000
AXPZ20 KNHC 120938
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC THU NOV 12 2009

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 
0800 UTC.

...ITCZ...
INTERTROPICAL CONVERGENCE ZONE LIES ALONG A LINE FROM 07N77W TO 
07N105W TO 08N120W TO 11N132W TO 09N140W. SCATTERED MODERATE 
CONVECTION CAN BE FOUND WITHIN 210 NM S OF THE ITCZ AXIS BETWEEN 
122W AND 128W AND WITHIN 210 NM N OF THE ITCZ AXIS BETWEEN 127W 
AND 131W. ISOLATED MODERATE CONVECTION LIES WITHIN 75 NM EITHER 
SIDE OF THE ITCZ AXIS E OF 86W.

...DISCUSSION...

THE LONG PERIOD NW SWELL THAT HAS PUSHED SOUTH THROUGH FORECAST 
WATERS PRIMARILY W OF 100W THE LAST FEW DAYS HAS BEGUN TO 
SUBSIDE WITH SIGNIFICANT WAVE HEIGHTS DOWN TO THE 8 TO 10 FT 
RANGE. WIND WAVES STEMMING FROM THE MODERATE EASTERLY TRADE 
WINDS GENERALLY FOUND FROM 10N TO 20W W OF 120W WILL HELP KEEP 
WAVE HEIGHTS ABOVE 8 FT OVER MUCH OF THE AREA INTO THE FORECAST 
PERIOD. THE 1037 MB HIGH PRES SYSTEM NEAR 37N155W DRIVING THESE 
TRADE WINDS HAS A RIDGE AXIS EXTENDING SE ACROSS N WATERS FROM 
30N140W TO NEAR 20N110W. HOWEVER...THIS HIGH PRES RIDGE IS 
CURRENTLY BEING COMPROMISED BY A DISSIPATING COLD FRONT OVER NW 
WATERS FROM 30N132W TO 27N10W. THE 0356 UTC QUIKSCAT PASS SHOWS 
25 TO 30 KT WINDS NW OF THE FRONT. THESE WINDS WILL DIMINISH TO 
20 KT AS THEY MOVE E INTO NE WATERS OVER THE NEXT TWO DAYS. THE 
UPPER TROUGH SUPPORTING THIS FRONTAL SYSTEM WILL ALSO SHIFT E. 
THE UPPER JET ON THE LEADING EDGE OF THIS TROUGH IS TRANSPORTING 
MOISTURE ALOFT NORTHEASTWARD...WITH A SWATH OF CIRRUS FOUND FROM 
SOUTHERN CALIFORNIA SW INTO FORECAST WATERS FROM 30N122W TO 
25N130W.

TO THE S...AN ANTICYCLONE LIES NEAR 19N125W WITH A RIDGE AXIS 
EXTENDING NE INTO W TEXAS AND SW TO 06N140W. CONVECTION IS BEING 
ENHANCED OVER WESTERN FORECAST WATERS ALONG THE ITCZ WHERE UPPER 
LEVEL DIFFLUENCE IS IN PLACE DUE TO THIS RIDGE AXIS. AN UPPER 
TROUGH LIES E OF THIS RIDGE FROM SOUTH TEXAS TO NEAR PUERTO 
VALLARTA...MEXICO AND SE TO 13N114W BEFORE TURNING S TO A WEAK 
UPPER LOW NEAR 05N115W. STRONG SUBSIDENCE IS EVIDENT ON 
SATELLITE IMAGERY NW OF THE TROUGH AXIS CENTERED NEAR 18N114W. 
ANOTHER ANTICYCLONE...THIS ONE CENTERED IN THE SW CARIBBEAN NEAR 
11N79W...HAS A RIDGE AXIS EXTENDING NW OVER THROUGH CENTRAL 
AMERICA AND OVER FORECAST WATERS FROM THE GULF OF TEHUANTEPEC TO 
12N109W. THE DIFFLUENCE ALOFT ASSOCIATED WITH THIS RIDGE IS 
TRIGGERING THE SCATTERED MODERATE CONVECTION SEEN FROM 11N TO 
14N BETWEEN 102W AND 108W. WEAK DIFFLUENCE ALOFT ON THE SW SIDE 
OF THE CARIBBEAN ANTICYCLONE IS ALSO THE IMPETUS FOR SCATTERED 
MODERATE CONVECTION SEEN WITHIN 75 NM OF COAST OF COLOMBIA FROM 
03N TO 05N AS WELL AS THE ISOLATED MODERATE CONVECTION FOUND 
WITHIN 75 NM EITHER SIDE OF THE ITCZ AXIS E OF 86W..

GAP WINDS...
THE 0038 UTC QUIKSCAT PASS SHOWED STORM FORCE WINDS FUNNELING 
THROUGH THE ISTHMUS OF TEHUANTEPEC INTO THE PACIFIC FROM THE 
WESTERN GULF OF MEXICO. WINDS WILL GRADUALLY DIMINISH HERE OVER 
THE NEXT TWO DAYS AS THE DEEP LAYER LOW OFF THE CAROLINA COAST 
OF THE U.S. SHIFTS EASTWARD AND THE RIDGING OVER THE GULF OF 
MEXICO WEAKENS...ALLOWING THE PRES GRADIENT TO SLACKEN. A STORM 
WARNING IS IN PLACE FOR THE GULF OF TEHUANTEPEC THROUGH THIS 
MORNING AND WILL FURTHER DIMINISH BELOW GALE FORCE FRI MORNING.

$$
SCHAUER