Area Forecast Discussion
Issued by NWS Houston/Galveston, TX

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152
FXUS64 KHGX 131136
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
636 AM CDT Thu Jun 13 2024

...New AVIATION...

.SYNOPSIS...
Issued at 400 AM CDT Thu Jun 13 2024

For better and for worse, attention for the forecast is focusing
on the potential for tropical development in the southwestern Gulf
of Mexico. On the one hand, keeping an awareness of potential
weather hazards is good! Staying aware is a key part of good
hurricane preparation. It`s also important, though, to keep things
in perspective, and evaluate everything in the whole context of
the forecast. There is no need to place excessive importance on
single model runs, especially for one deterministic model.
This is particularly true in the pre-development phase, where
confidence is quite low in the specifics of the evolution of a
storm (that may or may not even form!) that isn`t expected to even
exist for several days. Here`s what we can speak of with
confidence at this point:
- Regardless of whether a tropical cyclone develops or not, there
  is confidence that next week will feature disturbed weather for
  Southeast Texas, including gustier winds and increased
  potential for rain and thunderstorms.
- Continue to monitor trusted sources of information, such as this
  office and the National Hurricane Center, for the latest
  forecast information. Consider new information in a broad
  context. Good questions to ask yourself are: "Is this new
  information complementary to what these trusted sources have
  said previously, or is it wildly different?"; "What are the
  trends in forecast changes? Are expectations getting more or
  less threatening?"; "Is the confidence in the forecast
  increasing or decreasing?"
- The best day to have your hurricane preparations for the season
  ready is June 1. The second best day is today (or as soon as you
  can reasonably complete them). Many hurricane preparations can
  be made for an entire season, leaving you less to do when a
  storm does threaten. The more preparation you can have out of
  the way early, the less you will need to accomplish under the
  stress of an incoming storm.

&&

.SHORT TERM...
(Today through Friday Night)
Issued at 400 AM CDT Thu Jun 13 2024

With surface high pressure sinking south into the Lower Mississippi
River valley...rain chances will be decreasing across much of SE TX
today and tomorrow. Lingering deeper moisture (PWs around 2") along
the coast/SW counties should help to fuel scattered showers/thunder-
storms with the seabreeze moving inland through this afternoon. For
the most part, rainfall totals are expected to average around 1/2-1
inch with higher totals in the stronger storms (1-2"). Any activity
that does get going today should weaken/be gone by this evening.

Elsewhere across the CWA today, the much lower/nil rain chances are
going to lead to warmer temperatures. And, with the wet grounds and
light winds already in place, heat index values up to 105F might be
possible this afternoon at some locations. Otherwise, highs will be
in the lower to mid 90s. Lows tonight (and tomorrow night) are prog-
ged to be in the lower and mid 70s (to around 80 along the beaches).

With the ridge aloft building in from the west and the surface high
staying put over the Lower Mississippi...POPs are going to decrease
even further tomorrow...even along the coast. So Fri should feature
very warm daytime temperatures across the region, with highs in the
mid 90s for most locations but some readings into the upper 90s are
going to be possible. Fortunately, slightly drier air aloft will be
filtering in/mixing down over the region with this pattern. And this
could help to temper heat index values a bit...with indicies likely
staying around 100F. Not *that* bad, but still within normal ranges
for SE TX summers.

&&

.LONG TERM...
(Saturday through Wednesday)
Issued at 400 AM CDT Thu Jun 13 2024

Saturday - yup, still looks hot. Expectations remain for high
temperatures in the lower 90s in the cooler spots, up into the
middle 90s, and even some upper 90s in the hot spots. Peak heat
index values look to generally be in the 101 to 107 range. That
said...my forecast this morning is ever so slightly cooler than
yesterday. Guidance is suggesting that the mid-level ridging
doesn`t come in quite as strong, as a trough in the northern
stream digs down far enough to keep a bit of a weakness in place
over us. It`s not a big deal...but perhaps enough to keep my
concern levels about needing heat advisories at a lower level.
That said, it`s still looking hotter than mid-June averages, so
heat safety remains a consideration for outdoor plans this
weekend.

Heat may be a continuing concern earlier on Sunday - both from low
temps being hung up in the 70s to even around 80 degrees at the
coast, and into mid-day/early afternoon. With deeper moisture
anticipated already, we won`t mix out humid conditions as much in
the afternoon, and we could still see peak heat index values well
into the triple digits. Eventually, though, Sunday will also give
us our transition to next week`s stormier pattern. While shower
and storms will be nil to isolated far inland, we can expect more
scattered to widespread development over the Gulf waters and
coastal areas.

For the rest of the first half of next week, I don`t want to get
TOO too specific, as some details will certainly depend on the
evolution of our expected friend in the southwestern Gulf (more on
that in the tropical section below), but there are certainly some
more broad-brushed things we can say with more confidence at this
point. An inverted upper trough over the Bay of Campeche will help
keep a weakness in the subtropical ridge in place over the eastern
half of Texas. This may help play a part in the development of
surface low pressure, which may be tropical, but it will also help
keep heights down modestly for us, allowing for more daily
convective development over Southeast Texas. This is complemented
by a surge of a Gulf airmass with deeper moisture that will make
potential for showers and thunderstorms more likely through the
first half of next week. This will be an expectation regardless of
the status of tropical development in the Gulf.

Increased onshore flow is also a fairly high confidence
proposition, with our area expected to see a tighter pressure
gradient between whatever low pressure thingamajig is happening
over the Gulf and high pressure over the Eastern Seaboard.
Temperatures during the daytime will be seasonably hot, but a bit
cooler than the forecast for tomorrow/Saturday, thanks to
increased cloudiness and rain coverage. At night, however, we may
be looking at a different scenario - as onshore flow continues to
pump humid, low-level air into Southeast Texas, we may be looking
at overnight lows drifting higher into the 70s across the area the
deeper we get into the week.

&&

.AVIATION...
(12Z TAF Issuance)
Issued at 624 AM CDT Thu Jun 13 2024

Patchy fog/low clouds this morning should mix out shortly with VFR
conditions prevailing across much of the CWA. The exception should
be along/near the coast with seabreeze activity. Did add a mention
of VCSH in for LBX and GLS for this afternoon (15Z through 20-21Z).
Otherwise, a fairly quiet forecast. 41

&&

.MARINE...
Issued at 400 AM CDT Thu Jun 13 2024

Generally light onshore flow and low seas should prevail through
the end of the week. There will be a daily risk of isolated
showers and thunderstorms generally diminishing through Saturday.
Storms may produce locally higher winds and seas along with the
potential for waterspouts.

Most of the attention on weather conditions, though, will likely
be focused on next week, with a medium probability (40 percent as
of 2am) of tropical cyclone development in the southwestern Gulf
of Mexico. Mariners should continue to monitor conditions in the
Gulf for next week, including the tropical weather outlook from
the National Hurricane Center, for the latest information. At
this time for our area, anticipate stronger winds and a
corresponding increase in seas along with increased potential for
showers and thunderstorms regardless of any tropical development
that may or may not not occur.

&&

.TROPICAL...
Issued at 400 AM CDT Thu Jun 13 2024

The area that the National Hurricane Center is monitoring for
potential tropical development has had its probability of
development increased to the medium range - 40 percent - over the
next seven days. The timeframe for development is still next week,
and the probability of tropical cyclone development in the next
two days is near 0 percent.

There remains good consensus in the model guidance that some sort
of low pressure center, and possibly a tropical cyclone will form
in the southwestern Gulf/Bay of Campeche, and drift west-
northwestward, eventually making landfall along the northeastern
Mexican coastline. Of course, even relatively consistent model
guidance must be taken with some more caution for a storm that has
not yet formed, as small scale changes in the formation process
could significantly change expectations.

Regardless of whether there is tropical cyclone development of
not, the broad impacts for our area are fairly consistent -
somewhat gustier winds due to a tighter pressure gradient, and an
influx of deep Gulf moisture to fuel more numerous showers and
thunderstorms next week. Continue to monitor forecasts from our
office and NHC into next week for the latest information.

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)  93  74  94  73 /   0   0   0   0
Houston (IAH)  93  76  95  74 /  10  10   0   0
Galveston (GLS)  89  80  90  81 /  30   0   0   0

&&

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

$$

SHORT TERM...41
LONG TERM....Luchs
AVIATION...41
MARINE...Luchs