[Tropical] Tropical Cyclone Discussion

[EMWIN Server]

WTNT45 KNHC 042031
TCDAT5

TROPICAL STORM ERNESTO DISCUSSION NUMBER  13
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL052012
500 PM EDT SAT AUG 04 2012

A RECONNAISSANCE PLANE EARLIER THIS MORNING FOUND A WEAKER
CYCLONE...BUT DURING THE LAST PASS THROUGH THE CENTER AROUND
NOON...THE PLANE REPORTED THAT THE CENTRAL PRESSURE HAD DROPPED TO
1004 MB FROM 1008 MB...AND FOUND A BETTER DEFINED CIRCULATION
CENTER. SINCE THAT TIME...THE SATELLITE PRESENTATION HAS CONTINUED
TO INCREASE IN ORGANIZATION. THE CENTER IS EMBEDDED WITHIN A
CIRCULAR AREA OF DEEP CONVECTION...AND THE OUTFLOW IS WELL
ESTABLISHED WHICH IS NOT COMMON FOR A CYCLONE IN THE CENTRAL
CARIBBEAN. T-NUMBERS WERE 3.5 AND 3.0 AT 1800 UTC...AND OBJECTIVE
NUMBERS HAVE REACHED 4.3 ON THE DVORAK SCALE DURING THE PAST HOUR.
ON THIS BASIS...THE INTENSITY HAS BEEN CONSERVATIVELY BEEN ADJUSTED
UPWARD TO 50 KNOTS. HOWEVER... GIVEN THE SATELLITE PRESENTATION...
THE NEXT RECONNAISSANCE PLANE COULD FIND STRONGER WINDS.

AS INDICATED IN THE PREVIOUS ADVISORY...I DO NOT HAVE ANY REASONS TO
FORECAST WEAKENING AS SOME OF THE DYNAMICAL MODELS PREDICT...
INCLUDING THE HWRF AND THE GFDL. THE SHEAR IS LOW AHEAD OF THE
CYCLONE 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 AS SUGGESTED
BY THE SHIPS AND LGEM MODELS.

ERNESTO CONTINUES TO MOVE TOWARD THE WEST OR 280 DEGREES AT 16
KNOTS...EMBEDDED IN THE FLOW SOUTH OF THE SUBTROPICAL RIDGE. THIS
GENERAL TRACK IS EXPECTED TO CONTINUE FOR THE NEXT 24 TO 48 HOURS.
AFTER THAT...THE SUBTROPICAL HIGH IS FORECAST TO WEAKEN...RESULTING
IN ERNESTO TURNING MORE TOWARD THE WEST-NORTHWEST WITH A DECREASE
IN FORWARD SPEED. THE OFFICIAL FORECAST IS VERY CLOSE TO THE
SOLUTION OF MOST THE GLOBAL MODELS...BRINGING ERNESTO OVER THE
NORTHWESTERN CARIBBEAN AND ACROSS THE YUCATAN PENINSULA. AT THIS
TIME...THE NHC FORECAST DISREGARDS THE NORTHWARD TURN INDICATED BY
THE GFDL/HWRF MODEL PAIR.


FORECAST POSITIONS AND MAX WINDS

INIT  04/2100Z 14.8N  70.1W   50 KT  60 MPH
 12H  05/0600Z 15.2N  72.6W   50 KT  60 MPH
 24H  05/1800Z 15.7N  76.0W   55 KT  65 MPH
 36H  06/0600Z 16.0N  79.0W   65 KT  75 MPH
 48H  06/1800Z 16.5N  81.5W   70 KT  80 MPH
 72H  07/1800Z 18.0N  84.5W   75 KT  85 MPH
 96H  08/1800Z 19.5N  87.0W   80 KT  90 MPH
120H  09/1800Z 21.5N  90.5W   60 KT  70 MPH

$$
FORECASTER AVILA



This weather bulletin was brought to you by:
www.nashvilleweather.net