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Hurricane OTIS (Text)

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HURRICANE OTIS DISCUSSION NUMBER  10
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
8 AM PDT FRI SEP 30 2005
 
THE EYE HAS BECOME CLOUD-COVERED IN VISIBLE IMAGERY... BUT THE EYE
STRUCTURE HAS CONTINUED TO IMPROVE BASED ON RECENT MICROWAVE
SATELLITE IMAGERY AND RADAR DATA FROM CABO SAN LUCAS MEXICO. THE
INITIAL INTENSITY OF 70 KT IS BASED ON A BLEND OF SATELLITE
INTENSITY ESTIMATES OF 77 KT FROM TAFB...65 KT FROM SAB... 65 KT
FROM AFWA... AND AN AVERAGE ODT VALUE OF T4.5/77 KT OVER THE PAST
1.5 HOURS. THE CONVECTIVE BANDING CONTINUES TO IMPROVE AND OUTFLOW
IS GOOD TO EXCELLENT IN ALL QUADRANTS.
 
THE INITIAL MOTION ESTIMATE IS 325/07. OTIS MADE A SLIGHT WESTWARD
JOG DURING THE PAST 6 HOURS... BUT THIS IS BELIEVED TO BE A
TEMPORARY MOTION AND WAS LIKELY DUE TO THE RE-ALIGNMENT OF THE MID-
AND LOW-LEVEL CIRCULATION CENTERS. A 30/0532Z TRMM OVERPASS
INDICATED THE MID-LEVEL EYE FEATURE WAS TILTED ABOUT 20 NMI TO THE
EAST OF THE LOW-LEVEL EYE... BUT RADAR DATA AND A 30/1205Z AMSU
OVERPASS SUGGEST THAT THE TWO CIRCULATIONS ARE NOW VERTICALLY
STACKED. THE OFFICIAL FORECAST TRACK AND REASONING REMAINS
ESSENTIALLY UNCHANGED. OTIS IS EXPECTED TO CONTINUE TO MOVE
NORTHWESTWARD AROUND THE WEAKENING WESTERN PORTION OF A LARGE
SUBTROPICAL RIDGE LOCATED OVER NORTHERN MEXICO FOR THE NEXT 48
HOURS. AFTER THAT... HOWEVER... THERE IS CONSIDERABLE DIVERGENCE IN
THE MODEL GUIDANCE ON HOW THE UPPER-LOW OFF THE CALIFORNIA COAST IS
HANDLED. THE GFS... NOGAPS... AND UKMET MODELS DROP THE LOW
SOUTHEASTWARD TO THE WEST AND SOUTHWEST OF OTIS... WHICH RESULTS IN
THE HURRICANE BEING LIFTED NORTHWARD ACROSS BAJA AND THEN
NORTHEASTWARD ACROSS EXTREME NORTHWESTERN MEXICO AND THE
SOUTHWESTERN UNITED STATES. IN CONTRAST... THE GFDL... CANADIAN...
AND ECMWF MODELS WEAKEN THE UPPER-LOW AND BUILD THE RIDGE TO THE
NORTH OF OTIS... CAUSING THE CYCLONE TO TURN SLOWLY WESTWARD AWAY
FROM BAJA CALIFORNIA. THE LATEST TREND IN WATER VAPORY IMAGERY AND
IN UW-CIMSS WATER VAPOR-DERIVED WINDS INDICATE THAT THE UPPER-LOW
IS STRONGER... DIGGING SOUTHWARD... AND THAT MORE RIDGING IS
OCCURRING TO THE NORTH AND WEST OF THE UPPER-LOW. ALSO... 500 MB
HEIGHTS HAVE DECREASED MORE THAN 40 METERS DURING THE PAST 24 HOURS
ALONG THE CENTRAL AND SOUTHERN CALIFORNIA COASTS AND OVER SOUTHERN
BAJA. ALL OF THIS WOULD TEND TO SUPPORT THE GFS-NOGAPS-UKMET
SOLUTION... AND THAT 3-MODEL CONSENSUS WAS CLOSELY FOLLOWED.

SOME ADDITIONAL STRENGTHENING IS FORECAST FOR THE NEXT 24 HOURS
SINCE OTIS IS EXPECTED TO REMAIN OVER 28C OR WARMER SSTS AND THE
VERTICAL SHEAR IS FORECAST TO REMAIN 5 KT OR LESS. THE INTENSITY
FORECAST IS CLOSE TO THE SHIPS AND GFDL MODELS THROUGH 72 HOURS.
 
THE FORECAST TRACK AND WIND RADII KEEP THE STRONGER WINDS OFFSHORE.
HOWEVER...ANY DEVIATION TO THE RIGHT COULD BRING STRONGER WINDS TO
THE SOUTHWEST PORTION OF BAJA CALIFORNIA LATER TODAY OR SATURDAY.
 
FORECASTER STEWART
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      30/1500Z 21.1N 110.7W    70 KT
 12HR VT     01/0000Z 21.8N 111.4W    75 KT
 24HR VT     01/1200Z 22.5N 111.8W    80 KT
 36HR VT     02/0000Z 23.5N 112.4W    75 KT
 48HR VT     02/1200Z 24.5N 113.0W    70 KT
 72HR VT     03/1200Z 26.0N 113.5W    60 KT
 96HR VT     04/1200Z 28.5N 113.5W    45 KT...INLAND CENTRAL BAJA
120HR VT     05/1200Z 31.5N 112.0W    30 KT...INLAND NWRN MEXICO
 
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