老農民版夜神月

NHC升格C1

000
WTPZ42 KNHC 121450
TCDEP2

Hurricane Linda Discussion Number  10
NWS National Hurricane Center Miami FL       EP122021
900 AM MDT Thu Aug 12 2021

Linda has been trying to form an eye in conventional satellite
imagery during the past few hours, but that feature has been
obscured by the development of new convective bursts near the
center.  An AMSR2 microwave pass from 0850 UTC indicated that the
structure remains well organized, if not a little tilted with
height due to shear, and a ragged mid-level eye feature was noted.  
Objective intensity estimates are at hurricane strength--T4.4/75 kt
from the UW-CIMSS ADT and 66 kt from SATCON--but subjective CI
numbers from TAFB and SAB remain at 3.5/55 kt.  Given the continued
attempts at eye formation, I have elected to lean on the side of the
objective numbers and increase the initial intensity to 65 kt,
making Linda a hurricane.

The AMSR2 pass revealed that Linda has been moving a little to the
right of the previous forecast track, and the initial motion is
estimated to be west-northwestward, or 300/7 kt.  Mid-tropospheric
ridging located over northern Mexico should keep Linda on a
west-northwestward track for the next 2 to 3 days.  After that
time, another ridge is forecast to slide westward from California
out over the Pacific, which should have a blocking influence on
Linda and cause it to turn back toward the west.  In fact, by day 5,
most of the track models are showing a south-of-due-west motion.
On the whole, the guidance is showing a normal amount of spread, and
the NHC track forecast has only been shifted slightly eastward and
northward through day 3 to account for the adjustment of the initial
position.  This solution is very close to the HCCA and TVCE
consensus aids.

Moderate northerly to north-northeasterly shear continues to affect
the cyclone, and the effect of this shear was seen in the slight
offset of the low- and mid-level centers in microwave imagery.  The
shear is forecast to subside slightly during the next couple of
days while the hurricane moves over warm waters of 28-29 degrees
Celsius and within an environment of upper-level divergence.  The
limiting effects of the shear are likely to support gradual
strengthening during the next couple of days, and the NHC intensity
forecast is within the relatively tightly packed guidance suite
during that time.  During the 3-5 day period, shear is expected to
decrease substantially, but less conducive thermodynamic conditions
should cause Linda to gradually lose intensity, potentially
weakening to a tropical storm by day 5.

FORECAST POSITIONS AND MAX WINDS

INIT  12/1500Z 14.8N 107.7W   65 KT  75 MPH
12H  13/0000Z 15.6N 109.1W   65 KT  75 MPH
24H  13/1200Z 16.6N 111.2W   70 KT  80 MPH
36H  14/0000Z 17.7N 113.4W   75 KT  85 MPH
48H  14/1200Z 18.6N 115.5W   80 KT  90 MPH
60H  15/0000Z 19.2N 117.6W   80 KT  90 MPH
72H  15/1200Z 19.4N 119.6W   75 KT  85 MPH
96H  16/1200Z 19.1N 123.4W   65 KT  75 MPH
120H  17/1200Z 19.0N 127.2W   55 KT  65 MPH

$$
Forecaster Berg

t02436

底層風眼建立完成，15Z提升評價至90節，坐C2望C3。

000
WTPZ42 KNHC 131444
TCDEP2

Hurricane Linda Discussion Number  14
NWS National Hurricane Center Miami FL       EP122021
900 AM MDT Fri Aug 13 2021

Linda's structure has continued to improve since early this morning.
An eye was evident in longwave and shortwave IR imagery from GOES-17
and GOES-15 near 1200 UTC, though it has since become obscured by
cold cloud tops associated with eyewall convection. An earlier AMSR
overpass showed evidence of a ring of shallow to moderate
convection, often associated with rapidly intensifying cyclones.
Intensity estimates at 1200 UTC ranged from 77 kt to 97 kt, so the
initial intensity was set at 90 kt, in closest agreement with the
U-W CIMSS SATCON. It is worth noting that Linda's intensity is in a
range where estimates can range greatly, so confidence in that
assessment is not particularly high.

Computational problems with the GFS this morning has limited the
guidance available for the forecast, particularly with respect to
the intensity. Therefore, despite the higher initial intensity and
recent improvement in convective structure, the official intensity
forecast was only modestly increased in the short term. It does not
appear that wind shear will be a major inhibiting factor during the
next day or two. Environmental moisture and SSTs should also be
sufficient for further strengthening. The NHC forecast is a little
above the model consensus and previous forecast for the next
24-36 h. After that time, Linda should move over cooler SSTs which
should cause at least gradual weakening. By the end of the 5-day
period, the NHC forecast is in line with the consensus and identical
to the previous advisory.

Only small tweaks were made to the NHC track forecast. Linda
continues to move toward the west-northwest with an estimated
forward speed of 11 kt. The global models unanimously forecast that
a deep-layer ridge to the north of Linda will build over the
weekend, causing the hurricane to turn westward, and then
west-southwestward by early next week. Confidence in the track
forecast is quite high due to the agreement among the track models.

FORECAST POSITIONS AND MAX WINDS

INIT  13/1500Z 16.9N 111.8W   90 KT 105 MPH
12H  14/0000Z 17.6N 113.6W  100 KT 115 MPH
24H  14/1200Z 18.4N 115.9W  105 KT 120 MPH
36H  15/0000Z 18.8N 118.2W  105 KT 120 MPH
48H  15/1200Z 18.8N 120.3W  100 KT 115 MPH
60H  16/0000Z 18.6N 122.3W   90 KT 105 MPH
72H  16/1200Z 18.2N 124.2W   80 KT  90 MPH
96H  17/1200Z 17.5N 128.0W   65 KT  75 MPH
120H  18/1200Z 18.5N 132.0W   60 KT  70 MPH

$$
Forecaster Zelinsky

老農民版夜神月

NHC升格MH,為今年東太第二個MH

000
WTPZ42 KNHC 132046
TCDEP2

Hurricane Linda Discussion Number  15
NWS National Hurricane Center Miami FL       EP122021
300 PM MDT Fri Aug 13 2021

Linda has become an impressive looking hurricane this afternoon. The
eye that first became evident on geostationary satellite imagery
this morning has continued to clear out and warm while the
surrounding cold convection associated with the eyewall wraps around
the eye. The convective structure on microwave imagery has also
improved, with a distinct eye and closed eyewall apparent in an
earlier 1417 UTC SSMIS pass. The 1800 UTC subjective and objective
Dvorak estimates were in unanimous agreement with T5.5/102 kt
provided by SAB, TAFB, and ADT sources. Therefore, the initial
intensity has been increased to 100 kt this advisory, making Linda a
major hurricane.

Linda continues to move steadily to the west-northwest, at 300/12
kt. The track philosophy has not changed much over the past 24
hours. A mid- to upper-level ridge currently centered over the
southwestern United States is expected to expand westward, building
in to the northwest of the hurricane. This evolution should result
in Lisa's motion bending left, first to the west, and then to the
west-southwest over the next 2-3 days. The track guidance remains
tightly clustered near and just slightly poleward of the previous
forecast track. The latest NHC track forecast was nudged just
slightly northward over the first few days, but is nearly on top of
the previous forecast by the end of the period.

Linda has rapidly intensified, with a 35-kt increase over the past
24 hours, and the hurricane still has an opportunity to intensify a
bit more over the next 12 hours. After 24 hours, Linda will begin to
cross over gradually decreasing sea-surface temperatures and into a
and drier mid-level environment. These factors should lead to
gradual weakening. One fly in the ointment is that the shear
diagnosed by SHIPS guidance is expected to remain low and easterly
while sea-surface temperatures remain between 26-27 C through 60
hours. Both the ECMWF and HWRF simulated brightness temperatures
during that time suggest that Linda could develop a stable annular
structure, which often results in a slower than expected weakening
rate. For this reason, the latest intensity forecast only shows
gradual weakening through 60 hours, which is a bit above the HCCA
consensus aid. More rapid weakening is likely at the end of the
forecast period when Linda will move over sub 25 C water.


FORECAST POSITIONS AND MAX WINDS

INIT  13/2100Z 17.5N 112.9W  100 KT 115 MPH
12H  14/0600Z 18.2N 114.6W  110 KT 125 MPH
24H  14/1800Z 18.9N 116.9W  105 KT 120 MPH
36H  15/0600Z 19.2N 119.2W  100 KT 115 MPH
48H  15/1800Z 19.1N 121.3W   95 KT 110 MPH
60H  16/0600Z 18.7N 123.3W   85 KT 100 MPH
72H  16/1800Z 18.2N 125.2W   75 KT  85 MPH
96H  17/1800Z 17.9N 129.0W   65 KT  75 MPH
120H  18/1800Z 19.0N 133.0W   55 KT  65 MPH

$$
Forecaster Papin/Brennan

老農民版夜神月

NHC升格C4

WTPZ42 KNHC 141434
TCDEP2

Hurricane Linda Discussion Number  18
NWS National Hurricane Center Miami FL       EP122021
800 AM PDT Sat Aug 14 2021

Linda is maintaining a well-defined 15-n mi wide eye, and a quite
symmetric surrounding convective cloud pattern.  Taking a blend of
the latest subjective and objective Dvorak estimates gives a current
intensity estimate of about 115 kt, i.e. category 4 strength.

Linda may undergo an eyewall replacement later today, which is
typical for intense hurricanes, and this could cause some
short-term fluctuations in intensity.  The hurricane is currently
in a low-vertical shear environment, and the dynamical guidance
indicates that the shear will remain low for the next few days.
However, SSTs beneath Linda should gradually lower along with
decreasing environmental mid-level humidities during the next
several days. Thus a slow weakening trend should commence by
tonight.  The official intensity forecast is a blend of the
corrected and simple model consensus predictions.

The initial motion is estimated to be west-northwestward, or
290/11 kt.  There is little change to the expected steering
scenario.  Linda is moving along the southern side of a pronounced
subtropical ridge.  The ridge is predicted by the global models to
build westward to the northwest of the hurricane during the next
couple of days.  This should cause Linda to turn toward the
west-southwest within the next day or two.  Late in the forecast
period, as the ridge weakens, the cyclone is forecast to turn
westward. The NHC track forecast is very close to the previous
one and in good agreement with the latest dynamical model consensus.

FORECAST POSITIONS AND MAX WINDS

INIT  14/1500Z 18.8N 116.1W  115 KT 130 MPH
12H  15/0000Z 19.1N 117.7W  110 KT 125 MPH
24H  15/1200Z 19.2N 119.8W   95 KT 110 MPH
36H  16/0000Z 19.0N 121.8W   85 KT 100 MPH
48H  16/1200Z 18.5N 123.8W   80 KT  90 MPH
60H  17/0000Z 18.0N 125.6W   75 KT  85 MPH
72H  17/1200Z 17.9N 127.5W   70 KT  80 MPH
96H  18/1200Z 18.5N 131.5W   65 KT  75 MPH
120H  19/1200Z 20.5N 136.0W   55 KT  65 MPH

$$
Forecaster Pasch

老農民版夜神月

NHC降格C2,將持續減弱

000
WTPZ42 KNHC 152032
TCDEP2

Hurricane Linda Discussion Number  23
NWS National Hurricane Center Miami FL       EP122021
1100 AM HST Sun Aug 15 2021

Linda now has the classic truck tire or doughnut appearance of an
annular hurricane in infrared satellite imagery.  The large eye is
about 35 n mi in diameter, and the surrounding cold cloud tops are
uniformly 70-90 n mi thick in all quadrants.  The initial intensity
is lowered slightly to 95 kt based on Dvorak estimates of T5.0/90 kt
from TAFB and T5.5/102 kt from SAB, and this value also matches the
latest objective ADT and SATCON estimates.

Linda has almost turned toward the west-southwest with an initial
motion of 260/10 kt, a result of a strong mid-level high centered
over California and Nevada.  This feature should push Linda toward
the west-southwest during the next 24 hours, but a repositioning of
the high over the North Pacific in a few days will allow the
hurricane to turn back toward the west by 36 hours and then the
west-northwest by day 3.  The track models remain in good agreement
on this scenario.  The NHC track forecast lies near the southern
edge of the guidance envelope, leaning towards the HCCA consensus
aid, and it essentially lies right on top of the previous official
forecast.

With little to no shear expected during the next 5 days, Linda's
intensity will be driven by thermodynamic factors.  The hurricane's
west-southwestward motion has it paralleling the sea surface
temperature gradient, keeping it over waters around 26 degrees
Celsius for the next 3 days or so.  Since annular hurricanes
typically weaken only gradually with these types of environmental
conditions, the NHC intensity forecast is above the various
intensity consensus aids and leans toward the SHIPS model, which is
at the upper end of the guidance envelope.  Linda is likely to
weaken below hurricane intensity after day 3 once it moves over
much colder waters.  Although not explicitly shown here, it is
possible that Linda could lose organized deep convection and become
a post-tropical gale by day 5.


FORECAST POSITIONS AND MAX WINDS

INIT  15/2100Z 18.8N 121.2W   95 KT 110 MPH
12H  16/0600Z 18.4N 122.5W   90 KT 105 MPH
24H  16/1800Z 17.8N 124.3W   85 KT 100 MPH
36H  17/0600Z 17.6N 126.0W   80 KT  90 MPH
48H  17/1800Z 17.7N 127.7W   75 KT  85 MPH
60H  18/0600Z 18.1N 129.7W   70 KT  80 MPH
72H  18/1800Z 18.9N 132.0W   65 KT  75 MPH
96H  19/1800Z 20.7N 136.7W   55 KT  65 MPH
120H  20/1800Z 22.5N 140.9W   40 KT  45 MPH

$$
Forecaster Berg

老農民版夜神月

NHC新報將定強降至85KT,並預測其將亡於踏入CPHC轄區那一刻

FORECAST POSITIONS AND MAX WINDS

INIT  16/2100Z 17.7N 124.6W   85 KT 100 MPH
12H  17/0600Z 17.6N 125.9W   85 KT 100 MPH
24H  17/1800Z 17.7N 127.7W   85 KT 100 MPH
36H  18/0600Z 18.2N 129.8W   85 KT 100 MPH
48H  18/1800Z 19.0N 132.2W   75 KT  85 MPH
60H  19/0600Z 19.9N 134.8W   60 KT  70 MPH
72H  19/1800Z 20.7N 137.5W   50 KT  60 MPH
96H  20/1800Z 22.0N 142.6W   40 KT  45 MPH...POST-TROPICAL
120H  21/1800Z 23.0N 146.8W   35 KT  40 MPH...POST-TROPICAL

老農民版夜神月

持續減弱至C1,80KT
NHC新報看好其能成為本年度第一個進入CPHC轄區仍未成為殘餘低氣壓的TC
雖然還是要看CPHC想不想負責就是了XDD

老農民版夜神月

對流有所增強,重回C2(90KT)

000
WTPZ42 KNHC 180255
TCDEP2

Hurricane Linda Discussion Number  32
NWS National Hurricane Center Miami FL       EP122021
500 PM HST Tue Aug 17 2021

Linda has made a bit of a comeback over the last 6-12 hours. While
the eye continues to remain clear and warm, the eyewall convection
has been gradually cooling over the course of the day, with a
thickening ring of -60 to -65 C cloud top temperatures occasionally
surrounding the eye. This has led to an increase in the most recent
subjective Dvorak intensity estimates which at 0000 UTC were
T5.5/102 kt from SAB and T5.0/90 kt from TAFB. The latest objective
UW-CIMSS ADT estimate is up to T5.3/97 kt though the most recent
SATCON estimate was only 79 kt. Taking a blend of these data yields
an estimated intensity of 90 kt for this advisory.

Linda is starting to gain some latitude, with the estimated motion
now at 280/10 kt. The track guidance philosophy remains the same,
with a mid-level ridge well-established across the North Pacific
expected to keep Linda moving on a west-northwestward track thorough
the forecast period. Once again, the guidance has shifted a bit
faster over the forecast period, and the latest NHC track forecast
has also been nudged a little faster. Based on the latest forecast,
Linda should be crossing into the Central Pacific in about 48 hours,
and is expected to pass by to the north of the Hawaiian Islands as a
post-tropical gale late in the weekend.

Linda's recent increase in intensity could be related to the cyclone
moving over a small finger of warmer sea-surface temperatures (SSTs)
currently. The storm has continued to maintain its stable annular
structure, and little change in strength is expected during the next
12 h. However, SSTs will soon begin to decrease once again and
should drop below 25 C beyond 24 hours. While the deep-layer
vertical wind shear diagnosed by SHIPS is expected to remain low for
the next 72 hours, a bit more westerly mid-level shear could begin
to undercut the outflow layer in 24-36 hours. For these reasons,
Linda should begin a more pronounced weakening trend after 24 hours,
with the tropical cyclone forecast to finally drop below hurricane
intensity Thursday Night. The latest NHC intensity forecast remains
on the high side of the guidance for the first 24 hours, but then is
brought down to the guidance mean afterwards, in best agreement with
the HFIP Corrected Consensus Approach (HCCA) guidance. While SSTs do
begin to increase again after 72 hours, an increase in southwesterly
shear is expected to prevent organized convection from redeveloping
near the center, and Linda is forecast to become a post-tropical
gale by that time.


FORECAST POSITIONS AND MAX WINDS

INIT  18/0300Z 17.9N 129.5W   90 KT 105 MPH
12H  18/1200Z 18.4N 131.2W   90 KT 105 MPH
24H  19/0000Z 19.2N 133.9W   80 KT  90 MPH
36H  19/1200Z 20.0N 136.9W   70 KT  80 MPH
48H  20/0000Z 20.7N 140.0W   60 KT  70 MPH
60H  20/1200Z 21.3N 142.9W   50 KT  60 MPH
72H  21/0000Z 21.6N 145.6W   40 KT  45 MPH...POST-TROPICAL
96H  22/0000Z 22.2N 150.0W   35 KT  40 MPH...POST-TROPICAL
120H  23/0000Z 22.7N 154.2W   35 KT  40 MPH...POST-TROPICAL

$$
Forecaster Papin/Brown