384
FXUS64 KHGX 121127
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
627 AM CDT Wed Mar 12 2025

...New AVIATION...

.SHORT TERM...
(Today through Thursday Night)
Issued at 308 AM CDT Wed Mar 12 2025

Surface high pressure that yesterday was over the northwest Gulf has
drifted eastward across the waters, giving us more southerly flow
today. Additionally, a low pressure center is developing over
Oklahoma, tightening up the pressure gradient over much of Texas for
today. As a result, we`ll be looking a warm, breezy day across the
area, with winds that will be boosting low level humidity through
the day. Satellite imagery shows we are seeing some patchy fog near
the coast and low stratus developing farther inland that we
typically see with solid moisture return. Those should persist and
expand through the rest of the overnight hours and shortly into the
morning, dissipating as the sun rises through the morning. By early
afternoon, we should be back to mostly or fully sunny across the
area, helping push us to afternoon highs in the upper 70s and lower
80s.

One thing to consider this afternoon will be the overlap of those
breezy conditions with low RH, as we had quite a dry day yesterday.
If you`re really interested in the details, there`s a fire weather
section down below, but the key here is that today`s winds will be
backed enough to have a solid connection to the Gulf. So, despite
the breezy and warm conditions, humidity should be pretty safely
above any critical thresholds as far as a red flag warning goes.
That said, it`s breezy enough that if you are not a professional
prescribed fire practitioner, you want to be pretty cautious with
any fire use today, or you know...just maybe find an alternative to
burning for today...and the next several days.

Okay, so I mentioned a surface low - that`s gonna come through with
a cold front and showers and storms and cooling, right?
Well...uh...kinda...sorta? But not really? Here`s the situation:
we`ve got that Oklahoma low, and it should get dragged more or less
due east as an upper through drives through Oklahoma and Arkansas.
This is probably a more useful track for more showers and
thunderstorms, but we got a couple real big brakes on any sort of
stormy setup here. One is moisture - precipitable water is only
around 0.5 inches early this morning. The strong Gulf inflow is
going to push that upwards, but there`s not much time. The HREF mean
only gets peak values around 1 inch along the front when it rolls
through the area. Even the 90th percentile HREF PWAT numbers max out
around 1.25 inches. On top of that, forecast soundings are STRONGLY
capped. Mean HREF CINH finds a small pocket of -65 J/Kg at most,
strongly implying that the cap simply never breaks in our area. The
75th percentile CINH numbers do indicate the cap could break in our
north, probably if we bulk up low level heat and humidity more than
expected, but the odds are certainly against it. In what I`m sure is
a complete and total coincidence (sarcasm detector check!) the SPC
Day 1 outlook paints a marginal risk across our northern third,
right where we could see the cap break if an unusually supportive
environment pans out. My PoPs are showing a slight chance of rain
(or less!) but yes...if something does find a way to pop, it will
likely be off to the races.

Okay, now for the even more "not really" part. This "cold" front is
not really vigorous. It`s mostly analyzed this way as it is relative
to the passing surface low. Functionally, it`s more useful to treat
it like the dryline that the front is overtaking and shoving through
the area. Look for PWATs to plummet behind the dryline/front/thingy,
down below half an inch and into the quarter to third inch range
with dewpoints into the 40s inland. And, like a good dryline, the
air is probably going to heat very effectively on the dry side of
it, which means highs tomorrow should shoot well into the 80s for
all but the immediate Gulf coast. Does someone around Matagorda Bay
hit 90 degrees? I`m not expecting it to be common, but I bet
*someone* manages to pull it off. With the hot, dry conditions, look
for minimum RH values to fall below 30 percent for everyone not
right on the coast, and folks in the far west should look to see RH
dip below 20 percent in the afternoon.
And yes, you guessed it - you can read more on this in the fire
weather section below.

Finally, after a brief southwesterly dalliance behind the
front/dryline, winds should quickly snap back to southerly as the
pattern upstream reloads with another Plains low/upper trough.
This will restart moisture advection from the Gulf, and set us up
for the long term section next up!

&&

.LONG TERM...
(Friday through Tuesday)
Issued at 308 AM CDT Wed Mar 12 2025

Unseasonably warm and humid conditions will continue as we head
into the weekend ahead of the passage of our next frontal
boundary on late Friday/Saturday. For Friday, the synoptic
pattern will be characterized by a rapidly deepening surface low
along the leeside of the Rocky Mountains, with resultant increases
in the strength of the surface pressure gradient promoting a
robust onshore wind regime. The resultant moist advection will
push dew point values into the mid to upper 60s across portions of
the area as a cold front associated with the aforementioned low
moves into the Southern Plains. High temperatures on Friday will
again reach the mid to upper 80s for most locations...perhaps not
a record-breaking event but likely only a few degrees off.

Thunderstorm potential associated with this system`s approach
continues to look even less favorable for the area in the most
recent suite of global model runs. Forecast soundings show SB
instability maxing out in the 500 - 1000 J/kg range, and also
show the presence of a fairly strong capping inversion at around
850 mb. Thus, while effective shear still remains fairly high,
convective initiation will be a struggle and it`s possible we now
don`t see much in the way of storm coverage. The greatest chances
for development generally lie to the east of I-45, where SB
instability is slightly more favorable. Any storms that do develop
could pose a severe weather threat given the shear environment.
However, these chances remain low for the time being.

A fairly benign weather pattern will follow the passage of the
front with broad surface high pressure settling into the South
Central CONUS. Light to moderate offshore winds will result in
persistent CAA, pushing overnight lows on Saturday and Sunday
nights into the upper 40s to lower 50s. Highs through Tuesday will
generally sit in the mid to upper 70s, perhaps exceeding 80 at
times. By late Tuesday/Wednesday, the area of high pressure will
have departed to the east, and the resultant onshore flow pattern
will result in increases in temperature in moisture towards the
end of the week.

Cady

&&

.AVIATION...
(12Z TAF Issuance)
Issued at 627 AM CDT Wed Mar 12 2025

Poor conditions for the pre-dawn and early morning hours, with a
swath of low CIGs scraping up the western and northern reaches of
the area, including impacts to CLL and UTS. CXO and SGR are on the
fringe, and while they may not see CIGs, both are known foggy
spots, and are likely to see that for the first few hours as well.

Once clouds and fog dissipate later in the morning, will quickly
become VFR area-wide with gusty south winds. Gusts should drop off
with sundown, but likely will see another round of low CIGs and/or
fog as moisture pools ahead of a weak front late. In the IAH
extended, clear and dry post-frontal airmass comes into the
picture.

&&

.MARINE...
Issued at 308 AM CDT Wed Mar 12 2025

Caution flags remain in effect today for the nearshore/offshore
zones as onshore winds increase to around 15 to 20 knots. Wind
speeds may approach advisory thresholds at times, but should
generally remain just under criteria. Patchy marine fog is
possible on Thursday morning, but fog development is expected to
be hampered by elevated wind speeds. A weak frontal boundary will
move offshore later today, resulting in a shift to southwest
winds. Moderate onshore winds and building seas return through
Saturday, when another frontal boundary will move offshore and
bring a shift to offshore winds.

Cady

&&

.FIRE WEATHER...
Issued at 308 AM CDT Wed Mar 12 2025

This week continues to feature periods of strong winds. And it also
continues to feature periods of *very* dry air. And fortunately for
our area...they largely don`t seem to overlap very much in Southeast
Texas. Still, because each day this week will be at least either
windy or very dry, it will be well advised to put strong thought
into the goals and needs when it comes to using fire. As far as
getting an overlap of both features, Friday is likely the day where
this has the best potential, particularly in the northwestern part
of our area (Burleson, Brazos, Madison counties, etc). Here`s a
daily breakdown of what stands out to this forecaster coming up:

- Yesterday is over, but worth noting that it was a dry day, with RH
largely below 40 percent across the area, and below 30  percent
south of Lake Livingston.
- Today will see much stronger winds than yesterday. Fortunately,
because of where the developing surface low is, these winds  should
be southerly enough that we get a strong Gulf connection.
  This is partially fueling the severe weather threat around the
ArkLaTex later, but also will mitigate the low humidity we saw
yesterday.
- Tomorrow will flip things back around. We will be in a *very*  dry
airmass after the front/dryline/whatever moves through, and  unless
you`re on right on the Gulf, you should expect RH to fall  below 30
percent, and those well west of the Houston metro can  probably
expect RH to cross the 20 percent mark. Winds veering  more
southwesterly will not help, as it cuts off the Gulf  connection and
instead is a hotter, drier, downsloping wind off  high terrain in
Mexico. On the plus side, because this front and  low are pretty
weak, winds will not be nearly as strong as it  heads off to the
east. So as the RH danger dial cranks up, the  wind dial will be
backing off.
- Friday is likely to see the driest air retreat back to the west
  with the dryline as winds become more southerly again Thursday
  night and Friday morning. But this day opens up the possibility
  that we get some overlap of low RH and stronger winds without
  one overwhelming the other. The spot to really watch is well
  inland where it will take more time for dewpoints and RH to
  rise, especially given the hot temperatures expected. I`m most
  keeping an eye on our northwestern corner, which will struggle
  to see dewpoints track up - both because of how far inland it
  is, and because winds do look to veer southwesterly again ahead
  of the next front. With strong enough winds, we could see an
  elevated to locally near critical fire weather set up Friday
  afternoon. One mitigating factor will be fuels - multiple days
  of low RH means lighter 1 to 10 hour fuels will still be quite
  receptive to fire, but more moist heavy fuels are keeping
  forecast ERCs in the 20th to 30th percentile and will hopefully
  mitigate more widespread fire weather issues.

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)  82  53  87  60 /   0  10   0   0
Houston (IAH)  81  61  88  61 /   0  10   0   0
Galveston (GLS)  72  62  74  64 /   0  10   0   0

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...Small Craft Should Exercise Caution through Thursday morning for
     GMZ350-355-370-375.

&&

$$

SHORT TERM...Luchs
LONG TERM....Cady
AVIATION...Luchs
MARINE...Cady