EPAC: NORMA - Remnants - Discussion

[Hurricane2022]

Major Hurricane Norma continues to intensify

[Yellow Evan]

Eye warming and at least some convection trying to wrap around. May be back to around 950 mbar or so.

[Sciencerocks]

[Yellow Evan]

Hurricane Norma Discussion Number 14
NWS National Hurricane Center Miami FL EP172023
900 PM MDT Fri Oct 20 2023

Norma's satellite depiction has not changed much over the past few
hours, with a tight inner core on infrared imagery. A recent SSMI/S
microwave pass at 2306 UTC confirmed the tight core is well intact.
The last few visible satellite images showed the eye feature
becoming less cloud filled, and better defined. Earlier Air Force
Hurricane Hunters flight-level and SFMR winds supported an intensity
of 105 kt. Subject and objective Dvorak satellite intensity
estimates for this cycle range from 90 to 105 kt. Given the
satellite imagery and the earlier hurricane hunter data, will remain
near the high end of the intensity estimates, with an initial
intensity remaining at 105 kt for this advisory. The outer rain
bands of Norma are spreading over the southern portions of the Baja
California Sur peninsula.

The hurricane is move north-northwestward with an initial motion of
340/8 kt. Norma is expected to turn from a north-northwest motion
to northward over the next day or so, while it moves between a mid-
to upper-level trough to its northwest and a mid-level ridge to its
east. This will bring the center of Norma over the southern tip of
Baja California Sur within the hurricane warning on Saturday. The
track models are in fairly good agreement with little change to the
previous NHC track in the short term. After moving over the Baja
Peninsula and emerging into the Gulf of California, models are in
agreement with a northeast to east-northeastward turn towards the
coast of Sinaloa. There remains some along-track speed differences
between the various model aids. The NHC forecast is similar to the
previous, with a slight nudge to the right towards the HCCA
corrected consensus.

Norma has been able to maintain an inner core and fend off the
increasing southerly wind shear and drier air today. The drier air
has attempted to penetrate the inner core, but so far has not been
able to do so. The NHC intensity forecast is similar to the
previous, which still shows some weakening, but Norma is expected to
be a dangerous hurricane as it moves over the Baja California Sur
peninsula. Land interaction with the Baja California peninsula,
along with increasingly dry air and southerly shear, should result
in steady weakening through early next week while Norma approaches
the west coast of mainland Mexico. After the system moves inland
along the coast of Sinaloa on Monday, the system should rapidly
weaken and dissipate over the higher terrain.


Key Messages:

1. Norma is expected to bring life-threatening hurricane conditions
and a dangerous storm surge to portions of the far southern Baja
California peninsula within the hurricane warning area on Saturday.
Preparations to protect life and property should be rushed to
completion.

2. Heavy rains from Norma will begin to impact the far southern
portions of Baja California Sur tonight, continuing through
Sunday, with heavy rains reaching Sinaloa on Saturday. This
rainfall will produce flash and urban flooding, along with possible
mudslides in areas of higher terrain.

3. Norma is forecast to approach the west coast of Mexico as a
tropical storm on Sunday and Sunday night, and a Tropical Storm
Watch is in effect for a portion of that area.


FORECAST POSITIONS AND MAX WINDS

INIT 21/0300Z 20.8N 109.9W 105 KT 120 MPH
12H 21/1200Z 21.9N 110.1W 100 KT 115 MPH
24H 22/0000Z 23.0N 109.9W 85 KT 100 MPH...INLAND
36H 22/1200Z 23.6N 109.4W 70 KT 80 MPH...OVER WATER
48H 23/0000Z 23.9N 108.6W 60 KT 70 MPH
60H 23/1200Z 24.3N 107.6W 50 KT 60 MPH
72H 24/0000Z 24.8N 106.5W 30 KT 35 MPH...INLAND
96H 25/0000Z...DISSIPATED

$$
Forecaster Kelly

[Sciencerocks]

[Sciencerocks]

Hurricane Norma Discussion Number 16
NWS National Hurricane Center Miami FL EP172023
900 AM MDT Sat Oct 21 2023

Radar data from Los Cabos, Mexico, show the center of Norma is
situated just west-southwest of Cabo San Lucas this morning. Surface
observations indicate that hurricane and tropical storm conditions
are spreading over southern portions of Baja California Sur within
the warning areas. Earlier passive microwave images and recent radar
data indicate convection in the southern portion of Norma's inner
core has eroded. The hurricane is also vertically tilted due to
southerly shear, with the low-level center displaced slightly south
of the mid-level center. These structural changes suggest weakening
has occurred, which is consistent with the latest subjective and
objective intensity estimates from TAFB, SAB, and UW-CIMSS. Based on
the blend of those estimates, the initial intensity is lowered to 85
kt for this advisory.

Norma is moving just west of due north (355/7 kt) this morning. The
hurricane is expected to make landfall in the hurricane warning area
this afternoon, cross the southern portion of Baja California Sur
tonight, and emerge over the southern Gulf of California on Sunday.
Then, the weakening cyclone should turn toward the northeast and
east-northeast and slowly approach the coast of Sinaloa in western
Mexico on Sunday night into early Monday. The updated NHC track
forecast shows a slightly more gradual turn in the near term and
lies slightly west of the previous one. Norma is forecast to move
inland by early Monday and dissipate over the rugged terrain of
western Mexico by Tuesday.

Less favorable environmental conditions (increasing southwesterly
shear and reduced mid-level moisture) and land interaction with the
Baja California peninsula should cause Norma to continue weakening
during the next couple of days. This is consistent with the
deteriorating satellite structure of Norma and supported by all of
the latest dynamical and statistical guidance. The updated NHC
forecast is lower than the previous advisory, following the
multi-model consensus trends, but lies on the higher end of the
guidance envelope. Norma is still forecast to reach the west coast
of Mexico by early Monday as a tropical storm.


Key Messages:

1. Norma is expected to bring life-threatening hurricane conditions
and a dangerous storm surge to portions of the far southern Baja
California peninsula within the hurricane warning area today and
tonight.

2. Heavy rains from Norma will continue to impact southern portions
of Baja California Sur through Sunday, with heavy rains reaching
Sinaloa later today, continuing through Monday. This rainfall will
produce flash and urban flooding, along with mudslides in areas of
higher terrain.

3. Norma is forecast to approach the west coast of Mexico as a
tropical storm on Sunday night and Monday, and a Tropical Storm
Warning is in effect for a portion of that area.


FORECAST POSITIONS AND MAX WINDS

INIT 21/1500Z 22.7N 110.3W 85 KT 100 MPH
12H 22/0000Z 23.4N 110.1W 75 KT 85 MPH...INLAND
24H 22/1200Z 24.1N 109.4W 60 KT 70 MPH...OVER WATER
36H 23/0000Z 24.5N 108.6W 50 KT 60 MPH
48H 23/1200Z 24.7N 107.7W 40 KT 45 MPH...INLAND
60H 24/0000Z 25.1N 106.8W 25 KT 30 MPH...POST-TROP/INLAND
72H 24/1200Z...DISSIPATED

$$
Forecaster Reinhart

[Yellow Evan]

Unraveling now but some heavy rains just offshore Cabo San Lucas on radar still.

[zeehag]

my part of mazatlan got a good hard rainfall stil l happening..much of mazatlan has sun and clear.. but my south mazatlan colonia still has lovely hard rains. sounds like they are dissipating now but was lovely.

[Sciencerocks]

[Sciencerocks]

 https://twitter.com/VortixWx/status/1715788685847695819

[cycloneye]

Hurricane Norma Tropical Cyclone Update
NWS National Hurricane Center Miami FL EP172023
215 PM MDT Sat Oct 21 2023

...NORMA MAKES LANDFALL IN BAJA CALIFORNIA SUR...

Satellite imagery indicates that Norma has made landfall in Baja
California Sur near El Pozo de Cota, which is west-northwest of Cabo
San Lucas. The maximum sustained winds are estimated to be 80 mph
(130 km/h), and the minimum central pressure is estimated at 978 mb
(28.88 inches).

SUMMARY OF 215 PM MDT...2015 UTC...INFORMATION
----------------------------------------------
LOCATION...23.0N 110.1W
ABOUT 15 MI...25 KM WNW OF CABO SAN LUCAS MEXICO
MAXIMUM SUSTAINED WINDS...80 MPH...130 KM/H
PRESENT MOVEMENT...NNE OR 15 DEGREES AT 7 MPH...11 KM/H
MINIMUM CENTRAL PRESSURE...978 MB...28.88 INCHES

$$
Forecaster Kelly/Reinhart

[Sciencerocks]

 https://twitter.com/VortixWx/status/1715840547993141542

[Sciencerocks]

[Sciencerocks]

[cycloneye]

Tropical Storm Norma Discussion Number 18
NWS National Hurricane Center Miami FL EP172023
900 PM MDT Sat Oct 21 2023

Norma continues to move across the southern portion of the Baja
California peninsula this evening. The satellite depiction of the
ill-defined low-level center has been difficult to track through the
terrain as the system has decoupled from the mid-level center.
Infrared satellite imagery indicates that there continues to be
bursts of convection on the northwest side. The land interaction,
increasingly southerly shear and dry air is causing Norma to weaken.
Subjective and objective Dvorak estimates for this advisory range
from 55 to 60 kt. Given the current satellite depiction and the
satellite intensity estimates, the initial intensity for this
advisory is set to 55 kt.

The tropical storm is moving north-northeastward or 30 degrees at
5 kt. The system will move across the southern portion of Baja
California Sur through tonight. Norma should emerge over the
southern Gulf of California early Sunday, then move northeastward to
east-northeastward and make landfall along the coast of Sinaloa in
western Mexico within the tropical storm warning area. The updated
NHC track forecast is similar to the previous, and lies between
the simple and corrected consensus aids.

Norma is expected to continue weakening due to the aforementioned
vertical wind shear, drier air, and land interaction. Once Norma
moves inland over mainland Mexico, it will quickly dissipate over
the high terrain. The intensity forecast is similar to the
previous advisory. The official forecast shows a 48 hour remnant
low point for continuity, however it is possible that the system
could be dissipated by that time.


Key Messages:

1. Heavy rains from Norma will continue to impact southern portions
of Baja California Sur through Sunday, and through Sinaloa into
Monday. This rainfall will produce flash and urban flooding, along
with mudslides in areas of higher terrain.

2. Tropical storm conditions will continue through tonight within
the Tropical Storm Warning area over the southern Baja California
peninsula.

3. Norma is forecast to bring tropical storm conditions to portions
of the west coast of mainland Mexico within the Tropical Storm
Warning area beginning early Sunday.


FORECAST POSITIONS AND MAX WINDS

INIT 22/0300Z 23.5N 109.7W 55 KT 65 MPH
12H 22/1200Z 24.1N 109.2W 50 KT 60 MPH...OVER WATER
24H 23/0000Z 24.5N 108.4W 45 KT 50 MPH
36H 23/1200Z 24.9N 107.7W 30 KT 35 MPH...INLAND
48H 24/0000Z 25.2N 106.8W 25 KT 30 MPH...POST-TROP/INLAND
60H 24/1200Z...DISSIPATED

$$
Forecaster Kelly

[Hurricane Mike]

Still some moisture but Norma is falling apart fast.

[Sciencerocks]

[Sciencerocks]

[cycloneye]

Hurricane Tammy Discussion Number 18
NWS National Hurricane Center Miami FL AL202023
500 PM AST Sun Oct 22 2023

The core of Tammy continues to pull away from the northern Leeward
Islands, but a trailing area of heavy rain continues to affect
portions of the Windward and Leeward Islands. The NOAA Hurricane
Hunters found maximum 750-mb flight-level winds of 83 kt and peak
SFMR winds of around 70 kt. In addition, the minimum pressure has
fallen to 988 mb. These data support nudging the initial intensity
up to 75 kt. Tammy continues to have a small central dense
overcast pattern in satellite images with very cold cloud tops
evident near the center. An ASCAT-B pass from a few hours ago was
helpful in adjusting the 34- and 50-kt wind radii, and it confirmed
that Tammy remains a relatively compact tropical cyclone.

The hurricane is moving northwestward at 8 kt on the southwestern
periphery of a subtropical ridge centered over the central Atlantic.
A turn to the north is forecast to occur late tonight, followed by a
northeastward motion beginning Monday night when a large-scale
trough over the northeast U.S. shifts eastward, eroding the ridge.
After that time, the models show the trough cutting off and merging
with Tammy, which will likely cause a sharp turn to the left. The
models have come in slightly better agreement in the overall
scenario, and only small changes were made to the previous NHC track
forecast.

Tammy will likely fluctuate in strength during the next few days
while it remains over warm SSTs and in a moderate wind shear
environment. After Tammy merges with the trough, dry air
entrainment and stronger shear should cause weakening and likely
lead to extratropical transition in 3 to 4 days. The NHC intensity
forecast is similar to the previous one and roughly in the middle
of the guidance envelope.


KEY MESSAGES:

1. The heaviest rains from Tammy will continue over the Leeward
Islands through tonight. This rainfall may produce isolated flash
and urban flooding, along with isolated mudslides in areas of higher
terrain.


FORECAST POSITIONS AND MAX WINDS

INIT 22/2100Z 19.9N 63.4W 75 KT 85 MPH
12H 23/0600Z 20.9N 63.8W 75 KT 85 MPH
24H 23/1800Z 22.0N 63.6W 80 KT 90 MPH
36H 24/0600Z 22.8N 62.9W 80 KT 90 MPH
48H 24/1800Z 23.6N 62.0W 80 KT 90 MPH
60H 25/0600Z 24.4N 61.0W 80 KT 90 MPH
72H 25/1800Z 25.8N 60.2W 75 KT 85 MPH
96H 26/1800Z 28.9N 60.4W 60 KT 70 MPH...POST-TROP/EXTRATROP
120H 27/1800Z 30.7N 64.3W 50 KT 60 MPH...POST-TROP/EXTRATROP

$$
Forecaster Cangialosi

[Sciencerocks]