000
WTNT41 KNHC 290839
TCDAT1
 
TROPICAL STORM ARLENE DISCUSSION NUMBER   3
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL012011
400 AM CDT WED JUN 29 2011
 
THUNDERSTORM COVERAGE HAS INCREASED MARKEDLY NEAR AND TO THE
SOUTHEAST OF THE CENTER OF ARLENE DURING THE PAST SEVERAL HOURS. 
HOWEVER...A TRMM MICROWAVE PASS AT 0502 UTC DID NOT SHOW MUCH IN
THE WAY OF ORGANIZATION NEAR THE CENTER...WITH A LACK OF PROMINENT
BANDING. SATELLITE INTENSITY ESTIMATES SUPPORT AN INTENSITY OF
ABOUT 35 KT...SO THAT WILL REMAIN THE INITIAL WIND SPEED.  AN AIR
FORCE RESERVE RECONNAISSANCE AIRCRAFT IS SCHEDULED TO INVESTIGATE
ARLENE LATER THIS MORNING TO PROVIDE MORE INFORMATION ON THE
STRUCTURE AND INTENSITY OF THE CYCLONE. 
 
UPPER-LEVEL CLOUD MOTIONS SUGGEST THAT THE SHEAR IS DECREASING...AND
GIVEN AN INCREASINGLY FAVORABLE ENVIRONMENT...IT SEEMS LIKE IT IS
ONLY A MATTER OF TIME BEFORE ARLENE STRENGTHENS. THE BULK OF THE
INTENSITY GUIDANCE SHOWS THE SYSTEM AS A MODERATE TROPICAL STORM
BEFORE LANDFALL...THOUGH THE HWRF HAS THE SYSTEM BRIEFLY AS A
HURRICANE.  GIVEN THE LARGE SIZE OF ARLENE AND THE LACK OF ANY
INNER CORE FEATURES...HURRICANE STRENGTH APPEARS UNLIKELY...AND THE
NHC FORECAST WILL STAY CLOSE TO THE INTENSITY MODEL CONSENSUS AND
THE PREVIOUS FORECAST.
 
OVERNIGHT MICROWAVE IMAGERY HAS NOT PROVIDED A DEFINITIVE CENTER
POSITION...HOWEVER GEOSTATIONARY IMAGERY SUGGESTS THAT ARLENE IS
STILL MOVING TOWARD THE WEST-NORTHWEST AT ABOUT 7 KT...OR EVEN A
BIT FASTER THAN THAT DURING THE PAST FEW HOURS.  A WESTWARD TURN IS
EXPECTED LATER TODAY AS ARLENE IS STEERED AROUND A STRONG RIDGE
OVER THE SOUTH-CENTRAL UNITED STATES.  THE CYCLONE COULD EVEN MOVE
A LITTLE SOUTH OF WEST TOMORROW DUE TO THE POSITIONING OF THE
RIDGE...AS SUGGESTED BY A FEW GLOBAL MODELS.  THE NEW FORECAST IS
BASICALLY AN UPDATE OF THE PREVIOUS ONE...SHOWING LANDFALL IN A
LITTLE OVER 24 HOURS.
 
GIVEN THE LARGE SIZE OF THE CIRCULATION OF ARLENE...ONE SHOULD NOT
FOCUS ON THE EXACT FORECAST TRACK...AS IMPACTS WILL LIKELY BE FELT
OVER A LARGE PORTION OF NORTHEASTERN MEXICO WELL AWAY FROM THE
CENTER.
 

FORECAST POSITIONS AND MAX WINDS
 
INIT  29/0900Z 21.8N  95.0W   35 KT  40 MPH
 12H  29/1800Z 22.1N  95.9W   40 KT  45 MPH
 24H  30/0600Z 22.1N  97.1W   50 KT  60 MPH
 36H  30/1800Z 22.0N  98.2W   40 KT  45 MPH...INLAND
 48H  01/0600Z 21.8N  99.4W   25 KT  30 MPH...POST-TROP/REMNT LOW
 72H  02/0600Z...DISSIPATED
 
$$
FORECASTER BLAKE/BRENNAN
 

000
WTNT41 KNHC 290839
TCDAT1
 
TROPICAL STORM ARLENE DISCUSSION NUMBER   3
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL012011
400 AM CDT WED JUN 29 2011
 
THUNDERSTORM COVERAGE HAS INCREASED MARKEDLY NEAR AND TO THE
SOUTHEAST OF THE CENTER OF ARLENE DURING THE PAST SEVERAL HOURS. 
HOWEVER...A TRMM MICROWAVE PASS AT 0502 UTC DID NOT SHOW MUCH IN
THE WAY OF ORGANIZATION NEAR THE CENTER...WITH A LACK OF PROMINENT
BANDING. SATELLITE INTENSITY ESTIMATES SUPPORT AN INTENSITY OF
ABOUT 35 KT...SO THAT WILL REMAIN THE INITIAL WIND SPEED.  AN AIR
FORCE RESERVE RECONNAISSANCE AIRCRAFT IS SCHEDULED TO INVESTIGATE
ARLENE LATER THIS MORNING TO PROVIDE MORE INFORMATION ON THE
STRUCTURE AND INTENSITY OF THE CYCLONE. 
 
UPPER-LEVEL CLOUD MOTIONS SUGGEST THAT THE SHEAR IS DECREASING...AND
GIVEN AN INCREASINGLY FAVORABLE ENVIRONMENT...IT SEEMS LIKE IT IS
ONLY A MATTER OF TIME BEFORE ARLENE STRENGTHENS. THE BULK OF THE
INTENSITY GUIDANCE SHOWS THE SYSTEM AS A MODERATE TROPICAL STORM
BEFORE LANDFALL...THOUGH THE HWRF HAS THE SYSTEM BRIEFLY AS A
HURRICANE.  GIVEN THE LARGE SIZE OF ARLENE AND THE LACK OF ANY
INNER CORE FEATURES...HURRICANE STRENGTH APPEARS UNLIKELY...AND THE
NHC FORECAST WILL STAY CLOSE TO THE INTENSITY MODEL CONSENSUS AND
THE PREVIOUS FORECAST.
 
OVERNIGHT MICROWAVE IMAGERY HAS NOT PROVIDED A DEFINITIVE CENTER
POSITION...HOWEVER GEOSTATIONARY IMAGERY SUGGESTS THAT ARLENE IS
STILL MOVING TOWARD THE WEST-NORTHWEST AT ABOUT 7 KT...OR EVEN A
BIT FASTER THAN THAT DURING THE PAST FEW HOURS.  A WESTWARD TURN IS
EXPECTED LATER TODAY AS ARLENE IS STEERED AROUND A STRONG RIDGE
OVER THE SOUTH-CENTRAL UNITED STATES.  THE CYCLONE COULD EVEN MOVE
A LITTLE SOUTH OF WEST TOMORROW DUE TO THE POSITIONING OF THE
RIDGE...AS SUGGESTED BY A FEW GLOBAL MODELS.  THE NEW FORECAST IS
BASICALLY AN UPDATE OF THE PREVIOUS ONE...SHOWING LANDFALL IN A
LITTLE OVER 24 HOURS.
 
GIVEN THE LARGE SIZE OF THE CIRCULATION OF ARLENE...ONE SHOULD NOT
FOCUS ON THE EXACT FORECAST TRACK...AS IMPACTS WILL LIKELY BE FELT
OVER A LARGE PORTION OF NORTHEASTERN MEXICO WELL AWAY FROM THE
CENTER.
 

FORECAST POSITIONS AND MAX WINDS
 
INIT  29/0900Z 21.8N  95.0W   35 KT  40 MPH
 12H  29/1800Z 22.1N  95.9W   40 KT  45 MPH
 24H  30/0600Z 22.1N  97.1W   50 KT  60 MPH
 36H  30/1800Z 22.0N  98.2W   40 KT  45 MPH...INLAND
 48H  01/0600Z 21.8N  99.4W   25 KT  30 MPH...POST-TROP/REMNT LOW
 72H  02/0600Z...DISSIPATED
 
$$
FORECASTER BLAKE/BRENNAN