000
AXPZ20 KNHC 182119
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC SUN OCT 18 2009

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. 

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2100 UTC.

...SPECIAL FEATURE... 

EXTREMELY DANGEROUS HURRICANE RICK CENTERED NEAR 16.4N 109.4W AT 
18/2100 UTC...OR ABOUT 400 NM S OF THE TIP OF BAJA CALIFORNIA... 
MOVING WNW AT 12 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 921 
MB. MAXIMUM SUSTAINED WIND SPEED IS 140 KT WITH GUSTS TO 170 KT. 
THE EYE DIAMETER IS ABOUT 20 NM. RICK IS SLOWLY WEAKENING AS 
INDICATING BY WARMING CLOUD TOPS SURROUNDING THE EYE AND IS MOST 
EVIDENT OVER THE W QUADRANT. SHEAR IS FORECAST TO INCREASE IN 
ABOUT TWO DAYS BUT RICK IS STILL EXPECTED TO ENTER THE SOUTHERN 
BAJA CALIFORNIA PENINSULA AS A HURRICANE. RICK IS CURRENTLY 
BEING STEERED BY A MIDDLE/UPPER LEVEL RIDGE LOCATED OVER MEXICO. 
NUMEROUS STRONG CONVECTION IS LOCATED WITHIN 90 NM OF THE 
CENTER...EXCEPT 50 NM OVER THE W QUADRANT. SEE LATEST NHC 
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP5/WTPZ25 KNHC 
FOR MORE DETAILS.

...TROPICAL WAVES...

A TROPICAL WAVE IS LOCATED ALONG 80W N OF 04N ACROSS PANAMA AND 
INTO THE SW CARIBBEAN. THE WAVE IS MOVING W 10 TO 15 KT. 
SCATTERED MODERATE TO STRONG CONVECTION IS LOCATED N OF 06N E OF 
86W. 

A TROPICAL WAVE IS LOCATED ALONG 123W FROM 06N TO 16N AND IS 
MOVING W 10 TO 15 KT. THE WAVE IS WEAK AND MINIMAL CONVECTION IS 
ASSOCIATED WITH IT. 

...ITCZ...

THE AXIS OF THE INTERTROPICAL CONVERGENCE ZONE IS CENTERED ALONG 
09N84W TO 07N90W TO 12N103W AND THEN CONTINUES FROM 13N111W TO 
13N122W TO 14N130W TO 11N140W. SCATTERED MODERATE ISOLATED 
STRONG CONVECTION IS LOCATED WITHIN A 60 NM RADIUS OF 12N120W.

...DISCUSSION...

W OF 115W...
A MIDDLE/UPPER LEVEL TROUGH IS LOCATED ROUGHLY N OF 23N W OF 
123W WITH THE AXIS ALONG 128W. MODERATE SW WINDS ARE LOCATED 
ON THE E SIDE OF THE TROUGH WITH SATELLITE CLOUD DRIFT WINDS 
INDICATING SPEEDS OF 40 TO 50 KT. FLOW IS EVEN STRONGER N OF 29N 
W OF 132W WITH WATER VAPOR IMAGERY INDICATING WEST NORTHWESTERLY 
FLOW IN THIS AREA. IN ABOUT TWO DAYS THE TROUGH AXIS IS EXPECTED 
TO BECOME ORIENTED ALONG 117W/118W N OF 18N AND WILL ACT TO TURN 
RICK IN A MORE NORTHERLY DIRECTION AND THEN TO THE NE INTO 
MEXICO. GENERALLY MODERATE EASTERLY FLOW ALOFT IS LOCATED OVER 
THE TROPICS S OF ABOUT 15N. AT THE SURFACE A 1024 MB HIGH IS 
LOCATED NEAR 31N135W.  

E OF 115W...
WINDS ALOFT ARE GENERALLY NORTHEASTERLY BETWEEN 90W AND 100W AND 
BECOME MORE EASTERLY E OF 90W INTO CENTRAL AND SOUTH AMERICA. AT 
THE SURFACE A STORM WARNING IS FORECAST OVER THE GULF OF 
TEHUANTEPEC.

$$
CAB