霧峰追風者

  熱帶風暴
編號：14 L
名稱：Lee

  基本資料  
擾動編號日期：2017 年 09 月 22 日 23 時
命名日期　　：2017 年 09 月 23 日 05 時
撤編日期　　：2017 年 09 月 00 日 00 時
登陸地點　　：暫無

  巔峰時期資料  
近中心最強風速
國家颶風中心(NHC)：35 kts
海平面最低氣壓：1009 毫巴

  過去路徑圖  

  擾動編號資料  
98L-INVEST-25kts-1016mb-29.9N-49W

NHC : 30%

1. Updated:  A small area of low pressure has developed over the
central Atlantic Ocean almost a thousand miles east-southeast of
Bermuda.  The low is producing a concentrated area of showers and
thunderstorms, although the circulation appears somewhat elongated.
Some additional development of this system is possible during the
next few days while it moves slowly northward through early next
week.
* Formation chance through 48 hours...low...30 percent.
* Formation chance through 5 days...medium...40 percent

以上資料來自：NHC、颱風論壇整理製作

霧峰追風者

NHC展望提升至40%

1. A small area of low pressure, associated with the remnants of Lee,
is located over the central Atlantic Ocean almost a thousand miles
east-southeast of Bermuda.  The low is producing a concentrated area
of showers and thunderstorms, although the circulation appears
somewhat elongated.  Some additional development of this system is
possible during the next few days while it moves slowly northward
through early next week.
* Formation chance through 48 hours...medium...40 percent.
* Formation chance through 5 days...medium...50 percent.

霧峰追風者

判定是同一個系統，Lee 21Z再次開始發報，環流迷你，逐漸增強，巔峰上看60kt.在請版主合併處理。

ZCZC MIATCDAT4 ALL
TTAA00 KNHC DDHHMM

Tropical Depression Lee Discussion Number  18
NWS National Hurricane Center Miami FL       AL142017
500 PM AST Fri Sep 22 2017

The mid-level circulation from Lee separated from the low-level
center two days ago and moved northward around the eastern
periphery of a large upper-level trough.  A large convective burst
over the mid-level center yesterday then caused a new low-level
center to develop while it moved on the northern side of the upper
trough. ASCAT and ship data indicate that the small circulation is
now well defined, and since deep convection has persisted near the
center, advisories on Lee are being restarted. The initial wind
speed is 30 kt, which could be conservative given the healthy
structure seen on the last-light visible and recent microwave data.

Cold upper-level temperatures from the upper trough should mitigate
the effect of marginally warm waters for the next few days while Lee
remains in a low-shear environment.  The depression is expected to
strengthen over the next few days until westerly shear is forecast
to increase. The official forecast is similar to the model guidance,
although it shows an earlier peak more coincident with the
lower-shear, warmer-water environment.  This wind speed forecast is
difficult because Lee is a very small tropical cyclone, which
notoriously have rapid changes, both up and down, in intensity.

Lee is moving northward at about 6 kt.  The depression should turn
to the northeast and east over the next couple of days while it
moves around a ridge over the tropical central Atlantic.  Lee is
forecast to become trapped beneath a mid-latitude ridge in a few
days, which should cause the cyclone to drift at long range.  It
should be noted that models have a rather weak representation of
Lee at the present time, which causes this to be an uncertain
forecast.  For now, the forecast is closest to the ECMWF, which
has the most coherent cyclone to follow.


FORECAST POSITIONS AND MAX WINDS

INIT  22/2100Z 30.8N  48.9W   30 KT  35 MPH
12H  23/0600Z 31.7N  48.7W   40 KT  45 MPH
24H  23/1800Z 32.3N  48.2W   45 KT  50 MPH
36H  24/0600Z 32.3N  47.2W   50 KT  60 MPH
48H  24/1800Z 32.1N  45.8W   55 KT  65 MPH
72H  25/1800Z 31.4N  43.2W   60 KT  70 MPH
96H  26/1800Z 30.5N  42.0W   55 KT  65 MPH
120H  27/1800Z 29.5N  43.0W   50 KT  60 MPH

$$
Forecaster Blake

NNNN

霧峰追風者

NHC 03Z重回TS，巔峰上看一級颶風，預估路徑緩慢東移後在西折。

ZCZC MIATCDAT4 ALL
TTAA00 KNHC DDHHMM

Tropical Storm Lee Discussion Number  19
NWS National Hurricane Center Miami FL       AL142017
1100 PM AST Fri Sep 22 2017

Several microwave overpasses between 2100 and 2200 UTC indicated
that Lee was becoming better organized, at least at the mid-levels.
In particular, a WindSat overpass near 21Z indicated that a
mid-level eye was already forming.  Since that time, however, cloud
tops have warmed, the CDO has shrunk, and a GPM overpass around 0100
UTC showed that most of the convection is currently confined to the
southeast semicircle of the tropical storm. The UW-CIMSS ADT
supports an intensity of 35 kt, and the TAFB Dvorak analyst
indicated that the subjective classification would have been higher,
if the technique wasn't constrained by the fact that classifications
on Lee only recently restarted.  Based on these data, the initial
intensity has been increased to 35 kt.

The intensity forecast for Lee is highly uncertain.  The tropical
storm is very small, and small cyclones often quickly strengthen or
weaken.  Furthermore, Lee is small enough that some of our models
(and many of our observing platforms) may have trouble resolving the
inner core of the storm.  Given the current convective state of Lee,
significant strengthening in the short term seems unlikely.
However, the cyclone is expected to be in a fairly unstable, low
shear environment for at least the next 3 days, so it is possible
that rapid intensification could occur at some time during that
period.  On the other hand, I can't rule out that the cyclone could
dissipate entirely, as depicted by the GFS, within a couple days.
For now, my forecast is closest to the HWRF for the first 72 h,
since that model tends to do well in low-shear environments and
should have sufficient resolution to model Lee's core.  After that
time, the forecast is close to the HCCA and IVCN intensity consensus
models.

Lee has continued to move north around 6 kt.  Little change has been
made to the track forecast, and Lee is still forecast to move around
a subtropical ridge for the next 72 h.  At days 4 and 5, a ridge
building between Lee and Maria to the west should cause a turn more
toward the south, as long as Lee is sufficiently deep to be steered
by that feature.  The forecast continues to be close to the ECMWF,
since it is still the global model with the strongest representation
of Lee, in line with the NHC forecast.

FORECAST POSITIONS AND MAX WINDS

INIT  23/0300Z 31.5N  49.0W   35 KT  40 MPH
12H  23/1200Z 32.2N  48.5W   40 KT  45 MPH
24H  24/0000Z 32.5N  47.8W   45 KT  50 MPH
36H  24/1200Z 32.4N  46.6W   50 KT  60 MPH
48H  25/0000Z 32.1N  45.2W   60 KT  70 MPH
72H  26/0000Z 31.3N  43.1W   75 KT  85 MPH
96H  27/0000Z 30.0N  42.5W   75 KT  85 MPH
120H  28/0000Z 29.5N  43.5W   65 KT  75 MPH
$$
Forecaster Zelinsky
NNN

開梅

大西洋的颶風經常出產這種規模小小的，環流也不大的緊實颱風，即使是五級颶風，近年來觀察好像也比西太五級颱風迷你些

霧峰追風者

速報升一級颶風，風眼開啟....

t02436

NHC加發特報，升格颶風。

000
WTNT34 KNHC 240624
TCPAT4

BULLETIN
Hurricane Lee Special Advisory Number  24
NWS National Hurricane Center Miami FL       AL142017
200 AM AST Sun Sep 24 2017

...LEE RAPIDLY STRENGTHENS INTO A HURRICANE...


SUMMARY OF 230 AM AST...0630 UTC...INFORMATION
----------------------------------------------
LOCATION...31.9N 50.1W
ABOUT 860 MI...1385 KM E OF BERMUDA
ABOUT 1370 MI...2205 KM W OF THE AZORES
MAXIMUM SUSTAINED WINDS...75 MPH...120 KM/H
PRESENT MOVEMENT...STATIONARY
MINIMUM CENTRAL PRESSURE...987 MB...29.15 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.


DISCUSSION AND 48-HOUR OUTLOOK
------------------------------
At 230 AM AST (0630 UTC), the center of Hurricane Lee was located
near latitude 31.9 North, longitude 50.1 West. Lee is currently
stationary.  A drift toward the southeast is expected to begin
later today.

Maximum sustained winds have increased to near 75 mph (120 km/h)
with higher gusts.  Additional strengthening is forecast during the
next 36 to 48 hours.

Lee is a small hurricane.  Hurricane-force winds extend outward up
to 10 miles (20 km) from the center and tropical-storm-force winds
extend outward up to 35 miles (55 km).

The estimated minimum central pressure is 987 mb (29.15 inches).


HAZARDS AFFECTING LAND
----------------------
None.


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

$$
Forecaster Beven

霧峰追風者

強度升二級颶風，還有小幅度增強空間，預計2天後加速北上。

ZCZC MIATCDAT4 ALL
TTAA00 KNHC DDHHMM

Hurricane Lee Discussion Number  33
NWS National Hurricane Center Miami FL       AL142017
500 AM AST Tue Sep 26 2017

Lee's cloud pattern has continued to become better organized this
evening.  The eye has cleared out and has warmed to nearly 10
degrees Celsius, and the eye wall cloud tops have cooled to
-63 degrees Celsius.  The initial intensity is increased modestly to
85 kt and is based on a blend of the subjective and objective Dvorak
T-numbers.  It is worth noting that the ADT adjusted raw T-number
yields an estimated intensity of 97 kt based on an eye scene-type.

The previously noted southeasterly shear undercutting the diffluent
flow aloft has certainly diminished and should remain low for the
next 48 hours or so.  During this initial period, Lee could get a
little stronger as indicated in the HWRF hurricane model and the
Decay-SHIPS.  Afterward, increasing vertical shear, primarily due to
the outflow generated by Maria, and decreasing sea surface
temperatures should induce a gradual weakening trend as the cyclone
moves into a high latitude baroclinic zone and ultimately becomes an
extratropical cyclone in 4 days.  The intensity forecast is
basically an update of 6 hours ago, and follows an average of the
IVCN and Florida State Superensemble guidance.

The initial motion is estimated to be westward, or 260/9 kt.  The
cyclone is expected to continue moving within the easterly mid-level
steering flow, produced by a relatively narrow mid-tropospheric
ridge situated to the north, during the next 24 hours.  Afterward,
a combination of a broad mid- to upper-level shortwave trough moving
out of the eastern Canadian Provinces and a subtropical ridge
building east of Lee should steer the hurricane gradually
northwestward and northward.  On day 3 and beyond,  Lee is forecast
to accelerate northeastward as it becomes embedded in a deep-layer
high latitude southwesterly flow downstream from the aforementioned
shortwave trough.  Global models and the Cyclone Phase Evolution
analysis/forecast product show Lee become a extratropical
cyclone no later than day 4.  The NHC forecast track is a little
south of the previous one through 48 hours, but similar
thereafter, and is based on the TVCX and HCCA consensus models.

FORECAST POSITIONS AND MAX WINDS

INIT  26/0900Z 30.0N  52.5W   85 KT 100 MPH
12H  26/1800Z 29.9N  53.9W   90 KT 105 MPH
24H  27/0600Z 30.2N  55.4W   90 KT 105 MPH
36H  27/1800Z 30.9N  56.4W   90 KT 105 MPH
48H  28/0600Z 32.2N  56.6W   85 KT 100 MPH
72H  29/0600Z 36.9N  53.0W   75 KT  85 MPH
96H  30/0600Z 44.5N  40.2W   60 KT  70 MPH...POST-TROP/EXTRATROP
120H  01/0600Z 50.9N  22.0W   50 KT  60 MPH...POST-TROP/EXTRATROP

$$
Forecaster Roberts

NNNN