000
AXPZ20 KNHC 261600
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC WED AUG 26 2009

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

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1545 UTC.

...SPECIAL FEATURE...

TROPICAL STORM IGNACIO WAS CENTERED NEAR 21.6N 124.0W OR ABOUT 
785 NM W OF THE SOUTHERN TIP OF BAJA CALIFORNIA AT 26/1500 
UTC...MOVING NW OR 305 DEGREES AT 12 KT. MAXIMUM SUSTAINED WINDS 
HAVE DECREASED TO 40 KT WITH GUSTS TO 50 KT AND THE ESTIMATED 
MINIMUM PRESSURE WAS 1002 MB. VISIBLE SATELLITE IMAGERY 
INDICATES IGNACIO IS MUCH LESS ORGANIZED WITH THE LOW LEVEL 
CENTER BECOMING DECOUPLED FROM THE AREA OF DEEP CONVECTION. 
THE CONVECTION IS ORGANIZED IN A LARGE CURVED BAND WELL N AND E 
OF THE CENTER WITH SCATTERED MODERATE ISOLATED STRONG CONVECTION 
DISPLACED 120 NM FROM THE LOW LEVEL CENTER IN A 150-180 NM WIDE 
BAND. WEAKENING IS FORECAST AS IGNACIO MOVES OVER INCREASINGLY 
COOLER WATERS AND IT SHOULD BECOME A REMNANT LOW IN A COUPLE OF 
DAYS. ADDITIONAL INFORMATION CAN BE FOUND UNDER AWIPS/WMO 
HEADERS MIATCMEP3/WTPZ23 KNHC.
  
...TROPICAL WAVES...
A TROPICAL WAVE IS ALONG 90W N OF 06N MOVING W NEAR 15 KT OVER 
THE PAST 24 HOURS. LOW TO MID-LEVEL CLOUD MOTIONS IN VISIBLE 
SATELLITE IMAGERY SUGGEST A SMALL CIRCULATION ALONG THE AXIS 
JUST SOUTH OF GUATEMALA. CONVECTION IS BEGINNING TO WRAP AROUND 
THIS SWIRL AS STRONG UPPER LEVEL EASTERLY WINDS BEGIN TO ABATE. 
MUCH OF THE CONVECTION OVER CENTRAL AMERICA HAS DISSIPATED 
EXCEPT FOR A SMALL AREA OF SOUTHERN BELIZE AND EASTERN 
GUATEMALA. FURTHER DEVELOPMENT...IF ANY...IS EXPECTED TO BE SLOW 
TO OCCUR.  

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE IS ALONG 08N84W TO 08N97W TO 
09N105W TO 06N113W TO 09N140W. SCATTERED MODERATE WITHIN 120 NM 
S OF ITCZ AXIS BETWEEN 105W AND 115W. 

...DISCUSSION...

A BROAD TROUGH OF LOW PRESSURE IS LOCATED ALONG 107W FROM 03N TO 
12N. SATELLITE IMAGES SHOW A BROAD ENVELOPE OF LOW TO MID-LEVEL 
CYCLONIC TURNING WITH CONVECTION ORGANIZED IN A BROKEN BAND WELL 
TO THE SOUTH OF THE TROUGH AXIS. MANY OF THE DYNAMICAL MODELS 
SHOW SOME DEVELOPMENT OF THIS SYSTEM OVER THE NEXT FEW DAYS AS 
IT TRACKS WEST-NORTHWESTWARD.

SURFACE TROUGH WHICH WAS LOCATED FARTHER W ALONG 132W HAS 
DISSIPATED WITHIN THE ITCZ. QUIKSCAT DATA SHOWS A BROAD SWATH OF 
SW 20 KT WINDS E OF THE AXIS FEEDING INTO TROPICAL STORM 
IGNACIO. CONVECTION IS ISOLATED ALONG THE ITCZ BETWEEN 
132W-137W.  

THE REMAINDER OF THE REGION IS RELATIVELY QUIET...ESPECIALLY 
OVER THE SUBTROPICS WHERE ABUNDANT DRY AIR ALOFT IS SUPPORTING 
FAIR WEATHER.

A LARGE UPPER TROUGH OVER THE NORTH PACIFIC IS EXPECTED TO DIG 
SOUTHEASTWARD OVER THE NEXT 12-24 HOURS DRAGGING A COLD FRONT TO 
THE NW CORNER TOMORROW NIGHT. 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 A LARGE PORTION OF THE SUBTROPICS W OF 125W.

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