000
AXPZ20 KNHC 172150
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC FRI OCT 17 2008

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 
2130 UTC.

...ITCZ...
ITCZ AXIS IS CENTERED ALONG 11N86W TO 12N95W TO 10N106 TO 
09N121W TO 12N132W TO 09N140W. SCATTERED MODERATE CONVECTION 
WITHIN 180 NM S OF AXIS BETWEEN 85W AND 98W AND 120 NM OF AXIS 
BETWEEN 94W AND 98W. SCATTERED MODERATE CONVECTION WITHIN 150 NM 
S OF AXIS BETWEEN 125W AND 128W AND WITHIN 120 NM S OF AXIS W OF 
138W.

...DISCUSSION...
A 1238 UTC QSCAT PASS REVEALED 20-30 KT N WINDS IN THE GULF OF 
TEHUANTEPEC. THIS GAP WIND EVENT IS NOT CAUSED BY THE CLASSICAL 
COLD AIR ADVECTION BEHIND A COLD FRONT...BUT RATHER BY THE W 
PERIPHERY OF THE CIRCULATION OF FORMER T.D. 16 OVER CENTRAL 
AMERICA. GFS/NAM GUIDANCE SUGGESTS THAT THIS HIGH WIND EVENT 
WILL CONTINUE FOR AT LEAST A FEW DAYS AND WILL LIKELY REACH GALE 
FORCE AS A FRONTAL BOUNDARY MAKES SOUTHWARD PROGRESS IN THE GULF 
OF MEXICO SAT NIGHT AND SUN. LAST ALTIMETER PASS OVER THE 
TEHUANTEPEC WAS ABOUT 24 HOURS AGO...MAX SEAS AT THAT TIME WERE 
NEAR 8 FT. SEAS ARE LIKELY SLIGHTLY HIGHER THAN THAT 
CURRENTLY...AND ARE EXPECTED TO BUILD TO 11 FT THIS WEEKEND.

A BROAD AREA OF LOW PRES IS CENTERED NEAR 12N94W. COMBINATION OF 
THIS FEATURE AND LOW-LEVEL CONVERGENCE ASSOCIATED WITH FORMER 
T.D.16 IS PRODUCING SCATTERED SHOWERS AND TSTMS N OF 10N E OF 
98W. THIS BROAD TROUGH HAS BEEN PRODUCING HEAVY RAINS OVER 
PORTIONS OF CENTRAL AMERICA FOR A COUPLE OF DAYS ALREADY AND IT 
WILL LIKELY CONTINUE AS THE SYSTEM MOVES SLOWLY.

FARTHER W...ONLY WEATHER MAKER TO SPEAK OF IS THE REMNANTS OF 
MARIE CENTERED NEAR 12N132W. IR IMAGES SHOW SCATTERED TSTMS 
WITHIN 150 NM N SEMICIRCLE. THIS FEATURE IS ONLY EXPECTED TO 
CONTINUE W AS A SLIGHT PERTURBATION IN THE ITCZ. EARLIER 
SCATTEROMETER DATA INDICATED 20 TO POSSIBLY 25 KT NE WINDS N OF 
THE CENTER...DUE TO THE TIGHTENED PRES GRADIENT BETWEEN IT AND 
TYPICAL SUBTROPICAL HIGH PRES TO ITS N. 

THE REMAINDER OF THE AREA IS RELATIVELY TRANQUIL WITH LITTLE 
DEEP MOISTURE...SUPPRESSED BY A SUBSIDENT ENVIRONMENT ESPECIALLY 
IN THE UPPER CONFLUENT ZONE BETWEEN AN UPPER LOW NEAR 34N127W 
AND AN UPPER RIDGE OVER CENTRAL MEXICO.

$$
CANGIALOSI