000
AXPZ20 KNHC 171539
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC SUN OCT 17 2010

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 
0900 UTC.

...ITCZ...
THE ITCZ AXIS IS ALONG 08N85W TO 07N110W TO 10N129W THEN RESUMES 
AT 10N135W TO 08N140W. SCATTERED MODERATE TO ISOLATED STRONG  
CONVECTION NEAR 08N110W. 

...DISCUSSION...
ALOFT...
A LARGE UPPER LEVEL ANTICYCLONE CENTERED NEAR 13N129W COVERS MOST
OF THE DISCUSSION AREA W OF 120W. AN UPPER LEVEL TROUGH EXTENDS 
S FROM 30N102W TO A COL NEAR 13N116W. MODERATE TO STRONG SWLY 
WINDS OF 50-70 KT IS NOTED OVER THE NW CORNER OF THE FORECAST 
AREA. THESE WINDS ARE TRANSPORTING ABUNDANT MID/UPPER LEVEL 
MOISTURE ACROSS THE N WATERS. UPPER DIFFLUENCE IS ENHANCING 
CONVECTION NEAR THE SURFACE TROUGH LOCATED W OF 130W AND ALSO E 
OF 100W. 

SURFACE...
A MONSOON TROUGH IS EVIDENT E OF 90W IN THE ERN PORTION OF THE 
DISCUSSION AREA. A BROAD AREA OF LOW PRESSURE...ANALYZED 1009 MB 
ON THE 12 UTC SURFACE MAP...IS PROVIDING A FOCUS FOR THE WLY 
MONSOON FLOW S OF COSTA RICA AND PANAMA...WITH FRESH WINDS OF T 
15-20 KT. SHIP A8IP4 LOCATED NEAR 5N85W REPORTED SW WINDS OF 20 
KT AND SEAS TO 7 FT THIS MORNING. SCATTERED SHOWERS AND TSTMS 
ARE NOTED FROM 4N-6N E OF 82W TO THE COAST OF COLOMBIA. FURTHER 
W...A WEAK TROUGH EXTENDS FROM 14N131W TO 6N135W...AND HAS WINDS 
TO 20 KT NEAR TROUGH AXIS AND SEAS TO 8 FT. OTHERWISE A BROAD 
HIGH PRES RIDGE DOMINATES NW PORTION OF AREA.

GAP WINDS...
OCTOBER MARKS THE BEGINNING OF THE TEHUANTEPEC WIND EVENTS. THE 
10-YEAR CLIMATOLOGY INDICATES THAT ON AVERAGE 11.9 GALE-FORCE 
EVENTS AND 6.3 STORM-FORCE EVENTS OCCUR IN THE GULF OF 
TEHUANTEPEC EACH COLD SEASON...OCTOBER TO MAY. GALE FORCE EVENTS 
HAVE OCCURRED AS EARLY AS SEPTEMBER AND AS LATE AS MAY. 
STORM-FORCE EVENTS OCCUR MOST OFTEN IN JANUARY. HOWEVER...A 
STORM WIND EVENT HAS ALREADY DEVELOPED ACROSS THIS AREA A FEW 
DAYS A AGO. WINDS DIMINISHED BELOW GALE FORCE YESTERDAY NIGHT 
AND CURRENTLY NLY WINDS OF 20 KT ARE NOTED OVER THE GULF OF 
TEHUANTEPEC PER A RECENT ASCAT PASS. WEAKENING HIGH PRES IN THE 
GULF OF MEXICO AND WINDS SHIFTING TO ENE OVER THE NEXT 24 HOURS 
MEANS WINDS WILL BE BELOW 20 KT THERE WITHIN AROUND 12 HOURS. 
    
$$
GR