WTNT42 KNHC 082100
TCDAT2
TROPICAL STORM GABRIELLE DISCUSSION NUMBER   4
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL072007
500 PM EDT SAT SEP 08 2007
 
AFTER BEING BRIEFLY INVOLVED WITH THE CIRCULATION CENTER THIS
MORNING...THE CONVECTION HAS SPENT MOST OF THE DAY QUITE SEPARATED
FROM THE CENTER...AND THE BAND IN THE NORTHEASTERN QUADRANT HAS
DISSIPATED.  RECENTLY...HOWEVER...THE CIRCULATION CENTER AND THE
REMAINING CONVECTION IN THE NORTHWESTERN QUADRANT ARE IN THE
PROCESS OF BEING REUNITED.  GABRIELLE HAS TAKEN ON MORE OF
THE APPEARANCE OF A SHEARED TROPICAL CYCLONE...AND BOTH AMSU AND
AIRCRAFT DATA SUGGEST THERE IS A WEAK WARM CORE...SO GABRIELLE IS
BEING DESIGNATED AS A TROPICAL STORM ON THIS ADVISORY.  MAXIMUM
WINDS FROM THE AIR FORCE PLANE AT THE FLIGHT-LEVEL OF ABOUT 1000 FT
WERE ONLY 39 KT...EVEN WITHIN THE CONVECTION IN THE NORTHWESTERN
QUADRANT.  GIVEN THOSE DATA AND THE OVERALL LESSENING OF THE
CONVECTIVE DEPTH AND COVERAGE...THE INTENSITY IS LOWERED TO 35 KT. 
THE CURRENT SOUTHEASTERLY SHEAR MIGHT STILL LESSEN TEMPORARILY
TONIGHT...BUT WILL INCREASE FROM THE NORTH TOMORROW.  THAT WINDOW
OF OPPORTUNITY FOR STRENGTHENING IS THE BASIS FOR THE OFFICIAL
FORECAST TO STILL CALL FOR SLIGHT STRENGTHENING.  THE NEW FORECAST
IS LOWERED COMPARED TO THE PREVIOUS ADVISORY...CALLING FOR
GABRIELLE TO REACH ONLY 45 KT NEAR THE COAST OF NORTH
CAROLINA...AND THIS IS CONSISTENT WITH MOST OF THE GUIDANCE. 
LITTLE CHANGE IN STRENGTH IS FORECAST ONCE GABRIELLE TURNS
NORTHEASTWARD AND EVENTUALLY BECOMES EXTRATROPICAL.
 
THE EXPOSED CIRCULATION CENTER IS EASY TO FIND...BUT THE SMALLER
SWIRL THAT APPEARS TO BE THE CENTER ON SATELLITE IMAGERY SEEMS TO
HAVE ROTATED ABOUT A LARGER MEAN CENTER DURING THE DAY.  THE MOTION
OF THE MEAN CENTER IS NORTHWESTWARD AND SLOWER THAN BEFORE...OR
ROUGHLY 320/7.  THE OFFICIAL TRACK FORECAST AND SUPPORTING
REASONING HAVE NOT NOTICEABLY CHANGED...WITH GABRIELLE EXPECTED TO
ROTATE AROUND THE WESTERN ATLANTIC RIDGE AND INTO THE MIDLATITUDE
WESTERLIES DURING THE NEXT COUPLE OF DAYS...PASSING NEAR OR OVER THE
OUTER BANKS OF NORTH CAROLINA ALONG THE WAY IN 24-36 HOURS.  THE
NEW FORECAST ALSO CALLS FOR GABRIELLE TO BE ABSORBED BY A LARGER
SYSTEM OVER THE NORTH ATLANTIC BY 120 HOURS.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      08/2100Z 32.4N  74.7W    35 KT
 12HR VT     09/0600Z 33.2N  75.4W    40 KT
 24HR VT     09/1800Z 34.6N  75.8W    45 KT
 36HR VT     10/0600Z 36.0N  74.8W    45 KT
 48HR VT     10/1800Z 37.6N  72.8W    45 KT
 72HR VT     11/1800Z 41.5N  65.5W    45 KT...BECOMING EXTRATROPICAL
 96HR VT     12/1800Z 46.0N  55.0W    45 KT...EXTRATROPICAL
120HR VT     13/1800Z...ABSORBED BY LARGER EXTRATROPICAL SYSTEM
 
$$
FORECASTER KNABB
 

WTNT42 KNHC 090248
TCDAT2
TROPICAL STORM GABRIELLE DISCUSSION NUMBER   5
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL072007
1100 PM EDT SAT SEP 08 2007
 
THE LOW-LEVEL CENTER OF GABRIELLE HAS DISAPPEARED UNDER A CIRRUS
OVERCAST CAUSED BY A STRONG CONVECTIVE BURST...WHICH INCLUDED A
SUPERCELL THUNDERSTORM WITH A WELL-DEFINED MESOCYCLONE ON THE
MOREHEAD CITY WSR-88D.  THE BURST HAS ENDED FOR NOW...BUT HAS LEFT
A MID-LEVEL CIRCULATION EVIDENT IN THE DOPPLER RADAR DATA.  WHILE
THE RADAR WINDS DO NOT YET SHOW AN OBVIOUS INCREASE IN INTENSITY...
A RECENT QUIKSCAT OVERPASS SHOWED A FEW 40-45 KT WIND VECTORS THAT
WERE POSSIBLY RAIN CONTAMINATED.  THE INITIAL INTENSITY REMAINS 35
KT...AND IT IS POSSIBLE THIS IS A LITTLE CONSERVATIVE.

THE SURFACE CENTER IS DIFFICULT TO LOCATE IN BOTH SATELLITE AND
RADAR IMAGERY...BUT IS ESTIMATED TO BE A LITTLE TO THE EAST OR
SOUTHEAST OF THE MID-LEVEL CENTER.  THIS MAKES THE INITIAL MOTION A
SOMEWHAT UNCERTAIN 325/10.  THERE IS LITTLE CHANGE TO THE TRACK
FORECAST PHILOSOPHY OTHER THAN THE SLIGHTLY MORE WESTERLY POSITION. 
GABRIELLE SHOULD TURN NORTHWARD AROUND THE WESTERN SIDE OF A
DEEP-LAYER RIDGE OVER THE WESTERN ATLANTIC DURING THE NEXT 12-24
HR.  BEYOND THAT TIME...IT SHOULD ACCELERATE NORTHEASTWARD INTO THE
WESTERLIES.

THE CENTER OF GABRIELLE IS PASSING OVER THE GULF STREAM...AND THE
VERTICAL WIND SHEAR THAT WAS AFFECTING THE SYSTEM EARLIER IS
DIMINISHING.  BASED ON THIS...THE INTENSITY FORECAST CALLS FOR SOME
STRENGTHENING BEFORE THE CENTER REACHES THE NORTH CAROLINA COAST. 
GABRIELLE IS FORECAST TO MAINTAIN INTENSITY DURING EXTRATROPICAL
TRANSITION...AND IT SHOULD BE ABSORBED BY A LARGER EXTRATROPICAL
LOW BETWEEN 72-96 HR.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      09/0300Z 33.1N  75.7W    35 KT
 12HR VT     09/1200Z 34.3N  75.9W    40 KT
 24HR VT     10/0000Z 35.8N  75.6W    45 KT...INLAND
 36HR VT     10/1200Z 37.1N  74.0W    45 KT...OVER WATER
 48HR VT     11/0000Z 39.0N  71.0W    45 KT
 72HR VT     12/0000Z 43.0N  62.5W    45 KT...EXTRATROPICAL
 96HR VT     13/0000Z...DISSIPATED
 
$$
FORECASTER BEVEN
 

WTNT42 KNHC 090900
TCDAT2
TROPICAL STORM GABRIELLE DISCUSSION NUMBER   6
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL072007
500 AM EDT SUN SEP 09 2007
 
PEAK 925 MB WINDS FROM THE RECONNAISSANCE AIRCRAFT INVESTIGATING
GABRIELLE WERE 53 KT IN THE CONVECTION IN THE SOUTHWEST QUADRANT.
THIS WOULD SUPPORT AN ADVISORY INTENSITY OF 40 KT. THE LOW-LEVEL
CENTER REMAINS DISPLACED BY 30 NMI OR MORE FROM THE VIGOROUS
MID-LEVEL ROTATION IN THE DEEP CONVECTION TO THE SOUTHWEST OF THE
CENTER.  HOWEVER...ON THE FIX MADE JUST A MOMENT AGO...THE
FLIGHT-LEVEL DATA SUGGESTED THAT A NEW CENTER MIGHT BE FORMING
WITHIN THE CONVECTION. IF THIS TREND CONTINUES...WE WOULD LIKELY
SEE SOME STRENGTHENING...MAKING GABRIELLE A MID-RANGE TROPICAL
STORM AT LANDFALL.

THE INITIAL MOTION IS 340/9. ALTHOUGH A MODEST WESTWARD JUMP IS
POSSIBLE LATER THIS MORNING IF THE CENTER REFORMS...GABRIELLE IS
EXPECTED TO TURN NORTHWARD AS IT MOVES AROUND THE WESTERN SIDE OF A
DEEP-LAYER RIDGE OVER THE WESTERN ATLANTIC LATER TODAY...AND THEN
BE CAUGHT UP IN INCREASING WESTERLIES AFTER THAT. THERE HAS BEEN
LITTLE CHANGE TO THE FORECAST TRACK THROUGH LANDFALL OVER THE OUTER
BANKS...BUT THE FORECAST HAS BEEN ADJUSTED A LITTLE TO THE SOUTH
AFTER RECURVATURE TO ACCOUNT FOR A MORE ZONAL FLOW IN THE GLOBAL
MODEL GUIDANCE.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      09/0900Z 34.0N  76.1W    40 KT
 12HR VT     09/1800Z 35.3N  76.0W    45 KT
 24HR VT     10/0600Z 36.6N  74.8W    45 KT
 36HR VT     10/1800Z 38.0N  72.5W    40 KT
 48HR VT     11/0600Z 39.2N  69.6W    35 KT
 72HR VT     12/0600Z...ABSORBED BY EXTRATROPICAL LOW
 
$$
FORECASTER FRANKLIN/RHOME
 

WTNT42 KNHC 091142
TCDAT2
TROPICAL STORM GABRIELLE SPECIAL DISCUSSION NUMBER   7
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL072007
800 AM EDT SUN SEP 09 2007
 
REPORTS FROM THE AIR FORCE RESERVE UNIT RECONNAISSANCE AIRCRAFT
INDICATE THAT GABRIELLE HAS STRENGTHENED.  THE AIRCRAFT REPORTED A
PEAK FLIGHT-LEVEL WIND OF 61 KT ABOUT 2 NMI SOUTHEAST OF THE
CENTER...WHICH HAS REFORMED WITHIN THE DEEP CONVECTION UNDERNEATH
THE MID-LEVEL ROTATION OBERSERVED OVERNIGHT.  THE FLIGHT-LEVEL WIND
SUPPORTS AN INITIAL INTENSITY OF 45 KT.  WHILE IT IS POSSIBLE THAT
THIS MESOSCALE VORTEX COULD DISSIPATE BEFORE GABRIELLE MAKES
LANDFALL...IT HAS PERSISTED AND BUILT DOWNWARD OVER THE PAST
SEVERAL HOURS AND IT SEEMS PRUDENT TO ASSUME THAT THESE TRENDS
COULD CONTINUE FOR SEVERAL MORE HOURS.  THE FORECAST INTENSITY IS
THEREFORE INCREASED TO 55 KT...ALTHOUGH IT SHOULD BE EMPHASIZED
THAT THE INCREASED WINDS EXTEND ONLY A FEW MILES FROM THE CENTER.

A SLIGHT WESTWARD ADJUSTMENT HAS BEEN MADE TO THE 12 HOUR FORECAST
POINT...AND THE WIND RADII HAVE BEEN ADJUSTED TO REFLECT THE NEW
INTENSITY FORECAST. 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      09/1200Z 34.2N  76.4W    45 KT
 12HR VT     09/1800Z 35.3N  76.3W    55 KT
 24HR VT     10/0600Z 36.6N  74.8W    55 KT
 36HR VT     10/1800Z 38.0N  72.5W    50 KT
 48HR VT     11/0600Z 39.2N  69.6W    40 KT
 72HR VT     12/0600Z...ABSORBED BY EXTRATROPICAL LOW
 
$$
FORECASTER FRANKLIN
 

WTNT42 KNHC 091500
TCDAT2
TROPICAL STORM GABRIELLE DISCUSSION NUMBER   8
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL072007
1100 AM EDT SUN SEP 09 2007
 
GABRIELLE IS A VERY SMALL TROPICAL CYCLONE WITH THE ASSOCIATED
SHOWER AND THUNDERSTORM ACTIVITY CONFINED TO THE SOUTHWESTERN
QUADRANT.  RECENT RADAR IMAGERY INDICATES THAT THE STRONGEST
REFLECTIVITIES ARE NO LONGER WRAPPING AROUND THE SMALL
CIRCULATION... WHICH HAS SEPARATED A LITTLE FROM THE CONVECTION...
PROBABLY DUE TO NORTHERLY WIND SHEAR.  IN ADDITION...VELOCITY DATA
FROM THE RADAR SUGGEST THAT THE WINDS HAVE NOT INCREASED DURING THE
PAST FEW HOURS.  ALTHOUGH THE AIRCRAFT THAT JUST FLEW THROUGH THE
CENTER HAS NOT SAMPLED THE DEEP CONVECTION IN THE SOUTHWESTERN
QUADRANT...IT HAS NOT FOUND ANY WINDS TO SUGGEST THAT GABRIELLE HAS
STRENGTHENED.  SINCE GABRIELLE IS ABOUT TO INTERACT WITH LAND AND
NORTHERLY SHEAR IS INCREASING...THE OFFICIAL INTENSITY FORECAST HAS
BEEN SLIGHTLY LOWERED.
 
THE INITIAL MOTION IS 360/9...AND RADAR IMAGERY HINTS THAT THE TURN
TO THE RIGHT IS BEGINNING.  GABRIELLE IS CURRENTLY MOVING AROUND
THE WESTERN PERIPHERY OF A DEEP-LAYER RIDGE LOCATED OVER THE
WESTERN ATLANTIC.  THE CYCLONE IS EXPECTED TO ACCELERATE
NORTHWESTWARD INTO THE WESTERLIES WITHIN 24 HOURS.  THE TRACK
GUIDANCE IS IN GOOD AGREEMENT WITH THIS SCENARIO AND THE OFFICIAL
TRACK FORECAST IS AN UPDATE OF THE PREVIOUS ADVISORY.  GABRIELLE IS
FORECAST TO BE ABSORBED BY A LARGER EXTRATROPICAL IN ABOUT 72
HOURS.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      09/1500Z 34.7N  76.3W    45 KT
 12HR VT     10/0000Z 35.9N  75.8W    50 KT...NEAR NC COAST
 24HR VT     10/1200Z 37.3N  73.9W    50 KT...OVER ATLANTIC
 36HR VT     11/0000Z 38.5N  71.1W    45 KT
 48HR VT     11/1200Z 39.8N  67.8W    40 KT
 72HR VT     12/1200Z...ABSORBED
 
$$
FORECASTER BROWN/KNABB
 

WTNT42 KNHC 092054
TCDAT2
TROPICAL STORM GABRIELLE DISCUSSION NUMBER   9
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL072007
500 PM EDT SUN SEP 09 2007
 
DROPSONDE AND FLIGHT-LEVEL WIND DATA FROM THE AIR FORCE
RECONNAISSANCE MISSION THAT DEPARTED GABRIELLE JUST PRIOR
TO LANDFALL SUGGESTED THAT THE MAXIMUM WINDS WERE LIKELY 50 KT OVER
WATER SOUTH OF CAPE LOOKOUT.  THE CENTER THEN MADE LANDFALL ALONG
THE CAPE LOOKOUT NATIONAL SEASHORE AT ABOUT 1545 UTC. SINCE THEN
THE NORTHERLY SHEAR HAS TAKEN ITS TOLL ON THE CYCLONE...AND THE
EXPOSED LOW-LEVEL CENTER HAS PROCEEDED NORTHWARD OVER EXTREME
EASTERN NORTH CAROLINA.  HOWEVER...THE HEAVIEST RAINFALL HAS
REMAINED ALONG THE IMMEDIATE COAST WELL TO THE SOUTH OF THE CENTER.

THE INITIAL INTENSITY IS 45 KT.  THE SHEAR IS EXPECTED TO PERSIST
DURING THE NEXT COUPLE OF DAYS AND THE OFFICIAL INTENSITY FORECAST
INDICATES SLIGHT WEAKENING...BUT MAINTAINS GABRIELLE AS A TROPICAL
STORM UNTIL IT IS ABSORBED BY AN EXTRATROPICAL LOW BY 72 HOURS.
HOWEVER...IF CONVECTION DOES NOT RE-DEVELOP NEAR THE CIRCULATION
CENTER DURING THE NEXT 12-24 HOURS...GABRIELLE COULD WEAKEN FASTER
THAN INDICATED BELOW.
 
THE INITIAL MOTION ESTIMATE IS 010/10. THE FORECAST PHILOSOPHY
REMAINS UNCHANGED AND GABRIELLE IS EXPECTED TO TURN NORTHEASTWARD
SOON AS IT MOVES AROUND THE DEEP-LAYER RIDGE OVER THE WESTERN
ATLANTIC AND INTO THE WESTERLIES. THE TRACK GUIDANCE REMAINS
TIGHTLY CLUSTERED AND THE NEW OFFICIAL FORECAST IS CLOSE TO...BUT
SLIGHTLY SOUTH OF...THE PREVIOUS ADVISORY.   
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      09/2100Z 35.7N  76.1W    45 KT...INLAND
 12HR VT     10/0600Z 36.7N  74.9W    40 KT...OVER ATLANTIC
 24HR VT     10/1800Z 37.8N  72.6W    40 KT
 36HR VT     11/0600Z 38.9N  69.4W    40 KT
 48HR VT     11/1800Z 40.3N  65.5W    35 KT
 72HR VT     12/1800Z...ABSORBED BY EXTRATROPICAL LOW
 
$$
FORECASTER BROWN/KNABB
 

WTNT42 KNHC 100232
TCDAT2
TROPICAL STORM GABRIELLE DISCUSSION NUMBER  10
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL072007
1100 PM EDT SUN SEP 09 2007
 
SATELLITE AND WSR-88D RADAR IMAGES SHOW THAT GABRIELLE IS A POORLY
ORGANIZED SYSTEM WITH ANY REMAINING DEEP CONVECTION FAR TO THE
SOUTH OF THE CENTER. THE STORM HAS EMERGED INTO THE ATLANTIC OCEAN
AND WAS FIXED BY AN AIR FORCE RESERVE HURRICANE HUNTER...FINDING 42
KT MAXIMUM FLIGHT LEVEL WINDS AND A CENTRAL PRESSURE OF 1008 MB.
RECENT SURFACE OBSERVATIONS FROM FRISCO PIER SUGGEST THAT 40 KT
REMAINS A GOOD INITIAL INTENSITY. WITH A CONTINUATION OF STRONG
SHEAR AND ONLY ABOUT 24 HOURS OF WARM WATER REMAINING IN THE
STORM'S PATH...SOME WEAKENING SEEMS LIKELY AND IS SHOWN IN THE NHC
OFFICIAL FORECAST. THIS FORECAST ASSUMES THAT THE SYSTEM WILL
REDEVELOP THUNDERSTORMS AS IT MOVES OVER THE WARM GULF STREAM AND
MAINTAIN ITS STATUS AS A TROPICAL CYCLONE. HOWEVER...IF CONVECTION
CONTINUES TO BE SO FAR REMOVED FROM THE CENTER...GABRIELLE COULD
LOSE TROPICAL CHARACTERISTICS BEFORE MERGING WITH AN EXTRATROPICAL
LOW IN A FEW DAYS.
 
THE MOTION HAS TURNED TOWARD THE NORTHEAST TONIGHT AND IS ESTIMATED
NEAR 035/9. GABRIELLE IS EXPECTED TO EVENTUALLY TURN EAST-
NORTHEASTWARD AS IT MOVES AROUND A DEEP-LAYER RIDGE OVER THE
WESTERN ATLANTIC AND INTO THE MIDDLE-LATITUDE WESTERLIES. THE TRACK
GUIDANCE REMAINS TIGHTLY CLUSTERED AND THE NEW OFFICIAL FORECAST IS
ALMOST THE SAME AS THAT OF PREVIOUS ADVISORY. BEYOND 48 HOURS...
THE SYSTEM IS EXPECTED TO BECOME ABSORBED BY A LARGER EXTRATROPICAL
LOW BY MOST OF THE GLOBAL MODELS. HOWEVER... THE GFS DOES SUGGEST
THE POSSIBILITY OF GABRIELLE REMAINING FAR ENOUGH TO THE SOUTH TO
BE SEPARATE FROM THE LARGE EXTRATROPICAL LOW...BUT TO REMAIN A WEAK
SYSTEM.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      10/0300Z 36.3N  75.3W    40 KT
 12HR VT     10/1200Z 37.2N  73.7W    35 KT
 24HR VT     11/0000Z 38.3N  70.8W    35 KT
 36HR VT     11/1200Z 39.5N  67.5W    35 KT
 48HR VT     12/0000Z 41.0N  62.5W    35 KT
 72HR VT     13/0000Z...ABSORBED
 
$$
FORECASTER BLAKE/PASCH
 

WTNT42 KNHC 100840
TCDAT2
TROPICAL DEPRESSION GABRIELLE DISCUSSION NUMBER  11
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL072007
500 AM EDT MON SEP 10 2007
 
SATELLITE IMAGERY COMING OUT OF THE ECLIPSE INDICATES THAT GABRIELLE
REMAINS VOID OF DEEP CONVECTION.  THE LOW-LEVEL CENTER RECENTLY
MOVED JUST NORTH OF BUOY 44014 WHICH REPORTED MAXIMUM WINDS OF 25
KT. BASED ON THIS INFORMATION...GABRIELLE IS DOWNGRADED TO A 30 KT
DEPRESSION.  THE OFFICIAL TRACK FORECAST ESSENTIALLY TAKES
GABRIELLE ALONG THE NORTH WALL OF THE GULF STREAM.  SINCE ANY
DEVIATION TO THE SOUTH WOULD BRING THE SYSTEM OVER WARMER
WATERS...INTERMITTENT BURSTS OF CONVECTION CANNOT BE RULED OUT. 
ANY CONVECTION WHICH DOES FORM WOULD LIKELY BE QUICKLY SHEARED OFF
AS THE SYSTEM HAS BECOME EMBEDDED IN STRONG ZONAL FLOW. THE
OFFICIAL FORECAST MAINTAINS GABRIELLE AS A 30 KT DEPRESSION FOR 2
DAYS AT WHICH TIME IT IS EXPECTED TO MERGE WITH A STRONGER
EXTRATROPICAL LOW.  HOWEVER...IF CONVECTION DOES NOT REFORM
SOON...GABRIELLE COULD BECOME A REMNANT LOW LATER TODAY. 

THE INITIAL MOTION ESTIMATE IS 045/10.  THERE HAS BEEN NO
SIGNIFICANT CHANGE TO THE TRACK FORECAST REASONING OR GUIDANCE AND
THE OFFICIAL FORECAST IS MERELY AN UPDATE OF THE PREVIOUS ONE. 
GABRIELLE IS EXPECTED TO ACCELERATE EAST-NORTHEASTWARD OVER THE
NEXT TWO DAYS AHEAD OF A MID-LATITUDE TROUGH PROGRESSING OVER THE
EASTERN UNITED STATES.  
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      10/0900Z 37.0N  74.4W    30 KT
 12HR VT     10/1800Z 37.8N  72.5W    30 KT
 24HR VT     11/0600Z 38.9N  69.4W    30 KT
 36HR VT     11/1800Z 40.4N  65.3W    30 KT
 48HR VT     12/0600Z 42.3N  60.0W    30 KT
 72HR VT     13/0600Z...ABSORBED
 
$$
FORECASTER RHOME
 

WTNT42 KNHC 101440
TCDAT2
TROPICAL DEPRESSION GABRIELLE DISCUSSION NUMBER  12
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL072007
1100 AM EDT MON SEP 10 2007
 
DURING THE PAST SEVERAL HOURS A SMALL AREA OF THUNDERSTORMS HAS
DEVELOPED ABOUT 75 NM SOUTHEAST OF THE CENTER.  HOWEVER....
NORTHWESTERLY SHEAR HAS NOT ALLOWED THIS THUNDERSTORM ACTIVITY TO
ACQUIRE MUCH CURVATURE.  A 1026 UTC QUIKSCAT OVERPASS INDICATED
THAT THE MAXIMUM WINDS WERE 25-30 KT AND THE INITIAL INTENSITY WILL
REMAIN 30 KT. 

GABRIELLE HAS BEEN MOVING ALMOST DUE EASTWARD DURING THE PAST FEW
HOURS...BUT A LONGER-TERM MOTION YIELDS AN INITIAL MOTION ESTIMATE
OF 070/11.  THE TRACK FORECAST IS VERY SIMILAR TO THE PREVIOUS
ADVISORY...BUT IS ADJUSTED SLIGHTLY SOUTHWARD MAINLY DUE TO THE MORE
EASTWARD INITIAL MOTION.  THE NEW TRACK IS ALONG THE SOUTH SIDE
OF THE MODEL ENVELOPE AND CLOSE TO THE GFS TRACK.

GABRIELLE IS FORECAST TO REMAIN IN A HOSTILE ENVIRONMENT WITH STRONG
NORTHWESTERLY SHEAR AND GRADUALLY DECREASING SSTS.  THE OFFICIAL
FORECAST WILL MAINTAIN THE CYCLONE AS A 30 KT DEPRESSION UNTIL IT
MERGES WITH A LARGER EXTRATROPICAL LOW IN ABOUT 48 HOURS.
HOWEVER...IF THE DEPRESSION IS NOT ABLE TO GENERATE MORE ORGANIZED
CONVECTION THAN CURRENTLY OBSERVED...IT MAY NOT SURVIVE AS A
TROPICAL CYCLONE FOR THAT LONG.

FORECAST POSITIONS AND MAX WINDS
 
INITIAL      10/1500Z 37.1N  73.0W    30 KT
 12HR VT     11/0000Z 37.9N  71.1W    30 KT
 24HR VT     11/1200Z 39.3N  67.5W    30 KT
 36HR VT     12/0000Z 41.1N  62.9W    30 KT
 48HR VT     12/1200Z...ABSORBED BY EXTRATROPICAL LOW
 
$$
FORECASTER BROWN
 

WTNT42 KNHC 102032
TCDAT2
TROPICAL DEPRESSION GABRIELLE DISCUSSION NUMBER  13
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL072007
500 PM EDT MON SEP 10 2007
 
A FEW THUNDERSTORMS HAVE DEVELOPED A LITTLE CLOSER TO THE CENTER OF
GABRIELLE THIS AFTERNOON.  HOWEVER...THE OVERALL CIRCULATION APPEARS
TO BE LESS DEFINED THAN IT WAS EARLIER TODAY.  THE INITIAL
INTENSITY WILL REMAIN 30 KT...WHICH COULD BE A LITTLE GENEROUS.
GABRIELLE HAS ACCELERATED AND CONTINUES TO MOVE JUST NORTH OF DUE
EAST...WITH AN INITIAL MOTION ESTIMATE OF 075/15 KT. THE TRACK
FORECAST WAS AGAIN ADJUSTED SOUTHWARD OF THE PREVIOUS ADVISORY
MAINLY DUE TO THE MORE EASTWARD INITIAL MOTION.  THE NEW TRACK IS
IN GOOD AGREEMENT WITH THE GFS AND UKMET MODELS.  THE GLOBAL MODELS
AGREE THAT GABRIELLE WILL BE ABSORBED WITHIN A FRONTAL ZONE OVER
THE NORTH ATLANTIC IN 36-48 HOURS.
 
THE INTENSITY FORECAST KEEPS GABRIELLE AS A 30 KT TROPICAL
DEPRESSION UNTIL IT IS ABSORBED. HOWEVER...IF THE DEPRESSION IS NOT
ABLE TO GENERATE MORE ORGANIZED CONVECTION THAN CURRENTLY
OBSERVED...IT MAY NOT SURVIVE AS A TROPICAL CYCLONE FOR THAT LONG.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      10/2100Z 37.6N  71.0W    30 KT
 12HR VT     11/0600Z 38.1N  68.4W    30 KT
 24HR VT     11/1800Z 39.4N  64.2W    30 KT
 36HR VT     12/0600Z 41.4N  59.0W    30 KT
 48HR VT     12/1800Z...ABSORBED BY FRONTAL ZONE
 
$$
FORECASTER BROWN
 

WTNT42 KNHC 110848
TCDAT2
TROPICAL DEPRESSION GABRIELLE DISCUSSION NUMBER  15
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL072007
500 AM EDT TUE SEP 11 2007
 
IN ADDITION TO THE REGULARLY SCHEDULED ECLIPSE PERIOD FOR
GOES-EAST...GEOSTATIONARY SATELLITE IMAGERY HAS BEEN UNAVAILABLE
FOR A LONGER PERIOD OF TIME TONIGHT DUE TO A LUNAR SHADOW.  THIS
EVENT OCCURS ABOUT TWICE PER YEAR WHEN THE MOON IS POSITIONED
BETWEEN THE SATELLITE AND THE SUN.  LUCKILY...A VERY TIMELY TRMM
PASS AT 0611 UTC HELPED LOCATE THE CENTER AND INDICATED DEEP
CONVECTION REMAINS SOUTHEAST OF THE LOW-LEVEL CIRCULATION. 
ADDITIONALLY...GABRIELLE IS JUST BECOMING VISIBLE IN THE OUTER
FRINGES OF METSAT-9 IMAGERY...WHICH ALSO SHOWS DEEP CONVECTION TO
THE SOUTHEAST OF THE CIRCULATION CENTER.  THE INITIAL INTENSITY IS
THUS HELD AT 30 KT FOR THIS ADVISORY.  GABRIELLE IS CURRENTLY
MOVING RIGHT ALONG THE NORTH WALL OF THE GULF STREAM AND IS
FORECAST TO MOVE OVER A WARM CORE EDDY IN A FEW HOURS. THEREFORE...
GABRIELLE MIGHT BE ABLE TO GENERATE DEEP CONVECTION...ALBEIT
LIMITED...FOR ANOTHER 12-24 HOURS.  HOWEVER...SHARPLY COOLER WATERS
TO THE NORTH AND A CONTINUATION OF STRONG NORTHERLY SHEAR SHOULD
KEEP CONVECTION PRIMARILY CONFINED SOUTH OF THE CENTER AND PREVENT
SIGNIFICANT STRENGTHENING.  GABRIELLE IS EXPECTED TO MERGE WITH A
FRONTAL ZONE IN 24-36 HOURS. 

THE 0611 UTC TRMM PASS INDICATES THAT GABRIELLE IS MOVING A LITTLE
TO THE NORTH OF THE PREVIOUS FORECAST TRACK WITH AN INITIAL MOTION
ESTIMATE OF 065/18.  THE OFFICIAL FORECAST IS NUDGED A LITTLE
TOWARD THE NORTH BASED ON THIS DATA. 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      11/0900Z 39.0N  66.8W    30 KT
 12HR VT     11/1800Z 40.2N  63.6W    30 KT
 24HR VT     12/0600Z 42.1N  58.5W    30 KT
 36HR VT     12/1800Z...ABSORBED
 
$$
FORECASTER RHOME
 

WTNT42 KNHC 111444
TCDAT2
TROPICAL DEPRESSION GABRIELLE DISCUSSION NUMBER  16
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL072007
1100 AM EDT TUE SEP 11 2007

THUNDERSTORM ACTIVITY CONTINUES OVER THE SOUTHEASTERN PORTION OF
GABRIELLE.  HOWEVER...A 1000 UTC QUIKSCAT OVERPASS INDICATES THAT
THE CIRCULATION HAS BECOME ILL-DEFINED AND ELONGATED SOUTHEAST TO
NORTHWEST. IN FACT...THE VORTICITY CENTER THAT HAS BEEN TRACKED IN
SATELLITE IMAGERY OVERNIGHT IS LOCATED AT THE SOUTHEASTERN END OF A
TROUGH CHARACTERIZED BY LIGHT AND VARIABLE WINDS. SINCE A
WELL-DEFINED SURFACE CIRCULATION NO LONGER EXISTS...THIS SYSTEM NO
LONGER QUALIFIES AS A TROPICAL CYCLONE AND THIS WILL BE THE LAST
ADVISORY ISSUED ON GABRIELLE.  AN ILL-DEFINED REMNANT LOW COULD
PERSIST FOR A FEW MORE HOURS BUT SHOULD DISSIPATE IN THE INCREASING
SOUTHWESTERLY FLOW AHEAD OF A DEVELOPING EXTRATROPICAL LOW OVER
EASTERN NORTH AMERICA.    
 
ADDITIONAL INFORMATION ON THIS SYSTEM CAN BE FOUND IN HIGH SEAS
FORECASTS ISSUED BY THE NATIONAL WEATHER SERVICE...UNDER AWIPS
HEADER NFDHSFAT1 AND WMO HEADER FZNT01 KWBC.
  
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      11/1500Z 39.6N  65.3W    30 KT...DISSIPATING
 12HR VT     12/0000Z 40.9N  61.4W    25 KT...REMNANT LOW
 24HR VT     12/1200Z...DISSIPATED
 
$$
FORECASTER BROWN
 

