[Tropical] Tropical Cyclone Discussion

[EMWIN Server]

WTNT42 KNHC 100840
TCDAT2

TROPICAL DEPRESSION SEVEN DISCUSSION NUMBER   3
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL072012
500 AM AST FRI AUG 10 2012

THE OVERALL ORGANIZATION OF THE DEPRESSION HAS NOT CHANGED
OVERNIGHT.  A COUPLE OF MICROWAVE OVERPASSES HAVE REVEALED A
SMALL...BUT WELL-DEFINED CIRCULATION WITH A SMALL BAND OF
CONVECTION TO THE NORTHEAST OF THE CENTER.  NOAA BUOY 41041
REPORTED PEAK 1-MINUTE SUSTAINED WINDS OF 29 KT AND A MINIMUM
PRESSURE OF 1010.9 MB AS THE CENTER PASSED ABOUT 30 TO 40 N MI
SOUTH OF THE BUOY AROUND 0600 UTC.  BASED ON THE BUOY
OBSERVATIONS AND LACK OF STRUCTURAL CHANGE...THE INITIAL
WIND SPEED WILL REMAIN 30 KT.

THE CYCLONE IS FORECAST TO MOVE OVER INCREASING SSTS AND REMAIN IN
A LOW SHEAR ENVIRONMENT DURING THE NEXT DAY OR SO.  HOWEVER...DRY
AIR NEAR THE CIRCULATION WILL LIKELY ALLOW FOR ONLY MODEST
INTENSIFICATION.  THE GLOBAL MODELS INDICATE THAT THE DEPRESSION
WILL ENCOUNTER INCREASING SOUTHERLY TO SOUTHWESTERLY UPPER-LEVEL
WINDS AS IT NEARS THE WINDWARD ISLANDS.  THIS INCREASING SHEAR WILL
LIKELY HALT ANY INTENSIFICATION.  THE OFFICIAL INTENSITY FORECAST
IS SIMILAR TO THE PREVIOUS ADVISORY AND IS CLOSEST TO THE SHIPS
GUIDANCE.  IT SHOULD BE NOTED THAT BOTH THE GFS AND ECMWF WEAKEN
THE SYSTEM AND SHOW IT BECOMING AN OPEN WAVE IN THE EASTERN
CARIBBEAN.  FOR NOW...THE NHC FORECAST DOES NOT INDICATE
WEAKENING...BUT THAT IS ONE POSSIBILITY GIVEN THAT THE SYSTEM IS
SMALL...MAKING IT MORE PRONE TO THE EXPECTED INCREASE IN SHEAR
IN A COUPLE OF DAYS.

THE DEPRESSION CONTINUES MOVING QUICKLY WESTWARD OR 270 DEGREES AT
17 KT.  THE CYCLONE IS EXPECTED TO REMAIN ON THIS GENERAL HEADING
AND SPEED DURING THE NEXT FEW DAYS AS IT IS STEERED WESTWARD BY A
MID-LEVEL RIDGE OVER THE CENTRAL ATLANTIC.  BEYOND THREE DAYS THE
RIDGE IS EXPECTED TO WEAKEN WHICH WOULD CAUSE THE CYCLONE TO TURN
WEST-NORTHWESTWARD.  THE NHC FORECAST REMAINS ALONG THE SOUTHERN
SIDE OF THE GUIDANCE ENVELOPE AND IS IN BEST AGREEMENT WITH THE
GFS MODEL.




FORECAST POSITIONS AND MAX WINDS

INIT  10/0900Z 13.6N  47.2W   30 KT  35 MPH
 12H  10/1800Z 13.6N  49.9W   35 KT  40 MPH
 24H  11/0600Z 13.7N  53.3W   40 KT  45 MPH
 36H  11/1800Z 13.9N  56.8W   45 KT  50 MPH
 48H  12/0600Z 14.3N  60.0W   45 KT  50 MPH
 72H  13/0600Z 15.3N  66.6W   45 KT  50 MPH
 96H  14/0600Z 16.5N  73.0W   45 KT  50 MPH
120H  15/0600Z 17.5N  79.5W   45 KT  50 MPH

$$
FORECASTER BROWN


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