老農民版夜神月

  三級颶風  
編號：09 L
名稱：Humberto

  基本資料  
擾動編號日期：2019 年 09 月 11 日 03 時
命名日期　　：2019 年 09 月 14 日 11 時
撤編日期　　：2019 年 09 月 00 日 00 時
登陸地點　　：無

  巔峰時期資料  
近中心最強風速 ：110 kt
海平面最低氣壓 ：951 百帕

  過去路徑圖  

  擾動編號資料  
95L INVEST 190910 1800 22.0N 72.0W ATL 20 1013


  NHC：10%  

1. Shower and thunderstorm activity associated with a surface trough
near the southeastern Bahamas and adjacent Atlantic waters has
increased since yesterday. Limited development of this disturbance
is expected during the next couple of days while it moves
west-northwestward across the Bahamas. However, environmental
conditions could become a little more conducive for development when
the system moves over the Florida Straits and the Gulf of Mexico
late this week and this weekend. Regardless of development, this
disturbance will produce periods of locally heavy rainfall across
the Bahamas through Thursday, and across Florida on Friday and
continuing into the weekend.
* Formation chance through 48 hours...low...10 percent.
* Formation chance through 5 days...low...30 percent.

以上資料來自：NHC、颱風論壇整理製作

老農民版夜神月

NHC展望提升至Medium,40%/60%

1. A large area of showers and thunderstorms was located along a
sharp surface trough from near eastern Cuba through the southeastern
Bahamas into the southwestern Atlantic. Conditions are forecast to
become more favorable for development late this week, and a tropical
depression could form near the northwestern Bahamas or South Florida
as early as Friday. Further development is possible over the eastern
Gulf of Mexico later this weekend. The disturbance will likely
produce periods of locally heavy rainfall and gusty winds across the
Bahamas through Friday, and across Florida during the weekend.
* Formation chance through 48 hours...medium...40 percent.
* Formation chance through 5 days...medium...60 percent.

老農民版夜神月

NHC展望提升至High,70%/80%

1. Satellite images indicate that the area of disturbed weather over
the central and southeastern Bahamas is gradually becoming better
organized while surface pressures are falling in the area.
Conditions are becoming favorable for a tropical depression or a
tropical storm to form within the next day or so as the system moves
toward the northwest through the northwestern Bahamas and toward
the Florida Peninsula at 5 to 10 mph. If this development trend
continues Potential Tropical Cyclone advisories will likely be
initiated later today. This disturbance will bring heavy rainfall
and gusty winds across portions of the Bahamas through Friday,
especially in portions of the northwestern Bahamas affected by
Hurricane Dorian. An Air Force Reserve reconnaissance aircraft is
scheduled to investigate the system this afternoon, if necessary.
* Formation chance through 48 hours...high...70 percent.
* Formation chance through 5 days...high...80 percent.

老農民版夜神月

NHC12/21Z判定95L為潛在熱帶氣旋,並預測將侵襲美國東南沿岸

494
WTNT44 KNHC 122046
TCDAT4

Potential Tropical Cyclone Nine Discussion Number   1
NWS National Hurricane Center Miami FL       AL092019
500 PM EDT Thu Sep 12 2019

The disturbance in the southeastern Bahamas has not developed a
closed circulation yet, but the cloud pattern is gradually becoming
better organized. An Air Force plane is currently approaching the
disturbance, and will give NHC more details on the structure of the
system. Advisories are being initiated on this system as a
Potential Tropical Cyclone to allow for the issuance of a tropical
storm warning for a portion of the northwest Bahamas after
consultation with the meteorological service of that country.

The system is still under the influence of strong shear caused by an
upper-level low in the Gulf of Mexico. As the disturbance moves away
from the upper low, conditions are expected to be a little more
conducive for development as indicated in the intensity forecast.
With the exception of the GFS, which forecasts a vigorous trough
crossing Florida into the Gulf of Mexico, the remainder of the
global models develop a tropical cyclone near the northwestern
Bahamas and move it as an intensifying system very close to the east
coast of Florida. The NHC forecast opted for the solution of these
latter models, however, it is emphasized that given the model
discrepancy, both the track and intensity forecasts are highly
uncertain, more than usual I would say.

Key Messages:

1. The disturbance is expected to become a tropical storm and bring
tropical storm force winds to portions of the northwest Bahamas
within 36 hours. As a result, advisories have been initiated on
Potential Tropical Cyclone Nine. Note that forecast uncertainty for
these disturbances is generally larger than for tropical cyclones,
especially beyond 48-72 hours.

2. The system is expected to bring tropical-storm-force winds and
heavy rainfall to portions of the northwest Bahamas on Friday and
Saturday. Significant storm surge is not expected in the northwest
Bahamas from this system. Residents there should follow any advice
given by local officials.

3. The system could bring tropical-storm-force winds and rainfall
to portions of the Florida east coast over the weekend. Residents
there should monitor the progress of this system.


FORECAST POSITIONS AND MAX WINDS

INIT  12/2100Z 23.7N  74.8W   25 KT  30 MPH...POTENTIAL TROP CYCLONE
12H  13/0600Z 24.5N  76.0W   25 KT  30 MPH
24H  13/1800Z 25.5N  77.2W   30 KT  35 MPH...TROPICAL CYCLONE
36H  14/0600Z 26.5N  78.9W   40 KT  45 MPH
48H  14/1800Z 27.5N  80.2W   45 KT  50 MPH
72H  15/1800Z 30.0N  82.0W   30 KT  35 MPH...INLAND
96H  16/1800Z 31.0N  82.0W   25 KT  30 MPH...INLAND
120H  17/1800Z 31.5N  80.0W   30 KT  35 MPH...OVER WATER

$$
Forecaster Avila

老農民版夜神月

NHC13/21Z升格09L為TD,預計將在美國東南外海進行轉向,強度上望75節不封頂

000
WTNT44 KNHC 132043
TCDAT4

Tropical Depression Nine Discussion Number   5
NWS National Hurricane Center Miami FL       AL092019
500 PM EDT Fri Sep 13 2019

An Air Force plane extensively investigated the disturbance near the
Bahamas during the past several hours, and in the last portion of
the mission, the crew was able to locate a center of circulation,
although weak, near the convection.  The center was a little bit
to the east of the previous estimates. Satellite images also
indicate that the cloud pattern has become a little better organized
and Dvorak estimates are T2.0 and 1.5 from TAFB and SAB,
respectively. On this basis, the disturbance has been classified as
a tropical depression with 25 kt winds.

Conditions are not ideal for strengthening since the depression
is still embedded within a moderate shear environment, but
this parameter is not expected to be strong enough to halt
additional development. The NHC forecast still calls for this system
to become a tropical storm on Saturday with gradual intensification
thereafter.  Global models insist on further development, and the
reliable guidance suggests that the cyclone could even reach
hurricane intensity in about 3 days, and so does the NHC forecast.
By then, the system is expected to be over the Atlantic waters well
southeast of the coast of the Carolinas.

Due to the reformation of the apparent center, the initial motion is
highly uncertain. The best estimate is toward the northwest or 305
degrees at 7 kt.   A weakness in the ridge over the western Atlantic
is forecast to develop, and this pattern should steer the system
slowly toward the northwest and then northward. In about 3 days, an
eastward moving mid-latitude trough will force the system to recurve
away from the coast toward the Atlantic.  The track guidance has
shifted to the east again, and this shift is larger due to the
eastward formation of the center. Consequently, the NHC track
forecast was adjusted in that direction, but it remains on the
western edge of the guidance envelope.

Key Messages:

1. The depression is forecast to become a tropical storm within
the next 24 hours and will likely bring tropical-storm-force winds
and heavy rainfall to portions of the northwestern Bahamas later
today and Saturday. Significant storm surge is not expected in the
northwest Bahamas from this system. Residents there should follow
any advice given by local officials.

2. The system could still bring tropical storm conditions to
portions of the Florida east coast. Residents there should monitor
the progress of this system and follow any advice given by local
officials.

3. Heavy rainfall and scattered flash flooding is possible this
weekend in coastal sections of eastern Florida, Georgia, and South
Carolina. The chance of heavy rainfall affecting coastal North
Carolina early next week continues to diminish.


FORECAST POSITIONS AND MAX WINDS

INIT  13/2100Z 25.6N  75.0W   25 KT  30 MPH
12H  14/0600Z 26.2N  76.0W   30 KT  35 MPH
24H  14/1800Z 27.4N  77.6W   35 KT  40 MPH
36H  15/0600Z 28.8N  78.5W   45 KT  50 MPH
48H  15/1800Z 30.0N  78.8W   55 KT  65 MPH
72H  16/1800Z 31.5N  76.5W   65 KT  75 MPH
96H  17/1800Z 32.0N  73.0W   70 KT  80 MPH
120H  18/1800Z 32.5N  68.0W   75 KT  85 MPH

$$
Forecaster Avila

老農民版夜神月

實測支持,NHC14/03Z升格09L為TS,命名Humberto

000
WTNT44 KNHC 140300 CCA
TCDAT4

Tropical Storm Humberto Discussion Number   6...Corrected
NWS National Hurricane Center Miami FL       AL092019
1100 PM EDT Fri Sep 13 2019

Corrected to change depression to storm in the second paragraph

Deep convection has been gradually increasing this evening, and it
is currently most organized in a curved band to the east of the
estimated center.  In addition, data from the NOAA Hurricane Hunters
indicate that the depression has strengthened.  The maximum
flight-level wind at 700 mb was 41 kt and reliable SFMR values were
35 kt.  Based on that data, the initial intensity is increased to 35
kt, making the cyclone Tropical Storm Humberto.  The data from the
aircraft indicate that the cyclone is titled to the northeast with
height, likely due to southwesterly wind shear.

Humberto has been moving erratically during the past 12 to 18 hours
as the cyclone has been trying to organize, but my best guess at the
initial motion is 320/5. During the next few days, a ridge to the
north of the system over the eastern United States and the western
Atlantic is expected to slide southeastward, with a weakness in the
ridge developing due to a mid- to upper-level trough over the
northeastern U.S.  This change in the steering pattern should cause
the storm to slow down and turn northward off the east coast of
Florida in 36 to 48 hours.  The models show the trough over the
northeastern U.S. amplifying early next week, which should cause
Humberto to turn northeastward and then eastward away from the U.S.
The NHC track forecast has been nudged south and east of the
previous one to be in better agreement with the latest consensus
models. Since there is increasing confidence that the storm will
remain well offshore of the coast of Florida, the Tropical Storm
Watch for that area has been discontinued.

The storm is still feeling some effects of southwesterly shear
and drier air, which is causing its lopsided appearance in
satellite images and strong tilt in the aircraft data.  The
atmospheric conditions are expected to gradually become more
conducive for strengthening while Humberto moves over the warm
Gulf Stream waters.  These environmental parameters support
intensification, and the cyclone is expected to become a hurricane
in 2 to 3 days.  The NHC intensity forecast is largely an update of
the previous one and in line with the HCCA and IVCN guidance.

Key Messages:

1. Humberto will likely bring tropical-storm-force winds and heavy
rainfall to portions of the northwestern Bahamas on Saturday.
Significant storm surge is not expected in the northwest Bahamas
from this system. Residents there should follow any advice given by
local officials.

2. Heavy rainfall and scattered flash flooding is possible this
weekend in coastal sections of eastern Florida, Georgia, and South
Carolina. The chance of heavy rainfall affecting coastal North
Carolina early next week continues to diminish.


FORECAST POSITIONS AND MAX WINDS

INIT  14/0300Z 25.6N  75.2W   35 KT  40 MPH
12H  14/1200Z 26.5N  76.5W   35 KT  40 MPH
24H  15/0000Z 27.6N  77.6W   40 KT  45 MPH
36H  15/1200Z 28.8N  78.2W   50 KT  60 MPH
48H  16/0000Z 29.8N  78.1W   60 KT  70 MPH
72H  17/0000Z 31.0N  75.5W   70 KT  80 MPH
96H  18/0000Z 31.3N  72.0W   75 KT  85 MPH
120H  19/0000Z 32.3N  67.2W   75 KT  85 MPH

$$
Forecaster Cangialosi

老農民版夜神月

NHC16/03Z升格Humberto為一級颶風,預報72小時內強度尚有逐漸增強的趨勢,巔峰上看95KT

WTNT44 KNHC 160237
TCDAT4

Hurricane Humberto Discussion Number  14
NWS National Hurricane Center Miami FL       AL092019
1100 PM EDT Sun Sep 15 2019

700 mb flight-level wind data from a NOAA P-3 Hurricane Hunter
aircraft investigating Humberto indicate that the system's intensity
is now 65 kt.  This is also supported by Dvorak classifications
from TAFB and SAB, and it makes the cyclone the third hurricane of
the 2019 Atlantic season.  Humberto's cloud pattern has continued to
gradually become better organized, with increasing coverage and
intensity of deep convection, and pronounced upper-level outflow
over the eastern semicircle of the circulation. The hurricane is
expected to traverse warm Gulf Stream waters for the next several
days, but the dynamical models forecast a significant increase in
southwesterly vertical shear through 72 hours.  In spite of the
latter unfavorable factor, the numerical guidance generally shows
intensification. This is likely at least partially due to some
baroclinic forcing caused by a strong mid-latitude trough to the
north and northeast of Humberto.  The official forecast is a blend
of the latest simple and corrected consensus models and is very
similar to the previous one.

Humberto continues to move very slowly and the latest aircraft and
satellite center fixes indicate that the motion is now
northeastward or 040/3 kt.  The hurricane has just rounded the
western periphery of a subtropical anticyclone and steering
currents are likely to remain weak for the next couple of days.  An
east-northeastward track with a very gradual increase in forward
speed is expected for much of the period while Humberto moves
between the subtropical high and stronger westerlies associated with
the trough to the north.  The new NHC track forecast is a little
slower than the previous one in 4-5 days, but not as slow as the
latest ECMWF and GFS global model runs.

Large swells from Humberto will affect portions of the northwestern
Bahamas and southeastern United States coast during the next few
days.  These swells are expected to produce dangerous surf
conditions and life-threatening rip currents.  See products issued
by your local weather office for additional information.


FORECAST POSITIONS AND MAX WINDS

INIT  16/0300Z 29.4N  77.6W   65 KT  75 MPH
12H  16/1200Z 29.8N  77.1W   70 KT  80 MPH
24H  17/0000Z 30.1N  76.0W   75 KT  85 MPH
36H  17/1200Z 30.5N  74.7W   80 KT  90 MPH
48H  18/0000Z 30.8N  73.0W   85 KT 100 MPH
72H  19/0000Z 31.8N  68.3W   95 KT 110 MPH
96H  20/0000Z 35.0N  63.3W   80 KT  90 MPH
120H  21/0000Z 39.0N  60.0W   60 KT  70 MPH

$$
Forecaster Pasch

老農民版夜神月

NHC18/15Z報,Humberto升格二級颶風,並持續預測24H~36H巔峰時將達95節,距離成為北大西洋今年第二個MH只有一步之遙

WTNT44 KNHC 171458
TCDAT4

Hurricane Humberto Discussion Number  20
NWS National Hurricane Center Miami FL       AL092019
1100 AM EDT Tue Sep 17 2019

An Air Force Reserve reconnaissance aircraft that investigated
Humberto earlier this morning found 700-mb flight-level winds of 96
kt and 82-kt surface winds on a dropsonde in the southwestern
quadrant, and 81-kt SFMR surface winds in the northwestern quadrant.
More importantly, the wind data indicate that Humberto's wind field
has expanded significantly and is becoming asymmetric with the
largest wind radii now located in the southern semicircle. The
aircraft also measured a central pressure of 961 mb, down 18 mb
since this time yesterday. The central pressure typically
corresponds to an intensity of around 100 kt, but the expansion of
the wind field has resulted in little increase in the eyewall wind
field for now. Based on these data, the initial intensity has been
increased to 85 kt.

Humberto has maintained an east-northeastward motion of 075/07 kt.
The hurricane is forecast to remain embedded within the mid-latitude
westerlies though the forecast period. A deep-layer trough is
forecast to dig southward to the west of Humberto in the 24-48 hour
period, causing the hurricane to gradually gain latitude and pass
just to the northwest of Bermuda in around 36 hours. The models are
in excellent agreement on this developing track scenario and are
tightly clustered around the previous advisory track. However, the
recent expansion of the wind field and the expected additional
increase in the wind on the southeast side of Humberto's circulation
will result in the island being in near-hurricane-force conditions.
By 72 hours and beyond, Humberto will accelerate northeastward
over the cold waters of the north Atlantic and interact with a
strong frontal system, resulting in the transition into a large
extratropical low. The official track forecast is similar to the
previous advisory track through 48 hours, and then is a little
faster in the 72-120 hour period, close to a blend of the various
consensus models.

Due to the expansion of Humberto's wind field and large 35-40-n mi
wide eye, only modest strengthening is expected during the next 36
hours or so. Although not explicitly shown, Humberto could still
become a major hurricane between 24-36 hours when the cyclone will
be located over the warmest water of about 29C. Thereafter,
gradual wakening is forecast due to cooler waters and strong
southwesterly vertical wind shear in excess of 40 kt. However, the
typical rate of weakening due to such hostile shear conditions will
be tempered owing to the increasing baroclinic forcing in the
right-rear entrance region of a polar jet maximum. The new intensity
forecast is nearly identical to the previous advisory, and follows a
blend of the consensus models HCCA and FSSE.

Key Messages:

1. Tropical-storm-force winds are expected to reach Bermuda by
Wednesday afternoon, with hurricane conditions possible Wednesday
night and Thursday morning. Residents there should follow advice
given by local officials.

2. Large swells will increase along the coast of Bermuda by
Wednesday. Dangerous breaking waves, especially along south-facing
beaches, could cause coastal flooding Wednesday night and Thursday.

3. Swells will continue to affect the northwestern Bahamas and the
southeastern coast of the United States from east-central Florida to
North Carolina during the next couple of days, creating life-
threatening surf and rip current conditions.

FORECAST POSITIONS AND MAX WINDS

INIT  17/1500Z 30.7N  73.5W   85 KT 100 MPH
12H  18/0000Z 31.1N  72.0W   90 KT 105 MPH
24H  18/1200Z 31.8N  69.4W   95 KT 110 MPH
36H  19/0000Z 33.1N  66.1W   95 KT 110 MPH
48H  19/1200Z 35.3N  62.6W   90 KT 105 MPH
72H  20/1200Z 39.6N  58.4W   70 KT  80 MPH
96H  21/1200Z 43.0N  52.2W   60 KT  70 MPH...POST-TROP/EXTRATROP
120H  22/1200Z 44.5N  40.0W   50 KT  60 MPH...POST-TROP/EXTRATROP

$$
Forecaster Stewart