000
WTNT43 KNHC 240832
TCDAT3
 
TROPICAL STORM RINA DISCUSSION NUMBER   3
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL182011
500 AM EDT MON OCT 24 2011
 
THE CLOUD PATTERN OF RINA HAS NOT BECOME BETTER ORGANIZED OVER THE
PAST SEVERAL HOURS. THERE IS ONE LARGE CLUSTER OF DEEP CONVECTION
JUST TO THE NORTH OF THE ESTIMATED CENTER POSITION WITH A COUPLE OF
ADJACENT SMALLER CLUSTERS...BUT NOT MUCH EVIDENCE OF CURVED BANDS.
VERY LITTLE THUNDERSTORM ACTIVITY IS CURRENTLY OCCURRING OVER THE
SOUTHERN HALF OF THE CIRCULATION. THE INITIAL WIND SPEED IS HELD AT
35 KT IN AGREEMENT WITH THE LATEST OBJECTIVE DVORAK INTENSITY
ESTIMATES FROM UW/CIMSS. RINA IS IN AN ENVIRONMENT OF MODERATE
SOUTH-SOUTHEASTERLY VERTICAL BUT IS EXHIBITING FAIRLY WELL-DEFINED
UPPER-LEVEL OUTFLOW OVER ALL BUT THE SOUTHEASTERN QUADRANT OF THE
CIRCULATION. THE SHIPS GUIDANCE INDICATES THAT A SLIGHT LESSENING
OF THE SHEAR COULD OCCUR IN THE NEXT COUPLE OF DAYS. TOTAL
PRECIPITABLE WATER IMAGERY ALONG WITH SURFACE AND RADIOSONDE DATA
SHOW A SIGNIFICANTLY DRIER LOW- TO MID-TROPOSPHERIC AIR MASS EXISTS
JUST TO THE NORTH AND WEST OF THE STORM. GIVEN THESE MARGINALLY
CONDUCIVE ENVIRONMENTAL FACTORS...ONLY SLOW STRENGTHENING IS
FORECAST. THE OFFICIAL INTENSITY FORECAST IS VERY SIMILAR TO THE
LGEM GUIDANCE AND BELOW THE GFDL AND HWRF MODELS.
 
USING A COMBINATION OF CENTER FIXES FROM GEOSTATIONARY AND MICROWAVE
IMAGERY YIELDS AN INITIAL MOTION ESTIMATE OF 330/5.  A 500 MB SHORT
WAVE TROUGH IS CURRENTLY PASSING TO THE NORTH AND WILL SOON BYPASS
THE TROPICAL CYCLONE.  AFTER THE TROUGH DEPARTS THE AREA...A WEAK
RIDGE IS FORECAST TO DEVELOP TO THE NORTH OF RINA.  THIS STEERING
PATTERN SHOULD CAUSE THE CYCLONE TO TURN TOWARD THE WEST...BUT AT A
VERY SLOW RATE OF FORWARD SPEED...DURING THE NEXT 48 HOURS.  BY THE
END OF THE FORECAST PERIOD A STRONGER TROUGH MOVES INTO THE EASTERN
UNITED STATES...WHICH SHOULD INDUCE A NORTHWARD TURN.  THE OFFICIAL
TRACK FORECAST IS CLOSE TO A CONSENSUS OF THE GLOBAL MODELS...WHICH
ARE WELL TO THE SOUTH AND WEST OF THE GFDL AND HWRF.  THESE LATTER
MODELS ARE PREDICTING RINA TO BECOME A STRONG HURRICANE THAT WOULD
RESPOND TO THE DEEP-LAYER SOUTHWESTERLY FLOW OVER THE EASTERN GULF. 
GIVEN THE PREDICTED ATMOSPHERIC ENVIRONMENT...SUCH A SCENARIO SEEMS
UNLIKELY AT THIS TIME.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  24/0900Z 16.7N  82.3W   35 KT  40 MPH
 12H  24/1800Z 17.0N  82.9W   40 KT  45 MPH
 24H  25/0600Z 17.4N  83.6W   45 KT  50 MPH
 36H  25/1800Z 17.5N  84.3W   50 KT  60 MPH
 48H  26/0600Z 17.6N  85.0W   55 KT  65 MPH
 72H  27/0600Z 18.5N  86.5W   60 KT  70 MPH
 96H  28/0600Z 19.5N  87.0W   65 KT  75 MPH
120H  29/0600Z 20.5N  87.0W   65 KT  75 MPH
 
$$
FORECASTER PASCH/LANDSEA