Mesoscale Precipitation Discussion 0909
NWS Weather Prediction Center College Park MD
401 PM EDT Tue Aug 30 2022
Areas affected...Southeast TX
Concerning...Heavy rainfall...Flash flooding possible
Valid 302000Z - 310000Z
SUMMARY...Ongoing thunderstorm activity across southeast Texas may
result in additional flash flooding through late afternoon.
DISCUSSION...A 500mb low over West Texas is providing some
diffluent flow aloft while 850mb winds continue to funnel rich
Gulf of Mexico moisture into southeast Texas. This is in part due
to a 500mb ridge along the central Louisiana coast, that in tandem
with the upper low in West Texas, is resulting in a convergence
zone over southeast Texas. 19Z surface analysis showed a surface
low in central Texas with a pair of surface troughs acting as
triggers for ongoing areas of convection. SPC RAP mesoanalysis
showed a reservoir of 2.2-2.3" PWs throughout the highlighted
region, as well as MLCAPE between 1,000-2,000 J/kg. 850-300mb mean
wind speeds are ~5 knots and mean cloud layer RH values are
averaging close to 90%.
Ongoing storms have begun to propagate west towards central Texas
where one surface trough is located while storms continue to form
along another surface trough west of Houston. 17Z HRRR showed
storms gradually dissipating around 00Z with the atmosphere being
overworked and due to the loss of daytime heating. However, storms
associated outflow boundaries may help to produce additional
storms not long after sunset. The 12Z HREF displayed probabilities
of 3-hr QPF > 3-hr FFGs as high as 45-50% west of Kileen. FLASH
CREST max unit stream flow highlighted Kileen as seeing 300-700
cfs/smi due to storms recently passing through the area. MRMS
instantaneous precip rates were as high as 4-5"/hr in some cases,
but most areas can expect hourly rainfall totals in the 2-3"/hr
range. This shows the type of rapid onset flooding that can occur,
especially in urbanized communities that contain a greater
concentration of hydrophobic surfaces. Low lying, poor drainage
areas are also susceptible to flash flooding the remainder of the
afternoon.
Mullinax
ATTN...WFO...CRP...EWX...FWD...HGX...SJT...
Carla/Alicia/Jerry(In The Eye)/Michelle/Charley/Ivan/Dennis/Katrina/Rita/Wilma/Humberto/Ike/Harvey
Member: National Weather Association
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jasons2k wrote: ↑Tue Aug 30, 2022 4:59 pm
Yep, once again….
Any Aggies recently settle into the area, recently? Because that is one helluva AggieDome. I can't believe those cells moving just west of I-45 missed you.
1.72 in of rain today in CLL. Salvation at last. Now I can begin preparations for brown patch season.
jasons2k wrote: ↑Tue Aug 30, 2022 4:59 pm
Yep, once again….
Any Aggies recently settle into the area, recently? Because that is one helluva AggieDome. I can't believe those cells moving just west of I-45 missed you.
1.72 in of rain today in CLL. Salvation at last. Now I can begin preparations for brown patch season.
I’m glad you finally hit the jackpot!
Yeah, every cell that approached me today fell apart, no matter which direction. And then another would reform on the other side of me.
My step-mother and sister moved here back in May. They asked me last week "What is up with the rain in this area? It's like this one neighborhood has a forcefield over it that just zaps anything headed this way"
I said "Basically, yep - welcome to the neighborhood!"