000
AXPZ20 KNHC 071523
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC SUN OCT 07 2007

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 1445 UTC.
  
...TROPICAL WAVE...
TROPICAL WAVE ALONG 125W MOVING W 10 TO 15 KT. NO SIGNIFICANT 
CONVECTION NOTED WITH THIS WAVE...AND ONLY WEAK CYCLONIC 
ROTATION IS NOTED AS WELL. 

...ITCZ...
INTERTROPICAL CONVERGENCE ZONE...AXIS ALONG 9N85W 7N94W 14N110W 
9N133W 10N140W. SCATTERED MODERATE CONVECTION WITHIN 75 NM S OF 
AXIS BETWEEN 108W AND 111W. SCATTERED MODERATE CONVECTION WITHIN 
120 NM BETWEEN 115W AND 118W.

SCATTERED MODERATE ISOLATED CONVECTION WITHIN 150 NM OF THE 
COAST FROM EL SALVADOR TO THE GULF OF TEHUANTEPEC.

...DISCUSSION...

E OF 120W...
A LARGE GYRE OF LOW PRESSURE IS SETTING UP AROUND CENTRAL 
AMERICA...CENTERED AROUND A LOW PRES SYSTEM 1004 MB LOCATED IN 
THE NW CARIBBEAN OFF THE COAST OF HONDURAS. IN RESPONSE TO THIS 
GENERALLY LOWERING OF PRES...SWLY CROSS-EQUATORIAL FLOW WILL 
GRADUALLY INCREASE OVER THE NEXT 2-3 DAYS S OF THE ITCZ. THE 
INCREASED LOW LEVEL CONVERGENCE WILL AID THUNDERSTORM 
DEVELOPMENT ALONG THE ITCZ...ALTHOUGH SIGNIFICANT DEVELOPMENT 
WILL BE INHIBITED BY MODERATE ELY SHEAR ALOFT ON THE S EDGE OF 
AN UPPER ANTICYCLONE OVER CENTRAL MEXICO. MEANWHILE...7-8 FT 
SWELL WITH PERIODS OF UP TO 16S WILL PUSH N INTO THE CENTRAL 
AMERICAN COAST ALONG WITH THE INCREASED SLY FLOW THROUGH TUE. 
BARRING SIGNIFICANT DEVELOPMENT OF THE LOW IN THE NW 
CARIBBEAN...TEHUANTEPEC WINDS WILL REMAIN FAIRLY LIGHT.

W OF 120W...
SHIP AND SCATTEROMETER DATA SHOW MODERATE TO FRESH NLY WINDS 
PERSISTING ON THE SERN PERIPHERY OF HIGH PRES 1030 MB CENTERED 
NW OF THE AREA. MOST OF THIS IS CONTAINED N OF ABOUT 15N. SHIP 
OBSERVATIONS INDICATED LARGE NLY SWELL CONTINUES AS WELL. THE 
CHANGE UP IN THE FORECAST WILL ARRIVE WITH A SHORT WAVE TROUGH 
NOW PUSHING N OF 40N THROUGH 140W. THIS IS DRIVING A STRONG COLD 
FRONT SWD. ALTHOUGH THE FRONT WILL NOT PENETRATE S OF 30N...IT 
WILL WEAKEN THE SURFACE HIGH AND SHIFT IT SWD. THIS WILL RESULT 
IN THE WINDS DIMINISHING...WITH ONLY MODERATE TO FRESH TRADES 
IMMEDIATELY N OF THE ITCZ BY MID WEEK. SWELL WILL GRADUALLY 
SUBSIDE AS WELL...ALTHOUGH STRONG WINDS BEHIND THE FRONT WELL TO 
THE N OF THE AREA WILL PUSH ADDITIONAL SWELL TRAINS INTO THE 
AREA N OF 20N BY LATE IN THE WEEK. 

$$
CHRISTENSEN