000
WTNT41 KNHC 300233
TCDAT1
HURRICANE ALEX DISCUSSION NUMBER  18
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL012010
1000 PM CDT TUE JUN 29 2010
 
ALEX HAS GRADUALLY BECOME BETTER ORGANIZED ON SATELLITE IMAGES AND
DVORAK CLASSIFICATIONS FROM BOTH TAFB AND SAB CONTINUE TO SUPPORT A
CURRENT INTENSITY OF 65 KT.  AN AIR FORCE RESERVE UNIT HURRICANE
HUNTER AIRCRAFT PASSED THROUGH THE CENTER ON A NORTHWEST TO
SOUTHEAST LEG AND MEASURED A CENTRAL PRESSURE OF 973 MB BY
DROPSONDE.  THE SFMR ABOARD THE PLANE MEASURED A SURFACE WIND OF 62
KT JUST TO THE SOUTHEAST OF THE CENTER.  SOON THEREAFTER...THE
AIRCRAFT HAD TO DEPART THE AREA DUE TO RADAR FAILURE.  BASED ON THE
SUBSTANTIAL DROP IN CENTRAL PRESSURE SINCE EARLIER TODAY AND THE
FACT THAT HIGHER SURFACE WINDS ARE LIKELY OCCURRING IN THE
NORTHEAST QUADRANT...ALEX IS BEING UPGRADED TO A 65-KT HURRICANE
FOR THIS ADVISORY.  VERTICAL SHEAR IS FORECAST TO REMAIN BELOW 10
KT FOR THE NEXT 24-48 HOURS SO THE HURRICANE SHOULD REMAIN IN AN
ENVIRONMENT CONDUCIVE FOR INTENSIFICATION UP TO LANDFALL.  THE
SHIPS RAPID INTENSIFICATION INDEX SHOWS A 33 PERCENT PROBABILITY OF
RAPID INTENSIFICATION...I.E. A 30-KT INCREASE OVER 24 HOURS. 
HOWEVER...NONE OF THE OTHER NUMERICAL INTENSITY GUIDANCE SHOWS ALEX
STRENGTHENING BEYOND CATEGORY ONE STATUS PRIOR TO LANDFALL.  THE
OFFICIAL INTENSITY IS VERY CLOSE TO THE LGEM GUIDANCE AND ABOUT THE
SAME AS THAT FROM THE PREVIOUS PACKAGE.
 
ALEX WOBBLED WESTWARD OVER THE PAST SEVERAL HOURS.  AFTER SOME
SMOOTHING...THE INITIAL MOTION ESTIMATE IS 280/8.  SHORT-TERM
FORECASTS FROM DYNAMICAL MODELS SUCH AS THE GFDL AND GFS SUGGEST
THAT THE WESTWARD MOTION IS TEMPORARY AND THAT A WEST-NORTHWESTWARD
TRACK SHOULD RESUME SOON.  THE FLOW TO THE SOUTH OF A MID-
TROPOSPHERIC RIDGE SHOULD STEER THE HURRICANE ON A GENERALLY
WEST-NORTHWESTWARD COURSE ACROSS THE WESTERN GULF OF MEXICO...WITH
ALEX REACHING THE COAST IN ABOUT 24 HOURS.  BECAUSE OF THE JOG TO
THE LEFT...THE NEW NHC FORECAST TRACK HAS BEEN SHIFTED SLIGHTLY TO
THE SOUTH OF THE PREVIOUS ONE.  IT SHOULD BE REPEATED THAT ONE
SHOULD NOT FOCUS ON THE EXACT PREDICTED LANDFALL POINT BECAUSE OF
TRACK FORECAST UNCERTAINTIES...AND ALSO BECAUSE THIS IS A LARGE
TROPICAL CYCLONE. 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      30/0300Z 23.1N  94.8W    65 KT
 12HR VT     30/1200Z 23.7N  96.0W    75 KT
 24HR VT     01/0000Z 24.2N  97.6W    80 KT
 36HR VT     01/1200Z 24.6N  99.2W    55 KT...INLAND
 48HR VT     02/0000Z 24.5N 101.0W    30 KT...INLAND
 72HR VT     03/0000Z...DISSIPATED INLAND
 
$$
FORECASTER PASCH