September 2019 - Warm End of September

[davidiowx]

thread https://twitter.com/pppapin/status/1173699306039021568

no invest, no meso floater

Levi has a manual floater up...

https://www.tropicaltidbits.com/sat/sat ... product=ir

Looks like a decent blow up of convection starting around 28N and 93W,,

[Cpv17]

GFS is now leaning towards the NAM/ICON with the heavier totals towards the east.

[sambucol]

GFS is now leaning towards the NAM/ICON with the heavier totals towards the east.

I’m in Baytown. How heavy is the heavier totals?

[srainhoutx]

thread https://twitter.com/pppapin/status/1173699306039021568

no invest, no meso floater

Levi has a manual floater up...

https://www.tropicaltidbits.com/sat/sat ... product=ir

Looks like a decent blow up of convection starting around 28N and 93W,,

Click on the visible imagery (bottom tab below loop). Very evident to me we have a broad low around 28N and 94W

[unome]

good of Levi to put that up

slider: https://rammb-slider.cira.colostate.edu ... 530&y=5334

[sau27]

GFS is now leaning towards the NAM/ICON with the heavier totals towards the east.

I’m in Baytown. How heavy is the heavier totals?

18z GFS actually brings down rainfall totals. Keeps highest amount confined basically to the beach and around 6-7 inches at that.

Again, this is going to continue to bounce around for the next few days.

[stormlover]

https://www.tropicaltidbits.com/analysi ... 91618&fh=6

Gfs Legacy hits Beaumont hard

[stormlover]

https://weather.cod.edu/satrad/?parms=l ... =undefined

Strain, what do u think?

[jasons2k]

Well at least it cooled off!! It's a very pleasant 82F here now. My high temp earlier today was 97!

[Katdaddy]

Our Houston-Galveston NWS sums the knowns and unknowns very well in this afternoon’s Area Forecast Discussion and why need to be weather aware through the rest of week:

.MID TERM [Tuesday Night Through Thursday]...
What we know:
- Ground will gradually become increasingly saturated with periods of rainfall and more prone to runoff.
- Upper low will make its way northward into southeast Texas, but ikely stall and meander over the area due to higher pressure to the north.
- Moisture levels will be near record peak values recorded this time of year. Rain rates of 1-3"+ per hour are possible at times. Heavy rain in a short amount of time will be the primary trigger for street flooding and rises on area creeks, bayous and rivers.
- A weak surface low will slowly move northward from the Coastal Bend to near the Matagorda Bay area Tuesday night and Wed morning setting the stage for the first potential round of heavy rainfall...possibly in the form of training convective bands closer to the circulation itself...gradually spreading out thru the day with heating.
- In very general terms, the surface low will meander northward Wed & Thur...possibly situated between the Brazos Valley and I-45 late in the period.
- Multiple rounds of precipitation are expected with some
intermittent breaks in between.
- There will be changing, potentially large run-to-run swings of model solutions. Don`t focus on just one. Just know the overall conditions are favorable for heavy rain which could cause flooding.

What are some of the unknowns:
- Just how organized or unorganized atmospheric conditions line-up for prime and/or significant amounts of rain.
- Specific rain amounts. There will be several inches spread out over several days. Focus on the impacts!
- Specific timing/location of the periods of heaviest rainfall.
Can occur at any time and any place. They`ll be dependent on several variables which can be difficult to determine even 6-12 hours out. Just know there are signals there for significant rain and associated flash flood impacts.
- Specific river/creek/bayou impacts. It`ll be dependent on where and how much rain falls. Rises and flooding impacts can be expected where the heaviest rain occurs.

[Cpv17]

Our Houston-Galveston NWS sums the knowns and unknowns very well in this afternoon’s Area Forecast Discussion and why need to be weather aware through the rest of week:

.MID TERM [Tuesday Night Through Thursday]...
What we know:
- Ground will gradually become increasingly saturated with periods of rainfall and more prone to runoff.
- Upper low will make its way northward into southeast Texas, but ikely stall and meander over the area due to higher pressure to the north.
- Moisture levels will be near record peak values recorded this time of year. Rain rates of 1-3"+ per hour are possible at times. Heavy rain in a short amount of time will be the primary trigger for street flooding and rises on area creeks, bayous and rivers.
- A weak surface low will slowly move northward from the Coastal Bend to near the Matagorda Bay area Tuesday night and Wed morning setting the stage for the first potential round of heavy rainfall...possibly in the form of training convective bands closer to the circulation itself...gradually spreading out thru the day with heating.
- In very general terms, the surface low will meander northward Wed & Thur...possibly situated between the Brazos Valley and I-45 late in the period.
- Multiple rounds of precipitation are expected with some
intermittent breaks in between.
- There will be changing, potentially large run-to-run swings of model solutions. Don`t focus on just one. Just know the overall conditions are favorable for heavy rain which could cause flooding.

What are some of the unknowns:
- Just how organized or unorganized atmospheric conditions line-up for prime and/or significant amounts of rain.
- Specific rain amounts. There will be several inches spread out over several days. Focus on the impacts!
- Specific timing/location of the periods of heaviest rainfall.
Can occur at any time and any place. They`ll be dependent on several variables which can be difficult to determine even 6-12 hours out. Just know there are signals there for significant rain and associated flash flood impacts.
- Specific river/creek/bayou impacts. It`ll be dependent on where and how much rain falls. Rises and flooding impacts can be expected where the heaviest rain occurs.

That’s an excellent write up!

[jasons2k]

They keep saying moisture will be near "record levels" for "this time of year".

It's September. It's THE time of the year for high levels of moisture. It's kinda like when they say it's going to be "unseasonably cold" in the middle of December. Like there's another season besides winter for cold weather.

I think Mets sometimes struggle with the nuances of the English language.

[Cpv17]

I feel like the NAM 3km has a pretty good handle on this right now and it says the heaviest rains will be just to my east. Only has about 1-2” for me, but I’m only about 20 miles away from 8+”.

[don]

They keep saying moisture will be near "record levels" for "this time of year".

It's September. It's THE time of the year for high levels of moisture. It's kinda like when they say it's going to be "unseasonably cold" in the middle of December. Like there's another season besides winter for cold weather.

I think Mets sometimes struggle with the nuances of the English language.

When they are referring to moisture they mean precipitable waters which some of the models show approaching 3 inches, that's very high and is record territory.

[jasons2k]

They keep saying moisture will be near "record levels" for "this time of year".

It's September. It's THE time of the year for high levels of moisture. It's kinda like when they say it's going to be "unseasonably cold" in the middle of December. Like there's another season besides winter for cold weather.

I think Mets sometimes struggle with the nuances of the English language.

When they are referring to mousture they mean precipitable waters which some of the models show approaching 3 inches,thats very high and record territory.

I understand that - it was about the "this time of year" comment. It's September, not January. They could simply say "near record levels" period.

[swell]

They keep saying moisture will be near "record levels" for "this time of year".

It's September. It's THE time of the year for high levels of moisture. It's kinda like when they say it's going to be "unseasonably cold" in the middle of December. Like there's another season besides winter for cold weather.

I think Mets sometimes struggle with the nuances of the English language.

Daily max Precipitable Water from past LCH soundings in the next couple days was 2.35. Don't see the problem
https://www.spc.noaa.gov/exper/soundingclimo/

[djmike]

Picked up over 1” today from Mr. Lows outer rain bands. 3 more days to go and will prob see a lot more. Have a gut feeling the core rains will meander east a bit on qpf but just my opinion. Just from seeing core originally started out over corpus yesterday and now core will be houston. Thats quite a shift. We will see....

[unome]

They keep saying moisture will be near "record levels" for "this time of year".

It's September. It's THE time of the year for high levels of moisture. It's kinda like when they say it's going to be "unseasonably cold" in the middle of December. Like there's another season besides winter for cold weather.

I think Mets sometimes struggle with the nuances of the English language.

for reference, from https://www.spc.noaa.gov/exper/soundingclimo/

Screenshot_2019-09-16 Storm Prediction Center Sounding Climatology Page - Copy.png

Screenshot_2019-09-16 Storm Prediction Center Sounding Climatology Page - Copy.png

[Tx2005]

How far east have things shifted today? I’m assuming Eastern Harris County is in the thick of things now?

[Andrew]

How far east have things shifted today? I’m assuming Eastern Harris County is in the thick of things now?

Nothing has changed today from earlier this morning. Most models indicate widespread 5-8 inches with isolate pockets of 15 inches possible. Unfortunately, forecasting where the heaviest rain will fall will likely be a "nowcast" type of situation where we have to wait for it to start raining or at least get a couple of hours out. Also, expect multiple rounds of rain with the largest areas of concern being Tuesday night and Wednesday night.