377
FXUS64 KHGX 031104
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
604 AM CDT Fri May 3 2024

...New AVIATION...

.SHORT TERM...
(Today through Saturday Night)
Issued at 302 AM CDT Fri May 3 2024

The current "lull" in shower/storm activity across SE Texas looks to
be coming to an end, as isolated shower/storms have begun to develop
across the region. High-resolution models indicate rain chances
increasing throughout this morning as a shortwave passes overhead,
tapping into rich PWs of 1.75-2.00" to bring more
showers/thunderstorms across the region. While the mesoscale
environment will make things messy, guidance seems to hint at two
main "clusters" of storms developing with this next wave. The first
cluster appears to develop over the southern half of our CWA,
talking on an E/NE track. While closer to the primary moisture axis,
models seem to suggest more modest rainfall rates in this cluster.
Meanwhile, the second cluster looks to develop further north over
the Brazos Valley/Piney Woods area, tacking Southeasterly. Forcing
with this system appears to be a tad more robust, located in the
vicinity of the left exit region of the upper level subtropical jet,
which also appears to coincide with a convergence zone with the
925mb LLJ during the afternoon. Some short term guidance suggests
that rainfall rates would be higher in this cluster.

Crest shows swaths of soil moisture in excess of 40% in areas north
of I-10, peaking in excess of 70% over portions of Walker & Trinity
counties. RFC 1hr FFG for much of this same area is around 1.5-2.5",
though lower values of under 0.5" encompass portions of
Liberty/Harris counties. Overall the heavy rainfall threat will
still encompass most of SE Texas, with a Flood Watch remaining in
effect for most areas North of I-10 until 7 PM Tonight. The threat
of heavy rainfall remains greatest early this morning, where WPC
still has SE Texas under a Moderate (level 3/4) to Slight (level
2/4) risk of Excessive Rainfall. The threat of excessive rainfall
subsequently decreases during the late morning/early afternoon to a
Slight (level 2/4) to Marginal (level 1/4) Risk. Flood Warnings and
River Flood warnings are ongoing across the region, and any
additional heavy rainfall may further exasperate hydrological
problems. Be careful while driving and avoid any flooded roadways.

There looks to be a short reprieve from rainfall later today, with
showers/storms tapering off this evening/tonight. Guidance still
suggests the possibility of showers/storms developing again early
Saturday morning, though the risk of excessive rainfall remains
Marginal (level 1/4) during this period, mainly in our
North/Northwestern Zones. Ample moisture and lifting from
disturbances aloft will enable rain chances and flooding concerns to
persist into the long term forecast.

03

&&

.LONG TERM...
(Sunday through Thursday)
Issued at 302 AM CDT Fri May 3 2024

One more day of scattered showers and thunderstorms is expected on
Sunday as a stronger shortwave trough moves north of the area. At
the surface, a weak boundary (warm front) will lift northward into
SE TX during the day. Increasing theta-e advection, sufficient
moisture and instability will lead to increasing precipitation
chances during the day. Unfortunately, the bulk of this activity
looks to occur again north of I-10; however, rainfall totals are
progged to remain around a half inch or less.

The main weather story in the medium range evolves in the increased
heat risk. A relatively dry weather is expected through most of the
week. However, a quasi-zonal flow aloft, and south to southwest flow
at the surface will lead to above normal temperatures. 850mb
temperatures will warm into the upper teens to mid 20s degC range
during the week, suggesting highs in the 90s. Based on latest models
solutions, Thursday is shaping up to be one of the hottest days with
highs generally into the mid 90s. These values are within the 99th
percentile of climatology per NAEFS and GEFS. These readings are
progged to be 5 to 10+ degrees above normal for this time of year.

JM

&&

.AVIATION...
(12Z TAF Issuance)
Issued at 552 AM CDT Fri May 3 2024

MVFR to IFR CIGS will slowly begin to lift this morning, climbing
back to VFR levels this afternoon. Scattered showers &
thunderstorms will taper off this evening, with more MVFR/IFR CIGS
developing overnight into Saturday. Southeasterly winds prevail
throughout the TAF period.

03

&&

.MARINE...
Issued at 302 AM CDT Fri May 3 2024

Moderate southeast winds, seas between 3 to 6 ft and isolated to
scattered showers and thunderstorms are expected today and tonight.
Gusts from 15 to 20 knots will be possible at times, stronger around
any thunderstorms. Therefore, Small Craft Should Exercise Caution
Conditions will continua today for all bays and Gulf waters.
Moderate to occasionally strong onshore winds and seas from 3 to 6
ft should remain through the weekend and into the upcoming week.
Seas can reach advisory levels (around 7 ft) at times well offshore.
Rain and storm chances decrease during the weekend, bringing benign
marine conditions into next week.

JM

&&

.HYDROLOGY...
Issued at 302 AM CDT Fri May 3 2024

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

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

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)  83  71  84  71 /  50  10  20  30
Houston (IAH)  83  72  84  73 /  50  10  10  20
Galveston (GLS)  80  74  80  74 /  50  10   0  10

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...Flood Watch through this evening for TXZ163-164-176>179-195>200-
     212-213-300-313.

GM...Small Craft Should Exercise Caution through this evening for
     GMZ330-335-350-355-370-375.

&&

$$

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