WTNT44 KNHC 210232
TCDAT4
TROPICAL DEPRESSION NINETEEN DISCUSSION NUMBER   1
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL192010
1100 PM EDT WED OCT 20 2010
 
SATELLITE IMAGES INDICATE THAT THE CENTER OF THE LOW PRESSURE SYSTEM
OVER THE NORTHWESTERN CARIBBEAN SEA IS NOW LOCATED CLOSER TO THE
MAIN MASS OF DEEP CONVECTION THAN IT WAS EARLIER TODAY.  THE OVERALL
CLOUD PATTERN HAS BECOME SLIGHTLY BETTER ORGANIZED...RESULTING IN
DVORAK DATA T-NUMBERS OF 1.5 FROM BOTH TAFB AND SAB.  DEEP
CONVECTION HAS ALSO BEEN ON THE INCREASE DURING THE LAST SEVERAL
HOURS.  BASED PRIMARILY ON THE FACT THAT THE CIRCULATION CENTER IS
NOW MORE INVOLVED WITH THE DEEP CONVECTION...THE SYSTEM IS BEING
DESIGNATED AS A TROPICAL CYCLONE AT THIS TIME.  RECONNAISSANCE DATA
FROM EARLIER TODAY INDICATED AN INTENSITY NEAR 30 KT...AND IT IS
ASSUMED THAT THERE HAS BEEN LITTLE CHANGE IN STRENGTH SINCE THE
TIME OF THOSE OBSERVATIONS.
 
SINCE THE CENTER APPEARS TO HAVE REFORMED DURING THE LAST FEW
HOURS...THE INITIAL MOTION ESTIMATE IS AN UNCERTAIN 100/02.  THE
CYCLONE IS CURRENTLY LOCATED IN A COL REGION AT THE BASE OF A
MID-LEVEL TROUGH OVER THE EASTERN UNITED STATES AND TO THE WEST OF
A SUBTROPICAL RIDGE OVER THE CENTRAL ATLANTIC.  GLOBAL MODELS BUILD
THE SUBTROPICAL RIDGE TO NORTH OF THE TROPICAL CYCLONE AS THE TROUGH
LIFTS OUT OF THE REGION AFTER ABOUT 36 HOURS.  THE MAJORITY OF THE
TRACK GUIDANCE SHOWS A SLOW LOOPING MOTION TOWARD THE SOUTHEAST...
SOUTH...AND THEN SOUTHWEST DURING THE NEXT DAY OR TWO.  AFTER
THAT...A WESTWARD TO WEST-NORTHWESTWARD MOTION WITH SOME INCREASE
IN FORWARD SPEED IS INDICATED DUE TO THE BUILDING RIDGE TO THE
NORTH.  THE TRACK GUIDANCE IS IN GOOD AGREEMENT ON THIS SCENARIO...
EXCEPT FOR THE HWRF WHICH TAKES THE CYCLONE TOWARD THE YUCATAN
CHANNEL AND THEN TURNS IT NORTHEASTWARD TOWARD FLORIDA.  ALTHOUGH
THE LATTER SOLUTION CANNOT BE COMPLETELY DISCOUNTED...THE
OFFICIAL NHC TRACK FORECAST LEANS TOWARDS A CONSENSUS OF THE OTHER
DYNAMICAL MODELS.
 
UW-CIMSS ANALYSES INDICATE THAT THE DEPRESSION IS BEING AFFECTED BY
MODERATE SOUTHWESTERLY SHEAR ASSOCIATED WITH THE EASTERN UNITED
STATES TROUGH.  AS THIS FEATURE LIFTS OUT OF THE AREA IN ABOUT 36
HOURS...THE SHIPS MODEL OUTPUT INDICATES A REDUCTION IN THE SHEAR IN
A DAY OR TWO WHICH SHOULD FAVOR GRADUAL INTENSIFICATION OVER THE
WARM WATERS OF THE NORTHWESTERN CARIBBEAN.  LATER IN THE FORECAST
PERIOD...THE INTENSITY FORECAST IS COMPLICATED BY UNCERTAINTIES IN
THE FUTURE INTERACTION WITH LAND.  THE OFFICIAL FORECAST IS IN
REASONABLE AGREEMENT WITH THE INTENSITY MODEL CONSENSUS AND THE
STATISTICAL-DYNAMICAL LGEM GUIDANCE.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      21/0300Z 17.5N  81.1W    30 KT
 12HR VT     21/1200Z 17.1N  80.7W    30 KT
 24HR VT     22/0000Z 16.8N  80.7W    30 KT
 36HR VT     22/1200Z 16.4N  81.1W    35 KT
 48HR VT     23/0000Z 16.3N  81.7W    40 KT
 72HR VT     24/0000Z 16.6N  84.1W    50 KT
 96HR VT     25/0000Z 18.0N  87.5W    55 KT
120HR VT     26/0000Z 19.5N  90.0W    30 KT
 
$$
FORECASTER KIMBERLAIN/PASCH
 

WTNT44 KNHC 210842
TCDAT4
TROPICAL DEPRESSION NINETEEN DISCUSSION NUMBER   2
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL192010
500 AM EDT THU OCT 21 2010
 
THE THUNDERSTORM ACTIVITY HAS INCREASED DURING THE PAST SEVERAL
HOURS AND THERE HAS BEEN SOME INCREASE IN ORGANIZATION. ALTHOUGH
THE SHEAR SEEMS TO BE RELAXING AS INDICATED BY MOTION OF THE HIGH
CLOUDS...THE CENTER IS STILL LOCATED ON THE WESTERN PORTION OF A
CYCLONICALLY CURVED CONVECTIVE BAND. SATELLITE INTENSITY ESTIMATES
FROM BOTH TAFB AND SAB ARE 2.5 ON THE DVORAK SCALE...INDICATING
THAT THE DEPRESSION COULD BE A TROPICAL STORM. HOWEVER...AN AIR
FORCE PLANE WILL BE IN THE AREA IN A FEW HOURS...AND I WOULD RATHER
WAIT FOR THE RECONNAISSANCE DATA TO UPGRADE THE SYSTEM TO A
TROPICAL STORM. HAVING SAID THAT...MOST OF THE GLOBAL MODELS ARE
SHOWING THE DEVELOPMENT OF AN UPPER-LEVEL ANTICYCLONE NEAR OR OVER
THE DEPRESSION IN A DAY OR SO...AND A TRACK A LITTLE BIT MORE
DISTANT FROM THE HIGH TERRAIN OF CENTRAL AMERICA. THESE CONDITIONS
AND THE PREVAILING WARM OCEAN WOULD BE FAVORABLE FOR
INTENSIFICATION. THE OFFICIAL FORECAST CALLS FOR A LITTLE MORE
STRENGTHENING THAN INDICATED IN THE PREVIOUS ADVISORY BUT NOT AS
AGGRESSIVE AS THE GFDL AND THE HWRF. THE DEPRESSION IS FORECAST TO
BECOME A HURRICANE IN THE NORTHWESTERN CARIBBEAN AS INDICATED BY
THE INTENSITY MODEL CONSENSUS.
 
 
THE DEPRESSION HAS BEEN MOVING SLOWLY TOWARD THE SOUTHEAST OR 135
DEGREES AT 3 KNOTS...EMBEDDED IN VERY LIGHT STEERING CURRENTS.
LITTLE MOTION IS ANTICIPATED DURING THE NEXT DAY OR SO.
THEREAFTER...ALL GLOBAL MODELS LIFT OUT THE CURRENT TROUGH OVER THE
WESTERN ATLANTIC AND REPLACE IT WITH A SUBTROPICAL RIDGE. THIS NEW
STEERING PATTERN WOULD FORCE THE CYCLONE ON A WEST TO WEST-NORTHWEST
TRACK ACROSS THE NORTHWESTERN CARIBBEAN SEA AND THE YUCATAN
PENINSULA. THE OFFICIAL TRACK FORECAST HAS SHIFTED A LITTLE BIT TO
THE NORTH...AND IS HEAVILY BASED ON THE GFS...THE UK MODELS AND
CONTINUITY. I HAVE LESS CONFIDENCE IN THE FORECAST BEYOND 72 HOURS
BECAUSE THE GFDL...THE HWRF AND THE ECMWF TURN THE CYCLONE TOWARD
THE NORTH OVER THE YUCATAN CHANNEL AND THE SOUTHEASTERN GULF OF
MEXICO. I WOULD NOT BE SURPRISED IF THE TRACK HAS TO BE ADJUSTED
NORTHWARD LATER ON.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      21/0900Z 17.0N  80.7W    30 KT
 12HR VT     21/1800Z 16.8N  80.7W    40 KT
 24HR VT     22/0600Z 16.5N  81.0W    45 KT
 36HR VT     22/1800Z 16.5N  81.5W    55 KT
 48HR VT     23/0600Z 16.5N  82.0W    65 KT
 72HR VT     24/0600Z 17.5N  84.5W    65 KT
 96HR VT     25/0600Z 19.0N  88.0W    40 KT...INLAND
120HR VT     26/0600Z 21.0N  90.0W    30 KT...INLAND
 
$$
FORECASTER AVILA
 

