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Tropical Major Hurricane Florence

532
WTNT31 KNHC 311731
TCPAT1

BULLETIN
Potential Tropical Cyclone Six Intermediate Advisory Number 5A
NWS National Hurricane Center Miami FL AL062018
200 PM AST Fri Aug 31 2018

...RAINBANDS AND GUSTY WINDS APPROACHING THE SOUTHERN CABO VERDE
ISLANDS...


SUMMARY OF 200 PM AST...1800 UTC...INFORMATION
----------------------------------------------
LOCATION...13.8N 23.3W
ABOUT 100 MI...165 KM SE OF THE SOUTHERNMOST CABO VERDE ISLANDS
MAXIMUM SUSTAINED WINDS...35 MPH...55 KM/H
PRESENT MOVEMENT...WNW OR 285 DEGREES AT 13 MPH...20 KM/H
MINIMUM CENTRAL PRESSURE...1006 MB...29.71 INCHES


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

None.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Tropical Storm Warning is in effect for...
* Cabo Verde Islands of Santiago, Fogo, and Brava

A Tropical Storm Warning means that tropical storm conditions are
expected somewhere within the warning area, in this case within the
next 12 hours.

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


DISCUSSION AND OUTLOOK
----------------------
At 200 PM AST (1800 UTC), the disturbance was centered near latitude
13.8 North, longitude 23.3 West. The system is moving toward the
west-northwest near 13 mph (20 km/h), and this motion with a slight
increase in forward speed is expected to continue for the next three
to four days. On the forecast track, the disturbance is expected to
continue moving near or over the southern Cabo Verde Islands as a
tropical storm later today and tonight.

Maximum sustained winds are near 35 mph (55 km/h) with higher
gusts. Strengthening is forecast during the next several days, and
the disturbance is expected to become a tropical storm later today
or Saturday.

Environmental conditions are favorable for the system to become a
tropical cyclone later today or tonight.
* Formation chance through 48 hours... high...90 percent
* Formation chance through 5 days...high...90 percent

The estimated minimum central pressure is 1006 mb (29.71 inches).


HAZARDS AFFECTING LAND
----------------------
RAINFALL: The system could produce total rain accumulations of 2
to 4 inches across the southern Cabo Verde Islands with isolated
maximum totals of 8 inches possible. These rains could produce
life-threatening flash floods.

WINDS: Tropical storm conditions are expected in the southern Cabo
Verde Islands later today and tonight.


NEXT ADVISORY
-------------
Next complete advisory at 500 PM AST.

$$
Forecaster Avila
 
Not quite as vivid (or explanatory) as can be seen on the link for the water vapor loop up at Post #22, but this does give an nice view of a system getting itself ready to rock 'n roll ...

hiatlsat_None_anim.gif
 
Last edited:
611
WTNT31 KNHC 312032
TCPAT1

BULLETIN
Tropical Depression Six Advisory Number 6
NWS National Hurricane Center Miami FL AL062018
500 PM AST Fri Aug 31 2018

...TROPICAL DEPRESSION FORMS JUST SOUTH OF THE CABO VERDE
ISLANDS...
...RAINBANDS AND GUSTY WINDS AFFECTING THOSE ISLANDS...


SUMMARY OF 500 PM AST...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...13.8N 24.7W
ABOUT 70 MI...115 KM SSW OF THE SOUTHERNMOST CABO VERDE ISLANDS
MAXIMUM SUSTAINED WINDS...35 MPH...55 KM/H
PRESENT MOVEMENT...W OR 270 DEGREES AT 15 MPH...24 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 Warning is in effect for...
* Cabo Verde Islands of Santiago, Fogo, and Brava

A Tropical Storm Warning means that tropical storm conditions are
expected somewhere within the warning area, in this case within the
next 6 to 12 hours.

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


DISCUSSION AND OUTLOOK
----------------------
At 500 PM AST (2100 UTC), the center of newly formed Tropical
Depression Six was located near latitude 13.8 North, longitude 24.7
West. The depression is moving toward the west near 15 mph (24
km/h), and this track with a gradual turn to the west-northwest is
expected for the next two or three days. On the forecast track, the
depression will be passing just south of the Cabo Verde Islands
tonight and Saturday. The depression should then be moving over the
open eastern Atlantic on Sunday and Monday.

Maximum sustained winds are near 35 mph (55 km/h) with higher gusts.
Strengthening is forecast, and the depression is expected to become
a tropical storm tonight or Saturday.

The estimated minimum central pressure based on observations from
the Cabo Verde Islands is 1004 mb (29.65 inches).


HAZARDS AFFECTING LAND
----------------------
RAINFALL: The system could produce total rain accumulations of 2
to 4 inches across the southern Cabo Verde Islands with isolated
maximum totals of 8 inches possible. These rains could produce
life-threatening flash floods.

WINDS: Tropical storm conditions are expected to continue in the
southern Cabo Verde Islands tonight. Winds should subside on
Saturday.


NEXT ADVISORY
-------------
Next intermediate advisory at 800 PM AST.
Next complete advisory at 1100 PM AST.

$$
Forecaster Avila
848
WTNT41 KNHC 312033
TCDAT1

Tropical Depression Six Discussion Number 6
NWS National Hurricane Center Miami FL AL062018
500 PM AST Fri Aug 31 2018

High resolution satellite images reveal that the disturbance has
developed a well-defined circulation with a cyclonically curved
convective band near the center, and plenty of showers in the
southern semicircle. The surface pressure in the Cabo Verde Island
of Santiago dropped to 1005 mb at 1800 UTC as the cyclone passed to
its south. In addition, Dvorak numbers are gradually increasing, and
now support classifying the system as a tropical depression.

The depression is becoming better organized, and it will most likely
reach tropical storm status in the next several hours. The
environmental conditions are favorable for some strengthening during
the next 2 to 3 days while the shear is low. Later in the forecast
period, the shear is expected to increase, and the SSTs will become
marginal halting the strengthing process. The models, primarily the
HWRF, are a little less aggressive with the intensity, so the NHC
forecast is adjusted slightly downward.

Now that the center has formed, we have a better estimate of the
initial motion, which is toward the west or 270 degrees at 13 kt.
The depression is gradually becoming steered by the flow around the
subtropical ridge, and consequently it has increased its forward
speed. This prevailing flow pattern should keep the cyclone on a
general west to west-northwest track for the next 2 to 3 days. After
that time, a weakness in the ridge will induce a more northwestward
to north-northwestward track over the open Atlantic Ocean. The
track guidance is very consistent with this solution mainly for the
next 3 days. Thereafter, the confidence in the track forecast
decreases as the guidance envelope widens and becomes bounded by the
westernmost ECMWF and the easternmost HWFI. The NHC forecast
continues to be in the middle of the envelope and is very close
to the corrected consensus HCCA, which has had great skill so far
this year.


FORECAST POSITIONS AND MAX WINDS

INIT 31/2100Z 13.8N 24.7W 30 KT 35 MPH
12H 01/0600Z 14.3N 26.7W 35 KT 40 MPH
24H 01/1800Z 14.9N 29.2W 40 KT 45 MPH
36H 02/0600Z 15.8N 31.8W 45 KT 50 MPH
48H 02/1800Z 16.5N 34.5W 50 KT 60 MPH
72H 03/1800Z 18.0N 39.5W 55 KT 65 MPH
96H 04/1800Z 20.0N 44.0W 60 KT 70 MPH
120H 05/1800Z 23.0N 48.0W 55 KT 65 MPH

$$
Forecaster Avila
 
GFS/HWRF/Fv3 developed PTC 6 way too quickly and likely still are, a solution somewhere in the middle of the GFS/Euro intensity wise w/ slightly more weight on the euro seems somewhat reasonable. I personally agree that the potential for anything more than a low grade hurricane thru about day 5-6 is fairly low here, thereafter conditions look much more conducive in the subtropics, and yeah there's still a lot of spread in the guidance
 
990
WTNT31 KNHC 312342
TCPAT1

BULLETIN
Tropical Depression Six Intermediate Advisory Number 6A
NWS National Hurricane Center Miami FL AL062018
800 PM AST Fri Aug 31 2018

...TROPICAL DEPRESSION PASSING SOUTH OF THE CABO VERDE ISLANDS...
...RAINBANDS AND GUSTY WINDS AFFECTING THOSE ISLANDS...


SUMMARY OF 800 PM AST...0000 UTC...INFORMATION
----------------------------------------------
LOCATION...14.0N 25.0W
ABOUT 65 MI...105 KM SSW OF BRAVA IN THE CABO VERDE ISLANDS
MAXIMUM SUSTAINED WINDS...35 MPH...55 KM/H
PRESENT MOVEMENT...W OR 270 DEGREES AT 15 MPH...24 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 Warning is in effect for...
* Cabo Verde Islands of Santiago, Fogo, and Brava

A Tropical Storm Warning means that tropical storm conditions are
expected somewhere within the warning area, in this case within the
next 6 to 12 hours.

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


DISCUSSION AND OUTLOOK
----------------------
At 800 PM AST (0000 UTC), the center of Tropical Depression Six was
located near latitude 14.0 North, longitude 25.0 West. The
depression is moving toward the west near 15 mph (24 km/h), and this
track with a gradual turn to the west-northwest is expected for the
next two or three days. On the forecast track, the depression will
be passing just south of the Cabo Verde Islands tonight and Saturday
morning. The depression should then be moving over the open eastern
Atlantic on Sunday and Monday.

Maximum sustained winds are near 35 mph (55 km/h) with higher
gusts. Strengthening is forecast, and the depression is expected to
become a tropical storm tonight or Saturday.

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


HAZARDS AFFECTING LAND
----------------------
RAINFALL: The system could produce total rain accumulations of 2
to 4 inches across the southern Cabo Verde Islands with isolated
maximum totals of 8 inches possible. These rains could produce
life-threatening flash floods.

WINDS: Tropical storm conditions are expected to continue in the
southern Cabo Verde Islands tonight. Winds should subside on
Saturday.


NEXT ADVISORY
-------------
Next complete advisory at 1100 PM AST.

$$
Forecaster Beven
 
the 0z Euro is uh really interesting, I had to rewind the run to make sure that was Florence approaching the SE US at Day 10 with a huge ridge to the north and east
 
Florence is official and the NHC already noting the huge model changes

The European model, in particular, swung
significantly to the left, showing a weaker Florence not feeling the
break in the ridge quite as much. I'd like to see this trend
continue before making a significant change to the forecast, so for
now the updated NHC track prediction is only nudged westward. That
said, the models appear to be trending away from a definitive
recurvature scenario.
 
Last night's 0Z Euro kept Florence weak through about day 6-7 preventing easy escape OTS. EURO and UKMET appear to be the furthest South on last night's runs.
euro 120.png euro 240.png
 
Last night's 0Z Euro kept Florence weak through about day 6-7 preventing easy escape OTS. EURO and UKMET appear to be the furthest South on last night's runs.
View attachment 5793 View attachment 5794
Long way to go of course but at the end of that run Florence was heading west but that high appears to be breaking down so if that run continued probably a close pass to the EC.... but yeah staying weaker longer "could" spell trouble later.
 
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