Thread: Hurricane Bill -Cat 1- east of Nova Scotia

Tropical storm bill forecast/advisory number 4
nws tpc/national hurricane center miami fl al032009
0900 utc sun aug 16 2009

tropical storm center located near 11.4n 37.2w at 16/0900z
position accurate within 30 nm

present movement toward the west or 270 degrees at 11 kt

estimated minimum central pressure 1002 mb
max sustained winds 40 kt with gusts to 50 kt.
34 kt....... 60ne 25se 0sw 25nw.
12 ft seas.. 90ne 25se 0sw 60nw.
Winds and seas vary greatly in each quadrant. Radii in nautical
miles are the largest radii expected anywhere in that quadrant.

Repeat...center located near 11.4n 37.2w at 16/0900z
at 16/0600z center was located near 11.4n 36.6w

forecast valid 16/1800z 11.8n 39.3w
max wind 45 kt...gusts 55 kt.
34 kt... 60ne 45se 30sw 45nw.

Forecast valid 17/0600z 12.5n 41.9w
max wind 50 kt...gusts 60 kt.
50 kt... 30ne 15se 0sw 15nw.
34 kt... 75ne 60se 30sw 60nw.

Forecast valid 17/1800z 13.4n 44.7w
max wind 60 kt...gusts 75 kt.
50 kt... 30ne 30se 0sw 30nw.
34 kt... 90ne 60se 45sw 75nw.

Forecast valid 18/0600z 14.3n 47.5w
max wind 70 kt...gusts 85 kt.
50 kt... 45ne 30se 30sw 45nw.
34 kt... 90ne 60se 45sw 75nw.

Forecast valid 19/0600z 16.5n 53.0w
max wind 85 kt...gusts 105 kt.
50 kt... 60ne 45se 30sw 45nw.
34 kt...105ne 75se 60sw 90nw.

Extended outlook. Note...errors for track have averaged near 225 nm
on day 4 and 300 nm on day 5...and for intensity near 20 kt each day

outlook valid 20/0600z 19.0n 58.5w
max wind 95 kt...gusts 115 kt.

Outlook valid 21/0600z 22.0n 64.0w
max wind 100 kt...gusts 120 kt.

Request for 3 hourly ship reports within 300 miles of 11.4n 37.2w

next advisory at 16/1500z

$$
forecaster berg

Tropical storm bill discussion number 4
nws tpc/national hurricane center miami fl al032009
500 am ast sun aug 16 2009

the center of bill has been difficult to find this morning...and a
0419 utc amsr-e pass indicated that it has either slowed down or
has been re-forming closer to the deep convection. Dvorak
t-numbers are now 3.0 from tafb and 2.5 from sab...so the initial
intensity is raised to 40 kt. Bill is expected to gradually
strengthen over the next couple of days...and the official forecast
follows the upward trend noted in the intensity guidance. Bill is
now expected to reach major hurricane status by day 5...but it
should be noted that the 100 kt shown in the forecast is still
below the intensity consensus and well below the hwrf model. This
is to account for increased vertical shear that may develop by days
4 and 5...as indicated in the ships guidance.

The initial motion is an uncertain 270/11. Bill is expected to
gradually gain latitude and turn to the west-northwest over the
next few days. The new suite of model guidance has shifted a
little north of the previous guidance envelope as most of the
models appear to be showing the development of a deep mid- to
upper-level trough over the eastern united states at the end of the
forecast period. Most of the models...with the exception of the
ukmet as a southern outlier...are in remarkably good agreement
through day 5.

Forecast positions and max winds

initial 16/0900z 11.4n 37.2w 40 kt
12hr vt 16/1800z 11.8n 39.3w 45 kt
24hr vt 17/0600z 12.5n 41.9w 50 kt
36hr vt 17/1800z 13.4n 44.7w 60 kt
48hr vt 18/0600z 14.3n 47.5w 70 kt
72hr vt 19/0600z 16.5n 53.0w 85 kt
96hr vt 20/0600z 19.0n 58.5w 95 kt
120hr vt 21/0600z 22.0n 64.0w 100 kt

$$
forecaster berg

000
wtnt33 knhc 160856
tcpat3
bulletin
tropical storm bill advisory number 4
nws tpc/national hurricane center miami fl al032009
500 am ast sun aug 16 2009

...bill strengthens a little...

At 500 am ast...0900 utc...the center of tropical storm bill was
located near latitude 11.4 north...longitude 37.2 west or about 1640
miles...2645 km...east of the lesser antilles.

Bill is moving toward the west near 13 mph...20 km/hr. A gradual
turn toward the west-northwest with an increase in forward speed is
expected during the next 24 to 48 hours.

Maximum sustained winds have increased to near 45 mph...75
km/hr...with higher gusts. Some strengthening is forecast...and
bill is expected to become a hurricane during the next few days.

Tropical storm force winds extend outward up to 70 miles...110 km
from the center.

Estimated minimum central pressure is 1002 mb...29.59 inches.

...summary of 500 am ast information...
Location...11.4n 37.2w
maximum sustained winds...45 mph
present movement...west or 270 degrees at 13 mph
minimum central pressure...1002 mb

the next advisory will be issued by the national hurricane center at
1100 am ast.

$$
forecaster berg

Tropical storm bill discussion number 3
nws tpc/national hurricane center miami fl al032009
1100 pm ast sat aug 15 2009

satellite images continue to show that bill is gradually becoming
better organized with numerous convective banding features.
However...the cyclone lacks an inner core and deep convection near
the center. Initial intensity is kept at 35 knots which is a blend
of the dvorak classifications and quikscat data. With the
conducive environment ahead...bill is forecast to become a
hurricane in a couple of days and become even stronger thereafter.
This is consistent with ships and both the gfdl/hwrf model pair.

Bill is moving westward or 270 degrees at 14 knots. The cyclone is
well-embedded in the tropical trade winds and will continue on this
general track with a gradual turn to the west-northwest. The ecmwf
was the leader showing a gradual northward trend ahead of a trough
over the eastern united states a few runs ago. Now...the rest of
the models...with the exception of the uk model...are following the
ecmwf tune...and all turn bill more the west-northwest and northwest
by the end of the forecast period. Based on this shift in the
guidance...the official forecast was also shifted a little
northward and is in the middle of the tightly packed guidance
envelope.


Forecast positions and max winds

initial 16/0300z 11.3n 36.6w 35 kt
12hr vt 16/1200z 11.2n 38.7w 40 kt
24hr vt 17/0000z 12.0n 41.5w 50 kt
36hr vt 17/1200z 12.8n 44.0w 55 kt
48hr vt 18/0000z 14.0n 47.0w 65 kt
72hr vt 19/0000z 15.5n 52.5w 75 kt
96hr vt 20/0000z 18.0n 58.5w 85 kt
120hr vt 21/0000z 21.0n 64.0w 95 kt

$$
forecaster avila

000
wtnt33 knhc 161441
tcpat3
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tropical storm bill advisory number 5
nws tpc/national hurricane center miami fl al032009
1100 am ast sun aug 16 2009

...bill strengthening over the central tropical atlantic ocean...

At 1100 am ast...1500 utc...the center of tropical storm bill was
located near latitude 12.1 north...longitude 38.4 west or about 1555
miles...2500 km...east of the lesser antilles.

Bill is moving toward the west-northwest near 16 mph...26 km/hr...
And this general motion is expected to continue for the next couple
of days.

maximum sustained winds are near 60 mph...95 km/hr...with higher
gusts. Strengthening is forecast during the next 48 hours and bill
could become a hurricane on monday.

Tropical storm force winds extend outward up to 140 miles...220 km
from the center.

The estimated minimum central pressure is 997 mb...29.44 inches.

...summary of 1100 am ast information...
Location...12.1n 38.4w
maximum sustained winds...60 mph
present movement...west-northwest or 285 degrees at 16 mph
minimum central pressure...997 mb

the next advisory will be issued by the national hurricane center at
500 pm ast.

$$
forecaster blake

000
wtnt33 knhc 162039
tcpat3
bulletin
tropical storm bill advisory number 6
nws tpc/national hurricane center miami fl al032009
500 pm ast sun aug 16 2009

...bill likely to become a hurricane tonight or on monday...

At 500 pm ast...2100 utc...the center of tropical storm bill was
located near latitude 12.8 north...longitude 40.0 west or about 1440
miles...2315 km...east of the lesser antilles.

Bill is moving toward the west-northwest near 16 mph...26 km/hr...
And this motion is expected to continue for the next couple of days.

Maximum sustained winds are near 65 mph...100 km/hr...with higher
gusts. Bill is expected to become a hurricane later tonight or
tomorrow.

Tropical storm force winds extend outward up to 140 miles...220 km
from the center.

The estimated minimum central pressure is 994 mb...29.35 inches.

...summary of 500 pm ast information...
Location...12.8n 40.0w
maximum sustained winds...65 mph
present movement...west-northwest or 285 degrees at 16 mph
minimum central pressure...994 mb

the next advisory will be issued by the national hurricane center at
1100 pm ast.

$$
forecaster blake

Bill is now a
HURRICANE

000
wtnt33 knhc 170854
tcpat3
bulletin
hurricane bill advisory number 8
nws tpc/national hurricane center miami fl al032009
500 am ast mon aug 17 2009

...bill now a hurricane...the first of the 2009 atlantic season...

At 500 am ast...0900 utc...the center of hurricane bill was located
near latitude 13.8 north...longitude 44.0 west or about 1160 miles
...1870 km...east of the lesser antilles.

Bill is moving quickly toward the west-northwest near 22 mph...35
km/hr...and this general motion is expected to continue for the
next 24 to 48 hours.

Maximum sustained winds have increased to near 75 mph...120 km/hr.
Strengthening is forecast during the next day or two...and bill
could become a major hurricane by wednesday.

Hurricane force winds extend outward up to 30 miles...45 km...from
the center...and tropical storm force winds extend outward up to 145
miles...230 km.

Estimated minimum central pressure is 987 mb...29.15 inches.

...summary of 500 am ast information...
Location...13.8n 44.0w
maximum sustained winds...75 mph
present movement...west-northwest or 285 degrees at 22 mph
minimum central pressure...987 mb

the next advisory will be issued by the national hurricane center at
1100 am ast.

$$
forecaster kimberlain/brown