t02436

即將開始加速移動，強度也將重回C1。
飛機實測將在稍後啟動，未來將挑戰原先115節巔峰強度，目前預測五天後以C4強度登陸。

701
WTNT41 KNHC 090844
TCDAT1

Tropical Storm Florence Discussion Number  40
NWS National Hurricane Center Miami FL       AL062018
500 AM AST Sun Sep 09 2018

Florence's cloud pattern has continued to gradually become better
organized overnight, with an increase in convection near the center
and a developing central dense overcast feature.  However, the
cloud tops are not particularly cold and the outer banding features
remain fragmented likely due to some nearby dry mid-level air.
Dvorak intensity estimates from TAFB and SAB range from 55 to 65
kt, so the initial intensity remains 60 kt, just shy of hurricane
strength.  The NOAA Hurricane Hunters are scheduled to investigate
the storm later today, and that data should provide a better
assessment of Florence's intensity.

The upper-level outflow is becoming well established over the
cyclone, and the global model guidance indicates that Florence
will remain in a very favorable upper-level environment while the
cyclone moves over the warm waters over the southwestern
Atlantic.  These conditions favor strengthening with the only
apparent negative factor being nearby dry air, which will likely
remain away from the inner core due to the low shear conditions.
The NHC intensity forecast again calls for a period of rapid
strengthening within the next 12-36 hours, and Florence is forecast
to become a major hurricane on Monday with additional strengthening
early in the week.  This means that Florence is likely to be a very
powerful hurricane as it moves over the western Atlantic toward the
southeastern United States.  The new NHC intensity forecast is near
the various intensity consensus aids and is very similar to the
previous official forecast.

Florence is currently located between a couple of mid-level ridges
and a slow westward motion is expected today.  Another strong
high pressure ridge is forecast to build to the north of Florence
on Monday, which should cause the storm to begin moving
west-northwestward to northwestward at an increasingly faster
forward speed.  The dynamical model guidance is tightly clustered
for the first 2-3 days with increasing spread thereafter.  The GFS
remains along the right side of the guidance envelope with the HWRF
and ECMWF bracketing the left edge.  It should be noted that both
the GFS and ECMWF ensemble means are a little to the left or west
of their operational runs.  As a result, the NHC track forecast
lies to the left of the TVCA multi-model consensus, but is not as
far to the west as the FSSE and HCCA corrected consensus models at
day 5.  The models are in agreement that Florence is likely to slow
down near the end of the forecast period as a blocking high
pressure ridge builds to the north of the hurricane.

Key Messages:

1. Florence is forecast to be a dangerous major hurricane near the
southeast U.S. coast by late this week, and the risk of direct
impacts continues to increase. However, given the uncertainty in
track and intensity forecasts at those time ranges, it's too soon to
determine the exact timing, location, and magnitude of those
impacts.

2. Interests along the U.S. East Coast, particularly from north
Florida through North Carolina, should closely monitor the progress
of Florence, ensure they have their hurricane plan in place, and
follow any advice given by local officials.

3. Large swells affecting Bermuda and portions of the U.S. East
Coast will continue this week.  These swells will result in
life-threatening surf and rip currents.

FORECAST POSITIONS AND MAX WINDS

INIT  09/0900Z 24.5N  55.8W   60 KT  70 MPH
12H  09/1800Z 24.6N  56.7W   70 KT  80 MPH
24H  10/0600Z 24.8N  58.3W   85 KT 100 MPH
36H  10/1800Z 25.3N  60.4W  100 KT 115 MPH
48H  11/0600Z 26.1N  63.1W  110 KT 125 MPH
72H  12/0600Z 28.2N  69.1W  125 KT 145 MPH
96H  13/0600Z 31.3N  74.8W  120 KT 140 MPH
120H  14/0600Z 34.4N  77.9W  105 KT 120 MPH...INLAND

$$
Forecaster Brown

t02436

補一下21Z的C4評價，雖然03Z已經略為減弱到110節，但5天後仍看好重回115節強度。

ZCZC MIATCDAT1 ALL
TTAA00 KNHC DDHHMM

Hurricane Florence Discussion Number  26
NWS National Hurricane Center Miami FL       AL062018
500 PM AST Wed Sep 05 2018

Florence has continued to intensify during the day, with colder
cloud tops completely encircling a clearer eye. Both subjective and
objective Dvorak estimates have unanimously increased to T6.0/115
kt, and on this basis, the initial intensity is raised to 115 kt,
making Florence a category 4 hurricane.

Florence appears to be right along the southern edge of a zone of
stronger vertical shear and continues to defy the intensity
guidance, which has consistently been predicting weakening.  That
said, the last few satellite images indicate that the eye may be
becoming slightly disrupted by the shear.  Since the shear is
anticipated to increase during the next day or so, gradual weakening
is shown in the short-term official forecast, which lies along the
upper end of the guidance through 48 hours.  Beyond 48 hours,
vertical shear is anticipated to weaken, which would allow Florence
to intensify and potentially regain major hurricane status. However,
Florence will need to thread the needle between areas of stronger
shear for this to happen, and there is significant uncertainty in
the intensity forecast.  The new official intensity forecast is
little changed from before except to adjust upward to account for
the higher initial intensity.

The initial motion estimate remains northwestward, or 305/11 kt.
Strong upper-level ridging is forecast to strengthen north of
Florence over the next few days, forcing the hurricane to turn
toward the west-northwest through about 48 hours.  Track guidance is
good agreement during this period, and the official forecast is
essentially an update to the previous one.  Beyond day 2, a break
forms in the ridge, which results in a weakening of the steering
currents, a slowdown in Florence's forward speed, and a turn back
toward the northwest. The new official forecast is shifted south a
bit on days 3-5 to account for recent model trends and is closest to
the TVCN consensus.

It should be noted that there is considerable model ensemble spread
and run-to-run variability for Florence's track beyond day 5. Given
the large uncertainty at these time ranges, it is far too soon to
speculate what, if any, impacts Florence may have on the U.S. East
Coast next week. Regardless of Florence's eventual track, large
swells emanating from the hurricane will reach Bermuda beginning on
Friday, resulting in life-threatening surf and rip currents on the
island. Swells from Florence could also reach the U.S. East Coast by
early next week.

FORECAST POSITIONS AND MAX WINDS

INIT  05/2100Z 22.7N  46.6W  115 KT 130 MPH
12H  06/0600Z 23.5N  48.1W  110 KT 125 MPH
24H  06/1800Z 24.5N  49.7W  105 KT 120 MPH
36H  07/0600Z 25.2N  51.3W  100 KT 115 MPH
48H  07/1800Z 25.5N  52.9W   95 KT 110 MPH
72H  08/1800Z 26.0N  55.3W  100 KT 115 MPH
96H  09/1800Z 27.0N  57.4W  105 KT 120 MPH
120H  10/1800Z 29.0N  60.0W  105 KT 120 MPH

$$
Forecaster Berg/Rhome

NNNN

INIT  06/0300Z 23.4N  47.2W  110 KT 125 MPH
12H  06/1200Z 24.2N  48.4W  105 KT 120 MPH
24H  07/0000Z 25.0N  49.9W  100 KT 115 MPH
36H  07/1200Z 25.5N  51.6W   95 KT 110 MPH
48H  08/0000Z 25.7N  53.2W   95 KT 110 MPH
72H  09/0000Z 26.1N  55.7W  100 KT 115 MPH
96H  10/0000Z 27.2N  58.1W  105 KT 120 MPH
120H  11/0000Z 29.0N  62.0W  115 KT 130 MPH

霧峰追風者

18z 風眼清空，強度升四級颶風。

t02436

完全超乎預期的發展，15Z已經取得110節的評價。

150
WTNT41 KNHC 051440
TCDAT1

Hurricane Florence Discussion Number  25
NWS National Hurricane Center Miami FL       AL062018
1100 AM AST Wed Sep 05 2018

Remarkably, Florence has continued to strengthen.  The hurricane
has a compact central dense overcast with cold cloud tops completely
encircling a clear, well-defined eye.  With the improved structure,
subjective Dvorak estimates have increased to T5.5/102 kt from TAFB
and T6.0/115 kt from SAB, while the latest objective UW-CIMSS ADT
estimate is T5.8/110 kt.  The initial intensity is therefore set at
110 kt as a blend of these numbers, with Florence having become a
major hurricane earlier this morning.

Given the estimated maximum winds, Florence has been rapidly
intensifying since yesterday, an event that was not foreseen by any
intensity models, nor forecasters.  Diagnostics from the SHIPS
model and UW-CIMSS shear analyses have been consistently showing
southwesterly shear of 20-25 kt in the vicinity of Florence, but it
is possible that those schemes are averaging over a larger area
than might be reasonable given the hurricane's small size.  Florence
has apparently been able to find a small pocket of relatively low
shear, and with waters becoming progressively warmer, the hurricane
has strengthened significantly more than anticipated.  This makes
the intensity forecast incredibly uncertain.  SHIPS actually shows
the shear increasing over the next 24 hours, but global model
fields suggest that the hurricane may still be able to continue
within the protected pocket of lower shear for the next several
days.  As a result, the NHC official forecast keeps Florence's
intensity well above the available guidance, which all show the
hurricane weakening over the next day or two.  The new NHC
prediction follows this trend and also shows some weakening, but
this is a low-confidence forecast.  Either way, Florence is
expected to remain a hurricane throughout the 5-day period.

The track forecast also has its challenges.  The initial motion
estimate is northwestward, or 305/11 kt.  It now appears that
stronger upper-level ridging may take shape to the north of
Florence over the next few days, forcing the hurricane to turn back
toward the west-northwest from 36-72 hours.  After 72 hours, a
break in the ridge should allow Florence to turn back toward the
northwest, but the bulk of the track models have trended westward
since yesterday.  In light of these trends, the NHC official track
forecast has been shifted westward on days 4 and 5, but not quite
as far as the various model consensus aids.  It is worth stressing
that there is still a significant amount of spread among the GFS
and ECMWF ensemble members by the end of the forecast period, and
just like the intensity forecast, the track forecast is of low
confidence.


FORECAST POSITIONS AND MAX WINDS

INIT  05/1500Z 22.0N  45.7W  110 KT 125 MPH
12H  06/0000Z 22.7N  47.2W  110 KT 125 MPH
24H  06/1200Z 23.8N  49.0W  100 KT 115 MPH
36H  07/0000Z 24.7N  50.6W   95 KT 110 MPH
48H  07/1200Z 25.1N  52.1W   90 KT 105 MPH
72H  08/1200Z 25.7N  54.7W   90 KT 105 MPH
96H  09/1200Z 27.0N  57.0W   95 KT 110 MPH
120H  10/1200Z 28.5N  59.0W   95 KT 110 MPH

$$
Forecaster Berg/Rhome

霧峰追風者

12Z 強度升MH。

t02436

原本不怎麼看好發展，但03Z評價85節，06Z速報評價90節，站上C2。

797
WTNT41 KNHC 050252
TCDAT1

Hurricane Florence Discussion Number  23
NWS National Hurricane Center Miami FL       AL062018
1100 PM AST Tue Sep 04 2018

GOES-16 imagery shows that the eye of Florence has become better
defined during the last several hours, with even some mesovortices
in the eye present on the shortwave infrared channel.  Satellite
intensity estimates continue to rise, and the initial wind speed is
set to 85 kt, just below the latest TAFB estimate of 90 kt.

Florence remains on a west-northwestward course at 300/10 kt.  This
general course is expected to continue through 36 or 48 hours while
the hurricane remains near the southwestern edge of the subtropical
ridge.  After that time, the forecast becomes more uncertain,
depending on the presence of a narrow mid-level ridge over the
north-central Atlantic Ocean.  A look at the ensemble guidance
shows a bifurcation developing by day 5, with the ECMWF favoring
a more northward turn, and the UKMET ensembles showing a stronger
ridge and a continuation of a west-northwest track.  The new NHC
forecast is adjusted westward at long range, in line with the
corrected-consensus aids, but don't be surprised if this forecast
undergoes some large changes in the next few cycles, given the
split in the guidance.

This intensity forecast is also difficult.   Florence certainly has
exceeded expectations during the last day or so, with the hurricane
on the verge of rapidly intensifying during the last 24 hours
despite a marginal environment.  Some more strengthening is
called for in the short term to reflect the current trend.
However, the global models continue to insist that southwesterly
shear will increase over the next couple of days which, in
combination with considerable dry air aloft, should cause some
weakening.  Later tomorrow, a slow weakening trend should begin and
continue through 48 hours, although not weakening as much as shown
in the past advisory.  This can't be considered a high-confidence
prediction in light of what Florence has done so far.  On Friday, an
upper-level low could cut off to the south of the cyclone, which
would lessen the shear near Florence, and the hurricane should be
moving over steadily increasing SSTs. Restrengthening is forecast at
long range, and it wouldn't be surprising if the new NHC prediction
turns out to be too low.  It is best to be conservative, however,
since the track uncertainty is increasing by the end of the
forecast.


FORECAST POSITIONS AND MAX WINDS

INIT  05/0300Z 20.7N  43.9W   85 KT 100 MPH
12H  05/1200Z 21.5N  45.5W   90 KT 105 MPH
24H  06/0000Z 22.6N  47.6W   80 KT  90 MPH
36H  06/1200Z 23.7N  49.4W   70 KT  80 MPH
48H  07/0000Z 24.7N  50.9W   65 KT  75 MPH
72H  08/0000Z 26.0N  53.5W   65 KT  75 MPH
96H  09/0000Z 27.3N  55.8W   70 KT  80 MPH
120H  10/0000Z 29.0N  57.5W   80 KT  90 MPH

$$
Forecaster Blake

AL, 06, 2018090506,   , BEST,   0, 211N,  443W,  90,  976, HU,

t02436

15Z升C1，是大西洋今年第三個颶風

386
WTNT41 KNHC 041437
TCDAT1

Hurricane Florence Discussion Number  21
NWS National Hurricane Center Miami FL       AL062018
1100 AM AST Tue Sep 04 2018

Florence's structure has gradually increased in organization, with
SSMIS passes from a few hours ago revealing the development of a
mid-level microwave eye.  Dvorak estimates have responded in
kind--TAFB is up to T4.0, SAB is at T4.5, and the objective ADT is
in between at T4.4.  Since there still appears to be moderate
southwesterly shear inducing some tilt to the cyclone and
disrupting the infrared satellite pattern, the initial intensity is
raised conservatively to 65 kt, making Florence a hurricane.

The current motion remains west-northwestward, or 295/10 kt, with
Florence positioned near the southwestern edge of the subtropical
ridge.  The steering pattern ahead of Florence is rather complicated
and will be evolving over the next few days.  A large and complex
mid-/upper-level trough located northeast of the Leeward Islands is
expected to give way to the development of two upper-level highs
centered near the Greater Antilles and southwest of the Azores, with
Florence slowing down and turning northwestward between these new
features.  Despite this complex pattern, the spread in the track
models is less than normal, which increases the confidence in the
NHC track forecast for the next 5 days.  There is some spread which
begins to develop around day 5, with the ECMWF model moving Florence
a little faster toward the north while the GFS maintains a slower
speed and keeps the system to the south.  The updated NHC track
forecast has been nudged slightly to the east of the previous
forecast on days 4 and 5, close to the TVCX consensus but not as far
as the HCCA and ECMWF models.  There is still too much model spread
after day 5 to speculate what Florence might do beyond the official
forecast period.

Despite Florence becoming a hurricane, the southwesterly shear
affecting the cyclone is expected to increase over the next day or
two, which should prevent further intensification.  In fact, the
increasing shear, as well as mid-level relative humidities below 50
percent, should cause weakening between 24 and 72 hours.  After 72
hours, decreasing shear and warmer sea surface temperatures should
foster some re-intensification, with Florence expected to reattain
hurricane intensity by day 5.  The intensity guidance is in good
agreement, and the NHC forecast is very close to a blend of HCCA,
the Florida State Superensemble, and the ICON consensus.

FORECAST POSITIONS AND MAX WINDS

INIT  04/1500Z 19.7N  42.5W   65 KT  75 MPH
12H  05/0000Z 20.3N  44.0W   65 KT  75 MPH
24H  05/1200Z 21.3N  46.2W   65 KT  75 MPH
36H  06/0000Z 22.4N  48.2W   60 KT  70 MPH
48H  06/1200Z 23.6N  50.0W   55 KT  65 MPH
72H  07/1200Z 25.6N  52.7W   50 KT  60 MPH
96H  08/1200Z 27.5N  55.0W   55 KT  65 MPH
120H  09/1200Z 29.5N  56.5W   65 KT  75 MPH

$$
Forecaster Berg

t02436

命名Florence，巔峰上望60節。

081
WTNT41 KNHC 010856
TCDAT1

Tropical Storm Florence Discussion Number   8
NWS National Hurricane Center Miami FL       AL062018
500 AM AST Sat Sep 01 2018

A recent SSMIS microwave pass has revealed that the cyclone has
become much better organized with more pronounced convective
banding.  Satellite intensity estimates are wide ranging, spanning
from T1.5/25 kt from SAB to T3.4/53 kt from the UW-CIMSS ADT.  Since
the numbers overall have increased, and the structure has improved,
the initial intensity is raised to 35 kt, in closest agreement to
the TAFB estimate, but this could be conservative.  This makes the
depression Tropical Storm Florence, the sixth named storm of the
season.

Florence is moving west-northwestward, or 285/12 kt, and should
maintain this motion for the next 48 hours while traveling along the
southern periphery of the subtropical ridge.  After 48 hours, the
storm is expected to reach a break in the ridge, causing it to slow
down and turn northwestward by day 5.  The biggest change noted
among the track models on this cycle was a westward shift in the
overall guidance envelope.  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.

The environment is mixed with positives and negatives for Florence's
strengthening.  For the first 3 days, vertical shear over Florence
should be quite low, but the cyclone will also be moving through a
less-than-ideal thermodynamic environment with marginal sea surface
temperatures and decreasing mid-level moisture.  After 3 days, the
thermodynamic environment should begin to improve, but then the
shear is forecast to strengthen. These conflicting signals point to
only gradual strengthening, and the suite of intensity models aren't
too far off from one another, nor from the previous NHC forecast.
For that reason, no significant changes were made in this forecast
package.

FORECAST POSITIONS AND MAX WINDS

INIT  01/0900Z 14.5N  26.7W   35 KT  40 MPH
12H  01/1800Z 15.0N  28.7W   40 KT  45 MPH
24H  02/0600Z 15.7N  31.2W   45 KT  50 MPH
36H  02/1800Z 16.4N  33.7W   50 KT  60 MPH
48H  03/0600Z 17.1N  36.3W   55 KT  65 MPH
72H  04/0600Z 18.7N  41.4W   60 KT  70 MPH
96H  05/0600Z 21.0N  45.5W   60 KT  70 MPH
120H  06/0600Z 23.5N  48.5W   55 KT  65 MPH

$$
Forecaster Berg