683
FXUS64 KHGX 221805
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
105 PM CDT Wed May 22 2024

...New AVIATION...

.SHORT TERM...
(Today through Thursday Night)
Issued at 324 AM CDT Wed May 22 2024

Have made some fcst adjustments this evening and tonight worth
noting across the northern 1/3 of the CWA.

This morning, we`ll see some shortwaves moving over the top of broad
mid level ridging situated over Mexico and South Texas and across
the region. Column becomes fairly saturated from 600mb on up for
inland parts of the region, but a significant dry subcloud layer
along with capping should keep things limited to light rain or
sprinkles - if anything.

This afternoon, anticipate shower and tstm development across north
Texas along a frontal boundary. This activity will probably back
build to near the dryline and eventually congeal s/sewd moving line.
Along with higher PW values pooling ahead of the front, the
atmosphere will be much more unstable up that way. The question now
becomes is how far south this convection gets before losing
instability, encountering some capping ~700mb (most pronounced as
one gets closer to the coast), and eventually dissipating.

The vast majority of the 00z model guidance indicates a further
south qpf field than earlier runs...and the CAMs even more so. If a
significant enough cold pool develops behind the convection, it`s
not out of the realm of possibility that this line, and associated
risk of strong winds and hail, could make its way into the northern
1/3 of the CWA in the 6pm-midnight timeframe before decaying and
dissipating. Several of the 00z HREF members were quite salty in
regards to potential storm intensity, but the 6z HRRR run has backed
off a touch. A difficult forecast with mesocale factors coming into
play, but those living north of about the TX-105 corridor should
keep track of the latest fcst if you have outdoor plans later this
evening. Have bumped POPs up there with a heavier weight of CAMs
mixed in. Also threw in the mention isolated severe storms in the
grids. Think the metro area itself will probably be too capped for
significant wx, in addition to increasingly less favorable timing.

Otherwise, warm/muggy conditions will prevail through the period.
Continued moderate onshore winds and elevated dewpoints will keep
readings 5-9F above normal - most notable at night with the lack of
a substantial cooling period.  47

&&

.LONG TERM...
(Friday through Tuesday)
Issued at 324 AM CDT Wed May 22 2024

I wish that I had better news for y`all about the forecast, but
everything is still on track for this period of well above normal
temperatures to continue. Prepare for a holiday weekend of
sizzling...and we`re not just talking about the barbecue grill!
Upper level riding aloft continues to prevail with an upper level
high remaining over northern Mexico into the weekend. There are some
rain chances to talk about along with an approaching frontal
boundary, but don`t let that distract you from making preparations
to stay safe from the heat over the upcoming days...especially those
with outdoor plans for the holiday weekend.

On Friday, we`ll have a weak surface low over north Texas with a
frontal boundary draped across the state. Since we`ll be in the warm
sector, our humidity will be fairly high. So, even though high
temperatures will be in the low to mid 90s...it`ll feel like it`s
101-105F. Temperatures continue to climb over the weekend as
southwesterly flow aloft becomes established around 850mb leading to
850mb temperatures approaching their MAX percentiles (NAEFS/GEFS).
Some of this warmer air aloft will be able to mix down to the
surface leading to increasingly hotter temperatures. On Saturday,
we`re looking at more locations reaching the mid 90s. On Sunday,
most locations north of I-10 look to reach the upper 90s. Now
remember that frontal boundary mentioned earlier? It`s still
meandering around just west of central Texas, so we remain in the
warm sector with plentiful humidity. As a result, expect heat index
values to approach and maybe even exceed our Heat Advisory criteria
(greater than or equal to 108F) as heat index values will be well
into the 100s. The crazy thing is...the weekend isn`t even the peak
of this round of heat!

Monday/Memorial Day will be the hottest day of the year (the hottest
day of the year so far!) with most locations topping out in the
upper 90s. The lone exception will be those along the coast, but
even then it`s still going to feel well above 100F for all of us.
Forecast heat index values continue to point towards the likelihood
of a widespread Heat Advisory with values ranging from 107-112F.
The timing of the frontal boundary getting closer as it gets a push
from a passing upper level low in the Central Plains does play a
role here due to compressional heating out ahead of the front. Now
let`s talk about heat risk. Friday through Monday most of the area
is outlined in a "Major" risk (level 4 out of 5) which means that
this level of heat affects anyone without effective cooling and/or
adequate hydration. There won`t be much relief during the overnight
hours either as low temperatures will only bottom out in the upper
70s to near 80F. The average first day of 95+F temperatures for
the City of Houston is June 13th, so this is an early season bout of
heat and our bodies are not yet acclimated to it. This is occuring
on a holiday weekend and we know that you may have outdoor plans, so
PLEASE be sure to practice heat safety to protect yourselves and
your loved ones. Drink plenty of water, take frequent breaks from
the sun, avoid strenuous outdoor activities during the hottest part
of the day, wear loose/lightweight clothing, know the signs of heat
stroke/heat exhaustion, and ALWAYS ALWAYS ALWAYS look before you
lock your vehicle. Don`t forget about your pets as well! If the
ground is too hot for the palm of your hand, then it is too hot for
their paws. Don`t forget the sunscreen too!

It`s still a bit too early to place too much faith in the frontal
boundary actually pushing through southeast Texas late Monday, but
if it does then it`ll bring a chance of rain mainly for locations
north of I-10. Even beyond the front, things look a bit uncertain
into early next week as far as if we`ll see continued rain chances
or if the next building ridge cuts us off from any meaningful rain
chances again. Only time will tell!

Batiste

&&

.AVIATION...
(18Z TAF Issuance)
Issued at 1234 PM CDT Wed May 22 2024

Ceilings have been improving and we should see mostly VFR conditions
across the CWA this afternoon into the early evening hours. Isolated
to widely scattered showers have been moving across the region since
this morning (despite the strong cap in place), but not too sure how
much is actually reaching the ground. However, near term guidance is
continuing to indicate that we`ll see a round of stronger more organ-
ized activity approach and move across the area (mainly the northern
to central CWA) starting late this afternon into evening. Have added
a TEMPO group for our two most northern terminals (CLL/UTS) with the
mention of VCSH to CXO. This may need to be extended south to IAH if
model trends continue to push things south. Otherwise...look for the
return of MVFR/IFR ceilings overnight...with improving conditions by
mid to late morning tomorrow. 41

&&

.MARINE...
Issued at 324 AM CDT Wed May 22 2024

Generally moderate onshore flow will continue into the weekend.
Winds and seas will periodically increase enough for caution flags
and possibly advisories. After midweek, seas (especially in the
offshore waters) will become elevated in the 4-6 ft range. The
persistent onshore flow will bring a high risk of rip currents
through the end of the week.

Batiste

&&

.HYDROLOGY...
Issued at 324 AM CDT Wed May 22 2024

Minor to major river flooding continues for parts of Southeast
Texas, particularly along portions of the Trinity and Brazos rivers.
The following river points are either currently in flood stage
(as of ~3AM Wednesday morning):

MAJOR//
-------
- Trinity River (Liberty): Major

MODERATE//
----------
- Trinity River (Riverside): Moderate
- Trinity River (Moss Bluff): Moderate

MINOR//
-------
- Trinity River (Goodrich): Minor
- Brazos River (Richmond): Minor
- Brazos River (Rosharon): Minor
- Brazos River (Sugar Land): Minor

Remember to heed any instructions from your local officials and to
never travel through ANY flooded areas or roadways. TURN AROUND,
DON`T DROWN. Please monitor updated forecasts via the NWS AHPS
website and/or the new NWS NWPS webpage (https://water.noaa.gov/) as
the river flooding continues.

Batiste

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)  93  77  92  77 /  20  50  10  10
Houston (IAH)  90  79  92  78 /  10  20  10   0
Galveston (GLS)  86  80  87  81 /  20  10  10  10

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...High Rip Current Risk until midnight CDT tonight for TXZ436>439.

GM...Small Craft Should Exercise Caution from 4 PM CDT this afternoon
     through Thursday evening for GMZ330-335-350-355-370-375.

&&

$$

SHORT TERM...47
LONG TERM....Batiste
AVIATION...41
MARINE...Batiste