August 2020:

[weatherguy425]

Critically important, folks. Model data is one thing... what is happening is more important. Stronger ridge + less Texas troughing increases risk of a further-southwest landfall verifying.

Bumping this. Hard to take track guidance too seriously if parent data they’re run from is off.

[Scott747]

6z HMON goes in around San Luis Pass as a strong 3.

[sambucol]

Laura: in light of the HMON and HWRF Latest tracks, will the cone be shifted a little more west later this morning? Does it look like the track of the storm will more likely follow a track like HMON?

[Scott747]

Critically important, folks. Model data is one thing... what is happening is more important. Stronger ridge + less Texas troughing increases risk of a further-southwest landfall verifying.

Bumping this. Hard to take track guidance too seriously if parent data they’re run from is off.

That data would show up in the 12z runs....

[Tx2005]

6z HMON goes in around San Luis Pass as a strong 3.

Pretty close to worst case for Houston.

[weatherguy425]

Critically important, folks. Model data is one thing... what is happening is more important. Stronger ridge + less Texas troughing increases risk of a further-southwest landfall verifying.

Bumping this. Hard to take track guidance too seriously if parent data they’re run from is off.

That data would show up in the 12z runs....

Ridge underestimation has been, continuously, an issue through runs leading up to this point (06z). This isn’t an underestimation just with 06Z data.

[Scott747]

Bumping this. Hard to take track guidance too seriously if parent data they’re run from is off.

That data would show up in the 12z runs....

Ridge underestimation has been, continuously, an issue through runs leading up to this point (06z). This isn’t an underestimation just with 06Z data.

But the data from the soundings he's referencing wouldn't be seen till 12z. I get that he's saying that the ridge is being underdone but I'm not sure what has been assimilated into the runs up to this point.

[weatherguy425]

That data would show up in the 12z runs....

Ridge underestimation has been, continuously, an issue through runs leading up to this point (06z). This isn’t an underestimation just with 06Z data.

But the data from the soundings he's referencing wouldn't be seen till 12z. I get that he's saying that the ridge is being underdone but I'm not sure what has been assimilated into the runs up to this point.

True! Don’t have the data in-hand, I can go back and look. But, generally speaking, there wasn’t a significant lack of ridging at that time compared to other cycles. General underestimation has been a theme. With actual obs data going in, hopefully, 12Z will be more clear as well.

[Scott747]

6z HWRF is similar to the 0z run. Just to the e of Cameron.

[weatherguy425]

6z HWRF is similar to the 0z run. Just to the e of Cameron.

Here are the 00Z & 06Z

[Scott747]

Ridge underestimation has been, continuously, an issue through runs leading up to this point (06z). This isn’t an underestimation just with 06Z data.

But the data from the soundings he's referencing wouldn't be seen till 12z. I get that he's saying that the ridge is being underdone but I'm not sure what has been assimilated into the runs up to this point.

True! Don’t have the data in-hand, I can go back and look. But, generally speaking, there wasn’t a significant lack of ridging at that time compared to other cycles. General underestimation has been a theme. With actual obs data going in, hopefully, 12Z will be more clear as well.

Used to NCEP had an update with all the soundings etc. that was being ingested into the upcoming runs. I've lost the link that used to show it publicly...

[weatherguy425]

But the data from the soundings he's referencing wouldn't be seen till 12z. I get that he's saying that the ridge is being underdone but I'm not sure what has been assimilated into the runs up to this point.

True! Don’t have the data in-hand, I can go back and look. But, generally speaking, there wasn’t a significant lack of ridging at that time compared to other cycles. General underestimation has been a theme. With actual obs data going in, hopefully, 12Z will be more clear as well.

Used to NCEP had an update with all the soundings etc. that was being ingested into the upcoming runs. I've lost the link that used to show it publicly...

Either way, not confidence boosting considering these runs had the system going just east of “us” based on modeled ridging & troughing that isn’t verifying up the this point. Underdoing ridging, overdoing troughing can have big implications.

[Tx2005]

Maybe this is a dumb question, but I’m very new to this stuff. Are models normally this far apart in track a few days out?

[Ace]

[Stormlover2020]

Euro is more west off of cuba

[Stormlover2020]

New euro aiming for Freeport or Galveston

[Cromagnum]

Had a small feeder band from Marco come over this morning. Welcome rain.

[tireman4]

Well, parts of this is out of date due to the shift in the track...humm

000
FXUS64 KHGX 240943
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
443 AM CDT Mon Aug 24 2020

.SHORT TERM [Through Tuesday]...
With low-level moisture increasing from the Gulf, scattered activity
will continue to develop and move into the coastal portions of SE TX
this morning. Coverage should become more isolated by this afternoon
across inland parts of our CWA even with Tropical Storm Marco moving
into/across southern LA today (per the slightly drier air mass wrap-
ping around into the region). From satellite/radar, Marco is still a
fairly unorganized system this morning and its impacts to SE TX will
likely remain minimal...even if it does decide to track further west.

For now, will keep the higher POPs over our eastern/coastal counties
tonight...then more evenly dispersed across the CWA tomorrow as this
system (or its remnants) head in this direction. Winds should mostly
range from 10-15 MPH today with slightly higher speeds for the coast
and areas east of I-45 today...then slightly higher tomorrow. As for
temperatures, will continue to lean warmer than guidance today as it
has been verifying. 41

&&

.LONG TERM, MARINE & TROPICAL...
At the start of the period, Laura is expected to be situated in the
central Gulf at hurricane strength. It should make steady northwest
progress then eventually take a turn to the north around the western
periphery of a high pressure area extending from the east coast.
Laura is expected to make landfall along the northwest Gulf Coast
late Wed.

The current official NHC forecast favors a track toward the
southwestern La coastline. There are always uncertainties in the
longer range forecasts, and of note eastern parts of the CWA are
within the fringes of the forecast cone. Residents across the area
should keep up with the latest forecasts and any emergency
management recommendations. Slight storm wobbles, center
reformation, and/or variations in the strength of the ridge to its
north could make considerable differences in the forecast...from
negligible impacts with a further eastward track to near hit from a
strong hurricane. Watches may be issued for portions of the Gulf Coast
later today.

Forecast confidence should generally improve after Laura moves into
the Gulf off of Cuba. The center should become better defined. In
addition, aircraft data should be able to examine and get a better
grasp the surrounding environmental conditions.

Based upon the current fcst of the system making landfall where the
4am CDT advisory depicts (to the east of our CWA) one might
generally expect:

Rainfall:
- Look for some far outer rain bands to begin moving into parts of
the area late Tue into Wed, with increasing precip coverage across
southeast and east parts of the area as Laura approaches the coast
and moves inland. Assuming current track holds close, areas
generally east of the I-45 corridor should anticipate 1-4" (west-to-
east) with higher totals in any training banding between today and
Friday. Less rain with an eastward track & more with a westward
shift.

Winds:
- Any given location generally east of I-45 has between a 40-60%
chance of experiencing tropical storm force winds. Chances
lower the further west one goes. Areas along a line from
Matagorda Bay-College Station have a 10-30% risk. Most likely
time of arrival would be during the day Wednesday offshore and
immediate coast...and Wednesday evening and night further
inland. That being said, outer rain bands arriving earlier may
produce brief intermittent wind gusts to or above 34kt.

Surge/Tides:
- Too early for specifics. Highly dependent of track/intensity.
Highest to the north and east of landfall. That said, there
appears to be a fairly decent risk of coastal flooding for most
of the upper coast, especially east of Sargent from high surf
and wave run-up regardless of surge values. Additional
surge/elevated tides would enhance overall levels. For planning
purposes, inundation could occur as early as
Wednesday...especially beaches and Gulf facing locations.

Tornadoes:
- Too early to say. Most favorable locations would be in the
northeast quadrant of the cyclone. Current fcst has us on the
less favorable western side.

Seas/marine:
- 3-5 ft swell associated with Marco today will fade tonight/Tue.
- Laura swell begins arriving during the day Wed with seas
building o 7-14 feet by sunset. Peak seas and timing are
uncertain & dependent on intensity and track. Could be much
higher with a westward shift and lower with eastward shift.

Beach:
- Favorable angle of approach will drive a higher, long period
swell to the upper coast which will produce large breaking
waves (regardless of wind direction) as the day progresses
Wednesday into Wed night.
- Expect considerable wave run-up on area beaches which in itself
could cause coastal flooding. Potentially even more significant
around times of high tide AND on top of any surge (strongly
dependent on eventual track).
- Anticipate dangerous rip currents.

Again, sensible mid-late week wx is dependent on Laura`s evolution.
Going into the weekend, we should still lie in somewhat of a
weakness aloft so would expect some sct diurnal precip & maybe some
far sw side banding from Laura`s remnants far to our ne. 47

&&

.AVIATION [12Z TAF Issuance]...
A bit more active for TAF sites south of I-10 this morning as bands
of showers (and isolated thunderstorms) move into the area from the
Gulf waters. Will keep this trend going until late this morning (15
to 16Z) when things mix out a bit more given the drier air wrapping
around Tropical Storm Marco lingering over southern LA. With a more
isolated pattern expected this afternoon, will likely keep the VCSH
and VCTS mentions out for now. NE winds around 10kts should prevail
this afternoon...perhaps slightly higher for GLS. Scattered showers
are possible once again overnight/early tomorrow for southern sites.
41

&&

.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 97 75 96 76 95 / 10 10 20 20 40
Houston (IAH) 96 78 95 78 94 / 20 10 30 20 40
Galveston (GLS) 94 81 93 82 90 / 40 20 40 60 60

&&

.HGX WATCHES/WARNINGS/ADVISORIES...

TX...None.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION until 4 PM CDT this
afternoon for the following zones: Waters from Freeport to
Matagorda Ship Channel TX from 20 to 60 NM...Waters from
High Island to Freeport TX from 20 to 60 NM.


&&

$$

[Scott747]

While the NHC isn't calling it a reformation it sure does look further s than the official track.

[sambucol]

Will the NHC adjust the track west on the next update?