ATL: IAN - Post-Tropical - Discussion

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Re: ATL: IAN - Advisories

#121 Postby cycloneye » Tue Sep 13, 2016 9:47 am

TROPICAL STORM IAN DISCUSSION NUMBER 5
NWS NATIONAL HURRICANE CENTER MIAMI FL AL102016
1100 AM AST TUE SEP 13 2016

Ian remains a sheared tropical storm, with the low-cloud center
exposed to the south of the main area of deep convection. The
current intensity estimate remains 40 kt, since the system has not
become better organized since the time of the last scatterometer
pass. The strong shear over Ian is being produced by an upper-level
low a couple of hundred miles to the west-northwest. The global
models predict this low to open up into a negatively-tilted trough,
with some slight relaxation of the shear over the storm, in 24-36
hours. Therefore slight strengthening is shown by the official
forecast after 24 hours, in line with the latest model consensus.
The global model guidance depicts the cyclone to become frontal over
the north Atlantic by 96 hours, and this is also reflected in the
official forecast.

The tropical cyclone is moving north-northwestward at a slightly
faster forward speed, or around 330/11 kt. Ian is expected to
continue to move through a weakness in the mid-level subtropical
ridge over the next day or so. Then, an approaching trough in the
westerlies should cause the cyclone to turn north-northeastward and
accelerate. The official track forecast is a little faster than
the previous one, but not as fast as the latest GFS and ECMWF
model predictions.

FORECAST POSITIONS AND MAX WINDS

INIT 13/1500Z 25.4N 52.3W 40 KT 45 MPH
12H 14/0000Z 27.3N 53.0W 40 KT 45 MPH
24H 14/1200Z 29.9N 53.7W 40 KT 45 MPH
36H 15/0000Z 32.6N 53.8W 45 KT 50 MPH
48H 15/1200Z 35.5N 52.5W 50 KT 60 MPH
72H 16/1200Z 44.0N 42.4W 50 KT 60 MPH
96H 17/1200Z 54.0N 28.0W 50 KT 60 MPH...POST-TROP/EXTRATROP
120H 18/1200Z 62.0N 13.0W 45 KT 50 MPH...POST-TROP/EXTRATROP

$$
Forecaster Pasch
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Re: ATL: IAN - Advisories

#122 Postby cycloneye » Tue Sep 13, 2016 4:08 pm

BULLETIN
TROPICAL STORM IAN ADVISORY NUMBER 6
NWS NATIONAL HURRICANE CENTER MIAMI FL AL102016
500 PM AST TUE SEP 13 2016

...IAN MOVING OVER OPEN WATERS...
...NO THREAT TO LAND...


SUMMARY OF 500 PM AST...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...27.0N 52.7W
ABOUT 810 MI...1305 KM ESE OF BERMUDA
MAXIMUM SUSTAINED WINDS...45 MPH...75 KM/H
PRESENT MOVEMENT...NNW OR 346 DEGREES AT 16 MPH...26 KM/H
MINIMUM CENTRAL PRESSURE...1005 MB...29.68 INCHES




TROPICAL STORM IAN DISCUSSION NUMBER 6
NWS NATIONAL HURRICANE CENTER MIAMI FL AL102016
500 PM AST TUE SEP 13 2016

Ian continues to be sheared, and the low-level center is estimated
to be near the southern edge of a ragged-looking area of deep
convection. Since there has been no appreciable increase in the
organization of the tropical cyclone, the advisory intensity is held
at 40 kt, which is the mean of Dvorak intensity estimates from TAFB
and SAB. Given that the shear is forecast to remain strong enough
to inhibit strengthening for the next 24 hours or so, with some
relaxation thereafter, the official intensity forecast shows some
slow strengthening beginning tomorrow night. The official forecast
is in good agreement with the latest LGEM guidance. In 72 hours,
the global models predict the cyclone to have a frontal structure
over the north Atlantic, so the official forecast shows Ian as
extratropical by that time.

The storm has sped up a bit, and the initial motion is now near
340/14 kt. Over the next day or so, Ian will continue to move
through a weakness in the mid-level subtropical ridge. Later, when
the cyclone moves into the mid-latitude westerlies, a shortwave
trough approaching from the west should cause Ian to accelerate
north-northeastward to northeastward. The official track forecast
is faster than the previous one, but not quite as fast as the
latest ECMWF and GFS solutions. This is close to the multi-model
consensus and the FSU Superensemble.

FORECAST POSITIONS AND MAX WINDS

INIT 13/2100Z 27.0N 52.7W 40 KT 45 MPH
12H 14/0600Z 29.1N 53.3W 40 KT 45 MPH
24H 14/1800Z 31.8N 53.6W 40 KT 45 MPH
36H 15/0600Z 34.5N 53.0W 45 KT 50 MPH
48H 15/1800Z 37.5N 50.5W 50 KT 60 MPH
72H 16/1800Z 48.5N 37.0W 50 KT 60 MPH...POST-TROP/EXTRATROP
96H 17/1800Z 58.0N 22.0W 50 KT 60 MPH...POST-TROP/EXTRATROP
120H 18/1800Z 64.5N 8.0W 45 KT 50 MPH...POST-TROP/EXTRATROP

$$
Forecaster Pasch
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Re: ATL: IAN - Models

#123 Postby CrazyC83 » Tue Sep 13, 2016 7:29 pm

Is there any chance this could keep going straight up to the NNW, like say Juan in 2003?
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Re: ATL: IAN - Advisories

#124 Postby cycloneye » Tue Sep 13, 2016 10:02 pm

TROPICAL STORM IAN DISCUSSION NUMBER 7
NWS NATIONAL HURRICANE CENTER MIAMI FL AL102016
1100 PM AST TUE SEP 13 2016

Ian's cloud pattern has changed little in organization since this
afternoon. The low-level center remains patrially exposed to the
south of a fan-shaped mass of deep convection. This structure is
consistent with a deep-layer southwesterly vertical shear of nearly
40 kt associated with a mid- to upper-tropospheric cyclone to the
west of the cyclone. A 0018Z ASCAT pass showed reliable surface
winds near 45 kt well north of the center, which agrees with a TAFB
satellite classifciation of T3.0. On this basis, the initial
intensity is increased to 45 kt.

The initial motion estimate has been nudged a little more to the
right than earlier today and is now 345/11 kt. Ian should continue
to move generally northward into a weakness in the subtropical ridge
over the central Atlantic during the next 24 hours or so. A
significant acceleration toward the northeast should occur in about
36 hours when a shortwave trough moving through Atlantic Canada
approaches Ian. The NHC track forecast is adjusted to the right of
the previous one, especially after 24 hours, and is in agreement
with the the latest track consensus aids.

The SHIPS output indicates that the shear should decrease,
beginning in about 12 hours, roughly around the time that Ian
becomes co-located with the upper low to its west. The shear is
forecast to reach a relative minimum 24 hours later while the flow
aloft gradually becomes more diffluent. This baroclinic forcing is
expected to result in some intensification while Ian remains over
warm waters, though the cyclone could possess attributes of both a
tropical and an extratropical cyclone. Extratropical transition is
indicated in 2 to 3 days, with absorption by a larger extratropical
storm system over the North Atlantic likely around 72 hours. The
NHC intensity forecast is about the same as the previous one and
near the multi-model consensus.

FORECAST POSITIONS AND MAX WINDS

INIT 14/0300Z 27.6N 52.8W 45 KT 50 MPH
12H 14/1200Z 29.8N 53.2W 45 KT 50 MPH
24H 15/0000Z 32.3N 53.1W 50 KT 60 MPH
36H 15/1200Z 35.2N 51.3W 55 KT 65 MPH
48H 16/0000Z 39.4N 47.0W 55 KT 65 MPH
72H 17/0000Z 49.7N 33.7W 55 KT 65 MPH...POST-TROP/EXTRATROP
96H 18/0000Z...ABSORBED

$$
Forecaster Kimberlain
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Re: ATL: IAN - Advisories

#125 Postby cycloneye » Wed Sep 14, 2016 5:23 am

TROPICAL STORM IAN DISCUSSION NUMBER 8
NWS NATIONAL HURRICANE CENTER MIAMI FL AL102016
500 AM AST WED SEP 14 2016

The cloud pattern of Ian has changed little during the past several
hours. The low-level center of the tropical storm is completely
exposed and located more than 100 n mi south of the main area of
deep convection. This poor structure is the result of about 30 kt
of south-southwesterly vertical wind shear. The initial intensity
is held at 45 kt, in agreement with the earlier scatterometer data
and a Dvorak CI-number from TAFB.

Ian is moving northward at about 13 kt, and is being steered
by the southerly flow between a mid- to upper-level low to its west
and a ridge to its east. A northward to north-northeastward motion
at about the same forward speed is forecast during the next 24 hours
as the steering pattern more or less persists. After that time, a
shortwave trough is expected to move east of Atlantic Canada, and
that should cause Ian to turn northeastward and sharply accelerate
until the cyclone becomes absorbed by a large extratropical low in 3
to 4 days. The models are in good agreement, and the official
forecast lies closest to a consensus of the GFS and ECMWF models.

The strong shear that has been affecting Ian since genesis is
expected to let up some during the next 24 to 36 hours. The
predicted lower shear, fairly warm water, and baroclinic forcing
should allow Ian to strengthen a little during the next day or two.
Beyond a couple of days, Ian is forecast to move over sharply
cooler sea surface temperatures and into an environment of strong
shear. These conditions should cause the cyclone to lose
its tropical characteristics in 2 to 3 days. The NHC intensity
forecast is an update of the previous one, and lies near the middle
of the guidance envelope.

FORECAST POSITIONS AND MAX WINDS

INIT 14/0900Z 29.3N 53.0W 45 KT 50 MPH
12H 14/1800Z 31.3N 53.2W 50 KT 60 MPH
24H 15/0600Z 34.0N 52.3W 50 KT 60 MPH
36H 15/1800Z 37.2N 49.2W 55 KT 65 MPH
48H 16/0600Z 41.6N 43.6W 55 KT 65 MPH
72H 17/0600Z 53.4N 28.0W 55 KT 65 MPH...POST-TROP/EXTRATROP
96H 18/0600Z...DISSIPATED

$$
Forecaster Cangialosi
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Re: ATL: IAN - Advisories

#126 Postby cycloneye » Wed Sep 14, 2016 9:51 am

TROPICAL STORM IAN DISCUSSION NUMBER 9
NWS NATIONAL HURRICANE CENTER MIAMI FL AL102016
1100 AM AST WED SEP 14 2016

Ian's center has lost some definition and appears to have re-formed
north of the feature we had been tracking. The center remains
exposed to the south and southeast of the deep convection due to
almost 30 kt of vertical shear. Based on the Dvorak Current
Intensity number from TAFB, the estimated maximum winds remain 45
kt.

Due to the center's re-formation, the initial motion is a faster
355/17 kt. However, unless the center jumps again, this motion is
expected to stabilize back to around 14 kt in the next 12 hours. A
mid-/upper-level low to the west of Ian and a mid-tropospheric high
to the east should steer the cyclone northward and north-
northeastward during the next day or so. After that time, Ian is
expected to accelerate toward the northeast as it gets picked up by
a progressive mid-latitude trough moving eastward from Atlantic
Canada. The new track guidance agrees on this scenario, although a
slight westward shift in the official track forecast was required,
probably due to the updated initial position. The new NHC forecast
is very close to the TVCN multi-model consensus.

Although the vertical shear is expected to decrease only slightly,
marginally warm waters and Ian's baroclinic interaction with the
mid-/upper-level low to its west are expected to foster some
strengthening during the next 36 hours. Ian is then expected to
lose the last of its tropical characteristics and become
extratropical by 48 hours and then be absorbed by another
extratropical low by 72 hours. This forecast follows guidance
provided by the Ocean Prediction Center and is closest to the
scenario shown by the ECMWF model. There is still some uncertainty
in this thinking, however, since the GFS, UKMET, and Canadian models
make Ian the dominant extratropical low over the far northern
Atlantic.

FORECAST POSITIONS AND MAX WINDS

INIT 14/1500Z 31.4N 53.0W 45 KT 50 MPH
12H 15/0000Z 33.7N 52.8W 50 KT 60 MPH
24H 15/1200Z 36.7N 51.1W 50 KT 60 MPH
36H 16/0000Z 40.2N 46.9W 55 KT 65 MPH
48H 16/1200Z 45.4N 39.8W 55 KT 65 MPH...POST-TROP/EXTRATROP
72H 17/1200Z...DISSIPATED

$$
Forecaster Berg
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Re: ATL: IAN - Advisories

#127 Postby cycloneye » Wed Sep 14, 2016 3:34 pm

TROPICAL STORM IAN DISCUSSION NUMBER 10
NWS NATIONAL HURRICANE CENTER MIAMI FL AL102016
500 PM AST WED SEP 14 2016

Ian does not look much like a tropical storm this afternoon with all
of its convection well removed from a rather broad and disorganized
low-level circulation. In fact, Ian has some subtropical
characteristics, including its collocation with an upper-level low
and a large radius of maximum wind. However, these features could
be temporary. The initial wind speed remains 45 kt based on
continuity.

An uncertain estimate of the initial motion is 350/15. Ian should
be steered northward and northeastward during the next day or so as
it moves around the subtropical ridge. The cyclone is expected to
accelerate quickly toward the northeast as it gets picked up by a
mid-latitude trough moving eastward from Atlantic Canada. Similar to
the previous advisory, a slight westward shift in the official track
forecast was required mostly due to the updated initial position.
Otherwise, the forecast is a bit faster than the model consensus.

Ian does not have much time left to intensify as a tropical cyclone
since it should move over colder waters by tomorrow evening. It does
have a narrow window of lower shear during the next day, although
given its current poor organization and structure, no significant
intensification is forecast during that time. Ian is then expected
to lose its tropical characteristics by 36 hours and be absorbed by
another extratropical low by 72 hours. The only significant change
to the intensity forecast is for a stronger extratropical phase, but
not quite as strong as the 12 UTC GFS solution.

FORECAST POSITIONS AND MAX WINDS

INIT 14/2100Z 32.9N 53.6W 45 KT 50 MPH
12H 15/0600Z 34.8N 53.0W 50 KT 60 MPH
24H 15/1800Z 38.0N 50.0W 50 KT 60 MPH
36H 16/0600Z 42.7N 44.0W 55 KT 65 MPH...POST-TROP/EXTRATROP
48H 16/1800Z 49.0N 35.0W 60 KT 70 MPH...POST-TROP/EXTRATROP
72H 17/1800Z...DISSIPATED

$$
Forecaster Blake
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Re: ATL: IAN - Advisories

#128 Postby cycloneye » Wed Sep 14, 2016 9:55 pm

BULLETIN
TROPICAL STORM IAN ADVISORY NUMBER 11
NWS NATIONAL HURRICANE CENTER MIAMI FL AL102016
1100 PM AST WED SEP 14 2016

...IAN MOVING NORTH-NORTHEASTWARD OVER THE NORTH ATLANTIC...


SUMMARY OF 1100 PM AST...0300 UTC...INFORMATION
-----------------------------------------------
LOCATION...33.9N 53.4W
ABOUT 670 MI...1075 KM ENE OF BERMUDA
MAXIMUM SUSTAINED WINDS...50 MPH...85 KM/H
PRESENT MOVEMENT...NNE OR 15 DEGREES AT 14 MPH...22 KM/H
MINIMUM CENTRAL PRESSURE...998 MB...29.47 INCHES


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


DISCUSSION AND 48-HOUR OUTLOOK
------------------------------
At 1100 PM AST (0300 UTC), the center of Tropical Storm Ian was
located near latitude 33.9 North, longitude 53.4 West. Ian is moving
toward the north-northeast near 14 mph (22 km/h), and this motion is
expected to continue tonight. A turn toward the northeast with an
increase in forward speed is expected by late Thursday.

Maximum sustained winds are near 50 mph (85 km/h) with higher gusts.
Some strengthening is forecast during the next day or so, but Ian
is expected to lose its tropical characteristics on Friday.

Tropical-storm-force winds extend outward up to 230 miles (370 km)
from the center.

The estimated minimum central pressure is 998 mb (29.47 inches).


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


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

$$
Forecaster Stewart
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Re: ATL: IAN - Advisories

#129 Postby cycloneye » Thu Sep 15, 2016 5:26 am

TROPICAL STORM IAN DISCUSSION NUMBER 12
NWS NATIONAL HURRICANE CENTER MIAMI FL AL102016
500 AM AST THU SEP 15 2016

Ian continues to have a structure somewhat resembling a subtropical
cyclone, with the low-level center situated beneath an upper-level
low and a cloud pattern featuring a broken band of convection.
However, there is still some moderate to deep convection not too far
from the center, and the most recent AMSU pass still showed a deep
warm core structure. The initial intensity remains 45 kt in
agreement with the latest satellite classification of ST3.5 from
TAFB. Ian is running out of time to strengthen via diabatic
processes, and most of the strengthening shown here is expected to
be due to baroclinic effects, especially given the current
convective structure. By 24 hours, strong shear and cool SSTs
should result in Ian being post-tropical, and the cyclone should be
fully extratropical by 36 hours. The intensity forecast is based
mainly on the global models and guidance from the Ocean Prediction
Center, and shows the post-tropical cyclone intensifying to near
hurricane strength before it's absorbed by a larger extratropical
low in 48 hours.

The initial motion estimate is 025/17. Ian should accelerate
northeastward ahead of a large upper-level trough moving eastward
across the northwestern Atlantic during the next 36 hours before
being absorbed. The new NHC track forecast is similar to the
previous one and near the middle of the guidance envelope.

The initial 34-kt wind radii were adjusted based on a partial ASCAT
pass from around 0100 UTC.

FORECAST POSITIONS AND MAX WINDS

INIT 15/0900Z 35.5N 52.4W 45 KT 50 MPH
12H 15/1800Z 38.3N 49.8W 50 KT 60 MPH
24H 16/0600Z 43.0N 43.7W 55 KT 65 MPH...POST-TROPICAL
36H 16/1800Z 49.1N 35.5W 60 KT 70 MPH...POST-TROP/EXTRATROP
48H 17/0600Z...ABSORBED BY ANOTHER EXTRATROPICAL LOW

$$
Forecaster Brennan
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Re: ATL: IAN - Advisories

#130 Postby cycloneye » Thu Sep 15, 2016 9:46 am

TROPICAL STORM IAN DISCUSSION NUMBER 13
NWS NATIONAL HURRICANE CENTER MIAMI FL AL102016
1100 AM AST THU SEP 15 2016

After looking more like a subtropical cyclone than a tropical
cyclone for most of the past 24 hours, there has recently been an
increase in convective banding over the eastern semicircle of Ian.
The initial intensity remains 45 kt based on a subtropical cyclone
intensity estimate from TAFB. Ian is forecast to merge with the
westerlies and undergo extratropical transition during the next
36-48 hours, and in the process it is expected to strengthen to at
least storm-force before it is absorbed by another extratropical
low. The new intensity forecast is an update of the previous
forecast based on the global models and guidance from the Ocean
Prediction Center

Ian is accelerating northeastward and the initial motion is now
040/21. A northeastward motion with an additional increase in
forward speed is expected before the cyclone is absorbed. The new
forecast track is near the center of the tightly clustered track
guidance.


FORECAST POSITIONS AND MAX WINDS

INIT 15/1500Z 37.2N 50.5W 45 KT 50 MPH
12H 16/0000Z 40.3N 46.8W 55 KT 65 MPH
24H 16/1200Z 45.6N 39.6W 60 KT 70 MPH...POST-TROPICAL
36H 17/0000Z 51.5N 32.0W 60 KT 70 MPH...POST-TROP/EXTRATROP
48H 17/1200Z...MERGED WITH EXTRATROPICAL LOW

$$
Forecaster Beven
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Re: ATL: IAN - Tropical Storm - Discussion

#131 Postby HurricaneRyan » Thu Sep 15, 2016 10:31 am

This thread is dead, lol.
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Re: ATL: IAN - Advisories

#132 Postby cycloneye » Thu Sep 15, 2016 3:45 pm

TROPICAL STORM IAN DISCUSSION NUMBER 14
NWS NATIONAL HURRICANE CENTER MIAMI FL AL102016
500 PM AST THU SEP 15 2016

A scatterometer overpass shows that the circulation of Ian is losing
definition as the cyclone accelerates northeastward, with the system
elongating north to south. The scatterometer did not sample the
maximum winds, and the subtropical cyclone satellite intensity
estimates are unchanged. Based on this, the initial intensity
remains a likely conservative 45 kt. Ian is forecast to merge with
a baroclinic zone and undergo extratropical transition during the
next 12-36 hours, and in the process it is expected to strengthen to
at least storm-force before it is absorbed by another extratropical
low. The new intensity forecast is an update of the previous
forecast based on the global models and guidance from the Ocean
Prediction Center.

Ian continues to accelerate northeastward and the initial motion is
now 040/30 kt. A northeastward motion with an additional increase
in forward speed is expected before the cyclone is absorbed. The
new forecast track remains near the center of the tightly clustered
track guidance.

FORECAST POSITIONS AND MAX WINDS

INIT 15/2100Z 39.6N 47.7W 45 KT 50 MPH
12H 16/0600Z 43.2N 42.7W 55 KT 65 MPH...POST-TROPICAL
24H 16/1800Z 49.5N 34.5W 60 KT 70 MPH...POST-TROP/EXTRATROP
36H 17/0600Z 55.5N 26.5W 60 KT 70 MPH...POST-TROP/EXTRATROP
48H 17/1800Z 61.0W 18.5W 60 KT 70 MPH...POST-TROP/EXTRATROP
72H 18/1800Z...ABSORBED BY EXTRATROPICAL LOW

$$
Forecaster Beven
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Re: ATL: IAN - Tropical Storm - Discussion

#133 Postby Hammy » Thu Sep 15, 2016 6:51 pm

Given the satellite appearance I'm wondering if this could make a run at hurricane intensity before becoming extratopical.
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Re: ATL: IAN - Tropical Storm - Discussion

#134 Postby Hammy » Thu Sep 15, 2016 8:15 pm

Up to 50kt as per latest BT.
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Re: ATL: IAN - Advisories

#135 Postby cycloneye » Thu Sep 15, 2016 10:32 pm

TROPICAL STORM IAN DISCUSSION NUMBER 15
NWS NATIONAL HURRICANE CENTER MIAMI FL AL102016
1100 PM AST THU SEP 15 2016

Ian has continued to accelerate northeastward within deep-layer
southwesterly flow ahead of an approaching cold front and strong
shortwave trough, and this general motion is expected for the next
2 days until the system becomes absorbed by a larger extratropical
low. The new track forecast is essentially just an update of the
previous advisory track and remains near the center of the tightly
clustered NHC model guidance, close to the GFS and ECMWF consensus.

The initial intensity remains at 45 kt based a 16/0034Z ASCAT-B
overpass that contained few 43-kt wind vectors southeast of the
well-defined low-level center. Ian is forecast to merge with
a baroclinic zone and undergo extratropical transition during the
next 12-36 hours, and in the process it is expected to strengthen to
at least storm-force before it is absorbed by another extratropical
low. The new intensity forecast is the same as the previous
advisory based on the global models and guidance from the Ocean
Prediction Center.

FORECAST POSITIONS AND MAX WINDS

INIT 16/0300Z 42.9N 44.9W 45 KT 50 MPH
12H 16/1200Z 46.9N 39.5W 55 KT 65 MPH...POST-TROPICAL
24H 17/0000Z 53.3N 31.4W 60 KT 70 MPH...POST-TROP/EXTRATROP
36H 17/1200Z 58.9N 23.4W 55 KT 65 MPH...POST-TROP/EXTRATROP
48H 18/0000Z 63.3N 15.6W 50 KT 60 MPH...POST-TROP/EXTRATROP
72H 19/0000Z...ABSORBED

$$
Forecaster Stewart
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arlwx
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Re: ATL: IAN - Advisories

#136 Postby arlwx » Fri Sep 16, 2016 4:10 am

TROPICAL STORM IAN DISCUSSION NUMBER 16
NWS NATIONAL HURRICANE CENTER MIAMI FL AL102016
500 AM AST FRI SEP 16 2016

Cloud tops have warmed near the center of Ian overnight, but the
cloud pattern in geostationary imagery still resembles that of a
tropical cyclone. A small mid-level eye and a banding convective
structure are also seen in a 0417 UTC AMSR-2 overpass from GCOM-W1.
The initial intensity is set to 50 kt based on the latest ST3.0
classification from TAFB and the fast forward speed of the cyclone,
which now exceeds 40 kt. Ian should become extratropical within 12
hours and then be absorbed by another front near or northeast of
Iceland in about 48 hours, as indicated by the latest ECMWF and
UKMET model solutions.

The AMSR-2 pass mentioned above and a 0544 UTC SSM/I pass were
helpful in locating the low-level center of Ian, and the initial
motion estimate is a somewhat uncertain 040/42. The cyclone should
continue moving quickly northeastward ahead of a large upper-level
trough until it is absorbed. The new NHC track forecast is based on
a blend of the tightly clustered global model guidance.

The track, intensity, and wind radii forecasts are based largely on
guidance from the Ocean Prediction Center.

FORECAST POSITIONS AND MAX WINDS

INIT 16/0900Z 45.2N 40.8W 50 KT 60 MPH
12H 16/1800Z 50.1N 34.4W 50 KT 60 MPH...POST-TROP/EXTRATROP
24H 17/0600Z 57.2N 25.4W 50 KT 60 MPH...POST-TROP/EXTRATROP
36H 17/1800Z 61.8N 18.7W 50 KT 60 MPH...POST-TROP/EXTRATROP
48H 18/0600Z...ABSORBED

$$
Forecaster Brennan
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Kazmit
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Re: ATL: IAN - Tropical Storm - Discussion

#137 Postby Kazmit » Fri Sep 16, 2016 5:02 am

I'm surprised Ian is still able to have some tropical characteristics at the latitude it's at. Should be post-tropical by this evening...
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I am only a tropical weather enthusiast. My predictions are not official and may or may not be backed by sound meteorological data. For official information, please refer to the NHC and NWS products.


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