000
AXPZ20 KNHC 192153
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC SAT AUG 19 2006

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. THE FOLLOWING INFORMATION IS 
BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND 
METEOROLOGICAL ANALYSIS.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2145 UTC.

...SPECIAL FEATURES...
HURRICANE HECTOR AT 18.3N 131.0W 979 MB AT 2100 UTC AUG 19 
MOVING WNW OR 295 DEG AT 11 KT. MAXIMUM SUSTAINED WINDS 75 KT 
GUSTS 90 KT. NUMEROUS STRONG CONVECTION IS NOTED WITHIN 90 NM OF 
CENTER WITH A FAINT EYE BREAKING THROUGH THE CENTRAL DENSE 
OVERCAST. HECTOR IS ENCOUNTERING NW SHEAR AND DRY AIR 
ENTRAINMENT OVER ITS SW QUAD. A STEADY WEAKENING IS FORECAST 
TONIGHT THEN QUICKER WEAKENING IS EXPECTED ON SUN AS HECTOR 
MOVES OVER COOLER SEA SURFACE WATERS AND EXPERIENCES INCREASING 
W WIND SHEAR. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO 
HEADERS MIATCMEP4/WTPZ24 KNHC FOR MORE DETAILS. 

...TROPICAL WAVES...
A TROPICAL WAVE ALONG 95.5W TO THE N OF 5N IS MOVING W AT AN 
ESTIMATED 15 KT. BROAD CYCLONIC TURNING IS NOTED WITH SCATTERED 
MODERATE AND STRONG CONVECTION ENHANCED ALONG 10.5N BETWEEN 97W 
AND 101W...SURROUNDED BY SCATTERED MODERATE ISOLATED STRONG N OF 
5N TO THE MEXICAN BETWEEN 91N AND 103W. GLOBAL MODELS GRADUALLY 
SPIN UP A CYCLONE ALONG THIS WAVE OVER THE NEXT FEW DAYS...BUT 
NO ORGANIZED BANDING CAN BE MEASURED AT THE MOMENT.    

A TROPICAL WAVE ALONG 119.5W FROM 3N TO 15N IS MOVING W AT AN 
ESTIMATED 12 KT. ONLY ISOLATED SHOWERS ACCOMPANY THE WAVE AT THE 
MOMENT.

...ITCZ...
THE ITCZ AXIS IS CENTERED ALONG 7N77W 10N86W 10N96W 9N110W 
9N121W 14N130W 10N140W. SCATTERED MODERATE ISOLATED STRONG 
CONVECTION IS NOTED WITHIN 180 NM EITHER SIDE OF LINE 5N80W 
10N94W...AND FROM 6N TO 15N BETWEEN 94W AND 103W...AND FROM 6N 
TO 12N BETWEEN 104W AND 117W...AND WITHIN 90 NM OF 10N140W. 

...DISCUSSION...
A SHORTWAVE TROUGH IS SWING SE THROUGH THE UPPER LEVELS WITH ITS 
AXIS CURRENTLY ALONG 32N136W 23N134W. NW WINDS TO THE W OF THE 
TROUGH IS PARTIALLY RESPONSIBLE FOR THE NE SHEAR THAT HURCN 
HECTOR IS EXPERIENCING. A SECOND SHORTWAVE IS NOTED ALONG 
32N123W 25N120W. THE ANTICYCLONE ASSOCIATED WITH HECTOR RIDGES N 
ALONG 126W TO A GENTLE CREST ALONG 30N BETWEEN 130W AND 
124W...AND EFFECTIVELY SEPARATES THE TWO SHORTWAVE TROUGHS. 

ANOTHER ANTICYCLONE IS NOTED JUST W OF THE DISCUSSION AREA NEAR 
16N144W RIDGING NE TO A CREST AT 20N137W...WITH THE ANTICYCLONIC 
FLOW MERGING NEAR 22N140W WITH THE CYCLONIC FLOW BEHIND THE 
UPPER TROUGH...ALL BECOMING NW SHEAR INTO HECTOR.
     
TO THE SE OF HECTOR...AN UPPER LEVEL CYCLONE IS OBSERVED NEAR 
14N113W AND IS SLIPPING W WITH TIME AS MODELS SUGGEST. AN UPPER 
INVERTED TROUGH EXTEND N FROM THE CYCLONE TO THE SRN TIP OF THE 
BAJA PENINSULA. ANOTHER SMALL UPPER CYCLONE IS OBSERVED NEAR 
22N97W AND IS ALSO MOVING W WITH TIME...WITH AN UPPER TROUGH 
EXTENDING SE TO ANOTHER UPPER CYCLONE OVER THE CARIBBEAN NEAR 
17N80W.  AN UPPER RIDGE SEPARATES THESE CYCLONES...WITH THE 
SMALL ANTICYCLONIC CENTER NOTED NEAR 20N105W. A RIDGE EXTENDS SE 
ALONG 15N96W TO ANOTHER UPPER ANTICYCLONE AT 15N95W.

UPPER MOISTURE...ORIGINATING FROM ITCZ CONVECTION THROUGHOUT THE 
DISCUSSION AREA AND FROM HURCN HECTOR...IS NOTED SE OF LINE 
14N140W 24N134W 30N113W. MODERATE DRY AIR UPPER IS NOTED NW OF 
THE SAME LINE. 
 
AT THE SURFACE...A RIDGE EXTENDS SE ALONG 32N132W TO 20N113W 
WITH NW WINDS SURGING TO 20 KT OVER THE WATERS N OF 25N ALONG 
THE W COAST OF THE BAJA PENINSULA. 

$$
NELSON