T Storm Helene Advisories=Last Advisory Written by NHC

[senorpepr]

WTNT33 KNHC 180849
TCPAT3
BULLETIN
HURRICANE HELENE ADVISORY NUMBER 24
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL082006
500 AM AST MON SEP 18 2006

...HELENE A LITTLE STRONGER AS IT JOGS NORTH-NORTHWESTWARD...

AT 500 AM AST...0900Z...THE CENTER OF HURRICANE HELENE WAS LOCATED
NEAR LATITUDE 22.3 NORTH...LONGITUDE 49.6 WEST OR ABOUT 920 MILES...
1480 KM...EAST-NORTHEAST OF THE NORTHERN LEEWARD ISLANDS AND ABOUT
1160 MILES...1865 KM...EAST-SOUTHEAST OF BERMUDA.

HELENE IS MOVING TOWARD THE NORTH-NORTHWEST NEAR 7 MPH...11 KM/HR.
A TURN TO THE WEST-NORTHWEST IS EXPECTED OVER THE NEXT 24 HOURS.

MAXIMUM SUSTAINED WINDS ARE NEAR 120 MPH...195 KM/HR...WITH HIGHER
GUSTS. HELENE IS A CATEGORY THREE HURRICANE ON THE SAFFIR-SIMPSON
HURRICANE SCALE. SOME ADDITIONAL STRENGTHENING IS FORECAST DURING
THE NEXT 24 HOURS.

HURRICANE FORCE WINDS EXTEND OUTWARD UP TO 50 MILES...85 KM...FROM
THE CENTER...AND TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 200
MILES...325 KM.

ESTIMATED MINIMUM CENTRAL PRESSURE IS 958 MB...28.29 INCHES.

REPEATING THE 500 AM AST POSITION...22.3 N...49.6 W. MOVEMENT
TOWARD...NORTH-NORTHWEST NEAR 7 MPH. MAXIMUM SUSTAINED WINDS...120
MPH. MINIMUM CENTRAL PRESSURE...958 MB.

THE NEXT ADVISORY WILL BE ISSUED BY THE NATIONAL HURRICANE CENTER AT
1100 AM AST.

$$
FORECASTER FRANKLIN


WTNT43 KNHC 180846
TCDAT3
HURRICANE HELENE DISCUSSION NUMBER 24
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL082006
500 AM EDT MON SEP 18 2006

THE INITIAL MOTION IS 340/6. WATER VAPOR IMAGERY SHOWS A SMALL
MID- TO UPPER-LEVEL LOW LOCATED A FEW HUNDRED MILES TO THE
NORTH-NORTHWEST OF THE HURRICANE...AND THIS UPPER LOW MAY BE
RESPONSIBLE FOR THE MORE NORTHWARD CURRENT MOTION. AS THIS
LOW...ALONG WITH HURRICANE GORDON...LIFT OUT OVER THE NEXT DAY OR
SO...RIDGING SHOULD DEVELOP TO THE NORTH OF HELENE. THIS RIDGING
IS EXPECTED TO FORCE HELENE ON MORE OF A WESTWARD TRACK OVER THE
NEXT DAY OR TWO...ALTHOUGH IT IS WORTH NOTING THAT THE GUIDANCE HAS
HAD A DECIDED SHORT-TERM WESTWARD BIAS OVER THE LAST COUPLE OF
DAYS.

THE LONGER RANGE PROGNOSIS IS LESS CLEAR. A DEEP-LAYER LOW CURRENTLY
EXTENDS SOUTHWARD FROM THE WESTERN ATLANTIC INTO THE BAHAMAS...AND
A SECOND LARGE TROUGH IS MOVING THROUGH THE NORTHERN PLAINS. MODELS
ARE IN GENERAL AGREEMENT ON WEAKENING THE WESTERN ATLANTIC LOW AND
BRINGING THE SECOND TROUGH THROUGH NEW ENGLAND IN 4 TO 5 DAYS...
ALLOWING SOME RIDGING TO DEVELOP IN THE WESTERN ATLANTIC BY DAY 5.
HOWEVER...THE SPECIFIC INTERACTIONS BETWEEN HELENE AND THESE
VARIOUS FEATURES VARY WIDELY AMONG THE MODELS. ON THE RIGHT SIDE OF
THE GUIDANCE SUITE...THE GFDL AND CANADIAN MODELS HAVE HELENE
LIFTED NORTH BY THE WESTERN ATLANTIC LOW JUST ENOUGH TO THEN BE
PICKED UP BY THE PLAINS TROUGH. ON THE LEFT ARE THE UKMET AND
NOGAPS...WHICH KEEP HELENE FARTHER SOUTH INITIALLY AND END UP WITH
IT CAPTURED OR SLOWED BY THE WESTERN ATLANTIC RIDGE ON DAY 5. THE
GFS...WHICH HAD BEEN LEANING LEFT...HAS NOW SHIFTED TO THE CENTER
OF THE GUIDANCE ENVELOPE. THE 00Z RUN OF THE GFS FORECASTS THE
WESTERN ATLANTIC RIDGE TO BE WEAKER AND DISPLACED TO THE SOUTH OF
THE PREVIOUS RUN...AND THIS IS ENOUGH TO RESULT IN A RATHER LARGE
NORTHWARD SHIFT IN THE TRACK OF HELENE IN THE MODEL. CONVERSELY THE
ECMWF...WHICH HAD BEEN SHOWING A RAPID RECURVATURE...HAS SHIFTED
LEFT AND IS NOW PRETTY CLOSE TO THE GFS. THE BOTTOM LINE OF ALL
THIS IS THAT WHAT HAPPENS IN THE NEXT 24 TO 48 HOURS...THAT
IS...HOW MUCH LATITUDE HELENE CAN GAIN...COULD MAKE ALL THE
DIFFERENCE BETWEEN A QUICK RECURVATURE AND AN AGONIZINGLY SLOW PATH
THROUGH THE WESTERN ATLANTIC. THE OFFICIAL FORECAST HAS BEEN
SHIFTED A LITTLE TO THE NORTHEAST OF THE PREVIOUS TRACK...BUT IS
STILL TO THE LEFT OF THE GFS/ECMWF AND THE DYNAMICAL MODEL
CONSENSUS. IT IS PERHAPS OBVIOUS BY NOW THAT I CONSIDER THE TRACK
FORECAST TO HAVE MORE THAN THE NORMAL AMOUNT OF UNCERTAINTY.

EYEWALL CONVECTION IS A LITTLE COLDER AND MORE SYMMETRIC THAN IT WAS
6 HOURS AGO. SUBJECTIVE DVORAK INTENSITY ESTIMATES FROM TAFB AND
SAB ARE 102 KT...WHILE THE CIMSS/ADT ESTIMATES ARE A LITTLE HIGHER
AND HAVE BEEN INCREASING. THE ADVISORY ESTIMATE IS INCREASED TO 105
KT. THE OUTFLOW PATTERN REMAINS VERY STRONG...ALTHOUGH THERE HAS
BEEN SOME FLATTENING ON THE WESTERN SIDE LIKELY ASSOCIATED WITH THE
SMALL UPPER LOW. THIS LOW COMPLICATES THE SHORT-TERM INTENSITY
FORECAST. ALTHOUGH AT THE MOMENT IT MAY BE IMPEDING THE OUTFLOW...
WATER VAPOR IMAGERY SUGGESTS THAT VORTICITY FROM THIS LOW IS BEING
ENTRAINED INTO HELENE...AND THIS KIND OF TROUGH INTERACTION CAN
SOMETIMES PROVIDE A KICK START FOR ADDITIONAL INTENSIFICATION. THE
OFFICIAL FORECAST IS SLIGHTLY ABOVE THE SHIPS AND GFDL GUIDANCE.
ALL INDICATIONS ARE THAT HELENE WILL BE AT OR NEAR MAJOR HURRICANE
STATUS THROUGH THE FORECAST PERIOD.


FORECAST POSITIONS AND MAX WINDS

INITIAL 18/0900Z 22.3N 49.6W 105 KT
12HR VT 18/1800Z 23.1N 50.4W 110 KT
24HR VT 19/0600Z 23.7N 51.7W 115 KT
36HR VT 19/1800Z 24.0N 53.3W 115 KT
48HR VT 20/0600Z 24.3N 55.0W 110 KT
72HR VT 21/0600Z 26.0N 57.5W 105 KT
96HR VT 22/0600Z 28.2N 58.9W 100 KT
120HR VT 23/0600Z 30.0N 60.0W 95 KT

$$
FORECASTER FRANKLIN


WTNT23 KNHC 180846
TCMAT3
HURRICANE HELENE FORECAST/ADVISORY NUMBER 24
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL082006
0900 UTC MON SEP 18 2006

HURRICANE CENTER LOCATED NEAR 22.3N 49.6W AT 18/0900Z
POSITION ACCURATE WITHIN 20 NM

PRESENT MOVEMENT TOWARD THE NORTH-NORTHWEST OR 340 DEGREES AT 6 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 958 MB
MAX SUSTAINED WINDS 105 KT WITH GUSTS TO 130 KT.
64 KT....... 45NE 40SE 30SW 35NW.
50 KT....... 90NE 65SE 45SW 60NW.
34 KT.......175NE 150SE 100SW 125NW.
12 FT SEAS..275NE 200SE 200SW 250NW.
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 22.3N 49.6W AT 18/0900Z
AT 18/0600Z CENTER WAS LOCATED NEAR 22.0N 49.4W

FORECAST VALID 18/1800Z 23.1N 50.4W
MAX WIND 110 KT...GUSTS 135 KT.
64 KT... 45NE 40SE 30SW 35NW.
50 KT... 90NE 65SE 45SW 60NW.
34 KT...175NE 150SE 100SW 125NW.

FORECAST VALID 19/0600Z 23.7N 51.7W
MAX WIND 115 KT...GUSTS 140 KT.
64 KT... 45NE 40SE 30SW 35NW.
50 KT... 90NE 65SE 45SW 60NW.
34 KT...175NE 150SE 100SW 125NW.

FORECAST VALID 19/1800Z 24.0N 53.3W
MAX WIND 115 KT...GUSTS 140 KT.
64 KT... 45NE 40SE 30SW 35NW.
50 KT...100NE 75SE 60SW 75NW.
34 KT...200NE 175SE 125SW 150NW.

FORECAST VALID 20/0600Z 24.3N 55.0W
MAX WIND 110 KT...GUSTS 135 KT.
50 KT...100NE 75SE 60SW 75NW.
34 KT...200NE 175SE 125SW 150NW.

FORECAST VALID 21/0600Z 26.0N 57.5W
MAX WIND 105 KT...GUSTS 130 KT.
50 KT...100NE 75SE 60SW 75NW.
34 KT...200NE 175SE 125SW 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 22/0600Z 28.2N 58.9W
MAX WIND 100 KT...GUSTS 120 KT.

OUTLOOK VALID 23/0600Z 30.0N 60.0W
MAX WIND 95 KT...GUSTS 115 KT.

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 22.3N 49.6W

NEXT ADVISORY AT 18/1500Z

$$
FORECASTER FRANKLIN

[cycloneye]

511
WTNT33 KNHC 181434
TCPAT3
BULLETIN
HURRICANE HELENE ADVISORY NUMBER 25
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL082006
1100 AM AST MON SEP 18 2006

...GORDON FORECAST TO TURN WESTWARD...EXPECTED TO REMAIN OVER OPEN
WATERS...

AT 1100 AM AST...1500Z...THE CENTER OF HURRICANE HELENE WAS LOCATED
NEAR LATITUDE 23.2 NORTH...LONGITUDE 50.2 WEST OR ABOUT 900 MILES...
1450 KM...EAST-NORTHEAST OF THE NORTHERN LEEWARD ISLANDS AND ABOUT
1090 MILES...1755 KM...EAST-SOUTHEAST OF BERMUDA.

HELENE IS MOVING TOWARD THE NORTHWEST NEAR 9 MPH...15 KM/HR. A
GRADUAL TURN TO THE WEST IS EXPECTED DURING THE NEXT DAY OR SO.

MAXIMUM SUSTAINED WINDS HAVE INCREASED TO NEAR 125 MPH...205
KM/HR...WITH HIGHER GUSTS. NO SIGNIFICANT CHANGE IN STRENGTH IS
FORECAST DURING THE NEXT 24 HOURS.

HURRICANE FORCE WINDS EXTEND OUTWARD UP TO 50 MILES...85 KM...FROM
THE CENTER...AND TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 200
MILES...325 KM.

ESTIMATED MINIMUM CENTRAL PRESSURE IS 954 MB...28.17 INCHES.

REPEATING THE 1100 AM AST POSITION...23.2 N...50.2 W. MOVEMENT
TOWARD...NORTHWEST NEAR 9 MPH. MAXIMUM SUSTAINED WINDS...125 MPH.
MINIMUM CENTRAL PRESSURE...954 MB.

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

$$

FORECASTER AVILA

049
WTNT43 KNHC 181435
TCDAT3
HURRICANE HELENE DISCUSSION NUMBER 25
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL082006
1100 AM EDT MON SEP 18 2006

HELENE AND GORDON WERE BASICALLY AT THE SAME LONGITUDE THIS MORNING
AND THERE WAS A WEAKENING ON THE RIDGE NORTH OF HELENE. THIS
RESULTED IN HELENE MOVING IN A NORTH-NORTHWESTWARD TRACK FOR THE
PAST SEVERAL HOURS. HOWEVER...IT APPEARS THAT THE HURRICANE IS
READY TO BEGIN THE WESTWARD TURN ANTICIPATED BY THE GLOBAL MODELS.
IN FACT...HELENE HAS ALREADY TURNED A LITTLE BIT AND IS NOW MOVING
TOWARD THE NORTHWEST OR 310 DEGREES AT 8 KNOTS. THE TROUGH
CURRENTLY LOCATED OVER THE WESTERN ATLANTIC IS FORECAST TO WEAKEN
WHILE A RIDGE TO THE NORTH OF HELENE IS EXPECTED TO AMPLIFY. THIS
PATTERN WOULD TEMPORARILY STEER HELENE ON A WESTWARD TRACK FOR A
COUPLE OF DAYS. THEREAFTER...GLOBAL MODELS SHOW ANOTHER LARGE
TROUGH APPROACHING THE EASTERN UNITED STATES. THIS TROUGH WILL
FORCE HELENE SLOWLY NORTHWARD. ALTHOUGH...THE CONFIDENCE IS QUITE
HIGH THAT HELENE WILL EVENTUALLY TURN NORTHWARD...IT IS VERY
DIFFICULT TO FORECAST THE LONGITUDE THIS WILL OCCUR. THERE ARE SOME
INDICATIONS FROM THE LAST RUN OF THE GLOBAL MODELS THAT BY DAYS 4
AND 5...THE STEERING CURRENTS WILL WEAKEN AND HELENE WILL BE MOVING
VERY SLOWLY.

THERE HAS NO SIGNIFICANT CHANGE IN THE CLOUD PATTERN...JUST A SMALL
INCREASE IN THE DVORAK T-NUMBERS. THEREFORE...THE INTENSITY HAS
BEEN ADJUSTED UPWARD TO 110 KNOTS. A NOAA P3 PLANE AND NOAA G4
JET...CURRENTLY ON A RESEARCH MISSION IN THE AREA WILL BE PROVIDING
VALUABLE DATA THIS AFTERNOON AND WE COULD HAVE A BETTER ESTIMATE OF
THE STRUCTURE OF THE HURRICANE AND THE STEERING. HELENE COULD
STRENGTHEN JUST LITTLE BIT MORE SINCE THE SHEAR IS LOW AND THE
OCEAN IS WARM. HOWEVER...MOST OF THE INTENSITY GUIDANCE FORECAST
LITTLE CHANGE OR GRADUAL WEAKENING.


FORECAST POSITIONS AND MAX WINDS

INITIAL 18/1500Z 23.2N 50.2W 110 KT
12HR VT 19/0000Z 23.9N 51.0W 110 KT
24HR VT 19/1200Z 24.3N 52.8W 115 KT
36HR VT 20/0000Z 24.3N 54.5W 115 KT
48HR VT 20/1200Z 24.5N 56.0W 110 KT
72HR VT 21/1200Z 27.0N 58.0W 105 KT
96HR VT 22/1200Z 29.5N 59.5W 100 KT
120HR VT 23/1200Z 31.5N 60.5W 95 KT

$$
FORECASTER AVILA

[Josephine96]

I'm assuming the advisory is going to be reissued if it says "Gordon expected to turn westward" lol

[mtm4319]

[cycloneye]

010
WTNT33 KNHC 182033
TCPAT3
BULLETIN
HURRICANE HELENE ADVISORY NUMBER 26
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL082006
500 PM AST MON SEP 18 2006

...HELENE REMAINS LARGE AND POWERFUL...FORECAST TO REMAIN OUT TO
SEA...

AT 500 PM AST...2100Z...THE CENTER OF HURRICANE HELENE WAS LOCATED
NEAR LATITUDE 23.9 NORTH...LONGITUDE 51.1 WEST OR ABOUT 870 MILES...
1395 KM...EAST-NORTHEAST OF THE NORTHERN LEEWARD ISLANDS AND ABOUT
1015 MILES...1635 KM...EAST-SOUTHEAST OF BERMUDA.

HELENE IS MOVING TOWARD THE WEST-NORTHWEST NEAR 9 MPH...15 KM/HR...
AND THIS GENERAL MOTION IS EXPECTED TO CONTINUE THROUGH TUESDAY.

MAXIMUM SUSTAINED WINDS ARE NEAR 115 MPH...185 KM/HR...WITH HIGHER
GUSTS. HELENE REMAINS A CATEGORY THREE HURRICANE ON THE
SAFFIR-SIMPSON HURRICANE SCALE. NO SIGNIFICANT CHANGE IN STRENGTH
IS FORECAST DURING THE NEXT 24 HOURS.

HURRICANE FORCE WINDS EXTEND OUTWARD UP TO 70 MILES...110 KM...FROM
THE CENTER...AND TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 200
MILES...325 KM.

ESTIMATED MINIMUM CENTRAL PRESSURE IS 960 MB...28.35 INCHES.

REPEATING THE 500 PM AST POSITION...23.9 N...51.1 W. MOVEMENT
TOWARD...WEST-NORTHWEST NEAR 9 MPH. MAXIMUM SUSTAINED WINDS...115
MPH. MINIMUM CENTRAL PRESSURE...960 MB.

THE NEXT ADVISORY WILL BE ISSUED BY THE NATIONAL HURRICANE CENTER AT
1100 PM AST.

$$
FORECASTER AVILA

[cycloneye]

WTNT43 KNHC 182035
TCDAT3
HURRICANE HELENE DISCUSSION NUMBER 26
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL082006
500 PM EDT MON SEP 18 2006

A NOAA RESEARCH AIRCRAFT MADE A PASS THROUGH THE CENTER OF HELENE
EARLIER TODAY AND FOUND THAT THE HURRICANE WAS NOT AS STRONG AS
PREVIOUSLY ESTIMATED BY SATELLITE. THEY MEASURED A MINIMUM PRESSURE
OF 966 MB AND SEVERAL MILLIBARS LOWER TWO HOURS LATER. MAXIMUM
WINDS REPORTED FROM THE SFMR INSTRUMENT ONBOARD THE PLANE WERE ONLY
79 KNOTS. HOWEVER...THE SATELLITE PRESENTATION STILL SUPPORTS WINDS
STRONGER THAN 100 KNOTS. AT THIS TIME...I AM ASSUMING THAT THE NOAA
PLANE DID NOT SAMPLE THE ENTIRE CIRCULATION AND THE INITIAL
INTENSITY IS ADJUSTED TO 100 KNOTS. IF THE SATELLITE PRESENTATION
DETERIORATES LATER TODAY OR TONIGHT...WINDS COULD BE ADJUSTED
DOWNWARD. HELENE COULD STRENGTHEN A LITTLE DURING THE NEXT DAY OR
SO SINCE THE SHEAR IS FORECAST TO BE LOW AND THE OCEAN IS WARM.
MOST OF THE INTENSITY GUIDANCE SHOWS NO SIGNIFICANT CHANGE IN
STRENGTH DURING THE NEXT DAY OR TWO.

HELENE IS NOW MOVING TOWARD THE WEST-NORTHWEST OR 300 DEGREES AT 8
KNOTS. THE SUBTROPICAL RIDGE NORTH OF HELENE IS FORECAST TO EXPAND
WESTWARD DURING THE NEXT DAY OR TWO. THIS PATTERN WOULD TEMPORARILY
STEER HELENE TOWARD THE WEST. HOWEVER...BEYOND TWO DAYS A LARGE
TROUGH IS FORECAST TO DEVELOP OVER THE WESTERN ATLANTIC...FORCING
HELENE TO TURN NORTHWARD AND NORTHEASTWARD WITH INCREASING FORWARD
SPEED. I AM MUCH MORE CONFIDENT IN THIS TRACK FORECAST SINCE ALL
THE GLOBAL MODELS ARE NOW IN GOOD AGREEMENT...AND THEIR SOLUTION
BECAME CLOSER TO THE GFDL...WHICH HAS BEEN STUBBORNLY TURNING HELENE
NORTHWARD ALL ALONG. DUE TO THE EASTWARD CHANGE IN THE GLOBAL
MODELS IN THE LATEST RUN...THE OFFICIAL FORECAST HAS BEEN SHIFTED A
LITTLE BIT EASTWARD AND IS NOW SHOWING RECURVATURE EAST OF 60W
LONGITUDE.

FORECAST POSITIONS AND MAX WINDS

INITIAL 18/2100Z 23.9N 51.1W 100 KT
12HR VT 19/0600Z 24.6N 52.2W 100 KT
24HR VT 19/1800Z 24.7N 54.0W 105 KT
36HR VT 20/0600Z 24.8N 56.5W 105 KT
48HR VT 20/1800Z 26.0N 57.0W 105 KT
72HR VT 21/1800Z 29.5N 58.5W 100 KT
96HR VT 22/1800Z 33.0N 57.5W 90 KT
120HR VT 23/1800Z 40.0N 50.0W 80 KT

$$
FORECASTER AVILA

[cycloneye]

625
WTNT33 KNHC 190228
TCPAT3
BULLETIN
HURRICANE HELENE ADVISORY NUMBER 27
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL082006
1100 PM AST MON SEP 18 2006

...LARGE AND POWERFUL HURRICANE HELENE EXPECTED TO REMAIN OUT AT
SEA...

AT 1100 PM AST...0300Z...THE CENTER OF HURRICANE HELENE WAS LOCATED
NEAR LATITUDE 24.2 NORTH...LONGITUDE 51.4 WEST OR ABOUT 990 MILES...
1590 KM...EAST-SOUTHEAST OF BERMUDA.

HELENE IS MOVING TOWARD THE WEST-NORTHWEST NEAR 8 MPH...13 KM/HR...
AND THIS MOTION IS EXPECTED TO

MAXIMUM SUSTAINED WINDS ARE NEAR 115 MPH...185 KM/HR...WITH HIGHER
GUSTS. CONDITIONS APPEAR FAVORABLE FOR STRENGTHENING DURING THE
NEXT 24 HOURS.

HELENE IS A LARGE HURRICANE. HURRICANE FORCE WINDS EXTEND OUTWARD
UP TO 70 MILES...110 KM...FROM THE CENTER...AND TROPICAL STORM
FORCE WINDS EXTEND OUTWARD UP TO 230 MILES...370 KM.

ESTIMATED MINIMUM CENTRAL PRESSURE IS 960 MB...28.35 INCHES.
REPEATING THE 1100 PM AST POSITION...24.2 N...51.4 W. MOVEMENT
TOWARD...WEST-NORTHWEST NEAR 8 MPH. MAXIMUM SUSTAINED WINDS...115
MPH. MINIMUM CENTRAL PRESSURE...960 MB.

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

$$
FORECASTER PASCH

[cycloneye]

241
WTNT43 KNHC 190228
TCDAT3
HURRICANE HELENE DISCUSSION NUMBER 27
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL082006
1100 PM EDT MON SEP 18 2006

ALTHOUGH THE CLOUD PATTERN OF HELENE IS SLIGHTLY ELONGATED TO THE
NORTH...THE SATELLITE PRESENTATION OF THE CORE OF THE HURRICANE HAS
BECOME MORE IMPRESSIVE OVER THE PAST FEW HOURS. CENTRAL CONVECTION
IS COOLING AND THE EYE IS BECOMING BETTER DEFINED. CIRRUS OUTFLOW
IS RATHER SYMMETRICAL AND EXPANDING. DVORAK T-NUMBERS OF 5.5 FROM
ALL AGENCIES SUPPORT KEEPING THE INTENSITY AT 100 KT AT THIS TIME.
THE HURRICANE WILL CONTINUE TO MOVE OVER WARM OCEAN WATERS AND THE
VERTICAL SHEAR IS EXPECTED TO REMAIN WEAK OVER THE NEXT COUPLE OF
DAYS. STRENGTHENING IS LIKELY AND THE OFFICIAL WIND SPEED FORECAST
IS SLIGHTLY HIGHER THAN THE SHIPS...GFDL...AND FSU SUPERENSEMBLE
INTENSITY GUIDANCE. INDEED...GIVEN THE INCREASING ORGANIZATION OF
THE INNER CORE...THIS INTENSITY FORECAST COULD BE CONSERVATIVE...
AND HELENE CERTAINLY HAS THE POTENTIAL TO BECOME A CATEGORY 4
HURRICANE.

HELENE IS MOVING SLOWLY WEST-NORTHWESTWARD...300/7. A MORE WESTWARD
COMPONENT OF MOTION IS EXPECTED DURING THE NEXT DAY OR SO AS A
MID-TROPOSPHERIC RIDGE TEMPORARILY BUILDS TO THE NORTH OF THE
TROPICAL CYCLONE. THE GFDL MODEL EVEN DEPICTS A TURN TOWARD THE
WEST-SOUTHWEST IN 12 HOURS OR SO. BY 48 HOURS...HOWEVER...A VERY
LARGE 500 MB TROUGH MOVING EASTWARD NEAR THE U.S. EAST COAST SHOULD
INDUCE A TURN TOWARD THE NORTHWEST AND NORTH-NORTHWEST. IN 3 TO 5
DAYS HELENE SHOULD BEGIN TO BE STEERED BY THE FLOW ON THE SOUTHERN
PART OF THE TROUGH AND TURN TOWARD THE NORTH AND NORTHEAST. THE
OFFICIAL FORECAST FOR THIS ADVISORY PACKAGE IS IN REASONABLE
AGREEMENT WITH THE DYNAMICAL MODEL CONSENSUS AS WELL AS THE
GFDL...AND ALSO SIMILAR TO THE PREVIOUS NHC TRACK.

FORECAST POSITIONS AND MAX WINDS

INITIAL 19/0300Z 24.2N 51.4W 100 KT
12HR VT 19/1200Z 24.6N 52.7W 105 KT
24HR VT 20/0000Z 25.0N 54.4W 110 KT
36HR VT 20/1200Z 25.4N 55.9W 110 KT
48HR VT 21/0000Z 26.7N 57.1W 110 KT
72HR VT 22/0000Z 31.0N 58.0W 100 KT
96HR VT 23/0000Z 35.5N 56.0W 90 KT
120HR VT 24/0000Z 39.0N 51.0W 80 KT

$$
FORECASTER PASCH

[dixiebreeze]

Luis, I suppose it's my imagination, but that second trof is looking less strong as time goes on. With the GFDL taking Helen possibly even a bit SW soon before an "expected" recurve, I can't help but wonder if she might not get a lot closer to an east coast landfall than some might think. Thoughts?

[AJC3]

Luis, I suppose it's my imagination, but that second trof is looking less strong as time goes on. With the GFDL taking Helen possibly even a bit SW soon before an "expected" recurve, I can't help but wonder if she might not get a lot closer to an east coast landfall than some might think. Thoughts?

http://www.rap.ucar.edu/weather/upper/upaCNTR_500.gif

This is a large, deep trough. The base extends down to the gulf coast. It is very, very, very unlikely for this trough to not pick up Helene once it moves offshore.

eek...mods feel free to move this to the discussion thread...my bad

[senorpepr]

WTNT33 KNHC 190844
TCPAT3
BULLETIN
HURRICANE HELENE ADVISORY NUMBER 28
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL082006
500 AM AST TUE SEP 19 2006

...HELENE STILL A LARGE CATEGORY THREE HURRICANE...

AT 500 AM AST...0900Z...THE CENTER OF MAJOR HURRICANE HELENE WAS
LOCATED NEAR LATITUDE 24.4 NORTH...LONGITUDE 52.1 WEST OR ABOUT 945
MILES...1520 KM...EAST-SOUTHEAST OF BERMUDA.

HELENE IS MOVING TOWARD THE WEST-NORTHWEST NEAR 8 MPH...13 KM/HR...
AND A WEST TO WEST-NORTHWESTWARD MOTION IS EXPECTED FOR THE NEXT
24 HOURS.

MAXIMUM SUSTAINED WINDS ARE NEAR 115 MPH...185 KM/HR...WITH HIGHER
GUSTS. SOME STRENGTHENING IS FORECAST DURING THE NEXT 24 HOURS.

HELENE REMAINS A LARGE HURRICANE. HURRICANE FORCE WINDS EXTEND
OUTWARD UP TO 70 MILES...110 KM...FROM THE CENTER...AND TROPICAL
STORM FORCE WINDS EXTEND OUTWARD UP TO 230 MILES...370 KM.

ESTIMATED MINIMUM CENTRAL PRESSURE IS 960 MB...28.35 INCHES.

REPEATING THE 500 AM AST POSITION...24.4 N...52.1 W. MOVEMENT
TOWARD...WEST-NORTHWEST NEAR 8 MPH. MAXIMUM SUSTAINED WINDS...115
MPH. MINIMUM CENTRAL PRESSURE...960 MB.

THE NEXT ADVISORY WILL BE ISSUED BY THE NATIONAL HURRICANE CENTER AT
1100 AM AST.

$$
FORECASTER BROWN/STEWART




WTNT43 KNHC 190846
TCDAT3
HURRICANE HELENE DISCUSSION NUMBER 28
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL082006
500 AM EDT TUE SEP 19 2006

AS NOTED IN THE PREVIOUS DISCUSSION...THE CLOUD PATTERN ASSOCIATED
WITH HELENE HAS BECOME ELONGATED NORTH TO SOUTH. A 0449 UTC
AQUA MICROWAVE OVERPASS SUGGESTED THAT THE EYEWALL WAS OPEN TO THE
SOUTHWEST...BUT THERE HAS BEEN LITTLE OVERALL CHANGE IN THE
SATELLITE APPEARANCE AROUND THE CORE OF THE HURRICANE. DVORAK
INTENSITY T-NUMBERS REMAIN 5.5 FROM ALL AGENCIES AND THE INITIAL
INTENSITY WILL REMAIN 100 KT. CONDITIONS APPEAR FAVORABLE FOR
FURTHER STRENGTHENING AS SHEAR IS FORECAST TO REMAIN LIGHT AND SSTS
WARM. THE OFFICIAL INTENSITY FORECAST IS A LITTLE HIGHER THAN THE
AVAILABLE GUIDANCE AND IT IS POSSIBLE THAT HELENE COULD BECOME A
CATEGORY 4 HURRICANE DURING THE NEXT DAY OR TWO.

THE ANTICIPATED WESTWARD MOTION APPEARS TO HAVE STARTED AS INDICATED
BY AN INITIAL MOTION OF 285/7. IN FACT...THE MOTION OVER THE PAST
FEW HOURS HAS BEEN NEARLY DUE WEST. THE DYNAMICAL MODELS AGREE ON
A GENERAL WESTWARD MOVEMENT DURING THE NEXT 24 HOURS AS A
MID-TROPOSPHERIC RIDGE TEMPORARILY BUILDS NORTH OF HELENE AS
HURRICANE GORDON CONTINUES TO MOVE EASTWARD. THE GFDL MODEL
ACTUALLY FORECASTS A SLIGHTLY SOUTH OF DUE WEST MOTION TODAY. IN A
COUPLE OF DAYS...THE RIDGE IS FORECAST TO SHIFT EASTWARD AS A LARGE
MID- TO UPPER-LEVEL TROUGH APPROACHES THE EAST COAST OF THE UNITED
STATES. THIS SHOULD ALLOW THE HURRICANE TO TURN NORTHWARD AND
EVENTUALLY NORTHEASTWARD AHEAD OF THIS TROUGH. THE OFFICIAL
FORECAST IS VERY CLOSE TO THE PREVIOUS ADVISORY THROUGH 36
HOURS...THEREAFTER IT IS ADJUSTED A LITTLE EASTWARD CLOSE TO THE
MODEL CONSENSUS AND THE GFDL TRACK. AT DAYS 4 AND 5...THE NHC
FORECAST IS A LITTLE FASTER THAN THE PREVIOUS ADVISORY AND IS CLOSE
TO THE GFS ENSEMBLE MEAN...BUT IT IS NOT AS FAST AS THE OPERATIONAL
GFS OR GFDL MODELS.

FORECAST POSITIONS AND MAX WINDS

INITIAL 19/0900Z 24.4N 52.1W 100 KT
12HR VT 19/1800Z 24.6N 53.4W 105 KT
24HR VT 20/0600Z 25.1N 55.0W 110 KT
36HR VT 20/1800Z 26.4N 56.3W 110 KT
48HR VT 21/0600Z 28.3N 57.1W 110 KT
72HR VT 22/0600Z 33.6N 56.1W 100 KT
96HR VT 23/0600Z 38.0N 52.0W 90 KT
120HR VT 24/0600Z 42.0N 45.0W 80 KT

$$
FORECASTER BROWN/STEWART




WTNT23 KNHC 190845
TCMAT3
HURRICANE HELENE FORECAST/ADVISORY NUMBER 28
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL082006
0900 UTC TUE SEP 19 2006

HURRICANE CENTER LOCATED NEAR 24.4N 52.1W AT 19/0900Z
POSITION ACCURATE WITHIN 20 NM

PRESENT MOVEMENT TOWARD THE WEST-NORTHWEST OR 285 DEGREES AT 7 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 960 MB
EYE DIAMETER 20 NM
MAX SUSTAINED WINDS 100 KT WITH GUSTS TO 120 KT.
64 KT....... 60NE 50SE 40SW 50NW.
50 KT.......100NE 75SE 60SW 100NW.
34 KT.......200NE 150SE 125SW 175NW.
12 FT SEAS..375NE 375SE 240SW 330NW.
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 24.4N 52.1W AT 19/0900Z
AT 19/0600Z CENTER WAS LOCATED NEAR 24.3N 51.8W

FORECAST VALID 19/1800Z 24.6N 53.4W
MAX WIND 105 KT...GUSTS 130 KT.
64 KT... 60NE 50SE 40SW 50NW.
50 KT...100NE 75SE 60SW 100NW.
34 KT...200NE 150SE 125SW 175NW.

FORECAST VALID 20/0600Z 25.1N 55.0W
MAX WIND 110 KT...GUSTS 135 KT.
64 KT... 60NE 50SE 40SW 50NW.
50 KT...100NE 75SE 60SW 100NW.
34 KT...200NE 150SE 125SW 175NW.

FORECAST VALID 20/1800Z 26.4N 56.3W
MAX WIND 110 KT...GUSTS 135 KT.
64 KT... 60NE 50SE 40SW 50NW.
50 KT...100NE 75SE 60SW 100NW.
34 KT...225NE 175SE 150SW 175NW.

FORECAST VALID 21/0600Z 28.3N 57.1W
MAX WIND 110 KT...GUSTS 135 KT.
50 KT...100NE 75SE 60SW 100NW.
34 KT...225NE 175SE 150SW 175NW.

FORECAST VALID 22/0600Z 33.6N 56.1W
MAX WIND 100 KT...GUSTS 120 KT.
50 KT...100NE 75SE 60SW 100NW.
34 KT...225NE 175SE 150SW 175NW.

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 23/0600Z 38.0N 52.0W
MAX WIND 90 KT...GUSTS 110 KT.

OUTLOOK VALID 24/0600Z 42.0N 45.0W
MAX WIND 80 KT...GUSTS 100 KT.

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 24.4N 52.1W

NEXT ADVISORY AT 19/1500Z

$$
FORECASTER BROWN/STEWART

[cycloneye]

073
WTNT33 KNHC 191449
TCPAT3
BULLETIN
HURRICANE HELENE ADVISORY NUMBER 29
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL082006
ISSUED BY THE HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
1100 AM AST TUE SEP 19 2006

...HELENE STILL A LARGE CATEGORY THREE HURRICANE...

AT 1100 AM AST...1500Z...THE CENTER OF HURRICANE HELENE WAS LOCATED
NEAR LATITUDE 24.6 NORTH...LONGITUDE 52.9 WEST OR ABOUT 895 MILES...
1445 KM...EAST-SOUTHEAST OF BERMUDA.

HELENE IS MOVING TOWARD THE WEST-NORTHWEST NEAR 9 MPH...15 KM/HR...
AND THIS MOTION IS EXPECTED FOR THE NEXT 24 HOURS.

MAXIMUM SUSTAINED WINDS ARE NEAR 115 MPH...185 KM/HR...WITH HIGHER
GUSTS. SOME STRENGTHENING IS FORECAST DURING THE NEXT 24 HOURS.

HURRICANE FORCE WINDS EXTEND OUTWARD UP TO 70 MILES...110 KM...FROM
THE CENTER...AND TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 230
MILES...370 KM.

ESTIMATED MINIMUM CENTRAL PRESSURE IS 960 MB...28.35 INCHES.

REPEATING THE 1100 AM AST POSITION...24.6 N...52.9 W. MOVEMENT
TOWARD...WEST-NORTHWEST NEAR 9 MPH. MAXIMUM SUSTAINED WINDS...115
MPH. MINIMUM CENTRAL PRESSURE...960 MB.

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

$$
FORECASTER MUSHER

[cycloneye]

984
WTNT43 KNHC 191454
TCDAT3
HURRICANE HELENE DISCUSSION NUMBER 29
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL082006
ISSUED BY THE HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
1100 AM EDT TUE SEP 19 2006

HURRICANE HELENE REMAINS AN IMPRESSIVE TROPICAL CYCLONE THIS
MORNING. THE SYSTEM IS SLIGHTLY ELONGATED BUT MAINTAINS ITS CENTRAL
CORE OF DEEP CONVECTION... EYE FEATURE AND ALMOST PERFECT OUTFLOW.
DVORAK INTENSITY T-NUMBERS PERSIST AT 5.5 FROM ALL AGENCIES... THE
INITIAL INTENSITY WILL REMAIN AT 100 KTS AND THE INITIAL MOTION
WILL BE 285/7.

AT THIS MOMENT AND FOR THE NEXT 24 HOURS OR SO... HELENE WILL REMAIN
UNDER A DOMINANT UPPER-LEVEL RIDGE BASED OVER THE CENTRAL ATLANTIC.
THIS RIDGE WILL SHOULD STEER HELENE OFF TO THE WEST NORTHWEST FOR
THE NEXT 24 TO 36 HOURS AND PERHAPS ALLOW FOR SOME FURTHER
STRENGTHENING. A LARGE UPPER LOW... JUST OFF THE EAST COAST... AND
VERY AMPLFIED UPPER-LEVEL TROUGH... OVER THE EASTERN STATES... WILL
THEN PHASE AND BEGIN TO INFLUENCE HELENE. THE UPPER RIDGE OVER THE
ATLANTIC WILL BREAK DOWN... HELENE WILL GET CAUGHT UP IN THE STRONG
WESTERLIES AND BEGIN TO RECURVE/PROGRESS RAPIDLY DOWNSTREAM INTO
THE OPEN WATERS OF THE NORTH ATLANTIC. AFTER 36 HOURS...
HELENE SHOULD BEGIN TO GRADUALLY WEAKEN.

THE DYNAMICAL MODELS/OBJECTIVE AIDS AND GLOBAL MODELS ARE TIGHTLY
CLUSTERED WITH THIS OVERALL TRACK AND RECURVATURE BEFORE 60W. THE
ONLY SPREAD WITH THE GUIDANCE IS THE FORWARD SPEED AS HELENE TURNS
NORTHWARD AND THE WESTERLIES BECOME INVOLVED. THE OPERATIONAL GFS
IS THE MOST PROGRESSIVE WHILE THE UKMET AND ESPECIALLY THE HI-RES
ECMWF ARE THE SLOWEST SOLUTIONS INTO THE MEDIUM RANGE PERIOD. HPC
WILL FOLLOW THE CLOSE CONSENSUS OF THE DYNAMICAL MODELS... WHICH IS
A COMPROMISE OF THESE TWO IDEAS.

FORECAST POSITIONS AND MAX WINDS

INITIAL 19/1500Z 24.6N 52.9W 100 KT
12HR VT 20/0000Z 25.0N 54.1W 105 KT
24HR VT 20/1200Z 25.9N 55.7W 110 KT
36HR VT 21/0000Z 27.5N 56.5W 110 KT
48HR VT 21/1200Z 29.7N 56.7W 105 KT
72HR VT 22/1200Z 35.0N 55.0W 100 KT
96HR VT 23/1200Z 39.5N 49.5W 90 KT
120HR VT 24/1200Z 45.0N 40.5W 80 KT

$$
FORECASTER MUSHER

[cycloneye]

946
WTNT33 KNHC 192050
TCPAT3
BULLETIN
HURRICANE HELENE ADVISORY NUMBER 30
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL082006
ISSUED BY THE HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
500 PM AST TUE SEP 19 2006

AT 500 PM AST...2100Z...THE CENTER OF HURRICANE HELENE WAS LOCATED
NEAR LATITUDE 24.6 NORTH...LONGITUDE 54.1 WEST OR ABOUT 840 MILES...
1350 KM...SOUTHEAST OF BERMUDA.

HELENE IS MOVING TOWARD THE WEST-NORTHWEST NEAR 9 MPH...15 KM/HR...
AND THIS MOTION IS EXPECTED TO CONTINUE FOR THE NEXT SIX TO TWELVE
HOURS.

MAXIMUM SUSTAINED WINDS ARE NEAR 110 MPH...175 KM/HR...WITH HIGHER
GUSTS. LITTLE CHANGE IN STRENGTH IS FORECAST DURING THE NEXT 24
HOURS.

HURRICANE FORCE WINDS EXTEND OUTWARD UP TO 65 MILES...100 KM...FROM
THE CENTER...AND TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 220
MILES...350 KM.

ESTIMATED MINIMUM CENTRAL PRESSURE IS 956 MB...28.23 INCHES.

REPEATING THE 500 PM AST POSITION...24.6 N...54.1 W. MOVEMENT
TOWARD...WEST-NORTHWEST NEAR 9 MPH. MAXIMUM SUSTAINED WINDS...110
MPH. MINIMUM CENTRAL PRESSURE...956 MB.

THE NEXT ADVISORY WILL BE ISSUED BY THE NATIONAL HURRICANE CENTER AT
1100 PM AST.

$$
FORECASTER MUSHER

WTNT43 KNHC 192051
TCDAT3
HURRICANE HELENE DISCUSSION NUMBER 30
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL082006
ISSUED BY THE HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
500 PM EDT TUE SEP 19 2006

A NOAA AIRCRAFT MADE A COUPLE OF PASSES THROUGH HURRICANE HELENE
EARLY THIS AFTERNOON. THE ESTIMATED PRESSURE OF 960 MB THIS MORNING
APPEARED CORRECT AS THE PLANE MEASURED 958 MB BEFORE DEEPENING
ANOTHER 2 MB AN HOUR LATER. THE MAX FLIGHT LEVEL WIND WAS 98 KNOTS
AT 850 MB IN THE NORTHWEST QUADRANT AND TWO EYE WALLS WERE
PRESENT... 40NM AND 120NM OUT RESPECTIVELY. MICROWAVE SATELLITE
DATA ALSO INDICATED THESE TWO EYEWALL FEATURES THIS MORNING.
DESPITE THE PRESSURE LOWERING SLIGHTLY... THE 90 PERCENT REDUCTION
RULE CONCERNING MAX FLIGHT LEVEL WINDS SUGGESTS A 95 KNOT
HURRICANE. PLUS... THIS PRESENT EYEWALL CYCLE WOULD SUGGEST SLIGHT
FILLING OF THE CYCLONE AND THE WINDS LIKELY BROADENING THROUGHOUT
THE SYSTEM. OTHERWISE HELENE SHOWS TRUE SYMMETRY... A DEEP CENTRAL
DENSE OVERCAST AND A WELL-DEFINED EYE FEATURE ALL INDICATIVE OF A
MATURE HURRICANE UNDERGOING FLUCTUATIONS IN INTENSITY.

THE INITIAL MOTION IS 300 DEGREES AT 8 KTS AND THIS MOTION SHOULD
PERSIST INTO WEDNESDAY MORNING. THE TRACK FORECAST REMAINS VERY
CONSISTENT... A QUICK RECURVATURE TO THE NORTH... EVENTUALLY OFF TO
THE NORTHEAST AND PICKING UP FORWARD MOMENTUM. THE GLOBAL MODELS
AND OBJECTIVE AIDS SUGGEST THIS AS THE UPPER LOW AND AMPLIFIED
UPPER TROUGH UPSTREAM NEAR THE EAST COAST BREAKS DOWN THE
SUBTROPICAL RIDGE OVER THE CENTRAL ATLANTIC. HELENE SHOULD BEGIN
THIS NORTHWARD TREND DURING THE DAY ON WEDNESDAY AND BEFORE
REACHING 60W LONGITUDE. HPC GENERALLY FOLLOWED THE TIGHTLY
CLUSTERED OPERATIONAL RUNS OF THE GFS/GFDL AND UKMET ALONG WITH
DYNAMICAL GUIDANCE.

FORECAST POSITIONS AND MAX WINDS

INITIAL 19/2100Z 24.6N 54.1W 95 KT
12HR VT 20/0600Z 25.2N 55.2W 95 KT
24HR VT 20/1800Z 26.7N 56.5W 100 KT
36HR VT 21/0600Z 28.9N 56.8W 95 KT
48HR VT 21/1800Z 32.0N 56.3W 90 KT
72HR VT 22/1800Z 39.0N 51.5W 90 KT
96HR VT 23/1800Z 45.3N 41.0W 80 KT
120HR VT 24/1800Z 49.0N 30.5W 70 KT EXTRATROPICAL

$$
FORECASTER MUSHER

[cycloneye]

631
WTNT33 KNHC 200226
TCPAT3
BULLETIN
HURRICANE HELENE ADVISORY NUMBER 31
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL082006
1100 PM AST TUE SEP 19 2006

...HELENE CHURNING WESTWARD OVER OPEN WATERS...A TURN TO THE
NORTHWEST LIKELY ON WEDNESDAY...

AT 1100 PM AST...0300Z...THE CENTER OF HURRICANE HELENE WAS LOCATED
NEAR LATITUDE 24.6 NORTH...LONGITUDE 54.8 WEST OR ABOUT 805 MILES...
1300 KM...SOUTHEAST OF BERMUDA.

HELENE IS MOVING TOWARD THE WEST NEAR 9 MPH...15 KM/HR...AND A TURN
TO THE NORTHWEST IS LIKELY ON WEDNESDAY.

MAXIMUM SUSTAINED WINDS ARE NEAR 110 MPH...175 KM/HR...WITH HIGHER
GUSTS. HELENE COULD REGAIN MAJOR HURRICANE STATUS ON WEDNESDAY.

HURRICANE FORCE WINDS EXTEND OUTWARD UP TO 45 MILES...75 KM...FROM
THE CENTER...AND TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 200
MILES...325 KM.

ESTIMATED MINIMUM CENTRAL PRESSURE IS 958 MB...28.29 INCHES.

REPEATING THE 1100 PM AST POSITION...24.6 N...54.8 W. MOVEMENT
TOWARD...WEST NEAR 9 MPH. MAXIMUM SUSTAINED WINDS...110 MPH.
MINIMUM CENTRAL PRESSURE...958 MB.

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

$$
FORECASTER COBB/PASCH

[cycloneye]

731
WTNT43 KNHC 200243
TCDAT3
HURRICANE HELENE DISCUSSION NUMBER 31
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL082006
1100 PM EDT TUE SEP 19 2006

SATELLITE INTENSITY ESTIMATES AVERAGE NEAR 100 KT FROM TAFB...SAB
AND AFWA. HOWEVER...A 2039 UTC TRMM OVERPASS INDICATED THAT HELENE
WAS IN THE MIDDLE OF AN EYEWALL REPLACEMENT CYCLE WHICH SUGGESTS
THE SLIGHT FILLING OF THE CYCLONE IS NOT YET FINISHED. IN ADDITION
RECENT INFRARED SATELLITE IMAGERY SHOWS SOME ASYMMETRIES IN THE
DEEP CONVECTION WITH A FAIRLY RAGGED EYE AS WELL. THE INITIAL
INTENSITY IS KEPT AT 95 KT FOR THIS ADVISORY.

THE INITIAL MOTION IS 275 DEGREES AT 8 KT...HOWEVER A TURN TOWARD
THE WEST-NORTHWEST AND NORTHWEST IS EXPECTED SOON. THE TRACK MODEL
GUIDANCE IS TIGHTLY CLUSTERED THROUGH 48-72 HOURS AND VARIES WITH
FORWARD SPEED THEREAFTER. THE GFDL MODEL AND GUNA CONSENSUS WERE
FOLLOWED CLOSELY FOR THIS PACKAGE SINCE THESE MODELS HAVE EXHIBITED
THE BEST PERFORMANCE THUS FAR WITH HELENE. THE OFFICIAL FORECAST IS
SIMILAR TO THE PREVIOUS ADVISORY AND INDICATES A QUICK RECURVATURE
TO THE NORTH IN THE NEXT 12-24 HOURS...AND ACCELERATION TO THE
NORTHEAST AFTER 48 HOURS ON THE SOUTHEAST SIDE OF A LARGE 500 MB
TROUGH MOVING OFF THE U.S. EAST COAST.

HELENE REMAINS IN A LOW SHEAR ENVIRONMENT FOR NOW WITH STRONG UPPER
TROPOSPHERIC OUTFLOW OVER ALL BUT THE SOUTHWEST PORTION OF THE
CIRCULATION. ONCE THE EYEWALL REPLACEMENT IS COMPLETED THERE IS THE
POTENTIAL FOR SOME STRENGTHENING AND HELENE COULD REGAIN MAJOR
HURRICANE STATUS IN THE NEXT 12-24 HOURS. BEYOND 36 HOURS
INCREASING SOUTHWESTERLY SHEAR IS LIKELY TO BRING ABOUT GRADUAL
WEAKENING. BY 96 HOURS...GLOBAL MODELS...SUCH AS THE GFS...SHOW
CONSIDERABLE COLD AIR ADVECTION OVER THE SOUTHWESTERN SEMICIRCLE OF
THE CYCLONE...JUSTIFYING A FORECAST OF TRANSITION TO A STRONG
EXTRATROPICAL STORM AROUND THAT TIME.

FORECAST POSITIONS AND MAX WINDS

INITIAL 20/0300Z 24.6N 54.8W 95 KT
12HR VT 20/1200Z 25.5N 55.7W 100 KT
24HR VT 21/0000Z 27.5N 56.8W 100 KT
36HR VT 21/1200Z 30.0N 56.8W 95 KT
48HR VT 22/0000Z 32.7N 56.0W 95 KT
72HR VT 23/0000Z 39.0N 50.0W 85 KT
96HR VT 24/0000Z 45.0N 40.0W 75 KT...EXTRATROPICAL
120HR VT 25/0000Z 49.0N 30.0W 60 KT...EXTRATROPICAL

$$
FORECASTER COBB/PASCH

[Thunder44]

000
WTNT33 KNHC 200844
TCPAT3
BULLETIN
HURRICANE HELENE ADVISORY NUMBER 32
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL082006
500 AM AST WED SEP 20 2006

...HELENE MOVING NORTHWESTWARD AND EXPECTED TO REMAIN WELL TO THE
EAST OF BERMUDA...

AT 500 AM AST...0900Z...THE CENTER OF HURRICANE HELENE WAS LOCATED
NEAR LATITUDE 25.3 NORTH...LONGITUDE 55.4 WEST OR ABOUT 745 MILES...
1200 KM...SOUTHEAST OF BERMUDA.

HELENE IS MOVING TOWARD THE NORTHWEST NEAR 9 MPH...15 KM/HR. A
GRADUAL TURN TOWARD THE NORTH IS EXPECTED DURING THE NEXT 24 HOURS
...AND HELENE IS FORECAST TO REMAIN WELL TO THE EAST OF BERMUDA.

MAXIMUM SUSTAINED WINDS ARE NEAR 110 MPH...175 KM/HR...WITH HIGHER
GUSTS. SLIGHT STRENGTHENING IS POSSIBLE DURING THE NEXT 24 HOURS...
AND HELENE COULD REGAIN MAJOR HURRICANE STATUS LATER TODAY OR
THURSDAY.

HURRICANE FORCE WINDS EXTEND OUTWARD UP TO 45 MILES...75 KM...FROM
THE CENTER...AND TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 200
MILES...325 KM.

THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 958 MB...28.29 INCHES.

REPEATING THE 500 AM AST POSITION...25.3 N...55.4 W. MOVEMENT
TOWARD...NORTHWEST NEAR 9 MPH. MAXIMUM SUSTAINED WINDS...110 MPH.
MINIMUM CENTRAL PRESSURE...958 MB.

THE NEXT ADVISORY WILL BE ISSUED BY THE NATIONAL HURRICANE CENTER AT
1100 AM AST.

$$
FORECASTER STEWART

[Thunder44]

000
WTNT43 KNHC 200838
TCDAT3
HURRICANE HELENE DISCUSSION NUMBER 32
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL082006
500 AM EDT WED SEP 20 2006

SATELLITE INTENSITY ESTIMATES ARE A CONSENSUS T5.5/102 KT.
HOWEVER...THE EYE FEATURE IN INFRARED SATELLITE IMAGERY HAS BECOME
RAGGED AND LESS DISTINCT...SO THE INITIAL INTENSITY WILL REMAIN AT
95 KT FOR THIS ADVISORY. UPPER-LEVEL OUTFLOW REMAINS EXCELLENT IN
ALL QUADRANTS...EXCEPT SLIGHTLY RESTRICTED TO THE SOUTHWEST.

THE INITIAL MOTION ESTIMATE IS NOW 305/08 KT. THE LONG ANTICIPATED
TURN TOWARD THE NORTHWEST THAT ALL OF THE GLOBAL AND REGIONAL
MODELS HAVE BEEN ADVERTISING FOR THE PAST FEW DAYS APPEARS TO
FINALLY BE UNDERWAY. A NARROW AND ELONGATED MID-LEVEL TROUGH
BETWEEN 65W-70W LONGITUDE IS EXPECTED TO SLOWLY TURN HELENE MORE
NORTHWARD DURING THE NEXT 36 HOURS...WITH A LARGER AND MORE
HIGHLY-AMPLIFIED TROUGH FORECAST TO MOVE EASTWARD OFF THE U.S. EAST
COAST AND ACCELERATING THE CYCLONE NORTHEASTWARD AFTER 48 HOURS.
THE OFFICIAL FORECAST TRACK IS SIMILAR TO BUT A LITTLE TO THE RIGHT
OF THE PREVIOUS TRACK AFTER 48 HOURS...AND IS CLOSE TO THE MIDDLE
OF THE TIGHTLY PACKED NHC MODEL GUIDANCE.

THE OUTFLOW PATTERN ON THE WEST SIDE HAS BECOME FLATTENED A LITTLE
BIT AS SOUTHWESTERLY UPPER-LEVEL FLOW AHEAD OF THE TROUGH ALONG
65W-70W LONGITUDE IS BEGINNING TO IMPINGE ON THE CYCLONE. THIS
SLIGHTLY UNFAVORABLE FLOW PATTERN SHOULD INHIBIT THE
INTENSIFICATION PROCESS...BUT THE SHEAR WILL STILL BE LOW ENOUGH
AND THE SSTS WARM ENOUGH TO ALLOW FOR SOME STRENGTHENING...AND
HELENE COULD BECOME A MAJOR HURRICANE AGAIN BEFORE IT BEGINS TO
RECURVE IN 36 HOURS. AFTER THAT...STEADILY INCREASING SOUTHWESTERLY
VERTICAL SHEAR COUPLED WITH DECREASING SSTS SHOULD INITIATE A SLOW
WEAKENING TREND. BY 72-96 HOURS...A TRANSITION OVER TO A POWERFUL
EXTRATROPICAL LOW PRESSURE IS EXPECTED AS THE LARGE TROUGH OVER THE
EASTERN U.S. MOVES EASTWARD AND EVENTUALLY CAPTURES HELENE.

FORECAST POSITIONS AND MAX WINDS

INITIAL 20/0900Z 25.3N 55.4W 95 KT
12HR VT 20/1800Z 26.4N 56.3W 100 KT
24HR VT 21/0600Z 28.6N 56.9W 100 KT
36HR VT 21/1800Z 31.0N 56.7W 95 KT
48HR VT 22/0600Z 33.9N 55.0W 90 KT
72HR VT 23/0600Z 39.7N 48.0W 80 KT
96HR VT 24/0600Z 45.0N 38.0W 70 KT...BECOMING EXTRATROPICAL
120HR VT 25/0600Z 49.0N 29.0W 60 KT...EXTRATROPICAL

$$
FORECASTER STEWART

[Evil Jeremy]

000
WTNT43 KNHC 201436
TCDAT3
HURRICANE HELENE DISCUSSION NUMBER 33
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL082006
1100 AM EDT WED SEP 20 2006

THE SATELLITE PRESENTATION ASSOCIATED WITH HELENE HAS DEGRADED THIS
MORNING AS THE EYE IS NO LONGER EVIDENT AND THE CENTRAL CORE
CONVECTION HAS BECOME LESS SYMMETRIC. WHILE SATELLITE INTENSITY
ESTIMATES ARE UNCHANGED AT 102 KT FROM BOTH TAFB AND SAB...THE
ACTUAL DATA T VALUES ARE MUCH LOWER AT 77 KT. THE INITIAL
INTENSITY IS LOWERED TO 90 KT GIVEN THESE DATA. THE REASONS FOR
THE CURRENT WEAKENING ARE NOT READILY APPARENT. MICROWAVE DATA FROM
YESTERDAY SUGGESTED THAT HELENE WAS ENTERING AN EYEWALL REPLACEMENT
CYCLE WHICH MAY HAVE NOT YET COMPLETED. ADDITIONALLY...WATER VAPOR
IMAGERY SHOWS THAT UPPER LEVEL OUTFLOW IS NOW RESTRICTED TO THE
SOUTHWEST INDICATING THAT VERTICAL SHEAR AND MIDDLE TO UPPER LEVEL
DRY AIR IS IMPINGING UPON THE CYCLONE. GIVEN THE AFOREMENTIONED
UNCERTAINTIES...THE INTENSITY FORECAST IS TRICKY. IF THE EYEWALL
REPLACEMENT CYCLE DOES NOT COMPLETE OR THE SHEAR DOES NOT RELAX...
ADDITIONAL WEAKENING IS POSSIBLE. FURTHER COMPLICATING MATTERS IS
A LARGE MIDDLE TO UPPER TROPOSPHERIC TROUGH CURRENTLY MOVING OFF
THE EAST COAST OF THE UNITED STATES WHICH MAY PROVIDE A TEMPORARY
SHOT OF DIFFLUENT FLOW ALOFT TOMORROW FOLLOWED BY INCREASING SHEAR.
THEREAFTER...THE CYCLONE IS EXPECTED TO START INTERACTING WITH THE
ATTENDANT BAROCLINIC ZONE ULTIMATELY RESULTING IN THE SYSTEM
BEGINNING EXTRATROPICAL TRANSITION IN 72 HOURS. DURING THE
EXTRATROPICAL TRANSITION...HELENE WILL BE SITUATED NEAR THE RIGHT
ENTRANCE REGION OF A STRONG UPPER-LEVEL JET WHICH MAY PROVIDE
ENOUGH ENERGY TO PREVENT WEAKENING.

HELENE IS MOVING A LITTLE LEFT OF THE PREVIOUS ADVISORY WITH AN
INITIAL MOTION ESTIMATE OF 315/10. THE LONG ANTICIPATED
TURN TOWARD THE NORTHWEST APPEARS TO BE UNDERWAY. GLOBAL MODELS ARE
TIGHTLY CLUSTERED ABOUT A GRADUAL NORTHWARD TURN DURING THE NEXT 36
HOURS FOLLOWED BY AN ACCELERATION NORTHEASTWARD AHEAD OF A LARGE
TROUGH MOVING INTO THE WESTERN ATLANTIC. THE OFFICIAL FORECAST IS
NUDGED A LITTLE TO THE LEFT AND IS SLIGHTLY SLOWER THAN THE
PREVIOUS ADVISORY THROUGH 72 HOURS AND IS LITTLE CHANGED
THEREAFTER.

EVEN THOUGH HELENE IS FORECAST TO RECURVE OVER THE OPEN WATERS OF
THE CENTRAL ATLANTIC...LONG PERIOD SWELLS ARE ALREADY REGISTERING
AT SEVERAL EAST COAST BUOYS.

FORECAST POSITIONS AND MAX WINDS

INITIAL 20/1500Z 26.0N 56.3W 90 KT
12HR VT 21/0000Z 27.3N 57.0W 90 KT
24HR VT 21/1200Z 29.4N 57.3W 95 KT
36HR VT 22/0000Z 32.3N 56.4W 90 KT
48HR VT 22/1200Z 35.0N 54.5W 85 KT
72HR VT 23/1200Z 40.5N 47.0W 85 KT...BECOMING EXTRATROPICAL
96HR VT 24/1200Z 46.0N 36.5W 65 KT...EXTRATROPICAL
120HR VT 25/1200Z 50.0N 28.0W 55 KT...EXTRATROPICAL

$$
FORECASTER RHOME/AVILA

[Evil Jeremy]

000
WTNT33 KNHC 201434
TCPAT3
BULLETIN
HURRICANE HELENE ADVISORY NUMBER 33
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL082006
1100 AM AST WED SEP 20 2006

...HELENE WEAKENS SLIGHTLY OVER THE CENTRAL ATLANTIC...

AT 1100 AM AST...1500Z...THE CENTER OF HURRICANE HELENE WAS LOCATED
NEAR LATITUDE 26.0 NORTH...LONGITUDE 56.3 WEST OR ABOUT 670 MILES...
1080 KM...SOUTHEAST OF BERMUDA.

HELENE IS MOVING TOWARD THE NORTHWEST NEAR 12 MPH...19 KM/HR...AND
A GRADUAL TURN TOWARD THE NORTH IS EXPECTED OVER THE NEXT 24 HOURS.

MAXIMUM SUSTAINED WINDS ARE NEAR 105 MPH...165 KM/HR...WITH HIGHER
GUSTS MAKING HELENE A CATEGORY TWO HURRICANE ON THE SAFFIR-SIMPSON
SCALE. LITTLE CHANGE IN STRENGTH IS FORECAST DURING THE NEXT 24
HOURS.

HURRICANE FORCE WINDS EXTEND OUTWARD UP TO 60 MILES...95 KM...FROM
THE CENTER...AND TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 230
MILES...370 KM.

ESTIMATED MINIMUM CENTRAL PRESSURE IS 958 MB...28.29 INCHES.

REPEATING THE 1100 AM AST POSITION...26.0 N...56.3 W. MOVEMENT
TOWARD...NORTHWEST NEAR 12 MPH. MAXIMUM SUSTAINED WINDS...105 MPH.
MINIMUM CENTRAL PRESSURE...958 MB.

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

$$
FORECASTER RHOME/AVILA