EPAC: FERNANDA - Remnants - Discussion

[Yellow Evan]

TXPZ23 KNES 121216
TCSENP

A. TROPICAL DISTURBANCE (98E)

B. 12/1200Z

C. 13.7N

D. 112.0W

E. FIVE/GOES-W

F. T1.0/1.0

G. IR/EIR/SWIR

H. REMARKS...>2/10 BANDING YIELDS A DT OF 1.0. THE MET AND PT BOTH
AGREE. THE FT IS BASED ON THE DT.

I. ADDL POSITIONS

NIL


...BROWN

[Yellow Evan]

Not sure what the NHC is referring to by saying there isn't a well-defined circulation based on satellite derived wind data fwiw given ASCAT missed.

[Sciencerocks]

[Sciencerocks]

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
500 AM PDT Sat Aug 12 2023

For the eastern North Pacific...east of 140 degrees west longitude:

Central East Pacific (EP98):
Showers and thunderstorms continue to show signs of organization in
association with an area of low pressure located several hundred
miles south of the southern tip of the Baja California peninsula.
However, satellite-derived wind data from overnight indicated that
the system did not yet have a well-defined center of circulation.
Environmental conditions are conducive for additional development of
this system, and a tropical depression is expected to form during
the next day or two while it moves westward or northwestward at
about 10 mph across the central portion of the basin.
* Formation chance through 48 hours...high...80 percent.
* Formation chance through 7 days...high...90 percent.

[Extratropical94]

TAFB with a T1.5

EP, 98, 202308121200, 10, DVTS, CI, , 1400N, 11170W, , 2, 25, 2, , 2, DVRK, , , , , , , , , , , , , , E, TAFB, EC, I, 3, 1515 /////, , , GOES18, CSC, T, Banding is getting more organized

https://ftp.nhc.noaa.gov/atcf/fix/fep982023.dat

[cycloneye]

TAFB with a T1.5

EP, 98, 202308121200, 10, DVTS, CI, , 1400N, 11170W, , 2, 25, 2, , 2, DVRK, , , , , , , , , , , , , , E, TAFB, EC, I, 3, 1515 /////, , , GOES18, CSC, T, Banding is getting more organized

https://ftp.nhc.noaa.gov/atcf/fix/fep982023.dat

Oh boy, only minutes after advisory time.

[Yellow Evan]

Can see northerlies here which ASCAT at 4z lacked. Clear TC now.

[Extratropical94]

Central East Pacific (EP98):
Showers and thunderstorms continue to become better organized in
association with a low pressure system located several hundred
miles south-southwest of the southern tip of the Baja California
peninsula, and it appears that a tropical depression or tropical
storm could be forming. If these trends continue, advisories would
likely be initiated on this system later today. The low is expected
to move westward to west-northwestward at about 10 mph across the
central portion of the basin during the next few days.
* Formation chance through 48 hours...high...90 percent.
* Formation chance through 7 days...high...90 percent.

[Kingarabian]

Ah the good ole let's wait until its a TS so we can raise the odds to 90/90

[Extratropical94]

No renumber yet

Meanwhile, a 2.0 from TAFB

EP, 98, 202308121800, 10, DVTS, CI, , 1430N, 11280W, , 3, 30, 2, 1009, 2, DVRK, , , , , , , , , , , , , , E, TAFB, ERA, VI, 5, 2020 /////, , , GOES18, CSC, T,

Edit: Spoke too soon: We have Seven

EP, 07, 2023081218, , BEST, 0, 146N, 1126W, 30, 1007, DB, 34, NEQ, 0, 0, 0, 0, 1011, 140, 50, 0, 0, E, 0, , 0, 0, SEVEN, M, 0, , 0, 0, 0, 0, TRANSITIONED, epA82023 to ep072023,

[cycloneye]

[ElectricStorm]

It's listed as PTC7 on TT. Not sure why a PTC designation would be needed here when there's no land in it's path and it seems like a TD already...

I'd imagine the NHC will call it a depression at the upcoming advisory

[Extratropical94]

It's listed as PTC7 on TT. Not sure why a PTC designation would be needed here when there's no land in it's path and it seems like a TD already...

Could be that TT's script automatically tags it as a PTC because it has a number, but is still listed as a disturbance (DB) and not a TD in the best track file. Once the BT updates to TD, it should appear as a TD on the website.

[Sciencerocks]

[Sciencerocks]

Tropical Depression Seven-E Discussion Number 1
NWS National Hurricane Center Miami FL EP072023
300 PM MDT Sat Aug 12 2023

Satellite images indicate that the area of low pressure located
several hundred miles south-southwest of the southern tip of the
Baja California peninsula has attained sufficient organization to be
classified as a tropical depression. The last couple of microwave
satellite overpasses show a similar scenario, with cold
convective curved bands becoming better organized around a low-level
center, which appears to be located near the northern edge of the
convective cloud mass based on recent visible satellite images. The
latest TAFB subjective Dvorak estimate is T-2.0. Based on these
data, Invest 98E is upgraded to Tropical Depression Seven-E with an
initial intensity of 30 kt.

Weak mid-level ridging well to the north of the depression will
steer the cyclone toward the west-northwest at about 10 kt over the
next few days. Beyond 72 h, the ridge should strengthen enough to
cause a turn to the west with a slight increase in forward speed.
The NHC forecast track is in best agreement with the HCCA and TVCE
consensus models.

Environmental conditions are quite favorable for strengthening over
the next 48-60 h, with warm ocean temperatures, low vertical
wind shear and a relatively moist low to mid-level troposphere. The
NHC forecast peaks the system at 75 kt in 48-60 h, which is near
the middle of the intensity guidance. The ECMWF version of the
SHIPS RI index shows a 52 percent chance of a 65 kt increase in
winds over the next 72 h, so there is a chance the cyclone could
strengthen more than forecast. After that time, the cyclone is
forecast to move into a much drier environment along with slowly
decreasing sea-surface temperatures. There is high confidence on
significant weakening beyond 72 h due to the very dry airmass that
the cyclone will be moving into.

FORECAST POSITIONS AND MAX WINDS

INIT 12/2100Z 14.9N 113.2W 30 KT 35 MPH
12H 13/0600Z 15.2N 114.2W 40 KT 45 MPH
24H 13/1800Z 15.5N 115.9W 50 KT 60 MPH
36H 14/0600Z 15.7N 117.6W 60 KT 70 MPH
48H 14/1800Z 16.1N 119.2W 75 KT 85 MPH
60H 15/0600Z 16.6N 120.8W 75 KT 85 MPH
72H 15/1800Z 17.1N 122.8W 70 KT 80 MPH
96H 16/1800Z 17.6N 127.7W 50 KT 60 MPH
120H 17/1800Z 17.8N 133.1W 35 KT 40 MPH

$$
Forecaster Hagen/Berg

[Sciencerocks]

banding so suggestive of a 35 knot system

[cycloneye]

Hello Fernanda.

EP, 07, 2023081300, , BEST, 0, 149N, 1136W, 35, 1005, TS, 34, NEQ, 50, 50, 0, 0, 1011, 140, 40, 0, 0, E, 0, , 0, 0, FERNANDA,

[Sciencerocks]

[cycloneye]

Tropical Storm Fernanda Discussion Number 2
NWS National Hurricane Center Miami FL EP072023
900 PM MDT Sat Aug 12 2023

Satellite imagery indicates that the storm is producing more
organized convection and curved bands now wrap about half way around
the center. The system appears to be on a strengthening trend with
visible satellite images showing a compact structure. The initial
intensity has increased up to 40 kt, which is slightly above the
latest Dvorak estimates, making it a tropical storm.

Fernanda is moving to the west-northwest at about 9 kt. This general
motion is expected to continue through the next few days at a slower
pace as it moves towards a weakness in the subtropical ridge. Around
mid-week, the system is anticipated to move more westward at a
faster forward speed due to a strengthening ridge to its north.
There is some spread in the models, especially at days 4 and 5, but
they generally agree on the future track. No significant changes
were made from the previous forecast.

Steady to rapid intensification is possible during the next 36 hours
as Fernanda remains over warm 29C waters in low wind shear
conditions. Fernanda could reach a peak intensity around 80 kt
Monday and Tuesday, and some models suggest a slightly higher
strength. By late Tuesday, the system is expected to move over
cooler waters and into a drier environment which should lead to a
weakening trend. The new NHC forecast shows the intensity increase
at a faster rate during the next 24 to 36 hours.


FORECAST POSITIONS AND MAX WINDS

INIT 13/0300Z 15.0N 114.0W 40 KT 45 MPH
12H 13/1200Z 15.3N 115.2W 50 KT 60 MPH
24H 14/0000Z 15.7N 116.9W 65 KT 75 MPH
36H 14/1200Z 16.0N 118.3W 80 KT 90 MPH
48H 15/0000Z 16.4N 120.0W 80 KT 90 MPH
60H 15/1200Z 16.9N 121.8W 80 KT 90 MPH
72H 16/0000Z 17.3N 123.9W 70 KT 80 MPH
96H 17/0000Z 17.7N 128.9W 50 KT 60 MPH
120H 18/0000Z 17.8N 134.5W 35 KT 40 MPH

$$
Forecaster Cangialosi

[Yellow Evan]

Quickly developing a core.