415
FXUS64 KHGX 070449
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
1149 PM CDT Mon May 6 2024

...New AVIATION...

.SHORT TERM...
(This evening through Tuesday Night)
Issued at 246 PM CDT Mon May 6 2024

High humidity, gusty southeast winds, temperatures in the 80s,
and widespread low/mid level cumulus rule the day on this Monday.
Capping has prevented the aforementioned cumulus from growing into
organized shower/thunderstorm activity. Capping will keep PoPs
low, but not necessarily non-zero. Isolated shower and thunderstorm
activity will be possible, especially across our northern counties.
Some runs of the HRRR today are showing thunderstorms nearing our
Brazos Valley counties this afternoon. That remains to be seen
but also cannot be ruled out due to weak disturbances embedded in
the flow aloft. Tonight promises to be another muggy night
featuring a developing low cloud deck and patchy fog.

At first glance, tomorrow looks very similar to today. However,
one key difference will be the increasing ~850MB WAA. 850MB temps
are expected to be 3 to 5 degrees celsius higher tomorrow afternoon.
Diurnal mixing should allow this WAA to mix down to the sfc layer,
resulting in hotter temperatures tomorrow afternoon. How hot?
Many inland locations are likely to make a run for the 90 degree
mark. Meanwhile, high levels of humidity will make it feel about
10 degrees hotter than the actual temperature. Some guidance,
particularly the NBM, is quite aggressive with afternoon dew
points, indicating widespread values in the 75F to 77F range. If
that were the case, then heat index values could be another 3 to 5
degrees hotter than currently predicted. But since the NBM is
featuring a higher dew point bias today (not uncommon), we opted
to mix in some "drier" guidance to tame those afternoon dew points
down to 73-74F (still nasty).

Even though tomorrow`s heat is technically below advisory criteria,
these temperatures and dew points are quite high for early May.
Therefore, practicing heat safety is warranted. Heat safety
precautions include drinking plenty of water, wearing light
clothing, taking frequent breaks in the shade or indoors if
working or doing physical activity outside. If you think it`s
uncomfortable outside, so does your pet! Never leave children or
pets in the car this time of year (LOOK before you LOCK).

Self

&&

.LONG TERM...
(Wednesday through next Sunday)
Issued at 246 PM CDT Mon May 6 2024

You might be thinking "it`s too early for it to be this hot!" as you
see low 90s in the forecast through Thursday...so let`s take a brief
peek into the climatology (for the City of Houston). We have a high
temperature of 90F forecast for Houston on May 7th...the last time
our first 90+F day was this late was in 2018. Four out of the last
five years we`ve hit 90+F for the first time of the year in
March/April. Our average first day of 90+F temperatures is May 6th,
so we`re right around average...nut 90s are 90s so that`s hot no
matter what month it is. With southwesterly flow aloft persisting,
850mb temperatures will reach the 20-25C range Wednesday and
Thursday. This is around their 99th to MAX percentiles (NAEFS/GEFS),
so high temperatures in the low 90s are definitely supported. The
heat itself isn`t the only story...given the saturated soils from
the recent rainfall, humidity values will be a bit higher leading to
elevated heat index values (100-105F). Additional moisture moves in
on Thursday ahead of an approaching frontal boundary (we`ll get to
that soon), so this is the day we`re watching the closest for now
for a potential early season Heat Advisory since our bodies aren`t
acclimated to the heat just yet) in addition to lingering effects
from the previous rainfall in some areas (power outages & outdoor
clean-up efforts).

Now about that cold front! An upper level low will traverse from the
Northern Plains to the Great Lakes region midweek. The surface low
will follow a similar east-southeastward track through the Central
CONUS and drag a cold front towards Southeast TX. The cold front
will be sitting on our doorsteps as early as Tuesday morning, but
the parent low sits nearly stationary over the Northern Plains so
there won`t be much movement until the new surface low forms further
south midweek. We will be in the warm sector, so there`ll be plenty
of shear and instability to work with. Recall our elevated 850mb
temperatures though which is the source of our subsidence inversion
layer aloft (cap), so any storms that attempt to develop along and
ahead of the front will have to battle that. That cap is stronger
the further south you go on both Wednesday and Thursday. While there
is a slight risk of severe weather (level 2 out of 5) for portions
of Southeast Texas Wednesday/Thursday, it all depends on if any
convection can break the cap to tap into the elevated instability
and shear. Rain chances Thursday are mainly along and north of I-10
as the front pushes through the area and we`ll likely be too capped
further south for any storms to make it.

Temperatures do cool down a bit post-FROPA with highs on Friday and
over the weekend back into the 80s and overnight temperatures mainly
in the 60s. The surface high pressure that builds in on Friday
behind the front pushes eastward over the weekend allowing for
moisture to return. Rain chances remain over the weekend with
various shortwaves passing through, but most notably on Sunday as it
appears a coastal trough will drift through the area.

Batiste

&&

.AVIATION...
(06Z TAF Issuance)
Issued at 1149 PM CDT Mon May 6 2024

Widespread MVFR ceilings have been spreading inland this evening, and
this trend should continue overnight and on into early in the morning.
Areas of IFR ceilings along with patchy fog are possible too. Winds
will start out SW in the morning then become S to SE in the afternoon.
Expecting to see low end VFR ceilings in the afternoon followed by
lowering/expanding ceilings in the evening/overnight hours.

42

&&

.MARINE...
Issued at 246 PM CDT Mon May 6 2024

Light to occasionally moderate onshore flow will continue through
midweek until a cold front pushes offshore late Thursday night. This
persistent onshore flow will keep seas in the 3 to 5 ft range and
may occasionally reach 6 ft in the farshore waters. Another
consequence of the moderate onshore flow is elevated rip current
risks. Dangerous rip currents can be expected along all Gulf facing
beaches through midweek. We`re also monitoring for the potential of
coastal flooding along Gulf-facing beaches around midweek during
times of high tide. A cold front pushes offshore on late Thursday
night bringing a period of northeasterly winds that prevail into the
weekend. Showers/storms are expected to make a return over the
weekend, especially Sunday, as the next system arrives.

Mariners should note that high flows from area rivers, creeks, and
streams will lead to above normal water levels and strong currents
in the bays and ICWW well into midweek and can make navigation
difficult.

Batiste

&&

.HYDROLOGY...
Issued at 246 PM CDT Mon May 6 2024

Although there are periodic chances for scattered showers/storms
this week, this is not expected to result in any additional
flooding. Rivers will remain swollen for days (possibly weeks).
Do NOT go around barricades and stay out of the floodwaters.
Do NOT return to homes until officials deem that it is safe.

Minor to major river flooding continues for parts of Southeast
Texas, particularly along portions of the Trinity, San Jacinto, and
Navasota rivers. The following river points are either at or
forecast to go into Major flood stage as of Monday afternoon:

- Trinity River (Liberty): Major Flood Stage
- Trinity River (Goodrich): Major Flood Stage
- Trinity River (Moss Bluff): Major Flood Stage
- West Fork San Jacinto (Humble): Major Flood Stage
- Navasota River (Normangee): Moderate to Major Flood Stage

Remember to heed any instructions from your local officials and to
never travel through 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 flood threat continues.

Also of note is that the downstream runoff from the previous
rainfall will cause continued rises along the Brazos River through
the end of the week. The Brazos River at Sugar Land, Rosharon, and
West Columbia are forecast to rise into minor flood stage at the end
of the work week and through the weekend.

Batiste

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL)  74  90  73  91 /   0   0   0  10
Houston (IAH)  75  90  75  91 /   0   0   0   0
Galveston (GLS)  76  82  76  84 /   0   0   0   0

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...High Rip Current Risk through Tuesday evening for TXZ436>439.

GM...None.
&&

$$