000
AXPZ20 KNHC 191551
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1445 UTC.

...SPECIAL FEATURES...
HURRICANE HECTOR AT 17.7N 130.1W AT 1500 UTC MOVING WNW OR 290 
DEG AT 10 KT.  MAXIMUM SUSTAINED WIND SPEED 85 GUSTS TO 105 KT.
WHILE HECTOR'S EYE CLOUDED OVER AT TIMES THE EYE WALL APPEARED 
TO STRENGTHEN AS TOPS GOT COLDER THEREFORE HECTOR'S WINDS WERE 
INCREASED TO 90 KT. 

FOR MORE DETAILS SEE LATEST NHC FORECAST/ 
ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP4/WTPZ24 KNHC FOR MORE 
DETAILS. 

...TROPICAL WAVES...
TROPICAL WAVE ALONG 94W N OF 5N MOVING W 15 KT.  NRN PORTION OF 
WAVE UNDER WEAK UPPER ANTICYCLONIC FLOW FAVORABLE FOR FURTHER 
INTENSIFICATION AS PLENTY OF MOISTURE IS AVAILABLE AND SST 
REMAIN FAVORABLE.  BOTTOM PART OF WAVE REMAINS UNDER WEAK TO  
MODERATE NE SHEAR.  GFS SOLUTION IS MOST AGGRESSIVE WITHIN 24 
HRS WHILE NAM PRESENTS WEAKER VERSION.  ENSEMBLE SOLUTION MUCH 
SLOWER AND NOGAPS WENT OUT FOR AN EARLY LUNCH IN THIS CASE.  
BELIEVE GFS IS OVER DOING THE CASE CONSIDERING IT FOLLOWS 
HECTOR PATH OVER STIRRED UP WATERS...SO MAYBE NAM PRESENTS  
MORE REALISTIC SOLUTION.

TROPICAL WAVE ALONG 117W FROM 4N TO 14N MOVING W ABOUT 10 KT. 
SCATTERED MODERATE CONVECTION DIMINISHING RAPIDLY AS AXIS COMES 
UNDER DRY NE UPPER ENVIRON WITH INCREASING WIND SHEAR.  LITTLE 
DEVELOPMENT EXPECTED FOR NEXT 48 HRS. 

...ITCZ...
ITCZ AXIS IS CENTERED ALONG 7N77W  8N105W  11N140W.
SCATTERED MODERATE TO STRONG WITHIN 60 NM OF 14N93W.  SCATTERED 
MODERATE TO STRONG WITHIN 90 NM OF 9N98W. SCATTERED MODERATE TO 
STRONG WITHIN 90 NM OF AXIS W OF 136W.

SCATTERED MODERATE ISOLATED STRONG CONVECTION WITHIN 120 NM OF 
15N95W. 

...DISCUSSION...
DRY QUASI ZONAL FLOW DOMINATE UPPER LEVELS N OF 25N W OF 120W 
WHILE MID/UPPER LEVEL RIDGE CONTROLS S OF 25N W OF 120W.  WEAK 
NARROW TROUGH DENTS INTO S PORTION OF RIDGE ALONG 129W S OF 
15N.  DOWNSTREAM...UPPER LEVEL CYCLONIC VORTEX AT 15N112W KEEPS 
DRY CONDITIONS ALONG AXIS AFFECTING NEARBY TROPICAL WAVE 
DEVELOPMENT.

MID/UPPER LEVEL RIDGE EXTENDS ALONG COASTAL WATERS OF MEXICO E 
OF 110W THROUGH CENTRAL AMERICA TO COSTA RICA BRINGING PLENTY OF 
TROPICAL MOISTURE LADEN AIR MASS INTO E PAC ALONG ITCZ HELPING 
ITS ACTIVITY.  FAVORABLE UPPER LEVEL FLOW ALSO CONDUCIVE TO 
DEVELOPMENT OF SURFACE FEATURES.     
  
AT THE SURFACE...HIGH PRES RIDGE WELL N OF AREA SQUEEZING 
GRADIENT AGAINST CALIFORNIA COAST INCREASING N-NW WINDS AND SEAS.

CROSS EQUATORIAL S FLOW ADDING PLENTY OF MOISTURE AND INSTABILITY
TO ITCZ ACTIVITY AND SWELLS INCREASE SEAS W OF 95W S OF 10N.

$$
WALLY BARNES