000
AXPZ20 KNHC 300316
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC SAT MAY 30 2009

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

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0330 UTC.

...TROPICAL WAVES...
TROPICAL WAVE IS ALONG 95W FROM 02N-12N MOVING W 10 TO 15 KT. 
SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS NOTED EITHER 
SIDE OF THE WAVE AXIS PARTICULARLY TO NEAR THE INTERSECTION WITH 
THE ITCZ. THIS WAVE SHOWS UP WELL AS A HIGH AMPLITUDE MOISTURE 
SURGE ON THE UW-CIMSS TPW PRODUCT. BROAD CYCLONIC TURNING IS 
NOTED ON SATELLITE IMAGERY. THE GFS COMPUTER MODEL SUGGESTS THE 
DEVELOPMENT OF A LOW PRES IN THE VICINITY OF THE WAVE WITHIN 
ABOUT 48 HOURS.

...ITCZ...
THE ITCZ AXIS IS ALONG 06N78W TO 08N94W TO 08N105 TO 12N120W TO 
08N130W TO 05N140W. SCATTERED MODERATE TO ISOLATED STRONG 
CONVECTION IS FROM 06N TO 12N BETWEEN 92W AND 100W.  

...DISCUSSION...
A WEAK 1019 MB SURFACE HIGH CENTERED NEAR 25N128W COVERS THE 
NORTHERN WATERS N OF 18N AND W OF 115W PRODUCING MOSTLY FAIR 
WEATHER AND LIGHT WINDS. THE COMBINATION OF THIS HIGH WITH A 
WEAK SURFACE LOW PRES TROUGH ALONG CENTRAL MEXICO IS RESULTING 
IN FRESH NW WINDS N OF 23N WITHIN 90 NM OF BAJA CALIFORNIA 
COAST. LITTLE CHANGE IS EXPECTED IN THE WEATHER PATTERN DURING 
THE NEXT 24 HOURS AS THE HIGH PRES CENTER MOVES TO THE NW TO A 
POSITION NEAR 27N129W. A COLD FRONT IS MOVING ACROSS THE NW 
CORNER OF THE DISCUSSION AREA. LONG PERIOD SWELLS FROM THE NW 
WILL FOLLOW THE FRONT...RAISING SEAS TO 12 FT EARLY SAT. A 
WEAK SURFACE TROUGH IS ANALYZED FROM 14N122W TO 07N128W. A FEW 
SHOWERS ARE EITHER SIDE OF TROUGH AXIS...MAINLY NEAR THE SOUTH 
END OF THE TROUGH AXIS. AN EARLIER ASCAT PASS SHOWED THE WIND 
SHIFT ASSOCIATED WITH THIS TROUGH. 

ALOFT...AN UPPER-LEVEL LOW OVER IS OVER SOUTHERN CALIFORNIA WITH 
AN UPPER-LEVEL TROUGH EXTENDING OVER THE N WATERS TO NEAR 
22N120W. A JET-STREAM BRANCH WITH CORE WINDS OF 70-80 KT ENTERS 
THE FORECAST REGION NEAR 21N140W. AN UPPER-LEVEL HIGH CENTERED 
NEAR 12N94 HAS AN ELONGATED RIDGE EXTENDING NWD ACROSS THE 
YUCATAN PENINSULA AND THE GULF OF MEXICO. THE RIDGE ALSO 
DOMINATES CENTRAL AMERICA AND WESTERN COLOMBIA. THIS UPPER-LEVEL 
FEATURE IS SUPPORTING THE CONVECTION MENTIONED IN THE ITCZ 
SECTION.  

$$
GR