Hurricane Nicholas

[WxWatcher007]

The odds for tropical development in the Bay of Campeche and western Gulf of Mexico has continued to increase, and the NHC has designated the disturbance currently over southern Mexico as Invest 94L. 

This one will need to be watched as it traverses the historically favorable BoC and skirts northward along a ridge toward the western Gulf. Shear and land proximity look like potential limiting factors, but 1) this is likely to be a significant rain maker in TX/LA, and 2) If land interaction is reduced early on it could intensify at a faster rate. 

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 AM EDT Sat Sep 11 2021

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

The National Hurricane Center is issuing advisories on Hurricane 
Larry, located over the Labrador Sea. 

A tropical wave and an upper-level trough are producing a large area 
of disorganized showers and thunderstorms over portions of Central 
America, southeastern Mexico, and the adjacent waters of the 
northwestern Caribbean Sea and southern Gulf of Mexico.  Although 
upper-level winds are not conducive for development currently, they 
are expected to become more favorable for the system during the next 
day or so. A tropical depression is likely to form on Sunday or 
Monday while the disturbance moves northwestward and then northward 
near the coast of northeastern Mexico.  Further development will be 
possible through the middle of next week if it remains over water, 
and interests along the western and northwestern Gulf coast should 
monitor the progress of this system. 

1. Regardless of development, this disturbance is expected to produce 
heavy rain across portions of Central America and the Yucatan 
Peninsula through today which may lead to flash flooding and 
mudslides. By late this weekend, heavy rain will likely reach 
portions of the western Gulf coast, including coastal Texas and 
Louisiana through the middle of next week. Localized significant 
rainfall amounts will be possible, potentially resulting in areas of 
flash and urban flooding.
* Formation chance through 48 hours...high...70 percent.
* Formation chance through 5 days...high...80 percent.

 

[MattPetrulli]

While 12z GFS and ensembles are stronger with 94L, something that may hold it back besides land interaction would be dry air as multiple GFS runs have been hinting at

[WxWatcher007]

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 PM EDT Sat Sep 11 2021

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

The National Hurricane Center has issued the last advisory on 
Post-Tropical Cyclone Larry, located over the Labrador Sea. 

A tropical wave and an upper-level trough continue to produce a 
large area of disorganized showers and thunderstorms over portions 
of southeastern Mexico and the southern and central Gulf of Mexico. 
Although upper-level winds are not conducive for development 
currently, they are expected to become more favorable for the system 
during the next day or so. A tropical depression is likely to form 
on Sunday or Monday while the disturbance moves northwestward and 
then northward near the coast of northeastern Mexico.  Further 
development will be possible through the middle of next week if it 
remains over water, and interests along the western and northwestern 
Gulf coast should monitor the progress of this system.  An Air Force 
Hurricane Hunter aircraft is scheduled to investigate the system 
tomorrow.

1. Regardless of development, this disturbance is expected to produce 
heavy rain across portions of Central America and the Yucatan 
Peninsula through today which may lead to flash flooding and 
mudslides. By late this weekend, heavy rain will likely reach 
portions of the western Gulf coast, including coastal Texas and 
Louisiana through the middle of next week. Localized significant 
rainfall amounts will be possible, potentially resulting in areas of 
flash and urban flooding.
* Formation chance through 48 hours...high...80 percent.
* Formation chance through 5 days...high...90 percent.

[MattPetrulli]

Euro coming in with a landfall in mid TX coast Tuesday morning. Models seem to be zeroing in on a US landfall but nothing for sure yet. 

[Ed, snow and hurricane fan]

Looking at the Tropical Tidbits loop (Gulf, 94L centered jumps around), and wonder where the center forms, if it does.  Modelling on Ida shifted completely once the models had an actual center to work with.  Centers forms a bit E of where expected, land interaction is suddenly less and more time over water on the way to Louisiana.  Not an amateur forecast, just speculation. 

[WxWatcher007]

Recon heading toward the system now. They’re not wasting any time with this one. 

[WxWatcher007]

Recon has entered the invest. Looking for evidence of a well defined LLC. Some FL and SFMR readings are already over 34kts. 

[eyewall]

PTC 14 at 11am

[yoda]

15 minutes ago, eyewall said:

PTC 14 at 11am

TS Nicholas 

[yoda]

Tropical Storm Nicholas Advisory Number   1
NWS National Hurricane Center Miami FL       AL142021
1000 AM CDT Sun Sep 12 2021

...TROPICAL STORM NICHOLAS FORMS IN THE SOUTHWESTERN GULF OF
MEXICO...
...TROPICAL STORM WARNINGS AND WATCHES ISSUED FOR THE COASTS OF
NORTHEASTERN MEXICO AND TEXAS...


SUMMARY OF 1000 AM CDT...1500 UTC...INFORMATION
-----------------------------------------------
LOCATION...20.5N 94.8W
ABOUT 130 MI...205 KM NE OF VERACRUZ MEXICO
ABOUT 405 MI...650 KM SSE OF MOUTH OF THE RIO GRANDE
MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H
PRESENT MOVEMENT...NNW OR 330 DEGREES AT 13 MPH...20 KM/H
MINIMUM CENTRAL PRESSURE...1008 MB...29.77 INCHES


WATCHES AND WARNINGS
--------------------
CHANGES 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.

[yoda]

Tropical Storm Nicholas Discussion Number   1
NWS National Hurricane Center Miami FL       AL142021
1000 AM CDT Sun Sep 12 2021

Showers and thunderstorms associated with a broad area of low 
pressure over the southern Bay of Campeche have increased overnight 
and very recently become better organized with a loose band of 
convection around the northeastern portion of the circulation. An 
Air Force Reserve reconnaissance aircraft that has been 
investigating the system has found 44-kt flight-level winds and 
SFMR winds that support a 35-kt initial intensity.  Based on the 
recent increase in organization and the 35-kt initial intensity, 
advisories are being initiated on Tropical Storm Nicholas, the 
fourteenth named storm of the Atlantic hurricane season. 

The storm is located within an environment of moderate 
south-southwesterly vertical wind shear, over warm waters, and in a 
moist and unstable atmosphere. These conditions should allow gradual 
strengthening over the next 24 to 48 hours.  The NHC intensity 
forecast follows suit and calls for gradual strengthening until 
the system reaches the coast of Texas.  The official wind speed 
forecast is near the higher end of the guidance in best agreement 
with the SHIPS statistical guidance, the HFIP corrected consensus, 
and the HWRF.  In this case, the intensity forecast is highly 
dependent on eventual track of the system.  A track to the east of 
the NHC forecast could result in a lower wind shear environment 
and slightly more time over water for the system to strengthen.  
Conversely a track to the west of the forecast track would result 
in the system interacting with land much sooner. 

Since the system is still in its formative stage the initial motion 
estimate is a somewhat uncertain 330/11 kt.  A north-northwestward 
motion around the western portion of a mid-level ridge that is 
sliding east near the coast of the Carolinas, should continue to 
steer Nicholas in that direction for the next 24 to 48 hours.  
After that time, steering currents weaken and the cyclone is 
expected to move slowly north-northeastward between a couple of 
mid-level ridges located to the east and west of Nicholas.  The 
track guidance generally agrees with this overall scenario but 
there is some cross-track spread with the UKMET along the left side 
of the guidance envelope taking the storm into northeastern Mexico, 
while the GFS, HWRF, and HMON are along the right side.  The NHC 
track is near the various consensus models and both the EC and GFS 
ensemble means.

Key Messages:

1. Tropical storm conditions are expected along portions of the 
northeastern coast of Mexico and the coast of south Texas 
beginning on Monday.  Nicholas is forecast to approach the middle 
Texas coast as a strong tropical storm on Tuesday, and tropical 
storm conditions are possible along portions of the middle and upper 
Texas coasts late Monday night and Tuesday. 

2. There is the possibility of life-threatening storm surge along 
the coast of Texas from the Mouth of the Rio Grande to High Island. 
Residents in these areas should follow any advice given by local 
officials. 

3.  Periods of heavy rainfall are expected to impact portions of the 
Texas and Louisiana coasts today through the middle of the week. 
Significant rainfall amounts are possible, potentially resulting in 
areas of flash, urban, and isolated river flooding.


FORECAST POSITIONS AND MAX WINDS

INIT  12/1500Z 20.5N  94.8W   35 KT  40 MPH
 12H  13/0000Z 21.9N  95.7W   40 KT  45 MPH
 24H  13/1200Z 24.1N  96.6W   45 KT  50 MPH
 36H  14/0000Z 26.4N  96.9W   50 KT  60 MPH
 48H  14/1200Z 28.2N  96.5W   55 KT  65 MPH
 60H  15/0000Z 29.4N  95.9W   40 KT  45 MPH...INLAND
 72H  15/1200Z 30.3N  95.2W   30 KT  35 MPH...INLAND
 96H  16/1200Z 31.0N  94.8W   25 KT  30 MPH...INLAND
120H  17/1200Z 32.0N  94.5W   20 KT  25 MPH...POST-TROP/REMNT LOW

$$
Forecaster Brown

[yoda]

[yoda]

[Windspeed]

Looking for if/when it can develop a core. If a core does develop with enough lead time prior to land interaction or an increase in westerly 300 hPa flow, then we have a shot at getting Hurricane Nicholas. If the system struggles to develop a core, then it likely follows forecast guidance for intensity closely. That's the uncertainty that the TC models will struggle with, with respect to intensity, for at least the next 24 hours.

[Ed, snow and hurricane fan]

Watched Dr. Cowans video, shear should keep this from doing, at best, minimal Cat 1 winds.  But TCs w/o big winds (here in Houston) like Harvey, Imelda and Beta have caused issues.  GFS wouldn't be as bad as any of those, but might cancel school Tuesday.  No snow days down here (we had a week of icy, cold and rolling blackout days in February), so it is usually rain days, and the three named storms all cancelled at least a day of school, Harvey, 2 full weeks/10 days.  As did Ike, but I was an oilfield engineer then.

[eyewall]

1 hour ago, yoda said:

TS Nicholas 

yeah they took the banner down and made a last minute call. Interesting to see how that happened.

[Ed, snow and hurricane fan]

Recon seems to suggest more than 1 LLC.  I assume they'll consolidate under the storms, but it can't get too strong before it does.

[Floydbuster]

 

[Ginx snewx]

Yea not good on the Euro for rains

[MattPetrulli]

...NICHOLAS EXPECTED TO STRENGTHEN AS IT MOVES TOWARD THE NORTHWEST
GULF COAST...
...STORM SURGE WARNING AND HURRICANE WATCH ISSUED FOR A PORTION OF
THE TEXAS COAST...


SUMMARY OF 400 PM CDT...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...22.8N 95.5W
ABOUT 160 MI...260 KM ESE OF LA PESCA MEXICO
ABOUT 240 MI...385 KM SSE OF MOUTH OF THE RIO GRANDE
MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H
PRESENT MOVEMENT...NNW OR 340 DEGREES AT 14 MPH...22 KM/H
MINIMUM CENTRAL PRESSURE...1008 MB...29.77 INCHES

[Ed, snow and hurricane fan]

13 minutes ago, Ginx snewx said:

Yea not good on the Euro for rains

Jack Sillin on Twitter noted the Euro forecast PWs over 4 inches are probably not realistic, unrealistic atmospheric moisture, unrealistic QPF.  Not that 'a mere' 10 to 15 inches is a picnic.

[Ginx snewx]

2 minutes ago, Ed, snow and hurricane fan said:

Jack Sillin on Twitter noted the Euro forecast PWs over 4 inches are probably not realistic, unrealistic atmospheric moisture, unrealistic QPF.  Not that 'a mere' 10 to 15 inches is a picnic.

Well...there are always reasons why not and its only one run, but remember how everyone ignored Harvey totals. I wouldn't throw shade just yet

[yoda]

29 minutes ago, MattPetrulli said:

...NICHOLAS EXPECTED TO STRENGTHEN AS IT MOVES TOWARD THE NORTHWEST
GULF COAST...
...STORM SURGE WARNING AND HURRICANE WATCH ISSUED FOR A PORTION OF
THE TEXAS COAST...


SUMMARY OF 400 PM CDT...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...22.8N 95.5W
ABOUT 160 MI...260 KM ESE OF LA PESCA MEXICO
ABOUT 240 MI...385 KM SSE OF MOUTH OF THE RIO GRANDE
MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H
PRESENT MOVEMENT...NNW OR 340 DEGREES AT 14 MPH...22 KM/H
MINIMUM CENTRAL PRESSURE...1008 MB...29.77 INCHES

WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY:

The Tropical Storm Warning has been extended eastward to Freeport, 
Texas.

A Storm Surge Warning has been issued for the coast of Texas from
Port Aransas to San Luis Pass, including Aransas Bay, San Antonio 
Bay, and Matagorda Bay.

A Hurricane Watch has been issued for the coast of Texas from Port
Aransas to Sargent.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Storm Surge Warning is in effect for...
* Port Aransas to San Luis Pass Texas
* Aransas Bay, San Antonio Bay, and Matagorda Bay

A Hurricane Watch is in effect for...
* Port Aransas to Sargent Texas

A Tropical Storm Warning is in effect for...
* Mouth of the Rio Grande to Freeport 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

[yoda]

Tropical Storm Nicholas Discussion Number   2
NWS National Hurricane Center Miami FL       AL142021
400 PM CDT Sun Sep 12 2021

Visible satellite imagery, scatterometer wind data, and earlier
reconnaissance aircraft observations indicate that the circulation
of Nicholas is elongated from northwest to southeast.  In fact,
visible satellite imagery and the aircraft data has shown that
there have been several low-level swirls rotating about a mean
center.  This is not surprising since the tropical cyclone is
still in its formative stage.  The Air Force plane did not find
winds any stronger than they did this morning and the ASCAT data
revealed peaks winds of around 30 kt. Given the typical
undersampling of the scatterometer instrument, the earlier aircraft
data, and peak one-minute wind observations of 31 kt from NOAA buoy
42055 earlier today, the intensity remains 35 kt for this advisory.

Nicholas will be moving over the warm waters of the western Gulf of 
Mexico during the next day or so, and this combined with a moist, 
unstable atmosphere favors strengthening.  The primarily inhibiting 
factor appears to be moderate south-southwesterly vertical wind 
shear caused by an upper-level trough over northern Mexico. The 
trough is forecast to move westward and weaken during the next day 
or so, which could allow for a more favorable upper-level wind 
pattern later tonight and Monday.  The NHC intensity forecast again 
calls for strengthening while the system moves toward the northwest 
Gulf coast, but the main uncertainty regarding the intensity 
forecast is how much time the cyclone will spend over the Gulf 
waters.   The GFS and HWRF models, which depict a track farther 
east, show significantly more strengthening than the UKMET and ECMWF 
models which show a weaker tropical cyclone moving inland over 
northeastern Mexico or southern Texas much sooner. The NHC intensity 
forecast is similar to the previous advisory, but indicates a faster 
rate of strengthening during the next 12-24 hours.  Although not 
explicitly shown in the intensity forecast, Nicholas could approach 
hurricane strength when it nears the northwest Gulf coast, 
especially if it moves to the right of the NHC forecast track and 
spends more time over water. Due to this uncertainty a Hurricane 
Watch has been issued a for a portion of the Texas coast. The NHC 
forecast is in best agreement with the SHIPS and HFIP corrected 
consensus model, but is not as high as the latest HWRF.

The center of Nicholas appears to have re-formed farther north since 
this morning and the initial motion estimate is again a somewhat 
uncertain 340/12 kt. The track forecast reasoning has not changed 
from this morning.  Nicholas should move north-northwestward to 
northward during the next day or so around the western portion of a 
mid-level ridge that is located near the southeast U.S. coast.  The 
latest runs of the various dynamical models have shown typical 
variability, but the overall guidance envelope has not changed too 
much through the first 36 hours.  The GFS has been the most 
consistent model and its 12Z run was fairly close to the previous 
NHC track forecast.  Therefore, the NHC track leans along the right 
side of the guidance envelope between the HWRF and GFS, which 
are a little to the right of the consensus aids. Due to the acute 
angle of approach of Nicholas to the coast, users are reminded to 
not focus on the exact forecast track as small changes in the 
heading of the cyclone could result in differences in both the 
location and timing of landfall.  Regardless of where Nicholas makes 
landfall, storm surge, wind, and rainfall impacts are likely over a 
large portion of northeastern Mexico and Texas coastal areas.  
After landfall, a slower north-northeastward motion is forecast, and 
by 72 hours the cyclone is forecast to be located between a couple 
of mid-level ridges, which will likely result in weaker 
steering currents and an even slower northeastward motion.  By day 
5, the global model guidance suggest that the low-level circulation 
will become an open trough so dissipation is indicated at that time.

Key Messages:

1.  Periods of heavy rainfall are expected to impact portions of the 
Texas and Louisiana coasts today through the middle of the week. 
Significant rainfall amounts are possible, potentially resulting in 
areas of considerable flash and urban flooding, especially in highly 
urbanized metropolitan areas. Isolated minor to moderate river 
flooding is also expected. 

2. There is the danger of life-threatening storm surge inundation 
along the coast of Texas from Port Aransas to San Luis Pass. 
Residents in these areas should follow any advice given by 
local officials. 

3. Nicholas is forecast to approach the middle Texas coast as a 
strong tropical storm late Monday and early Tuesday, and could be 
near hurricane intensity if it moves to the right of the forecast 
track and remains over water longer. Tropical storm conditions are 
expected along portions of the middle Texas coast beginning Monday 
afternoon, with hurricane conditions possible from Port Aransas to 
Sargent late Monday and Monday night. 

4. Tropical storm conditions are expected along portions of the 
northeastern coast of Mexico and the coast of south Texas beginning 
Monday morning.   

FORECAST POSITIONS AND MAX WINDS

INIT  12/2100Z 22.8N  95.5W   35 KT  40 MPH
 12H  13/0600Z 24.4N  96.3W   45 KT  50 MPH
 24H  13/1800Z 26.7N  96.9W   55 KT  65 MPH
 36H  14/0600Z 28.7N  96.8W   55 KT  65 MPH...INLAND
 48H  14/1800Z 30.4N  96.3W   35 KT  40 MPH...INLAND
 60H  15/0600Z 31.2N  95.8W   30 KT  35 MPH...INLAND
 72H  15/1800Z 31.7N  95.2W   25 KT  30 MPH...INLAND
 96H  16/1800Z 31.9N  94.7W   20 KT  25 MPH...POST-TROP/REMNT LOW
120H  17/1800Z...DISSIPATED

$$
Forecaster Brown

[AChilders]

https://twitter.com/nwshouston/status/1437149092979871745?s=21

[Ed, snow and hurricane fan]

Recon center SW of the main convection.  1009 mb, not in a hurry to get organized.  HWRF and HMON show slow intensification, both ballpark 990 mb and 50 knots.  Decent clustering on track.

[GaWx]

IF the 18Z Euro were to closely verify, Houston would have a huge flooding problem: this shows 12-20"+ amounts right in the city with most of this within just a 48 hour period and it still raining due to a near stalled Nicholas:

 

 

[Normandy]

This would be nothing new to Houston.  These 1 and 100 year floods are no longer 1 and 100 year anymore.   This region of the country is used to flood events like this.  I’m more concerned about this over performing from a wind standpoint.  It’s generating a lot of vigorous convection which is usually a sign that over performing in intensity is a possibility

[MattPetrulli]

35 minutes ago, Normandy said:

This would be nothing new to Houston.  These 1 and 100 year floods are no longer 1 and 100 year anymore.   This region of the country is used to flood events like this.  I’m more concerned about this over performing from a wind standpoint.  It’s generating a lot of vigorous convection which is usually a sign that over performing in intensity is a possibility

I thought so earlier today, but recon and satellite show a rather very disorganized system and most intensity guidance has stayed in TS territory this evening. Could make it to a hurricane maybe, but I think it's rather unlikely at this time. Small size could help it spin up and intensify quickly, but it only has about 24-36 more hours over water at most so we'll see. 

 

[Amped]

Finally center is kinda showing up on radar. 

http://moe.met.fsu.edu/~mnissenbaum/RadarArchive/KBRO2/loop.html