East Pacific Tropical Weather Discussion

000
AXPZ20 KNHC 051525
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC SUN JUL 05 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.

...SPECIAL FEATURES...
AN AREA OF LOW PRESSURE CENTERED ABOUT 300 NM SW OF MANZANILLO 
MEXICO HAS BECOME BETTER ORGANIZED THIS MORNING. SATELLITE 
IMAGES INDICATE A FAIRLY WELL DEFINED CENTER IN THE VICINITY OF 
17N109W MOVING WNW AT 10-15 KT. CONVECTION HAS INCREASED IN 
BANDS WITH THE MAIN CONVECTIVE AREA S OF THE CENTER FROM 13N-16N 
BETWEEN 108W AND 111W. NARROWER BANDS HAVE BEEN FILLING IN 
WITHIN 240 NM N OF THE CENTER. LATEST SCATTEROMETER DATA 
INDICATES 20-25 KT WINDS WITHIN 300 NM OVER THE NE QUADRANT...IN 
AGREEMENT WITH A SHIP OBSERVATION...BUILDING SEAS TO 11 FT. 
WINDS APPEAR TO BE LIGHTER OVER THE REMAINING QUADRANTS 
ESPECIALLY SW OF THE CENTER. THIS SYSTEM COULD BECOME A TROPICAL 
DEPRESSION OVER THE NEXT COUPLE OF DAYS AS IT CONTINUES ITS WNW 
MOTION. 

...TROPICAL WAVES...
TROPICAL WAVE HAS JUST ENTERED THE EXTREME EASTERN PACIFIC ALONG 
78W N OF 03N MOVING W NEAR 20 KT. THIS WAVE LIES WITHIN AN UPPER 
DIFFLUENT ZONE BETWEEN AN UPPER LOW OVER THE NW CARIBBEAN AND 
BROAD RIDGING. THIS UNSTABLE ENVIRONMENT IS SUPPORTING SCATTERED 
SHOWERS AND TSTMS OVER PORTIONS OF COSTA RICA...NICARAGUA AND 
THE SW CARIBBEAN. LOW-LEVEL SPEED CONVERGENCE ASSOCIATED WITH 
THE PAPAGAYO GAP WIND EVENT IS ALSO ENHANCING CONVECTION NEAR 
THE WAVE FROM 05N TO 09N E OF 89W.

TROPICAL WAVE IS ALONG 96W FROM 03N TO 15N MOVING W 15-20 KT. 
THIS POSITION IS BASED ON CONTINUITY AS THERE IS NOT ANY OBVIOUS 
EVIDENCE OF THE FEATURE IN THE AVAILABLE DATA. 

...ITCZ...
ITCZ AXIS IS CENTERED ALONG 08N82W 07N98W 13N105W 14N113W 
09N125W 07N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION 
IS FROM 05N TO 09N E OF 89W. SCATTERED MODERATE ISOLATED STRONG 
CONVECTION IS WITHIN 240 NM OF THE AXIS BETWEEN 95W AND 105W. 
SCATTERED MODERATE CONVECTION IS FROM 08N TO 10N BETWEEN 119W 
AND 121W.

...DISCUSSION...

S OF 20N...

THE SPECIAL FEATURE IS THE MAIN FORECAST CONCERN OVER THE NEXT 
COUPLE OF DAYS. GFS/UKMET GENERALLY WEAKEN THIS SYSTEM OR KEEP 
IT AT THE SAME INTENSITY OVER THE NEXT DAY OR TWO WHILE ECMWF 
AND CMC SHOW SOME SLIGHT STRENGTHENING. INCREASED WINDS AND SEAS 
IN LATEST HIGH SEAS FORECAST...GIVEN THE IMPROVED ORGANIZATION 
OF THE LOW...IN BETTER AGREEMENT WITH THE MORE AGGRESSIVE 
MODELS. 

A WEAK TROUGH ALONG 134W IS PRODUCING LITTLE SIGNIFICANT 
SHOWER/TSTM ACTIVITY BUT IS ENHANCING NE TRADES TO NEAR 20 KT W 
OF THE AXIS. NE 20 KT TRADES WILL BE CONFINED TO A SMALL REGION 
W OF 130-135W OVER THE NEXT COUPLE OF DAYS AS THE PRESSURE 
PATTERN HOLDS.

SW SWELL OF 15-17 SECONDS IS ELEVATING SEAS OVER 8 FT ACROSS 
MUCH OF THE AREA S OF 12N BETWEEN 90W AND 125W. THIS SWELL WILL 
CONTINUE TO AFFECT THIS GENERAL REGION OVER THE NEXT FEW DAYS.

GULF OF PAPAGAYO...NO HELP FROM SCATTEROMETER DATA SO FAR TODAY 
AS ASCAT MISSED THE AREA AND QUIKSCAT DATA IS AT THE EDGE OF 
SWATH...SO INFORMATION MAY NOT BE VERY RELIABLE. BASED ON A SHIP 
REPORT OF 15 KT NEAR 10N89W AND MODEL GUIDANCE ITS LIKELY THAT 
THE EVENT IS PAST PEAK. WINDS ARE FORECAST TO FALL BELOW 20 KT 
WITHIN THE NEXT 36 HOURS AS THE CARIBBEAN TRADES WEAKEN.

N OF 20N...
DEEP LAYER HIGH PRESSURE IS IN CONTROL OVER THE SUBTROPICAL 
REGION WITH THE MID-UPPER HIGH CENTERED NEAR 27N123W AND THE 
1020 MB SFC CENTER NEAR 29N129W. THIS PATTERN IS ALLOWING FOR 
LIGHT TO MODERATE SFC WINDS ACROSS THE ZONE...EXCEPT FOR 
OCCASIONALLY SURGES TO NEAR 20 KT NEAR THE N BAJA COAST 
ENHANCED BY THE LOCAL TERRAIN. ABUNDANT STABLE AIR IS PRODUCING 
FAIR WEATHER ACROSS THE AREA AND LITTLE CHANGE IS FORECAST OVER 
THE NEXT DAY OR SO.

$$
CANGIALOSI