EPAC: FLOSSIE - Post-Tropical - Discussion

[Yellow Evan]

Low easterly shear and divergent flow aloft suit the idea of significant intensification the next 3 days. However, its large, bandy nature will limit its rate of intensification and makes it vulnerable to dry air intrusions.

[cycloneye]

BULLETIN
Tropical Storm Flossie Intermediate Advisory Number 2A
NWS National Hurricane Center Miami FL EP062025
1200 PM CST Sun Jun 29 2025

...FLOSSIE MOVING WEST-NORTHWESTWARD...


SUMMARY OF 1200 PM CST...1800 UTC...INFORMATION
-----------------------------------------------
LOCATION...13.6N 100.1W
ABOUT 225 MI...370 KM S OF ACAPULCO MEXICO
ABOUT 465 MI...750 KM SE OF MANZANILLO MEXICO
MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H
PRESENT MOVEMENT...WNW OR 285 DEGREES AT 9 MPH...15 KM/H
MINIMUM CENTRAL PRESSURE...1005 MB...29.68 INCHES

[galaxy401]

Moisture from Flossie could bring some monsoon storms here in Arizona. Maybe it'll make a nice, cooler 4th of July.

[cycloneye]

BULLETIN
Tropical Storm Flossie Advisory Number 3
NWS National Hurricane Center Miami FL EP062025
300 PM CST Sun Jun 29 2025

...FLOSSIE CONTINUES WEST-NORTHWESTWARD...


SUMMARY OF 300 PM CST...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...13.5N 100.4W
ABOUT 235 MI...380 KM S OF ACAPULCO MEXICO
ABOUT 460 MI...740 KM SE OF MANZANILLO MEXICO
MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H
PRESENT MOVEMENT...WNW OR 295 DEGREES AT 8 MPH...13 KM/H
MINIMUM CENTRAL PRESSURE...1005 MB...29.68 INCHES



Tropical Storm Flossie Discussion Number 3
NWS National Hurricane Center Miami FL EP062025
300 PM CST Sun Jun 29 2025

Earlier SSMIS microwave data and satellite imagery depicted Flossie
becoming better organized with curved banding features. However,
recent imagery shows that banding has become a little more broken
since the previous advisory, as Flossie is still trying to organize
and consolidate. A 1600 UTC METOP-C scatterometer pass shows that
the low-level center has become better defined, however was slightly
south of the previously estimated position, and satellite-derived
winds were around 31 kt. Using the scatterometer data and the latest
subjective Dvorak intensity estimates T2.5, from both TAFB and SAB,
the intensity is held at 35 kt for this advisory.

Flossie is located within a favorable environment for strengthening
with warm sea surface temperatures, plentiful moisture and low to
moderate wind shear. As the system becomes better organized, steady
strengthening is forecast. Rapid intensification indices remain
elevated in latest SHIPS guidance, however RI is not explicitly
forecast at this time. The latest NHC intensity forecast is similar
to the previous, closest to the hurricane regional aids, but lies
slightly below the HCCA corrected consensus.

The current motion is estimated to be westward-northwestward around
295/7 kt. The storm is forecast moving west-northwestward with a
turn towards the northwest anticipated tomorrow around the western
periphery of a subtropical ridge. The latest track forecast is near
the previous, and lies between the simple and HCCA corrected
consensus aids.

Residents of Mexico should stay updated on the latest forecast. A
track even a little more to the right of the official forecast could
bring more significant impacts to the coast of southwestern Mexico.

KEY MESSAGES:

1. The outer bands of Tropical Storm Flossie may bring locally heavy
rainfall to the Mexican states of Oaxaca, Guerrero, Michoacán,
Colima, and Jalisco through early this week. Life-threatening
flooding and mudslides are possible, particularly in areas of steep
terrain.

2. A tropical storm watch is in effect for southwestern Mexico, and
tropical storm warnings could be required later tonight for a
portion of the coast of southern Mexico.


FORECAST POSITIONS AND MAX WINDS

INIT 29/2100Z 13.5N 100.4W 35 KT 40 MPH
12H 30/0600Z 14.3N 101.2W 45 KT 50 MPH
24H 30/1800Z 15.5N 102.7W 55 KT 65 MPH
36H 01/0600Z 16.8N 104.3W 70 KT 80 MPH
48H 01/1800Z 17.9N 106.0W 80 KT 90 MPH
60H 02/0600Z 19.0N 107.4W 85 KT 100 MPH
72H 02/1800Z 20.0N 108.8W 80 KT 90 MPH
96H 03/1800Z 22.0N 110.8W 55 KT 65 MPH
120H 04/1800Z 24.0N 113.1W 30 KT 35 MPH...POST-TROP/REMNT LOW

$$
Forecaster Kelly

[Hurricane2022]

Flossie has a perfect outflow right now. I'd be surprised if this peaks only at 100 mph, although her large size and less time over warm waters should limit the intensification overall

[Sciencerocks]

[cycloneye]

BULLETIN
Tropical Storm Flossie Intermediate Advisory Number 3A
NWS National Hurricane Center Miami FL EP062025
600 PM CST Sun Jun 29 2025

...FLOSSIE EXPECTED TO BRING AREAS OF HEAVY RAINS ALONG THE COAST
OF SOUTHWESTERN MEXICO...


SUMMARY OF 600 PM CST...0000 UTC...INFORMATION
----------------------------------------------
LOCATION...13.7N 100.7W
ABOUT 225 MI...360 KM SSW OF ACAPULCO MEXICO
ABOUT 435 MI...700 KM SE OF MANZANILLO MEXICO
MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H
PRESENT MOVEMENT...WNW OR 295 DEGREES AT 8 MPH...13 KM/H
MINIMUM CENTRAL PRESSURE...1005 MB...29.68 INCHES

[cycloneye]

Remains at T2.5.

A. 06E (FLOSSIE)

B. 30/0000Z

C. 13.8N

D. 100.4W

E. THREE/GOES-E

F. T2.5/2.5

G. IR/EIR/VIS

H. REMARKS...SYSTEM LACKS CORE CONVECTION AND CLOUD TOPS HAVE WARMED
OVER THE LAST 6 HOURS. 4/10 BANDING RESULTS IN A DT OF 2.5. MET AND PT
ARE ALSO 2.5. THE FT IS BASED ON THE MET BECAUSE BANDING IS NOT CLEAR CUT.

I. ADDL POSITIONS

NIL


...TURK

[cycloneye]

For now, the intensification has stopped.

EP, 06, 2025063000, , BEST, 0, 137N, 1007W, 35, 1005, TS

[DorkyMcDorkface]

After significant bout of convective warming (dry air intrusion?) a formidable burst has initiated. We'll see if this heralds more significant intensification.

[cycloneye]

BULLETIN
Tropical Storm Flossie Advisory Number 4
NWS National Hurricane Center Miami FL EP062025
900 PM CST Sun Jun 29 2025

...FLOSSIE EXPECTED TO BRING AREAS OF HEAVY RAINS ALONG THE COAST
OF SOUTHWESTERN MEXICO...


SUMMARY OF 900 PM CST...0300 UTC...INFORMATION
----------------------------------------------
LOCATION...14.0N 101.0W
ABOUT 215 MI...345 KM SSW OF ACAPULCO MEXICO
ABOUT 410 MI...655 KM SSE OF MANZANILLO MEXICO
MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H
PRESENT MOVEMENT...WNW OR 295 DEGREES AT 8 MPH...13 KM/H
MINIMUM CENTRAL PRESSURE...1005 MB...29.68 INCHES



Tropical Storm Flossie Discussion Number 4
NWS National Hurricane Center Miami FL EP062025
900 PM CST Sun Jun 29 2025

Flossie is holding steady as a broad tropical storm. New bursts of
deep convection are forming in the southern semicircle with cloud
top temperatures near -80 degrees C. Earlier microwave imagery
showed the circulation open to the east, indicating a possible dry
air intrusion. Subjective and objective satellite intensity
estimates range between 31 to 45 kt, with the majority near 35 kt.
Therefore, the intensity is held at 35 kt for this advisory.

The tropical storm is expected to strengthen during the next couple
of days. Warm waters, low vertical wind shear, and abundant
mid-level moisture should allow for Flossie to strengthen. Rapid
intensification indices are relatively high compared to climatology,
and the official NHC forecast shows periods of steady-to-rapid
intensification in the next two days. However, the forecast lies on
the high end of the intensity guidance envelope. Beyond the peak at
48 h, Flossie should gradually encounter a dry and stable airmass
and cross over cooling waters which will lead to steady weakening.

The current motion is westward-northwestward at 295/7 kt. Flossie is
forecast to move west-northwestward with a turn towards the
northwest anticipated soon around the western edge of a subtropical
ridge. The track guidance envelope shifted noticeably westward.
The latest track forecast shifted to the left of the previous
advisory, and lies on the right side of the envelope, closest to the
HCCA corrected consensus aid.

Residents of Mexico should stay updated on the latest forecast. A
shift in track to the right of the official forecast could bring
more significant impacts to the coast of southwestern Mexico.

KEY MESSAGES:

1. The outer bands of Tropical Storm Flossie may bring locally heavy
rainfall to the Mexican states of Oaxaca, Guerrero, Michoacán,
Colima, and Jalisco through early this week. Life-threatening
flooding and mudslides are possible, particularly in areas of steep
terrain.

2. A tropical storm watch is in effect for southwestern Mexico, and
tropical storm warnings could be required on Monday for a portion
of the coast of southern Mexico.


FORECAST POSITIONS AND MAX WINDS

INIT 30/0300Z 14.0N 101.0W 35 KT 40 MPH
12H 30/1200Z 14.8N 102.0W 45 KT 50 MPH
24H 01/0000Z 16.0N 103.6W 60 KT 70 MPH
36H 01/1200Z 17.2N 105.4W 75 KT 85 MPH
48H 02/0000Z 18.1N 106.9W 85 KT 100 MPH
60H 02/1200Z 19.1N 108.2W 80 KT 90 MPH
72H 03/0000Z 20.0N 109.3W 70 KT 80 MPH
96H 04/0000Z 22.0N 111.3W 50 KT 60 MPH
120H 05/0000Z 24.0N 113.7W 30 KT 35 MPH...POST-TROP/REMNT LOW

$$
Forecaster Bucci

[Yellow Evan]

270
WTPZ31 KNHC 300552
TCPEP1

BULLETIN
Tropical Storm Flossie Intermediate Advisory Number 4A
NWS National Hurricane Center Miami FL EP062025
1200 AM CST Mon Jun 30 2025

...FLOSSIE STARTING TO STRENGTHEN...
...EXPECTED TO BRING AREAS OF HEAVY RAIN ALONG THE COAST OF
SOUTHWESTERN MEXICO...


SUMMARY OF 1200 AM CST...0600 UTC...INFORMATION
-----------------------------------------------
LOCATION...14.4N 101.3W
ABOUT 195 MI...315 KM SSW OF ACAPULCO MEXICO
ABOUT 375 MI...605 KM SSE OF MANZANILLO MEXICO
MAXIMUM SUSTAINED WINDS...45 MPH...75 KM/H
PRESENT MOVEMENT...NW OR 305 DEGREES AT 9 MPH...14 KM/H
MINIMUM CENTRAL PRESSURE...1004 MB...29.65 INCHES


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

None.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Tropical Storm Watch is in effect for...
* Southwest coast of Mexico from Zihuatanejo to Cabo Corrientes

A Tropical Storm Watch means that tropical storm conditions are
possible within the watch area, generally within 48 hours.

Interests elsewhere in southwestern Mexico should monitor the
progress of Tropical Storm Flossie.

For storm information specific to your area, please monitor
products issued by your national meteorological service.


DISCUSSION AND OUTLOOK
----------------------
At 1200 AM CST (0600 UTC), the center of Tropical Storm Flossie was
located near latitude 14.4 North, longitude 101.3 West. Flossie is
moving toward the northwest near 9 mph (14 km/h). A west-northwest
to northwest motion should continue over the next few days.

Maximum sustained winds have increased to near 45 mph (75 km/h)
with higher gusts. Steady-to-rapid strengthening is forecast during
the next couple of days, and the system is expected to become a
hurricane tonight or Tuesday.

Tropical-storm-force winds extend outward up to 60 miles (95 km)
from the center.

The estimated minimum central pressure is 1004 mb (29.65 inches).


HAZARDS AFFECTING LAND
----------------------
Key messages for Tropical Storm Flossie can be found in the Tropical
Cyclone Discussion under AWIPS header MIATCDEP1 and WMO header
WTPZ41 KNHC.

RAINFALL: Tropical Storm Flossie is expected to produce rainfall
totals of 3 to 6 inches, with isolated maximum totals of 10 inches,
across portions of the Mexican states of Oaxaca, Guerrero,
Michoacán, Colima, and Jalisco through early this week. This
rainfall may lead to areas of life-threatening flooding and
mudslides, especially in areas of steep terrain.

For a complete depiction of forecast rainfall associated with
Tropical Storm Flossie, please see the National Weather Service
Storm Total Rainfall Graphic available at
hurricanes.gov/graphics_ep1.shtml?rainqpf

WIND: Tropical storm conditions are possible along the coast within
the watch area late today through Tuesday.

SURF: Swells generated by Flossie will affect portions of the coast
of southwestern Mexico during the next few days. These swells are
likely to cause life-threatening surf and rip current conditions.
Please consult products from your local weather office.


NEXT ADVISORY
-------------
Next complete advisory at 300 AM CST.

$$
Forecaster Hagen

[Yellow Evan]

Latest ASCAT while only supporting ~35 kts shows a much together wind field than earlier. Pressure likely dropping off that alone.

[cycloneye]

Tropical Storm Flossie Advisory Number 5
NWS National Hurricane Center Miami FL EP062025
300 AM CST Mon Jun 30 2025

...TROPICAL STORM WARNINGS ISSUED FOR PORTIONS OF THE
SOUTHWESTERN MEXICO COAST...
...FLOSSIE EXPECTED TO BRING AREAS OF HEAVY RAIN ALONG THE COAST OF
SOUTHWESTERN MEXICO...


SUMMARY OF 300 AM CST...0900 UTC...INFORMATION
----------------------------------------------
LOCATION...15.0N 101.8W
ABOUT 185 MI...300 KM S OF ZIHUATANEJO MEXICO
ABOUT 320 MI...520 KM SSE OF MANZANILLO MEXICO
MAXIMUM SUSTAINED WINDS...45 MPH...75 KM/H
PRESENT MOVEMENT...NW OR 315 DEGREES AT 10 MPH...17 KM/H
MINIMUM CENTRAL PRESSURE...1004 MB...29.65 INCHES




Tropical Storm Flossie Discussion Number 5
NWS National Hurricane Center Miami FL EP062025
300 AM CST Mon Jun 30 2025

A 30/0357 UTC ASCAT-B pass over Flossie showed a sizable area of
30-35 kt winds in the NE quadrant, with 25-30 kt winds wrapping into
portions of the SE and NW quadrants. The ASCAT data also indicates
that the RMW has contracted to about 40 n mi. SSMIS and GMI
microwave passes between 00-03Z were also helpful in diagnosing the
position and structure of Flossie. Since the time of the
above-mentioned microwave images, GOES satellite imagery indicates
that Flossie has started to become better organized, and it appears
that the low-level center is likely underneath the northern portion
of the central convective area, which has increased in size and
contains a large area of cloud tops colder than -80 degrees C. The
initial intensity is set to 40 kt due to the improved organization
since the time of the ASCAT pass. This estimate is also in line
with the latest objective intensity estimates from the UW-CIMSS ADT,
AiDT and DPRINT, which are running in the 40-45 kt range.

Atmospheric and oceanic conditions are expected to remain favorable
for intensification for at least another 48 h as Flossie moves
through an environment of warm water, weak vertical wind shear, and
a moist mid-level troposphere. Rapid intensification remains a
distinct possibility over the next day or two. The NHC forecast
continues to show steady to rapid intensification. The official
forecast is near the higher end of the intensity guidance envelope.
Beyond 48 h, Flossie should gradually encounter a dry and stable
airmass and cross over cooling waters which will lead to steady
weakening.

The initial motion estimate is toward the northwest, or 315/9 kt. A
motion between west-northwest and northwest should continue for the
next few days as Flossie moves through a break in the subtropical
ridge. The NHC track forecast is mostly unchanged from the previous
official forecast, and lies in between the simple and corrected
consensus aids.

The latest NHC forecast has necessitated the issuance of a Tropical
Storm Warning for portions of the coast of Mexico, as
tropical-storm-force wind speed probabilities are in the 40 to 50
percent range for portions of the area. Residents of Mexico should
stay updated on the latest forecast. A shift in track to the right
of the official forecast could bring more significant impacts to the
coast of southwestern Mexico.

KEY MESSAGES:

1. The outer bands of Tropical Storm Flossie may bring locally heavy
rainfall to the Mexican states of Oaxaca, Guerrero, Michoacán,
Colima, and Jalisco through mid-week. Life-threatening flooding and
mudslides are possible, particularly in areas of steep terrain.

2. A tropical storm warning has been issued for a portion of
southwestern Mexico, where tropical storm conditions are expected
late today through Tuesday.


FORECAST POSITIONS AND MAX WINDS

INIT 30/0900Z 15.0N 101.8W 40 KT 45 MPH
12H 30/1800Z 15.7N 102.9W 50 KT 60 MPH
24H 01/0600Z 16.8N 104.6W 65 KT 75 MPH
36H 01/1800Z 17.7N 106.3W 80 KT 90 MPH
48H 02/0600Z 18.5N 107.7W 85 KT 100 MPH
60H 02/1800Z 19.4N 108.8W 80 KT 90 MPH
72H 03/0600Z 20.4N 109.8W 65 KT 75 MPH
96H 04/0600Z 22.7N 111.9W 45 KT 50 MPH...POST-TROPICAL
120H 05/0600Z 24.9N 114.1W 25 KT 30 MPH...POST-TROP/REMNT LOW

$$
Forecaster Hagen

[cycloneye]

Look at the cold top convection how has expanded and that will cause intensification to be more fast.

[cycloneye]

BULLETIN
Tropical Storm Flossie Intermediate Advisory Number 5A
NWS National Hurricane Center Miami FL EP062025
600 AM CST Mon Jun 30 2025

...FLOSSIE A LITTLE STRONGER...


SUMMARY OF 600 AM CST...1200 UTC...INFORMATION
----------------------------------------------
LOCATION...15.2N 102.1W
ABOUT 175 MI...280 KM S OF ZIHUATANEJO MEXICO
ABOUT 300 MI...480 KM SSE OF MANZANILLO MEXICO
MAXIMUM SUSTAINED WINDS...50 MPH...85 KM/H
PRESENT MOVEMENT...NW OR 315 DEGREES AT 10 MPH...17 KM/H
MINIMUM CENTRAL PRESSURE...1000 MB...29.53 INCHES

[Hurricane2022]

Such a sad news we can't have any MW imagery now. I think Flossie may be starting to form a more defined core (or maybe even a weak Eyewall) at this moment.

[cycloneye]

Such a sad news we can't have any MW imagery now. I think Flossie may be starting to form a more defined core (or maybe even a weak Eyewall) at this moment.

From this morning? I thought it would be at midnight, but anyway is very bad to loose it.

[cycloneye]

A. 06E (FLOSSIE)

B. 30/1200Z

C. 15.1N

D. 102.0W

E. THREE/GOES-E

F. T3.0/3.0

G. IR/EIR/PRXY/ATMS

H. REMARKS...CONVECTION WRAPS JUST OVER .7 ON LOG10 SPIRAL YIELDING A
DT OF 3.0. MET OF 3.0 BASED ON SLOW DEVELOPMENT OVER THE LAST 24 HRS. PT
IS 3.0. THE FT IS BASED ON THE MET AS BANDING IS NOT CLEAR CUT.

I. ADDL POSITIONS

30/0821Z 15.0N 101.8W ATMS


...KIBLER

[cycloneye]

Such a sad news we can't have any MW imagery now. I think Flossie may be starting to form a more defined core (or maybe even a weak Eyewall) at this moment.

From this morning? I thought it would be at midnight, but anyway is very bad to loose it.

Heard news that it was extended to July 31rst.