Tropical Storm MIRIAM

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TROPICAL STORM MIRIAM DISCUSSION NUMBER   6
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP142006
800 AM PDT SUN SEP 17 2006
 
MIRIAM CONTINUES TO FEEL THE EFFECTS OF VERTICAL WIND SHEAR AND ALL
OF ITS DEEP CONVECTION IS DISPLACED TO THE SOUTHWEST OF THE EXPOSED
LOW LEVEL CENTER. OBSERVATIONS FROM THE MEXICAN NAVY AT ISLA
CLARION REPORTED MAXIMUM SUSTAINED WINDS NEAR 29 KT AND GUSTS TO 45
KT OVER THE PAST FEW HOURS. BASED ON THESE OBSERVATIONS AND CURRENT
INTENSITY NUMBERS OF 3.0 AND 2.5 FROM TAFB AND SAB RESPECTIVELY...
THE INITIAL INTENSITY IS HELD AT 40 KT. MIRIAM WILL BE MOVING INTO
AN AREA OF INCREASED WIND SHEAR AND COOLER WATERS OVER THE NEXT
COUPLE OF DAYS AS INDICATED BY MOST OF THE GLOBAL MODELS.
THEREFORE...THE OFFICIAL FORECAST CALLS FOR STEADY WEAKENING TO A
REMNANT LOW IN 96 HOURS...CLOSELY FOLLOWING THE SHIPS...GFDL AND
FSU SUPERENSEMBLE.

A 0537 UTC AMSU PASS HELPED TO LOCATE THE CENTER. THE FORWARD 
MOTION IS ONLY 015/4...SINCE MIRIAM IS EMBEDED WITHIN RATHER WEAK
STEERING CURRENTS. HOWEVER...MOST OF THE GUIDANCE SHOWS A TURN MORE
TO NORTH AND THEN NORTHWEST AS A MID-LEVEL RIDGE BUILDS TO THE
NORTHEAST OF THE CYCLONE. THIS FORECAST IS SIMILAR TO BUT NUDGED A
LITTLE TO THE LEFT OF THE PREVIOUS ONE TO BECOME BETTER ALIGNED
WITH MOST OF THE GUIDANCE.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      17/1500Z 19.2N 113.9W    40 KT
 12HR VT     18/0000Z 19.9N 113.7W    40 KT
 24HR VT     18/1200Z 20.7N 113.9W    35 KT
 36HR VT     19/0000Z 21.5N 114.5W    30 KT
 48HR VT     19/1200Z 22.5N 115.3W    30 KT
 72HR VT     20/1200Z 23.5N 116.0W    25 KT...DISSIPATING
 96HR VT     21/1200Z 25.0N 116.5W    20 KT...REMNANT LOW
120HR VT     22/1200Z...DISSIPATED
 
$$
FORECASTER MAINELLI/CANGIALOSI
 
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