EPAC: NARDA - Remnants - Discussion

[cycloneye]

BULLETIN
Tropical Storm Narda Advisory Number 26
NWS National Hurricane Center Miami FL EP142025
800 PM PDT Sat Sep 27 2025

...NARDA STEADILY WEAKENING AS IT BEGINS TO TURN NORTHWARD...


SUMMARY OF 800 PM PDT...0300 UTC...INFORMATION
----------------------------------------------
LOCATION...18.7N 125.9W
ABOUT 1070 MI...1725 KM WSW OF THE SOUTHERN TIP OF BAJA CALIFORNIA
MAXIMUM SUSTAINED WINDS...70 MPH...110 KM/H
PRESENT MOVEMENT...NNW OR 335 DEGREES AT 5 MPH...7 KM/H
MINIMUM CENTRAL PRESSURE...991 MB...29.27 INCHES



Tropical Storm Narda Discussion Number 26
NWS National Hurricane Center Miami FL EP142025
800 PM PDT Sat Sep 27 2025

Narda has weakened this evening as it tracks over progressively
cooler waters and into a drier environment. Subjective Dvorak
intensity estimates from SAB and TAFB were T4.0/65 kt, with
objective estimates from UW-CIMSS in the 54–64 kt range. Given the
weakening trend shown on satellite since these estimates, the
initial intensity is set at 60 kt, and Narda is now a tropical
storm.

The initial motion is north-northwestward at about 335/4 kt. A
gradual turn toward the north is forecast tonight, with this motion
expected to persist through the remainder of the weekend as it
responds to a weakness in the subtropical ridge. Early next week,
Narda should become shallow and increasingly steered by the
low-level flow, leading to a turn back toward the northwest before
dissipation. The forecast track is very close to the previous
advisory and remains near the middle of the guidance envelope.

Continued weakening is expected as Narda moves farther north into
progressively cooler waters and a drier, more stable environment.
The system is forecast to become post-tropical within 36 hours and
dissipate around day 5. The intensity forecast is very similar to
the previous one and is close to the consensus aids.


FORECAST POSITIONS AND MAX WINDS

INIT 28/0300Z 18.7N 125.9W 60 KT 70 MPH
12H 28/1200Z 19.4N 126.1W 55 KT 65 MPH
24H 29/0000Z 20.4N 126.1W 45 KT 50 MPH
36H 29/1200Z 21.1N 125.9W 40 KT 45 MPH...POST-TROPICAL
48H 30/0000Z 21.6N 125.6W 35 KT 40 MPH...POST-TROPICAL
60H 30/1200Z 22.1N 125.5W 30 KT 35 MPH...POST-TROP/REMNT LOW
72H 01/0000Z 22.8N 125.9W 25 KT 30 MPH...POST-TROP/REMNT LOW
96H 02/0000Z 24.0N 126.9W 20 KT 25 MPH...POST-TROP/REMNT LOW
120H 03/0000Z...DISSIPATED

$$
Forecaster Gibbs (CPHC)

[cycloneye]

BULLETIN
Tropical Storm Narda Advisory Number 27
NWS National Hurricane Center Miami FL EP142025
200 AM PDT Sun Sep 28 2025

...NARDA WEAKENING OVER COOLER WATERS AS IT CONTINUES NORTHWARD...


SUMMARY OF 200 AM PDT...0900 UTC...INFORMATION
----------------------------------------------
LOCATION...19.1N 125.6W
ABOUT 1045 MI...1680 KM WSW OF THE SOUTHERN TIP OF BAJA CALIFORNIA
MAXIMUM SUSTAINED WINDS...60 MPH...95 KM/H
PRESENT MOVEMENT...N OR 360 DEGREES AT 5 MPH...7 KM/H
MINIMUM CENTRAL PRESSURE...997 MB...29.44 INCHES



Tropical Storm Narda Discussion Number 27
NWS National Hurricane Center Miami FL EP142025
200 AM PDT Sun Sep 28 2025

Satellite imagery indicates that Narda’s convection has continued to
diminish in coverage. The remaining deep convection is confined
mainly to the southern semicircle, with cloud tops warming to near
–65 C. A 0439 UTC METOP-B ASCAT pass showed peak surface winds of
about 45 kt in the southeastern quadrant. Objective estimates from
UW-CIMSS range from 47 to 57 kt. Based on a blend of these data,
the initial intensity is set at 50 kt.

The cyclone is moving northward at about 360/4 kt, and this general
motion is expected to continue through the remainder of the weekend.
As Narda steadily loses convection and becomes increasingly shallow,
it should turn back toward the northwest within the low-level flow
before dissipating around midweek. The forecast track is very
similar to the previous advisory and remains close to the
multi-model consensus aids.

Narda has rapidly weakened over the past 24 hours due to cooler sea
surface temperatures and the influence of a drier, more stable air
mass. Additional steady weakening is forecast, and the system is
expected to become post-tropical by Monday and dissipate by the
middle of next week. The official intensity forecast is similar to
the previous advisory and remains close to the consensus guidance.


FORECAST POSITIONS AND MAX WINDS

INIT 28/0900Z 19.1N 125.6W 50 KT 60 MPH
12H 28/1800Z 19.9N 125.5W 45 KT 50 MPH
24H 29/0600Z 20.9N 125.3W 35 KT 40 MPH...POST-TROPICAL
36H 29/1800Z 21.4N 125.0W 30 KT 35 MPH...POST-TROP/REMNT LOW
48H 30/0600Z 21.7N 124.8W 25 KT 30 MPH...POST-TROP/REMNT LOW
60H 30/1800Z 22.1N 125.0W 20 KT 25 MPH...POST-TROP/REMNT LOW
72H 01/0600Z 22.6N 125.7W 20 KT 25 MPH...POST-TROP/REMNT LOW
96H 02/0600Z...DISSIPATED

$$
Forecaster Gibbs (CPHC)

[cycloneye]

BULLETIN
Tropical Storm Narda Advisory Number 28
NWS National Hurricane Center Miami FL EP142025
800 AM PDT Sun Sep 28 2025

...NARDA CONTINUES WEAKENING OVER OPEN WATERS...
...LIKELY TO BECOME POST-TROPICAL LATER TODAY OR EARLY MONDAY...


SUMMARY OF 800 AM PDT...1500 UTC...INFORMATION
----------------------------------------------
LOCATION...19.7N 125.5W
ABOUT 1025 MI...1655 KM W OF THE SOUTHERN TIP OF BAJA CALIFORNIA
MAXIMUM SUSTAINED WINDS...50 MPH...85 KM/H
PRESENT MOVEMENT...N OR 5 DEGREES AT 6 MPH...9 KM/H
MINIMUM CENTRAL PRESSURE...1000 MB...29.53 INCHES


Tropical Storm Narda Discussion Number 28
NWS National Hurricane Center Miami FL EP142025
800 AM PDT Sun Sep 28 2025

Convection associated with Narda continues to diminish in coverage
and organization this morning. Subjective and objective satellite
intensity estimates are decreasing, and the initial intensity is
lowered to 45 kt for this advisory. This is in good agreement
with the latest UW-CIMSS objective estimates and consistent with
the overnight scatterometer data.

Continued weakening is expected as Narda remains over cooler waters
within a drier, stable environment. This forecast indicates that
Narda could become post-tropical later today or early Monday. The
storm is moving northward at about 5 kt. A slow northward or
north-northeastward motion is expected for the next day or two,
followed by a northwestward turn as the remnant low becomes steered
by the low-level flow. The remnant low is forecast to degenerate to
a surface trough later this week. No notable changes were made to
the NHC track or intensity forecasts.


FORECAST POSITIONS AND MAX WINDS

INIT 28/1500Z 19.7N 125.5W 45 KT 50 MPH
12H 29/0000Z 20.4N 125.2W 35 KT 40 MPH...POST-TROPICAL
24H 29/1200Z 21.2N 124.9W 30 KT 35 MPH...POST-TROP/REMNT LOW
36H 30/0000Z 21.6N 124.6W 25 KT 30 MPH...POST-TROP/REMNT LOW
48H 30/1200Z 22.0N 124.7W 25 KT 30 MPH...POST-TROP/REMNT LOW
60H 01/0000Z 22.4N 125.1W 20 KT 25 MPH...POST-TROP/REMNT LOW
72H 01/1200Z 23.1N 126.0W 20 KT 25 MPH...POST-TROP/REMNT LOW
96H 02/1200Z...DISSIPATED

$$
Forecaster Reinhart

[cycloneye]

BULLETIN
Tropical Storm Narda Advisory Number 29
NWS National Hurricane Center Miami FL EP142025
200 PM PDT Sun Sep 28 2025

...NARDA QUICKLY WEAKENING...
...EXPECTED TO BECOME POST-TROPICAL THIS EVENING...


SUMMARY OF 200 PM PDT...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...20.4N 125.4W
ABOUT 1010 MI...1625 KM W OF THE SOUTHERN TIP OF BAJA CALIFORNIA
MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H
PRESENT MOVEMENT...N OR 5 DEGREES AT 8 MPH...13 KM/H
MINIMUM CENTRAL PRESSURE...1008 MB...29.77 INCHES




Tropical Storm Narda Discussion Number 29
NWS National Hurricane Center Miami FL EP142025
200 PM PDT Sun Sep 28 2025

Narda has become practically devoid of deep convection, and what
remains is not well-organized. ASCAT-B data valid at 1708 UTC
revealed a swath of 30-35 kt winds to the southeast of Narda's
center, and that is the basis for the 35-kt initial intensity.

Simulated satellite imagery from the GFS, ECMWF and regional
hurricane models indicate that Narda is unlikely to redevelop deep
convection. Given its very dry environment and SSTs below 24 deg C,
that forecast appears likely to verify. Narda should therefore
become a post-tropical remnant low this evening. The cyclone is
still forecast to drift slowly northward to north-northeastward for
the next day or so, and then turn northwestward after that until it
dissipates near the middle of the week. No substantial changes were
made to the official forecast, except to account for the lower
intensity based on the ASCAT data.


FORECAST POSITIONS AND MAX WINDS

INIT 28/2100Z 20.4N 125.4W 35 KT 40 MPH
12H 29/0600Z 21.1N 125.1W 30 KT 35 MPH...POST-TROPICAL
24H 29/1800Z 21.6N 124.7W 25 KT 30 MPH...POST-TROP/REMNT LOW
36H 30/0600Z 21.8N 124.5W 25 KT 30 MPH...POST-TROP/REMNT LOW
48H 30/1800Z 22.1N 124.7W 20 KT 25 MPH...POST-TROP/REMNT LOW
60H 01/0600Z 22.6N 125.4W 20 KT 25 MPH...POST-TROP/REMNT LOW
72H 01/1800Z 23.2N 126.4W 20 KT 25 MPH...POST-TROP/REMNT LOW
96H 02/1800Z...DISSIPATED

$$
Forecaster D. Zelinsky

[cycloneye]

Bye.

BULLETIN
Post-Tropical Cyclone Narda Advisory Number 30
NWS National Hurricane Center Miami FL EP142025
800 PM PDT Sun Sep 28 2025

...NARDA HAS BECOME A REMNANT LOW...
...THIS IS THE LAST ADVISORY...


SUMMARY OF 800 PM PDT...0300 UTC...INFORMATION
----------------------------------------------
LOCATION...20.9N 125.1W
ABOUT 985 MI...1580 KM W OF THE SOUTHERN TIP OF BAJA CALIFORNIA
MAXIMUM SUSTAINED WINDS...35 MPH...55 KM/H
PRESENT MOVEMENT...NNE OR 30 DEGREES AT 6 MPH...9 KM/H
MINIMUM CENTRAL PRESSURE...1009 MB...29.80 INCHES



Post-Tropical Cyclone Narda Discussion Number 30
NWS National Hurricane Center Miami FL EP142025
800 PM PDT Sun Sep 28 2025

Cooler waters and dry mid-level air have taken a significant toll on
Narda. The cyclone has been devoid of organized deep convection for
several hours, leaving mainly a swirl of low- to mid-level clouds.
The initial intensity is reduced to a possibly generous 30 kt. Given
the increasingly hostile environment, along with strengthening
southwesterly shear expected during the next day or so, regeneration
of organized convection is not anticipated. As a result, this will
be the final advisory on Narda, which has become a post-tropical
remnant low.

The remnant low is forecast to drift north-northeastward into
Monday, before turning back toward the northwest by Tuesday as it
becomes steered by the low-level flow. Global model guidance
indicates that the system should gradually spin down and open into a
trough of low pressure within about 4 days.

For additional information on the remnant low, please see High Seas
Forecasts issued by the National Weather Service, under AWIPS header
NFDHSFEPI, WMO header FZPN02 KWBC, and on the web at
ocean.weather.gov/shtml/NFDHSFEPI.php


FORECAST POSITIONS AND MAX WINDS

INIT 29/0300Z 20.9N 125.1W 30 KT 35 MPH...POST-TROP/REMNT LOW
12H 29/1200Z 21.4N 124.8W 25 KT 30 MPH...POST-TROP/REMNT LOW
24H 30/0000Z 21.6N 124.5W 25 KT 30 MPH...POST-TROP/REMNT LOW
36H 30/1200Z 21.9N 124.5W 20 KT 25 MPH...POST-TROP/REMNT LOW
48H 01/0000Z 22.2N 125.0W 20 KT 25 MPH...POST-TROP/REMNT LOW
60H 01/1200Z 22.5N 126.1W 20 KT 25 MPH...POST-TROP/REMNT LOW
72H 02/0000Z 23.0N 127.2W 20 KT 25 MPH...POST-TROP/REMNT LOW
96H 03/0000Z...DISSIPATED

$$
Forecaster Gibbs (CPHC)