Houston, Texas 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

322
FXUS64 KHGX 180949
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
349 AM CST Sat Jan 18 2025

...New SYNOPSIS...

.SYNOPSIS...
Issued at 334 AM CST Sat Jan 18 2025


       ***Cold Weather Advisory Tonight - Sunday Morning***

Temperatures will fall into the mid-20s to mid-30s tonight.
Coupled with gusty north winds, wind chill values are expected to
be in the 15 to 25 degree range by Sunday morning. Bundle up if
spending time outdoors. Bring the pets inside. Cover or bring
inside sensitive plants.


       ***Winter Storm Likely Monday Night - Tuesday***

Key Points:

 1) Frozen precipitation is likely over much of southeast Texas.


 2) Trends favor snow north of I-10 with a wintry mix farther
    south.

 3) Exact snowfall and ice amounts still uncertain.

A winter storm remains likely during the Monday night to Tuesday
afternoon time frame. The set up for this storm is quite complex
and the system remains too far into the future to be within range
of the higher resolution models. Therefore, uncertainy remains
relatively high regarding accumulation of snow and ice. But the
potential is there for areas of heavy precipitation.

&&

.SHORT TERM...
(Today through Sunday Night)
Issued at 135 AM CST Sat Jan 18 2025

Every day I write this short term discussion, I get a little bit
closer to writing about the weather that most people reading this
product care about! Tonight, I`m even getting to start to dip into
the initial portions of actual winter stuff! It`s not the stuff
y`all are really caring about, but it is what`s going to get us to
that part, so let`s dive in.

Low pressure is sitting over Broken Bow, Oklahoma (shoutout to
college friend from there!) dragging a cold across roughly the
northern third of Texas. That front should reach our northern border
in the pre-dawn hours. Until then, we can expect relative warmth,
with temperatures hanging out around or a little below average
*high* temps for mid-January. These temps are being held up by
higher dewpoints, which does give us potential for some patchy fog.
Fortunately, winds are a little on the high side for radiation fog,
and from a poor southwesterly fetch for sea fog, so visibility
reductions will be minimized from any patches that do crop up.

As mentioned above, the front should make its way in to places like
Caldwell, B/CS, Madisonville, Crockett, and the like shortly before
dawn, and spend much of the morning crossing Southeast Texas. I`m
anticipating it to reach the Houston metro in the 7-9 am stretch,
and push off the coast an hour or two after that.
While not exceptionally strong, we should see northwesterly to
northerly winds crank up through the day, tonight, and even a good
chunk of Sunday before beginning to settle down. These winds will
force in a colder, drier airmass that will begin our glide into a
Texas Winter Wonderland! (you may read that as genuine or sarcastic
as to match your own personal preference) It will take some time,
though - we`re not really looking at a Blue Norther situation in
this event as we are a gradual stair-step down with a series of
reinforcing colder airmasses.

So here are the stairs we look to be stepping on this weekend:
morning lows today range from the lower 40s way up north where the
front sneaks in before sunrise to the upper 50s on the Gulf coast.
The new cold air wipes out much of our daytime warming, with highs
in the lower 50s to lower 60s. We`ll step it on down a little more
tonight, with widespread lows in the 30s across most of the area,
and sliding into the upper 20s north of the Houston metro.
Assuming the winds keep up as anticipated, we`ve got some cold wind
chills anticipated, and have opted to go with a cold weather
advisory for much of the area to handle those wind chills. We`re
nowhere near the wind chills of my Wisconsin youth, but by Southeast
Texas standards, these are going to be some meaningfully cold
apparent temperatures. Layer up, bundle up...or just stay inside
Sunday morning, whatever you need to do to head off the sting of
those cold winds!

Full sun tomorrow helps increase the diurnal temperature range, so
we`ll actually warm up more tomorrow than we will today...it`s just
that we`re starting from such a colder place that it doesn`t matter,
it`s still noticeably colder across the area. Look for highs in the
40s area-wide. Crockett up in Houston County may struggle to even
hit that 40 degree mark!

Finally, we get even colder tomorrow night. With another stair step
down, we are now in the realm of hard freezes north of the Houston
metro, in the rural areas off to the west, and even creeping into
the northern suburbs as well. I`d like to give it a little more time
to refine just how far south a hard freeze will be likely before
putting out a freeze watch, but one will be needed for at least part
of our area before too long. Another thing we`ll have to look into
is the need for an extreme cold watch. Taken literally, our forecast
stops just shy of the need for that tomorrow night. However, it is
very close, and if we find that this incoming cold airmass is more
aggressive, we would need to more strongly consider this potential.

We`ve now reached the end of the short term...and while not the
highlight of the forecast, we`re already seeing that we`re not too
far off from some unseasonably cold temperatures, and conditions
that you`ll need to start making some preparations for to avoid a
bad time when temperatures are at their lowest.

&&

.LONG TERM...
(Monday through Friday)
Issued at 135 AM CST Sat Jan 18 2025

A robust amplifying mid/upper trough will swing through SW CONUS
and into the Lone Star State on Monday into Tuesday. Meanwhile,
strong surface high pressure (~1040-1045MB) will build southward,
enhancing CAA over south-central CONUS. A resulting baroclinic
zone is expected to develop offshore between the southward surging
arctic air and the tropical air over the Gulf of Mexico.
Increasing synoptic ascent coupled with a steepening baroclinic
zone should favor the development of low pressure offshore. Both
the low and the through will help to advect moisture northward
into southeast Texas as arctic air entrenches itself over the
region. The combination should result in a winter storm, with some
potential for heavy snow and ice. Confidence in a winter storm is
high. But the details remain merky. So let`s dive into it!

Monday is expected to feature increasing clouds from south to
north. Expect sub-freezing temperatures to start the day with
highs reaching to around 40 degrees. With enhanced CAA and
increasing clouds, it wouldn`t surprise me if those highs were
closer to 35 degrees. This will be somewhat dependent on the
timing of the approaching overcast. The chance of precipitation
increases by Monday evening. But the bulk of the system is
expected to occur after midnight through Tuesday afternoon.

In terms of the general global deterministic/ensemble consensus,
the vertical temperature profile looks to be favorable for snow
north of I-10, while areas south of I-10 may experience more of a
mixture of precipitation types. There is potential for heavy
banding of precipitation, opening the door to potential heavy
snowfall accumulations. But the uncertainty between how much snow
vs sleet vs freezing rain vs rain remains high in this update. You
may ask, why does it remain high? Isn`t there pretty decent model
consensus at this point?

Technically, there is `ok` consensus among the data. But what is
the data we are talking about? The vast majority of the available
guidance comes from the globel models since the storm is not
within range of most of the higher resolution guidance. You may
remember the cold heavy rains and gusty winds we experienced on
Thursday January 9th. Global models did an ok job resolving the
system. But it wasn`t until we had most of the HREF guidance
(within 48 hours of the storm) before model data fully captured
the strength and track of the low. The system is officially within
range of the 12KM NAM. Both the NAM and the GFS are hinting that
the system may feature more of a sleet/freezing rain mix across
the southern half of the CWA than much of the rest of the snowier
guidance. And given the favorable environment for a potentially
stronger low over the Gulf along with uncertainties in the track
of the low, I`d say there remains more p-type uncertainty than the
consistently snowy ECMWF suggests. And even in a snowier
temperature profile, uncertainties regarding the location of
banding along with the complex microphysics involved in compaction
and melting make forecasting accumulations difficult.

For now, we`re opting to go with mostly snow with a dash of sleet
for areas north of I-10. Forecast snow accumulations north of I-10 are
generally 2-4 inches with locally higher totals. Considering the
possibility of heavy banding of precip, we could not rule out
locally much heavier totals. Our precip forecast has more sleet
and freezing rain in the mix south of I-10. Therefore, the
expected snowfall accumulations generally taper as you head to the
coast. The best chance of freezing rain is south of I-10 with a
glaze of ice possible. But please do not attached yourself to
these snow/ice totals. With all the moving parts and the lack of
high resolution data, these values are almost certain to change.

It`s worth mentioning that most of the CWA is predicted to
experience a Hard Freeze Tuesday night into Wednesday morning. Our
forecast leans towards the colder guidance which shows 10s across
most inland areas and 20s closer to the coast. But these values
will be highly dependent the storm`s ability to establish a good
sleet and snow pack. A gradual warming trend is expected during
the second half of the week. But temperatures look to remain
cooler than normal through Friday.

Self

&&

.AVIATION...
(06Z TAF Issuance)
Issued at 1056 PM CST Fri Jan 17 2025

VFR conditions will prevail through the next few hours, but MVFR
CIGs of 1500-2500ft will begin to build in along the coast and
expand inland to around IAH by 9z. Some patchy fog is also
possible along the coast, mainly impacting LBX and SGR. There is
a LLJ around 2000ft with winds up to 40-45kt across the area that will
persist through the around 12z. Conditions improve back to VFR
after sunrise tomorrow. A cold front will move through the region
tomorrow morning creating a northwesterly wind shift and bringing
wind gusts to 20-25kt through the afternoon. FROPA will occur at
CLL around 10-12z, IAH 11-14z, and GLS 13-16z.

Fowler

&&

.MARINE...
Issued at 135 AM CST Sat Jan 18 2025

Southerly well should beging to decrease today as offshore winds
increase in the wake of a cold front. However, seas are likely to
increase again by tonight as persistent fresh to occasionally
strong northerly winds continue. Winds and seas may decrease
somewhat on Sunday. However, this will be short-lived as the
gradient steepens between a developing low near south Texas and a
building arctic high to the north. Northeast winds will increase
on Monday into Tuesday. Gales appear likely over the Gulf and
possible at the coast and in the bays. Some of the guidance
suggests gusts to storm force offshore. Seas will build during
this time as well, easily reaching 10-15 feet offshore and
possibly reaching 10 feet nearshore. Winds and seas should
gradually subside by Wednesday and Thursday.

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)  56  29  42  23 /   0   0   0   0
Houston (IAH)  61  32  45  26 /   0   0   0   0
Galveston (GLS)  62  36  45  33 /   0   0   0   0

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...Cold Weather Advisory from midnight tonight to noon CST Sunday
     for TXZ163-164-176>179-195>200-210>212-300.

     Cold Weather Advisory from 3 AM to noon CST Sunday for TXZ213-
     214-226-227-235>238-313-335>338-436>439.

GM...Small Craft Should Exercise Caution through this afternoon for
     GMZ330-335-350-355.

     Small Craft Advisory until 6 AM CST early this morning for
     GMZ370-375.

&&

$$

SHORT TERM...Luchs
LONG TERM....Self
AVIATION...Fowler
MARINE...Self