Issued at 500 AM AST WED SEP 19 2012
000
WTNT44 KNHC 190831
TCDAT4
TROPICAL STORM NADINE DISCUSSION NUMBER 32
NWS NATIONAL HURRICANE CENTER MIAMI FL AL142012
500 AM AST WED SEP 19 2012
NADINE DOES NOT LOOK LIKE A TYPICAL TROPICAL CYCLONE ON SATELLITE.
THE CENTER IS DEVOID OF DEEP CONVECTION...AND MOST OF THE
ASSOCIATED WEATHER IS WITHIN A CURVED BAND WELL TO THE NORTH OF THE
CENTER. DVORAK ESTIMATES STILL SUPPORT AN INITIAL INTENSITY OF 45
KNOTS.
IF THE DIAGNOSIS OF NADINE IS DIFFICULT...THE FORECAST IS EVEN MORE
SO AND HIGHLY UNCERTAIN. THE CYCLONE IS MOVING WITHIN A STRONGLY
SHEARED ENVIRONMENT AND OVER COOL WATERS. THIS NORMALLY WOULD LEAD
TO WEAKENING. HOWEVER...MOST OF THE GLOBAL AND STATISTICAL MODELS
KEEP NADINE AS A STRONG CYCLONE...AND EVEN STRENGTHEN IT A LITTLE
BIT. I AM ASSUMING THAT THIS IS DUE TO THE FORECAST INTERACTION
WITH A DEVELOPING BAROCLINIC ZONE...WHICH IN FACT...THE GFS ASSUMES
WILL BECOME THE DOMINANT SYSTEM. ON THE CONTRARY...THE ECMWF MAKES
NADINE THE PREVAILING ONE. REGARDLESS...IT APPEARS THAT THERE WILL
BE A STRONG TROPICAL STORM...POST-TROPICAL CYCLONE...OR
EXTRATROPICAL LOW DRIFTING EASTWARD TO THE SOUTH OF THE AZORES FOR
A FEW DAYS. AT THIS TIME...THE NHC FORECAST FOLLOWS SOME CONTINUITY
AND ASSUMES THAT THE TROPICAL CYCLONE WILL LOSE ALL ITS ASSOCIATED
CONVECTION OVER THE COOLER WATERS AND BECOME A POST-TROPICAL
CYCLONE IN 48 HOURS OR SO.
THE TRACK GUIDANCE IS NOT IN GOOD AGREEMENT...BUT IS GRADUALLY
TRENDING TOWARD THE GFS SOLUTION WHICH SHOWS A SLOW EASTWARD-MOVING
OR MEANDERING CYCLONE TO THE SOUTH OR EAST OF THE AZORES.
FORECAST POSITIONS AND MAX WINDS
INIT 19/0900Z 36.4N 32.1W 45 KT 50 MPH
12H 19/1800Z 37.0N 32.0W 45 KT 50 MPH
24H 20/0600Z 36.6N 31.1W 45 KT 50 MPH
36H 20/1800Z 35.5N 29.8W 45 KT 50 MPH
48H 21/0600Z 34.5N 28.0W 45 KT 50 MPH...POST-TROPICAL
72H 22/0600Z 34.0N 25.0W 45 KT 50 MPH...POST-TROPICAL
96H 23/0600Z 34.0N 24.0W 45 KT 50 MPH...POST-TROPICAL
120H 24/0600Z 34.0N 22.0W 40 KT 45 MPH...POST-TROPICAL
$$
FORECASTER AVILA
Continue reading...
000
WTNT44 KNHC 190831
TCDAT4
TROPICAL STORM NADINE DISCUSSION NUMBER 32
NWS NATIONAL HURRICANE CENTER MIAMI FL AL142012
500 AM AST WED SEP 19 2012
NADINE DOES NOT LOOK LIKE A TYPICAL TROPICAL CYCLONE ON SATELLITE.
THE CENTER IS DEVOID OF DEEP CONVECTION...AND MOST OF THE
ASSOCIATED WEATHER IS WITHIN A CURVED BAND WELL TO THE NORTH OF THE
CENTER. DVORAK ESTIMATES STILL SUPPORT AN INITIAL INTENSITY OF 45
KNOTS.
IF THE DIAGNOSIS OF NADINE IS DIFFICULT...THE FORECAST IS EVEN MORE
SO AND HIGHLY UNCERTAIN. THE CYCLONE IS MOVING WITHIN A STRONGLY
SHEARED ENVIRONMENT AND OVER COOL WATERS. THIS NORMALLY WOULD LEAD
TO WEAKENING. HOWEVER...MOST OF THE GLOBAL AND STATISTICAL MODELS
KEEP NADINE AS A STRONG CYCLONE...AND EVEN STRENGTHEN IT A LITTLE
BIT. I AM ASSUMING THAT THIS IS DUE TO THE FORECAST INTERACTION
WITH A DEVELOPING BAROCLINIC ZONE...WHICH IN FACT...THE GFS ASSUMES
WILL BECOME THE DOMINANT SYSTEM. ON THE CONTRARY...THE ECMWF MAKES
NADINE THE PREVAILING ONE. REGARDLESS...IT APPEARS THAT THERE WILL
BE A STRONG TROPICAL STORM...POST-TROPICAL CYCLONE...OR
EXTRATROPICAL LOW DRIFTING EASTWARD TO THE SOUTH OF THE AZORES FOR
A FEW DAYS. AT THIS TIME...THE NHC FORECAST FOLLOWS SOME CONTINUITY
AND ASSUMES THAT THE TROPICAL CYCLONE WILL LOSE ALL ITS ASSOCIATED
CONVECTION OVER THE COOLER WATERS AND BECOME A POST-TROPICAL
CYCLONE IN 48 HOURS OR SO.
THE TRACK GUIDANCE IS NOT IN GOOD AGREEMENT...BUT IS GRADUALLY
TRENDING TOWARD THE GFS SOLUTION WHICH SHOWS A SLOW EASTWARD-MOVING
OR MEANDERING CYCLONE TO THE SOUTH OR EAST OF THE AZORES.
FORECAST POSITIONS AND MAX WINDS
INIT 19/0900Z 36.4N 32.1W 45 KT 50 MPH
12H 19/1800Z 37.0N 32.0W 45 KT 50 MPH
24H 20/0600Z 36.6N 31.1W 45 KT 50 MPH
36H 20/1800Z 35.5N 29.8W 45 KT 50 MPH
48H 21/0600Z 34.5N 28.0W 45 KT 50 MPH...POST-TROPICAL
72H 22/0600Z 34.0N 25.0W 45 KT 50 MPH...POST-TROPICAL
96H 23/0600Z 34.0N 24.0W 45 KT 50 MPH...POST-TROPICAL
120H 24/0600Z 34.0N 22.0W 40 KT 45 MPH...POST-TROPICAL
$$
FORECASTER AVILA
Continue reading...