May 2024

[tireman4]

Areas north of Houston got pounded last night and continue to do so this morning

[tireman4]

From Matt Lanza. This might be a headline as the day progresses...

[jasons2k]

It’s been pouring here for the last couple of hours. Not sure how much as the power is out and I can’t see the old plastic gauge on the fence. The end of my street is flooded - haven’t seen that since Harvey.
Lots of folks in the area without power including Oak Ridge High School.

[Cromagnum]

Getting to IAH and flying out on time is looking dicey...

[ejburas]

It’s been pouring here for the last couple of hours. Not sure how much as the power is out and I can’t see the old plastic gauge on the fence. The end of my street is flooded - haven’t seen that since Harvey.
Lots of folks in the area without power including Oak Ridge High School.

4.87" & counting in Woodson's Reserve. The drive to the office in The Woodlands in the thick on it was...interesting to say the least.

[jasons2k]

Hey look, if you’re in the front of The Woodlands, you’re technically not in a flood warning
(I’m joking of course…)

[869MB]

Great forecast discussion early this morning by the WPC emphasizing just how clueless most of the short-term models were depicting the convective evolution of this storm complex yesterday evening through this morning…

IMG_1964.png (79.64 KiB) Viewed 428 times

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
423 AM EDT Thu May 2 2024
Day 1
Valid 12Z Thu May 02 2024 - 12Z Fri May 03 2024

...THERE IS A MODERATE RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF
SOUTHEAST TEXAS...

...Southeast Texas...

A complex scenario currently unfolding across southeast TX within
the confines of areas that recently received very heavy rainfall
over the weekend. There are two distinct areas of interest with a
very heavy thunderstorm cluster focused east of Bryan/College
Station near Lake Livingston and surrounds. A secondary area is
currently moving through central TX Hill Country along the I-35
corridor between Austin/San Antonio. Hi-res deterministic has
struggled to gain footing on the exact evolution of these two areas
of focus with some missing the bill altogether, parlaying the
complexity of the setup. Based on current mesoanalysis, there is a
west to east SBCAPE gradient oriented from the Hill Country west of
I-35 over into southeast TX and the LA border. Rich, Gulf air has
been pulled northward within the north-south oriented 30-35kt LLJ
positioned over the eastern 1/3rd of the state. PWATs are analyzed
between 1.75-2" across the area of interest which has aided in
significant rainfall rates between 3-6"/hr at times within the
eastern most cell organization prompting totals to reach over 5"
within the areas impacted. This will only continue through the
morning as an expected cold pool is projected to push out of the
eastern thunderstorm complex and move to the southeast over the
course of the morning. Rates of over 2"/hr are almost a certainty
with the current environment with the 00z HREF signaling
neighborhood probabilities over 50% through much of the area
between Bryan/College Station down to just north of Beaumont. The
complex will eventually lose steam and rates will dwindle back to
manageable levels, but not before a swath of 3+" of precip is laid
in wake of the complex. This is not the entire story, however as
there are other questions that are having a hard time being
resolved.

There are some instances of a boundary being left behind as
remnants and helping to produce backbuilding across the same areas
that will have been hit recently. This comes in conjunction that
the energy left from the secondary complex over central TX
continuing its progression eastward as it maintains headway with
the mean steering flow. If that were to occur, additional rainfall
exceeding 1"/hr would be possible to add to the copious amounts
being dropped currently and through the morning. To make matters
more intriguing, some guidance has another complex developing out
over west TX that eventually grows upscale this evening and moves
over the same areas hit this morning. This is well documented on
the 00z HREF 3hr mean QPF fields which would exacerbate flooding
potential further. This is a significant impact scenario unfolding
due to the compounding nature of the precip over a water-logged
area after 6-12" of rain on Sunday, as well as any additional rains
within the latter part of the period.

With collaboration from impacted WFOs across southeast TX to the LA
border, a Moderate Risk was added to the new D1 with the western
extent over Brazos county, extending eastward to
Tyler/Hardin/Jasper near the LA state line. The southern periphery
was the hardest to nail down, but utilizing the HREF probability
fields and mean QPF footprint, have extended the MDT down to
Montgomery and Liberty counties with the extreme northeastern tip
of Harris county also included. A higher end SLGT is still forecast
around the periphery, including the Houston metro, but that comes
with uncertainty on the behavior of the outflow and eventual
progression of the complex, as well as magnitude as it moves
towards the Gulf coast.

[tireman4]

Movement South

[869MB]

IMG_1965.gif (75.64 KiB) Viewed 411 times

Mesoscale Precipitation Discussion 0209
NWS Weather Prediction Center College Park MD
1017 AM EDT Thu May 02 2024

Areas affected...Central to Upper TX Coast...Southwest LA...

Concerning...Heavy rainfall...Flash flooding likely

Valid 021415Z - 022000Z

SUMMARY...Significant flash flooding ongoing across southeast
Texas. While rates and areal coverage is expected to decrease
through the morning, high rain rates of 3"/hr and training over
the next few hours will pose additional areas of new considerable
flooding through the early afternoon.

DISCUSSION...
Leading edge...Louisiana...
GOES-E Visible/10.3um IR loop along with RADAR mosaic, depicts a
mature/intense MCS with well defined MCV over the Piney Woods of E
Texas moving into west-central LA with well defined bow extended
southward to the Sabine Pass/BPT. These bows have solid
southeasterly inflow with surface Tds in the mid 70s, while
boundary layer to 700mb moisture is pooled through the central LA
coast feeding northwest into the complex. Fairly saturated deep
profile from LCH still retains over 2000 J/kg of CAPE, to maintain
strong updrafts. However, forward propagation may limit overall
rainfall totals, but given 2-3"/hr rates, initially, post frontal
shield precipitation should maintain modest rain-rates (.5"/hr) to
allow for streaks of 2-4" totals across Southwest LA, favoring
further south where moisture convergence will maximize in
proximity to the higher Theta-E/more unstable Gulf air.

Southeast Texas including Houston...
While MCS cold pool is pressing the leading edge eastward, there
is currently a solid balance between weaker southward push of the
cold pool and southerly over-running ascent pattern that lays more
perpendicular to the outflow boundary. As such, an east-west
linear feature with embedded elements tracking more eastward have
resulted in greatest risk of considerable/significant flash
flooding over the last few hours. This is likely to maintain with
2-3"/hr rates over the next few hours with very slow southward
drift across Liberty/E Harris into Chambers county with spots of
additional 3-6" probable through to late morning/early afternoon.

GOES-Visible imagery shows the westward edge of the outflow
boundary is starting to become more shallow. However, the old
rear-inflow jet convergence axis developed a secondary convective
area, that generated a second cold pool that is dropping south to
reinforce and steepen the depth of the cold pool and likely
increase boundary layer to 850mb moisture convergence.
Additionally, VWP and GOES low level AMVs suggest weak veering and
confluence along this upwind edge as well. This strongly hints
at upstream new development over the next hour or so, as the area
has ample untapped/unstable and highly saturated low level
moisture (with sfc/850mb PW over 1"). This should allow for
rates of 2.5-3"+/hr rates but there is uncertainty of duration.

This uncertainty is driven by the strength of the upstream cold
pool undercutting and pressing best convergence southward into the
Gulf, reducing overall duration and therefore totals. This is the
ideal scenario and may result in localized 2-4" totals and spotty
flash flooding; however, there are model and observational trends
in RADAR/satellite imagery that may be much worst cast scenarios.
Worst case evolution would result from the development of a
meso-low generation along the initial outflow boundary in
proximity to the western Houston suburbs or points westward in
Austin/Colorado county that may stall southward cell motions
allowing for efficient 3"/hr rate cells to remain relatively
stationary for a few hours with spot totals of 6-10" by early
afternoon...which would result in significant/ considerable flash
flooding.

Gallina

ATTN...WFO...CRP...EWX...HGX...LCH...SHV...

ATTN...RFC...LMRFC...WGRFC...NWC...

LAT...LON 31749268 30959188 29619192 29659368 29189476
28539630 29769715 30359703 30529645 30699461
30959392 31479351 31739310

[Cromagnum]

Can't get a drop at the house, but hailing all around I AH and a cluster at the airport with flights. All because company flying me out insisted on nonstop flight which only goes out of IAH. If I had flown out of Hobby, I would have had a layover but would have had zero issues.

[djmike]

Its insane in Beaumont! Already on round 3 of heavy rain in 3 hours. Everything is flooded and roads are shutdown according to BPD. We are getting hit hard!

[Cromagnum]

Livingston completely underwater.

https://www.facebook.com/share/v/XFS51T ... tid=NXeFpL

[Cromagnum]

3 hour flight delay now. I don't know if this is an omen not to take this job or to gtfo of Houston.

[Goomba]

Its insane in Beaumont! Already on round 3 of heavy rain in 3 hours. Everything is flooded and roads are shutdown according to BPD. We are getting hit hard!

Yeah. Kind of crazy in this area. 85mph wind gust at the airport. Hail reports everywhere. Streets flooding. Medical Center of SETX reporting flooding. Outdoor furniture flying around. Many people wondering if it was a tornado.

[JDsGN]

4.87 peak inches per hour rainfall rate at my house currently! I feel sorry for everybody up north thats had these storms for hours now.

[ajurcat]

It just got very dark in the Jersey Village area. Street lights are on and wind is picking up.

[JDsGN]

The radar seems to be off by quite a bit. I know there's a delay but its pouring now in Katy at I10 and Mason and the line is still barely at FM 529 on the radar. Same thing when this rolled into Cypress and my rain gauge was showing 2" rainfall rates and it was still showing it was a ways off.

[Goomba]

Here's one video of many from the Golden Triangle. There are a lot posted on Greg Bostwick's post on Facebook about the 85mph wind gust. Greg is a longtime meteorologist for KFDM in Beaumont.

https://www.facebook.com/share/v/t5RWHC ... tid=oFDknk

[jasons2k]

Up to 7.54” here!!

[Cpv17]

Looks like the line is pushing south at a decent speed now. Still nothing at my house and I don’t really expect anything either.