786
AWUS01 KWNH 041433
FFGMPD
TXZ000-042000-

Mesoscale Precipitation Discussion 0586
NWS Weather Prediction Center College Park MD
1033 AM EDT Fri Jul 04 2025

Areas affected...Hill Country and Edwards Plateau of south-central
Texas...

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

Valid 041430Z - 042000Z

SUMMARY...Slow moving MCC continues to compound significant flash
flooding with some areal expansion expected over next few hours.
WPC upgrade to Moderate Risk.

DISCUSSION...GOES-E WV suite depicts the fairly symmetric MCC
remains ideally within anticyclonic wedge; while not very strong
outflow is sufficient with impressive transverse banding features
along much of the northern hemisphere of the circulation and with
the persistent strong updrafts/latent heat release the MCV
continues to remain strong near the McCulloch/Saba/Mason county
intersection.  Regional RADAR mosaic denotes this with impressive
arched convective band along the effective cold front within the
western quadrant of the MCC from Mason to Sutton county and VWP
shows solid warm advective profile off the Rio Grande confluent
across central South Texas further expanding effective warm
frontal banding like features along and downstream to the SE of
the MCV.  Upstream well of continued very moist and unstable air
with TPW values over 2.25" and MLCAPE gradient of 1000-2000 J/kg
along the southwest to southern side of the circulation.  This
will support cells capable of 2-3"/hr

As the MCV wobbles and confluence increases into the WAA, the band
will once again shift across the Guadalupe River Valley likely to
induce another wave of flash flooding conditions.  While Hi-Res
CAMs continue to suggest a weakening phase over the next few
hours, the upstream inflow and potential for upstream development
along the WAA regime may result in relatively with south-southwest
propagation equal/stronger than 10-15kt inflow resulting in
stationary cells with spots of additional 4-6" possible.  As such
significant to catastrophic flash flooding is likely to continue
with potential to expand along the southern periphery of the MCC.


Gallina

...Please see www.wpc.ncep.noaa.gov for graphic product...

ATTN...WFO...EWX...SJT...

ATTN...RFC...FWR...NWC...

LAT...LON   31449905 30979848 30689768 29959762 29429807
            29189869 29099927 29310003 29940063 30470084
            30860075 31040040 31299992 31429983