Tropical Storm Danny #4

000
WTNT35 KNHC 282108
TCPAT5
BULLETIN
TROPICAL STORM DANNY ADVISORY NUMBER 10...CORRECTED
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL052009
500 PM EDT FRI AUG 28 2009

CORRECTED TO REMOVE ADDITIONAL WATCHES STATEMENT IN SECOND PARAGRAPH

...HURRICANE HUNTERS FIND DANNY STILL A TROPICAL STORM...BEGINNING
TO MOVE NORTHWARD...

A TROPICAL STORM WATCH IS IN EFFECT FOR THE NORTH CAROLINA COAST
FROM CAPE LOOKOUT NORTHWARD TO DUCK...INCLUDING THE PAMLICO AND
ALBEMARLE SOUNDS. A TROPICAL STORM WATCH MEANS THAT TROPICAL STORM
CONDITIONS ARE POSSIBLE WITHIN THE WATCH AREA...IN THIS CASE...
WITHIN 24 HOURS. A TROPICAL STORM WARNING MAY BE REQUIRED FOR
PORTIONS OF THIS AREA TONIGHT.

INTERESTS ELSEWHERE FROM THE CAROLINAS NORTHWARD TO NEW ENGLAND AND
THE CANADIAN MARITIMES SHOULD MONITOR THE PROGRESS OF DANNY.

FOR STORM INFORMATION SPECIFIC TO YOUR AREA IN THE UNITED
STATES...INCLUDING POSSIBLE INLAND WATCHES AND WARNINGS...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 EDT...2100 UTC...THE CENTER OF TROPICAL STORM DANNY WAS
LOCATED NEAR LATITUDE 30.4 NORTH...LONGITUDE 75.4 WEST OR ABOUT 330
MILES...535 KM...SOUTH OF CAPE HATTERAS NORTH CAROLINA AND ABOUT 810
MILES...1300 KM...SOUTH-SOUTHWEST OF NANTUCKET MASSACHUSETTS.

DANNY IS MOVING TOWARD THE NORTH NEAR 6 MPH...9 KM/HR. AN INCREASE
IN FORWARD SPEED IS EXPECTED TONIGHT WITH A TURN TOWARD THE
NORTH-NORTHEAST EXPECTED ON SUNDAY. ON THIS TRACK...THE CENTER OF
DANNY IS EXPECTED TO PASS OFFSHORE OF THE OUTER BANKS OF NORTH
CAROLINA EARLY SATURDAY...PASS OFFSHORE OF SOUTHEASTERN NEW ENGLAND
ON SATURDAY NIGHT AND MOVE NEAR THE CANADIAN MARITIMES SUNDAY.

DATA FROM THE AIR FORCE RESERVE RECONNAISSANCE HURRICANE HUNTER
AIRCRAFT INDICATE THAT MAXIMUM SUSTAINED WINDS ARE NEAR 40 MPH...65
KM/HR...WITH HIGHER GUSTS. SOME SLIGHT STRENGTHENING IS POSSIBLE
TONIGHT...WITH LITTLE CHANGE IN INTENSITY EXPECTED ON SATURDAY.
DANNY IS EXPECTED TO BECOME EXTRATROPICAL ON SATURDAY NIGHT.

TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 175 MILES...280 KM
MOSTLY TO THE SOUTHEAST OF THE CENTER.

DATA FROM THE HURRICANE HUNTER AIRCRAFT INDICATE THAT THE MINIMUM
CENTRAL PRESSURE IS 1007 MB...29.74 INCHES.

LARGE SWELLS FROM DANNY ARE EXPECTED TO PRODUCE DANGEROUS SURF
CONDITIONS AND LIFE-THREATENING RIP CURRENTS ALONG THE U.S. EAST
COAST DURING THE NEXT DAY OR TWO. PLEASE CONSULT STATEMENTS ISSUED
BY YOUR LOCAL NATIONAL WEATHER SERVICE FORECAST OFFICE FOR MORE
DETAILS.

...SUMMARY OF 500 PM EDT INFORMATION...
LOCATION...30.4N 75.4W
MAXIMUM SUSTAINED WINDS...40 MPH
PRESENT MOVEMENT...NORTH OR 360 DEGREES AT 6 MPH
MINIMUM CENTRAL PRESSURE...1007 MB

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

$$
FORECASTER BRENNAN

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000
WTNT45 KNHC 282035
TCDAT5
TROPICAL STORM DANNY DISCUSSION NUMBER 10
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL052009
500 PM EDT FRI AUG 28 2009

AFTER STALLING EARLIER THIS AFTERNOON...THE CENTER OF DANNY IS
FINALLY MOVING SLOWLY NORTHWARD OR NORTH-NORTHEASTWARD. DATA FROM AN
AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT SUGGEST THAT DANNY IS
STILL A MINIMAL TROPICAL STORM...BASED ON A 33-KT OBSERVATION FROM
THE SFMR IN THE SOUTHEASTERN QUADRANT.

THE INTENSITY FORECAST SHOWS THE POSSIBILITY FOR A LITTLE
STRENGTHENING IN THE SHORT TERM...AS THE INCREASING UPPER-LEVEL
DIVERGENCE COULD SUPPORT THE REDEVELOPMENT OF CONVECTION NEAR THE
CENTER. HOWEVER...BY 24 HOURS...DANNY WILL BE MOVING INTO A VERY
UNFAVORABLE ENVIRONMENT FOR A TROPICAL CYCLONE...WITH THE SHIPS
MODEL SHOWING WIND SHEAR INCREASING TO 35 KT BY THAT TIME. BY 36
HOURS...DANNY WILL BE OVER SSTS OF NEAR 20C...AND INTERACTING WITH
THE DEEP-LAYER BAROCLINIC TROUGH OVER THE EASTERN U.S. MOST OF
THE LATEST GLOBAL MODELS AND PHASE SPACE DIAGRAMS SHOW THAT DANNY
WILL BE EXTRATROPICAL BY THAT TIME. THERE IS THE POTENTIAL FOR SOME
INTENSIFICATION OF DANNY LATE IN THE FORECAST PERIOD AS AN
EXTRATROPICAL CYCLONE OVER THE NORTH ATLANTIC.

THE GUIDANCE WAS INITIALIZED WITH A LONG TERM MOTION OF 315/08...
AND REMAINS IS GOOD AGREEMENT ON THE RAPID ACCELERATION OF DANNY
NORTHWARD AND NORTH-NORTHEASTWARD. IN FACT...THE MODEL SPREAD IS
SMALLER NOW THAN IT WAS EARLIER TODAY. THE OFFICIAL TRACK IS SLOWER
THAN THE MODEL CONSENSUS THROUGH MOST OF THE PERIOD DUE TO THE SLOW
INITIAL MOTION. FROM 24 TO 36 HOURS...THE NEW FORECAST IS SHIFTED
TO THE RIGHT OF THE PREVIOUS FORECAST TRACK...BUT DANNY IS STILL
EXPECTED TO MOVE CLOSE TO THE SOUTHEASTERN COAST OF NEW ENGLAND AND
APPROACH NOVA SCOTIA IN 36-48 HOURS.

DATA FROM THE AIRCRAFT SUGGEST THAT THE ONLY 34-KT WINDS ARE LOCATED
IN THE SOUTHEASTERN QUADRANT. THE LACK OF WINDS ON THE WEST SIDE OF
DANNY LESSEN THE THREAT FOR TROPICAL STORM WIND REACHING THE NORTH
CAROLINA OUTER BANKS. HOWEVER...THE WATCH IS LEFT IN PLACE IN CASE
THE WIND FIELD BECOMES BETTER DEFINED ON THE WESTERN SIDE OF DANNY.
AS DANNY BECOMES EXTRATROPICAL...ITS EXPANDING WIND FIELD MAY
IMPACT THE COAST OF NEW ENGLAND. THESE POTENTIAL IMPACTS WILL BE
HANDLED WITH GALE WARNINGS AND OTHER PRODUCTS ISSUED BY LOCAL NWS
OFFICES IN THAT REGION.



FORECAST POSITIONS AND MAX WINDS

INITIAL 28/2100Z 30.4N 75.4W 35 KT
12HR VT 29/0600Z 32.7N 75.8W 40 KT
24HR VT 29/1800Z 37.3N 73.2W 40 KT
36HR VT 30/0600Z 41.9N 68.2W 40 KT...EXTRATROPICAL
48HR VT 30/1800Z 46.5N 61.4W 40 KT...EXTRATROPICAL
72HR VT 31/1800Z 50.5N 49.5W 40 KT...EXTRATROPICAL
96HR VT 01/1800Z 53.0N 35.0W 45 KT...EXTRATROPICAL
120HR VT 02/1800Z 55.0N 22.0W 50 KT...EXTRATROPICAL

$$
FORECASTER BRENNAN

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WOCN31 CWHX 281800
Tropical storm Danny information statement issued by the
Canadian hurricane centre of Environment Canada at 3.00 PM ADT
Friday 28 August 2009.

The next statement will be issued by 9.00 PM ADT

...Danny bringing rain to Atlantic Canada...

1. Current position, strength, central pressure and motion

At 3.00 PM ADT... Tropical storm Danny was located near
Latitude 30.1 north...Longitude 75.7 west or about 355 miles...570
Km...South of Cape Hatteras. Maximum sustained winds are
Estimated at 35 knots... 74 km/h... And central pressure at 1007
MB. Danny is currently stationary.

2. Forecast position, central pressure and strength

Date time lat lon MSLP Max wind
ADT MB kts kmh
Aug 28 3.00 PM 30.1N 75.7W 1007 35 65
Aug 29 3.00 AM 35.1N 74.8W 1004 40 74
Aug 29 3.00 PM 39.3N 72.1W 1001 40 74
Aug 30 3.00 AM 43.1N 67.6W 1002 40 74 transitioning
Aug 30 3.00 PM 45.5N 62.9W 1002 40 74 transitioning
Aug 31 3.00 AM 47.8N 57.5W 1002 40 74 post-tropical
Aug 31 3.00 PM 49.8N 51.9W 1003 40 74 post-tropical
Sep 01 3.00 AM 51.4N 44.3W 1003 40 74 post-tropical

3. Public weather impacts and warnings summary
Rain should move into the Maritimes later on Saturday and
Pull out Sunday afternoon. Model guidance shows amounts
Of near 70 mm possible for Southwest Nova Scotia and southern
New Brunswick...With amounts of 90 or higher possible locally.
Rainfall warnings will likely be issued by 5 AM Saturday for parts of
Nova Scotia and Southern New Brunswick..And possibly for
Prince Edward Island. Currently wind warnings are not expected.
However the highest winds will be expected south of the storm track.
Heavy swell associated with the storm may cause significant surf
And rip tides along the Atlantic coast of Nova Scotia. Caution
Should be observed by people near the coast.

The rain will move into Southwestern Newfoundland on Sunday. Rainfall
amounts may reach or exceed 50 mm locally. Warnings may be issued as
appropriate Saturday or later.

4. Marine weather impacts and warnings summary
Danny will weaken as it moves through canadian waters.
It has now become less likely that storm force winds will occur
Upon entering the marine district. The winds will diminish as it
continues to move over colder waters. Gale warnings have been
Posted for western Maritimes waters and may be extended to
Eastern maritime waters tonight. If necessary warnings should be
issued overnight tonight or later for Newfoundland waters.

5. Technical discussion for meteorologists

A. Analysis
From the visible satellite images today Danny is almost
Completely isolated from the convection..Which is east of the
Surface circulation. Current observations barely support 35
Kts..Assuming higher winds in the eastern sector. A hurricane
Hunter aircraft is currently in the area.

There is also a chance of slight intensification if convection
develops over the surface circulation. Currently convection has
intensified southeast of the low centre. There is also the chance
that a new circulation centre will develop today eastward in the
strong convective region.

B. Prognostic
Our track agrees with nhc...Which is similar to our previous track.
Model guidance continues to suggest Danny will move along the
Spine of Nova Scotia and then eastwards across Central Newfoundland.
Most of the dynamical models bring it in somewhere near Yarmouth..
With the avn an outlier to the north through Southern New Brunswick.
There is still some potential for some re-strengthening as Danny
Moves through weakening shear...With wind strength forecast to be
40 knots as it passes to the east of Cape Hatteras today.
After that Danny will come under the influence of an upper trough
digging over the central us which will steer it in a northeasterly
Direction. Increasing shear..Combined with Danny moving over colder
Waters as it goes north of Cape Hatteras..Should weaken the storm.
Currently the guidance keeps it below hurricane strength with most
Of the models showing about 40 to 45 knots over the Scotian shelf.


C. Public weather
Decaying tropical systems often produce heavy rain over the
Maritimes and past experience indicates that locally higher
Amounts may be produced. Dynamic models are producing the
Expected qpfs of 50 to 100 mm with the location of the maxima
Varying from model to model. The Gem and gfs show possible
Maxima to the left of track into Southern New Brunswick...And both
show a possible maximum over Southwestern Nova Scotia. Danny will
Be monitored very closely..Especially due to the high uncertainty
In its development at this time.

D. Marine weather
Wind radii are initialised consistent with quikscat data and nhc
guidance. Last nights quikscat pass only captured the outer edges
Of the wind field...And modelled thereafter for a somewhat weakened
system. Storm surge should not be an issue due to neap tides this
weekend and insufficient winds. Waves should be less than 8 metres
offshore of Nova Scotia and less than 6 into Newfoundland waters.
Coastal waves should be of order 5 metres or less.

Predicted wind radii (NM)
Time gales storms hurricane
Ne se sw nw ne se sw nw ne se sw nw
28/18Z 150 120 0 30 0 0 0 0 0 0 0 0
29/06Z 150 120 0 40 0 0 0 0 0 0 0 0
29/18Z 150 110 30 45 0 0 0 0 0 0 0 0
30/06Z 175 150 85 75 0 0 0 0 0 0 0 0
30/18Z 210 220 140 120 0 0 0 0 0 0 0 0
31/06Z 230 270 160 140 0 0 0 0 0 0 0 0
31/18Z 240 300 180 150 0 0 0 0 0 0 0 0
01/06Z 240 300 180 150 0 0 0 0 0 0 0 0


End hatt/mercer