Issued at 800 AM CDT THU OCT 03 2013
000
WTNT42 KNHC 031312
TCDAT2
TROPICAL STORM KAREN SPECIAL DISCUSSION NUMBER 1
NWS NATIONAL HURRICANE CENTER MIAMI FL AL122013
800 AM CDT THU OCT 03 2013
AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT INVESTIGATING THE
AREA OF LOW PRESSURE JUST NORTH OF THE YUCATAN PENINSULA FOUND A
CLOSED CIRCULATION WITH A CENTRAL PRESSURE OF 1004 MB AND SURFACE
WINDS AROUND 50 KT. BASED ON THESE DATA...ADVISORIES ARE BEING
INITIATED ON TROPICAL STORM KAREN. MOST OF THE DEEP CONVECTION IS
DISPLACED NORTH AND EAST OF THE CENTER DUE TO MODERATE
SOUTHWESTERLY SHEAR. THE SHEAR IS EXPECTED TO CONTINUE AND THE
INTENSIFY IN 2 TO 3 DAYS. THIS ENVIRONMENT SHOULD ONLY SUPPORT
GRADUAL INTENSIFICATION DURING THE NEXT DAY OR SO...WITH SOME
WEAKENING EXPECTED AS KAREN APPROACHES THE GULF COAST...BUT THE
STORM COULD STILL BE NEAR HURRICANE STRENGTH AT LANDFALL.
THE INITIAL MOTION ESTIMATE IS AN UNCERTAIN 340/11 GIVEN THE RECENT
FORMATION OF THE CENTER. KAREN IS EXPECTED TO GRADUALLY TURN
NORTHWARD AROUND THE PERIPHERY OF A MID-LEVEL RIDGE AND THEN
ACCELERATE NORTHEASTWARD LATE IN THE PERIOD AHEAD OF A
MID/UPPER-LEVEL TROUGH. ALL OF THE TRACK GUIDANCE IS IN AGREEMENT
ON THIS GENERAL SCENARIO...HOWEVER THERE IS SIGNIFICANT WEST/EAST
SPREAD IN THE TRACKS...WITH THE ECMWF ON THE WEST SIDE OF THE
GUIDANCE ENVELOPE AND THE GFS FARTHEST EAST. THE NHC TRACK FORECAST
IS NEAR THE MIDDLE OF THE GUIDANCE ENVELOPE AND THE TVCA
MULTI-MODEL CONSENSUS THROUGH LANDFALL. NOTE THAT A TRACK FARTHER
EAST WOULD LIKELY RESULT IN A STRONGER STORM...WHILE KAREN WOULD
LIKELY BE WEAKER IF IT TAKES A TRACK FARTHER WEST.
GIVEN THE FORECAST...HURRICANE AND TROPICAL STORM WATCHES HAVE BEEN
ISSUED FOR PORTIONS OF THE NORTHERN GULF COAST.
FORECAST POSITIONS AND MAX WINDS
INIT 03/1300Z 22.0N 87.6W 50 KT 60 MPH
12H 03/1800Z 23.4N 88.2W 55 KT 65 MPH
24H 04/0600Z 25.4N 88.8W 60 KT 70 MPH
36H 04/1800Z 27.0N 88.9W 65 KT 75 MPH
48H 05/0600Z 28.3N 88.7W 60 KT 70 MPH
72H 06/0600Z 31.0N 87.5W 50 KT 60 MPH...INLAND
96H 07/0600Z 34.5N 83.0W 25 KT 30 MPH...POST-TROP/EXTRATROP
120H 08/0600Z 38.5N 77.5W 20 KT 25 MPH...POST-TROP/EXTRATROP
$$
FORECASTER BRENNAN
Continue reading...
000
WTNT42 KNHC 031312
TCDAT2
TROPICAL STORM KAREN SPECIAL DISCUSSION NUMBER 1
NWS NATIONAL HURRICANE CENTER MIAMI FL AL122013
800 AM CDT THU OCT 03 2013
AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT INVESTIGATING THE
AREA OF LOW PRESSURE JUST NORTH OF THE YUCATAN PENINSULA FOUND A
CLOSED CIRCULATION WITH A CENTRAL PRESSURE OF 1004 MB AND SURFACE
WINDS AROUND 50 KT. BASED ON THESE DATA...ADVISORIES ARE BEING
INITIATED ON TROPICAL STORM KAREN. MOST OF THE DEEP CONVECTION IS
DISPLACED NORTH AND EAST OF THE CENTER DUE TO MODERATE
SOUTHWESTERLY SHEAR. THE SHEAR IS EXPECTED TO CONTINUE AND THE
INTENSIFY IN 2 TO 3 DAYS. THIS ENVIRONMENT SHOULD ONLY SUPPORT
GRADUAL INTENSIFICATION DURING THE NEXT DAY OR SO...WITH SOME
WEAKENING EXPECTED AS KAREN APPROACHES THE GULF COAST...BUT THE
STORM COULD STILL BE NEAR HURRICANE STRENGTH AT LANDFALL.
THE INITIAL MOTION ESTIMATE IS AN UNCERTAIN 340/11 GIVEN THE RECENT
FORMATION OF THE CENTER. KAREN IS EXPECTED TO GRADUALLY TURN
NORTHWARD AROUND THE PERIPHERY OF A MID-LEVEL RIDGE AND THEN
ACCELERATE NORTHEASTWARD LATE IN THE PERIOD AHEAD OF A
MID/UPPER-LEVEL TROUGH. ALL OF THE TRACK GUIDANCE IS IN AGREEMENT
ON THIS GENERAL SCENARIO...HOWEVER THERE IS SIGNIFICANT WEST/EAST
SPREAD IN THE TRACKS...WITH THE ECMWF ON THE WEST SIDE OF THE
GUIDANCE ENVELOPE AND THE GFS FARTHEST EAST. THE NHC TRACK FORECAST
IS NEAR THE MIDDLE OF THE GUIDANCE ENVELOPE AND THE TVCA
MULTI-MODEL CONSENSUS THROUGH LANDFALL. NOTE THAT A TRACK FARTHER
EAST WOULD LIKELY RESULT IN A STRONGER STORM...WHILE KAREN WOULD
LIKELY BE WEAKER IF IT TAKES A TRACK FARTHER WEST.
GIVEN THE FORECAST...HURRICANE AND TROPICAL STORM WATCHES HAVE BEEN
ISSUED FOR PORTIONS OF THE NORTHERN GULF COAST.
FORECAST POSITIONS AND MAX WINDS
INIT 03/1300Z 22.0N 87.6W 50 KT 60 MPH
12H 03/1800Z 23.4N 88.2W 55 KT 65 MPH
24H 04/0600Z 25.4N 88.8W 60 KT 70 MPH
36H 04/1800Z 27.0N 88.9W 65 KT 75 MPH
48H 05/0600Z 28.3N 88.7W 60 KT 70 MPH
72H 06/0600Z 31.0N 87.5W 50 KT 60 MPH...INLAND
96H 07/0600Z 34.5N 83.0W 25 KT 30 MPH...POST-TROP/EXTRATROP
120H 08/0600Z 38.5N 77.5W 20 KT 25 MPH...POST-TROP/EXTRATROP
$$
FORECASTER BRENNAN
Continue reading...