000
AXPZ20 KNHC 040321
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC THU JUN 04 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 
0315 UTC.

...TROPICAL WAVE...
A TROPICAL WAVE EXTENDS ALONG 81W MOVING W AT 10 TO 15 KT. THE 
WAVE WILL BE MOVING INTO AN AREA OVER THE NEXT DAY WITH FAIRLY 
DRY SUBSIDENT NORTHERLY FLOW. NONETHELESS...THERE MAY BE A 
MODEST INCREASE IN THE EARLY MORNING DRAINAGE CONVECTION ALONG 
THE COLOMBIAN AND COSTA RICAN COASTLINES RELATED TO THE WAVE. 
UPPER PATTERN BECOMES A LITTLE MORE DIVERGENT BY FRI...AND MAY 
AID CONVECTIVE GROWTH ALONG THE WAVE AS IT PASSES 90W.

...ITCZ...
AXIS FROM 07N78W TO 07N85W TO 14N105W TO 07N130W TO 07N140W. 
SCATTERED MODERATE CONVECTION IS WITHIN 90 NM N OF AXIS BETWEEN 
90W AND 98W. SCATTERED MODERATE CONVECTION IS FROM 08N TO 12N 
BETWEEN 105W AND 106W. SCATTERED MODERATE AND ISOLATED STRONG 
CONVECTION IS FROM 12N TO 15N BETWEEN 110W AND 115W. SCATTERED 
MODERATE CONVECTION IS WITHIN 120 NM N OF AXIS BETWEEN 125W AND 
128W.

...DISCUSSION...
N OF 20N...AMPLIFIED PATTERN PERSISTS WITH MID/UPPER CYCLONIC 
CIRCULATION NEAR 36N126W IS DRIFTING SLOWLY EAST...AHEAD OF 
SHARP UPPER RIDGE ALONG 145W. ASSOCIATED 1014 MB SURFACE LOW IS 
CENTERED NEAR 33N125W. A SURFACE RIDGE EXTENDS FROM 28N140W TO S 
OF BAJA NEAR 20N110W. OVERLAYING SCATTEROMETER DATA AND A COUPLE 
OF SHIP OBSERVATIONS SHOW LIGHT TO MODERATE FLOW AROUND THE 
RIDGE...INDICATIVE OF A WEAK PRESSURE GRADIENT. THERE ARE A 
COUPLE OF AREAS WHERE WINDS COULD APPROACH 20 KT OVER THE NEXT 
COUPLE OF DAYS CONTINUE TO BE OFF THE CENTRAL BAJA COAST WHERE 
WIND FUNNEL BETWEEN THE HIGH PRES RIDGE AND THE INLAND TERRAIN. 
THE OTHER AREA IS OVER THE NORTHERN GULF OF CALIFORNIA WHERE 
ENHANCED SW FLOW AHEAD OF THE MID/UPPER CYCLONIC CIRCULATION IS 
ENHANCING WESTERLY MORNING DRAINAGE FLOW.

S OF 20N...A CUTOFF UPPER CYCLONIC CIRCULATION IS CENTERED NEAR 
16N132W. DIVERGENT FLOW ALOFT ON THE SE SIDE OF THE CIRCULATION 
IS ENHANCING SCATTERED CLUSTERS OF CONVECTION ALONG THE ITCZ. AN 
ASCAT PASS FROM AROUND 18Z PROVIDED A HINT OF SURFACE TROUGH 
ALONG 127W FROM 06N TO 10N. THIS IS UNDER THE MAXIMUM DIVERGENCE 
SE OF THE UPPER LOW...AND TIES IN WITH A SURFACE TROUGH EAST OF 
THIS AREA YESTERDAY. LOW LEVEL CONVERGENCE OF NE TRADES ON THE 
SOUTHERN PERIPHERY OF THE SURFACE RIDGE TO THE NORTH AND THIS 
TROUGH...IS ALSO AIDING THE CONVECTIVE GROWTH. THIS FLOW IS 
GENERALLY NO MORE THE 15 KT DUE TO A FAIRLY WEAK PRESSURE 
GRADIENT...THUS THE CONVECTION IS MOSTLY MODERATE. A SECOND 
SURFACE TROUGH IS NEAR 115W...UNDER DECENT DIVERGENCE ALOFT ON 
THE SW SIDE OF AN UPPER ANTICYCLONE. AGAIN...CONVECTION IS 
FAIRLY MODEST GIVEN WEAK LOW LEVEL CONVERGENCE. FURTHER 
WEST...SCATTEROMETER CONFIRMS PERSISTENT 20 KT FLOW THROUGH GULF 
OF PAPAGAYO.

$$
CHRISTENSEN