952
FXUS64 KHGX 231756
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
1156 AM CST Mon Dec 23 2024

...New AVIATION...

.SHORT TERM...
(Today through Tuesday Night)
Issued at 312 AM CST Mon Dec 23 2024

Since today is Festivus (for the rest of us), we can finally air out
some grievances with Mother Nature...my main one being that
Christmas should ALWAYS be cold! Shorts and flip-flops shouldn`t be
needed to be comfortable on Christmas Day...but I digress. With
surface high pressure off to our east and a developing area of
surface low pressure currently near the TX/OK panhandles placing us
in its warm sector later today, we`ll have plenty of WAA and
moisture advection to go around. This will lead to high temperatures
today mainly in the low to mid 70s, which is nearly 10F above
normal. The trend of warmer temperatures continues through midweek,
so now you have an early idea of what Christmas Day will be like.

PW values by this afternoon will be around 0.9"-1.1", which is
approaching the 75th percentile (~1.12"). The latest CAMs continue
to show isolated to scattered rain showers offshore and around
Matagorda Bay throughout the afternoon. There remains a dry layer
extending from the surface up to ~1km AGL and the layer of moisture
looks rather shallow, so not expecting much more than sprinkles to
light rain to reach the surface today. That won`t be the case on
Tuesday (Christmas Eve)...the next paragraph is important if you`re
planning on traveling for the holiday (especially if you`re
traveling by sleigh). A 25-30 kt LLJ slides in over portions of the
Brazos Valley going into tonight, which could play a role in
inhibiting fog development. The highest potential for patchy fog
will be for locations west of I-45 and south of I-10 tonight into
Tuesday morning. Expect low temperatures to range from the upper 50s
to low 60s. Now let`s get to what y`all are really here to read
about...

By Tuesday, we`ll have dew points reaching the low 60s as surface
low pressure continues to scoot eastward along the Red River and
dragging a frontal boundary towards Southeast Texas. PW values ahead
of the front reach the 1.2"-1.4" range (90th percentile: ~1.37"), so
we`ll have plenty of moisture in place to be lifted by increasing
PVA from an approaching mid level shortwave. The environment ahead
of the approaching front does look marginally favorable for a few
storms to become strong to severe on Tuesday afternoon/evening with
modest instability available (600-1000 J/kg CAPE) and steep 700-
500mb lapse rates (~7.0C/km). Bulk shear is on the low side though
(~30 kts), so if a storm were to become strong to severe it likely
wouldn`t be able to maintain itself for a long period of time. Any
of the stronger storms would be capable of producing strong wind
gusts, marginally severe hail, and locally heavy rainfall, which is
why SPC has outlined areas north of a Wharton-Pearland-Liberty line
in a marginal risk (level 1 out of 5) of severe weather for Tuesday.

Locally heavy rainfall was mentioned as well as there are some
synoptic features at play to help with that: upper level divergence
(left exit region of jet streak), frontogenetic forcing from the
approaching weak front, and convective enhancement from a 25-30 kt
LLJ. As a result, WPC has outlined essentially the same area in a
marginal risk (level 1 out of 4) of excessive rainfall. Most will
see rainfall totals of less than an inch, but the previously
mentioned ingredients line up the best across the Brazos
Valley/Piney Woods especially on Tuesday evening/night. I wouldn`t
be surprised to see isolated higher totals across that region. This
means that Santa will definitely need Rudolph to be well rested as
his nose will be needed to route through some rainfall. Speaking of
Rudolph...his song mentions "one foggy Christmas Eve", and it does
have the potential to be that for some on Tuesday night due to
rainfall from earlier in the day and light winds overnight. This
appears to be most likely for locations south of I-10, so it
technically could be a "white Christmas"...just not the kind that
everyone wanted. The progression of the weak front remains in
question as some model guidance pushes it through to the coast by
sunrise on Wednesday (Christmas) morning and others stall/wash it
out beforehand. If you were curious about the temperatures on
Christmas Eve, it`s essentially a copy-pasta of Monday`s.

Batiste

&&

.LONG TERM...
(Wednesday through Sunday)
Issued at 312 AM CST Mon Dec 23 2024

Rains/storms from the first storm system will be exiting the area off
to the east on Wednesday morning (Christmas Day). Look for high temperatures
in the 60s/70s. The weather Wednesday afternoon looks mostly quiet,
and this pattern will only persist through Thursday morning (lows Wednesday
night will be in an upper 50s to lower 60s range for much of the area).
Beginning Thursday afternoon, the next storm system then will begin
to work its way across our area. Best shower/storm chances will be Thursday
afternoon (high temperatures in the 70s... maybe close to 80 towards
the Matagorda Bay area) through Thursday night (low temperatures in
the 50s/60s). Some rain could linger around Friday morning through Friday
evening (highs Friday in the similar to Thursday...in the 70s and maybe
close to 80 towards the Matagorda Bay area), but better chances come
again Friday night through Saturday as the final weaknesses/disturbances
edge eastward across the state. Lows Friday night will be in the 50s/60s
and highs on Saturday will be...again...in the 70s and maybe close to
80s towards the Matagorda Bay area. Winds will finally shift to the
north on Saturday afternoon/evening behind a cold front and will help
to dry the area out for the rest of the weekend. Lows on Saturday night
will cool back down (40s/50s), and highs on a less humid Sunday will
be in an upper 60s to low 70s range.  42

&&

.AVIATION...
(18Z TAF Issuance)
Issued at 1153 AM CST Mon Dec 23 2024

VFR conditions will prevail through the evening with cloud
coverage increasing over the course of the afternoon as SE winds
bring more moisture into the area. A few spotty showers will be
possible, but coverage is expected to be low enough not to be
included in the current TAF package. Overnight, lowering cigs may
approach MVFR levels at times with rainfall coverage picking up in
the morning and increasing further into the afternoon. A few
embedded thunderstorms can`t be fully ruled out, but have opted to
keep PROB30 wording for SHRA for the time being given lower
confidence in the location of any stronger storms that could
develop during the afternoon.

Cady

&&

.MARINE...
Issued at 312 AM CST Mon Dec 23 2024

Light to moderate south to southeast winds will persist for much of
the week. Caution thresholds could be reached at times. Patchy fog
could occasionally develop too. Some rain is possible today, but better
rain chances begin tonight and continue through Wednesday morning as
a storm system moves into the area. At this time, Wednesday afternoon
through Thursday morning looks quiet. More rains can be expected
Thursday afternoon through Friday morning as a second system moves on
through. Our next cold front currently looks to move across Saturday
afternoon or evening with offshore winds developing in its wake. 42

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)  74  61  75  58 /   0  20  60  70
Houston (IAH)  72  61  74  61 /  10  20  40  60
Galveston (GLS)  70  63  71  63 /  10  20  30  50

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...None.
&&

$$

SHORT TERM...Batiste
LONG TERM....42
AVIATION...Cady
MARINE...42