[Tropical] Tropical Cyclone Discussion

[EMWIN Server]

WTNT45 KNHC 041443
TCDAT5

TROPICAL STORM EMILY DISCUSSION NUMBER  12
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL052011
1100 AM EDT THU AUG 04 2011

SATELLITE IMAGES REVEAL THAT THE CLOUD PATTERN IS A LITTLE BETTER
ORGANIZED THAN YESTERDAY WHEN THERE WAS AN EXPOSED LOW LEVEL
CENTER. TODAY THE CENTER IS WELL EMBEDDED IN THE CONVECTION WITH
CYCLONICALLY CURVED CONVECTIVE BANDS...A POSSIBLE CENTRAL DENSE
OVERCAST...AND MORE SIGNIFICANTLY...THE OUTFLOW HAS BECOME
ESTABLISHED IN ALL QUADRANTS. HOWEVER...DATA FROM THE
RECONNAISSANCE AIRCRAFT EARLIER THIS MORNING SUGGEST THAT THE WINDS
REMAIN AT 45 KNOTS AND THE CENTRAL SURFACE PRESSURE IS STEADY.

THE INTENSITY FORECAST IS MORE COMPLEX THAN USUAL. THE CYCLONE IS
FORECAST TO INTERACT WITH THE HIGH TERRAIN OF HISPANIOLA AND
EASTERN CUBA AND THAT IMPLIES WEAKENING. IN ADDITION...GLOBAL
MODELS WEAKEN OR DISSIPATE THE CYCLONE...AND OBVIOUSLY THESE MODELS
CAN DETECT AN UNFAVORABLE ENVIRONMENT THAT IS NOT APPARENT TO ME.
THIS MAKES IT DIFFICULT TO FORECAST INTENSIFICATION WITH SUCH
INDICATIONS FROM THE RELIABLE GUIDANCE. ON THE OTHER HAND...SHIPS
AND THE GFDL/HWRF MODEL PAIR INTENSIFY THE CYCLONE. GIVEN THIS HIGH
DEGREE OF UNCERTAINTY...THE OFFICIAL FORECAST CALLS FOR NO
SIGNIFICANT CHANGE IN INTENSITY...OR PERHAPS FOR A SLIGHT WEAKENING
AS THE CYCLONE MOVES BY HAITI AND CUBA DURING THE NEXT 24 HOURS.
SOME RE-INTENSIFICATION IS POSSIBLE ONCE EMILY REACHES THE AREA OF
THE BAHAMAS.

SATELLITE AND RECONNAISSANCE PLANE FIXES INDICATE THAT EMILY IS
MOVING TOWARD THE WEST-NORTHWEST OR 285 DEGREES AT 4 KNOTS.  GLOBAL
MODELS CONTINUE TO SHOW A WEAKNESS IN THE SUBTROPICAL RIDGE AND A
TROUGH ALONG THE EAST COAST OF THE UNITED STATES. THIS PATTERN
FAVORS A TURN TO THE NORTHWEST WITHIN THE NEXT 12 TO 24 HOURS WITH
A GRADUAL TURN TO THE NORTH AND NORTHEAST BETWEEN 48 AND 72 HOURS.
IT IS UNCERTAIN HOW FAR WEST EMILY WILL REACH BEFORE RECURVATURE...
PRIMARILY GIVEN THAT GLOBAL MODELS WEAKEN OR DISSIPATE THE CYCLONE.
THE OFFICIAL FORECAST TRACK KEEPS THE CENTER OF EMILY WELL OFF THE
EAST COAST OF FLORIDA...AND GIVEN THE SMALL TROPICAL STORM FORCE
WIND RADII ON THE WESTERN SIDE OF THE CYCLONE...A TROPICAL STORM
WATCH FOR THE FLORIDA SOUTHEAST COAST IS NOT REQUIRED AT THIS TIME.

FORECAST POSITIONS AND MAX WINDS

INIT  04/1500Z 17.3N  72.3W   45 KT  50 MPH
 12H  05/0000Z 18.6N  73.2W   45 KT  50 MPH
 24H  05/1200Z 21.0N  75.5W   35 KT  40 MPH
 36H  06/0000Z 23.0N  77.0W   45 KT  50 MPH
 48H  06/1200Z 25.0N  78.5W   50 KT  60 MPH
 72H  07/1200Z 29.0N  77.5W   60 KT  70 MPH
 96H  08/1200Z 32.5N  72.0W   65 KT  75 MPH
120H  09/1200Z 36.0N  62.0W   55 KT  65 MPH

$$
FORECASTER AVILA



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