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Tropical Storm HARVEY (Text)

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TROPICAL STORM HARVEY DISCUSSION NUMBER   6
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL082011
400 AM CDT SAT AUG 20 2011
 
AFTER A LULL BETWEEN 0400 AND 0600 UTC...DEEP CONVECTION HAS
RE-BLOSSOMED NEAR THE ESTIMATED CENTER OF HARVEY...WHICH IS VERY
NEAR ROATAN ACCORDING TO A FEW SURFACE OBSERVATIONS ON THAT ISLAND.
SINCE THE CONVECTIVE STRUCTURE LOOKS SIMILAR TO THE STRUCTURE WHEN
THE LAST HURRICANE HUNTER MISSION WAS INVESTIGATING THIS SYSTEM...
THE INITIAL INTENSITY WILL BE MAINTAINED AT 50 KT.  ANOTHER RECON
MISSION IS SCHEDULED TO REACH HARVEY AROUND 1200 UTC.
 
BASED ON THE ROATAN OBSERVATIONS...HARVEY MAY HAVE PICKED UP SOME
SPEED...AND ITS INITIAL MOTION IS ESTIMATED AT 275/10.  THE
SUBTROPICAL RIDGE TO THE NORTH OF THE CYCLONE IS EXPECTED TO
CONTINUE STEERING HARVEY ON A NEARLY CONSTANT WESTWARD HEADING UNTIL
DISSIPATION IN 72 HOURS.  THE NEW OFFICIAL FORECAST IS JUST A LITTLE
SOUTH OF THE PREVIOUS ONE AND GENERALLY LIES NEAR THE GFS...
ECMWF...AND THE MULTI-MODEL CONSENSUS TVCA.
 
ENVIRONMENTAL CONDITIONS ARE STILL EXPECTED TO BE CONDUCIVE FOR SOME
STRENGTHENING BEFORE HARVEY REACHES THE COAST OF BELIZE LATER
TODAY.  THE STATISTICAL SHIPS AND LGEM MODELS ARE THE HIGHEST OF
THE INTENSITY GUIDANCE AND INDICATE THAT HARVEY COULD BE JUST BELOW
HURRICANE STRENGTH AT 12 HOURS.  SINCE LANDFALL ON THE OFFICIAL
FORECAST TRACK WOULD BE WITHIN THE 12 TO 18 HOUR PERIOD...IT IS
STILL POSSIBLE THAT HARVEY COULD BECOME A HURRICANE JUST BEFORE
MOVING INLAND ACROSS THE COAST OF BELIZE EVEN THOUGH NOT EXPLICITLY
SHOWN IN THE OFFICIAL FORECAST.  IN FACT...THERE IS A 1 IN 3 CHANCE
OF THAT OCCURRING...BASED ON THE CURRENT FORECAST AND RECENT NHC
INTENSITY ERRORS.  WEAKENING IS EXPECTED AFTER HARVEY MOVES
INLAND...AND THE NHC INTENSITY FORECAST FROM 24 HOURS AND BEYOND
FOLLOWS THE DECAY OF THE STATISTICAL MODELS.  DISSIPATION IS NOW
EXPECTED BY 72 HOURS.
 
BASED ON THE UPDATED FORECAST TRACK...THE GOVERNMENT OF GUATEMALA
HAS UPGRADED THE TROPICAL STORM WATCH TO A TROPICAL STORM WARNING
ALONG THE GUATEMALAN COAST.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  20/0900Z 16.4N  86.5W   50 KT  60 MPH
 12H  20/1800Z 16.5N  87.7W   60 KT  70 MPH
 24H  21/0600Z 16.7N  89.6W   50 KT  60 MPH...INLAND
 36H  21/1800Z 16.9N  92.0W   35 KT  40 MPH...INLAND
 48H  22/0600Z 17.2N  94.6W   25 KT  30 MPH...INLAND
 72H  23/0600Z...DISSIPATED
 
$$
FORECASTER BERG/STEWART
 
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