August 2021: Major Hurricane Ida/SE Louisiana Landfall

[tireman4]

18
FXUS64 KHGX 121025
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
525 AM CDT Thu Aug 12 2021

.SHORT TERM [Today Through Friday Night]...
Yesterday`s heat indices didn`t pan out with drier air mixing down
and showers and thunderstorms bringing more clouds and slightly
cooler temperatures. GOES-16 imagery showing the PW have increased
across the region and over the Gulf and with the upper level shear
axis well inland and continuing to shift west will be looking for
the moisture to continue to increase slowly throughout the day.
Scattered showers over the Gulf and near the coast this morning
should spread into the southern half of the CWA through early
afternoon. Storms will be slow moving and capable of a quick 0.5"+
of rain for those that get one. Short term guidance has been doing
fairly well with trends and anticipate scattered storms through
the afternoon. Some of the HRRR runs have been pinging on an area
of storms getting somewhat organized over the Gulf waters south of
LA and propagating west into the region which could sap some of
the moisture for this afternoon...will need to watch those trends
closely this morning. Heat indices should be 100-106 today so
below advisory. Storms should dissipate by around 7 or 8 pm
followed by a relatively quiet night with mostly clear to partly
cloudy skies. Scattered storms developing again Friday and
spreading inland throughout the day becoming more isolated well
inland. CAPE will be abundant but wind profiles are weak and will
struggle with separation so expect mainly brief heavy rains and
lightning to the be the threats.

45

.LONG TERM [Saturday Through Thursday]...

To be hot, or to not be hot, that is the question. If you`ve been
anywhere in Texas over the past week or so, then you already know
the answer. If it`s your first day here, then welcome! Keep an
umbrella handy and prepare to sweat if you`re outside for more than
5 minutes. All joking aside, our typical summertime pattern of high
temperatures in the mid/upper 90s, heat index values on the edge of
Heat Advisory criteria (105-107 degrees), and a chance of scattered
showers and thunderstorms continues for Saturday. Sunday is where
things get a bit more interesting with a weak cold front attempting
to push into Texas. Moisture convergence along the boundary as it
pushes into the region on early Sunday increases PW values to 2.1"-
2.2". As a result, locally heavy rainfall will be a possibility,
especially along the boundary. Due to lingering moisture and
uncertainty on the positioning of the boundary before it washes out,
kept elevated PoPs in the grids going into Monday.
Sunday and Monday will feature slightly "cooler" temperatures as we
trade out highs in the mid/upper 90s with highs in the low/mid 90s.

The driver behind the front is a weak upper-level trough in the
Upper Midwest that will make an attempt at becoming a cutoff low
early next week. Currently leaning towards the trough slightly
deepening rather than cutting off for now. Global models are in
agreement on the trough axis deepening enough to extend into
Southeast Texas, which puts us in a more favorable position for
shortwave disturbances. Next week should feature more scattered
coverage of our usual showers/thunderstorms rather than isolated
coverage like we`ve seen recently. Next week also features a return
back to highs in the mid/upper 90s and elevated heat index values,
so enjoy the "cooler" temperatures while they last on Sunday and
Monday!

Batiste
&&

.AVIATION [06Z TAF Issuance]...
VFR for the most part though some patchy MVFR/IFR conditions will
be possible for CXO/UTS/CLL in the 09-14z time frame today and
again on Friday.

Main issue is the diurnal wx pattern with VCSH initial/early
threats then switching to VCTS for the IAH and southward
terminals today and again Friday 11-23z.
&&

.MARINE...

Light to occasionally moderate onshore flow will continue to prevail
through Friday. The pressure gradient begins to weaken going into
the weekend, so expect winds and seas to gradually decrease.
Isolated to scattered showers and thunderstorms will continue to be
a daily possibility going into next week. Mariners should monitor
the progress of Tropical Depression Fred as it is projected to move
into the eastern Gulf over the weekend.

Batiste
&&

&&

.CLIMATE...
Yet another record high minimum temperature at Hobby yesterday.
For those keeping track or just curious this makes 11 record high
mins tied or broken at Hobby since July 18th.
45

&&

.PRELIMINARY POINT TEMPS/POPS...

College Station (CLL) 95 75 94 75 95 / 10 10 20 10 30
Houston (IAH) 93 76 93 76 96 / 40 20 30 10 40
Galveston (GLS) 90 82 90 81 91 / 30 30 40 10 40

&&

.HGX WATCHES/WARNINGS/ADVISORIES...

TX...None.
GM...None.

&&

$$


SHORT TERM...45
LONG TERM...26

[Stratton20]

95L up to a 70% chance to develop now

[Kingwood36]

Seems like another Florida storm at this moment in time

[Stratton20]

Kingwood36 probably, the only thing that I see could possibly change this track is a center relocation as right now it looks like some easterly shear is blowing most of the convection to the WSW of 95L’s center

[Cpv17]

Seems like another Florida storm at this moment in time

Even if it does go towards Florida there’s a chance it could have string ridging to it’s north forcing the storm west. Some ensembles show this option.

[cperk]

Seems like another Florida storm at this moment in time

Even if it does go towards Florida there’s a chance it could have string ridging to it’s north forcing the storm west. Some ensembles show this option.

True that Cpv17 we’ve seen that scenario many times it’s too early to say this is a Florida storm.

[Stratton20]

Im hearing a lot of chatter that La Nina may be making a return by peak hurricane season? Is this true?

[Texaspirate11]

The GFS is liking the Carolinas
Euro going west
So....its just a bunch of spaghettios now
95L

[Cpv17]

The GFS is liking the Carolinas
Euro going west
So....its just a bunch of spaghettios now
95L

The GFS is almost always right biased cuz it over does troughing and underestimates ridging.

[Texaspirate11]

The GFS is liking the Carolinas
Euro going west
So....its just a bunch of spaghettios now
95L

The GFS is almost always right biased cuz it over does troughing and underestimates ridging.

Totally agree

[DoctorMu]

Im hearing a lot of chatter that La Nina may be making a return by peak hurricane season? Is this true?

viewtopic.php?f=2&t=1091&start=740

[Scott747]

Both hurricane models on 12z bring 95l through the Caribbean on a little lower line compared to the operational models before beginning to move wnw towards Hispaniola. The experimental hurricane models show something similar as well.

So far the operational GFS hasn't budged with the high line and only a ragged vorticity in the mid range.

[Stratton20]

DoctorMuDoctorMu thanks Il take a look at it

[Scott747]

Much stronger vorticity on the 18z GFS and finally attempts to close it off on the approach to the northern part of the Leewards.

[sambucol]

Both hurricane models on 12z bring 95l through the Caribbean on a little lower line compared to the operational models before beginning to move wnw towards Hispaniola. The experimental hurricane models show something similar as well.

So far the operational GFS hasn't budged with the high line and only a ragged vorticity in the mid range.

Would that possibly put into our side of the GOM?

[Scott747]

Both hurricane models on 12z bring 95l through the Caribbean on a little lower line compared to the operational models before beginning to move wnw towards Hispaniola. The experimental hurricane models show something similar as well.

So far the operational GFS hasn't budged with the high line and only a ragged vorticity in the mid range.

Would that possibly put into our side of the GOM?

Depends on the orientation of the ridge. Even with the lower line through the Caribbean it looks like something would take a path similar to Fred.

It will be a few days before we get a handle on ridging though. If 95l does develop I suspect we would begin to have some upper level recon flights later this weekend or early next week before we can have some better confidence on any threat to the WGOM. As of now and based on modeling it appears that 95l/Grace will track somewhere along the Greater Antilles and possibly in the vicinity of the Bahamas over the next 5-7 days.

After that is a different ballgame....

[jasons2k]

No measurable rain here since July 27. Just sayin’

[Stratton20]

18z GEFS Ensemble, pretty interesting, their seems to be quite a split between the ensemble members

[Cpv17]

No measurable rain here since July 27. Just sayin’

Most of it has been south of 10. Some places have received nearly 10” in the past couple weeks.

[Cromagnum]

Nice supercell looking system went through the southwest side of the area earlier. I could see it from Rosharon easily.