EPAC: KAY - Post-Tropical

[NotoSans]

ASCAT has a low bias and it's very likely that the maximum winds are not caught. This problem is much more evident when it comes to small tropical cyclones.

18Z best track up to 45 kt.
EP, 12, 2016082118, , BEST, 0, 213N, 1150W, 45, 1000, TS, 34, NEQ, 30, 30, 30, 40, 1009, 175, 20, 55, 0, E, 0, , 0, 0, KAY, M, 12, NEQ, 60, 60, 60, 60, genesis-num, 021,

[cycloneye]

TROPICAL STORM KAY DISCUSSION NUMBER 13
NWS NATIONAL HURRICANE CENTER MIAMI FL EP122016
200 PM PDT SUN AUG 21 2016

Kay's cloud pattern has become better organized since its overnight
convective burst. A small and quasi-circular central dense overcast
has formed, with the low-level center located nearly in the middle
of this convective mass. An earlier SSMI/S pass also showed the
presence of a mid-level convective ring, indicative of an increase
in the system's organization. A 1658 ASCAT pass indicated wind
speeds around 45 kt, and the initial intensity estimate is set to
this value.

Today's intensification episode has likely ended. However, with the
cyclone still over relatively waters and in a reasonably moist and
light-shear environment, Kay should maintain its strength for the
next 12 hours or so. By 24 hours, the storm should reach
significantly cooler waters, and encounter considerably less
conducive atmospheric thermodynamic conditions. Weakening should
commence by that time, with a rapid decay likely in 24 to 48 hours.
Remnant low status is still indicated in 2 days, with dissipation
likely in 3 days in agreement with global models. The NHC intensity
forecast is largely the same as the previous one, except in the very
short term where it is a bit higher due to the cyclone's recent
intensification.

Kay continues moving slowly west-northwestward, with the latest
initial motion estimate of 300/07. Kay is being steered on this
course by the flow around the southwestern edge of a mid-level
anticyclone extending westward from northern Mexico. A turn toward
the west with some increase in forward speed is expected once the
cyclone becomes a shallow vortex to the south of a building
low-level ridge. No significant changes have been made to the
forecast track this cycle, with the forecast track close to a blend
of the ECMWF and GFS model solutions.

FORECAST POSITIONS AND MAX WINDS

INIT 21/2100Z 21.5N 115.3W 45 KT 50 MPH
12H 22/0600Z 21.9N 116.2W 45 KT 50 MPH
24H 22/1800Z 22.3N 117.3W 40 KT 45 MPH
36H 23/0600Z 22.8N 118.8W 35 KT 40 MPH
48H 23/1800Z 23.1N 120.4W 30 KT 35 MPH...POST-TROP/REMNT LOW
72H 24/1800Z...DISSIPATED

$$
Forecaster Kimberlain

[Kingarabian]

They go with ASCATS low bias 45kts despite 55kts from SAB and 60kts from ADT.

50kts would've been more reasonable.

[Kingarabian]

Still intensifying.

[Kingarabian]

Looks like GEOS is down or SSD is having problems for the EPAC. No satellite imagery for Kay and I think SAB numbers will be delayed.

Back online now.

[cycloneye]

TROPICAL STORM KAY DISCUSSION NUMBER 14
NWS NATIONAL HURRICANE CENTER MIAMI FL EP122016
800 PM PDT SUN AUG 21 2016

Kay's cloud pattern has shown little change in organization since
earlier today. The storm continues to produce very cold-topped
deep convection over a small area near the center. The upper-level
outflow remains fairly symmetric, which is consistent with the
low-shear environment. The current intensity estimate is kept at
45 kt in agreement with a Dvorak estimate from TAFB. Kay is
currently over marginally warm SSTs, but should be moving over
progressively cooler waters during the next day or two. This,
along with an increasingly less humid mid-level air mass, should
cause weakening. The official intensity forecast is very close
to the latest intensity guidance consensus, IVCN.

The storm continues to move west-northwestward, or around 300/6 kt.
There are no significant changes to the track forecast or forecast
reasoning. Kay should continue to move along the southwestern
periphery of a mid-level ridge for the next day or so. By Tuesday,
when the system should become a shallow cyclone, a turn toward the
west following the low-level flow is anticipated. The official
track forecast is roughly in the middle of the dynamical guidance
envelope.

FORECAST POSITIONS AND MAX WINDS

INIT 22/0300Z 21.8N 115.9W 45 KT 50 MPH
12H 22/1200Z 22.1N 116.7W 45 KT 50 MPH
24H 23/0000Z 22.4N 118.0W 40 KT 45 MPH
36H 23/1200Z 22.7N 119.2W 35 KT 40 MPH
48H 24/0000Z 23.0N 120.8W 30 KT 35 MPH...POST-TROP/REMNT LOW
72H 25/0000Z...DISSIPATED

$$
Forecaster Pasch

[cycloneye]

TROPICAL STORM KAY DISCUSSION NUMBER 15
NWS NATIONAL HURRICANE CENTER MIAMI FL EP122016
200 AM PDT MON AUG 22 2016

Deep convection associated with Kay has decreased a little in both
intensity and coverage during the last several hours, but the
cyclone is maintaining a small central dense overcast feature. The
Dvorak CI-numbers from TAFB and SAB are still 3.0/45 kt, and the
initial wind speed is held at that value for this advisory. Kay is
nearing the 26-deg-C isotherm, and it will likely cross into those
cooler waters later today. These unfavorable oceanic conditions
combined with a drier air mass along the expected track should cause
a slow decay during the next couple of days. Kay will likely
degenerate into a remnant low pressure area when it moves over water
temperatures below 25 deg C in 36 to 48 hours. All of the global
models show the system opening into a trough by Wednesday night, and
the official forecast follows that guidance.

Kay continues to move west-northwestward to northwestward at about
7 kt as it is being steered by a subtropical ridge to its northeast.
A gradual turn to the left is expected during the next couple of
days as Kay becomes shallower and is steered by the low-level trade
wind flow. The NHC track forecast is similar to the previous one
and lies fairly close to the various consensus aids.

FORECAST POSITIONS AND MAX WINDS

INIT 22/0900Z 22.2N 116.6W 45 KT 50 MPH
12H 22/1800Z 22.5N 117.6W 40 KT 45 MPH
24H 23/0600Z 22.8N 118.8W 35 KT 40 MPH
36H 23/1800Z 23.2N 120.3W 30 KT 35 MPH
48H 24/0600Z 23.5N 121.8W 30 KT 35 MPH...POST-TROP/REMNT LOW
72H 25/0600Z...DISSIPATED

$$
Forecaster Cangialosi

[cycloneye]

TROPICAL STORM KAY DISCUSSION NUMBER 16
NWS NATIONAL HURRICANE CENTER MIAMI FL EP122016
800 AM PDT MON AUG 22 2016

Microwave data and first-light visible imagery indicate that the
convection associated with Kay has become less organized, with the
low-level center now lying near the southeast edge of the
convective area. The initial intensity is decreased to 40 kt based
mainly on a blend of subjective satellite intensity estimates from
TAFB and SAB combined with the observed decay of the cloud pattern.

The microwave data show that Kay turned westward during the night
with the initial motion now 280/6. A low- to mid-level ridge to
the north of the cyclone should steer it generally westward to
west-northwestward until dissipation. The new forecast track,
which lies near the model consensus, is shifted somewhat to the
south of the previous track due to the current position and motion.

Kay will be moving over decreasing sea surface temperatures, which
should cause a continued gradual weakening. The new intensity
forecast calls for the cyclone to become a depression in 24 hours
or less, and for it to subsequently decay to a remnant low by 36
hours. The forecast also follows the global models in showing the
system weakening to a trough after 72 hours.


FORECAST POSITIONS AND MAX WINDS

INIT 22/1500Z 22.0N 117.1W 40 KT 45 MPH
12H 23/0000Z 22.2N 118.1W 35 KT 40 MPH
24H 23/1200Z 22.5N 119.4W 30 KT 35 MPH
36H 24/0000Z 22.9N 121.0W 25 KT 30 MPH...POST-TROP/REMNT LOW
48H 24/1200Z 23.2N 122.6W 20 KT 25 MPH...POST-TROP/REMNT LOW
72H 25/1200Z...DISSIPATED

$$
Forecaster Beven

[cycloneye]

TROPICAL STORM KAY DISCUSSION NUMBER 17
NWS NATIONAL HURRICANE CENTER MIAMI FL EP122016
200 PM PDT MON AUG 22 2016

The convective structure of Kay has continued to degenerate during
the day, with the deep convection now confined to the northwestern
quadrant. The initial intensity is decreased to 35 kt based mainly
on a blend of subjective satellite intensity estimates from TAFB and
SAB combined with the observed decay of the cloud pattern.

The initial motion is now 275/7. A low- to mid-level ridge to
the north of the cyclone should steer it generally westward to
west-northwestward until dissipation. The new track guidance
envelope has shifted a little northward, and the new forecast track
lies a little to the south of the consensus models.

Kay should continue to gradually weaken as it moves over decreasing
sea surface temperatures. The intensity forecast continues to call
for the cyclone to become a depression in 24 hours or less, and for
it to subsequently decay to a remnant low by 36 hours. The forecast
also follows the global models in showing the system weakening to a
trough by 72 hours.


FORECAST POSITIONS AND MAX WINDS

INIT 22/2100Z 22.0N 118.0W 35 KT 40 MPH
12H 23/0600Z 22.1N 119.1W 35 KT 40 MPH
24H 23/1800Z 22.5N 120.6W 30 KT 35 MPH
36H 24/0600Z 22.8N 122.1W 25 KT 30 MPH...POST-TROP/REMNT LOW
48H 24/1800Z 22.9N 123.6W 20 KT 25 MPH...POST-TROP/REMNT LOW
72H 25/1800Z...DISSIPATED

$$
Forecaster Beven

[cycloneye]

TROPICAL STORM KAY DISCUSSION NUMBER 18
NWS NATIONAL HURRICANE CENTER MIAMI FL EP122016
800 PM PDT MON AUG 22 2016

Most of the deep convection associated with Kay has dissipated,
likely due to the continued entrainment of stable air and marginal
SSTs. However, visible satellite images showed a well-defined
low cloud circulation with tightly curved bands. The current
intensity is kept at 35 kt following a Dvorak estimate from TAFB.
Kay is crossing the 25.5 deg C SST isotherm and will continue to
move into a stable and increasingly dry air mass. These unfavorable
factors should lead to weakening, and Kay is likely to degenerate
into a remnant low in 36 hours. Unless deep convection makes a
comeback, however, this event may occur sooner than that.

The motion remains about the same, or 270/7 kt. There is basically
no change to the track forecast reasoning. Kay, or its remnant low,
should continue to move on a generally westward heading to the south
of a mid-level ridge. The official track forecast is similar to the
previous one and not too different from the multi-model consensus.

FORECAST POSITIONS AND MAX WINDS

INIT 23/0300Z 22.0N 118.8W 35 KT 40 MPH
12H 23/1200Z 22.3N 119.9W 30 KT 35 MPH
24H 24/0000Z 22.6N 121.4W 25 KT 30 MPH
36H 24/1200Z 22.8N 123.0W 25 KT 30 MPH...POST-TROP/REMNT LOW
48H 25/0000Z 22.8N 124.8W 20 KT 25 MPH...POST-TROP/REMNT LOW
72H 26/0000Z...DISSIPATED

$$
Forecaster Pasch

[cycloneye]

TROPICAL DEPRESSION FIONA DISCUSSION NUMBER 26
NWS NATIONAL HURRICANE CENTER MIAMI FL AL062016
500 AM AST TUE AUG 23 2016

Fiona is barely holding on as a tropical cyclone with a small burst
of deep convection confined mainly to the southeastern quadrant due
to moderate to strong northwesterly vertical wind shear. The
initial intensity is being maintained at 30 kt based on a Dvorak
intensity estimate of 2.0/30 kt from TAFB, and an ADT estimate of
T2.2/32 kt from UW-CIMSS.

The initial motion is a little slower at 290/11 kt. Fiona is
forecast to gradually turn northwestward and decelerate as the
small cyclone moves toward and into a break in the Bermuda-Azores
ridge. The NHC forecast track is down the middle of the tightly
packed model guidance, and lies close to consensus track model TVCN.

Strong westerly to northwesterly vertical wind shear that has been
plaguing Fiona for the past several days is forecast to weaken
considerably during the next 36 hours, which would normally support
some strengthening. However, the small cyclone is expected to remain
embedded in a region of dry mid-level air with humidity values
less than 60 percent during that time, decreasing to less than 50
percent by 72 hours, which should inhibit the development of
persistent deep convection near the center. The result is that Fiona
is forecast to degenerate into a remnant low in 48 hours, if not
sooner. The official intensity forecast remains below the consensus
model IVCN and the SHIPS/LGEM models, and instead follows the
weakening trend depicted in the global models.

FORECAST POSITIONS AND MAX WINDS

INIT 23/0900Z 25.8N 63.4W 30 KT 35 MPH
12H 23/1800Z 26.2N 65.0W 30 KT 35 MPH
24H 24/0600Z 27.1N 67.0W 25 KT 30 MPH
36H 24/1800Z 28.1N 68.6W 25 KT 30 MPH
48H 25/0600Z 28.9N 69.5W 25 KT 30 MPH...POST-TROP/REMNT LOW
72H 26/0600Z 30.0N 70.8W 25 KT 30 MPH...POST-TROP/REMNT LOW
96H 27/0600Z 30.6N 71.6W 25 KT 30 MPH...POST-TROP/REMNT LOW
120H 28/0600Z...DISSIPATED

$$
Forecaster Stewart

[cycloneye]

POST-TROPICAL CYCLONE KAY DISCUSSION NUMBER 21
NWS NATIONAL HURRICANE CENTER MIAMI FL EP122016
200 PM PDT TUE AUG 23 2016

Kay has been devoid of deep convection for about 12 hours. Since
the system is over waters of around 24 deg C and forecast to soon
move over even cooler waters, deep convection is not expected to
return. On this basis, Kay is being declared a post-tropical
cyclone on this advisory. Dissipation is forecast by the global
models just after 24 hours.

The post-tropical cyclone is moving a little faster toward the
northwest or 310/11. A turn toward the west-northwest or west is
likely before the low dissipates tomorrow.

This is the last advisory from the National Hurricane Center on this
system. For additional information on the remnant low please see
High Seas Forecasts issued by the National Weather Service, under
AWIPS header NFDHSFEPI, WMO header FZPN02 KWBC, and on the web at
http://www.opc.ncep.noaa.gov/shtml/NFDHSFEPI.shtml.

FORECAST POSITIONS AND MAX WINDS

INIT 23/2100Z 23.5N 121.1W 30 KT 35 MPH...POST-TROP/REMNT LOW
12H 24/0600Z 23.6N 122.5W 25 KT 30 MPH...POST-TROP/REMNT LOW
24H 24/1800Z 23.7N 124.3W 20 KT 25 MPH...POST-TROP/REMNT LOW
36H 25/0600Z...DISSIPATED

$$
Forecaster Kimberlain