AWUS01 KWNH 241404
FFGMPD
ARZ000-TXZ000-OKZ000-241930-

Mesoscale Precipitation Discussion 1185
NWS Weather Prediction Center College Park MD
904 AM EST Tue Dec 24 2024

Areas affected...North/Northeast Texas...Portions of SE OK & SW
AR...

Concerning...Heavy rainfall...Flash flooding possible

Valid 241405Z - 241930Z

SUMMARY...Increasing convective activity with potential of
1.5"+/hr rates with back-building and short-term training
potential may exceed FFG, especially near urban centers resulting
in possible localized flash flooding.

DISCUSSION...GOES-E 10.3um loop shows convection breaking out
along the frontal zone across North Texas into the Red River
Valley with steady increasing lightning detection within most
active cores, particularly along the upstream edge.  Surface
analysis denotes a weak surface low near F02 with stationary front
meandering through the Red River with northern stream cold front
slowly dropping southwest across eastern portions of the Big
Country back through the Concho Valley; south of which, returning
Gulf moisture is starting to encroach with reinforcing shot of
enhanced theta-E with mid 60s Tds in the southern Triangle lifting
north as well.  CIRA LPW shows a slug of detached mid-level
moisture from the Pacific stream pooled along the frontal boundary
in association with a weak shortwave over northeast OK.  GOES-E WV
suite also denotes, core of northern stream upstream larger scale
wave is starting to dig across the Central High Plains;
effectively strengthening the low level flow to further enhanced
deep moisture convergence over the midday into afternoon hours.=20
This has resulted in a 500-1000mb thickness ridge over E TX that
is supporting a veered propagation vector field that will align
with deeper layer steering for at least a few hours across the Big
Country into Northeast Texas providing a solid potential for 1)
training of convection but 2) increasing upstream moisture
convergence and steepening lapse rates (with modest mid-level
drying from the southwest) to support increasing instability and
convergence for development/backbuilding.=20

In the short-term, the cells are converting modest instability
with MLCAPE increasing to about 500-1000 J/kg along the upwind
edge with downstream cells likely becoming a bit more elevated
with MUCAPE pool of 500 J/kg to maintain more scattered/isolated
cells into SW AR with time.   Solid deep layer convergence and
total PWats of 1.25" (though bulk of .75"+ at sfc/850mb layer)
will allow for some intense rainfall production.  RADAR estimates
of 1.5"/hr have already be observed with potential for additional
capacity if the training/repeating corridor saturates through
depth.

A balance of unidirectional SSW steering and some outflow/cold
pool propagation southeastward may reduce ideal training setup
given weaker instability totals, but risk of 2-3" totals in 2-3
hours may result in localized flash flooding.  This only increases
in proximity to DFW urban corridor, where risk goes up and may be
the only location that these totals may overcome the higher FFG
given drier 30-50% soil saturation environment along and east of
I-35...though saturation increases toward the Texarkana region,
hence the inclusion of the area at this time. As such, a incident
or two of flash flooding is considered possible in the near-term.=20


Gallina

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!=
DZ3fjg!_0Q92CWVPg1fjm9lGxImqhznbTs7LPIRekyUZg4JCUizngcJcy2cG-pCf62ScdIFVIjE=
ApfoMoqXUQ4VO-_ZsLljK8Q$  for graphic product...

ATTN...WFO...FWD...LZK...OUN...SHV...TSA...

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

LAT...LON   34729428 34249336 33499368 32819472 32049641=20
            31759835 32379852 33159788 33879686 34449568=20
=20=20=20=20=20=20=20=20=20=20=20=20

=3D =3D =3D
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