ZCZC MIATCDEP3 ALL TTAA00 KNHC DDHHMM TROPICAL STORM MIRIAM DISCUSSION NUMBER 18 NWS NATIONAL HURRICANE CENTER MIAMI FL EP132012 200 AM PDT WED SEP 26 2012 THE CONVECTIVE ORGANIZATION OF MIRIAM HAS GONE RAPIDLY DOWNHILL OVER THE PAST SEVERAL HOURS WITH MOST OF THE SIGNIFICANT THUNDERSTORM ACTIVITY NORTH OF THE CENTER. THE CENTRAL DENSE OVERCAST HAS ALSO BECOME RATHER ELONGATED...AND AN EARLIER EYE FEATURE IS NO LONGER APPARENT ON MICROWAVE DATA. SATELLITE INTENSITY ESTIMATES RANGE FROM 55-72 KT...AND GIVEN THE POOR SATELLITE APPEARANCE...THE INITIAL WIND SPEED IS LOWERED TO 60 KT. CONTINUED WEAKENING IS LIKELY DUE TO MODERATE OR STRONG SOUTHWESTERLY SHEAR...GRADUALLY COOLING SSTS...AND ENTRAINMENT OF A MORE STABLE AIRMASS. THE NEW FORECAST IS CLOSE TO A BLEND OF THE PREVIOUS ONE AND THE INTENSITY CONSENSUS. AN UNCERTAIN INITIAL MOTION ESTIMATE IS 320/5. ALMOST ALL THE GUIDANCE MOVE MIRIAM TO THE NORTH OR NORTH-NORTHWEST TODAY IN RESPONSE TO A DIGGING TROUGH SEEN ALONG 120W IN WATER VAPOR IMAGES. AS THE TROUGH DROPS SOUTH OF THE TROPICAL CYCLONE IN A DAY OR TWO...MIRIAN WILL PROBABLY TURN TO THE NORTHWEST. THE OFFICIAL FORECAST IS BASICALLY AN UPDATE OF THE PREVIOUS ONE...CLOSE TO THE FSU SUPERENSEMBLE...THROUGH 48 HOURS. AFTER THAT TIME...LITTLE MOTION IS INDICATED AS THE WEAK REMNANT SYSTEM WILL BE POSITIONED IN LIGHT STEERING CURRENTS. FORECAST POSITIONS AND MAX WINDS INIT 26/0900Z 19.5N 115.5W 60 KT 70 MPH 12H 26/1800Z 20.3N 115.7W 50 KT 60 MPH 24H 27/0600Z 21.5N 116.0W 45 KT 50 MPH 36H 27/1800Z 22.4N 116.4W 35 KT 40 MPH 48H 28/0600Z 22.9N 116.6W 30 KT 35 MPH...POST-TROP/REMNT LOW 72H 29/0600Z 23.2N 116.8W 25 KT 30 MPH...POST-TROP/REMNT LOW 96H 30/0600Z 23.5N 117.0W 20 KT 25 MPH...POST-TROP/REMNT LOW 120H 01/0600Z...DISSIPATED $$ FORECASTER BLAKE 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: Monday, 31-Dec-2012 12:10:38 UTC