m. (see below).

Light rain continues off and on through Saturday. This model nudges the heavier rain south of us. The WRF model does not extend into Sunday.

Hi-Res NAM: This model sends in rain-out quantities of precip overnight Friday into Saturday morning. By 7 a.m., it hits us with another round (see below).

By Saturday night, it forms yet another (third) heavy rain swath across both counties.  Like the WRF, it does not extend into Sunday.

SREF: Like the other models, this one — at 10 a.m. — dumps just under a half-inch of rain on us:

NWS-Nashville:  Rain is “likely” all day Saturday. Over 1/2″ is expected from 7pm Friday through 7pm Saturday.  For Sunday, a “chance” of rain is indicated, but you can expect some off/on light rain.

Look for more details tomorrow and at @NashSevereWx.

Four Weather Models Think It’ll Rain Saturday

GFS and European wx models have been predicting rain Saturday morning. Today, there are other models now in range of the weekend. So, let’s dig in:

Country Music Marathon & Saturday Morning

Global Forecast System (GFS) forecasts light rain all morning. Earlier this week, this model was calling for 4 times as much rain.

European: very light, off/on rain. A dramatic improvement from earlier model runs, which predicted a lot more rain.

North American Model (NAM) at 7am and 10am likes our light rain chances:

7:00 am, Saturday, April 27, 2013
10:00 am, Saturday, April 27, 2013

Short Range Ensemble Forecast (SREF) at 7am and 10am get us wet, but most of the rain stays west:

7:00 am, Saturday, April 27, 2013
10:00 am, Saturday, April 27, 2013

BOTTOM LINE: the models are in decent agreement we will see off-and-on rain (mostly “on”) Saturday morning, but it won’t be a total washout. Expect around 0.25″ in the morning.

Saturday Afternoon Through the Rest of the Weekend

I won’t post all the images. Here’s a summary:

GFS: Off-and-on (mostly “on”) rain continues through the entire weekend.

European: Off-and-on (mostly “on” Saturday, “off” Sunday) continues through the weekend.

NAM:  Light rain through the weekend.

Weather Prediction Center:  keeps most of the rain south of us. We still get under 0.50″:

For Those Of You Who’ve Asked Me To Lie To You About Saturday’s Forecast

Earlier this week, the weather models were calling for a lot more rain. Now, they’re calling for a lot less. This is a clear trend guaranteed to continue. Therefore, by the time we get to Saturday, the models will call for sunshine.

For Those Of You Who Want The Truth

Rain is likely. So far, it looks like just a light rain, but it’s probably juuuust enough to rain out most outdoor sports activities (depending on the fields, of course).

It’s true — we can’t be absolutely sure. We remain 48+ hours away, and things could change. Tomorrow, even more weather models will be in range to give us a better sampling of what’s to come.  The closer we get to the event, the better the models perform.  But, if I had to bet on it, I’d bet on rain.  Sorry.

Another detailed forecast coming up tomorrow.