498
FXUS64 KHGX 270915
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
415 AM CDT Mon May 27 2024

...New SHORT TERM, LONG TERM, MARINE...

.SHORT TERM...
(Today through Tuesday Night)
Issued at 251 AM CDT Mon May 27 2024

Key Messages:

- Excessive Heat Warning in effect until 10 PM tonight for portions
of SE Texas

-Heat Advisory in effect until 10 PM tonight for locations outside
of the Excessive Heat Warning

-Marginal Risk for severe weather tonight and Tuesday for much of SE
Texas


The hottest day in our streak of hot weather days has arrived, and
following today`s heat indices of 115-115 degrees we will begin to
see a slight (and very gradual) decrease in HI values through the
rest of the week. For today though...With this being an
extraordinarily hot day, and a holiday, please remember to take
precautions in the heat!

If you plan to beat the heat by taking a dip in the Gulf, continue
to practice beach safety. We have received a few reports of people
becoming caught in rip currents this holiday weekend, and today will
feature another high risk for rip currents. If you find yourself
caught in a rip, remember to wave, yell, and swim parallel to the
shore. Avoid swimming near piers and jetties where rip currents are
more likely to develop.

In addition to the heat and beach safety, there is a risk for severe
weather later today (looking like the evening to just before
midnight time frame) and again on Tuesday. SPC has outlined most of
the area in a Marginal Risk (level 1 of 5) for both Monday and
Tuesday.

The severe weather threat is conditional on whether or not the
robust cap in place over the area erodes ahead of the storms. Hi-Res
guidance has varied run-to-run on location and strength of storms,
with the latest HRRR showing the storms dying off as they approach
the Brazos Valley.

Digging a little deeper into the setup, 500mb level shows a quasi-
zonal flow with a few disturbances and pockets of PVA traversing SE
Texas this evening into tonight. Further west a boundary is expected
to setup over Central Texas which will trigger storms out towards
the San Antonio area. These storms will track southeast and if the
cap holds together, they should weaken upon arrival; however, if the
cap is able to erode (could happen with daytime heating, cooling off
in the mid-upper levels, outflow boundary interactions), storms would
have plenty of CAPE to work with. They would also have the potential
to become organized with decent shear. This would lead to the
potential for damaging winds, large hail, and a brief isolated
tornado.

Overnight Monday into Tuesday morning will feature more tranquil
weather. Lows will be in the 70s to around 80s with pretty humid
conditions.

NW flow will take over Tuesday and will help trigger the next threat
of severe weather from that direction during the evening hours. As
mentioned in the previous discussion, this setup has the tendency to
be more conditional with the threat for severe thunderstorms.
Highest PoPs lie in the NW counties. Strength and longevity of
storms will largely depend on the erosion of the capping inversion
and timing of arrival for PVA. Damaging winds and hail will be the
main hazards with any storms that are able to make it into SE Texas.

In any case, have multiple ways to receive alerts today and Tuesday.

&&

.LONG TERM...
(Wednesday through Sunday)
Issued at 251 AM CDT Mon May 27 2024

Less hot, but somewhat unsettled pattern takes shape as upper
ridging retreats a bit further southeast. This will allow
disturbances embedded in the wnw-nw flow aloft to track a bit
further south into the region. Low-mid level capping will also be
less dominate from keeping shra/tstms from developing or
maintaining themselves as they move in.

A continued onshore flow will prevail and sufficient moisture will
be available for scattered precip across portions of the CWA each
day. The main forecast challenge is determining the more
favorable time periods for convection. Guidance has been
indicating the potential for upstream development, maybe an MCS or
two, during the last half of the week...but at varying time
periods and locations. This is typical for such a pattern and
makes the POP fcst difficult - especially when the mesoscale comes
into play. Suspect NBM is substantially too low with POPs for a
good part of the extended fcst, but I really cannot say exactly
when. For the grids, I did about a 50% mix NBM and a 50% mix of
various deterministic models and WPC guidance.

At this time, wouldn`t be overly surprised if early Wed morning,
Wed night-Thursday morning, and Friday daytime/evening might be
the more favorable times...with northern parts seeing better
chances than the coast. But again, forecast confidence in regards
to the specifics is fairly low. 47

&&

.AVIATION...
(06Z TAF Issuance)
Issued at 1122 PM CDT Sun May 26 2024

We will continue to transition over to mostly MVFR ceilings through
the overnight hours across the area as mostly light S/SE winds pre-
vail. These lower CIGS will be slow to clear Mon morning especially
closer to the coast. Further inland, a weakening cap and additional
disturbances moving in from the west could produce scattered storms
over our W/NW counties tomorrow afternoon/evening. Near-term models
appear to be keeping with this trend of increasing POPs...but still
going to keep the mention of precipitation out at this time. 41

&&

.MARINE...
Issued at 251 AM CDT Mon May 27 2024

Winds and seas decrease somewhat today into the early and midweek
time period. That said, recreational mariners are urged to use
extra caution today considering the increased holiday traffic.
Will maintain the Beach Hazards Statement through this evening
along area beaches due to excessive crowds and the number of
rescues reported by Galveston Beach Patrol the past 2 days.

During the second half of the week, moderate to occasionally
strong southeast winds and 4 to 6 foot seas resume with a long
fetch setting up across the Gulf. Showers and thunderstorm chances
return to the forecast late Tuesday night and Wednesday. Though
chances are better inland, we anticipate some disturbances passing
through this week that are difficult to time days in advance.  47

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)  96  76  92  74 /  20  20  20  30
Houston (IAH)  97  78  93  77 /  20  20  20  20
Galveston (GLS)  89  79  87  80 /  10  10  10  10

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...Heat Advisory until 10 PM CDT this evening for TXZ163-164-
     176>179-195-196-198-200-214-235>238-300-313-335>338-436>439.

     Excessive Heat Warning until 10 PM CDT this evening for TXZ197-
     199-210>213-226-227.

     Beach Hazards Statement through this evening for TXZ436>439.

GM...None.

&&

$$