000
AXPZ20 KNHC 262200
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC WED AUG 26 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 
2145 UTC.

...SPECIAL FEATURE...

TROPICAL STORM IGNACIO WAS CENTERED NEAR 22.1N 124.5W OR ABOUT 
815 NM W OF THE SOUTHERN TIP OF BAJA CALIFORNIA AT 26/2100 
UTC...MOVING NW OR 310 DEGREES AT 10 KT. MAXIMUM SUSTAINED WINDS 
REMAIN 40 KT WITH GUSTS TO 50 KT AND THE ESTIMATED MINIMUM 
PRESSURE WAS 1002 MB. VISIBLE SATELLITE IMAGERY INDICATES 
IGNACIO IS RAPIDLY WEAKENING WITH THE LOW LEVEL CENTER BECOMING 
NEARLY DECOUPLED FROM THE MID AND UPPER LEVEL CIRCULATION AND 
ASSOCIATED AREA OF DEEP CONVECTION. THE WEAKENING
CONVECTION IS ORGANIZED IN A LARGE CURVED BAND WELL N AND E OF 
THE CENTER WITH SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS 
WITHIN THE BAND DISPLACED 180-240 NM FROM THE LOW LEVEL CENTER. 
IGNACIO IS EXPECTED TO WEAKEN TO A REMNANT LOW WITHIN 24 HOURS
AS THE CENTER MOVES OVER INCREASINGLY COOLER WATERS. ADDITIONAL 
INFORMATION CAN BE FOUND UNDER AWIPS/WMO HEADERS 
MIATCMEP3/WTPZ23 KNHC.
  
...TROPICAL WAVES...
A TROPICAL WAVE IS ALONG 92W N OF 06N MOVING W NEAR 15 KT OVER 
THE PAST 24 HOURS. VISIBLE SATELLITE IMAGERY INDICATED A SMALL 
BUT WELL DEFINED LOW TO MID-LEVEL CIRCULATION ALONG THE WAVE 
AXIS NEAR 12.5N...JUST SOUTH OF GUATEMALA. CONVECTION IS
WRAPPING AROUND THIS SWIRL DESPITE THE PRESENCE OF STRONG UPPER 
LEVEL EASTERLY WINDS. ADDITIONAL AREAS OF CONVECTION WERE NOTED 
OVER GUATEMALA...BELIZE AND THE YUCATAN PENINSULA...NEAR THE 
NORTHERN END OF THE WAVE. FURTHER DEVELOPMENT...IF ANY...IS 
EXPECTED TO BE SLOW TO OCCUR.  

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE IS ALONG 08N84W TO 08N105W TO 
06N112W TO 14N126W TO 12N140W. SCATTERED MODERATE ISOLATED 
STRONG FROM 04N TO 14N BETWEEN 104W AND 118W AND FROM 08N TO 13N 
W OF 130W..AND WITHIN 45 NM 14N133W.

...DISCUSSION...

A SURFACE TROUGH EXTENDS FROM 13N108W TO 04N112W. SATELLITE 
IMAGES INDICATED INCREASING CYCLONIC TURNING IN THE CLOUD FIELD 
ALONG A SW TO NE AXIS. SCATTERED MODERATE TO STRONG CONVECTION 
WAS NOTED WITHIN 90-120 NM EITHER SIDE OF THE TROUGH AXIS...AND
ALSO ORGANIZED IN BANDS TO THE NW OF THE TROUGH AND WELL TO THE 
SOUTH OF THE TROUGH. MANY OF THE NUMERICAL MODELS SHOW SOME 
DEVELOPMENT OF THIS SYSTEM OVER THE NEXT FEW DAYS AS IT TRACKS 
WEST-NORTHWESTWARD.

AT THE MID AND UPPER LEVELS...A LARGE ANTICYLONE...DISPLACED 
TO THE E OF IGNACIO DOMINATES THE FLOW OVER THE DISCUSSION AREA 
E OF ABOUT 120W. A NARROW SHARP UPPER LEVEL TROUGH EXTENDED 
THROUGH 32N135W TO 20N142W. A VAST AREA OF MID TO UPPER LEVEL 
DRY AIR ALOFT IN THE AREA BETWEEN THE TROUGH AND ANTICYCLONE 
RESULTED IN BENIGN WEATHER CONDITIONS ACROSS THE AREA. 

A LARGE UPPER TROUGH CURRENTLY NW OF THE AREA N OF 35N ALONG 
145W IS EXPECTED TO DIG SOUTHEASTWARD OVER THE NEXT 12-24 HOURS 
DRAGGING A COLD FRONT TO THE NW CORNER LATE TONIGHT. WHILE WINDS 
SHOULD BE FAIRLY LIGHT ALONG THE FRONT AT THAT TIME...NW SWELL 
COMBINED WITH THE EFFECTS OF WEAKENING IGNACIO WILL CAUSE 8-12 
FT CONFUSED SEAS OVER THE NW PORTION OF THE SUBTROPICS.

GULF OF TEHUANTEPEC...A HIGH RESOLUTION 1230 UTC QUIKSCAT PASS 
REVEALED 20-30 KT N WINDS OVER THE GULF OF TEHUANTEPEC. THIS 
STRONG FLOW IS EXPECTED TO CONTINUE FOR ANOTHER DAY OR 
SO...ESPECIALLY DURING THE OVERNIGHT AND MORNING HOURS WHEN 
DRAINAGE FLOW IS MAXIMIZED. HOWEVER...WINDS ARE FORECAST TO 
DIMINISH BY 48 HOURS AS THE TROPICAL WAVE MOVES W OF THE 
AREA...WHICH SHOULD LIMIT FUNNELING.

$$
COBB