Area Forecast Discussion
Issued by NWS Houston/Galveston, TX

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FXUS64 KHGX 242009
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
309 PM CDT Sun Mar 24 2024

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

.SHORT TERM...
(This evening through Monday Night)
Issued at 239 PM CDT Sun Mar 24 2024

Continued lee cyclogenesis to our NW has produced a relatively
tight surface pressure gradient this afternoon, resulting in
gusty winds area-wide as the gradual eastward jog of surface high
pressure over the SE CONUS has veered winds further to the south.
Observations as of 2 PM CDT have shown many locations with gusts
in excess of 30 mph, a trend that will continue into the evening
and overnight hours prior to the approach of a complex of
thunderstorms on Monday morning in what will likely be our most
active period of weather for the foreseeable future.

As the surface low, along with an associated dry line and
vigorous midlevel trough, continues to advance to the east, high
resolution models indicate convective initiation to the east of
the D/FW metroplex after sunset. Recent HREF suite continues to
show the organization of convection into an MCS in the proceeding
hours, with this complex advancing towards SE TX over the course
of the overnight period. Locally, the overnight hours will be
characterized by widespread dense cloud cover and persistent WAA,
which should generally keep lows in the upper 50s across the
northern zones and the mid to upper 60s elsewhere. While effective
shear values will be quite strong (50-60+ knots) ahead of the
approaching storm complex, SB instability looks to remain below
500 J/kg. As such, SPC continues to maintain a Marginal Risk for
severe weather area-wide with the main threat continuing to be the
potential for some strong wind gusts in any stronger embedded
cells.

Timing on showers and storms remains on track with little
difference apparent between the two most recent HREF runs. Storms
will approach the Brazos Valley just before sunrise, pushing to
the southeast over the course of the morning and exiting the area
to the easy by the early afternoon. A few lingering showers into
the mid-afternoon can`t totally be ruled out for locations mostly
to the east of I-45.

Behind the departing storm complex, a cold front associated with
the surface low will move into the area. This will result in a
northerly wind shift along with an abrupt entrance of cooler and
drier air with clearing skies. Overnight temperatures, aided by
clearer skies and persistent CAA, will dip into the upper 40s/low
50s for most locations.

Cady


&&

.LONG TERM...
(Tuesday through next Saturday)
Issued at 239 PM CDT Sun Mar 24 2024

We pick things up on Tuesday with drier air in place following the
passage of Monday`s cold front. By sunrise on Tuesday morning, PW
values will be around 0.4" (10th percentile: ~0.47") with chilly
temperatures to start the day. Cooler 850mb temperatures remaining
overhead will allow for temperatures to top out in the mid 60s to
low 70s on Tuesday. Temperatures on Tuesday night will be a tad bit
cooler than on Monday night as we dip down into the low to mid 40s
in the Brazos Valley, low 50s around the Houston metro area, and mid
50s along the coast.

Wednesday will be similar to Tuesday temperature-wise, but not
synoptic-wise. A vort max on the tailend of an upper level trough
pushes through on Wednesday and will at least make an attempt to tap
into slightly elevated moisture...but even then PW values remain
around 0.8-0.9" at most. Not much moisture to work with, but on top
of that forecast models continue to indicate dry air extending ~1-2
km AGL. So, even with the added mid level lift (including a 25-30 kt
LLJ over the Brazos Valley), most if not all of the rain from any
elevated showers would evaporate before reaching the surface. That
being said, while virga is the most likely outcome, I did leave in
10% PoPs in the event some rogue sprinkles reach the surface...and
that`s most likely to occur in the Brazos Valley. There is a 99.9%
chance of an increase in mid level cloud cover though!

Once the upper level trough ejects to the east on Thursday, ridging
aloft builds in behind it leading to an increasing temperature trend
going towards the end of the week. At the surface, onshore flow
returns by late Thursday leading to a gradual increase in
moisture/humidity going into the weekend. By Friday, we`ll be
flirting with the 80°F mark and daytime highs firmly in the 80s over
the weekend. For those that want an early preview of the Easter
forecast, it definitely looks rather warm. 850mb temperature
percentiles (NAEFS/GEFS) approach an exceed the 90th percentile
going into late Saturday and continuing into Sunday. This is due to
southwesterly flow aloft being induced as upper level low riding
along the Pacific coast shifts southward and becomes embedded in an
eastward drifting upper level trough. It`s too early to dive any
deeper into the details, but just know that signs are pointing
towards a warmer than normal Easter Sunday!

Batiste

&&

.AVIATION...
(18Z TAF Issuance)
Issued at 1252 PM CDT Sun Mar 24 2024

Continued gusty southeast winds are expected through the overnight
period ahead of the approach of our next storm system early
tomorrow. Sustained winds remain around 15 to 20 knots, with gusts
of 25 to 30 knots expected to prevail well into the night. Wind
direction will continue to veer slightly more to the south during
this time. A period of active weather tomorrow is expected as a
complex of showers and thunderstorms moves into the area ahead of
a cold front. This will be accompanied by periods of low end MVFR
to IFR cigs and intermittent low visibilities. Storms should
generally move through the area from NW to SE, reaching CLL around
10-11Z, IAH/HOU by 12-13Z, and the coast by 14-15Z. Storm
coverage and intensity should generally remain higher to our east,
but a few stronger storms could produce some strong wind gusts at
times. Rainfall coverage will be a bit more sparse at the coastal
terminals. Storms depart the area tomorrow afternoon with clearer
skies developing soon after along with northwest winds.

Cady

&&

.MARINE...
Issued at 239 PM CDT Sun Mar 24 2024

A tightening pressure gradient ahead of an approaching weather
system has lead to an increase in southeasterly winds. A Small Craft
Advisory is currently in effect for the offshore waters and will go
into effect for the nearshore waters and the Bays later this
afternoon. The advisories are currently in effect through Monday
afternoon, but may need to be extended into Tuesday for the offshore
waters due to elevated seas persisting. Wind speeds will reach their
peak on this afternoon into tonight with some gusts approaching gale
force at times. The elevated southeasterly winds will increase the
risk of rip currents along Gulf-facing beaches on Sunday and Monday,
and brings about the potential for minor coastal flooding during
high tide on early Monday morning.

As previously mentioned, seas will continue to increase up towards
the 8-10 ft range tonight into Monday due to the elevated
southeasterly winds. Some showers and thunderstorms will be possible
on Monday morning/early afternoon as a cold front pushes offshore.
Light northerly winds will prevail in the wake of the front into
Tuesday as seas gradually subside. By Wednesday, winds will
transition to northeasterly, then become southeasterly by late
Thursday.

Batiste

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)  60  76  45  66 /  50  70   0   0
Houston (IAH)  67  78  53  72 /  30  70   0   0
Galveston (GLS)  67  74  59  71 /  10  50   0   0

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...High Rip Current Risk through Monday evening for TXZ436>439.

GM...Small Craft Should Exercise Caution until 4 PM CDT this
     afternoon for GMZ330-335-350-355.

     Small Craft Advisory until 1 PM CDT Monday for GMZ330-335-350-
     355.

     Small Craft Advisory until 4 PM CDT Monday for GMZ370-375.

&&

$$

SHORT TERM...Cady
LONG TERM....Batiste
AVIATION...Cady
MARINE...Batiste


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