ATL: TROPICAL STORM BILL (03L)

[Brent]

BULLETIN
HURRICANE BILL ADVISORY NUMBER 26
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL032009
500 PM AST FRI AUG 21 2009

...HURRICANE BILL A LITTLE WEAKER...COULD REGAIN SOME STRENGTH ON
SATURDAY...

A TROPICAL STORM WARNING AND A HURRICANE WATCH ARE IN EFFECT FOR
BERMUDA.

INTERESTS ALONG THE COAST OF NEW ENGLAND AND IN THE CANADIAN
MARITIMES SHOULD MONITOR THE PROGRESS OF BILL.

FOR STORM INFORMATION SPECIFIC TO YOUR AREA IN THE UNITED
STATES...PLEASE MONITOR PRODUCTS ISSUED BY YOUR LOCAL NATIONAL
WEATHER SERVICE FORECAST OFFICE. FOR STORM INFORMATION SPECIFIC TO
YOUR AREA OUTSIDE OF THE UNITED STATES...PLEASE MONITOR PRODUCTS
ISSUED BY YOUR NATIONAL METEOROLOGICAL SERVICE.

AT 500 PM AST...2100 UTC...THE CENTER OF HURRICANE BILL WAS LOCATED
NEAR LATITUDE 29.4 NORTH...LONGITUDE 66.9 WEST OR ABOUT 235 MILES...
380 KM...SOUTH-SOUTHWEST OF BERMUDA AND ABOUT 640 MILES...1035 KM...
SOUTHEAST OF CAPE HATTERAS NORTH CAROLINA.

BILL IS MOVING TOWARD THE NORTH-NORTHWEST NEAR 20 MPH...32 KM/HR. A
GRADUAL TURN TOWARD THE NORTH IS EXPECTED TONIGHT AND SATURDAY. ON
THE FORECAST TRACK...THE CORE OF HURRICANE BILL IS EXPECTED TO PASS
OVER THE OPEN WATERS BETWEEN BERMUDA AND THE EAST COAST OF THE
UNITED STATES ON SATURDAY.

MAXIMUM SUSTAINED WINDS ARE NEAR HAVE DECREASED TO NEAR 105
MPH...165 KM/HR...WITH HIGHER GUSTS. BILL IS A CATEGORY TWO
HURRICANE ON THE SAFFIR-SIMPSON SCALE. SOME STRENGTHENING IS STILL
POSSIBLE TONIGHT OR SATURDAY.

HURRICANE FORCE WINDS EXTEND OUTWARD UP TO 85 MILES...140 KM...FROM
THE CENTER...AND TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 275
MILES...445 KM.

THE MINIMUM CENTRAL PRESSURE REPORTED BY AN AIR FORCE RECONNAISSANCE
AIRCRAFT WAS 954 MB...28.17 INCHES.

BILL IS EXPECTED TO PRODUCE TOTAL RAIN ACCUMULATIONS OF 1 TO 3
INCHES OVER BERMUDA...WITH MAXIMUM AMOUNTS OF 5 INCHES.

THE BERMUDA WEATHER SERVICE HAS INDICATED THAT THE STORM TIDE WILL
RAISE WATER LEVELS BY AS MUCH AS 3 FEET ABOVE GROUND LEVEL ALONG
THE COAST...ALONG WITH LARGE AND DANGEROUS BATTERING WAVES...IN
ADVANCE OF BILL.

LARGE SWELLS GENERATED BY THIS HURRICANE ARE AFFECTING PUERTO
RICO...HISPANIOLA...THE BAHAMAS...AND BERMUDA...AND SHOULD BEGIN
AFFECTING MOST OF THE U.S. EAST COAST AND THE ATLANTIC MARITIMES OF
CANADA DURING THE NEXT DAY OR TWO. THESE SWELLS WILL LIKELY CAUSE
EXTREMELY DANGEROUS SURF AND LIFE-THREATENING RIP CURRENTS.

...SUMMARY OF 500 PM AST INFORMATION...
LOCATION...29.4N 66.9W
MAXIMUM SUSTAINED WINDS...105 MPH
PRESENT MOVEMENT...NORTH-NORTHWEST OR 340 DEGREES AT 20 MPH
MINIMUM CENTRAL PRESSURE...954 MB

AN INTERMEDIATE ADVISORY WILL BE ISSUED BY THE NATIONAL HURRICANE
CENTER AT 800 PM AST FOLLOWED BY THE NEXT COMPLETE ADVISORY AT 1100
PM AST.

$$
FORECASTER AVILA

HURRICANE BILL FORECAST/ADVISORY NUMBER 26
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL032009
2100 UTC FRI AUG 21 2009

A TROPICAL STORM WARNING AND A HURRICANE WATCH ARE IN EFFECT FOR
BERMUDA.

INTERESTS ALONG THE COAST OF NEW ENGLAND AND IN THE CANADIAN
MARITIMES SHOULD MONITOR THE PROGRESS OF BILL.

HURRICANE CENTER LOCATED NEAR 29.4N 66.9W AT 21/2100Z
POSITION ACCURATE WITHIN 10 NM

PRESENT MOVEMENT TOWARD THE NORTH-NORTHWEST OR 340 DEGREES AT 17 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 954 MB
EYE DIAMETER 15 NM
MAX SUSTAINED WINDS 90 KT WITH GUSTS TO 110 KT.
64 KT....... 75NE 30SE 20SW 60NW.
50 KT.......100NE 100SE 50SW 120NW.
34 KT.......240NE 200SE 100SW 175NW.
12 FT SEAS..450NE 360SE 380SW 320NW.
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 29.4N 66.9W AT 21/2100Z
AT 21/1800Z CENTER WAS LOCATED NEAR 28.6N 66.6W

FORECAST VALID 22/0600Z 31.7N 68.0W
MAX WIND 100 KT...GUSTS 120 KT.
64 KT... 75NE 30SE 20SW 30NW.
50 KT...100NE 100SE 50SW 100NW.
34 KT...240NE 200SE 100SW 175NW.

FORECAST VALID 22/1800Z 35.1N 68.4W
MAX WIND 100 KT...GUSTS 120 KT.
64 KT... 75NE 30SE 20SW 30NW.
50 KT...100NE 100SE 50SW 100NW.
34 KT...240NE 200SE 100SW 175NW.

FORECAST VALID 23/0600Z 39.0N 67.2W
MAX WIND 85 KT...GUSTS 105 KT.
64 KT... 75NE 25SE 20SW 30NW.
50 KT...100NE 100SE 30SW 90NW.
34 KT...240NE 200SE 100SW 150NW.

FORECAST VALID 23/1800Z 43.0N 64.0W
MAX WIND 75 KT...GUSTS 90 KT.
50 KT...100NE 100SE 30SW 90NW.
34 KT...240NE 240SE 100SW 150NW.

FORECAST VALID 24/1800Z 49.5N 47.0W...EXTRATROPICAL
MAX WIND 50 KT...GUSTS 60 KT.
50 KT...100NE 100SE 30SW 90NW.
34 KT...225NE 250SE 100SW 150NW.

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 25/1800Z 54.5N 20.0W...EXTRATROPICAL
MAX WIND 45 KT...GUSTS 55 KT.

OUTLOOK VALID 26/1800Z 60.0N 6.0W...EXTRATROPICAL
MAX WIND 35 KT...GUSTS 45 KT.

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 29.4N 66.9W

NEXT ADVISORY AT 22/0300Z

$$
FORECASTER AVILA

HURRICANE BILL DISCUSSION NUMBER 26
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL032009
500 PM AST FRI AUG 21 2009

AN AIR FORCE HURRICANE HUNTER AIRCRAFT REACHED BILL THIS
AFTERNOON AND FOUND THAT THE CENTRAL PRESSURE HAS REMAINED AROUND
954 MB...BUT THE WINDS HAVE DECREASED AND INITIAL INTENSITY IS NOW
90 KT. THE PLANE REPORTED A SMALL EYE OF 14 N MI DIAMETER.
GIVEN THE CONCENTRIC RING STRUCTURE OBSERVED ON MICROWAVE AND THE
DOUBLE WIND MAXIMA PROVIDED BY THE PLANE...IT IS LIKELY THAT THE
HURRICANE IS GOING THROUGH AN EYEWALL REPLACEMENT AND THE REASON
FOR THE CURRENT WEAKENING. THERE IS AN OPPORTUNITY FOR BILL TO
REGAIN SOME STRENGTH DURING THE NEXT 12 TO 24 HOURS WHILE THE SHEAR
IS LOW AND BEFORE THE HURRICANE REACHES COOLER WATERS.
THEREAFTER...A STEADY WEAKENING IS INDICATED AND BY 72 HOURS...BILL
SHOULD ALREADY BE AN EXTRATROPICAL CYCLONE INTERACTING WITH THE
HIGH LATITUDE WESTERLIES.

BILL IS NOW MOVING TOWARD THE NORTH-NORTHWEST OR 340 DEGREES AT 17
KNOTS. THE HURRICANE SHOULD GRADUALLY TURN MORE TO THE NORTH AROUND
THE BERMUDA-AZORES HIGH TONIGHT AND SATURDAY AND SHOULD BE FORCED TO
RECURVE AS A LARGE MID-LATITUDE TROUGH MOVES EASTWARD ACROSS THE
EASTERN UNITED STATES. THERE HAS NOT BEEN ANY CHANGE IN TRACK
GUIDANCE WHICH IN FACT CONTINUES TO BE TIGHTLY PACKED...MAINTAINING
HIGH CONFIDENCE IN THE TRACK FORECAST.

LARGE SWELLS GENERATED BY THIS HURRICANE WILL AFFECT A LARGE PORTION
OF THE WESTERN NORTH ATLANTIC COASTAL AREA DURING THE NEXT FEW
DAYS. THESE SWELLS WILL LIKELY CAUSE EXTREMELY DANGEROUS SURF AND
LIFE-THREATENING RIP CURRENTS. PLEASE CONSULT STATEMENTS ISSUED BY
YOUR LOCAL WEATHER OFFICE AND METEOROLOGICAL SERVICES FOR MORE
DETAILS.

AT THIS TIME...TROPICAL-STORM-FORCE WINDS ARE NOT FORECAST TO REACH
NEW ENGLAND. HOWEVER...A SLIGHT SHIFT OF THE FORECAST TRACK TO THE
LEFT WOULD REQUIRE A TROPICAL STORM WATCH OR WARNING TONIGHT. THE
WIND SPEED PROBABILITY PRODUCT INDICATES THAT THERE IS ROUGHLY A 25
PERCENT CHANCE OF THESE WINDS REACHING EXTREME SOUTHEASTERN NEW
ENGLAND.

FORECAST POSITIONS AND MAX WINDS

INITIAL 21/2100Z 29.4N 66.9W 90 KT
12HR VT 22/0600Z 31.7N 68.0W 100 KT
24HR VT 22/1800Z 35.1N 68.4W 100 KT
36HR VT 23/0600Z 39.0N 67.2W 85 KT
48HR VT 23/1800Z 43.0N 64.0W 75 KT
72HR VT 24/1800Z 49.5N 47.0W 50 KT...EXTRATROPICAL
96HR VT 25/1800Z 54.5N 20.0W 45 KT...EXTRATROPICAL
120HR VT 26/1800Z 60.0N 6.0W 35 KT...EXTRATROPICAL

$$
FORECASTER AVILA

[Derek Ortt]

Kind of excited that this has underwent repeated EWRCs. Similar environmental moisture as Rita with light shear = EWRC

[bzukajo]

So does anyone know if the Cape Cod Atlantic Seashore- National Seashore would be best for watching the waves- SUN morning?
And what time would be best.? I'm hearing Sunday AM--?

I used to live Dennis Port, and loved the surf there compared to other beaches. Especially when a storm was offshore. Access to the shore is very easy and safe there too. For this storm, I think South Truro would be best. It is in the middle of the vertical part of the pan handle and would be directly west of the storm. However access to the shore is a little more tricky. Wellfleet by the Sea would be a good spot I would think.

[KWT]

So in other words there mayt be a larger scale reason why it can't keep just one eyewall Derek?
Very interesting if that is indeed the case.

[HURAKAN]

Right now there is a mission measuring the environment around Bill

[brunota2003]

Kind of excited that this has underwent repeated EWRCs. Similar environmental moisture as Rita with light shear = EWRC

If you think about it though, dry air entrainment (since there is/was a lot of dry air to its south, where the majority of it's inflow was coming from) causes a weakening of the inner core, which can cause a secondary eyewall to form (maybe similar to what was attempted during Stormfury?). All the while, light shear will not disrupt the secondary eyewall as it is forming. In a sheared environment, wouldn't the secondary eyewall, as it tried to form, act as a "buffer" for the main eyewall, thus never starting the replacement cycle, because it cannot get a grip on the storm as easily?

Just some random person rambling

[wxman57]

So in other words there mayt be a larger scale reason why it can't keep just one eyewall Derek?
Very interesting if that is indeed the case.

Eyewall replacement cycles are very common in stronger hurricanes. Often occurring every 24-36 hours.

[Derek Ortt]

So in other words there mayt be a larger scale reason why it can't keep just one eyewall Derek?
Very interesting if that is indeed the case.

yes, I believe it is environmental and related to the moisture distribution

the dry air in low shear cases likely does not penetrate the core (at least that's my hypothesis). Instea,d it confined the rainbands into the circular pattern. If we have circularity > .5 that persists, then EWRC is likely (circularity is defined as fraction of rain-rate at a given radius > 12.5 mm/h or 37.1 DBZ)

[magnusson_r]

Reply to X-Y-No:

1) Nova Scotia may be in the cone, but I am talking about the predicted path (you know, the one posted at the top of this page) which has it staying *well* offshore (at least 150km offshore);

2) I don't see any forecasts suggesting Bill will strengthen over the next 48 hours, but rather the opposite is more likely to occur. As it encounters the much cooler waters off the Canadian coast it will lose strength very quickly.

[brunota2003]

Reply to X-Y-No:

1) Nova Scotia may be in the cone, but I am talking about the predicted path (you know, the one posted at the top of this page) which has it staying *well* offshore (at least 150km offshore);

2) I don't see any forecasts suggesting Bill will strengthen over the next 48 hours, but rather the opposite is more likely to occur. As it encounters the much cooler waters off the Canadian coast it will lose strength very quickly.

DO NOT FOLLOW THE SKINNY BLACK LINE...it is the reason why the NHC took it off the map. Hurricanes are not a point, nor will they follow the "line". It could hit ANYWHERE within the cone or just outside of it.

viewtopic.php?f=31&t=106179

Look at this:

AT THIS TIME...TROPICAL-STORM-FORCE WINDS ARE NOT FORECAST TO REACH
NEW ENGLAND. HOWEVER...A SLIGHT SHIFT OF THE FORECAST TRACK TO THE
LEFT WOULD REQUIRE A TROPICAL STORM WATCH OR WARNING TONIGHT. THE
WIND SPEED PROBABILITY PRODUCT INDICATES THAT THERE IS ROUGHLY A 25
PERCENT CHANCE OF THESE WINDS REACHING EXTREME SOUTHEASTERN NEW
ENGLAND.

And yet, New England is no where even in the cone!

[x-y-no]

Reply to X-Y-No:

1) Nova Scotia may be in the cone, but I am talking about the predicted path (you know, the one posted at the top of this page) which has it staying *well* offshore (at least 150km offshore);

But the forecast points are not the "predicted path." The predicted path is the cone. The NHC, as well as every other forecast agency of any repute, are very clear on that point.

2) I don't see any forecasts suggesting Bill will strengthen over the next 48 hours, but rather the opposite is more likely to occur. As it encounters the much cooler waters off the Canadian coast it will lose strength very quickly.

Actually, both the official NHC forecast as well as some others do talk about some potential strengthening over the next 12 to 24 hours. None of then (that I am aware of) say anything about Bill "falling apart" as you claimed. Nor is the forecast for Bill to be at less than hurricane strength in the vicinity of Nova Scotia, as you claimed.

[Dionne]

You would be surprised how many people on the North Atlantic coast are following "THE SKINNY BLACK LINE"......my boss is one of them. Now we're hearing about a stalled frontal boundary (from TWC) interacting with Bill?

[massweathernet]

Now we're hearing about a stalled frontal boundary (from TWC) interacting with Bill?

Yes. Go on...

[kat61]

what would a stall mean at this point? can it change the path significantly?
any pro-met have an idea?

[wxman57]

Tropical storm force winds extend well outside the cone. This was the same with Ike. 36 hours before landfall, even the projected hurricane force winds extended east of the cone at landfall. The cone is not a container of a hurricane's effects, it's just a 5-year 67% average that the center will track within the cone.

[WeatherLovingDoc]

Hurricane Bill isn't stalling. As I understand it, a strong mid-western approaching cold front will continue to push closer to the upper east coast tonight. Hurricane Bill's approach may slow and ultimately stall the cold front over the eastern region for a time, allowing numerous showers and thunderstorms to affect areas. Just an amateur's two cents.

[Derek Ortt]

Reply to X-Y-No:

1) Nova Scotia may be in the cone, but I am talking about the predicted path (you know, the one posted at the top of this page) which has it staying *well* offshore (at least 150km offshore);

2) I don't see any forecasts suggesting Bill will strengthen over the next 48 hours, but rather the opposite is more likely to occur. As it encounters the much cooler waters off the Canadian coast it will lose strength very quickly.

I highly doubt this loses much intensity over the cooler waters. There may be enough QG forcing to keep this intense. It will be downstream of an upper trough. This favors surface low development/intensification

[kat61]

Hurricane Bill isn't stalling. As I understand it, a strong mid-western approaching cold front will continue to push closer to the upper east coast tonight. Hurricane Bill's approach may slow and ultimately stall the cold front over the eastern region for a time, allowing numerous showers and thunderstorms to affect areas.

So bill could slow down because he's stalling the front, not the front stalling bill? sorry for
my lack of scientific knowledge.......I'm a newbie and have learned so much listening to you all
for 5 yrs.......S2K 5 yr. stalker!

[pojo]

Here's something a little interesting that I just recieved.

8918kHz USB 2327UTC: TEAL 73 (WC-130J/53rd WRS, Keesler AFB, Ms.) wkg New York Radio with an unreadable position report passed.

Flight in a fl block of 240-300.

NOTE: TEAL 73 is on a reconnaissance flight into Hurricane Bill.

It should have been FL230B240 on route to Bill. Not FL240B300. We commonly sit at 23,600 (400mb) in route to keep the plane calibrated. Once in the storm we tend to sit at 10,000ft (700mb). If they are doing a synoptic mission then they are either at FL230B240 or FL300B310 (30,100ft is 300mb).

Once they are over international waters, we talk on HF radio because the VHF transmitters cannot reach that far.

[WeatherLovingDoc]

Better let the Weather experts answer this, less I post anything incorrect. My impression is that Bill's effect may be to stall the cold front coming in to the East from the mid West, resulting in storms and rain. I don't believe the cold front has any effect on Bill. Best to you. WLD.