787
FXUS64 KHGX 092054
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
354 PM CDT Thu May 9 2024

...New SHORT TERM, LONG TERM, MARINE, HYDROLOGY...

.SHORT TERM...
(This evening through Friday Night)
Issued at 354 PM CDT Thu May 9 2024

Showers and thunderstorms are developing over the central and north
central portions of Texas ahead and along a cold front this
afternoon. These storms are expected to continue east southeastward
and make it into the Brazos Valley and Piney Woods region later this
evening into early tonight. Although the cap still remains fairly
strong for much of Southeast Texas, it is expected to weaken later
today. Forecast soundings still show CAPE values of over 4000 J/kg,
in particular for areas north of I-10. In addition, they indicate
SFC-6km shear values of 45-55 kts, steep mid level, and DCAPE values
of over 1000 J/kg. PWs will increase to around 1.8 inches this
evening and dewpoints will be in the mid to upper 70s. Overall, any
storms that do make it into the aforementioned area has the
potential to remain strong to severe and could result in large hail
and damaging winds. An isolated tornado cannot be ruled out either.

One thing to note is the small potential for a few vort maxes to
move across Southeast Texas early this evening, which could lead to
locally driven, isolated storms...if they manage to overcome the
cap.

SPC now has placed an Enhanced Risk (threat level 3 of 5) north of a
line from Washington County into northern Liberty County. A Slight
Risk (threat level 2 of 5) exists southward of there to roughly
along the I-10 corridor and a Marginal Risk (threat level 1 of 5)
exists for the rest of the area except around Matagorda Bay.

Be prepared and have multiple ways of receiving warnings!

Storms are expected to have either dissipated or moved eastward and
away from our region before midnight, ahead of the next cold frontal
passage. The front is progged to reach the coastal areas during the
late night hours. On Friday, tranquil but breezy conditions are
expected as gusty north to northeast winds develops in the wake of
the front. Slightly "cooler and drier" air will filter in across the
area and result in partly cloudy skies and highs in the low to mid
80s over the Brazos Valley and Piney Woods region and in the mid to
upper 80s elsewhere. The lows Friday night into early Saturday
morning will be in the low to mid 60s over the Brazos Valley and
Piney Woods region and in the upper 60s to low 70s elsewhere.

24

&&

.LONG TERM...
(Saturday through next Wednesday)
Issued at 354 PM CDT Thu May 9 2024

Though low levels will be drier on Saturday than they have been
the past several days, we still anticipate some mid level
moisture & cloud cover streaming overhead. Some of the
deterministic models show some decent shortwave energy and lift
passing across the southern parts of the area, so went ahead and
included some low POPs in case we see some associated sprinkles or
light rain.

Heading into Saturday night and Sunday, the remnant boundary in
the Gulf will move back inland as a warm front. With it comes some
deep Gulf moisture as PW`s climb to around 2.2" across a good part
of the region. A zone of low level speed convergence sets up and
combined with additional passing upper impulses we anticipate
increasing shower and thunderstorm coverage on Mother`s Day.
Somewhat similar setup for Monday as mid-upper trof makes its way
across the Southern Plains with a series of embedded vorts
continuing to flow on its southern periphery. Wouldn`t be
surprised to see another 1-4" of rain across the area (highest
I-10 northward) before all is said and done. And with the deep
moisture and potential mesoscale boundaries/convergent zones you`d
keep an eye out for potential localized higher totals. Grounds are
already saturated from last weeks rain, and additional heavy rain
falling in a shorter time period will be prone to quickly runoff.
So, it`s a forecast worth watching this weekend.

With the passage of the mid-upper trof to the east, we`ll see
some drier condition on Tue with some subtle ridging. That,
however, won`t last too long. Ridging will slide to the east and
we again transition to a messier wsw flow aloft as the next
western trof takes shape, a continued onshore llvl flow off the
Gulf, and eventually a slow moving front sagging closer to the
area later next week. 47

&&

.AVIATION...
(18Z TAF Issuance)
Issued at 109 PM CDT Thu May 9 2024

A mix of IFR to MVFR cigs/vis currently occuring across SE Texas
sites. Visibility restrictions due to smoke transport from Mexico
will continue for much of the region through at least late
afternoon or early evening and is expected to gradually disperse
early tonight. Even with a strong cap in place, a weak shortwave
passing through has helped initiate iso SH/TS activity over the
area and is expected to continue during the next few hours. Later
this evening into tonight, storms developing along a cold front to
our N-NE is expected to move into the Brazos Valley and Piney
Woods region. Based on the environmental conditions, some of these
storms could be strong to severe and will be capable of producing
large hail and damaging winds. Iso tornadoes cannot be ruled out
either. The sites that have the greatest risk for severe storms
are CLL/UTS/CXO, but may even extend into SGR/IAH although they
are expected to dissipate as they move S-SE and approach the I-10
corridor. The cold front is expected to quickly move across SE
Texas tonight, thus, a northerly wind shift along with an increase
in wind speeds can be expected during the overnight to early
morning hours. That being said, N-NE winds will remain at 10-15
KTS for much of the day Fri. Skies are expected to lift and
scatter out near sunrise.

24

&&

.MARINE...
Issued at 354 PM CDT Thu May 9 2024

A cold front will make its way into the upper Texas coastal waters
late tonight and early Friday morning. There may be some isolated
showers and thunderstorms ahead of it, but the vast majority of
storms will dissipate further inland before reaching the waters.
Areas of haze/fog should improve after the wind shift. North and
northeast winds in the wake of the front will swing back to the
southeast by early Sunday as the front moves back inland as a warm
front. Periods of showers and thunderstorms can be expected
Sunday and Monday. 47

&&

.HYDROLOGY...
Issued at 354 PM CDT Thu May 9 2024

Although there have been decreases in the water levels along the
rivers, some will remain swollen for days (possibly weeks). Do NOT
go around barricades and stay out of the floodwaters. Do NOT return
to homes until officials deem that it is safe.

River flooding continues for parts of Southeast Texas, particularly
along portions of the Trinity river. The following river points are
at Moderate or Major flood stage as of Thursday afternoon:

- Trinity River (Liberty): Major Flood Stage
- Trinity River (Moss Bluff): Major Flood Stage
- Trinity River (Riverside): Moderate Flood Stage
- Trinity River (Goodrich): Moderate Flood Stage

Remember to heed any instructions from your local officials and to
never travel through flooded areas or roadways. TURN AROUND, DON`T
DROWN. Please monitor updated forecasts via the NWS AHPS website
and/or the new NWS NWPS webpage (https://water.noaa.gov/) as the
river flood threat continues.

Also of note is that the downstream runoff from the previous
rainfall will cause continued rises along the Brazos River through
the end of the week.

24

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)  70  83  65  82 /  40   0  10  10
Houston (IAH)  72  88  68  84 /  30  10  10  20
Galveston (GLS)  75  84  73  80 /  10   0   0  20

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...Small Craft Should Exercise Caution through late tonight for
     GMZ370-375.

&&

$$