000
AXPZ20 KNHC 212154
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC MON AUG 21 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...
TS HECTOR NEAR 22.3N 135.5W 1002 MB AT 2100 UTC AUG 21 MOVING NW 
OR 325 DEG AT 6 KT. MAXIMUM SUSTAINED WINDS 40 KT GUSTS 50 KT. 
WLY SHEAR CONTINUES WITH SCATTERED MODERATE CONVECTION OVER N 
QUAD WITHIN 90 NM OF 25N134W. HECTOR WILL LIKELY WEAKEN TO A TD 
TONIGHT. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO 
HEADERS MIATCMEP4/WTPZ24 KNHC FOR MORE DETAILS. 

TS ILEANA NEAR 12.8N 103.2W 1004 MB AT 2100 UTC AUG 21 MOVING 
WNW OR 300 DEG AT 10 KT. MAXIMUM SUSTAINED WINDS 35 KT GUSTS 45 
KT. SCATTERED MODERATE TO STRONG CONVECTION IS NOTED WITHIN 180 
NM NE QUAD AND WITHIN 240 NM W SEMICIRCLE OF CENTER WITH 
CONVECTION ORGANIZING WITHIN BANDS. A SMALL ANTICYCLONE NEAR 
22N105W HAS A WEAK RIDGE SE OVER ILEANA PROVIDING PLENTY OF 
UPPER VENTILATION...WITH LATEST WATER VAPOR IMAGERY INDICATING 
THAT ILEANA MAY ALREADY HAS ITS OWN ANTICYCLONE ALOFT. MODELS 
SUGGEST THAT THIS SMALL ANTICYCLONE WILL DRIFT N AND MERGED WITH 
A LARGE ANTICYCLONE OVER NE TEXAS WITH A RIDGE EXTENDING W ALONG 
29N CRESTING OVER THE NRN BAJA PENINSULA. THIS SHOULD STEER 
ILEANA W AND ALLOW THE CYCLONE TO INTENSIFY AS IT TRACKS OVER 
WARM SEAS SURFACE WATERS.

...TROPICAL WAVES...
A TROPICAL WAVE N OF 4N ALONG 87W HAS MOVED W AT 15 KT THE PAST 
24 HOURS. CONVECTION IS ISOLATED AT BEST ALONG THE WAVE AXIS IN 
THE E PAC...BUT CLUSTERS OF STRONG CONVECTION ARE FLARING OVER 
LAND NEAR 17N90W AND 14N84W. 

A TROPICAL WAVE ALONG 128W FROM 3N TO 15N HAS MOVED W 12 KT THE 
PAST 24 HOURS. BROAD CYCLONIC TURNING IS NOTED ALONG THE ITCZ 
WITH SCATTERED MODERATE CONVECTION ENHANCED FROM 6N TO 
13N.

...ITCZ...
THE ITCZ AXIS IS CENTERED ALONG 7N78W 10N94W 13N103W 8N121W 
12N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED 
WITHIN 120 NM OF 5N82W AND WITHIN 30 NM OF 7N92W AND WITHIN 150 
NM EITHER SIDE OF LINE 9N108W 7N126W 13N132W. 

...DISCUSSION...
A NEGATIVE TILT SHORTWAVE TROUGH LIES ALONG 32N132W 27N116W THEN 
CONTINUES S ALONG 21N118W THROUGH AN UPPER CYCLONE AT 13N119W 
AND CONTINUING S TO A BASE AT 9N118W. VERY DRY AIR IS NOTED 
ALONG THE TROUGH AXIS FROM 27N TO 32N.

AN ANTICYCLONE IS CENTER NEAR 19N125W AND RIDGES N TO A GENTLE 
CREST ALONG POINTS 25N136W 31N128W 28N119W AND IS AMPLIFYING N 
ATTM. 

ANOTHER ANTICYCLONE IS QUASI STATIONARY AREA NEAR 18N147W 
RIDGING E ALONG 14N TO A CREST AT 14N132W. 
     
A SMALL UPPER CYCLONE IS ESTIMATED NEAR 22N97W WITH AN UPPER 
TROUGH EXTENDING S TO 18N96W. AN UPPER ANTICYCLONE HAS FORMED 
NEAR 16N92W WITH ITS ENVELOPE OF ANTICYCLONIC FLOW EXTENDING S 
ACROSS THE E PAC WATERS N OF 17N BETWEEN 93W AND 100W.  

AT THE SURFACE...A RIDGE EXTENDS SE ALONG 32N132W TO 16N112W 
WITH NW WINDS SURGING TO 20 KT AND SEAS TO 8 FT CONTINUING OVER 
THE PAC WATERS N OF 25N ALONG THE W COAST OF THE BAJA PENINSULA. 
MODELS SUGGEST THE GRADIENT WILL RELAX TONIGHT. 

$$
NELSON