000
AXPZ20 KNHC 292120
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC MON JUN 29 2009

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

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2100 UTC.

...TROPICAL WAVE...
TROPICAL WAVE IS ALONG 87W N OF 07N MOVING W 10-15 KT. A WEAK 
AREA OF LOW PRES HAS FORMED ALONG THE WAVE NEAR 10N...NEAR THE 
INTERSECTION OF THE ITCZ. CONVECTION IS MAINLY ORGANIZED TO THE 
W OF THE WAVE AXIS SHEARED BY UPPER LEVEL ELY WINDS.   

...ITCZ...

ITCZ IS CENTERED ALONG 10N85W 11N105W 08N115W 13N134W 09N140W. 
SCATTERED MODERATE TO STRONG CONVECTION IS FROM 03N TO 06N 
BETWEEN 79W AND 84W. SCATTERED MODERATE CONVECTION IS FROM 05N 
TO 09N BETWEEN 88W AND 102W. NUMEROUS MODERATE SCATTERED STRONG 
CONVECTION IS WITHIN 120 NM N AND 240 NM S OF THE AXIS BETWEEN 
103W AND 112W. 

...DISCUSSION...

SUBTROPICS...
LIGHT SFC WINDS EXIST ACROSS THE SUBTROPICS DUE TO A WEAK HIGH 
SITUATED NEAR 24N126W. LATEST QUIKSCAT AND ASCAT PASSES 
CONFIRM THAT NW WINDS HAVE DIMINISHED BELOW 20 KT NEAR THE BAJA 
COAST. WINDS MAY OCCASIONALLY PULSE TO NEAR 20 KT IN THAT 
REGION OVER THE NEXT COUPLE OF DAYS FORCED BY LOCAL TERRAIN 
VARIATIONS OVER THE PENINSULA AND A MODERATE PRESSURE GRADIENT 
BETWEEN THE HIGH AND LOW PRES TROUGHING N OF THE AREA. DESPITE 
THE OVERALL LIGHT FLOW...SEAS ARE ELEVATED TO 6-9 FT DUE 
PRIMARILY TO N SWELL PROPAGATING S FROM GALE FORCE WINDS OFF THE 
N CALIFORNIA COAST. THESE SWELLS ARE EXPECTED TO DIMINISH TO 
LESS THAN 8 FT BY WED. 

ALOFT...TROUGHING HAS BROADENED ACROSS THE AREA BASICALLY 
ENCOMPASSING THE ZONE W OF 120W WITH THE AXIS EXTENDING FROM 
30N137W TO A LOW NEAR 26N129W TO 20N124W. RIDGING HOLDS E OF 
120W ANCHORED BY A HIGH CENTER NEAR THE MEXICO/NEW MEXICO 
BORDER. ABUNDANT DRY AIR IS NOTED ACROSS MUCH OF THE AREA 
LIMITING THE DEVELOPMENT OF SIGNIFICANT CLOUDINESS. A FEW 
SHORTWAVE TROUGHS ARE EXPECTED TO MAINTAIN THE BROAD TROUGH W OF 
120W-125W OVER THE NEXT FEW DAYS WITH EACH SYSTEM LIKELY 
BRINGING A SLIGHT INCREASE IN MOISTURE.  

TROPICS...
THE TROPICS REMAIN QUIET ACROSS THE EAST PACIFIC AS THERE ARE NO 
WELL DEFINED AREAS OF SFC LOW PRESSURE. CONVECTION IS SPREAD OUT 
ACROSS THE ENTIRE BELT MAINLY NEAR THE ITCZ...AS OUTLINED ABOVE. 
THERE ARE A COUPLE OF OTHER WEATHER FEATURES PROVIDING 
ENHANCEMENT TO THE CONVECTION OR WINDS. ONE OF THESE IS THE 
TROPICAL WAVE DISCUSSED ABOVE. THE OTHER IS A SFC TROUGH ALONG 
16N134W 08N132W. THIS TROUGH HAS TIGHTENED THE PRESSURE GRADIENT 
PRODUCING NE 20 KT WINDS WITHIN 240 NM W OF THE AXIS...AS 
INDICATED BY AN EARLIER QUIKSCAT PASS. THIS FEATURE IS EXPECTED 
TO CONTINUE ITS W-NW DRIFT ALLOWING THE ENHANCED AREA OF WINDS 
TO SHIFT W WITHIN THE NEXT 12-24 HOURS. ASSOCIATED LOW-LEVEL 
CONVERGENCE IS ENHANCING NUMEROUS MODERATE SCATTERED STRONG 
CONVECTION WITHIN 300 NM W AND 180 NM E OF THE AXIS. 

CROSS-EQUATORIAL SLY WINDS ARE NEAR 20 KT NEAR THE 
AFOREMENTIONED SFC TROUGH S OF 06N W OF 125W WITH SEAS TO NEAR 8 
FT WITH SW SWELL. THESE WINDS AND SEA CONDITIONS ARE EXPECTED TO 
PERSIST OVER THE NEXT COUPLE OF DAYS AS THE PRESSURE GRADIENT 
REMAINS TIGHT BETWEEN THE SRN HEMISPHERE SUBTROPICAL RIDGE AND 
THE ITCZ. 

$$
CANGIALOSI