AWUS01 KWNH 090725
FFGMPD
LAZ000-TXZ000-091200-

Mesoscale Precipitation Discussion 1143
NWS Weather Prediction Center College Park MD
225 AM EST Sat Nov 09 2024

Areas affected...Far Southeast TX...Southwest LA...

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

Valid 090725Z - 091200Z

SUMMARY...Persistent redeveloping warm cloud tropical showers
likely to proliferate over the next few hours with localized
totals over 4" possible.  Flash flooding is becoming increasingly
possible through early morning.

DISCUSSION...GOES-E 10.3um and LCH RADAR loop shows a few shallow
topped cells across Hardin/Jefferson county that are starting to
expand in coverage along a boundary layer convergence axis from
Galveston Bay north-northeastward eastward of the approaching cold
front.  VWP and RAP analysis 850mb analysis shows 15-20kts of ESE
flow slowing and stretch both northward toward the exiting
northern stream shortwave associated with diffluent portion of the
cyclonically curved 3H jet streak over E TX, and peripheral
influence approaching tropical cyclone Rafael.  This is resulting
in solid speed convergence at the nose/pool of enhanced surface to
850mb moisture (which further totals to near 2-2.2").  Proximity
to the warmer theta-E off the Gulf, convective development has
been fueled by sufficient 1500-2000 J/kg SBCAPE. While the overall
depth of the updrafts are not very deep, the overall moisture flux
convergence is sufficient for 2"/hr rates.=20

Localized storm effects and approach of the cold front also have
been aiding some flanking line development to counteract the slow
north-northeast cell motions and allowing for increased rainfall
totals over the last few hours in Hardin county.  While much of
the Hi-Res CAM suite has been deficient of development, the
placement in those hi-res CAM fields seem to be displaced west and
reduced in overall deeper layer convergence.  One solution that
appears to have this stronger convective axis is the FV3 CAM,
which does suggest an narrower overall distance in the low level
convergence coverage.  Confidence is not very high given the lack
of guidance support but observational trends.  As such, flash
flooding is considered possible, intense, but localized.=20=20=20

Gallina

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!=
DZ3fjg!9Z4k6xfze70Dcd_-n1561acaO5OLboDz9elAXcLpq93-9bNwOaWMmyF8gbLAjhWPv0gQ=
Dz6IHVAeM1_RtGSKySad9-4$  for graphic product...

ATTN...WFO...HGX...LCH...

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

LAT...LON   31039431 31039338 30609305 29929324 29599390=20
            29449446 29179529 29929534 30729490=20

=3D =3D =3D
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