ZCZC MIATCDEP2 ALL TTAA00 KNHC DDHHMM TROPICAL DEPRESSION GREG DISCUSSION NUMBER 18 NWS NATIONAL HURRICANE CENTER MIAMI FL EP072011 800 PM PDT SAT AUG 20 2011 A SMALL AREA OF DEEP CONVECTION HAS PERSISTED ON THE NORTHEASTERN EDGE OF THE CENTER OF GREG OVER THE PAST 12 HOURS. SATELLITE CURRENT INTENSITY ESTIMATES ARE 35 AND 30 KT FROM TAFB AND SAB... RESPECTIVELY...WHILE BOTH AGENCIES REPORTED A FINAL T-NUMBER INTENSITY OF 25 KT. THE INITIAL INTENSITY OF 30 KT IS AN AVERAGE OF THE DVORAK NUMBERS...AND GREG IS DOWNGRADED TO A TROPICAL DEPRESSION ON THIS ADVISORY. THE INITIAL MOTION IS 285/06. GREG WILL BE STEERED ON A WEST-NORTHWEST TRACK TONIGHT BY THE NORTHEAST PACIFIC SUBTROPICAL HIGH AND ITS ASSOCIATED SURFACE RIDGE. THE SURFACE RIDGE IS WEAKENING AS A MID- TO UPPER-LEVEL TROUGH DIGS OFF THE WEST COAST... WHICH WILL LIKELY ALLOW GREG TO DRIFT SLIGHTLY FARTHER NORTH THAN EARLIER ANTICIPATED. AS GREG WEAKENS AND BECOMES INCREASINGLY SHALLOW IT SHOULD BE STEERED TOWARD THE WEST BY THE SURFACE RIDGE ON SUNDAY AND THEN TOWARD THE WEST-SOUTHWEST SUNDAY NIGHT AND MONDAY. THE FORECAST TRACK HAS BEEN NUDGED TO THE NORTH AGAIN AND IS ESSENTIALLY DOWN THE MIDDLE OF THE GUIDANCE ENVELOPE. GREG WILL CONTINUE WEAKENING OVER COOL WATERS. SSTS WILL REMAIN IN THE RATHER COLD 22C TO 23C RANGE DURING THE NEXT COUPLE OF DAYS... AND STABLE AIR WILL CONTINUE TO BE INGESTED FROM THE NORTH. AS A RESULT...GREG IS FORECAST TO SPIN DOWN TO A REMNANT LOW PRESSURE SYSTEM ON SUNDAY. FORECAST POSITIONS AND MAX WINDS INIT 21/0300Z 20.1N 121.0W 30 KT 35 MPH 12H 21/1200Z 20.2N 122.0W 25 KT 30 MPH 24H 22/0000Z 20.1N 123.4W 25 KT 30 MPH...POST-TROP/REMNT LOW 36H 22/1200Z 19.6N 124.9W 25 KT 30 MPH...POST-TROP/REMNT LOW 48H 23/0000Z 19.0N 126.3W 20 KT 25 MPH...POST-TROP/REMNT LOW 72H 24/0000Z...DISSIPATED $$ FORECASTER WROE/BRENNAN NNNN
Alternate Formats
About Alternates -
E-Mail Advisories -
RSS Feeds
Cyclone Forecasts
Latest Advisory -
Past Advisories -
About Advisories
Marine Forecasts
Latest Products -
About Marine Products
Tools & Data
Satellite Imagery -
US Weather Radar -
Aircraft Recon -
Local Data Archive -
Forecast Verification -
Deadliest/Costliest/Most Intense
Learn About Hurricanes
Storm Names
Wind Scale -
Prepare -
Climatology -
NHC Glossary -
NHC Acronyms -
Frequently Asked Questions -
AOML Hurricane-Research Division
About Us
About NHC -
Mission/Vision -
Other NCEP Centers -
NHC Staff -
Visitor Information -
NHC Library
NOAA/
National Weather Service
National Centers for Environmental Prediction
National Hurricane Center
11691 SW 17th Street
Miami, Florida, 33165-2149 USA
nhcwebmaster@noaa.gov
Disclaimer
Privacy Policy
Credits
About Us
Glossary
Career Opportunities
Page last modified: Tuesday, 17-Jul-2012 13:44:15 UTC