000
AXPZ20 KNHC 131548
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC WED MAY 13 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 
1500 UTC.

...ITCZ...
AXIS 07N78W TO 11N106W TO 
06N128W TO 06N140W. SCATTERED MODERATE ISOLATED STRONG WITHIN 
180 NM S OF AXIS E OF 80W. SCATTERED MODERATE WITHIN 60 NM OF 
AXIS BETWEEN 85W AND 88W. SCATTERED MODERATE WITHIN 120 NM OF 
AXIS BETWEEN 95W AND 105W.

...DISCUSSION...
N OF 20N...STRONG ZONAL UPPER JET ENERGY NORTH OF THE AREA IS 
CUTTING OFF AN UPPER LOW NEAR 25N135W.  THE UPPER PATTERN 
BECOMES MORE AMPLIFIED THURSDAY AS THE CUTOFF LOW WEAKENS AND 
SHIFTS WEST TOWARD HAWAII...AS MID/UPPER RIDGING BUILDS ALONG 
135W...AND A TROUGH DIGS OVER SOUTHERN CALIFORNIA/NORTHERN BAJA. 
THE MAIN IMPACT AT THE SURFACE WILL BE THAT A 1025 MB SURFACE 
HIGH PRES CENTER NEAR 33N131W WILL REMAIN STATIONARY AND 
STRENGTHEN SLIGHTLY. THIS IN TURN WILL MAINTAIN NORTHERLY STRONG 
WINDS DOWN THE SOUTHERN CALIFORNIA COAST INTO NORTHERN BAJA. 
SCATTEROMETER DATA IS SHOWING A SWATH OF THESE WINDS CURVING 
MORE TO THE SW AROUND THE SOUTHERN PERIPHERY OF THE HIGH PRES. 
GALE FORCE WINDS ARE EXPECTED OFF SOUTHERN CALIFORNIA...AND THE 
STRONG PERSISTENT NORTHERLY FLOW WILL PROMOTE NORTHERLY SWELL 
OFF NORTHERN BAJA AS A RESULT. 

S OF 20N...THE MAIN UPPER FEATURE REMAINS A STATIONARY 14N100W S 
OF ACAPULCO MEXICO. THIS IS EAST OF AN UPPER TROUGH EXTENDING 
OVER NICARAGUA TO SE OF THE UPPER RIDGE NEAR 02N100W. DIVERGENCE 
ALOFT BETWEEN THESE FEATURES CONTINUES TO SUPPORT SCATTERED 
CONVECTION ALONG THE ITCZ BETWEEN 85W AND 105W. FURTHER 
EAST...EARLY MORNING SCATTERED MODERATE WITH ISOLATED STRONG 
CONVECTION IS STARTING TO DIE DOWN. MORNING DRAINAGE FLOW ALONG 
WITH FRESH CARIBBEAN TRADES CONTINUE TO FILTER INTO THE GULF OF 
PAPAGAYO...ALTHOUGH THIS FLOW MAY BE FINALLY TAPERING OFF.

$$
CHRISTENSEN