928
FXUS64 KHGX 272328
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
628 PM CDT Sat Apr 27 2024

...New AVIATION...

.SHORT TERM...
(This evening through Sunday Night)
Issued at 337 PM CDT Sat Apr 27 2024

A mid/upper level trough over the Four Corners should fill NE across
the Plains this evening. The tight gradient and 30-40 knot LLJ
should continue to bring windy conditions across SE Texas overnight.
Expect winds to be south/southeasterly around 15-25 mph with gusts
of around 25-35 mph. Therefore, a Wind Advisory will remain in
effect for most areas south of the I-10 corridor through 7 PM CDT
Tonight. For the barrier islands east of Freeport, the Wind Advisory
will remain in effect until 7 AM Sunday. Persistent onshore flow
with ample moisture and cloudy skies should keep lows for Sunday
morning in the 70s across SE Texas.

A cold front/dry line associated with the aforementioned upper level
system will approach the Brazos Valley late Sunday morning. As it
nears our area, the pressure gradient will weaken, reducing wind
speeds & gusts. Isolated storms should begin to pop up during the
afternoon ahead of this boundary. During the late afternoon/early
evening, guidance indicates a more cohesive line/cluster of
thunderstorms developing along a weaker boundary, tracking E/SE
overnight. The environment for these storms still appears to be
fairly potent. ML CAPE values during the late afternoon rise to
around 2100-2800 J/KG in areas east of I-45, in excess of 3000 J/KG
in areas to the west. LIs peak around -6 to -10 Deg C, with mid
level lapse rates ranging from 6.5-8.5 Deg C/km. ML LCL heights will
be under 1000m. Effective shear (EBWD) will range from 35-45 knots,
with 3 km SRH ranging from 100-250 m2s2. PWs remain near 1.6-1.9
inches.

Currently SPC has areas north of the I-10 corridor under a Slight
(level 2/5) Risk of severe weather on Sunday, with the remainder of
SE Texas under a Marginal (level 1/5) Risk. These storms appear to
take on more of a discrete storm-mode, capable of producing all
severe weather hazards. Damaging winds and large hail remain the
primary hazards, but an isolated tornado cannot be ruled out.

These storms will also be capable of producing locally heavy
rainfall. WPC has the northern third of our CWA under a Slight
(level 2/4) Risk of Excessive Rainfall for Sunday, with areas to the
south partially under a Marginal (level 1/4) Risk. Rainfall totals
through Monday morning are expected to range from 0.5"-2.25" with
locally higher amounts up to 4" possible with any slower-moving
storms.

The severe weather & heavy rainfall threat should decrease overnight
as the boundary pushes further south, displacing these storms
further from the upper level trough, reducing the already weak
forcing aloft. This weak/diffuse boundary should slow/stall out
around the I-10 corridor, through conditions will still be fairly
warm/humid across the region Monday Morning.

03

&&

.LONG TERM...
(Monday through next Friday)
Issued at 337 PM CDT Sat Apr 27 2024

Periods of showers and thunderstorms will remain in the forecast as
a series of disturbances/impulses/shortwaves move across the state
in a generally west to southwest flow aloft while onshore winds
remain in place. Enough instability could persist on Monday for
possible strong/severe storms (Marginal Risk on SPC`s Day 3
Convective Outlook) and locally heavy rain (Marginal Risk on WPC`s
Excessive Rainfall Outlook). For the rest of the period, could see
shower/storm development almost any day with better chances
generally across our northern counties. High temperatures will be in
the 80s and lows will be mainly in the 70s. 42

&&

.AVIATION...
(00Z TAF Issuance)
Issued at 612 PM CDT Sat Apr 27 2024

Persisting strong SSE flow at 10-20KT with some stronger gusts is
pulling in warm, moist air with dewpoints in the mid 70s
throughout the region. With some speed convergence occurring
inland, expect lower ceilings throughout the evening and
overnight as that pool of surface moisture is lifted. Showers and
thunderstorms are expected to the west of the region, but should
decay before reaching the area. There is some potential for
showers near College Station, but chances are low. Throughout the
late morning and afternoon on Saturday, ceilings should
transition upward. The probability of storms will increase into
the late afternoon as daytime heating erodes the capping that will
be present across the area earlier in the day. Instability
generated by daytime heating, in conjunction with the approaching
dryline and synoptic-scale lift from a midlevel trough indicate
the potential for some severe cells in the late afternoon and
evening.

CJ


&&

.MARINE...
Issued at 337 PM CDT Sat Apr 27 2024

Moderate to strong onshore winds (15 to 25 knots with gusts >30 knots)
and elevated seas (10 to 12 feet offshore) will continue through the
weekend. Small Craft Advisories are in effect through Sunday. Minor
coastal flooding is possible in vulnerable locations at times of high
tide. Rain chances increase on Sunday with scattered showers and thunderstorms
persisting into Monday. Winds will gradually decrease late Sunday into
Monday, with lingering high seas keeping conditions dangerous to small
craft through Sunday night. Though more moderate, onshore flow will
persist early next week. 42

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)  73  82  69  85 /  10  80  70  20
Houston (IAH)  74  84  70  85 /  10  50  60  60
Galveston (GLS)  73  80  72  80 /   0  40  40  60

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...Wind Advisory until 7 PM CDT this evening for TXZ214-226-227-
     235>238-300-313-335>338-436.

     Beach Hazards Statement through Sunday evening for TXZ436>439.

     Wind Advisory until 7 AM CDT Sunday for TXZ437>439.

GM...Small Craft Advisory until 10 AM CDT Sunday for GMZ330-335.

     Small Craft Advisory until midnight CDT Sunday night for GMZ350-
     355.

     Small Craft Advisory until 5 AM CDT Monday for GMZ370-375.

&&

$$