Tropical Storm LAURA

ZCZC MIATCDAT2 ALL
TTAA00 KNHC DDHHMM
TROPICAL STORM LAURA DISCUSSION NUMBER   7
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL122008
500 PM EDT TUE SEP 30 2008
 
A 1653 UTC CIMSS AMSU INTENSITY ESTIMATE CONFIRMS THAT LAURA STILL
HAS MAXIMUM WINDS OF 50 KT. IN ADDITION...THE SATELLITE
PRESENTATION OF THE STORM'S CENTRAL FEATURES HAS NOT CHANGED
APPRECIABLY SINCE THIS MORNING SO THERE IS LITTLE REASON TO CHANGE
THE INITIAL INTENSITY.  ALTHOUGH LAURA IS CURRENTLY A TROPICAL
CYCLONE...VISIBLE IMAGERY SUGGESTS THAT SOME THERMAL ADVECTION IS
BEGINNING TO OCCUR AS COLD AIR STRATUS CLOUDS WRAP AROUND THE WEST
SIDE OF THE CIRCULATION.  GLOBAL MODEL FIELDS INDICATE THAT THE
EXTRATROPICAL TRANSITION PROCESS WILL CONTINUE THROUGH TONIGHT...
AND LAURA COULD BE FULLY NON-TROPICAL IN 18-24 HOURS. THE SYSTEM IS
NOW OVER SEA SURFACE TEMPERATURES NEAR 21C AND IS QUICKLY LOSING
ITS TROPICAL ENERGY SOURCE...SO SOME WEAKENING IS SHOWN IN THE
OFFICIAL FORECAST OVER THE NEXT 36 HOURS.  THEREAFTER...BAROCLINIC
FORCING WILL BECOME MORE PROMINENT AS THE EXTRATROPICAL LOW BECOMES
EMBEDDED IN THE WESTERLIES...AND SOME RE-STRENGTHENING COULD OCCUR.

LAURA IS NOW MOVING JUST EAST OF DUE NORTH AT 010/12.  MOST OF THE
TRACK GUIDANCE IS TIGHTLY CLUSTERED THROUGH 5 DAYS AND THE OFFICIAL
FORECAST REMAINS VERY CLOSE TO THE MODEL CONSENSUS.  THE NHC
FORECAST TRACK SHOWS A SLIGHT WESTWARD BEND AT 36-48 HOURS DUE TO
THE INFLUENCE OF A SHORTWAVE TROUGH OVER THE CANADIAN
MARITIMES...BUT AFTER THAT LAURA IS ACCELERATED EASTWARD ACROSS THE
NORTH ATLANTIC.  A 120-HOUR POSITION IS NOT GIVEN IN THIS FORECAST
SINCE IT WOULD BE LOCATED EAST OF THE PRIME MERIDIAN OVER THE NORTH
SEA...AND THE LOW COULD BE ABSORBED BY A FRONTAL BOUNDARY BY THEN
ANYWAY.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      30/2100Z 42.3N  48.6W    50 KT
 12HR VT     01/0600Z 44.0N  48.0W    45 KT...BECOMING EXTRATROPICAL
 24HR VT     01/1800Z 46.8N  46.8W    40 KT...EXTRATROPICAL
 36HR VT     02/0600Z 50.0N  45.1W    40 KT...EXTRATROPICAL
 48HR VT     02/1800Z 53.1N  42.4W    45 KT...EXTRATROPICAL
 72HR VT     03/1800Z 56.5N  31.5W    45 KT...EXTRATROPICAL
 96HR VT     04/1800Z 57.0N  17.0W    45 KT...EXTRATROPICAL
120HR VT     05/1800Z...ABSORBED
 
$$
FORECASTER BERG/PASCH
 
NNNN