000
AXPZ20 KNHC 090937
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC TUE JUN 09 2009

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

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0930 UTC.

...ITCZ...
ITCZ AXIS IS CENTERED ALONG 07N77W TO 08N95W TO 12N114W TO 
07N132W TO 08N140W. SCATTERED MODERATE ISOLATED STRONG 
CONVECTION WITHIN FROM 09N TO 12N BETWEEN 116W AND 119W. 
SCATTERED MODERATE CONVECTION FROM 07N TO 09N BETWEEN 96W AND 
101W. 
    
...DISCUSSION...

W OF 110W...
MID TO UPPER LEVEL TROUGH EXTENDS SW FROM A COMPLEX CYCLONIC 
CIRCULATION SW OF THE CALIFORNIA AND BAJA CALIFORNIA COASTS
WITH A MEAN CENTER NEAR 31N123W...THROUGH 22N130W AND WEAKENS 
INTO A SHEAR AXIS THROUGH 19N140W TO JUST S OF THE HAWAIIAN 
ISLANDS. MODERATE TO STRONG SUBSIDENCE/DRYING ALOFT WAS NOTED 
WITHIN AND N OF THE TROUGH AXIS. AXIS OF SUBTROPICAL JETSTREAM 
WAS SWEEPING THROUGH THE BASE OF AFOREMENTIONED TROUGH/SHEAR
AXIS...THEN TURNED NNE ACROSS BAJA CALIFORNIA INTO THE SW CONUS. 
SATELLITE DERIVED WINDS WERE IN THE 100-120 KT RANGE NEAR THE 
CORE OF THE JET WHICH WERE ADVECTING COPIOUS AMOUNTS OF TROPICAL 
MOISTURE NWD FROM FROM THE VICINITY OF A PAIR OF 1009 MB SFC 
LOWS NEAR 09N123W...AND 11N117W. THE SECOND LOW IS FORECAST TO 
BECOME THE MORE DOMINANT LOW AND HAS A MODERATE PROBABILITY OF 
DEVELOPING INTO A TROPICAL CYCLONE IN THE NEXT 48 HOURS. HOWEVER
THE WINDOW OF OPPORTUNITY IS GRADUALLY CLOSING AS THE STRONG SW 
WINDS AHEAD OF THE TROUGH ARE APPROACHING THE AREA OF LOW 
PRESSURE. ELSEWHERE AT THE SURFACE...1023 MB HIGH IS CENTERED 
NEAR 35N146W WITH A SURFACE RIDGE EXTENDING SE TO 20N110W.  
PERSISTENT SURFACE PRESSURE GRADIENT BETWEEN THE HIGH AND LOWER 
PRESSURES OVER ARIZONA IS PRODUCING 20 KT NW WINDS ALONG THE W 
COAST OF THE BAJA. THESE WINDS ARE FORECAST TO CONTINUE OVER THE 
NEXT SEVERAL DAYS. 

E OF 110W...
A LARGE BUT ELONGATED UPPER LEVEL ANTICYCLONE CENTERED SW OF 
MEXICO NEAR 17N108W IS PRODUCING NORTHERLY MID/UPPER LEVEL FLOW 
ACROSS MEXICO AND THE ISTHMUS OF TEHUANTEPEC. THE DIFFLUENT 
NATURE OF THE FLOW WAS ALLOWING SOME CONVECTION TO FORM WITHIN 
THE ISTHMUS AND ALSO MAINTAIN SOME DEEP CONVECTION ALONG THE
ITCZ BETWEEN 96W AND 101W. A DEFORMATION/SHEAR AXIS CUTS ACROSS
EL SALVADOR/NICARAGUA. DIFFLUENT SW FLOW ALOFT E OF THE AXIS WAS 
PRODUCING SCATTERED THUNDERSTORMS OVER CENTRAL AMERICA FROM 
PANAMA TO GUATEMALA. CONVECTION WILL CONTINUE TO FLARE OVER THIS 
AREA DURING THE NEXT COUPLE OF DAYS.   

MARINE ISSUES...
LONG PERIOD SWELL OF 16-18 SECONDS EMANATING FROM A STRONG 
CYCLONE OVER THE SOUTHERN HEMISPHERE HAS CROSSED THE EQUATOR AND 
IS SLATED TO ARRIVE ALONG THE COAST OF CENTRAL AMERICA ON WED.
A SECOND SURGE OF LONGER PERIOD SWELL...18-19 SECONDS SHOULD 
ARRIVE LATE THU AND FRI...CARRYING THE POTENTIAL FOR LARGE AND 
DANGEROUS BREAKING SURF CONDITIONS ALONG THE COAST FROM BAJA 
CALIFORNIA TO PANAMA. 
 
$$
COBB