AWUS01 KWNH 160925
FFGMPD
LAZ000-TXZ000-161524-

Mesoscale Precipitation Discussion 0426
NWS Weather Prediction Center College Park MD
525 AM EDT Tue Jun 16 2026

Areas affected...portions of the Texas Gulf Coast and surrounding
areas

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

Valid 160924Z - 161524Z

Summary...Scattered thunderstorms initially over Gulf Waters were
beginning to move/develop northward toward land areas along the
Texas Coast. These trends should continue over the next 3-6
hours, with flash flood potential increasing especially over
sensitive and urbanized areas.

Discussion...Recent radar mosaic imagery depicts a gradual, yet
slow increase in convection over land areas along the Texas Coast
-- particularly near Port Arthur, Port Lavaca, and southwest of
Galveston. Earlier convection over these areas has departed, and
weak southerly low-level flow (10-15 knots per mesoanalyses) was
enabling a gradual northward development of abundantly
moist/unstable air (1500+ J/kg MLCAPE, 2.5 inch PW) into more of
southeast Texas with time. These moisture values and weak
low-level confluence (bolstered by increasing 850mb flow over the
western Gulf) will support increasing convective coverage over
time, with slow storm motions and favorable thermodynamics
fostering occasional rain rates to 3 inches/hr at times through
15Z/10a central.

These rain rates will fall over areas that have been wet recently,
with widespread 2-5 inch rainfall totals over the past 24 hours
resulting in lowered FFG thresholds (close to zero near Corpus
Christi and Paladios - closer to 1-1.5 inch/hr elsewhere). Storms
will have potential to readily exceed FFG in many areas, and urban
flash flooding is a possibility as storms close in on Houston
Metro later this morning. Flash flooding is likely across the
entire discussion area in this scenario, and significant impacts
cannot be completely ruled out.

Cook

ATTN...WFO...BRO...CRP...EWX...HGX...LCH...

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

LAT...LON 30409437 30239377 29739389 29319466 28689567
28119673 27399725 26789750 26869791 27489801
28389773 29149709 29839587

= = =

AWUS01 KWNH 161025
FFGMPD
LAZ000-TXZ000-161623-

Mesoscale Precipitation Discussion 0427
NWS Weather Prediction Center College Park MD
624 AM EDT Tue Jun 16 2026

Areas affected...portions of Southeast TX & Southwest LA

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

Valid 161023Z - 161623Z

Summary...Thunderstorms with heavy rainfall are moving into the
region from the southwest. Hourly rain amounts to 3" with local
amounts to 6" are possible, which would lead to scattered
instances of flash flooding.

Discussion...An effective front/thermal boundary is draped near
and south of I-10/I-12 in Louisiana. Precipitable water values
are 2.4-2.5" per GPS data. An ML CAPE gradient exists across the
region, with 500-1500 J/kg shown by SPC mesoanalyses. Effective
bulk shear of 25-30 kts exists, enough to organize convection. An
offshore pocket of convection has created some CIN offshore
Cameron, but the thunderstorm band appears to be less
solid/cohesive as of late on radar imagery. Aloft, there's some
indication that a weak shortwave is moving across OK and northern
TX on water vapor imagery.

There is more than the usual uncertainty in this region regarding
heavy rain prospects. The wettest guidance shows 7-10" during the
next six hours across Acadiana, but that guidance also has no
offshore convection. Recent HRRR runs show nothing at all, but
radar trends are not their friend. Given the ingredients, hourly
rain amounts to 3" and local totals to 6" are considered possible.
While portions of this region have been spared heavy rainfall,
the expected magnitude would exceed the highest flash flood
guidance in the region and be a problem in urban areas.

Roth

ATTN...WFO...JAN...LCH...LIX...

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

LAT...LON 31049193 31029165 30269144 29519159 29489211
29719327 29639405 30369455 30909388

$$


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