Tropical storm Hanna

[Matthew]

000
WTNT43 KNHC 021455
TCDAT3
TROPICAL STORM HANNA DISCUSSION NUMBER 23
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL082008
1100 AM EDT TUE SEP 02 2008

HANNA HAS FINALLY SUCCUMBED TO THE STRONG VERTICAL SHEAR WITH
VISIBLE SATELLITE IMAGERY SHOWING A PARTIALLY EXPOSED LOW-LEVEL
CIRCULATION AND A SHRINKING CDO FEATURE. THE INITIAL INTENSITY IS
SET AT 60 KT...BUT GIVEN THE CURRENT SATELLITE PRESENTATION...THIS
MIGHT BE A BIT GENEROUS. AN AIR FORCE RECONNAISSANCE AIRCRAFT WILL
INVESTIGATE HANNA THIS AFTERNOON AND PROVIDE A BETTER INTENSITY
ESTIMATE. WATER VAPOR IMAGERY SHOWS A SHARP EDGE OR DEFORMATION
AXIS ON THE NORTH SIDE OF THE CIRRUS CANOPY SUGGESTING THAT THE
SHEAR WILL PERSIST IN THE SHORT-TERM...AND SOME ADDITIONAL
WEAKENING IS POSSIBLE TODAY AND TONIGHT. IN ABOUT 24
HOURS...GLOBAL MODELS SHOW THE SHEAR WEAKENING AND THIS COULD ALLOW
HANNA TO RESTRENGTHEN. HOWEVER...GIVEN THE PRESENT LACK OF
ORGANIZATION...IT IS DIFFICULT TO KNOW HOW MUCH STRENGTHENING IS
POSSIBLE. THE NEW OFFICIAL FORECAST IS LOWER THAN THE PREVIOUS
ADVISORY BUT SHOWS HANNA BECOMING A CATEGORY ONE HURRICANE IN ABOUT
36 HOURS. IT SHOULD BE NOTED THAT THIS IS A LOW CONFIDENCE
FORECAST. IN FACT...IF ONE CONSULTS THE WIND SPEED PROBABILITY
PRODUCT INCLUDED IN THIS PACKAGE...IT CAN BE SEEN THAT THERE IS
NEARLY AN EQUAL PROBABILITY OF HANNA BEING A TROPICAL STORM OR
HURRICANE AT DAY 3.

HANNA CONTINUES TO MEANDER BUT THE BEST ESTIMATE OF AN INITIAL
MOTION IS 250/05. SLOW AND ERRATIC MOTION IS EXPECTED TODAY BUT
HANNA SHOULD START MOVING NORTHWESTWARD TONIGHT OR TOMORROW AS A
LARGE MID-LATITUDE TROUGH OVER THE WESTERN ATLANTIC LIFTS NORTHWARD
AND THE SUBTROPICAL RIDGE BUILDS BACK IN. HANNA SHOULD ACCELERATE
NORTHWESTWARD AT DAYS 2 TO 3 AS THE RIDGE STRENGTHENS. DYNAMICAL
TRACK MODELS HAVE SHIFTED A LITTLE TO THE WEST AND THE NEW OFFICIAL
FORECAST FOLLOWS SUIT. ON THE FORECAST TRACK...HANNA IS EXPECTED TO
APPROACH THE EAST COAST OF FLORIDA... GEORGIA...OR SOUTH CAROLINA
IN 2 TO 3 DAYS. IT SHOULD BE STRESSED THAT THE EXPECTED ANGLE OF
APPROACH AND TRACK UNCERTAINTY MAKE IT IMPOSSIBLE TO NARROW DOWN
THE POTENTIAL IMPACT AREA. INTERESTS IN THE NORTHWESTERN BAHAMAS
AND ALONG THE ENTIRE SOUTHEASTERN UNITED STATES COAST SHOULD
CLOSELY MONITOR THE PROGRESS OF THIS SYSTEM.

FORECAST POSITIONS AND MAX WINDS

INITIAL 02/1500Z 21.0N 73.5W 60 KT
12HR VT 03/0000Z 21.4N 73.7W 55 KT
24HR VT 03/1200Z 22.3N 74.2W 60 KT
36HR VT 04/0000Z 23.6N 75.3W 65 KT
48HR VT 04/1200Z 25.1N 76.8W 70 KT
72HR VT 05/1200Z 29.5N 80.5W 75 KT
96HR VT 06/1200Z 36.5N 80.0W 35 KT...INLAND
120HR VT 07/1200Z 45.5N 70.0W 25 KT...INLAND REMNANT LOW

$$
FORECASTER RHOME/KNABB

[Matthew]

000
WTNT33 KNHC 021756
TCPAT3
BULLETIN
TROPICAL STORM HANNA INTERMEDIATE ADVISORY NUMBER 23A
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL082008
200 PM AST TUE SEP 02 2008

...HANNA CONTINUES TO PRODUCE HEAVY RAINS OVER THE SOUTHEASTERN
BAHAMAS AND HISPANIOLA...

A HURRICANE WARNING REMAINS IN EFFECT FOR THE CENTRAL BAHAMAS...THE
SOUTHEASTERN BAHAMAS...AND THE TURKS AND CAICOS ISLANDS.

A TROPICAL STORM WARNING IS IN EFFECT FOR THE NORTHERN COAST OF
HAITI FROM LE MOLE ST NICHOLAS EASTWARD TO THE NORTHERN BORDER WITH
THE DOMINICAN REPUBLIC. A TROPICAL STORM WARNING MEANS THAT
TROPICAL STORM CONDITIONS ARE EXPECTED WITHIN THE WARNING AREA
WITHIN THE NEXT 24 HOURS.

INTERESTS IN EASTERN CUBA...THE NORTHWESTERN BAHAMAS...AND THE
FLORIDA PENINSULA SHOULD MONITOR THE PROGRESS OF HANNA.

FOR STORM INFORMATION SPECIFIC TO YOUR AREA...PLEASE MONITOR
PRODUCTS ISSUED BY YOUR LOCAL WEATHER OFFICE.

AT 200 PM AST...1800Z...THE CENTER OF TROPICAL STORM HANNA WAS
LOCATED NEAR LATITUDE 20.6 NORTH...LONGITUDE 72.9 WEST OR JUST
SOUTHEAST OF GREAT INAGUA ISLAND IN THE SOUTHEASTERN BAHAMAS AND
ABOUT 420 MILES...680 KM...SOUTHEAST OF NASSAU.

HANNA HAS BEEN DRIFTING SOUTHEASTWARD TODAY. HOWEVER...A
NORTHWESTWARD MOTION IS EXPECTED TO BEGIN TONIGHT OR TOMORROW. ON
THE FORECAST TRACK...HANNA WILL MOVE OVER THE SOUTHEASTERN BAHAMAS
TONIGHT AND INTO THE CENTRAL BAHAMAS TOMORROW.

MAXIMUM SUSTAINED WINDS ARE NEAR 70 MPH...110 KM/HR...WITH HIGHER
GUSTS. LITTLE CHANGE IN STRENGTH IS FORECAST DURING THE NEXT 24
HOURS. AN AIR FORCE RECONNAISSANCE AIRCRAFT IS CURRENTLY
INVESTIGATING HANNA. SOME STRENGTHENING IS POSSIBLE ON WEDNESDAY
AND THURSDAY.

TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 175 MILES...280 KM
FROM THE CENTER.

THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 985 MB...29.09 INCHES.

HANNA IS EXPECTED TO PRODUCE RAINFALL TOTALS OF 4 TO 8 INCHES...
WITH ISOLATED AMOUNTS OF 12 INCHES...OVER THE SOUTHEASTERN BAHAMAS
...THE TURKS AND CAICOS ISLANDS...AND EASTERN CUBA. RAINFALL TOTALS
OF 6 TO 10 INCHES...WITH ISOLATED MAXIMUM AMOUNTS OF UP TO 20
INCHES...ARE POSSIBLE OVER HISPANIOLA WHERE THESE RAINS COULD CAUSE
LIFE-THREATENING MUDSLIDES AND FLASH FLOODING.

COASTAL STORM SURGE FLOODING OF 3 TO 5 FEET ABOVE NORMAL TIDE
LEVELS...ALONG WITH LARGE AND DANGEROUS BATTERING WAVES...CAN BE
EXPECTED IN AREAS OF ONSHORE FLOW WITHIN THE HURRICANE WARNING AREA.

SWELLS FROM HANNA ARE EXPECTED TO INCREASE THE RISK OF DANGEROUS RIP
CURRENTS ALONG PORTIONS OF THE SOUTHEASTERN UNITED STATES COAST
DURING THE NEXT COUPLE OF DAYS.

REPEATING THE 200 PM AST POSITION...20.6 N...72.9 W.
MOVEMENT...DRIFTING SOUTHEASTWARD. MAXIMUM SUSTAINED WINDS...70
MPH. MINIMUM CENTRAL PRESSURE...985 MB.

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

$$
FORECASTER RHOME/KNABB

[Matthew]

000
WTNT43 KNHC 022056
TCDAT3
TROPICAL STORM HANNA DISCUSSION NUMBER 24
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL082008
500 PM EDT TUE SEP 02 2008

AN AIR FORCE RECONNAISSANCE AIRCRAFT CURRENTLY INVESTIGATING HANNA
CONFIRMS THAT THE SYSTEM HAS WEAKENED. THE PEAK FLIGHT-LEVEL WIND
AT 850 MB WAS 66 KT WHICH CORRESPONDS TO ABOUT 55 KT AT THE
SURFACE. HANNA WILL CONTINUE TO ENCOUNTER STRONG SHEAR FOR ANOTHER
12-24 HOURS WHICH SHOULD LIMIT STRENGTHENING IN THE SHORT TERM. BY
TOMORROW...GLOBAL MODELS FORECAST AN UPPER-LEVEL LOW TO CUT OFF
JUST WEST OF HANNA AND THEN DROP SOUTHWARD DURING THE NEXT FEW
DAYS. IF THIS EVOLUTION MATERIALIZES...AND ASSUMING HANNA IS ABLE
TO FIGHT OFF THE SHEAR...THE ENVIRONMENT WOULD GRADUALLY BECOME
MORE FAVORABLE FOR STRENGTHENING. THE OFFICIAL INTENSITY FORECAST
CALLS FOR HANNA TO REGAIN HURRICANE STRENGTH IN A DAY OR SO...IN
LINE WITH NEARLY ALL OF THE AVAILABLE INTENSITY MODELS.
HOWEVER...THE EVOLUTION OF THE LARGE-SCALE ENVIRONMENT OVER THE
NEXT DAY OR SO IS COMPLEX...WHICH RESULTS IN LOWER THAN NORMAL
CONFIDENCE IN THE INTENSITY FORECAST.

THE LAST FEW AIRCRAFT FIXES INDICATE THAT HANNA CONTINUES TO DRIFT
SOUTHEASTWARD WITH AN INITIAL MOTION ESTIMATE OF 150/02. TRACK
MODELS INSIST THAT HANNA WILL START ITS MUCH-ANTICIPATED TURN
TOWARD THE NORTHWEST SOON...AS A LARGE MID-LATITUDE TROUGH OVER THE
WESTERN ATLANTIC LIFTS NORTHWARD AND THE SUBTROPICAL RIDGE BUILDS
BACK IN. SUCH A TRACK WOULD TAKE THE CYCLONE NORTHWESTWARD THROUGH
THE CENTRAL AND NORTHWESTERN BAHAMAS DURING THE NEXT TWO DAYS.
HANNA IS THEN EXPECTED TO ACCELERATE AS IT MAKES ITS APPROACH TO
THE SOUTHEASTERN UNITED STATES. HOWEVER...UNTIL HANNA BEGINS A
MORE DEFINITIVE MOTION...IT WILL BE DIFFICULT TO NARROW THE
POTENTIAL IMPACT AREA. IN ADDITION...THE ANTICIPATED ANGLE OF
APPROACH TO THE SOUTHEAST UNITED STATES COAST MEANS THAN ONLY A
SMALL DEVIATION LEFT OR RIGHT OF THE TRACK WILL HAVE LARGE
IMPLICATIONS IN BOTH TIME AND LOCATION OF LANDFALL. IN FACT...THE
WIND SPEED PROBABILITY PRODUCT INCLUDED WITH THIS ADVISORY PACKAGE
SHOWS THAT THE CHANCES OF HURRICANE-FORCE WINDS ARE ABOUT EQUAL AT
EACH SPECIFIC LOCATION ALONG THE COAST FROM FLORIDA THROUGH THE
CAROLINAS.

FORECAST POSITIONS AND MAX WINDS

INITIAL 02/2100Z 20.4N 72.7W 55 KT
12HR VT 03/0600Z 20.9N 73.1W 55 KT
24HR VT 03/1800Z 22.2N 74.0W 60 KT
36HR VT 04/0600Z 23.5N 75.5W 65 KT
48HR VT 04/1800Z 25.4N 77.2W 70 KT
72HR VT 05/1800Z 30.5N 80.5W 70 KT
96HR VT 06/1800Z 38.0N 78.0W 30 KT...INLAND
120HR VT 07/1800Z 47.0N 66.0W 25 KT...REMNANT LOW

$$
FORECASTER RHOME/KNABB

[Matthew]

000
WTNT43 KNHC 030256
TCDAT3
TROPICAL STORM HANNA DISCUSSION NUMBER 25
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL082008
1100 PM EDT TUE SEP 02 2008

THE LAST COUPLE OF FIXES FROM THE RECONNAISSANCE AIRCRAFT
INDICATED THAT HANNA WAS MOVING SLOWLY EASTWARD. IT SEEMS THAT
HANNA IS MAKING A SMALL COUNTER-CLOCKWISE LOOP BETWEEN HISPANIOLA
AND THE SOUTHEASTERN BAHAMAS. I HAVE TO GIVE SOME CREDIT TO THE
GFDL AND HWRF MODELS WHICH PREDICTED THIS LOOP A FEW DAYS AGO...
HOWEVER THEY INDICATED THAT HANNA WOULD BE A LITTLE FURTHER NORTH
WHEN IT OCCURRED. SINCE THE AIRCRAFT DEPARTED HANNA THE CLOUD
PATTERN HAS CONTINUED TO DEGRADE...AND IT IS POSSIBLE THAT HANNA
HAS WEAKENED EVEN MORE. HOWEVER...WE WILL KEEP THE INITIAL
INTENSITY AT 55 KT SINCE ANOTHER AIRCRAFT IS SCHEDULED TO
INVESTIGATE THE STORM AROUND 0600 UTC.

STRONG NORTHWESTERLY UPPER-LEVEL WINDS CONTINUE TO SHEAR HANNA.
BUT...THE GLOBAL MODELS FORECAST AN UPPER-LEVEL LOW TO CUT-OFF TO
THE NORTHWEST OF HANNA VERY SOON...AND THERE IS SOME EVIDENCE IN
WATER VAPOR IMAGERY THAT THIS IS BEGINNING TO OCCUR. AS THE
UPPER-LOW CUTS-OFF IT IS FORECAST TO DROP SOUTHWARD WHICH SHOULD
TURN THE UPPER-FLOW OVER THE STORM FROM THE SOUTH AND SOUTHEAST...
WHICH WOULD BE MORE FAVORABLE FOR STRENGTHENING DURING THE NEXT
COUPLE OF DAYS. THE NEW INTENSITY FORECAST IS SIMILAR TO THE
PREVIOUS ADVISORY AND IS CLOSE TO THE CONSENSUS OF THE GUIDANCE. AT
96 HOURS...HANNA WAS MAINTAINED AS A TROPICAL STORM...BECAUSE IT IS
PREDICTED TO BE FAIRLY CLOSE TO THE COAST OF THE NORTHEAST UNITED
STATES AND THERE COULD STILL BE TROPICAL STORM FORCE WINDS OVER
WATER AT THAT TIME.

THE TRACK MODELS SUGGEST THAT HANNA WILL BEGIN MOVING NORTHWESTWARD
VERY SOON AS THE LARGE UPPER-LEVEL TROUGH OFF THE NORTHEAST UNITED
STATES COAST LIFTS NORTHWARD...ALLOWING THE SUBTROPICAL RIDGE OVER
THE ATLANTIC TO BUILD WESTWARD. THIS PATTERN IS FORECAST TO STEER
HANNA ON A GENERAL NORTHWESTWARD MOTION WITH SOME INCREASE IN
FORWARD SPEED OVER THE NEXT COUPLE OF DAYS. SOME OF THE TRACK
MODELS HAVE SHIFTED A LITTLE EASTWARD...BUT NOT ENOUGH TO WARRANT A
CHANGE TO THE OFFICIAL FORECAST. THE NEW TRACK HAS BEEN ADJUSTED
EASTWARD DURING THE FIRST 24-36 HOURS DUE TO THE MORE EASTWARD
INITIAL LOCATION...BUT THEREAFTER IT REMAINS VERY CLOSE TO THE
PREVIOUS ADVISORY. AS A REMINDER...ONE SHOULD NOT FOCUS ON THE
EXACT TRACK AS SMALL DEVIATIONS LEFT OR RIGHT WOULD HAVE LARGE
IMPLICATIONS ON BOTH THE TIME AND LOCATION OF LANDFALL. A G-IV
MISSION WAS FLOWN THIS EVENING AND THE DATA GATHERED BY THIS
AIRCRAFT SHOULD GET ASSIMILATED INTO THE 0000 UTC MODEL GUIDANCE.

FORECAST POSITIONS AND MAX WINDS

INITIAL 03/0300Z 20.5N 72.4W 55 KT
12HR VT 03/1200Z 21.3N 72.3W 55 KT
24HR VT 04/0000Z 22.8N 73.6W 60 KT
36HR VT 04/1200Z 24.4N 75.5W 65 KT
48HR VT 05/0000Z 26.4N 77.4W 70 KT
72HR VT 06/0000Z 32.5N 80.5W 75 KT...INLAND
96HR VT 07/0000Z 41.0N 75.5W 35 KT...INLAND
120HR VT 08/0000Z 50.0N 60.0W 35 KT...EXTRATROPICAL

$$
FORECASTER BROWN/AVILA

[Matthew]

000
WTNT33 KNHC 030549
TCPAT3
BULLETIN
TROPICAL STORM HANNA INTERMEDIATE ADVISORY NUMBER 25A
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL082008
200 AM AST WED SEP 03 2008

...HANNA DRIFTING SOUTHWARD TOWARD NORTHERN HAITI...

A HURRICANE WARNING REMAINS IN EFFECT FOR THE CENTRAL BAHAMAS...THE
SOUTHEASTERN BAHAMAS...AND THE TURKS AND CAICOS ISLANDS.

A HURRICANE WATCH IS IN EFFECT FOR THE NORTHWESTERN BAHAMAS...
INCLUDING THE ABACOS...ANDROS ISLAND...BERRY ISLANDS...BIMINI...
ELEUTHERA...GRAND BAHAMA ISLAND...AND NEW PROVIDENCE. A HURRICANE
WATCH MEANS THAT HURRICANE CONDITIONS ARE POSSIBLE WITHIN THE
WARNING AREA...GENERALLY WITHIN THE NEXT 36 HOURS.

A TROPICAL STORM WARNING REMAINS IN EFFECT FOR THE NORTHERN COAST OF
THE DOMINICAN REPUBLIC FROM PUERTO PLATA WESTWARD TO BAHIA DE
MANZANILLO. A TROPICAL STORM WARNING IS ALSO IN EFFECT FOR HAITI
FROM THE NORTHERN BORDER WITH THE DOMINICAN REPUBLIC TO
PORT-AU-PRINCE. A TROPICAL STORM WARNING MEANS THAT TROPICAL STORM
CONDITIONS ARE EXPECTED WITHIN THE WARNING AREA WITHIN THE NEXT 24
HOURS.

INTERESTS IN THE SOUTHEASTERN UNITED STATES SHOULD MONITOR THE
PROGRESS OF HANNA.

FOR STORM INFORMATION SPECIFIC TO YOUR AREA...INCLUDING POSSIBLE
INLAND WATCHES AND WARNINGS...PLEASE MONITOR PRODUCTS ISSUED
BY YOUR LOCAL WEATHER OFFICE.

AT 200 AM AST...0600Z...THE CENTER OF TROPICAL STORM HANNA WAS
LOCATED NEAR LATITUDE 20.1 NORTH...LONGITUDE 72.5 WEST OR JUST EAST
OF ILE DE LA TORTUE HAITI AND ABOUT 80 MILES...130 KM...
SOUTH-SOUTHEAST OF GREAT INAGUA ISLAND.

HANNA HAS BEEN MOVING SOUTHWARD DURING THE PAST FEW HOURS.
HOWEVER...DECREASE IN FORWARD SPEED WITH A TURN TO THE NORTH OR
NORTHWEST IS EXPECTED TO BEGIN LATER TODAY...FOLLOWED BY A
NORTHWESTWARD MOTION WITH SOME INCREASE IN FORWARD SPEED TONIGHT.
ON THE FORECAST TRACK...HANNA IS EXPECTED TO MOVE ACROSS THE
SOUTHEASTERN BAHAMAS LATER TODAY...MOVE NEAR OR OVER THE CENTRAL
BAHAMAS TONIGHT...AND BE NEAR THE NORTHWESTERN BAHAMAS ON THURSDAY.

MAXIMUM SUSTAINED WINDS REMAIN NEAR 65 MPH...100 KM/HR...WITH HIGHER
GUSTS. LITTLE CHANGE IN STRENGTH IS FORECAST TODAY...BUT SOME
STRENGTHENING IS EXPECTED TONIGHT AND THURSDAY...AND HANNA
COULD REGAIN HURRICANE STRENGTH DURING THAT PERIOD.

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

MINIMUM CENTRAL PRESSURE ESTIMATED FROM AIR FORCE RESERVE UNIT
RECONNAISSANCE AIRCRAFT OBSERVATIONS IS 990 MB...29.24 INCHES.

HANNA IS EXPECTED TO PRODUCE RAINFALL TOTALS OF 4 TO 8 INCHES...
WITH MAXIMUM ISOLATED AMOUNTS OF 12 INCHES...OVER THE SOUTHEASTERN
BAHAMAS...THE TURKS AND CAICOS ISLANDS...AND EASTERN CUBA.
RAINFALL TOTALS OF 6 TO 10 INCHES...WITH ISOLATED MAXIMUM AMOUNTS
OF UP TO 15 INCHES...ARE POSSIBLE OVER HISPANIOLA WHERE THESE RAINS
COULD CAUSE LIFE-THREATENING MUD SLIDES AND FLASH FLOODING.

COASTAL STORM SURGE FLOODING OF 2 TO 4 FEET ABOVE NORMAL TIDE
LEVELS...ALONG WITH LARGE AND DANGEROUS BATTERING WAVES...CAN BE
EXPECTED IN AREAS OF ONSHORE FLOW WITHIN THE HURRICANE WARNING AREA.

SWELLS FROM HANNA ARE EXPECTED TO INCREASE THE RISK OF DANGEROUS RIP
CURRENTS ALONG PORTIONS OF THE SOUTHEASTERN UNITED STATES COAST
DURING THE NEXT COUPLE OF DAYS.

REPEATING THE 200 AM AST POSITION...20.1 N...72.5 W. MOVEMENT...
DRIFTING SOUTHWARD. MAXIMUM SUSTAINED WINDS...65 MPH. MINIMUM
CENTRAL PRESSURE...990 MB.

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

$$
FORECASTER STEWART

[Matthew]

ZCZC MIATCDAT3 ALL
TTAA00 KNHC DDHHMM
TROPICAL STORM HANNA DISCUSSION NUMBER 26
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL082008
500 AM EDT WED SEP 03 2008

FIXES FROM AN AIR FORCE RESERVE UNIT RECONNAISSANCE AIRCRAFT
INDICATE HANNA HAS ALMOST COMPLETED A TIGHT CYCLONIC LOOP AND IS
NOW POSSIBLY TURNING SLOWLY NORTHWARD. THE INITIAL INTENSITY WAS
DECREASED TO COME MORE IN LINE WITH THE CENTRAL PRESSURE...WHICH IS
ESTIMATED TO BE 993 MB BASED ON A DROPSONDE REPORT THAT ALSO
MEASURED 25-KT SURFACE WINDS.

THE INITIAL MOTION ESTIMATE IS 360/02. THERE IS NO SIGNIFICANT
CHANGE TO THE PREVIOUS TRACK OR INTENSITY FORECAST REASONINGS.
HANNA IS EXPECTED TO GRADUALLY ACCELERATE NORTHWESTWARD OVER THE
NEXT 72 HOURS AND MAKE LANDFALL OVER THE SOUTHEASTERN UNITED STATES
...POSSIBLY IN THE SOUTH CAROLINA AREA. IT IS WORTH MENTIONING THAT
THE 00Z MODEL RUNS CONTAINED UPPER-AIR DATA FROM DROPSONDES
RELEASED AROUND HANNAFROM THE NOAA GULFSTREAM-IV JET AIRCRAFT...
WHICH USUALLY PRODUCES BETTER TRACK FORECASTS. THE OFFICIAL
FORECAST IS SIMILAR TO THE PREVIOUS TRACK AND IS CLOSE TO THE NHC
MODEL CONSENSUS.

THE INTENSITY FORECAST BASICALLY REMAINS UNCHANGED AND FOLLOWS THE
SHIPS INTENSITY MODEL...WITH HANNA EXPECTED TO REGAIN HURRICANE
STATUS BY 36 HOURS AND CONTINUE TO INTENSIFY UNTIL LANDFALL OCCURS.

FORECAST POSITIONS AND MAX WINDS

INITIAL 03/0900Z 20.2N 72.2W 50 KT
12HR VT 03/1800Z 21.5N 72.8W 55 KT
24HR VT 04/0600Z 23.2N 74.1W 60 KT
36HR VT 04/1800Z 24.8N 76.0W 65 KT
48HR VT 05/0600Z 27.2N 78.1W 75 KT
72HR VT 06/0600Z 33.7N 80.0W 70 KT...INLAND
96HR VT 07/0600Z 42.5N 71.5W 35 KT...EXTRATROPICAL INLAND
120HR VT 08/0600Z 51.0N 55.0W 35 KT...EXTRATROPICAL INLAND

$$
FORECASTER STEWART

NNNN

[Matthew]

ZCZC MIATCDAT3 ALL
TTAA00 KNHC DDHHMM
TROPICAL STORM HANNA DISCUSSION NUMBER 27
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL082008
1100 AM EDT WED SEP 03 2008

THERE HAVE BEEN SOME STRUCTURAL CHANGES WITH HANNA TODAY AS IT
INTERACTS WITH THE UPPER-LEVEL LOW MOVING THROUGH THE NORTHWESTERN
BAHAMAS. THE WIND FIELD HAS EXPANDED IN THE NORTHERN SEMICIRCLE
AND THE LOW-LEVEL CIRCULATION CENTER HAS BECOME LESS WELL DEFINED.
VISIBLE IMAGERY SUGGESTS MULTIPLE LOW-LEVEL SWIRLS COMING OUT OF
THE DEEP CONVECTION TO THE NORTH OF A MEAN CENTER...AND THE
SYSTEM'S CONVECTIVE BANDS ARE WELL REMOVED FROM THE CORE. THE
RECONNAISSANCE MISSION THAT ENDED AROUND 12Z REPORTED SOME SFMR
WINDS OF UP TO 45 KT ABOUT 70 NM FROM THE CENTER...AND THE INITIAL
INTENSITY ESTIMATE REMAINS 50 KT.

BECAUSE THE CENTER IS NOT WELL DEFINED...THE INTIAL MOTION IS HARD
TO GAUGE. MY BEST ESTIMATE IS 360/5...AND THIS COULD BE THE START
OF THE EXPECTED NORTHWESTWARD TURN. THE STEERING FLOW SHOULD
BECOME BETTER DEFINED OVER THE NEXT 24-48 HOURS AS THE UPPER LOW
MOVES WEST-SOUTHWESTWARD AND MID-LEVEL RIDGING BUILDS IN BEHIND THE
LARGE DEEP-LAYER LOW OFF THE UPPER U.S. EAST COAST. MODEL GUIDANCE
RESPONDS TO THIS PATTERN WITH A NORTHWESTWARD ACCELERATION WITH A
RECURVATURE AROUND THE MID-LEVEL RIDGE IN ABOUT THREE DAYS. THE
GUIDANCE HAS BEEN TOO FAST WITH THIS SCENARIO OVER THE PAST COUPLE
OF DAYS...AND GIVEN THE POOR CORE STRUCTURE OF HANNA I AM INCLINED
TO THINK THAT SUBSEQUENT INTERACTION WITH THE UPPER STEERING MAY BE
A LITTLE OVERDONE...AT LEAST INITIALLY. THE OFFICIAL FORECAST IS
IN BEST AGREEMENT WITH THE ECMWF AND UKMET IN TERMS OF SPEED...WITH
THE GFS/HWRF/GFDL SHOWING A MORE VERTICAL SYSTEM MOVING MORE
RAPIDLY. THE GUIDANCE HAS ALSO BEEN TRENDING EASTWARD OVER THE
PAST FEW CYCLES...AND I HAVE SHIFTED THE TRACK SLIGHTLY IN THAT
DIRECTION.

WESTERLY SHEAR AND DRY AIR ASSOCIATED WITH THE UPPER LOW WILL
INHIBIT DEVELOPMENT IN THE SHORT TERM BUT SHOULD DIMINISH OVER THE
NEXT COUPLE OF DAYS...TO BE REPLACED WITH MODERATE SOUTHEASTERLY
SHEAR. THIS PATTERN WOULD PERMIT SOME RE-INTENSIFICATION...BUT
HANNA WILL NEED TO RECREATE AN INNER CORE IN ORDER TO INTENSIFY
SUBSTANTIALLY. THE AVAILABLE GUIDANCE STILL BRINGS HANNA TO
MINIMAL HURRICANE INTENSITY AND THE OFFICIAL FORECAST IS JUST ABOVE
THIS GUIDANCE.


FORECAST POSITIONS AND MAX WINDS

INITIAL 03/1500Z 20.6N 71.8W 50 KT
12HR VT 04/0000Z 21.5N 72.0W 50 KT
24HR VT 04/1200Z 23.4N 73.3W 55 KT
36HR VT 05/0000Z 25.2N 75.2W 60 KT
48HR VT 05/1200Z 27.3N 77.1W 65 KT
72HR VT 06/1200Z 33.0N 79.0W 70 KT
96HR VT 07/1200Z 42.0N 71.0W 35 KT...INLAND EXTRATROPICAL
120HR VT 08/1200Z 47.0N 60.0W 35 KT...EXTRATROPICAL

$$
FORECASTER FRANKLIN

[Matthew]

000
WTNT43 KNHC 032059
TCDAT3
TROPICAL STORM HANNA DISCUSSION NUMBER 28
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL082008
500 PM EDT WED SEP 03 2008

AN ASCAT PASS FROM 14Z REVEALED THAT THE LOW-LEVEL CIRCULATION OF
HANNA WAS BECOMING ELONGATED IN RESPONSE TO THE ASYMMETRIC
DISTRIBUTION OF CONVECTION. IN SPITE OF THIS...DATA FROM THE
RECONNAISSANCE AIRCRAFT INDICATE THAT HANNA IS BECOMING A LITTLE
BETTER ORGANIZED. TROPICAL STORM FORCE WINDS HAVE RETURNED TO THE
SOUTHWEST QUADRANT AND THE PRESSURE HAS FALLEN TO 989 MB. THE
AIRCRAFT DATA CONTINUE TO SUGGEST THAT THE MAXIMUM WINDS ARE ABOUT
50 KT.

A MORE DEFINITIVE NORTHWARD MOTION HAS COMMENCED...WITH THE INITIAL
ESTIMATE BEING 360/10. THE UPPER LOW OFF OF NEW ENGLAND IS
BEGINNING TO MOVE OUT...AND AS IT DOES SO MID-LEVEL RIDGING WILL
BUILD IN BEHIND IT. HANNA SEEMS TO BE FOLLOWING THE CONVECTION
FAIRLY WELL...AND I'VE HAD TO SPEED UP MY PREVIOUS FORECAST A
LITTLE BIT. THE OFFICIAL FORECAST IS IN BEST AGREEMENT WITH A
BLEND OF THE ECMWF AND THE GFS. THE HWRF AND GFDL CONTINUE TO BE
FASTER THAN THE OFFICIAL FORECAST...AND IF HANNA DEVELOPS FASTER
THAN SHOWN BELOW ADDITIONAL TIMING ADJUSTMENTS MAY NEED TO BE MADE.
IT'S WORTH NOTING THAT CONNECTING THE 48 AND 72 HOUR FORECAST POINTS
WITH A STRAIGHT LINE GIVES A MISLEADING UNDERESTIMATE OF THE
THREAT TO THE GEORGIA AND SOUTH CAROLINA COASTS. ONLY A GRADUAL
RIGHT TURN IS EXPECTED AFTER 48 HOURS.

AS THE UPPER LOW IN THE BAHAMAS AND HANNA SEPARATE...THE SOUTHERLY
SHEAR OVER THE CYCLONE WILL TURN SOUTHEASTERLY AND LESSEN. THIS IS
EXPECTED TO PROVIDE A MORE FAVORABLE ENVIRONMENT FOR
STRENGTHENING...ALTHOUGH NONE OF THE OBJECTIVE AIDS SHOWS VERY
MUCH. THE SHIPS AND LGEM BRING THE SYSTEM ONLY TO 60 KT...AND THE
HWRF NOT QUITE THAT HIGH. THE OFFICIAL FORECAST IS IN GOOD
AGREEMENT WITH THE GFDL WHICH BRINGS HANNA TO 70 KT PRIOR TO
LANDFALL.


FORECAST POSITIONS AND MAX WINDS

INITIAL 03/2100Z 21.9N 71.9W 50 KT
12HR VT 04/0600Z 23.2N 72.7W 55 KT
24HR VT 04/1800Z 25.2N 74.5W 60 KT
36HR VT 05/0600Z 27.4N 76.6W 65 KT
48HR VT 05/1800Z 30.0N 78.5W 70 KT
72HR VT 06/1800Z 36.8N 76.9W 50 KT...INLAND
96HR VT 07/1800Z 44.5N 67.0W 35 KT...EXTRATROPICAL
120HR VT 08/1800Z 48.0N 55.0W 35 KT...EXTRATROPICAL

$$
FORECASTER FRANKLIN

[kenl01]

If I have the time tomorrow afternoon, I'll station myself around or near Wilmington,NC to check out this little thing called Hannah. Mostly it should be tropical storm force winds in those areas East of the center, maybe from 50 to 65 mph and gusty along with squalls and locally heavy rains. I don't really think it'll be a big deal. Not too impressed with the satellite presentation, although some slight strengthening is possible tomorrow.

"VERY DRY AIR ASSOCIATED WITH THE UPPER-LEVEL LOW OVER THE
NORTHWESTERN BAHAMAS IS CHOKING OFF CONVECTION NEAR THE CORE OF
HANNA...AND THE CYCLONE HAS A VERY SUBTROPICAL APPEARANCE.
CONVECTION HAS DIMINISHED SUBSTANTIALLY OVER THE PAST 6-12 HOURS
AND THE HIGHEST FLIGHT-LEVEL AND SFMR WINDS HAVE COME DOWN AS WELL.
BASED ON SOME 52 KT SFMR WINDS AROUND 11Z...THE INITIAL INTENSITY
IS LOWERED TO 55 KT.

CONDITIONS ARE NOT CONDUCIVE TO STRENGTHENING RIGHT NOW...WITH
MODERATE SOUTHERLY SHEAR AND POOR THERMODYNAMICS. THE GFS SUGGESTS THAT DRY AIR IS LIKELY TO CONTINUE TO BE AN ISSUE UP TO LANDFALL."


I might just check it out. (I was stationed in Jacksonville,NC during Isabel in 2003)

Ken