244
FXUS64 KHGX 122343
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
643 PM CDT Sun May 12 2024

...New AVIATION...

.SHORT TERM...
(This evening through Monday Night)
Issued at 346 PM CDT Sun May 12 2024

The next round of showers and storms has begun in SE Texas, and like
with the previous few heavy rain events, the focus on the heavy
rainfall has been within the Pineywoods region. Today`s rainfall is
thanks to a passing upper-level shortwave passing through along with
a warm front moving up through SE Texas. Also monitoring the
potential for isolated strong to severe storms. Storms this morning
did produce hail, up to 1.25", and hail will continue to be the main
severe weather hazard through the evening. However, there is some
potential for brief tornadogenesis into this evening as the storms
become more surface based after the warm front pushes through.
Because of this, a tornado watch is in effect until 7pm for the I-10
corridor starting in Waller County then eastwards and up to Polk
County.

As of 3pm, rainfall amounts have generally been up to 1" south of
Lake Livingston, and then between 1 and 3" northwards. There will be
continued showers and storms through the afternoon with an increase
in coverage and intensity this evening as the warm front moves into
the Pineywoods region. CAM guidance shows that the storms this
evening will have the potential to drop an additional 1-3" with
isolated higher amounts if training storms develop. Activity will be
winding down between midnight and 3am, but another round of showers
and storms is expected on Monday as another upper-level shortwave
slides through.

The severe weather potential is higher tomorrow than it is today
thanks to the warm front ushering in a high CAPE, strong shear
environment. Storms that develop will have the potential to become
strong to severe producing large hail, gusty winds, and potentially
a brief tornado. SPC continues the Slight Risk (level 2/5) across
the entire region tomorrow due to these risks. The storms will start
in the mid to late morning in the B/CS area, progressing eastwards
through SE Texas during the afternoon, and eventually exiting to the
east in the evening.

The Flood Watch remains in effect through Monday morning for Brazos,
Madison, Grimes, Walker, Montgomery, San Jacinto, Houston, Trinity,
Polk, and northern Liberty counties. Within the watch area,
generally up to 2 to 4" of rainfall can be expected, although
isolated amounts up to 6" is possible if training storms develop
through tonight. Areas along and south of I-10 will see more hit-or-
miss showers and thunderstorms into tonight producing up to 0.5-2".
WPC maintains the Moderate Risk (level 3/4) for Excessive Rainfall
generally within the Watch area through tonight with a Slight Risk
(level 2/4) down through I-10 corridor, and a Marginal Risk (level
1/4) down along the coast.

An additional 1-3" with isolated higher amounts possible is expected
on Monday as the line of storms moves through. Unlike the past few
storm systems, areas along and south of I-10 will have the better
chances of the higher rain totals. SPC has areas along and east of I-
45 in a Slight Risk for Excessive Rainfall tomorrow with a Marginal
Risk elsewhere. We will keep the Flood Watch as is for this update,
but it may be extended in time through Monday evening if guidance
trends wetter for the Pineywoods region.

Temperatures tonight into Monday afternoon will be well above
average. Overnight lows will be mid to upper 70s along and south of
I-10, and low to mid 70s northwards. High temperatures tomorrow will
be in the mid to upper 80s across the region with heat indicies in
the low to mid 90s. Rainfall will cool the air for tomorrow night
bringing low temperatures down into the mid to upper 60s for most of
the region and mid 70s along the coast.

Fowler

&&

.LONG TERM...
(Tuesday through next Saturday)
Issued at 346 PM CDT Sun May 12 2024

We are expecting a respite in showers and storms on Tuesday as
surface high pressure builds, quasi zonal flow sets up overhead,
and air drier moves across the region behind the cold front.
Expect sunny to partly cloudy skies and north northeast winds on
Tuesday with highs in the mid to upper 80s. The lows Tuesday night
into early Wednesday morning will cool a little more and range
between the low to mid 60s along the Brazos Valley and Piney Woods
region, the mid to upper 60s for the rest of the inland areas,
and in the low 70s along the coasts.

During the day on Wednesday, generally tranquil conditions will
prevail as the surface high pressure shifts to the east southeast
into LA. As it does so, moisture from southern TX and northwestern
Gulf of Mexico will begin to move in. PWs will be rising starting
over the Matagorda region Wednesday afternoon and expand quickly
northeastward into the rest of the region during the night hours.
There may be some weakness aloft for that period and could result
in showers during the evening and night hours. That being said,
GFS is showing some vort maxes moving over areas north of I-10
during the overnight periods as well, which could help increase
shower activity over that region. Isolated thunderstorms are also
possible.

By sunrise on Thursday, moisture convergence is expected with PWs
possibly as reaching 2.0 inches over much of Southeast TX. Upper
level disturbances will be passing through during the day and
instability will increase. We will also have the added lift ahead
of another cold front that is to move south southeastward from
Central TX. Thus, we can expect scattered to numerous showers and
thunderstorms on Thursday. Areas north of I-10 may once again be
under the heaviest side of the weather, with the possibility of
some strong storms as well heave periods of heavy rainfall.
Knowing what additional impacts we get on Thursday is still a
little to early to know, but given we are expecting heavy rainfall
today and Monday along with the possibility of saturated soils
and elevated river levels, any additional heavy rainfall could
lead to flash flooding and further rises along the small creeks,
bayous, and river. Again, this is very dependent on how much
rainfall we obtain today into Monday and where the higher rainfall
occurs. WPC`s Excessive Rainfall Outlook for Thursday has a
Slight Risk (threat level 2 of 4) for most of Southeast TX except
the southwestern counties closer towards the Matagorda Bay region.

The cold front is expected to push across the region sometime
late Thursday night into Friday morning. Some models hint at the
front stalling over the region unfortunately, which may keep some
chance for rain Friday into the weekend. Thus, if the front does
push into the Gulf waters, then chances of rain will be low;
however, if it does stall inland, then we may have slightly higher
PoPs at times Friday into the weekend. For now, kept periods of
low PoPs (20% or less).

For temperatures, highs in the upper 80s to low 90s can be
expected each day except Thursday where highs could be in the low
to mid 80s. For lows, they will be in the 60s Tuesday night, but
increase into the mid 60s to low 70s midweek into the end of the
work week.

Cotto

&&

.AVIATION...
(00Z TAF Issuance)
Issued at 637 PM CDT Sun May 12 2024

Isolated showers continue to work their way through SE Texas this
evening. Activity is generally along and north of I-10 corridor
and will begin to wane around midight. MVFR/IFR conditions
expected overnight with CIGs looming around 700-1500 feet. Patchy
fog may develop and bring VSBYs to MVFR levels at times. Winds
will be southeasterly to south-southeasterly through tomorrow.
More showers and thunderstorms are expected tomorrow afternoon
with the potential for some storms to become strong to severe.

&&

.MARINE...
Issued at 346 PM CDT Sun May 12 2024

Moderate to occasionally strong east winds with seas of 3 to 6
feet will continue through this evening and possibly into tonight.
Small craft should continue to proceed with caution along the bays
and Gulf waters. Periods of showers and storms will continue,
increasing on Monday. A cold front will push into the waters late
Monday night into Tuesday morning, briefly bringing offshore winds
through Tuesday afternoon. Moderate onshore flow returns Tuesday
evening. Chance for showers and storms will rise again Wednesday
night into Thursday as another disturbance moves across the region
and another cold front moves through.

Cotto

&&

.HYDROLOGY...
Issued at 346 PM CDT Sun May 12 2024

A Flood Watch remains in effect through Monday morning for
portions of the Piney Woods and the Brazos Valley. So far today,
most of the rainfall has fell in parts of San Jacinto, Polk, and
Houston Counties. Soils in this area are already fairly saturated
from last week`s heavy rain events. This means that rainfall will
become runoff quickly leading to additional responses along area
rivers/creeks/bayous. Flash flooding is also a possibility in
these locations. Expecting 1-3" of rainfall with isolated higher
amounts today, and an additional 1-3" of rainfall with isolated
higher amounts on Monday.

Minor to major river flooding continues for parts of Southeast
Texas, particularly along portions of the Trinity and Brazos
rivers. The following river points are either currently in flood
stage or are forecast to reach flood stage (as of Sunday
afternoon):

- Trinity River (Liberty): Major Flood Stage
- Trinity River (Riverside): Moderate Flood Stage
- Trinity River (Moss Bluff): Moderate Flood Stage
- Brazos River (West Columbia): Moderate Flood Stage
- Menard Creek (Rye): Moderate Flood Stage (forecast)
- Brazos River (Rosharon): Moderate Flood Stage (forecast)
- Trinity River (Crockett): Minor Flood Stage
- Trinity River (Goodrich): Minor Flood Stage
- Brazos River (Richmond): Minor Flood Stage
- Brazos River (Sugar Land): Minor Flood Stage
- Long King Creek (Livingston): Minor Flood Stage (forecast)
- Navasota River (Normangee): Minor Flood Stage (forecast)

Remember to heed any instructions from your local officials and to
never travel through ANY 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.

Batiste

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)  72  85  65  87 /  60  50  20   0
Houston (IAH)  74  87  68  89 /  40  70  40   0
Galveston (GLS)  77  84  73  86 /  30  60  40   0

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...Flood Watch through Monday morning for TXZ163-164-176>179-196-
     198>200.

     High Rip Current Risk until midnight CDT tonight for TXZ436>439.

GM...Small Craft Should Exercise Caution through Monday afternoon for
     GMZ330-350-370-375.

     Small Craft Should Exercise Caution until midnight CDT tonight
     for GMZ335-355.

&&

$$

SHORT TERM...Fowler
LONG TERM....24
AVIATION...Adams
MARINE...24