000
AXPZ20 KNHC 050319
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC THU NOV 05 2009

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 
0315 UTC.

...TROPICAL LOW...

.LOW PRES IS CENTERED NEAR 11N92W ESTIMATED AT 1009 MB AND IS 
DRIFTING W TOWARDS AN UPPER LEVEL TROUGH WITH INCREASING 
SOUTHWESTERLY WIND SHEAR. CURRENTLY SCATTERED MODERATE AND 
ISOLATED STRONG CONVECTION IS NOTED WITHIN 60 NM 11N91W WITH THE 
CONVECTION OCCASIONALLY BANDING N OF THE CENTER. 

...ITCZ...

THE ITCZ AXIS EXTENDS ALONG 11N86W TO 08N99W TO 14N111W TO 
08N119W TO 11N134W TO 07N140W. SCATTERED MODERATE ISOLATED 
STRONG CONVECTION IS NOTED WITHIN 90 NM OF 12N90W AND FROM 06N 
TO 11N BETWEEN 95W AND 111W AND FROM 07N TO 11N BETWEEN 120W AND 
130W.

...DISCUSSION...

AN UPPER LEVEL ANTICYCLONE IS CENTERED NEAR 13N120W WITH A SHORT 
WAVE RIDGE AMPLIFYING N TO A CREST NEAR 32N109W. THE SHORT WAVE 
RIDGE IS MERGING INTO A LONG WAVE RIDGE THAT HAS ITS MEAN AXIS N 
TO S ALONG 110W OVER ALL OF N AMERICA. A TROPICAL RIDGE EXTENDS 
SW FROM THE ANTICYCLONE TO A SHARP CREST OVER THE ITCZ AT 
08N134W WITH ANOTHER RIDGE EXTENDING SE FROM THE ANTICYCLONIC 
CENTER TO 12N108W. DEBRIS MOISTURE FROM ITCZ CONVECTION BETWEEN 
120W AND 132W...AND FROM FORMER ITCZ CONVECTION W OF THE AREA 
NEAR 06N148W...IS ADVECTED NE ALONG THE W PERIPHERY OF THIS 
TROPICAL RIDGE...ROUGHLY WITHIN 60 NM EITHER SIDE OF LINE 
10N140W TO 17N130W WHERE IT WIDENS AS IT CONTINUES NE WITHIN 150 
NM OF LINE 14N126W TO 24N111W WHERE THE PLUME SPLITS.  ONE 
BRANCH TURNS SE ACROSS THE SHORTWAVE RIDGE BACK OVER THE TROPICS 
TO NEAR 15N106W. THE SECOND BRANCH OF MOISTURE CONTINUES N 
FANNING OUT OVER NW OLD MEXICO AND CONTINUING NE OVER SOUTHERN 
ARIZONA AND CALIFORNIA. UPPER DIFFLUENCE ENHANCED A CLUSTER OF 
CONVECTION EARLIER NEAR 16N115W AND NEAR 13N113W WITH THE DEBRIS 
MOISTURE ADVECTED E ACROSS THE RIDGE TO NEAR 16N110W. 
OTHERWISE...SUBSIDENCE IS INDICATED OVER THE S SEMICIRCLE OF THE 
ANTICYCLONE AND IS SUPPRESSING ITCZ CONVECTION BETWEEN 110W AND 
119W. 

TO THE NW OF THE ANTICYCLONE...AN UPPER SHORTWAVE TROUGH HAS 
MOVED INTO THE AREA WITH ITS AXIS ALONG 138W TO THE N OF 20N. 
UPPER MOISTURE PRECEDES THIS SECOND TROUGH...ROUGHLY WITHIN 120 
NM EITHER SIDE OF LINE 32N127W TO 20N140W. OTHERWISE...THE UPPER 
LEVELS ARE DRY BETWEEN THE TROPICAL RIDGE AND THE UPPER TROUGH.

A LONG WAVE TROUGH IS MOVING ACROSS EASTERN N AMERICA WITH ITS 
AXIS EXTENDING S INTO THE AREA ALONG 32N95W INTO A SMALL UPPER 
CYCLONE AT 18N96W WITH THE TROUGH CONTINUING S TO A BASE OVER 
THE DEEP TROPICS AT 10N99W. TROPICAL STORM IDA CONTINUES OVER 
THE SW CARIBBEAN. CONVECTION IS ENHANCED ALONG THE ITCZ BETWEEN 
91W AND 111W. SOME OF THE RESULTANT DEBRIS MOISTURE IS SPREADING 
N AND NE ACROSS CENTRAL AMERICA ALONG 90W. 

AT THE LOW LEVELS...A SURFACE HIGH PRES IS NEAR 26N119W 1018 MB. 
AN INITIAL COLD FRONT IS LOSING ITS PUSH ALONG 32N132W TO 
26N140W WHILE A SECONDARY FRONT IS RAPIDLY APPROACHING ALONG 
32N137W TO 29N140W. NW WINDS ARE EXPECTED TO INCREASE BRIEFLY 
TO 20 KT OVER THE DISCUSSION AREA NW OF THE FRONT WITH NW SWELLS 
RESULTING IN SEAS TO 11 FT WITH LARGER LONG PERIOD SWELLS 
ARRIVING LATE FRI BUILDING TO ABOUT 20 FT NEAR 30N133W SAT.

GAP WINDS...
STRONG GALE FORCE WINDS EXPECTED TO CONTINUE THROUGH THE GULF OF 
TEHUANTEPEC THROUGH FRI,

$$
NELSON