Hurricane NORBERT

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HURRICANE NORBERT DISCUSSION NUMBER  28
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP152008
200 PM PDT FRI OCT 10 2008
 
UNFORTUNATELY THE AIR FORCE RESERVE HURRICANE HUNTER FLIGHT THAT WAS
SCHEDULED FOR TODAY HAD TO BE CANCELED DUE TO AN EQUIPMENT PROBLEM.
NONETHELESS...SATELLITE INTENSITY ESTIMATES FROM TAFB AND SAB ARE
NOW 90 KT AND 102 KT RESPECTIVELY...SO THE INITIAL INTENSITY IS
RAISED CONSERVATIVELY TO 90 KT. YESTERDAY'S HURRICANE HUNTER FLIGHT
INDICATED THAT THE MAXIMUM WINDS WERE NOT AS STRONG AS THE
SATELLITE SIGNATURE HAD SUGGESTED...SO I AM LOATH TO BRING THE
INTENSITY ANY HIGHER THAN THE LOW END OF THE ESTIMATES. MICROWAVE
AND CONVENTIONAL SATELLITE IMAGERY INDICATE THAT THE INNER EYEWALL
HAS PROBABLY COLLAPSED...AND IS NOW ROTATING WITHIN THE LARGE
EYE...SO THE EYEWALL REPLACEMENT MAY BE COMPLETE.

AGAIN...THE FORECAST INTENSITY HAS HAD TO BE NUDGED UPWARD TO
REFLECT THE RECENT STRENGTHENING OF THE SYSTEM. THE NEW FORECAST
FOLLOWS THE SHIPS AND LGEM MODELS CLOSELY WITHIN THE FIRST 24 HOURS
AND SHOWS A SLOW WEAKENING AS THE VERTICAL SHEAR BEGINS TO
INCREASE. THE SHIPS GUIDANCE INDICATES THAT SOUTHWESTERLY SHEAR
WILL INCREASE SUBSTANTIALLY TO 30-40 KT BY 36 HOURS AND NEAR 50 KT
BY 48 HOURS...SO NORBERT IS EXPECTED TO WEAKEN QUICKLY AS IT
CROSSES THE BAJA PENINSULA AND THE GULF OF CALIFORNIA. NORBERT IS
FORECAST TO BE A TROPICAL STORM BY THE TIME IT REACHES THE COAST OF
MAINLAND MEXICO...BUT THE WIND SPEED PROBABILITY TABLE INDICATES
THERE IS STILL A 40% CHANCE THAT IT COULD BE A HURRICANE AT THAT
POINT...SO A HURRICANE WATCH WAS REQUIRED FOR THAT AREA. RAPID
WEAKENING IS EXPECTED ONCE NORBERT MAKES ITS SECOND LANDFALL...WITH
THE MID-LEVEL CIRCULATION BEING SHEARED QUICKLY TO THE NORTHEAST
AND THE LOW-LEVEL CENTER PROBABLY BEING BLOCKED OR DESTROYED BY THE
SIERRA MADRES.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      10/2100Z 21.4N 113.4W    90 KT
 12HR VT     11/0600Z 22.9N 113.0W    85 KT
 24HR VT     11/1800Z 24.9N 111.6W    70 KT...INLAND OVER BAJA
 36HR VT     12/0600Z 27.1N 109.8W    60 KT...INLAND
 48HR VT     12/1800Z 28.3N 108.5W    30 KT...INLAND
 72HR VT     13/1800Z...DISSIPATED INLAND
 
$$
FORECASTER BERG/FRANKLIN
 
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