周子堯@FB

周子堯@FB 發表於 2020-8-20 22:45
15Z，NHC升格14L

Special Message from NHC        Issued 20 Aug 2020 14:17 UTC   

NHC will initiate advisories on Tropical Depression Fourteen, located in the Caribbean Sea, at 11 AM EDT (1500 UTC).

老農民版夜神月

NHC15Z升格其為14L,初報上望60KT

046
WTNT44 KNHC 201456
TCDAT4

Tropical Depression Fourteen Discussion Number   1
NWS National Hurricane Center Miami FL       AL142020
1100 AM EDT Thu Aug 20 2020

Visible satellite images indicate that the area of disturbed
weather moving across the central Caribbean Sea has developed a
closed surface circulation, with the center embedded beneath
cellular convective cells and a large cirrus canopy.  Also,
convection has increased in organization, and TAFB and SAB have
given the system classification of T2.0/30 kt and T1.5/25 kt,
respectively.  Therefore, advisories are being initiated on
Tropical Depression Fourteen with maximum winds of 30 kt.  An
expected ASCAT pass later today and an Air Force Reserve Hurricane
Hunter mission scheduled for this afternoon should give us a better
handle on both the depression's center location and its maximum
winds.

The depression continues to move westward at a pretty good clip,
currently estimated to be on a heading of 280 degrees at 18 kt.  
This motion is being driven by the western extent of the Bermuda
high, which currently noses into the northwestern Caribbean Sea.  
However, a deep-layer trough over the Gulf of Mexico is expected to
become the main driver in the coming days, causing the cyclone to
slow down and turn rather suddenly toward the west-northwest and
northwest in the next 24-36 hours.  A general northwestward motion
should then continue until the end of the 5-day forecast period,
bringing the system across the Yucatan Peninsula Saturday night and
into the central and western Gulf of Mexico early next week.  Most
of the reliable track models are clustered close to one another,
and the official NHC track forecast is therefore very close to the
multi-model consensus aids, including the HCCA model.

Once the depression slows down during the next 24-36 hours,
environmental conditions appear ideal for strengthening.  The
magnitude of vertical shear is expected to be less than 10 kt for
at least the next 2 days, while the system will be moving over the
deep, warm waters of the northwestern Caribbean Sea, where sea
surface temperatures are 29-30 degrees Celsius.  Given these
conditions, some of the intensity guidance actually appears more
muted than I would have expected, and I have therefore elected to
closely follow the SHIPS and LGEM models, which are near the upper
end of the guidance envelope.  It is possible that the depression
could be near or at hurricane strength when it approaches the
Yucatan Peninsula of Mexico in 2-3 days.  Some weakening is
anticipated when the center moves over land, and then
re-strengthening is likely after it moves over the Gulf of Mexico.  
There will be an increase in shear over the Gulf in 4-5 days, and
right now there is greater-than-normal uncertainty in how this will
affect the cyclone's intensity at that point.  For now, the
official forecast on days 4 and 5 shows a flat-lined intensity, and
this scenario lies a little above the ICON intensity consensus and
the HCCA model solution.

Key Messages:

1. Tropical Depression Fourteen is expected to strengthen over the
northwestern Caribbean Sea through Saturday, and it could produce
tropical-storm-force winds and heavy rainfall over portions of the
coast of Honduras and the Bay Islands beginning tonight through
Friday.  The system could be near or at hurricane strength when it
reaches the Yucatan Peninsula of Mexico late Saturday, and watches
could be required for a portion of that area later today.

2. The system is expected to move into the south-central Gulf
of Mexico as a tropical storm on Sunday.  Some strengthening is
anticipated while it moves northwestward over the western Gulf of
Mexico early next week, but it is too soon to know exactly how
strong it will get or the location and magnitude of impacts it
will produce along the central or northwestern Gulf Coast.  
Interests in that area should continue monitoring the progress of
this system over the next few days.

FORECAST POSITIONS AND MAX WINDS

INIT  20/1500Z 15.1N  79.7W   30 KT  35 MPH
12H  21/0000Z 15.5N  81.9W   35 KT  40 MPH
24H  21/1200Z 16.3N  84.2W   40 KT  45 MPH
36H  22/0000Z 17.1N  85.5W   50 KT  60 MPH
48H  22/1200Z 18.4N  86.4W   55 KT  65 MPH
60H  23/0000Z 19.9N  87.4W   60 KT  70 MPH
72H  23/1200Z 21.5N  88.9W   45 KT  50 MPH
96H  24/1200Z 25.0N  92.0W   50 KT  60 MPH
120H  25/1200Z 28.0N  94.0W   50 KT  60 MPH

$$
Forecaster Berg

t02436

命名Marco，明天擦過猶加敦半島。

000
WTNT44 KNHC 220254
TCDAT4

Tropical Storm Marco Discussion Number   7
NWS National Hurricane Center Miami FL       AL142020
1100 PM EDT Fri Aug 21 2020

An Air Force Reserve Hurricane Hunter aircraft has investigated the
system over the northwest Caribbean during the past few hours. The
plane reported a number of unflagged SFMR winds between 35 and 40 kt
and max flight level winds of 41 kt. A blend of these data supports
an intensity of 35 kt, and therefore, this system has been
designated as Tropical Storm Marco. Deep convection has increased
near and to the east of Marco's center during the past few hours.
Although there still isn't much evidence of inner-core banding, the
data from the plane does indicate that the center of Marco has
become better defined since the afternoon and that the minimum
pressure has dropped.

Unfortunately the intensity forecast has not become any clearer and
confidence in that aspect of the forecast is quite low. Marco is
embedded within an environment that could support a fast rate of
strengthening. However, recent microwave data does not indicate that
the system has developed an inner-core, and only gradual
strengthening is likely until it does. The intensity guidance spread
is quite high, with the GFS and ECMWF global models both showing
little further strengthening, while the HMON regional model rapidly
makes Marco a hurricane before it reaches the northeast tip of the
Yucatan peninsula. That possibility can not be ruled out, but a
majority of the intensity guidance favors the weaker solution of the
global models. Even with the HMON outlier included, the NHC
intensity forecast is above the model consensus. Once Marco moves
over the central Gulf of Mexico, a rapid increase in wind shear
associated with an upper-level trough should limit the potential for
further strengthening, and weakening is still anticipated before
Marco nears the northern Gulf Coast, as shown in the previous
official forecast.

Confidence in the track forecast is also lower than normal, as the
models spread remains quite high. Only small adjustments were made
to the NHC forecast which heavily favors the GFS and ECMWF solutions
on the left side of the track guidance. It is worth noting that the
NHC track forecast is near middle of the GFS and ECMWF ensembles.
Marco is currently forecast to move northwestward toward a weakness
in the subtropical ridge over the central Gulf of Mexico for the
next day or two, before the ridge builds and turns the tropical
cyclone farther west. Near the end of the period, Marco's track and
intensity could be also influenced by Tropical Storm Laura which is
also forecast to be over the Gulf of Mexico, however the details of
that interaction are highly uncertain at this time. Given the high
uncertainty in the forecast, larger than normal changes could be
required to future advisories.


Key Messages:

1. Marco is forecast to strengthen over the northwestern Caribbean
Sea through Saturday as it approaches the northeast coast of the
Yucatan Peninsula. A Hurricane Watch and a Tropical Storm Warning
are in effect for portions of that region.

2. The system is expected to move into the south-central Gulf of
Mexico as a tropical storm on Sunday. Although some strengthening
is anticipated on Sunday, weakening is forecast as the system
approaches the northwestern Gulf coast on Tuesday. It is still too
soon to know exactly the location and magnitude of impacts the
system will produce along the central or northwestern Gulf Coast,
and interests in that area should continue monitoring the progress
of this system over the next few days.


FORECAST POSITIONS AND MAX WINDS

INIT  22/0300Z 18.7N  84.9W   35 KT  40 MPH
12H  22/1200Z 19.7N  85.7W   45 KT  50 MPH
24H  23/0000Z 21.1N  86.7W   50 KT  60 MPH
36H  23/1200Z 22.7N  88.0W   55 KT  65 MPH
48H  24/0000Z 24.4N  89.5W   60 KT  70 MPH
60H  24/1200Z 25.9N  91.0W   60 KT  70 MPH
72H  25/0000Z 27.5N  92.8W   60 KT  70 MPH
96H  26/0000Z 29.0N  95.4W   45 KT  50 MPH...INLAND
120H  27/0000Z 30.0N  97.4W   30 KT  35 MPH...INLAND

$$
Forecaster Zelinsky

老農民版夜神月

03Z命名Marco，另外NHC於新報略微下修上望，暫不看好Marco能成為颶風

000
WTNT44 KNHC 220254
TCDAT4

Tropical Storm Marco Discussion Number   7
NWS National Hurricane Center Miami FL       AL142020
1100 PM EDT Fri Aug 21 2020

An Air Force Reserve Hurricane Hunter aircraft has investigated the
system over the northwest Caribbean during the past few hours. The
plane reported a number of unflagged SFMR winds between 35 and 40 kt
and max flight level winds of 41 kt. A blend of these data supports
an intensity of 35 kt, and therefore, this system has been
designated as Tropical Storm Marco. Deep convection has increased
near and to the east of Marco's center during the past few hours.
Although there still isn't much evidence of inner-core banding, the
data from the plane does indicate that the center of Marco has
become better defined since the afternoon and that the minimum
pressure has dropped.

Unfortunately the intensity forecast has not become any clearer and
confidence in that aspect of the forecast is quite low. Marco is
embedded within an environment that could support a fast rate of
strengthening. However, recent microwave data does not indicate that
the system has developed an inner-core, and only gradual
strengthening is likely until it does. The intensity guidance spread
is quite high, with the GFS and ECMWF global models both showing
little further strengthening, while the HMON regional model rapidly
makes Marco a hurricane before it reaches the northeast tip of the
Yucatan peninsula. That possibility can not be ruled out, but a
majority of the intensity guidance favors the weaker solution of the
global models. Even with the HMON outlier included, the NHC
intensity forecast is above the model consensus. Once Marco moves
over the central Gulf of Mexico, a rapid increase in wind shear
associated with an upper-level trough should limit the potential for
further strengthening, and weakening is still anticipated before
Marco nears the northern Gulf Coast, as shown in the previous
official forecast.

Confidence in the track forecast is also lower than normal, as the
models spread remains quite high. Only small adjustments were made
to the NHC forecast which heavily favors the GFS and ECMWF solutions
on the left side of the track guidance. It is worth noting that the
NHC track forecast is near middle of the GFS and ECMWF ensembles.
Marco is currently forecast to move northwestward toward a weakness
in the subtropical ridge over the central Gulf of Mexico for the
next day or two, before the ridge builds and turns the tropical
cyclone farther west. Near the end of the period, Marco's track and
intensity could be also influenced by Tropical Storm Laura which is
also forecast to be over the Gulf of Mexico, however the details of
that interaction are highly uncertain at this time. Given the high
uncertainty in the forecast, larger than normal changes could be
required to future advisories.


Key Messages:

1. Marco is forecast to strengthen over the northwestern Caribbean
Sea through Saturday as it approaches the northeast coast of the
Yucatan Peninsula. A Hurricane Watch and a Tropical Storm Warning
are in effect for portions of that region.

2. The system is expected to move into the south-central Gulf of
Mexico as a tropical storm on Sunday. Although some strengthening
is anticipated on Sunday, weakening is forecast as the system
approaches the northwestern Gulf coast on Tuesday. It is still too
soon to know exactly the location and magnitude of impacts the
system will produce along the central or northwestern Gulf Coast,
and interests in that area should continue monitoring the progress
of this system over the next few days.


FORECAST POSITIONS AND MAX WINDS

INIT  22/0300Z 18.7N  84.9W   35 KT  40 MPH
12H  22/1200Z 19.7N  85.7W   45 KT  50 MPH
24H  23/0000Z 21.1N  86.7W   50 KT  60 MPH
36H  23/1200Z 22.7N  88.0W   55 KT  65 MPH
48H  24/0000Z 24.4N  89.5W   60 KT  70 MPH
60H  24/1200Z 25.9N  91.0W   60 KT  70 MPH
72H  25/0000Z 27.5N  92.8W   60 KT  70 MPH
96H  26/0000Z 29.0N  95.4W   45 KT  50 MPH...INLAND
120H  27/0000Z 30.0N  97.4W   30 KT  35 MPH...INLAND

$$
Forecaster Zelinsky

老農民版夜神月

Marco過去24小時稍微東偏剛好閃過陸地,NHC上調上望至1級颶風75KT

000
WTNT44 KNHC 221454
TCDAT4

Tropical Storm Marco Discussion Number   9
NWS National Hurricane Center Miami FL       AL142020
1000 AM CDT Sat Aug 22 2020

Reconnaissance data, geostationary and microwave satellite imagery,
and radar data from Cuba all indicate that Marco is strengthening
quickly this morning.  The Air Force Reserve Hurricane Hunters
measured a peak 850-mb flight-level wind of 69 kt, and there were
several SFMR measurements of 50-55 kt to the northeast of the
center.  These data support raising Marco's initial intensity to 55
kt, and the central pressure based on dropsonde data has fallen to
992 mb.  The crew on the plane reported the formation of a partial
eyewall, which agrees with what we've seen on recent microwave and
radar images.

The track forecast has been complicated by the fact that the plane
has fixed Marco's center to the east of the previous forecast
track, and that makes the current motion north-northwestward, or
340/10 kt.  The subtropical ridge currently located over the
southwestern Atlantic is forecast to build westward along the
northern Gulf Coast during the next few days, and this expanding
ridge is expected to push Marco northwestward and then eventually
westward while the cyclone moves across the Gulf of Mexico.  This
general thinking has not changed, but the adjusted initial position
ended up shifting the track guidance to the north and east on this
cycle.  In response, the new NHC track forecast has been adjusted
eastward and northward during the first 3 days and is generally
between the HCCA and TVCN consensus aids.

Marco has finally tapped into the favorable conditions over the
northwestern Caribbean Sea, and the cyclone's overall small size and
small radius of maximum winds makes it susceptible to quick changes
in intensity. The tropical storm is just beginning to move into a
higher zone of shear to its north, but conditions should remain
conducive enough for Marco to intensity to a hurricane during the
next 24 hours. After that time, southwesterly shear is expected to
increase over 20 kt by day 2 and then over 30 kt by day 3, and those
conditions, along with the cyclone's small size, should cause
weakening as Marco gets closer to the central and northwestern Gulf
coast. The updated NHC intensity forecast has been increased during
the first 2 days and lies above the HCCA/Florida State
Superensemble solutions but below the SHIPS/LGEM scenarios. The
intensity forecast comes back in line with the previous forecast by
day 3 during the expected weakening phase, and Marco is ultimately
expected to dissipate over Texas by the end of the forecast period.

The updated track forecast suggests that watches could be required
for a portion of the central Gulf Coast later today.

Key Messages:

1. Marco is forecast to strengthen to a hurricane as it moves into
the southeastern Gulf of Mexico by tonight, and tropical storm
conditions are expected over the northeastern coast of the Yucatan
Peninsula and in extreme western Cuba.  Heavy rainfall is also
expected in the eastern portions of the Mexican states of Quintana
Roo and Yucatan, and across far western Cuba, which could result in
flash flooding.

2. Marco is expected to move across the central Gulf of Mexico as a
hurricane Sunday and approach the central Gulf Coast on Monday.
There is an increasing risk of impacts from storm surge, winds, and
heavy rainfall from the upper Texas coast to Louisiana early next
week, and interests there should monitor the progress of Marco, as
storm surge, tropical storm, and/or hurricane watches could be
issued later today.


FORECAST POSITIONS AND MAX WINDS

INIT  22/1500Z 20.9N  85.3W   55 KT  65 MPH
12H  23/0000Z 22.1N  86.0W   65 KT  75 MPH
24H  23/1200Z 23.9N  87.1W   75 KT  85 MPH
36H  24/0000Z 25.6N  88.4W   75 KT  85 MPH
48H  24/1200Z 27.2N  89.9W   70 KT  80 MPH
60H  25/0000Z 28.5N  91.6W   60 KT  70 MPH
72H  25/1200Z 29.1N  93.6W   50 KT  60 MPH
96H  26/1200Z 29.3N  96.6W   35 KT  40 MPH...INLAND
120H  27/1200Z...DISSIPATED

$$
Forecaster Berg

老農民版夜神月

NHC特報升格Marco為颶風
並預測Marco將於約+36H後進逼路易斯安那州

000
WTNT64 KNHC 231629
TCUAT4

Hurricane Marco Tropical Cyclone Update
NWS National Hurricane Center Miami FL       AL142020
1130 AM CDT Sun Aug 23 2020

...MARCO BECOMES A HURRICANE...
...LIFE-THREATENING STORM SURGE AND HURRICANE-FORCE WINDS EXPECTED
ALONG PORTIONS OF THE U.S. GULF COAST...

Data from an Air Force Reserve Hurricane Hunter aircraft indicate
that Marco has strengthened into a hurricane with maximum winds of
75 mph (120 km/h) with higher gusts.


SUMMARY OF 1130 AM CDT...1630 UTC...INFORMATION
----------------------------------------------
LOCATION...25.0N 87.4W
ABOUT 300 MI...480 KM SSE OF THE MOUTH OF THE MISSISSIPPI RIVER
ABOUT 460 MI...740 KM SE OF LAFAYETTE LOUISIANA
MAXIMUM SUSTAINED WINDS...75 MPH...120 KM/H
PRESENT MOVEMENT...NNW OR 340 DEGREES AT 14 MPH...22 KM/H
MINIMUM CENTRAL PRESSURE...992 MB...29.29 INCHES

$$
Forecaster Latto

老農民版夜神月

Marco於昨(24日)凌晨巔峰並短暫達標C1後便開始逐步減弱
NHC15Z新報定強45KT,將於今日上午登陸路易斯安那州

000
WTNT44 KNHC 241445
TCDAT4

Tropical Storm Marco Discussion Number  17
NWS National Hurricane Center Miami FL       AL142020
1000 AM CDT Mon Aug 24 2020

Strong southwesterly shear is taking its toll on Marco, with the
edge of the nearest deep convection now displaced 50 n mi northeast
of the exposed circulation center. Data from an Air Force Reserve
Hurricane Hunter aircraft that investigated the system this morning
measured 45-kt surface winds with the onboard SFMR instrument in
that convection, but winds of only 20 to 30 kt were measured
between this thunderstorm activity and the cyclone's center.
Sampling by the aircraft has also revealed that winds of tropical
storm force are likely no longer occurring in any portion of the
circulation except in that convection. Based on the SFMR data, the
initial intensity is initialized at 45 kt.

The shear is not forecast to abate in the foreseeable future, and
the simulated satellite imagery in the GFS and ECMWF suggests that
Marco will degenerate into a remnant low on Tuesday. The latest NHC
forecast is near the various consensus aids, which shows the cyclone
weakening to a tropical depression late tonight. Based on the
updated intensity forecast, tropical storm conditions are no longer
expected to be produced by Marco over the central portions of the
Louisiana coast, and the Tropical Storm Warnings for those
locations have been discontinued.

Marco has slowed down and has moved a little to the right of the
forecast track over the past few hours, with an initial motion of
NNW/7 kt. The track guidance for the entire forecast period has
shifted back northward, and is just south of where it was this time
yesterday. The official forecast track was adjusted eastward in the
near term to accommodate the recent right-of-track bias. After 12
h, the track forecast lies between the previous one and most of the
consensus track guidance. On this track, Marco is expected to move
inland tonight, and remain inland when the system turns
west-northwestward in the low-level flow by Tuesday morning.


Key Messages:

1. Gusty winds, dangerous storm surge, and heavy rainfall are
expected from Marco along portions of the Gulf Coast beginning
later today. Interests in these areas should follow any advice given
by local government officials.

2. Tropical Storm Laura could bring additional storm surge,
rainfall, and wind impacts to portions of the U.S. Gulf Coast by the
middle of the week. This could result in a prolonged period of
hazardous weather for areas that may also be affected by Marco.
Interests there should monitor the progress of Marco and Laura and
updates to the forecast during the next few days.


FORECAST POSITIONS AND MAX WINDS

INIT  24/1500Z 28.5N  88.5W   45 KT  50 MPH
12H  25/0000Z 29.2N  89.3W   35 KT  40 MPH...INLAND
24H  25/1200Z 30.0N  91.3W   30 KT  35 MPH...POST-TROP/REMNT LOW
36H  26/0000Z 30.5N  93.6W   30 KT  35 MPH...POST-TROP/REMNT LOW
48H  26/1200Z 30.9N  95.9W   25 KT  30 MPH...POST-TROP/REMNT LOW
60H  27/0000Z...DISSIPATED

$$
Forecaster Latto

t02436

23Z判定登陸

ZCZC MIATCUAT4 ALL
TTAA00 KNHC DDHHMM

Tropical Storm Marco Tropical Cyclone Update
NWS National Hurricane Center Miami FL       AL142020
600 PM CDT Mon Aug 24 2020

...MARCO MAKES LANDFALL NEAR THE MOUTH OF THE MISSISSIPPI...
...EXPECTED TO BECOME A TROPICAL DEPRESSION LATER TONIGHT...

Visible satellite imagery and surface observations indicate that
Marco made landfall near the mouth of the Mississippi River around
600 PM CDT. Data from an Air Force Reserve Hurricane Hunter Aircraft
indicate that Marco is producing a small area of
tropical-storm-force winds over water to the northeast of the
center. These winds will likely subside during the next few hours as
Marco moves along the coast of Louisiana. Heavy rain will continue
along portions of the north-central Gulf Coast through tonight.

The estimated minimum pressure at the time of landfall was 1006 mb
(29.71 inches).


SUMMARY OF 600 PM CDT...2300 UTC...INFORMATION
----------------------------------------------
LOCATION...29.0N 89.2W
ABOUT 0 MI...0 KM N OF THE MOUTH OF THE MISSISSIPPI RIVER
MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H
PRESENT MOVEMENT...WNW OR 290 DEGREES AT 8 MPH...13 KM/H
MINIMUM CENTRAL PRESSURE...1006 MB...29.71 INCHES

$$
Forecaster Zelinsky

NNNN

03Z已減弱為TD

000
WTNT44 KNHC 250231
TCDAT4

Tropical Depression Marco Discussion Number  20
NWS National Hurricane Center Miami FL       AL142020
1000 PM CDT Mon Aug 24 2020

Visible imagery and surface observations indicated that Marco made
landfall around 6 pm CDT near the mouth of the Mississippi River.
Shortly before landfall, reports from an Air Force Reserve Hurricane
Hunter plane indicated that Marco was still producing a small area
of tropical-storm-force winds over water to the northeast of its
center. Since then, the system has moved almost due west along the
southeast coast of Louisiana while its deep convection has become
farther displaced from the low-level center. Between the lack of
central convection and Marco's proximity to land, it is likely that
the winds have decreased since earlier this evening and the
intensity has been lowered to 30 kt.

If deep convection does not redevelop overnight, Marco will become a
remnant low as soon as Tuesday morning. Regardless of its status,
Marco should move generally westward near the coast of Louisiana
while it weakens for the next day or so and could continue to
produce heavy rain for portions of the north-central Gulf Coast
tonight. The system is then forecast to dissipate by early
Wednesday, if not sooner.


FORECAST POSITIONS AND MAX WINDS

INIT  25/0300Z 29.0N  89.8W   30 KT  35 MPH
12H  25/1200Z 29.0N  91.3W   25 KT  30 MPH...POST-TROP/REMNT LOW
24H  26/0000Z 29.0N  93.3W   25 KT  30 MPH...POST-TROP/REMNT LOW
36H  26/1200Z...DISSIPATED

$$
Forecaster Zelinsky