July 2021

[Rip76]

Interesting set up here.

I would guess in between the two models.

[Stratton20]

Wouldnt be shocked to see Houston be included in the flash flood watch soon, man if this low ( not saying it will) got into the gulf, we could easily be in some serious trouble, its got a well defined spin and lots of convection, we will see, regardless someones going to end up with a foot or more of rain the next 2-3 days

[don]

Don't be fooled by the dry weather today...As it is actually allowing the atmosphere to recover, and may be partially why models have gotten more aggressive with rainfall accumulation over the next couple of days.

[Stratton20]

It looks at least to me like their might be a little vorticity spin in the gulf within that convection

[Kingwood36]

What is the definition of a core rain event?

[don]

Core rain events happen with tropical systems or warm core lows.When the heat from the day releases back into the atmosphere at night.And creates thunderstorms with very high rainfall rates that sit over an area for an extended time.As the tropical low helps to pull moisture in from the gulf,which allows the storms to persist without dying down quickly.Allison,Harvey,Imelda,and Beta are examples of core rain events that have happened over the last 20 years locally.

[Stratton20]

Definitely becoming more concerned about what could unfold tommorow night- Friday

[txbear]

Core rain events happen with tropical systems or warm core lows.When the heat from the day releases back into the atmosphere at night.And creates thunderstorms with very high rainfall rates that sit over an area for an extended time.As the tropical low helps to pull moisture in from the gulf,which allows the storms to persist without dying down quickly.Allison,Harvey,Imelda,and Beta are examples of core rain events that have happened over the last 20 years locally.

This is an awesome explanation, don. Kingwood - I've been trying to get the same question answered since Harvey, so thanks for asking.

So what you're saying is warm core lows (like tropical systems) essentially draw heat down to the surface during the day, until an inversion occurs and that drawn down heat is able to rise into the atmosphere. This lift, in and of itself without the daytime sun, is sufficient to initiate and sustain intense rain storms with the moisture influx from the gulf.

This is opposite of cold core (or what we would normally associated with any other low transiting the continent) which needs the daytime sun and heat to create lift to offset the cold air being drawn down and released. There's a whole other dynamic with sustained storms along say a front in the middle of the night...but that's another scientific discussion.

[Stratton20]

12z Euro seems to be underestimating the potential core event tommorow, expect some big surprises yall

[Rip76]

Looking at satellite, it appears to be starting the move West.

[Cpv17]

Looking at satellite, it appears to be starting the move West.

We probably would need it to move further north, not west. Correct me if I’m wrong though.

[Stratton20]

Rip76 na its still stationary, the low hasnt moved much, tbh its very hard to tell if its moving at all or which way its moving

[Cpv17]

12z Euro seems to be underestimating the potential core event tommorow, expect some big surprises yall

The Euro has not handled this event very well.

[Stratton20]

CPV17 I agree, we will have to see what happens with the core rain event potential tommorow night, if we see any sort of rain band set up like what’s happening in south texas, we could see some big problems

[DoctorMu]

Looks like a Nowcasting situation. Models are a bit busty.

[DoctorMu]

Looking at satellite, it appears to be starting the move West.

Nice visualization of the south Texas trough. Slow westward movement

https://earth.nullschool.net/#current/w ... 5.80,3251\


https://www.star.nesdis.noaa.gov/GOES/s ... &length=24

[Stratton20]

18z HRRR run pulls the low to the North and then sits it pretty much in the vicinity of where harvey stalled , seems models are having a hard time figuring out what this low wants to do

[djmike]

Looking at radar it looks like another circulation just under the L in Tx by MX.

[Stratton20]

Djmike MX?

[davidiowx]

This radar loop shows the circulation quite well. It doesn't appear to be moving much at all. If anything, it has slightly jogged westward but starring at it for long enough, you start to see things that may not be tricking the eyes.

https://weather.cod.edu/satrad/nexrad/i ... 00-usa-rad