000
AXPZ20 KNHC 052156
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC THU NOV 05 2009

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

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2115 UTC.

...TROPICAL LOW...

.LOW PRES IS CENTERED NEAR 11N93W ESTIMATED AT 1009 MB AND IS 
DRIFTING N. THE SYSTEM IS ENCOUNTERING SOUTHWESTERLY WIND SHEAR. 
CURRENTLY SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS 
NOTED WITHIN 30 NM 11.5N92W...WITH THE CONVECTION OCCASIONALLY 
BANDING MAINLY N OF THE CENTER. 

...ITCZ...

THE ITCZ AXIS EXTENDS ALONG 12N87W TO 07N99W TO 13N112W TO 
08N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED 
WITHIN 150 NM EITHER SIDE OF LINE FROM 13N91W TO 08N101W TO 
14N117W TO 09N127W TO 12N132W. 

...DISCUSSION...

AN UPPER LEVEL ANTICYCLONE IS CENTERED NEAR 12N115W WITH A SHORT 
WAVE RIDGE AMPLIFYING N TO A CREST NEAR 32N115W MERGING INTO A 
LONG WAVE RIDGE THAT HAS ITS MEAN AXIS N TO S ALONG 113W OVER 
ALL OF N AMERICA. A TROPICAL RIDGE EXTENDS SW FROM THE 
ANTICYCLONE TO A SHARP CREST OVER THE ITCZ AT 10N135W WITH 
ANOTHER RIDGE EXTENDING SE FROM THE ANTICYCLONIC CENTER TO 
11N104W. UPPER LEVEL DIFFLUENCE IS ENHANCING ITCZ CONVECTION 
BETWEEN 120W AND 134W WITH THE RESULTANT DEBRIS MOISTURE 
ADVECTED NE ALONG THE W PERIPHERY OF THIS TROPICAL RIDGE... 
ROUGHLY WITHIN 150 NM EITHER SIDE OF LINE 13N126W TO 23N114W 
WHERE THE MOISTURE TURNS SE TO NEAR 17N106W. UPPER DIFFLUENCE IS 
ALSO ENHANCING CONVECTION NEAR 13N114W AND ALONG THE ITCZ 
BETWEEN 103W AND 111W BUT THE DEBRIS MOISTURE REMAINS NEAR THE 
DISSIPATING CONVECTION. 

TO THE NW OF THE ANTICYCLONE...AN UPPER SHORTWAVE TROUGH HAS 
MOVED INTO THE AREA WITH ITS MEAN AXIS N OF 18N ALONG 130W. 
UPPER MOISTURE IS NOTED N OF 24N BETWEEN 122W AND 134W.

A POSITIVE TILT LONG WAVE OVER EASTERN N AMERICA TRAILS AN UPPER 
TROUGH INTO THE DISCUSSION AREA ALONG 32N92W TO 22N97W AND INTO 
A SMALL UPPER CYCLONE AT 18N96W WITH THE TROUGH CONTINUING S TO 
A BASE OVER THE DEEP TROPICS AT 11N97W. CONVECTION IS ENHANCED 
ALONG THE ITCZ JUST E OF THIS TROUGH...BETWEEN 90W AND 96W WITH 
MOST OF THE RESULTANT DEBRIS MOISTURE SPREADING N ACROSS 
GUATEMALA AND EASTERN OLD MEXICO EVENTUALLY TURNING NE INTO A 
PLUME THAT CONTINUES ACROSS FLORIDA AND INTO THE CENTRAL ATLC.

AT THE LOW LEVELS...A SURFACE HIGH PRES IS NEAR 26N122W 1022 MB. 
AN INITIAL COLD FRONT IS LOSING ITS PUSH ALONG 32N132W TO 
24N140W WHILE A SECONDARY FRONT IS RAPIDLY APPROACHING THE 
EXTREME NW PORTION OF THE AREA. ALTHOUGH ASSOCIATED WINDS HAVE 
DIMINISHED BELOW 20 KT THE FRONTS ARE ACCOMPANIED BY NW SWELLS 
THAT WILL CONTINUE TO BUILD TO NEAR 20 FT SAT ALONG 30N BETWEEN 
130W AND 140W.

GAP WINDS...
GALE FORCE WINDS ARE EXPECTED TO CONTINUE THROUGH THE GULF OF 
TEHUANTEPEC THROUGH FRI DIMINISHING BELOW GALE FRI NIGHT.

$$
NELSON