000
WTPZ45 KNHC 192035
TCDEP5
HURRICANE RICK DISCUSSION NUMBER  18
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP202009
200 PM PDT MON OCT 19 2009
 
DATA FROM AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT INDICATE
THAT RICK HAS WEAKENED QUICKLY. THE MAXIMUM FLIGHT LEVEL WIND OF 76
KT WAS FOUND IN THE NORTHEASTERN QUADRANT...WHILE THE PEAK SFMR
WIND WAS 68 KT. THE INITIAL INTENSITY IS HELD CONSERVATIVELY AT
85 KT FOR THIS PACKAGE...SINCE THE AIRCRAFT DID NOT SAMPLE SOME OF
THE DEEPER CONVECTION LOCATED ABOUT 50 MI EAST OF THE CENTER. DATA
FROM THE AIRCRAFT ALSO SUGGEST THAT THE 50-KT AND 34-KT WIND FIELDS
HAVE EXPANDED...ESPECIALLY IN THE NORTHEASTERN QUADRANT...AS THE
PREVIOUSLY TIGHT PRESSURE GRADIENT IN THE INNER CORE BEGINS TO
RELAX.
 
THE SHIPS MODEL AND UW-CIMSS ANALYSES CONTINUE TO SHOW 15 TO 20 KT
OF WEST-SOUTHWESTERLY SHEAR OVER RICK. THE SHIPS FORECASTS THIS TO
PERSIST FOR MOST OF THE NEXT 36 HOURS BEFORE INCREASING EVEN
FURTHER. THE CYCLONE WILL ALSO BE MOVING INTO A DRIER MID-LEVEL
ENVIRONMENT AFTER 24 HOURS. THIS SHOULD RESULT IN A STEADY
WEAKENING OF THE CYCLONE. THE OFFICIAL FORECAST IS AGAIN ADJUSTED
DOWNWARD IN AGREEMENT WITH THE ICON INTENSITY CONSENSUS THROUGH 24
HOURS...AND THEN LEANS TOWARD THE SHIPS AND LGEM BEYOND THAT TIME.
THE STATISTICAL MODELS SHOW CONTINUED WEAKENING...WHILE THE GFDL
AND HWRF HOLD THE INTENSITY STEADY OR EVEN SHOW STRENGTHENING ON
DAY 2...WHICH SEEMS UNREALISTIC CONSIDERING THE ENVIRONMENT THAT
RICK WILL BE MOVING INTO.
 
THE INITIAL MOTION ESTIMATE IS NOW TOWARD THE NORTH-NORTHWEST...
330/06. THE TRACK GUIDANCE CONTINUES TO BE IN GOOD AGREEMENT ON RICK
ACCELERATING TOWARD THE NORTH AND THEN TOWARD THE NORTHEAST AS IT
RECURVES AHEAD OF A MID-LEVEL TROUGH THAT WILL BE MOVING INTO THE
SOUTHWESTERN UNITED STATES IN THE NEXT COUPLE OF DAYS. THE
MULTI-MODEL CONSENSUS...TVCN HAS CONTINUED TO SHIFT TO THE EAST...
AND THE OFFICIAL FORECAST IS AGAIN NUDGED IN THAT DIRECTION.

FORECAST POSITIONS AND MAX WINDS
 
INITIAL      19/2100Z 18.5N 111.7W    85 KT
 12HR VT     20/0600Z 19.2N 111.8W    75 KT
 24HR VT     20/1800Z 20.4N 111.1W    65 KT
 36HR VT     21/0600Z 21.9N 109.9W    55 KT
 48HR VT     21/1800Z 23.5N 108.2W    50 KT
 72HR VT     22/1800Z 25.5N 106.0W    20 KT...DISSIPATING INLAND
 96HR VT     23/1800Z...DISSIPATED
 
$$
FORECASTER BRENNAN/ROBERTS