000
AXPZ20 KNHC 290933
TWDEP 

TROPICAL WEATHER DISCUSSION     
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC TUE AUG 28 2007

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

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0845 UTC.

...SPECIAL FEATURES...

A 1005 MB LOW MOVING W AT 10 KT IS CENTERED NEAR 19N108W. SOME 
INTENSIFICATION IS NOTED AS OVERNIGHT CONVECTION GRADUALLY 
BUILDS. THE CENTER IS SITUATED IN AND AREA OF LIGHT TO MODERATE 
ELY DEEP LAYER SHEAR AND CONTINUED INTENSIFICATION IS POSSIBLE 
AT IT DRIFTS GENERALLY WNW OVER THE NEXT 24 HOURS. MODERATE TO 
STRONG CONVECTION IS NOTED NEAR THE CENTER AND WITHIN 120 NM IN 
THE S SEMICIRCLE. IN ADDITION...LARGER BANDING APPEARS TO BE 
DEVELOPING WELL TO THE E OF THE CENTER ALONG THE MEXICAN 
COAST...IN AN AREA OF FAVORABLE UPPER LEVEL DIVERGENCE.

A 1008 MB LOW CENTERED ALONG THE ITCZ NEAR 11N95W IS MOVING W AT 
10 KT. CONVECTION REMAINS WEAK AND DISORGANIZED AROUND THIS LOW 
SO FAR. SCATTERED MODERATE CONVECTION IS NOTED WELL TO THE N OF 
THE CENTER...IN THE GULF OF TEHUANTEPEC AND OFF THE GUATEMALAN 
COAST. HOWEVER...CONDITIONS ARE FAVORABLE FOR FURTHER 
DEVELOPMENT OVER THE NEXT COUPLE OF DAYS AS THIS SYSTEM MOVES TO 
THE WNW.

...TROPICAL WAVE...

A TROPICAL WAVE EXTENDS ALONG 87W N OF 10N TO ACROSS WESTERN 
NICARAGUA AND CENTRAL HONDURAS TO JUST OFF THE EASTERN YUCATAN 
COAST...MOVING W AT 10 TO 15 KT. THE WAVE REMAINS POORLY DEFINED 
OVER PACIFIC WATERS DUE TO PREDOMINANCE OF SWLY SURFACE FLOW IN 
THE AREA...AS DEPICTED IN SHIP OBSERVATIONS AND EARLIER ASCAT 
DATA. AS SUCH...LITTLE SIGNIFICANT CONVECTION IS NOTED WITH THIS 
WAVE OVER PACIFIC WATERS.

...ITCZ...

AXIS IS CENTERED ALONG 10N86W 12N104W 11N109W 12N135W 11N140W. 
SCATTERED MODERATE CONVECTION IS WITHIN 60 NM N OF THE AXIS OVER 
EASTERN PANAMA...AND WITHIN 60 NM N OF THE AXIS BETWEEN 98W AND 
99W.

...DISCUSSION...

E OF 120W...LIGHT TO MODERATE S TO SW FLOW PERSISTS S OF THE 
ITCZ ACCOMPANIED BY GENERALLY 12S PERIOD SWELL OF UP TO 8 FT. 
STRONGER SURFACE WINDS ARE NOTED ON SCATTEROMETER IMAGERY ON THE 
S SIDE OF THE DEVELOPING LOW NEAR 19N108W. SEAS MAY BUILD ALONG 
THE MEXICAN COAST OVER THE NEXT 48 HOURS AS WELL DUE TO A 
COMBINATION OF SLY SWELL ALONG WITH INCREASED WINDS AROUND THE 
DEVELOPING LOW NOW NEAR 11N95W. ALOFT...GENERALLY NE TO E FLOW 
CONTINUES OVER THE AREA...BETWEEN AN UPPER TROUGH OVER THE 
YUCATAN AND A BROAD UPPER ANTICYCLONE OVER NRN MEXICO. SHEAR 
APPEARS TO BE LIGHT ENOUGH TO NOT SERIOUSLY INHIBIT THE 
DEVELOPMENT OF THE LOW S OF BAJA...ALTHOUGH SHEAR APPEARS A 
LITTLE STRONGER OVER THE SYSTEM FURTHER TO THE SE NEAR 11N95W. 
DIVERGENCE ALOFT AT THE BASE OF THE BROAD ANTICYCLONE OVER NRN 
MEXICO IS SUPPORTING A LARGE CLUSTER OF THE NIGHTLY MODERATE TO 
STRONG THUNDERSTORMS OVER THE MEXICAN COAST FROM MANZANILLO TO 
MAZATLAN.

W OF 120W...
DEEP LAYER DRY AIR PERSISTS OVER MUCH OF THE AREA W OF 120W 
EXCEPT ALONG THE IMMEDIATE ITCZ. WEAK LOW PRES PREVIOUSLY 
LOCATED NEAR 17N133W HAS DISSIPATED LEAVING ONLY A WEAK TROUGH 
IN THE AREA FROM 18N128W TO 13N135W. 1027 MB HIGH PRES REMAINS 
CENTERED NW OF THE AREA. ONLY MODERATE NELY FLOW IS NOTED OVER 
THE AREA N OF THE ITCZ BETWEEN THE HIGH AND LOW PRES SYSTEMS 
WITH SEA HEIGHTS GENERALLY BELOW 8 FT. S OF THE ITCZ...LIGHT TO 
MODERATE SLY FLOW CONTINUES WITH UP TO 8 FT SWELL NOTED. 

$$
CHRISTENSEN