149 
 WTNT44 KNHC 080833
 TCDAT4
  
 TROPICAL STORM MARIA DISCUSSION NUMBER   7
 NWS NATIONAL HURRICANE CENTER MIAMI FL       AL142011
 500 AM AST THU SEP 08 2011
 
 MARIA CURRENTLY HAS A RATHER DISORGANIZED APPEARANCE ON SATELLITE
 IMAGES...AND CONSISTS PRIMARILY OF A RATHER SHAPELESS CLUSTER OF
 DEEP CONVECTION WITH A FEW THUNDERSTORMS TO THE WEST-SOUTHWEST OF
 THE CLUSTER.  THERE IS LITTLE...IF ANY...EVIDENCE OF BANDING
 FEATURES.  AN ASCAT PASS FROM SEVERAL HOURS AGO INDICATED THAT THE
 MAXIMUM WINDS REMAIN NEAR 45 KT.  HOWEVER...DATA FROM THIS PASS ALSO
 CAST SOME DOUBT AS TO WHETHER THE SYSTEM HAS A CLOSED CIRCULATION
 AT THIS TIME.  VISIBLE IMAGERY AND AN AIRCRAFT MISSION LATER TODAY
 SHOULD GIVE MORE INFORMATION ON THE STATUS OF MARIA.  
 
 NO CHANGE IS MADE TO THE INTENSITY FORECAST.  AN UPPER-LEVEL LOW OR
 TROUGH TO THE NORTHWEST OF THE STORM HAS BEEN IMPARTING ABOUT 20 KT
 OF SOUTH-SOUTHWESTERLY SHEAR OVER THE TROPICAL CYCLONE...AND
 INHIBITING STRENGTHENING.  GLOBAL MODELS INDICATE THAT THIS
 LOW/TROUGH WILL MOVE MORE OR LESS IN TANDEM WITH MARIA THROUGH
 ABOUT 72 HOURS...AND CONTINUE TO PRODUCE SIGNIFICANT SHEAR ON THE
 SYSTEM.  THE OFFICIAL FORECAST SHOWS NO STRENGTHENING THROUGH 72
 HOURS FOLLOWED BY SOME INCREASE IN INTENSITY AS THE IMPACT OF THE
 AFOREMENTIONED UPPER-LEVEL LOW IS EXPECTED TO LESSEN.  THE NHC WIND
 SPEED FORECAST IS ROUGHLY BETWEEN THE LATEST LGEM GUIDANCE AND THE
 INTENSITY MODEL CONSENSUS.
 
 THE CENTER IS QUITE DIFFICULT TO FIND...BUT IT IS PRESUMED THAT
 MARIA HAS BEEN MAINTAINING A MOTION OF 275/20. A CONTINUED WESTWARD
 MOTION IS LIKELY FOR ANOTHER DAY OR SO AS THE STORM MOVES ON THE
 SOUTHERN SIDE OF A SUBTROPICAL RIDGE. SOME DECELERATION IS
 PREDICTED AS THE RIDGE WEAKENS A LITTLE WITH TIME. IN 48 TO 72
 HOURS...MARIA SHOULD BE NEARING A WEAKNESS IN THE RIDGE AND TURN
 WEST-NORTHWESTWARD. AS USUAL...THERE IS A FAIR AMOUNT OF
 UNCERTAINTY IN THE TRACK 4 TO 5 DAYS FROM NOW. A BROAD 500 MB
 TROUGH...MOVING OFF THE U.S EAST COAST...IS SHOWN BY THE GLOBAL
 MODELS TO WEAKEN THE RIDGE ENOUGH TO CAUSE MARIA TO TURN
 NORTHWESTWARD BY 96 HOURS. IF THE TROUGH TURNS OUT TO BE WEAKER
 THAN CURRENTLY PREDICTED...IT COULD DELAY THE NORTHWESTWARD TURN.
 THE OFFICIAL FORECAST IS VERY CLOSE TO THE PREVIOUS ONE AND ROUGHLY 
 IN THE MIDDLE OF THE TRACK GUIDANCE ENVELOPE...BRACKETED BY THE
 U.K. MET OFFICE MODEL ON THE LEFT AND BY THE GFS AND HWRF MODELS ON
 THE RIGHT.
  
 FORECAST POSITIONS AND MAX WINDS
  
 INIT  08/0900Z 13.5N  48.2W   45 KT  50 MPH
  12H  08/1800Z 13.8N  51.2W   45 KT  50 MPH
  24H  09/0600Z 14.5N  54.7W   45 KT  50 MPH
  36H  09/1800Z 15.3N  57.8W   45 KT  50 MPH
  48H  10/0600Z 16.7N  60.8W   45 KT  50 MPH
  72H  11/0600Z 19.5N  65.5W   45 KT  50 MPH
  96H  12/0600Z 23.0N  69.0W   50 KT  60 MPH
 120H  13/0600Z 26.0N  72.0W   60 KT  70 MPH
  
 $$
 FORECASTER PASCH