[Tropical] Tropical Cyclone Discussion

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WTNT45 KNHC 090848
TCDAT5

TROPICAL STORM ERNESTO DISCUSSION NUMBER  32
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL052012
400 AM CDT THU AUG 09 2012

SATELLITE IMAGERY AND RADAR DATA FROM MEXICO HAS SHOWN A SIGNIFICANT
INCREASE IN DEEP CONVECTION AND IMPROVED ORGANIZATION OF THE
THUNDERSTORM ACTIVITY ASSOCIATED WITH ERNESTO OVERNIGHT.  AN AIR
FORCE RESERVE HURRICANE HUNTER MISSION...AROUND 0600 UTC...MEASURED
A PEAK 850 MB FLIGHT-LEVEL WIND OF 86 KT.  NORMALLY THIS WOULD
EQUATE TO HURRICANE INTENSITY.  HOWEVER...IT APPEARS..BASED ON
MAXIMUM SFMR WINDS OF 55-59 KT AND A STANDARD REDUCED MEAN BOUNDARY
LAYER WIND OF 58 KT FROM A DROPWINDSONDE...THAT THESE WINDS WERE
NOT BEING EFFICIENTLY MIXED TO THE SURFACE. THEREFORE...THE INITIAL
INTENSITY IS SET AT 60 KT.  ERNESTO APPEARS TO HAVE ABOUT 6 HOURS
OR SO OVER THE EXTREME SOUTHERN BAY OF CAMPECHE IN WHICH TO
INTENSIFY...AND THE OFFICIAL FORECAST CALLS FOR THE CYCLONE TO
REGAIN HURRICANE STRENGTH BEFORE LANDFALL.  AFTER LANDFALL...
ERNESTO SHOULD RAPIDLY WEAKEN AND DISSIPATE OVER THE HIGH TERRAIN
OF MEXICO.

THE AIRCRAFT FIXES AND RADAR IMAGERY INDICATE THAT ERNESTO HAS
ACCELERATED WESTWARD DURING THE PAST SEVERAL HOURS.  THE INITIAL
MOTION ESTIMATE IS 270 AT 14 KT.  THE TRACK GUIDANCE IS IN GOOD
AGREEMENT IN SHOWING SOME DECELERATION IN FORWARD SPEED AND A
BEND TO THE WEST-SOUTHWEST AS ERNESTO NEARS THE COAST.  THE OFFICIAL
FORECAST IS NEAR THE MIDDLE OF THE TIGHTLY CLUSTERED MODEL ENVELOPE
AND IS VERY SIMILAR TO THE PREVIOUS TRACK.

HEAVY RAINFALL AND THE THREAT OF FLASH FLOODING IS LIKELY OVER MUCH
OF SOUTHERN MEXICO FOR THE NEXT FEW DAYS.

FORECAST POSITIONS AND MAX WINDS

INIT  09/0900Z 18.7N  93.6W   60 KT  70 MPH
 12H  09/1800Z 18.5N  95.2W   65 KT  75 MPH...INLAND
 24H  10/0600Z 18.0N  96.8W   40 KT  45 MPH...INLAND
 36H  10/1800Z 17.7N  98.0W   25 KT  30 MPH...INLAND
 48H  11/0600Z...DISSIPATED

$$
FORECASTER BROWN
 
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