AWUS01 KWNH 250432

FFGMPD

TXZ000-251000-



Mesoscale Precipitation Discussion 1210

NWS Weather Prediction Center College Park MD

1231 AM EDT Sat Oct 25 2025



Areas affected...Eastern & South-Central Texas...



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



Valid 250430Z - 251000Z



SUMMARY...Upstream QLCS have slightly favorable training

environment to maintain longer rainfall duration for spots of 2-4"

totals and scattered possible incidents of flash flooding through

late overnight period.



DISCUSSION...Regional RADAR mosaic shows a mature QLCS rapidly

advancing across North Texas into the Heart of Texas increasing in

forward speed, while strong inflow vector becomes parallel to the

line reducing overall convergence.  However, GOES-E WV suite

denotes main southern stream shortwave lifting northeast through

the Red River Valley with trailing mid-level trough axis back

toward the Big Bend of the Rio Grande Valley.  Strong

diffluent/split flow from 80kt sub-tropical jet streak, generally

aligned along South Texas and through the Upper Texas Coast

combined with right entrance to 70kt south to north polar jet

streak across the Big Country allows for increasing divergence in

proximity to the trailing convective outflow (southern edge of

strong 1015 Meso-high). 



Strong surface to 925 south-southeasterly flow at 10-20kts is

pumping low 70s Tds and increasingly unstable air off the western

Gulf generally orthogonal to the orientation of the

trough/convergence axis.  This is providing more than ample strong

moisture flux convergence for a strengthening cluster along the

upwind edge with overshooting tops to -70C.  Pooled moisture is up

to 1.5" through depth, though maximized in the lowest portion of

the column allowing for efficient rainfall production with

1.75-2"/hr rates.  Downstream along the northeast edge, isentropic

WAA is providing some scattered towers pre-wetting the soils as

the peak cores rapidly advance.   While forward speed will limit

overall totals, the combination of prolonged moderate rainfall

with peak rates up to 2" (with 03z HRRR suggesting 1.25"/15

minutes) may be intense enough to overcome the regionally high FFG

values.  A few urban locations along the path would be more prone

to these rates for scattered flash flooding concerns particularly

San Antonio Metro.



Of note, but a bit less certain, in the wake of the cluster there

is a solid upstream remaining pocket of 1000-1500 J/kg of MUCAPE

through the Big Bend/Lower Pecos Valley.  While mid-level

shortwave and ideal jet diffluence will be downstream, low level

flow intersecting the flanking outflow has some solid potential

for redevelopment.  While not likely as strong as the initial

cluster any totals of 1-2" additional would further expand those

areas that were close to exceeding with the initial round and

maintain a risk of localized flash flooding for a few additional

hours. 



Gallina



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



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



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



LAT...LON   30869829 30849640 29899569 28839627 28649903 

            28880036 29250109 30000129 30189935