[Tropical] Tropical Cyclone Discussion

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WTNT45 KNHC 041445
TCDAT5

TROPICAL STORM ERNESTO DISCUSSION NUMBER  12
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL052012
1100 AM AST SAT AUG 04 2012

DESPITE THE EXCELLENT PRESENTATION ON SATELLITE WITH CYCLONICALLY
CURVED CONVECTIVE BANDS AND A WELL ESTABLISHED UPPER-LEVEL
OUTFLOW...DATA FROM A RECONNAISSANCE PLANE INDICATE THAT
ERNESTO HAS NOT BECOME ANY BETTER ORGANIZED. IN FACT...THE WINDS
HAVE DECREASED TO 45 KT AND THE PRESSURE HAS RISEN TO 1008 MB.  I
DO NOT HAVE ANY REASONS FOR THE CURRENT WEAKENING BUT I HAVE NO
REASON TO FORECAST ADDITIONAL WEAKENING EITHER. THE SHEAR IS
ANTICIPATED TO REMAIN LOW ACROSS THE CARIBBEAN...AND ERNESTO WILL
MOVE OVER AN OCEAN WITH HIGHER HEAT CONTENT. GIVEN SUCH
CONDITIONS...THE OFFICIAL FORECAST CALLS FOR ERNESTO TO BECOME A
HURRICANE IN THE WESTERN CARIBBEAN. THIS FORECAST IS UNCERTAIN
SINCE MODELS ARE IN DISAGREEMENT. SHIPS...LGEM AND THE GFDL
FORECAST ERNESTO TO BECOME A HURRICANE WHILE THE HWRF EITHER
FORECASTS NO CHANGE OR WEAKENING.

ERNESTO IS MOVING TOWARD THE WEST-NORTHWEST OR 285 DEGREES AT 16
KNOTS EMBEDDEED IN THE FLOW SOUTH OF THE SUBTROPICAL RIDGE. THIS
TRACK IS EXPECTED TO CONTINUE FOR THE NEXT 24 TO 48 HOURS. AFTER
THAT...THERE WILL PROBABLY BE A WEAKENING OF THE RIDGE AND ERNESTO
COULD TURN A LITTLE MORE TO THE NORTHWEST TOWARD THE YUCATAN
PENINSULA AND THE BAY OF CAMPECHE. MODELS ARE IN GOOD AGREEMENT
WITH THIS SCENARIO DURING THE NEXT TWO DAYS...BUT BEYOND THAT
TIME...THERE ARE LARGE DIFFERENCES.  BOTH THE GFDL AND HWRF TURN
ERNESTO NORTHWARD...AND THE RELIABLE GLOBAL MODELS KEEP THE CYCLONE
ON A WEST-NORTHWEST TRACK. THE OFFICIAL FORECAST IS HEAVILY BIASED
TOWARD THE GLOBAL MODELS AND IS VERY SIMILAR TO THE PREVIOUS NHC
FORECAST.



FORECAST POSITIONS AND MAX WINDS

INIT  04/1500Z 14.4N  68.7W   45 KT  50 MPH
 12H  05/0000Z 14.8N  71.2W   45 KT  50 MPH
 24H  05/1200Z 15.5N  74.5W   50 KT  60 MPH
 36H  06/0000Z 15.7N  77.5W   65 KT  75 MPH
 48H  06/1200Z 16.5N  80.5W   70 KT  80 MPH
 72H  07/1200Z 18.0N  84.0W   80 KT  90 MPH
 96H  08/1200Z 19.5N  87.0W   70 KT  80 MPH
120H  09/1200Z 22.0N  90.5W   60 KT  70 MPH

$$
FORECASTER AVILA



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