September 2021: Hurricane Nicholas

[Andrew]

The latest Euro is slower overall this run with a near stall near Colombus or just southwest of there. Obviously, in this scenario, the heavy rain threat would be amplified and is something we need to continue to monitor but remains an outlier at this point.

[Cpv17]

The latest Euro is slower overall this run with a near stall near Colombus or just southwest of there. Obviously, in this scenario, the heavy rain threat would be amplified and is something we need to continue to monitor but remains an outlier at this point.

Andrew, some of the ensembles the past few days and even some Euro op runs have had it stalling out.

[Andrew]

The latest Euro is slower overall this run with a near stall near Colombus or just southwest of there. Obviously, in this scenario, the heavy rain threat would be amplified and is something we need to continue to monitor but remains an outlier at this point.

Andrew, some of the ensembles the past few days and even some Euro op runs have had it stalling out.

Yea some of the Euro runs have been slower but this run was more dramatic and extreme. It's painting some areas seeing 20-30 inches which is a pretty large departure from most other models.

[Stormlover2020]

And some gfs members and gfs runs have showers stalls

[Scott747]

Recon has already departed and getting out there a little earlier than I realized. I don't think it's a definitive depression/storm yet but might be enough there that they go ahead with PTC advisories at 10.

[Andrew]

Recon has already departed and getting out there a little earlier than I realized. I don't think it's a definitive depression/storm yet but might be enough there that they go ahead with PTC advisories at 10.

I believe there is enough model support and now that convection/vorticity has entered the BOC a PTC will be issued either way this morning or by early afternoon. Watches (and warnings) for tropical storm conditions need to be issued along the Texas and Mexico coastline so people can make the necessary preparations. I think the biggest question will likely be if recon can find enough to support an immediate upgrade to a TD. Based on the latest satellite and surface data I suspect they won't but we will see. Interesting to note the GFS remains steady on a storm hugging the coast while the ensembles and every other model have landfall in the Southern/Middle part of the Texas Coast.

[Scott747]

6z HWRF finally initialized correctly instead of over in the EPAC.

Brings a cat 1 just n of Rockport on Tuesday morning after brushing just offshore of Corpus.

6z HMON brings a moderate ts over Freeport/Surfside early Tuesday afternoon.

To be fair we could have a refresh with a new initialization point for the 12z runs based on what recon finds.

[Andrew]

6z HWRF finally initialized correctly instead of over in the EPAC.

Brings a cat 1 just n of Rockport on Tuesday morning after brushing just offshore of Corpus.

6z HMON brings a moderate ts over Freeport/Surfside early Tuesday afternoon.

To be fair we could have a refresh with a new initialization point for the 12z runs based on what recon finds.

Check out all the dry air being ingested into the system from both models once it makes it inland. This system could really dry up/dissipate quickly depending on the track

[Scott747]

6z HWRF finally initialized correctly instead of over in the EPAC.

Brings a cat 1 just n of Rockport on Tuesday morning after brushing just offshore of Corpus.

6z HMON brings a moderate ts over Freeport/Surfside early Tuesday afternoon.

To be fair we could have a refresh with a new initialization point for the 12z runs based on what recon finds.

Check out all the dry air being ingested into the system from both models once it makes it inland. This system could really dry up/dissipate quickly depending on the track

Yeah it's a pretty steep drop off. Does appear it will have a window of favorable conditions to strengthen up to about 28n and then it's downhill from there unless it tracks like the GFS is showing and buying it about 12-18 more hrs before shear hits it.

[Scott747]

Decent obs so far with recon. If they can close it off it will likely go straight to a ts. Pressure so far is around 1010...

[Kingwood36]

Still need that circulation tho

[davidiowx]

Still need that circulation tho

Yep, fairly steady pressure and TS winds around (at flight level). No LLC yet

[tireman4]

000
FXUS64 KHGX 121123
AFDHGX

Area Forecast Discussion
National Weather Service Houston/Galveston TX
623 AM CDT Sun Sep 12 2021

...Potentially significant heavy rain event shaping up for those
closer to the coast...

...Monitoring the Gulf for possible impacts early next week...

.AVIATION [12Z TAF Issuance]...

Starting off the day with VFR conditions and light and variable
winds at area sites. As rain moves in from the Gulf throughout the
day and into the overnight hours, conditions begin to deteriorate.
Rain moves into the coastal sites (LBX and GLS) in the morning
hours and reaches inland sites in the afternoon/evening hours.
Latest run of the CAMs indicate that CLL and UTS will remain north
of the widespread rain, at least for this TAF period, so these
sites do not have any mention of VCSH/VCTS. MVFR ceilings move in
for central and southern sites (IAH and southward) after sunset.
For CXO, UTS, and CLL, MVFR ceilings make their way in on early
Monday morning. Hi-res models are hinting at IFR ceilings for most
locations on Monday morning as a band of rain moves into the
area. A little early to commit to that, so settled for a hint with
SCT010 to coincide with the prevailing SHRA.

Batiste

&&

.PREV DISCUSSION /Issued 500 AM CDT Sun Sep 12 2021/...

.SHORT TERM [Through Monday Night]...
Today marks the beginning of quite a dreary and rainy pattern.
Satellite-derived total PW reveals moisture moving in from the Gulf
early this morning with PW values already in 1.6"-1.8" range in the
western Gulf waters. Models are still in agreement on a large plume
of Gulf moisture moving in from the southeast this afternoon. PW
values by Sunday night will reach well over 2" for locations south
of and including Harris County with PW values near 2.5" closer to
the coast. Moisture will converge along a surface trough located
along the coast, so this is where most of the rainfall is expected
for today. The 00z run of the CAMs show a large swath of rain
moving ashore on Sunday afternoon with the main focus being right
along the coast that coincides with the location of the surface
trough. This is in line with the trends of the 00z run of the
global models as well.

The GFS, Canadian, and TTU-WRF are still hinting at a jet streak
developing over the CWA that would provide upper-level support for
the widespread rainfall, but the intensity of this is still a bit
uncertain with the Canadian being the strongest out of the three
solutions. Our saving grace initially is that we have been dry as of
late, so the soils will be able to handle the initial rounds of
rainfall (outside of any 3-4+" per hour rain rates). WPC currently
has areas south of a line from Columbus to Conroe to Livingston
outlined in a marginal risk for excessive rainfall with the counties
of Brazoria, Galveston, and Chambers in a slight risk for tomorrow.
The influx of tropical moisture will also bring below normal
temperatures with highs in the upper 80s/low 90s today and mid to
upper 80s on Monday. Overnight lows will be on the mild side in the
low to mid 70s.

Although this surge of moisture initially comes in on Sunday
afternoon, it is associated with Invest 94L in the Bay of Campeche.
NHC has given this disturbance a 90% chance of developing, which
lines up with the latest run of models that all agree that some
sort of low-level circulation will develop in the southwestern
Gulf. NHC is anticipating that a tropical depression is likely to
form as early as today. The track remains a bit uncertain as some
models push it inland over Eastern Mexico/South Texas and others
keep it offshore which would give it time to intensify. Either
way, we can expect numerous rounds of rainfall with the potential
for flooding where heavy rain bands (rain rates 3-4" per hour) set
up.

Through Monday night, anticipating rainfall totals south of
I-10 and along the coast of 3 to 5 inches with localized MUCH higher
amounts possible. HREF PMM shows some pockets double that closer
to the immediate coast and offshore. Last 2 runs of the TTU WRF
even higher. Whether that pans out or not, it shows the overall
potential seriousness of the situation. The slight risk of
excessive rainfall expands a bit further north for Monday to
include essentially the entire southern half of the CWA. A Flash
Flood Watch may be necessary by Monday for portions of Southeast
Texas as the heavy rainfall threat persists.

Batiste

&&

.LONG TERM, TROPICS & MARINE [Tuesday Through Sunday]...
Potential for significant rains and flooding continues. The
forecast is highly dependent on the evolution of the area of
disturbed wx currently in the Bay of Campeche. Scatterometer
sample late last night showed no closed circulation yet...just an
elongated trof axis across the western Gulf. That said, guidance
does support some organization with time and a depression could
form later today or tonight. Tropical related watches/warnings may
be hoisted for portions of the Texas coast at some point today.

Track/intensity/timing/finer details all depend on location of
of any development, and the eventual level of organization.
General steering flow into early parts of the week will be to the
north...meaning toward the Tx coast.

For planning purposes, it wouldn`t be unreasonable to coastal
residents to prepare for tropical storm (and maybe even a strong
one) situated somewhere in the vicinity of the upper coast heading
into Tues.

Rainfall:
- Again, dependent on level of organization/location of the
system. A weaker, elongated trof axis to our west will allow a
fetch of deep Gulf moisture flowing into the region. A
strengthening system offshore would tend shrink the precip field
a bit closer to the center for a while until it makes its way
closer & landfall. Until there`s more clarity...the ongoing
7-day QPF numbers have remained about the same with the highest
numbers of 10-15+ inches near the coast and less so further
inland and northwest.

Flooding:
- Some southern locations will probably have seen some substantial
rainfall by early Tues and saturated grounds. Where this
happens, additional rain will runoff and quickly produce
additional flooding.
- Training heavy bands that produce rain rates of 2-3"+ per hour
will cause issues regardless the location...especially metro
areas.

Rivers:
- Need to keep a closer eye on the southern watersheds where some
of the heavier totals are forecast. San Bernard, Tres Palacios,
Lavaca, etc. Houston area bayous and creeks may, or may not,
become a concern depending on where the heaviest rain sets up -
but are not totally immune to potential issues.

Winds:
- Too early to say. For planning purposes, those along the coast
might want to begin preparing for tropical storm storm force
winds as we head closer toward Tuesday until things hopefully
become more clear cut and the forecast refined.
- For marine interests, winds should be in the 15-20kt range
through the day Monday. Sustained 20kt winds will probably
arrive in the nearshore waters Mon evening/night. Highly
uncertain if sustained 30kt+ winds will develop or when they`ll
arrive. Maybe some frequent gusts to around that late Mon night
& Tues. At this point, best to just watch the forecast.

Seas:
- 3 to 5 foot seas will build into early-midweek.
- Expect 6 foot seas to arrive in the nearshore waters Mon
morning.
- Peak seas maybe in the 10-15ft range sometime Tues depending on
what evolves.
- Seas fall below 6 feet nearshore Wed morning.

Coastal flooding/surge/rip currents:
- Tides are already around 1 foot above normal.
- Total observed levels will probably approach the 3.0-3.5 range
at high tide tonight - below coastal flood criteria.
- Concerns grow Monday night and Tues as levels further rise.
Coastal flooding is a decent possibility at that time, though
overall severity is highly uncertain at this point.
- Surge height...way too early to know...especially considering
nothing has organized at this point.
- High risk of rip currents along area beaches today into midweek.


Forecast beyond Wednesday is highly uncertain and just loaded NBM
in the grids which advertises scattered activity into the
weekend. There are some deterministic solutions out there that
begin to dry things out somewhat during the second half of the
week but confidence is too low to weight any one solution over
another. 47

&&

.PRELIMINARY POINT TEMPS/POPS...

College Station (CLL) 92 73 86 72 85 / 10 20 70 30 50
Houston (IAH) 90 74 85 74 84 / 50 60 80 50 70
Galveston (GLS) 85 78 88 80 85 / 70 80 90 70 90

&&

.HGX WATCHES/WARNINGS/ADVISORIES...

TX...High Rip Current Risk through Wednesday morning for the
following zones: Bolivar Peninsula...Brazoria
Islands...Galveston Island...Matagorda Islands.

GM...SMALL CRAFT SHOULD EXERCISE CAUTION until 4 PM CDT this
afternoon for the following zones: Coastal waters from
Freeport to Matagorda Ship Channel TX out 20 NM...Coastal
waters from High Island to Freeport TX out 20 NM...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.

&&

$$

[Kingwood36]

I don't think it will be upgraded at this time..maybe tonight or tomorrow

[Goomba]

AL142021 - Tropical Depression FOURTEEN
Synoptic Time Latitude Longitude Intensity
2021-09-12 12:00 19.9 -94.4 30

http://rammb-data.cira.colostate.edu/tc ... r=al142021

[don]

Yep we have PTC 14 now.

NHC will initiate advisories on Potential Tropical Cyclone Fourteen, located over the southwestern Gulf of Mexico, at 1000 AM CDT (1500 UTC).

[davidiowx]

Advisories coming in 45 minutes

[don]

6Z EURO is the strongest run its had so far on this storm.

[don]

From Wxman57 this morning

Still looks like a moderate TS moving inland between Brownsville & Matagorda Bay Monday afternoon to Tuesday morning. GFS & EC indicate 30-40 kt westerly winds aloft across the upper TX coast and northern Gulf. The stronger it gets, the farther east it tracks but the more shear it encounters. If it stays weaker, then it tracks inland closer to Brownsville. Since it will be moving parallel to the coast, a minor track change means a significantly different point of landfall. Hoping to get some rain for my dry yard here in Houston. Could see 5-10".

[don]

They went straight to Tropical Storm Nicholas. Looks like they have it getting to 65mph right now.

TROPICAL STORM NICHOLAS FORECAST/ADVISORY NUMBER 1
NWS NATIONAL HURRICANE CENTER MIAMI FL AL142021
1500 UTC SUN SEP 12 2021

CHANGES IN WATCHES AND WARNINGS WITH THIS ADVISORY...

A TROPICAL STORM WARNING IS IN EFFECT FOR THE COAST OF TEXAS FROM
THE MOUTH OF THE RIO GRANDE TO PORT ARANSAS.

THE GOVERNMENT OF MEXICO HAS ISSUED A TROPICAL STORM WARNING FROM
BARRA EL MEZQUITAL NORTHWARD TO THE U.S./MEXICO BORDER.

A STORM SURGE WATCH IS IN EFFECT FOR THE COAST OF TEXAS FROM THE
MOUTH OF THE RIO GRANDE TO HIGH ISLAND.

A TROPICAL STORM WATCH IS IN EFFECT FOR THE COAST OF TEXAS FROM
NORTH OF PORT ARANSAS TO HIGH ISLAND.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT...

A TROPICAL STORM WARNING IS IN EFFECT FOR...
* MOUTH OF THE RIO GRANDE TO PORT ARANSAS TEXAS
* BARRA EL MEZQUITAL TO THE U.S./MEXICO BORDER

A STORM SURGE WATCH IS IN EFFECT FOR...
* MOUTH OF THE RIO GRANDE TO HIGH ISLAND TEXAS

A TROPICAL STORM WATCH IS IN EFFECT FOR...
* NORTH OF PORT ARANSAS TO HIGH ISLAND TEXAS

A TROPICAL STORM WARNING MEANS THAT TROPICAL STORM CONDITIONS ARE
EXPECTED SOMEWHERE WITHIN THE WARNING AREA WITHIN 36 HOURS.

A STORM SURGE WATCH MEANS THERE IS A POSSIBILITY OF
LIFE-THREATENING INUNDATION...FROM RISING WATER MOVING INLAND FROM
THE COASTLINE...IN THE INDICATED LOCATIONS DURING THE NEXT 48
HOURS. FOR A DEPICTION OF AREAS AT RISK...PLEASE SEE THE NATIONAL
WEATHER SERVICE STORM SURGE WATCH/WARNING GRAPHIC...AVAILABLE AT
HURRICANES.GOV.

A TROPICAL STORM WATCH MEANS THAT TROPICAL STORM CONDITIONS ARE
POSSIBLE WITHIN THE WATCH AREA...GENERALLY WITHIN 48 HOURS.

INTERESTS ELSEWHERE ALONG THE UPPER TEXAS COAST SHOULD MONITOR THE
PROGRESS OF THIS SYSTEM.

TROPICAL STORM CENTER LOCATED NEAR 20.5N 94.8W AT 12/1500Z
POSITION ACCURATE WITHIN 25 NM

PRESENT MOVEMENT TOWARD THE NORTH-NORTHWEST OR 330 DEGREES AT 11 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 1008 MB
MAX SUSTAINED WINDS 35 KT WITH GUSTS TO 45 KT.
34 KT....... 90NE 0SE 0SW 0NW.
WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL
MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.

REPEAT...CENTER LOCATED NEAR 20.5N 94.8W AT 12/1500Z
AT 12/1200Z CENTER WAS LOCATED NEAR 19.9N 94.4W

FORECAST VALID 13/0000Z 21.9N 95.7W
MAX WIND 40 KT...GUSTS 50 KT.
34 KT... 80NE 30SE 0SW 0NW.

FORECAST VALID 13/1200Z 24.1N 96.6W
MAX WIND 45 KT...GUSTS 55 KT.
34 KT... 70NE 40SE 0SW 0NW.

FORECAST VALID 14/0000Z 26.4N 96.9W
MAX WIND 50 KT...GUSTS 60 KT.
50 KT... 30NE 20SE 0SW 0NW.
34 KT... 70NE 50SE 20SW 30NW.

FORECAST VALID 14/1200Z 28.2N 96.5W
MAX WIND 55 KT...GUSTS 65 KT.
50 KT... 30NE 30SE 0SW 0NW.
34 KT... 70NE 60SE 30SW 30NW.

FORECAST VALID 15/0000Z 29.4N 95.9W...INLAND
MAX WIND 40 KT...GUSTS 50 KT.
34 KT... 50NE 60SE 0SW 0NW.

FORECAST VALID 15/1200Z 30.3N 95.2W...INLAND
MAX WIND 30 KT...GUSTS 40 KT.

EXTENDED OUTLOOK. NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 150 NM
ON DAY 4 AND 175 NM ON DAY 5...AND FOR INTENSITY NEAR 15 KT EACH DAY

OUTLOOK VALID 16/1200Z 31.0N 94.8W...INLAND
MAX WIND 25 KT...GUSTS 35 KT.

OUTLOOK VALID 17/1200Z 32.0N 94.5W...POST-TROP/REMNT LOW
MAX WIND 20 KT...GUSTS 30 KT.

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 20.5N 94.8W

INTERMEDIATE PUBLIC ADVISORY...WTNT34 KNHC/MIATCPAT4...AT 12/1800Z

NEXT ADVISORY AT 12/2100Z

$$
FORECASTER BROWN