Tropical Depression MIRIAM

ZCZC MIATCDEP3 ALL
TTAA00 KNHC DDHHMM
 
TROPICAL DEPRESSION MIRIAM DISCUSSION NUMBER  24
NWS NATIONAL HURRICANE CENTER MIAMI FL       EP132012
200 PM PDT THU SEP 27 2012
 
CONVENTIONAL SATELLITE IMAGERY INDICATES THAT THE LAST BIT OF DEEP
CONVECTION DISSIPATED AROUND 1200 UTC THIS MORNING.  A 1708 UTC
ASCAT OVERPASS INDICATED A FEW WIND VECTORS JUST BELOW
TROPICAL STORM FORCE IN THE SOUTHWEST QUADRANT.  GIVEN THE LACK OF
DEEP CONVECTION...THE CIRCULATION HAS LIKELY BEEN GRADUALLY
WEAKENING DURING THE DAY.  THEREFORE...THE SYSTEM IS BEING
CLASSIFIED AS A TROPICAL DEPRESSION...AND THE INITIAL
INTENSITY SET AT 30 KT.  SUBSEQUENTLY...DEEP CONVECTION IS NOT
EXPECTED TO REDEVELOP SINCE THE DEPRESSION WILL REMAIN OVER SEA
SURFACE TEMPERATURES OF LESS THAN 25C AND IN AN ENVIRONMENT
CONSISTING OF 25-30 KT OF SOUTHWESTERLY WIND SHEAR AND A
SURROUNDING STABLE AIR MASS.  MIRIAM IS EXPECTED TO BECOME A
POST-TROPICAL REMNANT LOW TONIGHT...WITH DISSIPATION OCCURRING IN 3
DAYS OR LESS.
 
THE INITIAL MOTION ESTIMATE IS 270/4...AND THIS GENERAL MOTION
SHOULD PERSIST THROUGH EARLY FRIDAY MORNING.  AFTERWARD...THE
REMNANT LOW IS FORECAST TO GRADUALLY TURN TOWARD THE SOUTHWEST AND
THEN DRIFT SOUTHWARD AROUND THE 36 HOUR PERIOD IN THE
EAST-NORTHEASTERLY TRADEWIND STEERING FLOW.  THE NHC FORECAST IS
SIMILAR TO THE PREVIOUS ADVISORY AND IS BASED ON THE TVCE
MULTI-MODEL CONSENSUS.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  27/2100Z 22.1N 116.9W   30 KT  35 MPH
 12H  28/0600Z 22.0N 117.2W   30 KT  35 MPH...POST-TROP/REMNT LOW
 24H  28/1800Z 21.7N 117.2W   25 KT  30 MPH...POST-TROP/REMNT LOW
 36H  29/0600Z 21.4N 117.0W   20 KT  25 MPH...POST-TROP/REMNT LOW
 48H  29/1800Z 21.2N 116.9W   20 KT  25 MPH...POST-TROP/REMNT LOW
 72H  30/1800Z...DISSIPATED
 
$$
FORECASTER ROBERTS
 
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