WTNT45 KNHC 112034
TCDAT5
TROPICAL DEPRESSION FIFTEEN DISCUSSION NUMBER   1
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL152007
500 PM EDT THU OCT 11 2007
 
THE AREA OF LOW PRESSURE IN THE CENTRAL ATLANTIC EAST OF BERMUDA HAS
BEEN MAINTAINING STEADY DEEP CONVECTION NEAR THE CENTER FOR ABOUT
12 HOURS OR SO...AND DVORAK CLASSIFICATIONS FROM TAFB AND SAB AT
18Z HAVE RISEN TO T1.5.  ON THIS BASIS...ADVISORIES ARE INITIATED ON
TROPICAL DEPRESSION FIFTEEN.  AN ASCAT PASS NEAR 14Z SUGGESTS THAT
MAXIMUM WINDS ARE NEAR 30 KT.
 
THE INITIAL MOTION IS 075/14.  THE CYCLONE IS LOCATED TO THE EAST OF
AN UPPER LOW THAT IS PRODUCING STRONG SOUTHWESTERLY FLOW OVER THE
CENTER.  GLOBAL MODELS SUGGEST THAT THE SOUTHWESTERLY FLOW WILL BE
REPLACED BY EVEN STRONGER NORTHERLIES OVER THE NEXT 24-36 HOURS. 
IN THIS STRONG SHEAR ENVIRONMENT...THE MOTION OF THE CYCLONE WILL
DEPEND ON HOW MUCH CONNECTION THE CENTER MAINTAINS WITH THE FLOW
ALOFT.  THE 12Z RUNS OF THE GLOBAL MODELS SEEM TO HAVE ALREADY
SEPARATED THE CENTER FROM THE DEEP CONVECTION...WHICH OF COURSE
HASN'T HAPPENED YET.  AS A RESULT...MY FORECAST TAKES THE CYCLONE A
LITTLE FARTHER EAST THAN MOST OF THE OBJECTIVE GUIDANCE.  BEFORE
TOO LONG...HOWEVER...THE SHEAR SHOULD PREVAIL...LEAVING THE
LOW-LEVEL CIRCULATION BEHIND TO MEANDER UNTIL THE NEXT FRONTAL
SYSTEM ARRIVES IN THE AREA IN ABOUT TWO DAYS.

WITH STRONG SHEAR FORECAST TO PERSIST OVER THE CYCLONE...LITTLE OR
NO STRENGTHENING IS EXPECTED.  THE OFFICICAL FORECAST IS IN GOOD
AGREEMENT WITH THE SHIPS AND HWRF GUIDANCE.  THE GFDL DOES BRING
THE DEPRESSION TO STORM STRENGTH...BUT THERE IS ONLY A VERY SHORT
WINDOW OF OPPORTUNITY FOR THIS TO OCCUR. 

IT IS POSSIBLE THAT SOME OF THE LOW-LEVEL VORTICITY FROM KAREN'S
REMNANTS HAS PLAYED A ROLE IN THE GENESIS OF THIS CYCLONE. 
HOWEVER...THE EVIDENCE IS NOT STRONG ENOUGH TO ATTACH THAT NAME TO
THIS SYSTEM.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      11/2100Z 30.1N  50.5W    30 KT
 12HR VT     12/0600Z 30.1N  49.0W    30 KT
 24HR VT     12/1800Z 30.0N  48.0W    30 KT
 36HR VT     13/0600Z 30.0N  48.0W    25 KT...REMNANT LOW
 48HR VT     13/1800Z 31.0N  47.5W    25 KT...REMNANT LOW
 72HR VT     14/1800Z...DISSIPATED
 
$$
FORECASTER FRANKLIN
 

WTNT45 KNHC 120234
TCDAT5
TROPICAL DEPRESSION FIFTEEN DISCUSSION NUMBER   2
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL152007
1100 PM EDT THU OCT 11 2007
 
THE OVERALL CLOUD PATTERN OF THE DEPRESSION HAS CHANGED VERY LITTLE 
THIS EVENING. DVORAK INTENSITY ESTIMATES FROM SAB AND TAFB ARE 25
AND 30 KT RESPECTIVELY AND THE INITIAL INTENSITY WILL REMAIN 30 KT.
THE DEPRESSION IS ONCE AGAIN IN THE QUIKSCAT GAP...BUT AMSU AND SSMI
MICROWAVE OVERPASSES HAVE BEEN HELPFUL IN FINDING THE CENTER OF THE
CYCLONE...WHICH IS LOCATED JUST SOUTHWEST OF THE DEEP CONVECTION. 
BASED ON THE MICROWAVE AND SATELLITE FIXES...THE DEPRESSION HAS
BEEN DECELERATING DURING THE PAST FEW HOURS AND THE INITIAL MOTION
ESTIMATE IS 090/8 KT.    
 
AN UPPER LEVEL TROUGH SEEN IN WATER VAPOR IMAGERY IS APPROACHING THE
CYCLONE FROM THE WEST.  AS THIS TROUGH MOVES BY THE DEPRESSION
TONIGHT....THE STRONG SOUTHWESTERLY UPPER-LEVEL WINDS THAT HAVE
BEEN PLAGUING THE SYSTEM WILL BE REPLACED BY STRONGER NORTHERLIES. 
THEREFORE...LITTLE OR NO STRENGTHENING IS EXPECTED AND THE 
DEPRESSION IS FORECAST TO BECOME A REMNANT LOW IN ABOUT 36 HOURS...
IF NOT SOONER.

THE TRACK FORECAST REASONING REMAINS UNCHANGED FROM THE PREVIOUS
ADVISORY.  AS THE DEPRESSION BECOMES A MORE SHALLOW SYSTEM...IT IS
EXPECTED TO CONTINUE TO DECELERATE AND MEANDER UNTIL A COLD FRONT
APPROACHES THE CENTRAL ATLANTIC IN ABOUT 48 HOURS. THE NEW OFFICIAL
FORECAST IS A LITTLE SLOWER AND WEST OF THE PREVIOUS TRACK....CLOSE
TO THE 18Z UKMET SOLUTION.
  
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      12/0300Z 30.0N  49.7W    30 KT
 12HR VT     12/1200Z 30.0N  48.9W    30 KT
 24HR VT     13/0000Z 30.1N  48.4W    25 KT
 36HR VT     13/1200Z 30.4N  48.2W    25 KT...REMNANT LOW
 48HR VT     14/0000Z 31.0N  48.2W    25 KT...REMNANT LOW
 72HR VT     15/0000Z...DISSIPATED
 
$$
FORECASTER BROWN
 

WTNT45 KNHC 120831
TCDAT5
TROPICAL DEPRESSION FIFTEEN DISCUSSION NUMBER   3
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL152007
500 AM EDT FRI OCT 12 2007
 
SATELLITE IMAGERY THIS MORNING INDICATES THAT TROPICAL DEPRESSION
FIFTEEN HAS CHANGED LITTLE IN ORGANIZATION...WITH THE CENTER A
LITTLE LESS INVOLVED WITH THE CONVECTION THAN 6 HR AGO.  SATELLITE
INTENSITY ESTIMATES ARE 30 KT FROM TAFB AND 25 KT FROM SAB...SO THE
INITIAL INTENSITY REMAINS 30 KT.  THE CIRRUS OUTFLOW IS FAIR TO THE
EAST AND ALMOST NON-EXISTENT ELSEWHERE.

THE INITIAL MOTION IS A SOMEWHAT UNCERTAIN 090/3.  THE DEPRESSION IS
EMBEDDED IN THE LOW/MID-LEVEL SUBTROPICAL RIDGE...A CONDITION THAT
IS FORECAST TO CAUSE 24 HR OR SO OF SLOW MOTION.  AFTER THAT...A
LOW/MID-LEVEL TROUGH OR FRONTAL SYSTEM APPROACHING FROM THE WEST
WILL WEAKEN THE RIDGE AND STEER THE CYCLONE...OR ITS REMAINS...
NORTHWARD OR NORTH-NORTHEASTWARD.  THE NEW FORECAST TRACK IS AGAIN
SHIFTED TO THE WEST OF THE PREVIOUS TRACK BASED ON THE INITIAL
POSITION AND MOTION...AND IT LIES NEAR THE RIGHT EDGE OF THE
GUIDANCE ENVELOPS
 
THE DEPRESSION IS CURRENTLY UNDER THE AXIS OF AN UPPER-LEVEL
TROUGH...WHICH HAS REDUCED THE VERTICAL WIND SHEAR FOR THE MOMENT. 
HOWEVER...ALL DYNAMICAL GUIDANCE FORECASTS THE CYCLONE TO BE
BLASTED BY 40-50 KT OF UPPER-LEVEL NORTHERLY FLOW WITHIN 12-24 HR. 
THIS SHOULD CAUSE THE DEPRESSION TO WEAKEN TO A REMNANT LOW IN
24-36 HR...AND THIS COULD OCCUR EARLIER.  SOME OF THE DYNAMICAL
MODELS FORECAST A REMNANT CIRCULATION TO SURVIVE 48 HR...SO THE
OFFICIAL FORECAST CONTINUES TO INDICATE A REMNANT LOW TO THAT TIME. 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      12/0900Z 30.0N  49.4W    30 KT
 12HR VT     12/1800Z 30.1N  49.1W    30 KT
 24HR VT     13/0600Z 30.4N  48.9W    25 KT
 36HR VT     13/1800Z 30.9N  48.9W    25 KT...REMNANT LOW
 48HR VT     14/0600Z 32.3N  48.6W    25 KT...REMNANT LOW
 72HR VT     15/0600Z...DISSIPATED
 
$$
FORECASTER BEVEN
 

WTNT45 KNHC 121428
TCDAT5
TROPICAL DEPRESSION FIFTEEN DISCUSSION NUMBER   4
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL152007
1100 AM EDT FRI OCT 12 2007
 
THE LOW LEVEL CIRCULATION IS BECOMING LESS DISTINCT AND DEEP
CONVECTION IS LIMITED TO A FEW CELLS OVER THE NORTHERN SEMICIRCLE.
CONSEQUENTLY...DVORAK-T-NUMBERS HAVE DECREASED. THE INITIAL
INTENSITY HAS BEEN LOWERED TO 25 KNOTS AND BECAUSE THE SHEAR IS
FORECAST TO INCREASE SIGNIFICANTLY...THE DEPRESSION SHOULD BECOME A
REMNANT LOW IN ABOUT 24 HOURS OR SOONER. 

THE DEPRESSION IS DRIFTING EASTWARD ABOUT 2 KNOTS. STEERING CURRENTS
ARE EXPECTED TO REMAIN VERY LIGHT AND NO SIGNIFICANT MOTION IS
ANTICIPATED UNTIL DISSIPATION.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      12/1500Z 30.1N  49.1W    25 KT
 12HR VT     13/0000Z 30.2N  48.9W    25 KT
 24HR VT     13/1200Z 30.5N  49.0W    20 KT...REMNANT LOW
 36HR VT     14/0000Z...DISSIPATED

$$
FORECASTER AVILA
 

WTNT45 KNHC 122030
TCDAT5
TROPICAL DEPRESSION FIFTEEN DISCUSSION NUMBER   5
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL152007
500 PM EDT FRI OCT 12 2007
 
THE DEPRESSION HAS BECOME A TIGHT SWIRL OF LOW CLOUDS DEVOID OF DEEP
CONVECTION. IN FACT...IT APPEARS THAT IT IS RAPIDLY WEAKENING TO A
REMNANT LOW. THE SHEAR IS FORECAST TO INCREASE SIGNIFICANTLY...
THEREFORE REGENERATION IS NOT ANTICIPATED. THE SYSTEM COULD STILL
PRODUCE INTERMITTENT BURST OF CONVECTION BEFORE DISSIPATION.
 
THE DEPRESSION HAS BEEN MEANDERING AND ONLY A SMALL NORTHWARD DRIFT
IS ANTICIPATED DURING THE NEXT 12 TO 24 HOURS.
 
THIS WILL BE THE LAST ADVISORY OF THIS SYSTEM. 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      12/2100Z 30.8N  49.5W    25 KT
 12HR VT     13/0600Z 31.5N  49.5W    20 KT...REMNANT LOW
 24HR VT     13/1800Z 32.5N  49.5W    20 KT...REMNANT LOW
 36HR VT     14/0600Z...DISSIPATED
 
$$
FORECASTER AVILA
 

