000
AXPZ20 KNHC 170315
TWDEP 

TROPICAL WEATHER DISCUSSION     
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC FRI AUG 17 2007

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 
0300 UTC.

...TROPICAL WAVES...

TROPICAL WAVE ALONG 104W N OF 5N IS MOVING W AT 10 TO 15 KT 
TOWARD A LOW PRES 1007 MB CENTERED NEAR 16N107W. BOTH THE LOW 
AND WAVE ARE EMBEDDED IN A BROAD TYPE MONSOON FLOW PATTERN THAT 
COVERS THE AREA FROM 7N17N E OF 115W. IN ADDITION...DIVERGENT 
FLOW ALOFT AT THE SOUTHERN EDGE OF AN UPPER ANTICYCLONE OVER 
CENTRAL MEXICO IS ENHANCING CONVECTION ALONG THE WAVE AND WHERE 
THE WAVE AND THE ITCZ OVERLAP NEAR THE MEXICAN COAST. SCATTERED 
MODERATE TO ISOLATED STRONG CONVECTION IS EVIDENT AT THE NRN END 
OF THE WAVE FROM 18N TO 22N...BETWEEN THE MEXICAN COAST AND 108W.

TROPICAL WAVE ALONG 125W FROM 5N TO 16N IS MOVING W AT 10 KT. 
SUBSIDENT FLOW ALOFT IS MAINTAINING DEEP LAYER DRY AIR OVER THE 
AREA. THEREFORE NO SIGNIFICANT CONVECTION IS ASSOCIATED WITH THE 
WAVE.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 6N77W 8N88W 17N100W 12N115W 12N136W 
11N140W. SCATTERED MODERATE WITHIN 60 NM OF AXIS E OF 84W. 
SCATTERED MODERATE WITHIN 60 NM S OF AXIS BETWEEN 112W AND 118W. 

...DISCUSSION...

E OF 120W...DIVERGENCE ALOFT OF A BROAD UPPER LEVEL ANTICYCLONE 
OVER N CENTRAL MEXICO IS ENHANCING THE AFOREMENTIONED CONVECTION 
S OF THE MEXICAN COAST FROM 13N TO 17N BETWEEN 102W AND 111W. 
THE LOW PRES 1009 MB IS EXPECTED TO REMAIN QUASI-STATIONARY OVER 
THE NEXT 24 HOURS AS THE WAVE TO THE E MOVES CLOSER. THE LOW 
WILL THEN BEGIN TO SHIFT SLOWLY TO THE NW IN CONJUNCTION WITH 
THE UPPER SUPPORT STARTING LATE FRI INTO SAT. THIS CLUSTER OF 
THUNDERSTORMS WILL REMAIN FAIRLY DISORGANIZED AS IT MOVES TO THE 
NW...REACHING AN AREA APPROXIMATELY 300 NM SW OF THE SOUTHERN 
TIP OF BAJA BY LATE SUN...WHERE IT WILL ENCOUNTER DRIER AIR AND 
SLIGHTLY COOLER WATER. FURTHER E...ANOTHER TROPICAL WAVE WILL 
EMERGE OUT OF THE CARIBBEAN INTO THE FAR EASTERN 
PACIFIC...BRINGING SLIGHTLY MORE CONVECTION TO THE CENTRAL 
AMERICAN COAST ALONG THE ITCZ FROM PANAMA TO NICARAGUA. 
WAVEWATCH MODEL IS INDICATING SWELL MOVING INTO THE CENTRAL 
AMERICAN AND SOUTHERN MEXICAN COASTLINES LATE FRI THROUGH MIDDAY 
SAT. THE SWELL IS EXPECTED TO BE UP TO 17S WITH SIGNIFICANT WAVE 
HEIGHTS NEAR 7 FT. 

W OF 120W...UPPER LEVEL LOW IS CENTERED 24N120W. FURTHER W AN 
UPPER LEVEL RIDGE EXTENDS FROM 24N128W TO 21N137W. THIS IS 
DELIVERING FAIRLY DRY SUBSIDENT AIR ACROSS THE AREA...LIMITING 
THE CONVECTIVE DEVELOPMENT. AT THE SURFACE...HIGH PRES 1028 MB 
IS CENTERED OVER THE CENTRAL PACIFIC. FRESH NLY FLOW WAS 
REPORTED IN SHIP OBSERVATIONS EARLIER THIS AFTERNOON BETWEEN 
THIS HIGH AND THE BAJA COAST. QUIKSCAT IMAGERY IS ALSO HINTING 
AT MODERATE TO FRESH NELY FLOW W OF 130W N OF THE ITCZ. THE HIGH 
IS EXPECTED TO WEAKEN SLIGHTLY THROUGH SUN...ALLOWING THESE 
WINDS TO DIMINISH SLIGHTLY LATER THIS WEEKEND.

$$
CHRISTENSEN