000
AXPZ20 KNHC 192212
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC TUE JUN 19 2007

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 WAVES..

TROPICAL WAVE ALONG 87W N OF 4N MOVING W AT 10 KT. GENERALLY 
CLOUD FREE AREA NOTED N OF 9N ALONG THE WAVE...WITH ONLY 
ISOLATED LIGHT TO MODERATE CONVECTION S OF 9N WITHIN 120 NM OF 
THE WAVE AXIS.

TROPICAL WAVE ALONG 99W N OF 3N MOVING W AT 10-15 KT. CONVECTION 
ALONG THE WAVE FROM EARLIER THIS MORNING HAS 
DIMINISHED...LEAVING AN AREA OF MID LEVEL CLOUDINESS FROM 6N TO 
10N BETWEEN 98W TO 101W.  

TROPICAL WAVE ALONG 115W FROM 3N TO 16N MOVING W AT 10-15 KT. 
LARGE AREA OF MODERATE CONVECTION DIMINISHING TO THE W OF THE 
WAVE...FROM 7N TO 10N BETWEEN 118W TO 123W. THE WAVE APPEARS TO 
BE IN THE PROCESS OF MERGING WITH A WEAK CIRCULATION FORMING 
ALONG THE ITCZ...ROUGHLY NEAR 8N118W.

TROPICAL WAVE ALONG 130W FROM 2N TO 15N MOVING W AT 10 KT. NO 
CONVECTION IS ASSOCIATED WITH THIS WAVE. 

..ITCZ...

ITCZ AXIS IS CENTERED ALONG...9N84W 12N106W 9N121W 8N140W. 
SCATTERED MODERATE WITHIN 120 NM OF AXIS BETWEEN 118W AND 124W. 
SCATTERED MODERATE WITHIN 60 NM OF W OF 137W.

...DISCUSSION...

AN UPPER TROUGH EXTENDS FROM ROUGHLY 33N133W TO 22N143W MOVING 
THROUGH THE NW CORNER OF THE DISCUSSION AREA. FURTHER E...AN 
UPPER RIDGE IS ANALYZED ROUGHLY ALONG 120W. VERY LIMITED 
TROPICAL MOISTURE IS NOTED BETWEEN THESE FEATURES...AND 
MID/UPPER LEVELS REMAIN GENERALLY DRY N OF 17N. MEANWHILE...WEAK 
UPPER TROUGH IS NOTED E OF THE RIDGE OVER NW MEXICO. AT THE 
SURFACE...VISIBLE IMAGERY REVEALS LARGE FIELD OF STRATOCUMULUS 
CLOUDS CONTINUING TO ADVECT SWD N OF 12N AND W OF 188W. SHIP 
OBSERVATIONS AND QUIKSCAT IMAGERY SHOW MODERATE TO FRESH S TO SE 
SURFACE ON THE PERIPHERY OF 1021 MB SURFACE PRES NW OF THE AREA. 
THE MID/UPPER PATTERN BECOMES MORE AMPLIFIED OVER THE NEXT 24 TO 
48 HOURS AS THE UPPER RIDGE BUILDS AHEAD OF THE UPPER TROUGH 
DIGGING INTO THE AREA FROM THE NW. NLY FLOW ON THE ERN SIDE OF 
THE UPPER RIDGE WILL ALLOW THE UPPER TROUGH OVER NW MEXICO TO 
DEEPEN...ENHANCING SURFACE TROUGHINESS OVER MEXICO. AS THIS 
HAPPENS...SURFACE HIGH PRES WILL BUILD OVER THE ERN PACIFIC 
BEHIND THE UPPER TROUGH. THE RESULT WILL BE AN INCREASED 
GRADIENT BETWEEN THE STRONGER HIGH PRES AND THE TROUGH OVER 
MEXICO...ALLOWING FRESH NWLY WINDS OFF THE NRN BAJA COAST BY WED.

FURTHER S...MID/UPPER ELY SHEAR PREVAILS OVER ITCZ AS FAR W AS 
130W...S OF UPPER RIDGING. DIVERGENT FLOW ON THE WRN PERIPHERY 
OF THE UPPER RIDGING IS ENHANCING CONVECTION ALONG THE ITCZ 
BETWEEN 115W AND 120W. CONVECTION IS CURRENTLY AT A DIURNAL 
MINIMUM AND IS DIMINISHING ACCORDINGLY. HOWEVER...MAY SEE 
CONVECTION REFLARE OVERNIGHT IN THIS AREA. 

FURTHER E...FRESH TO STRONG ELY FLOW OVER THE CARIBBEAN WILL 
INCREASE BOUNDARY LAYER ELY FLOW OVER GULF OF PAPAGAYO. THIS 
WILL ALLOW WINDS TO REACH UP TO 20 KT PERIODICALLY IN THAT AREA. 
FAIRLY DRY SUBSIDENT AIR OVER THE CENTRAL AMERICAN COAST FROM 
COSTA RICA TO SOUTHERN MEXICO WILL KEEP CONVECTION MINIMAL AT 
LEAST THROUGH WED.

S OF 10N...QUIKSCAT SHOWS LIGHT TO MODERATE CROSS EQUATORIAL 
FLOW IN PLACE. HOWEVER...MAY THE SLY WINDS INCREASE TO UP TO 20 
KT E OF 110W BY LATE THU ACCOMPANIED BY INCREASED SWELL.

$$
CHRISTENSEN