ATL: TROPICAL STORM BILL (03L)

[Brent]

BULLETIN
HURRICANE BILL ADVISORY NUMBER 9
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL032009
1100 AM AST MON AUG 17 2009

...BILL STRENGTHENING AS IT CONTINUES MOVING WEST-NORTHWESTWARD...

AT 1100 AM AST...1500 UTC...THE CENTER OF HURRICANE BILL WAS LOCATED
NEAR LATITUDE 14.1 NORTH...LONGITUDE 45.2 WEST OR ABOUT 1080 MILES
...1735 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 HAVE INCREASED TO NEAR 90 MPH...150
KM/HR...WITH HIGHER GUSTS. SOME STRENGTHENING IS FORECAST DURING
THE NEXT 48 HOURS...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.

THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 977 MB...28.85 INCHES.

...SUMMARY OF 1100 AM AST INFORMATION...
LOCATION...14.1N 45.2W
MAXIMUM SUSTAINED WINDS...90 MPH
PRESENT MOVEMENT...WEST-NORTHWEST OR 285 DEGREES AT 16 MPH
MINIMUM CENTRAL PRESSURE...977 MB

THE NEXT ADVISORY WILL BE ISSUED BY THE NATIONAL HURRICANE CENTER AT
500 PM AST.

$$
FORECASTER BRENNAN/ROBERTS

HURRICANE BILL FORECAST/ADVISORY NUMBER 9
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL032009
1500 UTC MON AUG 17 2009

HURRICANE CENTER LOCATED NEAR 14.1N 45.2W AT 17/1500Z
POSITION ACCURATE WITHIN 30 NM

PRESENT MOVEMENT TOWARD THE WEST-NORTHWEST OR 285 DEGREES AT 14 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 977 MB
MAX SUSTAINED WINDS 80 KT WITH GUSTS TO 100 KT.
64 KT....... 25NE 25SE 25SW 25NW.
50 KT....... 65NE 50SE 30SW 60NW.
34 KT.......125NE 105SE 75SW 125NW.
12 FT SEAS..250NE 180SE 110SW 200NW.
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 14.1N 45.2W AT 17/1500Z
AT 17/1200Z CENTER WAS LOCATED NEAR 13.9N 44.6W

FORECAST VALID 18/0000Z 14.7N 47.5W
MAX WIND 90 KT...GUSTS 110 KT.
64 KT... 30NE 30SE 30SW 30NW.
50 KT... 75NE 55SE 40SW 65NW.
34 KT...145NE 120SE 75SW 130NW.

FORECAST VALID 18/1200Z 15.5N 50.1W
MAX WIND 95 KT...GUSTS 115 KT.
64 KT... 35NE 35SE 35SW 35NW.
50 KT... 75NE 60SE 45SW 65NW.
34 KT...160NE 120SE 75SW 145NW.

FORECAST VALID 19/0000Z 16.6N 52.6W
MAX WIND 100 KT...GUSTS 120 KT.
64 KT... 40NE 35SE 35SW 40NW.
50 KT... 75NE 60SE 50SW 65NW.
34 KT...160NE 120SE 85SW 145NW.

FORECAST VALID 19/1200Z 18.0N 55.1W
MAX WIND 105 KT...GUSTS 130 KT.
50 KT... 75NE 65SE 55SW 70NW.
34 KT...160NE 120SE 90SW 150NW.

FORECAST VALID 20/1200Z 21.5N 60.0W
MAX WIND 110 KT...GUSTS 135 KT.
50 KT... 90NE 75SE 60SW 75NW.
34 KT...180NE 150SE 105SW 170NW.

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 21/1200Z 26.0N 64.0W
MAX WIND 110 KT...GUSTS 135 KT.

OUTLOOK VALID 22/1200Z 31.5N 66.5W
MAX WIND 105 KT...GUSTS 130 KT.

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 14.1N 45.2W

NEXT ADVISORY AT 17/2100Z

$$
FORECASTER BRENNAN/ROBERTS

HURRICANE BILL DISCUSSION NUMBER 9
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL032009
1100 AM AST MON AUG 17 2009

SATELLITE IMAGERY INDICATES THAT BILL CONTINUES TO INTENSIFY THIS
MORNING...WITH A UNIFORM CENTRAL DENSE OVERCAST AROUND THE CENTER.
THE INTENSITY IS RAISED TO 80 KT BASED ON A DVORAK T-NUMBER OF 4.5
FROM TAFB AT 1200 UTC. MICROWAVE IMAGERY FROM A 1132 UTC TRMM PASS
SHOWS SEVERAL CONVECTIVE BANDS SPIRALING AROUND THE CENTER...BUT NO
EVIDENCE OF AN EYE. BILL SHOULD PASS VERY CLOSE TO NOAA BUOY 41041
IN THE NEXT FEW HOURS...WHICH SHOULD HELP PROVIDE INFORMATION ON
THE WINDS AND CENTRAL PRESSURE OF THE CYCLONE.

THE OCEANIC AND ATMOSPHERIC ENVIRONMENT CONTINUES TO BE FAVORABLE
FOR INTENSIFICATION. WHILE THE SHIPS RI INDEX SHOWS A 35 PERCENT
CHANCE OF AN INCREASE OF 30 KT OR MORE IN THE NEXT 24 HOURS...
MICROWAVE IMAGERY SUGGESTS THAT BILL DOES NOT YET HAVE A WELL
DEFINED INNER CORE STRUCTURE. THE OFFICIAL INTENSITY FORECAST
IS ABOVE THE PREVIOUS PACKAGE FOR THE FIRST 36 HOURS DUE TO THE
OBSERVED INTENSIFICATION AND IS IN BEST AGREEMENT WITH SHIPS AND
LGEM. BEYOND THAT TIME...THE STATISTICAL MODELS SHOW THE INTENSITY
LEVELING OFF...WHILE THE HWRF AND GFDL SHOW STRENGTHENING THROUGH
THE END OF THE PERIOD. GIVEN THIS UNCERTAINTY...THE OFFICIAL
FORECAST SHOWS A PEAK IN INTENSITY AT DAYS 3 AND 4...AND A SLIGHT
DECREASE AT DAY 5.

BILL CONTINUES ON A HEADING OF 285/14...WITHIN THE DEEP-LAYER FLOW
OF A RIDGE EXTENDING WESTWARD OVER THE CENTRAL ATLANTIC FROM
AFRICA. GLOBAL MODELS AND WATER VAPOR IMAGERY INDICATE A PERSISTENT
MID-ATLANTIC TROUGH SITUATED ALONG 53W WHICH SHOULD CAUSE THE
CYCLONE TO TURN MORE TOWARD THE NORTHWEST BY DAY 3. BEYOND THIS
TIME...THE FLOW AROUND A LARGE MID- TO UPPER-LEVEL LOW THAT
DEVELOPS OVER THE EASTERN UNITED STATES SHOULD INDUCE A MORE
NORTH-NORTHWESTWARD TURN. ALL OF THE TRACK MODEL GUIDANCE...WITH
THE EXCEPTION OF THE UKMET...IS IN GOOD AGREEMENT ON THIS SCENARIO.
THE UKMET HAS A MUCH STRONGER SUBTROPICAL RIDGE THAN THE REST OF
THE GLOBAL MODELS AND THE GFS AND ECMWF ENSEMBLE MEANS. AS A
RESULT...THIS MODEL KEEPS BILL TOO FAR SOUTH TO FEEL THE EFFECTS OF
THE CLOSED LOW LATE IN THE PERIOD. THE OFFICIAL FORECAST IS
ESSENTIALLY AN UPDATE OF THE PREVIOUS PACKAGE THROUGH DAY 3...AND
IS SHIFTED SLIGHTLY TO THE RIGHT TOWARD THE MODEL CONSENSUS AT DAYS
4 AND 5.

THE INITIAL 34-KT WIND RADII WERE MODIFIED BASED ON A 0920 UTC
QUIKSCAT PASS.

FORECAST POSITIONS AND MAX WINDS

INITIAL 17/1500Z 14.1N 45.2W 80 KT
12HR VT 18/0000Z 14.7N 47.5W 90 KT
24HR VT 18/1200Z 15.5N 50.1W 95 KT
36HR VT 19/0000Z 16.6N 52.6W 100 KT
48HR VT 19/1200Z 18.0N 55.1W 105 KT
72HR VT 20/1200Z 21.5N 60.0W 110 KT
96HR VT 21/1200Z 26.0N 64.0W 110 KT
120HR VT 22/1200Z 31.5N 66.5W 105 KT

$$
FORECASTER BRENNAN/ROBERTS

[x-y-no]

meters per second?

Someone go fix that buoy!

You can get the winds in knots, but then you get the pressure in inches.

It'd be nice if NDBC allowed mixing metric pressure with English speed, but they don't.

[KWT]

Yep pressure is dropping away at that Bouy quite quickly. I wonder how deep the pressure can go, esp given it formed in a classic WPAC way so pressure may end up getting a little lower then you'd exect.

NHC keeps this as a category-1 for now as well.

[storms NC]

I hope not but chances of BILL pulling an ANDREW track is what? I hope it's slim to none!!!!!!!!

None - EC trough will see to that.

That Trough you are talking about is at the east coast and is moving off. Bill is to far down and to have an thing do do with the trough. JMO Not a Pro

[artist]

is it me or dose BILL look to be a double eyewall Hurricane???????

http://www.ssd.noaa.gov/goes/flt/t2/loop-vis.html

go to the water vapor loop. It appears to me Bill is gulping a large dose of dry air around his center.
http://weather.msfc.nasa.gov/GOES/goeseasthurrwv.html

[KWT]

There is certainly some sort of dry moat present around the center of convection so thats something to observe.

I think thats why the NHC have upped this to only 90mph rather then 100mph like the best track was suggesting.

[x-y-no]

I hope not but chances of BILL pulling an ANDREW track is what? I hope it's slim to none!!!!!!!!

None - EC trough will see to that.

That Trough you are talking about is at the east coast and is moving off. Bill is to far down and to have an thing do do with the trough. JMO Not a Pro

No. I'm talking about the next EC trough.

[KWT]

Its a combo of both the weakness around 50W that is allowing to turn WNW as it is and then as others have mentioned the trough coming off the EC.

[robbielyn]

oops wrong area wanted ana thread sorry

[Macrocane]

There is certainly some sort of dry moat present around the center of convection so thats something to observe.

I think thats why the NHC have upped this to only 90mph rather then 100mph like the best track was suggesting.

You're right it looks on visible like it's under an eyewall replacement cycle but it's the dry air wrapping around the center.

[x-y-no]

The only way the recurvature scenario fails is if the global models (aside from UKMET) are out to lunch and that weakness is much less pronounced than expected.

Even then, given how much latitude he's already gained, the trough digging on the EC on day 5 will pick him up. In the unlikely event that the UKMET is right, this could be an EC threat north of the Carolinas. In the far more likely case that the others are right, we're talking about Bermuda and possibly the Canadian maritimes.

[storms NC]

The only way the recurvature scenario fails is if the global models (aside from UKMET) are out to lunch and that weakness is much less pronounced than expected.

Even then, given how much latitude he's already gained, the trough digging on the EC on day 5 will pick him up. In the unlikely event that the UKMET is right, this could be an EC threat north of the Carolinas. In the far more likely case that the others are right, we're talking about Bermuda and possibly the Canadian maritimes.

I don't see Fla up to NC a hit with Bill. But just out to sea If he jumps on the train. If he Misses it then Fla up the EC.Timeing will be the factor with Bill. The troughs havn't been going that far south. Well have to wait and see. You never know with a Hurricane to what it wants to do. They have a mine of their own it seem at times

[Sanibel]

The models are definitely accurate. Bill is already into recurve and north of trop points.

First impressive Cape Verde cyclone of 2009.

[drezee]

Data just updated for 41041:

Latest pressure drop 7.0mb

That is the three hour pressure tendency, which is in the double digits now...

Anyone notice the 28+ ft seas at the buoy!!

[Sanibel]

Finally a system that shows that early development off Africa makes recurve more likely.

[KWT]

Yeah this one already is on the WNW motion, that track alone would make it hard for it to hit the US from this point, esp when east coast troughing has been quite a big feature this summer.

[BensonTCwatcher]

Yeah, just don't see any sign of the ridge filling back in the trough cutting off, blocking high, none of that. classic re-curve track in the making.

[Sanibel]

Watch out Bermuda!

[KWT]

Yeah Bermuda seems to be the biggest threat though the models seem to be shifting a touch further east of Bermuda. Still we shall see, I think Bermuda will get ome fun from Bill.

[HurricaneBelle]

Data just updated for 41041:

Latest pressure drop 7.0mb

That is the three hour pressure tendency, which is in the double digits now...

Anyone notice the 28+ ft seas at the buoy!!

I wonder if Bill knocked out the buoy, the 1550 report from it is now about 20 minutes late.