Flash Flood Warning 7, NWS Houston/Galveston, TX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
555 AM CDT Fri Jun 5 2026

...New AVIATION...

.KEY MESSAGES...

- Scattered to occasionally numerous showers and storms are
  expected for the remainder the week.

- Warm and humid conditions will prevail in between rounds of
  precipitation.

- Look for increasing winds/seas/rip current risk along the coast
  starting today through at least the weekend.

&&

.DISCUSSION...
Issued at 1225 PM CDT Thu Jun 4 2026

Scattered/numerous showers and thunderstorms will continue for the
through the weekend. A upper level low near Baja California and
western Mexico will eventually cutoff later today which will help
with having another focus for storms to initiate on. The best
diffluence is a bit just west of the area but could definitely see
storms starting in SE Texas from outflow boundaries from the west.
Besides that, the typical diurnally driven summertime convective
storm pattern continues with showers/storms near and off the coast
in the early morning hours, then more inland during the day when peak
heating nears and reaches its peak.
Rainfall wise, onshore flow continues to pump rich moist air from
the gulf so storms will be very efficient rainmakers. Due to the
scattered nature of the storms the past few days, total rain from
the past few days is quite spotty with most areas have already
seen 1-3 inches of rainfall in the past day or so with locally
higher totals in a few spots such as in the Galveston area. While
most places still have relatively low soil moisture, the hardest
hit areas from previous days could see any additional rainfall be
mostly runoff. So overall thinking the marginal risk of excessive
rainfall by WPC to be warranted for the next few days.

The rain and cloud cover should help cap the high temperatures in
most places but for anywhere that gets full sun could easily see
highs in the low 90s and heat index values in the upper 90s to
low 100s. Going into next week, a upper level ridge starts to
build out in the western continental US which will help reduce
but not completely eliminate storm chances. However with less
storms and cloud cover will mean more places will heat up, so take
precautions while outdoors especially if it will be prolonged.

&&

.AVIATION...
(12Z TAF Issuance)
Issued at 555 AM CDT Fri Jun 5 2026

Mixed bag of MVFR to VFR ceilings early this morning, and cannot
rule out intermittent periods of IFR ceilings through 15Z.
Scattered showers and isolated thunderstorms early this morning
will gradually expand in coverage going into the afternoon.
Reduced ceilings and visibilities are anticipated if heavy
downpours move over a terminal. Timing of TEMPOs and PROB30s
represent the most likely window for convection, but
showers/storms may occur before this as well. Coverage of
showers/storms decreases after 00Z, but may still have some
lingering isolated activity south of I-10 overnight into early
Saturday morning. Widespread MVFR to IFR ceilings are expected
overnight into Saturday morning. Expect winds to generally be
east-southeasterly around 7-10 kt throughout the day (outside of
any storms) then becoming light and variable later this evening.

Batiste

&&

.MARINE...
Issued at 1225 PM CDT Thu Jun 4 2026

Onshore flow continues for the coastal areas with winds just
touching or at small craft exercise caution criteria. That will
wane in the early morning hours today but additional rounds of
winds of 15 to 20 knots are possible through the weekend. Due to
the prolonged SE to E winds, additional water will be piling up at
the east/south facing shores. Rip current risk will steadily
increase through the weekend and into the early parts of next
week. Coastal flooding does not seem to be a concern right now but
a few of the lowest lying spots may see water during high tide.

&&

.HYDROLOGY...
Issued at 340 AM CDT Fri Jun 5 2026

A surface convergence zone near the I-45 corridor and south of I-10
lead to a pocket of 3-4+" rainfall totals on Thursday. This in turn
lead to minor/street flooding in portions of inland Galveston County
Thursday morning/afternoon. The HREF nailed the placement of this
rainfall maxima, so it's worth pointing out that there is potential
for another round of 3+" rainfall totals by this afternoon. This
time it is pinpointing areas in eastern Harris County and western
Chambers County as the most likely to see the highest rainfall
totals today. That being said, if you look at each HREF member
individually, you'll see that the placement of the rainfall maxima
varies a bit...but there is general consensus for it to occur
near I-10. Remember that portions of inland Galveston County are
fairly saturated following Thursday's rain, so if this area were
to see prolonged periods of heavy rainfall again today then there
would be a quicker transition to runoff.

Rainfall rates will continue to peak in the 3-4" per hour range in
the heaviest downpours. The potential for minor/street flooding
persists today and into the weekend. Portions of Southeast Texas
remain in a marginal risk (level 1 of 4) of excessive rainfall daily
through Sunday. There is one exception today though where portions
of the Brazos Valley are outlined in a slight risk (level 2 of 4) of
excessive rainfall due to its proximity with the approaching upper
level low. Be sure to stay up to date on the latest forecasts and
have multiple ways to receive alerts.

While we're talking about hydrologic matters, I might as well point
out that the San Bernard River at East Bernard (EBBT2) is currently
rising into action stage where it will crest later this afternoon.
All other river gauges are expected to remain below action stage at
this time, but we'll have to monitor local streams/bayous due to the
potential for 3+" rainfall amounts in or around Harris County
today. Remember that you can monitor updated river forecasts via
the NWS NWPS webpage (https://water.noaa.gov/).

Batiste

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)	  85  73  85  74 /  60  30  70  30
Houston (IAH)			  86  75  87  76 /  60  10  70  10
Galveston (GLS)			  87  81  87  82 /  30  10  30  20

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...None.
&&

DISCUSSION...BL
AVIATION...Batiste
MARINE...BL