000
WTNT41 KNHC 290248
TCDAT1
TROPICAL STORM ALEX DISCUSSION NUMBER  14
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL012010
1000 PM CDT MON JUN 28 2010
 
ALTHOUGH THE SATELLITE PRESENTATION OF ALEX CONTINUES TO BE A LITTLE
RAGGED-LOOKING...DATA FROM THE AIR FORCE HURRICANE HUNTERS INDICATE
THAT THE STORM IS GRADUALLY STRENGTHENING.  PEAK 925 MB FLIGHT-LEVEL
WINDS WERE 68 KT AND MAXIMUM SFMR-MEASURED WINDS WERE 53 KT. 
AIRCRAFT OBSERVATIONS ALSO SHOWED THAT THE MINIMUM CENTRAL PRESSURE
HAS DROPPED TO 985 MB...A RATHER LOW VALUE FOR A TROPICAL STORM. 
BASED ON THE WIND MEASUREMENTS...THE INITIAL INTENSITY IS SET TO 55
KT FOR THIS ADVISORY.
 
CENTER FIXES FROM THE RECONNAISSANCE AIRCRAFT INDICATE THAT THE
STORM HAS DRIFTED MOSTLY NORTHWARD OVER THE PAST SEVERAL HOURS...AND
THE INITIAL MOTION ESTIMATE IS 360/4.  THIS MOTION IS BELIEVED TO
BE TEMPORARY BECAUSE THE GLOBAL MODELS ARE FORECASTING A MID-LEVEL
RIDGE TO BUILD TO THE NORTH OF ALEX OVER THE NEXT COUPLE OF
DAYS...WHICH SHOULD INDUCE A GRADUAL BEND OF THE TRACK TO THE LEFT. 
THE TRACK MODEL CONSENSUS HAS SHIFTED ABOUT A HALF DEGREE TO THE
NORTH DUE TO THE RECENT NORTHWARD MOTION...AND THE OFFICIAL
FORECAST IS ADJUSTED SLIGHTLY NORTHWARD AS WELL.  ONE SHOULD NOT
FOCUS ON THE EXACT LANDFALL POINT...HOWEVER...SINCE THE AVERAGE
TRACK FORECAST ERROR IN THE 48- TO 72-HOUR TIME FRAME IS 100-150
NAUTICAL MILES.
 
THE WESTERLY SHEAR THAT WAS AFFECTING ALEX HAS ABATED AND THE SHIPS
MODEL DIAGNOSES A FURTHER DECREASE IN SHEAR...TO BELOW 10 KT IN 24
HOURS.  AS ALEX MOVES AWAY FROM THE SHELF WATERS NEAR THE NORTHWEST
COAST OF THE YUCATAN...IT SHOULD PASS OVER WARMER SEA SURFACE
TEMPERATURES DURING THE NEXT 48 HOURS OR SO...ALTHOUGH THE
PROJECTED TRACK IS NOW A LITTLE TO THE NORTH OF A WARM EDDY OVER
THE SOUTHWEST GULF.  IT IS STILL SOMEWHAT PUZZLING THAT THE GFDL
AND HWRF MODELS STILL DO NOT FORECAST ALEX TO BECOME A
HURRICANE...PARTICULARLY SINCE THE CYCLONE IS APPROACHING HURRICANE
STRENGTH AS WE SPEAK.  THE OFFICIAL INTENSITY FORECAST IS CLOSE TO
THE STATISTICAL LGEM GUIDANCE...AND IS ESSENTIALLY THE SAME AS THE
PREVIOUS NHC FORECAST.
 
GIVEN THE LATEST 36-HR FORECAST POINT AND THE EXTENT OF
TROPICAL-STORM FORCE WINDS IN THE FORECAST...IT IS TIME TO UPGRADE
THE HURRICANE WATCH FOR TO A HURRICANE WARNING FOR THE SOUTH TEXAS
AND NORTHEAST MEXICAN COASTS.
 
  
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      29/0300Z 21.0N  91.6W    55 KT
 12HR VT     29/1200Z 22.2N  92.3W    65 KT
 24HR VT     30/0000Z 23.6N  93.5W    70 KT
 36HR VT     30/1200Z 24.5N  95.2W    75 KT
 48HR VT     01/0000Z 25.2N  96.9W    80 KT
 72HR VT     02/0000Z 25.7N  99.6W    45 KT...INLAND
 96HR VT     03/0000Z 27.0N 102.0W    20 KT...INLAND
120HR VT     04/0000Z...DISSIPATED
 
$$
FORECASTER PASCH/KIMBERLAIN