492
FXUS64 KHGX 041117
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
617 AM CDT Sat May 4 2024

...New AVIATION...

.SHORT TERM...
(Today through Sunday Night)
Issued at 431 AM CDT Sat May 4 2024

Weak impulses aloft with PWs in excess of 1.5" will bring isolated
showers and thunderstorms across portions of SE Texas throughout
most of today. Generally, showers and storms look to be weaker in
nature, though we can`t completely rule out the potential for the
occasional storm with a tad more potency. With rainfall being less
widespread compared to previous days, highs across the region should
climb into the 80s.

A shortwave trough will enter Texas later this evening, bringing
with it our our next "wave" of stronger storms and heavy rainfall.
These storms should begin to fire up over Central Texas later
tonight, tracking E/SE with the trough and entering our Northwestern
counties near/in the Brazos Valley around midnight.
Shower/thunderstorm coverage will later spread SE on Sunday. This
environment will contain a weak LLJ, a deep warm cloud layer,
saturated conditions in the mid/lower levels with PWs of 1.75-2.00
inches; indicating high precipitation efficiency and the potentially
for locally heavy rainfall with these storms. CAM guidance generally
places the highest rainfall totals further north across portions of
the Brazos Valley/Piney Woods area, though the 00z & 06z runs of the
HRRR suggest the possibility of heavier rainfall developing further
south as well, including portions of the Houston metro area. CREST
still shows swaths of soil moisture in excess of 40% north of I-10
and east of College Station. Meanwhile, RFC 1hr FFG remains around 2-
3" for most areas outside of our southwestern counties (North of I-
10 as well as east of I-45). A few locations even show 1hr FFG below
2" as well.

WPC has SE Texas under a Slight (level 2/4) to Marginal (level 1/4)
Risk of Excessive Rainfall during this overnight period into Sunday.
A Flood Watch remains in effect for most areas along and north of
the I-10 corridor, including the Chambers county and the Houston
Metro area, until 1 PM on Sunday. An additional 1-3" of rainfall is
expected with isolated higher amounts up to 5" possible in the watch
area. Locally heavy rainfall in these storms may result in flash
flooding, along with further exasperating ongoing flooding across SE
Texas. While flooding remains the primary concern, sufficient
instability and shear could allow for a few strong/severe storms to
develop as well with the shortwave. WPC has ports of SE Texas under
a Marginal (level 1/5) Risk of severe weather this weekend, with the
strongest of these storms capable of producing damaging winds and
hail.

Storm activity looks to decrease in the evening hours of Sunday as
the aforementioned shortwave exists to the east. However, weak
impulses aloft may still bring isolated rain chances through late
Sunday night.

03

&&

.LONG TERM...
(Monday through Friday)
Issued at 431 AM CDT Sat May 4 2024

From a significant wet period, we will transition to a hot weather
pattern during the long term. Weak upper-level ridge will build
across the middle/lower MS Valley while a strong upper-level low
develops over the northern Rockies/High Plains. This pattern will
bring a quasi-zonal flow aloft, that combined with southerly flow
at the surface will bring warmer and more humid conditions across
the region. This scenario looks to persist through the entire
week. In fact, deterministic solutions keep suggesting 850mb
temperatures climbing into the 20 to 25 degC Tuesday - Thursday.
Ensemble solutions also keep suggesting this hot pattern, with
values within the 99th to Max percentile of climatology per NAEFS
and GEFS. With that being said, leaned towards a blend between
NBM/NBM75th for MaxT through the week. Overall, look for highs
mainly into the low to mid 90s. At the moment, Wednesday and
Thursday look to be the hottest days with widespread readings into
the low to mid 90s.

Precipitation-wise, a relatively dry week is expected with only
isolated to scattered activity possible during the day with the
combination of diurnal heating and passing subtle shortwaves aloft
Monday and after mid-week. Any of this activity is more likely to
occur across our far northern counties; therefore, kept slight
chances in the forecast over these counties. The next rain/storm
chances look to arrive after Friday ahead and along of a weak
frontal boundary.

JM

&&

.AVIATION...
(12Z TAF Issuance)
Issued at 604 AM CDT Sat May 4 2024

CIGS (ranging from MVFR to LIFR) should gradually lift/clear this
morning. Isolated showers could develop at times during the day,
but coverage remains too low to warrant mention in the TAFs.
Expect MVFR CIGS to fill back in later tonight, potentially
dropping to IFR levels during the early morning hours of Sunday as
another wave of showers/thunderstorms moves through SE Texas.
These storms could bring heavy rain, and potentially some isolated
strong to severe storms.

03

&&

.MARINE...
Issued at 431 AM CDT Sat May 4 2024

Moderate to occasionally strong onshore winds and seas between 3 to
6 ft will prevail this weekend and into next week. Small Craft
Should Exercise Caution conditions will continue today due to
winds and seas occasionally reaching 7 to 8 ft offshore. Scattered
to numerous thunderstorms can be expected later tonight into
Sunday as a disturbance moves through. Erratic wind gusts and
higher seas can be expected near any strong/severe storms. Dry
and hot weather with moderate onshore winds and seas generally up
to 5 ft can be expected through the week.

Beach conditions...there is a high rip current risk for all Gulf
facing beaches through late this evening.

JM

&&

.HYDROLOGY...
Issued at 431 AM CDT Sat May 4 2024

There is ongoing river flooding over parts of Southeast Texas,
particularly along portions of the Trinity and San Jacinto rivers
and a few sites along Brazos River. The following river points are
at, or forecast to go to Major flood stage:

- Trinity River (Riverside): Major Flood Stage
- Trinity River (Romayor): Major Flood Stage
- Trinity River (Liberty): Major Flood Stage
- Trinity River (Goodrich): Major Flood Stage
- Trinity River (Moss Bluff): Moderate forecast to go to Major
- West Fork San Jacinto (Conroe): Major Flood Stage
- West Fork San Jacinto (Humble): Major Flood Stage
- San Jacinto (Sheldon): Major Flood Stage
- East Fork San Jacinto (New Caney): Major Flood Stage
- Navasota River (Normangee): Major Flood Stage
- Menard Creek (Rye): Major Flood Stage

Remember to heed any instructions from your local officials and to
never travel through flooded areas or roadways. 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.

JM

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)  84  70  81  70 /  20  90  60  20
Houston (IAH)  84  73  82  71 /  20  60  50  20
Galveston (GLS)  80  74  80  73 /  20  30  30  20

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...Flood Watch through Sunday afternoon for TXZ163-164-176>179-
     195>200-212>214-300-313.

     High Rip Current Risk through this evening for TXZ436>439.

GM...Small Craft Should Exercise Caution until 1 PM CDT this
     afternoon for GMZ350-355-370-375.

&&

$$

SHORT TERM...03
LONG TERM....JM
AVIATION...03
MARINE...JM