AWUS01 KWNH 050402
FFGMPD
TXZ000-050800-

Mesoscale Precipitation Discussion 1128
NWS Weather Prediction Center College Park MD
1101 PM EST Mon Nov 04 2024

Areas affected...Central Texas

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

Valid 050400Z - 050800Z

SUMMARY...Flash flooding likely as storms producing up to 3 inch
per hour rainfall rates train over/near San Antonio and Austin.
Urban flash flooding an increasing concern.

DISCUSSION...A mesolow that has developed along a very slow moving
cold front draped over central Texas is tapping into 30-35 kt
southeasterly flow of Gulf moisture at 850 mb. This low and fronts
are providing ample forcing for thunderstorms that have a history
of producing 3 inch per hour rainfall rates northwest of San
Antonio. The storms are aligned parallel to the I-35 corridor. As
the storms grow upscale, they're backbuilding southwestward
towards the Rio Grande. For the very near-term there is little
pushing the front as the southeasterly flow ahead of the front is
being countered by 10-20 kt NNW flow of dry air behind the front.
Since these air flows are almost exactly antiparallel to each
other, they're supporting the mesolow that has formed west of San
Antonio. Further, they will work to keep the synoptic setup from
moving too much for the next few hours.

An approaching upper level shortwave over northwest Texas is
gradually moving east towards the storm complex. This will
increasingly work to push the complex of storms towards the east
faster, which will consequently reduce the flash flooding threat
with time. CAMs guidance is in good agreement in this scenario,
albeit with variable timing due to poor handling of the current
storms.

The storms are currently over Austin and are just about into the
San Antonio metro at the time of this writing. Expect a
multiple-hour period of heavy rain associated with the storms.
Considering the reduced FFGs associated with the urban centers,
urban flash flooding is an increasing concern over the next few
hours until the aforementioned shortwave moves the storms east of
the I-35 corridor.

Wegman

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!=
DZ3fjg!61EcCrLagqB-PnpGFdGXXXNvzO_9Ansvi4vY338kfBocDm8ZRg_LpXoE_OTgMGb_gFMz=
nb69J93CZIYdRcgzIQtA42k$  for graphic product...

ATTN...WFO...CRP...EWX...FWD...HGX...

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

LAT...LON   30859753 30659687 29829679 28959744 28619830=20
            28489942 28939983 29159952 29379924 29809881=20
            30539813 30819789 30829787=20

=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to
https://lists.illinois.edu and use the "Unsubscribe" link.  Otherwise email
Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.20-Linux